diff --git a/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml b/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml index 1946e991c0..58b93c41ce 100644 --- a/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml +++ b/en_US.ISO8859-1/books/arch-handbook/mac/chapter.sgml @@ -1,7821 +1,7821 @@ Chris Costello TrustedBSD Project
chris@FreeBSD.org
 Robert Watson TrustedBSD Project
rwatson@FreeBSD.org
 The TrustedBSD MAC Framework MAC Documentation Copyright This documentation was developed for the FreeBSD Project by Chris Costello at Safeport Network Services and Network Associates Laboratories, the Security Research Division of Network Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 (CBOSS), as part of the DARPA CHATS research program. Redistribution and use in source (SGML DocBook) and 'compiled' forms (SGML, HTML, PDF, PostScript, RTF and so forth) with or without modification, are permitted provided that the following conditions are met: Redistributions of source code (SGML DocBook) must retain the above copyright notice, this list of conditions and the following disclaimer as the first lines of this file unmodified. Redistributions in compiled form (transformed to other DTDs, converted to PDF, PostScript, RTF and other formats) must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. THIS DOCUMENTATION IS PROVIDED BY THE NETWORKS ASSOCIATES TECHNOLOGY, INC "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NETWORKS ASSOCIATES TECHNOLOGY, INC BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS DOCUMENTATION, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Synopsis FreeBSD includes experimental support for several mandatory access control policies, as well as a framework for kernel security extensibility, the TrustedBSD MAC Framework. The MAC Framework provides a pluggable access control framework, permitting new security policies to be easily linked into the kernel, loaded at boot, or loaded dynamically at run-time. The framework provides a variety of features to make it easier to implement new policies, including the ability to easily tag security labels (such as confidentiality information) onto system objects. This chapter introduces the MAC policy framework and provides documentation for a sample MAC policy module. Introduction The TrustedBSD MAC framework provides a mechanism to allow the compile-time or run-time extension of the kernel access control model. New system policies may be implemented as kernel modules and linked to the kernel; if multiple policy modules are present, their results will be composed. The MAC Framework provides a variety of access control infrastructure services to assist policy writers, including support for transient and persistent policy-agnostic object security labels. This support is currently considered experimental. Policy Background Mandatory Access Control (MAC), refers to a set of access control policies that are mandatorily enforced on users by the operating system. MAC policies may be contrasted with Discretionary Access Control (DAC) protections, by which non-administrative users may (at their discretion) protect objects. In traditional UNIX systems, DAC protections include file permissions and access control lists; MAC protections include process controls preventing inter-user debugging and firewalls. A variety of MAC policies have been formulated by operating system designers and security researches, including the Multi-Level Security (MLS) confidentiality policy, the Biba integrity policy, Role-Based Access Control (RBAC), and Type Enforcement (TE). Each model bases decisions on a variety of factors, including user identity, role, and security clearance, as well as security labels on objects representing concepts such as data sensitivity and integrity. The TrustedBSD MAC Framework is capable of supporting policy modules that implement all of these policies, as well as a broad class of system hardening policies. In addition, despite the name, the MAC Framework can also be used to implement purely discretionary policies, as policy modules are given substantial flexibility in how they authorize protections. MAC Framework Kernel Architecture The TrustedBSD MAC Framework permits kernel modules to extend the operating system security policy, as well as providing infrastructure functionality required by many access control modules. If multiple policies are simultaneously loaded, the MAC Framework will usefully (for some definition of useful) compose the results of the policies. Kernel Elements The MAC Framework contains a number of kernel elements: Framework management interfaces Concurrency and synchronization primitives. Policy registration Extensible security label for kernel objects Policy entry point composition operators Label management primitives Entry point API invoked by kernel services Entry point API to policy modules Entry points implementations (policy life cycle, object life cycle/label management, access control checks). Policy-agnostic label-management system calls mac_syscall() multiplex system call Various security policies implemented as MAC policy modules Management Interfaces The TrustedBSD MAC Framework may be directly managed using sysctls, loader tunables, and system calls. In most cases, sysctls and loader tunables modify the same parameters, and control behavior such as enforcement of protections relating to various kernel subsystems. In addition, if MAC debugging support is compiled into the kernel, a variety of counters will be maintained tracking label allocation. In most cases, it is advised that per-subsystem enforcement controls not be used to control policy behavior in production environments, as they broadly impact the operation of all active policies. Instead, per-policy controls should be preferred to ensure proper policy operation. Loading and unloading of policy modules is performed using the system module management system calls and other system interfaces, including loader variables. Concurrency and Synchronization As the set of active policies may change at run-time, and the invocation of entry points is non-atomic, synchronization is required to prevent unloading or loading of new policies while an entry point invocation is progress, freezing the list of policies for the duration. This is accomplished by means of a Framework busy count. Whenever an entry point is entered, the busy count is incremented; whenever it is exited, the busy count is decremented. While the busy count is elevated, policy list changes are not permitted, and threads attempting to modify the policy list will sleep until the list is not busy. The busy count is protected by a mutex, and a condition variable is used to wake up sleepers waiting on policy list modifications. Various optimizations are used to reduce the overhead of the busy count, including avoiding the full cost of incrementing and decrementing if the list is empty or contains only static entries (policies that are loaded before the system starts, and cannot be unloaded). Policy Registration The MAC Framework maintains two lists of active policies: a static list, and a dynamic list. The lists differ only with regards to their locking semantics: an elevated reference count is not required to make use of the static list. When kernel modules containing MAC Framework policies are loaded, the policy module will use SYSINIT to invoke a registration function; when a policy module is unloaded, SYSINIT will likewise invoke a de-registration function. Registration may fail if a policy module is loaded more than once, if insufficient resources are available for the registration (for example, the policy might require labeling and insufficient labeling state might be available), or other policy prerequisites might not be met (some policies may only be loaded prior to boot). Likewise, de-registration may fail if a policy refuses an unload. Entry Points Kernel services interact with the MAC Framework in two ways: they invoke a series of APIs to notify the framework of relevant events, and they a policy-agnostic label structure in security-relevant objects. This label structure is maintained by the MAC Framework via label management entry points, and permits the Framework to offer a labeling service to policy modules through relatively non-invasive changes to the kernel subsystem maintaining the object. For example, label structures have been added to processes, process credentials, sockets, pipes, vnodes, Mbufs, network interfaces, IP reassembly queues, and a variety of other security-relevant structures. Kernel services also invoke the MAC Framework when they perform important security decisions, permitting policy modules to augment those decisions based on their own criteria (possibly including data stored in security labels). Policy Composition When more than one policy module is loaded into the kernel at a time, the results of the policy modules will be composed by the framework using a composition operator. This operator is currently hard-coded, and requires that all active policies must approve a request for it to occur. As policies may return a variety of error conditions (success, access denied, object doesn't exist, ...), a precedence operator selects the resulting error from the set of errors returned by policies. While it is not guaranteed that the resulting composition will be useful or secure, we've found that it is for many useful selections of policies. Labeling Support As many interesting access control extensions rely on security labels on objects, the MAC Framework provides a set of policy-agnostic label management system calls covering a variety of user-exposed objects. Common label types include partition identifiers, sensitivity labels, integrity labels, compartments, domains, roles, and types. Policy modules participate in the internalization and externalization of string-based labels provides by user applications, and can expose multiple label elements to applications if desired. In-memory labels are stored in struct label, which consists of a fixed-length array of unions, each holding a void * pointer and a long. Policies registering for label storage will be assigned a "slot" identifier, which may be used to dereference the label storage. The semantics of the storage are left entirely up to the policy module: modules are provided with a variety of entry points associated with the kernel object life cycle, including initialization, association/creation, and destruction. Using these interfaces, it is possible to implement reference counting and other storage mechanisms. Direct access to the kernel object is generally not required by policy modules to retrieve a label, as the MAC Framework generally passes both a pointer to the object and a direct pointer to the object's label into entry points. Initialization entry points frequently include a blocking disposition flag indicating whether or not an initialization is permitted to block; if blocking is not permitted, a failure may be returned to cancel allocation of the label. This may occur, for example, in the network stack during interrupt handling, where blocking is not permitted. Due to the performance cost of maintaining labels on in-flight network packets (Mbufs), policies must specifically declare a requirement that Mbuf labels be allocated. Dynamically loaded policies making use of labels must be able to handle the case where their init function has not been called on an object, as objects may already exist when the policy is loaded. In the case of file system labels, special support is provided for the persistent storage of security labels in extended attributes. Where available, EA transactions are used to permit consistent compound updates of security labels on vnodes. Currently, if a labeled policy permits dynamic unloading, its state slot cannot be reclaimed. System Calls The MAC Framework implements a number of system calls: most of these calls support the policy-agnostic label retrieval and manipulation APIs exposed to user applications. The label management calls accept a label description structure, struct mac, which contains a series of MAC label elements. Each element contains a character string name, and character string value. Each policy will be given the chance to claim a particular element name, permitting policies to expose multiple independent elements if desired. Policy modules perform the internalization and externalization between kernel labels and user-provided labels via entry points, permitting a variety of semantics. Label management system calls are generally wrapped by user library functions to perform memory allocation and error handling. In addition, mac_syscall() permits policy modules to create new system calls without allocating system calls. mac_execve() permits an atomic process credential label change when executing a new image. MAC Policy Architecture Security policies are either linked directly into the kernel, or compiled into loadable kernel modules that may be loaded at boot, or dynamically using the module loading system calls at runtime. Policy modules interact with the system through a set of declared entry points, providing access to a stream of system events and permitting the policy to influence access control decisions. Each policy contains a number of elements: Optional configuration parameters for policy. Centralized implementation of the policy logic and parameters. Optional implementation of policy life cycle events, such as initialization and destruction. Optional support for initializing, maintaining, and destroying labels on selected kernel objects. Optional support for user process inspection and modification of labels on selected objects. Implementation of selected access control entry points that are of interest to the policy. Declaration of policy identity, module entry points, and policy properties. Policy Declaration Modules may be declared using the MAC_POLICY_SET() macro, which names the policy, provides a reference to the MAC entry point vector, provides load-time flags determining how the policy framework should handle the policy, and optionally requests the allocation of label state by the framework. static struct mac_policy_ops mac_policy_ops = { .mpo_destroy = mac_policy_destroy, .mpo_init = mac_policy_init, .mpo_init_bpfdesc_label = mac_policy_init_bpfdesc_label, .mpo_init_cred_label = mac_policy_init_label, /* ... */ .mpo_check_vnode_setutimes = mac_policy_check_vnode_setutimes, .mpo_check_vnode_stat = mac_policy_check_vnode_stat, .mpo_check_vnode_write = mac_policy_check_vnode_write, }; The MAC policy entry point vector, mac_policy_ops in this example, associates functions defined in the module with specific entry points. A complete listing of available entry points and their prototypes may be found in the MAC entry point reference section. Of specific interest during module registration are the .mpo_destroy and .mpo_init entry points. .mpo_init will be invoked once a policy is successfully registered with the module framework but prior to any other entry points becoming active. This permits the policy to perform any policy-specific allocation and initialization, such as initialization of any data or locks. .mpo_destroy will be invoked when a policy module is unloaded to permit releasing of any allocated memory and destruction of locks. Currently, these two entry points are invoked with the MAC policy list mutex held to prevent any other entry points from being invoked: this will be changed, but in the mean time, policies should be careful about what kernel primitives they invoke so as to avoid lock ordering or sleeping problems. The policy declaration's module name field exists so that the module may be uniquely identified for the purposes of module dependencies. An appropriate string should be selected. The full string name of the policy is displayed to the user via the kernel log during load and unload events, and also exported when providing status information to userland processes. Policy Flags The policy declaration flags field permits the module to provide the framework with information about its capabilities at the time the module is loaded. Currently, three flags are defined: MPC_LOADTIME_FLAG_UNLOADOK This flag indicates that the policy module may be unloaded. If this flag is not provided, then the policy framework will reject requests to unload the module. This flag might be used by modules that allocate label state and are unable to free that state at runtime. MPC_LOADTIME_FLAG_NOTLATE This flag indicates that the policy module must be loaded and initialized early in the boot process. If the flag is specified, attempts to register the module following boot will be rejected. The flag may be used by policies that require pervasive labeling of all system objects, and cannot handle objects that have not been properly initialized by the policy. MPC_LOADTIME_FLAG_LABELMBUFS This flag indicates that the policy module requires labeling of Mbufs, and that memory should always be allocated for the storage of Mbuf labels. By default, the MAC Framework will not allocate label storage for Mbufs unless at least one loaded policy has this flag set. This measurably improves network performance when policies do not require Mbuf labeling. A kernel option, MAC_ALWAYS_LABEL_MBUF, exists to force the MAC Framework to allocate Mbuf label storage regardless of the setting of this flag, and may be useful in some environments. Policies using the MPC_LOADTIME_FLAG_LABELMBUFS without the MPC_LOADTIME_FLAG_NOTLATE flag set must be able to correctly handle NULL Mbuf label pointers passed into entry points. This is necessary as in-flight Mbufs without label storage may persist after a policy enabling Mbuf labeling has been loaded. If a policy is loaded before the network subsystem is active (i.e., the policy is not being loaded late), then all Mbufs are guaranteed to have label storage. Policy Entry Points Four classes of entry points are offered to policies registered with the framework: entry points associated with the registration and management of policies, entry points denoting initialization, creation, destruction, and other life cycle events for kernel objects, events associated with access control decisions that the policy module may influence, and calls associated with the management of labels on objects. In addition, a mac_syscall() entry point is provided so that policies may extend the kernel interface without registering new system calls. Policy module writers should be aware of the kernel locking strategy, as well as what object locks are available during which entry points. Writers should attempt to avoid deadlock scenarios by avoiding grabbing non-leaf locks inside of entry points, and also follow the locking protocol for object access and modification. In particular, writers should be aware that while necessary locks to access objects and their labels are generally held, sufficient locks to modify an object or its label may not be present for all entry points. Locking information for arguments is documented in the MAC framework entry point document. Policy entry points will pass a reference to the object label along with the object itself. This permits labeled policies to be unaware of the internals of the object yet still make decisions based on the label. The exception to this is the process credential, which is assumed to be understood by policies as a first class security object in the kernel. Policies that do not implement labels on kernel objects will be passed NULL pointers for label arguments to entry points. MAC Policy Entry Point Reference General-Purpose Module Entry Points - <function>&mac.mpo;_init</function + <function>&mac.mpo;_init</function> void &mac.mpo;_init struct mac_policy_conf *conf &mac.thead; conf MAC policy definition Policy load event. The policy list mutex is held, so caution should be applied. <function>&mac.mpo;_destroy</function> void &mac.mpo;_destroy struct mac_policy_conf *conf &mac.thead; conf MAC policy definition Policy load event. The policy list mutex is held, so caution should be applied. <function>&mac.mpo;_syscall</function> int &mac.mpo;_syscall struct thread *td int call void *arg &mac.thead; td Calling thread call Syscall number arg Pointer to syscall arguments This entry point provides a policy-multiplexed system call so that policies may provide additional services to user processes without registering specific system calls. The policy name provided during registration is used to demux calls from userland, and the arguments will be forwarded to this entry point. When implementing new services, security modules should be sure to invoke appropriate access control checks from the MAC framework as needed. For example, if a policy implements an augmented signal functionality, it should call the necessary signal access control checks to invoke the MAC framework and other registered policies. Modules must currently perform the copyin() of the syscall data on their own. <function>&mac.mpo;_thread_userret</function> void &mac.mpo;_thread_userret struct thread *td &mac.thead; td Returning thread This entry point permits policy modules to perform MAC-related events when a thread returns to user space. This is required for policies that have floating process labels, as it's not always possible to acquire the process lock at arbitrary points in the stack during system call processing; process labels might represent traditional authentication data, process history information, or other data. Label Operations <function>&mac.mpo;_init_bpfdesc_label</function> void &mac.mpo;_init_bpfdesc_label struct label *label &mac.thead; label New label to apply Initialize the label on a newly instantiated bpfdesc (BPF descriptor) <function>&mac.mpo;_init_cred_label</function> void &mac.mpo;_init_cred_label struct label *label &mac.thead; label New label to initialize Initialize the label for a newly instantiated user credential. <function>&mac.mpo;_init_devfsdirent_label</function> void &mac.mpo;_init_devfsdirent_label struct label *label &mac.thead; label New label to apply Initialize the label on a newly instantiated devfs entry. <function>&mac.mpo;_init_ifnet_label</function> void &mac.mpo;_init_ifnet_label struct label *label &mac.thead; label New label to apply Initialize the label on a newly instantiated network interface. <function>&mac.mpo;_init_ipq_label</function> void &mac.mpo;_init_ipq_label struct label *label int flag &mac.thead; label New label to apply flag Blocking/non-blocking &man.malloc.9;; see below Initialize the label on a newly instantiated IP fragment reassembly queue. The flag field may be one of M_WAITOK and M_NOWAIT, and should be employed to avoid performing a blocking &man.malloc.9; during this initialization call. IP fragment reassembly queue allocation frequently occurs in performance sensitive environments, and the implementation should be careful to avoid blocking or long-lived operations. This entry point is permitted to fail resulting in the failure to allocate the IP fragment reassembly queue. <function>&mac.mpo;_init_mbuf_label</function> void &mac.mpo;_init_mbuf_label int flag struct label *label &mac.thead; flag Blocking/non-blocking &man.malloc.9;; see below label Policy label to initialize Initialize the label on a newly instantiated mbuf packet header (mbuf). The flag field may be one of M_WAITOK and M_NOWAIT, and should be employed to avoid performing a blocking &man.malloc.9; during this initialization call. Mbuf allocation frequently occurs in performance sensitive environments, and the implementation should be careful to avoid blocking or long-lived operations. This entry point is permitted to fail resulting in the failure to allocate the mbuf header. <function>&mac.mpo;_init_mount_label</function> void &mac.mpo;_init_mount_label struct label *mntlabel struct label *fslabel &mac.thead; mntlabel Policy label to be initialized for the mount itself fslabel Policy label to be initialized for the file system Initialize the labels on a newly instantiated mount point. <function>&mac.mpo;_init_mount_fs_label</function> void &mac.mpo;_init_mount_fs_label struct label *label &mac.thead; label Label to be initialized Initialize the label on a newly mounted file system. <function>&mac.mpo;_init_pipe_label</function> void &mac.mpo;_init_pipe_label struct label*label &mac.thead; label Label to be filled in Initialize a label for a newly instantiated pipe. <function>&mac.mpo;_init_socket_label</function> void &mac.mpo;_init_socket_label struct label *label int flag &mac.thead; label New label to initialize flag &man.malloc.9; flags Initialize a label for a newly instantiated socket. <function>&mac.mpo;_init_socket_peer_label</function> void &mac.mpo;_init_socket_peer_label struct label *label int flag &mac.thead; label New label to initialize flag &man.malloc.9; flags Initialize the peer label for a newly instantiated socket. <function>&mac.mpo;_init_proc_label</function> void &mac.mpo;_init_proc_label struct label *label &mac.thead; label New label to initialize Initialize the label for a newly instantiated process. <function>&mac.mpo;_init_vnode_label</function> void &mac.mpo;_init_vnode_label struct label *label &mac.thead; label New label to initialize Initialize the label on a newly instantiated vnode. <function>&mac.mpo;_destroy_bpfdesc_label</function> void &mac.mpo;_destroy_bpfdesc_label struct label *label &mac.thead; label bpfdesc label Destroy the label on a BPF descriptor. In this entry point a policy should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_cred_label</function> void &mac.mpo;_destroy_cred_label struct label *label &mac.thead; label Label being destroyed Destroy the label on a credential. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_devfsdirent_label</function> void &mac.mpo;_destroy_devfsdirent_label struct label *label &mac.thead; label Label being destroyed Destroy the label on a devfs entry. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_ifnet_label</function> void &mac.mpo;_destroy_ifnet_label struct label *label &mac.thead; label Label being destroyed Destroy the label on a removed interface. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_ipq_label</function> void &mac.mpo;_destroy_ipq_label struct label *label &mac.thead; label Label being destroyed Destroy the label on an IP fragment queue. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_mbuf_label</function> void &mac.mpo;_destroy_mbuf_label struct label *label &mac.thead; label Label being destroyed Destroy the label on an mbuf header. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_mount_label</function> void &mac.mpo;_destroy_mount_label struct label *label &mac.thead; label Mount point label being destroyed Destroy the labels on a mount point. In this entry point, a policy module should free the internal storage associated with mntlabel so that they may be destroyed. <function>&mac.mpo;_destroy_mount_label</function> void &mac.mpo;_destroy_mount_label struct label *mntlabel struct label *fslabel &mac.thead; mntlabel Mount point label being destroyed fslabel File system label being destroyed> Destroy the labels on a mount point. In this entry point, a policy module should free the internal storage associated with mntlabel and fslabel so that they may be destroyed. <function>&mac.mpo;_destroy_socket_label</function> void &mac.mpo;_destroy_socket_label struct label *label &mac.thead; label Socket label being destroyed Destroy the label on a socket. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_socket_peer_label</function> void &mac.mpo;_destroy_socket_peer_label struct label *peerlabel &mac.thead; peerlabel Socket peer label being destroyed Destroy the peer label on a socket. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_pipe_label</function> void &mac.mpo;_destroy_pipe_label struct label *label &mac.thead; label Pipe label Destroy the label on a pipe. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_proc_label</function> void &mac.mpo;_destroy_proc_label struct label *label &mac.thead; label Process label Destroy the label on a process. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_destroy_vnode_label</function> void &mac.mpo;_destroy_vnode_label struct label *label &mac.thead; label Process label Destroy the label on a vnode. In this entry point, a policy module should free any internal storage associated with label so that it may be destroyed. <function>&mac.mpo;_copy_mbuf_label</function> void &mac.mpo;_copy_mbuf_label struct label *src struct label *dest &mac.thead; src Source label dest Destination label Copy the label information in src into dest. <function>&mac.mpo;_copy_pipe_label</function> void &mac.mpo;_copy_pipe_label struct label *src struct label *dest &mac.thead; src Source label dest Destination label Copy the label information in src into dest. <function>&mac.mpo;_copy_vnode_label</function> void &mac.mpo;_copy_vnode_label struct label *src struct label *dest &mac.thead; src Source label dest Destination label Copy the label information in src into dest. <function>&mac.mpo;_externalize_cred_label</function> int &mac.mpo;_externalize_cred_label &mac.externalize.paramdefs; &mac.thead; &mac.externalize.tbody; &mac.externalize.para; <function>&mac.mpo;_externalize_ifnet_label</function> int &mac.mpo;_externalize_ifnet_label &mac.externalize.paramdefs; &mac.thead; &mac.externalize.tbody; &mac.externalize.para; <function>&mac.mpo;_externalize_pipe_label</function> int &mac.mpo;_externalize_pipe_label &mac.externalize.paramdefs; &mac.thead; &mac.externalize.tbody; &mac.externalize.para; <function>&mac.mpo;_externalize_socket_label</function> int &mac.mpo;_externalize_socket_label &mac.externalize.paramdefs; &mac.thead; &mac.externalize.tbody; &mac.externalize.para; <function>&mac.mpo;_externalize_socket_peer_label</function> int &mac.mpo;_externalize_socket_peer_label &mac.externalize.paramdefs; &mac.thead; &mac.externalize.tbody; &mac.externalize.para; <function>&mac.mpo;_externalize_vnode_label</function> int &mac.mpo;_externalize_vnode_label &mac.externalize.paramdefs; &mac.thead; &mac.externalize.tbody; &mac.externalize.para; <function>&mac.mpo;_internalize_cred_label</function> int &mac.mpo;_internalize_cred_label &mac.internalize.paramdefs; &mac.thead; &mac.internalize.tbody; &mac.internalize.para; <function>&mac.mpo;_internalize_ifnet_label</function> int &mac.mpo;_internalize_ifnet_label &mac.internalize.paramdefs; &mac.thead; &mac.internalize.tbody; &mac.internalize.para; <function>&mac.mpo;_internalize_pipe_label</function> int &mac.mpo;_internalize_pipe_label &mac.internalize.paramdefs; &mac.thead; &mac.internalize.tbody; &mac.internalize.para; <function>&mac.mpo;_internalize_socket_label</function> int &mac.mpo;_internalize_socket_label &mac.internalize.paramdefs; &mac.thead; &mac.internalize.tbody; &mac.internalize.para; <function>&mac.mpo;_internalize_vnode_label</function> int &mac.mpo;_internalize_vnode_label &mac.internalize.paramdefs; &mac.thead; &mac.internalize.tbody; &mac.internalize.para; Label Events This class of entry points is used by the MAC framework to permit policies to maintain label information on kernel objects. For each labeled kernel object of interest to a MAC policy, entry points may be registered for relevant life cycle events. All objects implement initialization, creation, and destruction hooks. Some objects will also implement relabeling, allowing user processes to change the labels on objects. Some objects will also implement object-specific events, such as label events associated with IP reassembly. A typical labeled object will have the following life cycle of entry points: Label initialization o (object-specific wait) \ Label creation o \ Relabel events, o--<--. Various object-specific, | | Access control events ~-->--o \ Label destruction o Label initialization permits policies to allocate memory and set initial values for labels without context for the use of the object. The label slot allocated to a policy will be zeroed by default, so some policies may not need to perform initialization. Label creation occurs when the kernel structure is associated with an actual kernel object. For example, Mbufs may be allocated and remain unused in a pool until they are required. mbuf allocation causes label initialization on the mbuf to take place, but mbuf creation occurs when the mbuf is associated with a datagram. Typically, context will be provided for a creation event, including the circumstances of the creation, and labels of other relevant objects in the creation process. For example, when an mbuf is created from a socket, the socket and its label will be presented to registered policies in addition to the new mbuf and its label. Memory allocation in creation events is discouraged, as it may occur in performance sensitive ports of the kernel; in addition, creation calls are not permitted to fail so a failure to allocate memory cannot be reported. Object specific events do not generally fall into the other broad classes of label events, but will generally provide an opportunity to modify or update the label on an object based on additional context. For example, the label on an IP fragment reassembly queue may be updated during the MAC_UPDATE_IPQ entry point as a result of the acceptance of an additional mbuf to that queue. Access control events are discussed in detail in the following section. Label destruction permits policies to release storage or state associated with a label during its association with an object so that the kernel data structures supporting the object may be reused or released. In addition to labels associated with specific kernel objects, an additional class of labels exists: temporary labels. These labels are used to store update information submitted by user processes. These labels are initialized and destroyed as with other label types, but the creation event is MAC_INTERNALIZE, which accepts a user label to be converted to an in-kernel representation. File System Object Labeling Event Operations <function>&mac.mpo;_associate_vnode_devfs</function> void &mac.mpo;_associate_vnode_devfs struct mount *mp struct label *fslabel struct devfs_dirent *de struct label *delabel struct vnode *vp struct label *vlabel &mac.thead; mp Devfs mount point fslabel Devfs file system label (mp->mnt_fslabel) de Devfs directory entry delabel Policy label associated with de vp vnode associated with de vlabel Policy label associated with vp Fill in the label (vlabel) for a newly created devfs vnode based on the devfs directory entry passed in de and its label. <function>&mac.mpo;_associate_vnode_extattr</function> int &mac.mpo;_associate_vnode_extattr struct mount *mp struct label *fslabel struct vnode *vp struct label *vlabel &mac.thead; mp File system mount point fslabel File system label vp Vnode to label vlabel Policy label associated with vp Attempt to retrieve the label for vp from the file system extended attributes. Upon success, the value 0 is returned. Should extended attribute retrieval not be supported, an accepted fallback is to copy fslabel into vlabel. In the event of an error, an appropriate value for errno should be returned. <function>&mac.mpo;_associate_vnode_singlelabel</function> void &mac.mpo;_associate_vnode_singlelabel struct mount *mp struct label *fslabel struct vnode *vp struct label *vlabel &mac.thead; mp File system mount point fslabel File system label vp Vnode to label vlabel Policy label associated with vp On non-multilabel file systems, this entry point is called to set the policy label for vp based on the file system label, fslabel. <function>&mac.mpo;_create_devfs_device</function> void &mac.mpo;_create_devfs_device dev_t dev struct devfs_dirent *devfs_dirent struct label *label &mac.thead; dev Device corresponding with devfs_dirent devfs_dirent Devfs directory entry to be labeled. label Label for devfs_dirent to be filled in. Fill out the label on a devfs_dirent being created for the passed device. This call will be made when the device file system is mounted, regenerated, or a new device is made available. <function>&mac.mpo;_create_devfs_directory</function> void &mac.mpo;_create_devfs_directory char *dirname int dirnamelen struct devfs_dirent *devfs_dirent struct label *label &mac.thead; dirname Name of directory being created namelen Length of string dirname devfs_dirent Devfs directory entry for directory being created. Fill out the label on a devfs_dirent being created for the passed directory. This call will be made when the device file system is mounted, regenerated, or a new device requiring a specific directory hierarchy is made available. <function>&mac.mpo;_create_devfs_symlink</function> void &mac.mpo;_create_devfs_symlink struct ucred *cred struct mount *mp struct devfs_dirent *dd struct label *ddlabel struct devfs_dirent *de struct label *delabel &mac.thead; cred Subject credential mp Devfs mount point dd Link destination ddlabel Label associated with dd de Symlink entry delabel Label associated with de Fill in the label (delabel) for a newly created &man.devfs.5; symbolic link entry. <function>&mac.mpo;_create_vnode_extattr</function> int &mac.mpo;_create_vnode_extattr struct ucred *cred struct mount *mp struct label *fslabel struct vnode *dvp struct label *dlabel struct vnode *vp struct label *vlabel struct componentname *cnp &mac.thead; cred Subject credential mount File system mount point label File system label dvp Parent directory vnode dlabel Label associated with dvp vp Newly created vnode vlabel Policy label associated with vp cnp Component name for vp Write out the label for vp to the appropriate extended attribute. If the write succeeds, fill in vlabel with the label, and return 0. Otherwise, return an appropriate error. <function>&mac.mpo;_create_mount</function> void &mac.mpo;_create_mount struct ucred *cred struct mount *mp struct label *mnt struct label *fslabel &mac.thead; cred Subject credential mp Object; file system being mounted mntlabel Policy label to be filled in for mp fslabel Policy label for the file system mp mounts. Fill out the labels on the mount point being created by the passed subject credential. This call will be made when a new file system is mounted. <function>&mac.mpo;_create_root_mount</function> void &mac.mpo;_create_root_mount struct ucred *cred struct mount *mp struct label *mntlabel struct label *fslabel &mac.thead; See . Fill out the labels on the mount point being created by the passed subject credential. This call will be made when the root file system is mounted, after &mac.mpo;_create_mount;. <function>&mac.mpo;_relabel_vnode</function> void &mac.mpo;_relabel_vnode struct ucred *cred struct vnode *vp struct label *vnodelabel struct label *newlabel &mac.thead; cred Subject credential vp vnode to relabel vnodelabel Existing policy label for vp newlabel New, possibly partial label to replace vnodelabel Update the label on the passed vnode given the passed update vnode label and the passed subject credential. <function>&mac.mpo;_setlabel_vnode_extattr</function> int &mac.mpo;_setlabel_vnode_extattr struct ucred *cred struct vnode *vp struct label *vlabel struct label *intlabel &mac.thead; cred Subject credential vp Vnode for which the label is being written vlabel Policy label associated with vp intlabel Label to write out Write out the policy from intlabel to an extended attribute. This is called from vop_stdcreatevnode_ea. <function>&mac.mpo;_update_devfsdirent</function> void &mac.mpo;_update_devfsdirent struct devfs_dirent *devfs_dirent struct label *direntlabel struct vnode *vp struct label *vnodelabel &mac.thead; devfs_dirent Object; devfs directory entry direntlabel Policy label for devfs_dirent to be updated. vp Parent vnode Locked vnodelabel Policy label for vp Update the devfs_dirent label from the passed devfs vnode label. This call will be made when a devfs vnode has been successfully relabeled to commit the label change such that it lasts even if the vnode is recycled. It will also be made when when a symlink is created in devfs, following a call to mac_vnode_create_from_vnode to initialize the vnode label. IPC Object Labeling Event Operations <function>&mac.mpo;_create_mbuf_from_socket</function> void &mac.mpo;_create_mbuf_from_socket struct socket *so struct label *socketlabel struct mbuf *m struct label *mbuflabel &mac.thead; socket Socket Socket locking WIP socketlabel Policy label for socket m Object; mbuf mbuflabel Policy label to fill in for m Set the label on a newly created mbuf header from the passed socket label. This call is made when a new datagram or message is generated by the socket and stored in the passed mbuf. <function>&mac.mpo;_create_pipe</function> void &mac.mpo;_create_pipe struct ucred *cred struct pipe *pipe struct label *pipelabel &mac.thead; cred Subject credential pipe Pipe pipelabel Policy label associated with pipe Set the label on a newly created pipe from the passed subject credential. This call is made when a new pipe is created. <function>&mac.mpo;_create_socket</function> void &mac.mpo;_create_socket struct ucred *cred struct socket *so struct label *socketlabel &mac.thead; cred Subject credential Immutable so Object; socket to label socketlabel Label to fill in for so Set the label on a newly created socket from the passed subject credential. This call is made when a socket is created. <function>&mac.mpo;_create_socket_from_socket</function> void &mac.mpo;_create_socket_from_socket struct socket *oldsocket struct label *oldsocketlabel struct socket *newsocket struct label *newsocketlabel &mac.thead; oldsocket Listening socket oldsocketlabel Policy label associated with oldsocket newsocket New socket newsocketlabel Policy label associated with newsocketlabel Label a socket, newsocket, newly &man.accept.2;ed, based on the &man.listen.2; socket, oldsocket. <function>&mac.mpo;_relabel_pipe</function> void &mac.mpo;_relabel_pipe struct ucred *cred struct pipe *pipe struct label *oldlabel struct label *newlabel &mac.thead; cred Subject credential pipe Pipe oldlabel Current policy label associated with pipe newlabel Policy label update to apply to pipe Apply a new label, newlabel, to pipe. <function>&mac.mpo;_relabel_socket</function> void &mac.mpo;_relabel_socket struct ucred *cred struct socket *so struct label *oldlabel struct label *newlabel &mac.thead; cred Subject credential Immutable so Object; socket oldlabel Current label for so newlabel Label update for so Update the label on a socket from the passed socket label update. <function>&mac.mpo;_set_socket_peer_from_mbuf</function> void &mac.mpo;_set_socket_peer_from_mbuf struct mbuf *mbuf struct label *mbuflabel struct label *oldlabel struct label *newlabel &mac.thead; mbuf First datagram received over socket mbuflabel Label for mbuf oldlabel Current label for the socket newlabel Policy label to be filled out for the socket Set the peer label on a stream socket from the passed mbuf label. This call will be made when the first datagram is received by the stream socket, with the exception of Unix domain sockets. <function>&mac.mpo;_set_socket_peer_from_socket</function> void &mac.mpo;_set_socket_peer_from_socket struct socket *oldsocket struct label *oldsocketlabel struct socket *newsocket struct label *newsocketpeerlabel &mac.thead; oldsocket Local socket oldsocketlabel Policy label for oldsocket newsocket Peer socket newsocketpeerlabel Policy label to fill in for newsocket Set the peer label on a stream UNIX domain socket from the passed remote socket endpoint. This call will be made when the socket pair is connected, and will be made for both endpoints. Network Object Labeling Event Operations <function>&mac.mpo;_create_bpfdesc</function> void &mac.mpo;_create_bpfdesc struct ucred *cred struct bpf_d *bpf_d struct label *bpflabel &mac.thead; cred Subject credential Immutable bpf_d Object; bpf descriptor bpf Policy label to be filled in for bpf_d Set the label on a newly created BPF descriptor from the passed subject credential. This call will be made when a BPF device node is opened by a process with the passed subject credential. <function>&mac.mpo;_create_ifnet</function> void &mac.mpo;_create_ifnet struct ifnet *ifnet struct label *ifnetlabel &mac.thead; ifnet Network interface ifnetlabel Policy label to fill in for ifnet Set the label on a newly created interface. This call may be made when a new physical interface becomes available to the system, or when a pseudo-interface is instantiated during the boot or as a result of a user action. <function>&mac.mpo;_create_ipq</function> void &mac.mpo;_create_ipq struct mbuf *fragment struct label *fragmentlabel struct ipq *ipq struct label *ipqlabel &mac.thead; fragment First received IP fragment fragmentlabel Policy label for fragment ipq IP reassembly queue to be labeled ipqlabel Policy label to be filled in for ipq Set the label on a newly created IP fragment reassembly queue from the mbuf header of the first received fragment. <function>&mac.mpo;_create_datagram_from_ipq</function> void &mac.mpo;_create_create_datagram_from_ipq struct ipq *ipq struct label *ipqlabel struct mbuf *datagram struct label *datagramlabel &mac.thead; ipq IP reassembly queue ipqlabel Policy label for ipq datagram Datagram to be labeled datagramlabel Policy label to be filled in for datagramlabel Set the label on a newly reassembled IP datagram from the IP fragment reassembly queue from which it was generated. <function>&mac.mpo;_create_fragment</function> void &mac.mpo;_create_fragment struct mbuf *datagram struct label *datagramlabel struct mbuf *fragment struct label *fragmentlabel &mac.thead; datagram Datagram datagramlabel Policy label for datagram fragment Fragment to be labeled fragmentlabel Policy label to be filled in for datagram Set the label on the mbuf header of a newly created IP fragment from the label on the mbuf header of the datagram it was generate from. <function>&mac.mpo;_create_mbuf_from_mbuf</function> void &mac.mpo;_create_mbuf_from_mbuf struct mbuf *oldmbuf struct label *oldmbuflabel struct mbuf *newmbuf struct label *newmbuflabel &mac.thead; oldmbuf Existing (source) mbuf oldmbuflabel Policy label for oldmbuf newmbuf New mbuf to be labeled newmbuflabel Policy label to be filled in for newmbuf Set the label on the mbuf header of a newly created datagram from the mbuf header of an existing datagram. This call may be made in a number of situations, including when an mbuf is re-allocated for alignment purposes. <function>&mac.mpo;_create_mbuf_linklayer</function> void &mac.mpo;_create_mbuf_linklayer struct ifnet *ifnet struct label *ifnetlabel struct mbuf *mbuf struct label *mbuflabel &mac.thead; ifnet Network interface ifnetlabel Policy label for ifnet mbuf mbuf header for new datagram mbuflabel Policy label to be filled in for mbuf Set the label on the mbuf header of a newly created datagram generated for the purposes of a link layer response for the passed interface. This call may be made in a number of situations, including for ARP or ND6 responses in the IPv4 and IPv6 stacks. <function>&mac.mpo;_create_mbuf_from_bpfdesc</function> void &mac.mpo;_create_mbuf_from_bpfdesc struct bpf_d *bpf_d struct label *bpflabel struct mbuf *mbuf struct label *mbuflabel &mac.thead; bpf_d BPF descriptor bpflabel Policy label for bpflabel mbuf New mbuf to be labeled mbuflabel Policy label to fill in for mbuf Set the label on the mbuf header of a newly created datagram generated using the passed BPF descriptor. This call is made when a write is performed to the BPF device associated with the passed BPF descriptor. <function>&mac.mpo;_create_mbuf_from_ifnet</function> void &mac.mpo;_create_mbuf_from_ifnet struct ifnet *ifnet struct label *ifnetlabel struct mbuf *mbuf struct label *mbuflabel &mac.thead; ifnet Network interface ifnetlabel Policy label for ifnetlabel mbuf mbuf header for new datagram mbuflabel Policy label to be filled in for mbuf Set the label on the mbuf header of a newly created datagram generated from the passed network interface. <function>&mac.mpo;_create_mbuf_multicast_encap</function> void &mac.mpo;_create_mbuf_multicast_encap struct mbuf *oldmbuf struct label *oldmbuflabel struct ifnet *ifnet struct label *ifnetlabel struct mbuf *newmbuf struct label *newmbuflabel &mac.thead; oldmbuf mbuf header for existing datagram oldmbuflabel Policy label for oldmbuf ifnet Network interface ifnetlabel Policy label for ifnet newmbuf mbuf header to be labeled for new datagram newmbuflabel Policy label to be filled in for newmbuf Set the label on the mbuf header of a newly created datagram generated from the existing passed datagram when it is processed by the passed multicast encapsulation interface. This call is made when an mbuf is to be delivered using the virtual interface. <function>&mac.mpo;_create_mbuf_netlayer</function> void &mac.mpo;_create_mbuf_netlayer struct mbuf *oldmbuf struct label *oldmbuflabel struct mbuf *newmbuf struct label *newmbuflabel &mac.thead; oldmbuf Received datagram oldmbuflabel Policy label for oldmbuf newmbuf Newly created datagram newmbuflabel Policy label for newmbuf Set the label on the mbuf header of a newly created datagram generated by the IP stack in response to an existing received datagram (oldmbuf). This call may be made in a number of situations, including when responding to ICMP request datagrams. <function>&mac.mpo;_fragment_match</function> int &mac.mpo;_fragment_match struct mbuf *fragment struct label *fragmentlabel struct ipq *ipq struct label *ipqlabel &mac.thead; fragment IP datagram fragment fragmentlabel Policy label for fragment ipq IP fragment reassembly queue ipqlabel Policy label for ipq Determine whether an mbuf header containing an IP datagram (fragment) fragment matches the label of the passed IP fragment reassembly queue (ipq). Return (1) for a successful match, or (0) for no match. This call is made when the IP stack attempts to find an existing fragment reassembly queue for a newly received fragment; if this fails, a new fragment reassembly queue may be instantiated for the fragment. Policies may use this entry point to prevent the reassembly of otherwise matching IP fragments if policy does not permit them to be reassembled based on the label or other information. <function>&mac.mpo;_relabel_ifnet</function> void &mac.mpo;_relabel_ifnet struct ucred *cred struct ifnet *ifnet struct label *ifnetlabel struct label *newlabel &mac.thead; cred Subject credential ifnet Object; Network interface ifnetlabel Policy label for ifnet newlabel Label update to apply to ifnet Update the label of network interface, ifnet, based on the passed update label, newlabel, and the passed subject credential, cred. <function>&mac.mpo;_update_ipq</function> void &mac.mpo;_update_ipq struct mbuf *fragment struct label *fragmentlabel struct ipq *ipq struct label *ipqlabel &mac.thead; mbuf IP fragment mbuflabel Policy label for mbuf ipq IP fragment reassembly queue ipqlabel Policy label to be updated for ipq Update the label on an IP fragment reassembly queue (ipq) based on the acceptance of the passed IP fragment mbuf header (mbuf). Process Labeling Event Operations <function>&mac.mpo;_create_cred</function> void &mac.mpo;_create_cred struct ucred *parent_cred struct ucred *child_cred &mac.thead; parent_cred Parent subject credential child_cred Child subject credential Set the label of a newly created subject credential from the passed subject credential. This call will be made when &man.crcopy.9; is invoked on a newly created struct ucred. This call should not be confused with a process forking or creation event. <function>&mac.mpo;_execve_transition</function> void &mac.mpo;_execve_transition struct ucred *old struct ucred *new struct vnode *vp struct label *vnodelabel &mac.thead; old Existing subject credential Immutable new New subject credential to be labeled vp File to execute Locked vnodelabel Policy label for vp Update the label of a newly created subject credential (new) from the passed existing subject credential (old) based on a label transition caused by executing the passed vnode (vp). This call occurs when a process executes the passed vnode and one of the policies returns a success from the mpo_execve_will_transition entry point. Policies may choose to implement this call simply by invoking mpo_create_cred and passing the two subject credentials so as not to implement a transitioning event. Policies should not leave this entry point unimplemented if they implement mpo_create_cred, even if they do not implement mpo_execve_will_transition. <function>&mac.mpo;_execve_will_transition</function> int &mac.mpo;_execve_will_transition struct ucred *old struct vnode *vp struct label *vnodelabel &mac.thead; old Subject credential prior to &man.execve.2; Immutable vp File to execute vnodelabel Policy label for vp Determine whether the policy will want to perform a transition event as a result of the execution of the passed vnode by the passed subject credential. Return 1 if a transition is required, 0 if not. Even if a policy returns 0, it should behave correctly in the presence of an unexpected invocation of mpo_execve_transition, as that call may happen as a result of another policy requesting a transition. <function>&mac.mpo;_create_proc0</function> void &mac.mpo;_create_proc0 struct ucred *cred &mac.thead; cred Subject credential to be filled in Create the subject credential of process 0, the parent of all kernel processes. <function>&mac.mpo;_create_proc1</function> void &mac.mpo;_create_proc1 struct ucred *cred &mac.thead; cred Subject credential to be filled in Create the subject credential of process 1, the parent of all user processes. <function>&mac.mpo;_relabel_cred</function> void &mac.mpo;_relabel_cred struct ucred *cred struct label *newlabel &mac.thead; cred Subject credential newlabel Label update to apply to cred Update the label on a subject credential from the passed update label. Access Control Checks Access control entry points permit policy modules to influence access control decisions made by the kernel. Generally, although not always, arguments to an access control entry point will include one or more authorizing credentials, information (possibly including a label) for any other objects involved in the operation. An access control entry point may return 0 to permit the operation, or an &man.errno.2; error value. The results of invoking the entry point across various registered policy modules will be composed as follows: if all modules permit the operation to succeed, success will be returned. If one or modules returns a failure, a failure will be returned. If more than one module returns a failure, the errno value to return to the user will be selected using the following precedence, implemented by the error_select() function in kern_mac.c: Most precedence EDEADLK EINVAL ESRCH EACCES Least precedence EPERM If none of the error values returned by all modules are listed in the precedence chart then an arbitrarily selected value from the set will be returned. In general, the rules provide precedence to errors in the following order: kernel failures, invalid arguments, object not present, access not permitted, other. <function>&mac.mpo;_check_bpfdesc_receive</function> int &mac.mpo;_check_bpfdesc_receive struct bpf_d *bpf_d struct label *bpflabel struct ifnet *ifnet struct label *ifnetlabel &mac.thead; bpf_d Subject; BPF descriptor bpflabel Policy label for bpf_d ifnet Object; network interface ifnetlabel Policy label for ifnet Determine whether the MAC framework should permit datagrams from the passed interface to be delivered to the buffers of the passed BPF descriptor. Return (0) for success, or an errno value for failure Suggested failure: EACCES for label mismatches, EPERM for lack of privilege. <function>&mac.mpo;_check_kenv_dump</function> int &mac.mpo;_check_kenv_dump struct ucred *cred &mac.thead; cred Subject credential Determine whether the subject should be allowed to retrieve the kernel environment (see &man.kenv.2;). <function>&mac.mpo;_check_kenv_get</function> int &mac.mpo;_check_kenv_get struct ucred *cred char *name &mac.thead; cred Subject credential name Kernel environment variable name Determine whether the subject should be allowed to retrieve the value of the specified kernel environment variable. <function>&mac.mpo;_check_kenv_set</function> int &mac.mpo;_check_kenv_set struct ucred *cred char *name &mac.thead; cred Subject credential name Kernel environment variable name Determine whether the subject should be allowed to set the specified kernel environment variable. <function>&mac.mpo;_check_kenv_unset</function> int &mac.mpo;_check_kenv_unset struct ucred *cred char *name &mac.thead; cred Subject credential name Kernel environment variable name Determine whether the subject should be allowed to unset the specified kernel environment variable. <function>&mac.mpo;_check_kld_load</function> int &mac.mpo;_check_kld_load struct ucred *cred struct vnode *vp struct label *vlabel &mac.thead; cred Subject credential vp Kernel module vnode vlabel Label associated with vp Determine whether the subject should be allowed to load the specified module file. <function>&mac.mpo;_check_kld_stat</function> int &mac.mpo;_check_kld_stat struct ucred *cred &mac.thead; cred Subject credential Determine whether the subject should be allowed to retrieve a list of loaded kernel module files and associated statistics. <function>&mac.mpo;_check_kld_unload</function> int &mac.mpo;_check_kld_unload struct ucred *cred &mac.thead; cred Subject credential Determine whether the subject should be allowed to unload a kernel module. <function>&mac.mpo;_check_pipe_ioctl</function> int &mac.mpo;_check_pipe_ioctl struct ucred *cred struct pipe *pipe struct label *pipelabel unsigned long cmd void *data &mac.thead; cred Subject credential pipe Pipe pipelabel Policy label associated with pipe cmd &man.ioctl.2; command data &man.ioctl.2; data Determine whether the subject should be allowed to make the specified &man.ioctl.2; call. <function>&mac.mpo;_check_pipe_poll</function> int &mac.mpo;_check_pipe_poll struct ucred *cred struct pipe *pipe struct label *pipelabel &mac.thead; cred Subject credential pipe Pipe pipelabel Policy label associated with pipe Determine whether the subject should be allowed to poll pipe. <function>&mac.mpo;_check_pipe_read</function> int &mac.mpo;_check_pipe_read struct ucred *cred struct pipe *pipe struct label *pipelabel &mac.thead; cred Subject credential pipe Pipe pipelabel Policy label associated with pipe Determine whether the subject should be allowed read access to pipe. <function>&mac.mpo;_check_pipe_relabel</function> int &mac.mpo;_check_pipe_relabel struct ucred *cred struct pipe *pipe struct label *pipelabel struct label *newlabel &mac.thead; cred Subject credential pipe Pipe pipelabel Current policy label associated with pipe newlabel Label update to pipelabel Determine whether the subject should be allowed to relabel pipe. <function>&mac.mpo;_check_pipe_stat</function> int &mac.mpo;_check_pipe_stat struct ucred *cred struct pipe *pipe struct label *pipelabel &mac.thead; cred Subject credential pipe Pipe pipelabel Policy label associated with pipe Determine whether the subject should be allowed to retrieve statistics related to pipe. <function>&mac.mpo;_check_pipe_write</function> int &mac.mpo;_check_pipe_write struct ucred *cred struct pipe *pipe struct label *pipelabel &mac.thead; cred Subject credential pipe Pipe pipelabel Policy label associated with pipe Determine whether the subject should be allowed to write to pipe. <function>&mac.mpo;_check_socket_bind</function> int &mac.mpo;_check_socket_bind struct ucred *cred struct socket *socket struct label *socketlabel struct sockaddr *sockaddr &mac.thead; cred Subject credential socket Socket to be bound socketlabel Policy label for socket sockaddr Address of socket <function>&mac.mpo;_check_socket_connect</function> int &mac.mpo;_check_socket_connect struct ucred *cred struct socket *socket struct label *socketlabel struct sockaddr *sockaddr &mac.thead; cred Subject credential socket Socket to be connected socketlabel Policy label for socket sockaddr Address of socket Determine whether the subject credential (cred) can connect the passed socket (socket) to the passed socket address (sockaddr). Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatches, EPERM for lack of privilege. <function>&mac.mpo;_check_socket_receive</function> int &mac.mpo;_check_socket_receive struct ucred *cred struct socket *so struct label *socketlabel &mac.thead; cred Subject credential so Socket socketlabel Policy label associated with so Determine whether the subject should be allowed to receive information from the socket so. <function>&mac.mpo;_check_socket_send</function> int &mac.mpo;_check_socket_send struct ucred *cred struct socket *so struct label *socketlabel &mac.thead; cred Subject credential so Socket socketlabel Policy label associated with so Determine whether the subject should be allowed to send information across the socket so. <function>&mac.mpo;_check_cred_visible</function> int &mac.mpo;_check_cred_visible struct ucred *u1 struct ucred *u2 &mac.thead; u1 Subject credential u2 Object credential Determine whether the subject credential u1 can see other subjects with the passed subject credential u2. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatches, EPERM for lack of privilege, or ESRCH to hide visibility. This call may be made in a number of situations, including inter-process status sysctls used by ps, and in procfs lookups. <function>&mac.mpo;_check_socket_visible</function> int &mac.mpo;_check_socket_visible struct ucred *cred struct socket *socket struct label *socketlabel &mac.thead; cred Subject credential socket Object; socket socketlabel Policy label for socket <function>&mac.mpo;_check_ifnet_relabel</function> int &mac.mpo;_check_ifnet_relabel struct ucred *cred struct ifnet *ifnet struct label *ifnetlabel struct label *newlabel &mac.thead; cred Subject credential ifnet Object; network interface ifnetlabel Existing policy label for ifnet newlabel Policy label update to later be applied to ifnet Determine whether the subject credential can relabel the passed network interface to the passed label update. <function>&mac.mpo;_check_socket_relabel</function> int &mac.mpo;_check_socket_relabel struct ucred *cred struct socket *socket struct label *socketlabel struct label *newlabel &mac.thead; cred Subject credential socket Object; socket socketlabel Existing policy label for socket newlabel Label update to later be applied to socketlabel Determine whether the subject credential can relabel the passed socket to the passed label update. <function>&mac.mpo;_check_cred_relabel</function> int &mac.mpo;_check_cred_relabel struct ucred *cred struct label *newlabel &mac.thead; cred Subject credential newlabel Label update to later be applied to cred Determine whether the subject credential can relabel itself to the passed label update. <function>&mac.mpo;_check_vnode_relabel</function> int &mac.mpo;_check_vnode_relabel struct ucred *cred struct vnode *vp struct label *vnodelabel struct label *newlabel &mac.thead; cred Subject credential Immutable vp Object; vnode Locked vnodelabel Existing policy label for vp newlabel Policy label update to later be applied to vp Determine whether the subject credential can relabel the passed vnode to the passed label update. <function>&mac.mpo;_check_mount_stat</function> int &mac.mpo;_check_mount_stat struct ucred *cred struct mount *mp struct label *mountlabel &mac.thead; cred Subject credential mp Object; file system mount mountlabel Policy label for mp Determine whether the subject credential can see the results of a statfs performed on the file system. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatches or EPERM for lack of privilege. This call may be made in a number of situations, including during invocations of &man.statfs.2; and related calls, as well as to determine what file systems to exclude from listings of file systems, such as when &man.getfsstat.2; is invoked. <function>&mac.mpo;_check_proc_debug</function> int &mac.mpo;_check_proc_debug struct ucred *cred struct proc *proc &mac.thead; cred Subject credential Immutable proc Object; process Determine whether the subject credential can debug the passed process. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, EPERM for lack of privilege, or ESRCH to hide visibility of the target. This call may be made in a number of situations, including use of the &man.ptrace.2; and &man.ktrace.2; APIs, as well as for some types of procfs operations. <function>&mac.mpo;_check_vnode_access</function> int &mac.mpo;_check_vnode_access struct ucred *cred struct vnode *vp struct label *label int flags &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp flags &man.access.2; flags Determine how invocations of &man.access.2; and related calls by the subject credential should return when performed on the passed vnode using the passed access flags. This should generally be implemented using the same semantics used in &mac.mpo;_check_vnode_open. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatches or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_chdir</function> int &mac.mpo;_check_vnode_chdir struct ucred *cred struct vnode *dvp struct label *dlabel &mac.thead; cred Subject credential dvp Object; vnode to &man.chdir.2; into dlabel Policy label for dvp Determine whether the subject credential can change the process working directory to the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_chroot</function> int &mac.mpo;_check_vnode_chroot struct ucred *cred struct vnode *dvp struct label *dlabel &mac.thead; cred Subject credential dvp Directory vnode dlabel Policy label associated with dvp Determine whether the subject should be allowed to &man.chroot.2; into the specified directory (dvp). <function>&mac.mpo;_check_vnode_create</function> int &mac.mpo;_check_vnode_create struct ucred *cred struct vnode *dvp struct label *dlabel struct componentname *cnp struct vattr *vap &mac.thead; cred Subject credential dvp Object; vnode dlabel Policy label for dvp cnp Component name for dvp vap vnode attributes for vap Determine whether the subject credential can create a vnode with the passed parent directory, passed name information, and passed attribute information. Return 0 for success, or an errno value for failure. Suggested failure: EACCES. for label mismatch, or EPERM for lack of privilege. This call may be made in a number of situations, including as a result of calls to &man.open.2; with O_CREAT, &man.mknod.2;, &man.mkfifo.2;, and others. <function>&mac.mpo;_check_vnode_delete</function> int &mac.mpo;_check_vnode_delete struct ucred *cred struct vnode *dvp struct label *dlabel struct vnode *vp void *label struct componentname *cnp &mac.thead; cred Subject credential dvp Parent directory vnode dlabel Policy label for dvp vp Object; vnode to delete label Policy label for vp cnp Component name for vp Determine whether the subject credential can delete a vnode from the passed parent directory and passed name information. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. This call may be made in a number of situations, including as a result of calls to &man.unlink.2; and &man.rmdir.2;. Policies implementing this entry point should also implement mpo_check_rename_to to authorize deletion of objects as a result of being the target of a rename. <function>&mac.mpo;_check_vnode_deleteacl</function> int &mac.mpo;_check_vnode_deleteacl struct ucred *cred struct vnode *vp struct label *label acl_type_t type &mac.thead; cred Subject credential Immutable vp Object; vnode Locked label Policy label for vp type ACL type Determine whether the subject credential can delete the ACL of passed type from the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_exec</function> int &mac.mpo;_check_vnode_exec struct ucred *cred struct vnode *vp struct label *label &mac.thead; cred Subject credential vp Object; vnode to execute label Policy label for vp Determine whether the subject credential can execute the passed vnode. Determination of execute privilege is made separately from decisions about any transitioning event. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_getacl</function> int &mac.mpo;_check_vnode_getacl struct ucred *cred struct vnode *vp struct label *label acl_type_t type &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp type ACL type Determine whether the subject credential can retrieve the ACL of passed type from the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_getextattr</function> int &mac.mpo;_check_vnode_getextattr struct ucred *cred struct vnode *vp struct label *label int attrnamespace const char *name struct uio *uio &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp attrnamespace Extended attribute namespace name Extended attribute name uio I/O structure pointer; see &man.uio.9; Determine whether the subject credential can retrieve the extended attribute with the passed namespace and name from the passed vnode. Policies implementing labeling using extended attributes may be interested in special handling of operations on those extended attributes. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_link</function> int &mac.mpo;_check_vnode_link struct ucred *cred struct vnode *dvp struct label *dlabel struct vnode *vp struct label *label struct componentname *cnp &mac.thead; cred Subject credential dvp Directory vnode dlabel Policy label associated with dvp vp Link destination vnode label Policy label associated with vp cnp Component name for the link being created Determine whether the subject should be allowed to create a link to the vnode vp with the name specified by cnp. <function>&mac.mpo;_check_vnode_mmap</function> int &mac.mpo;_check_vnode_mmap struct ucred *cred struct vnode *vp struct label *label int prot &mac.thead; cred Subject credential vp Vnode to map label Policy label associated with vp prot Mmap protections (see &man.mmap.2;) Determine whether the subject should be allowed to map the vnode vp with the protections specified in prot. <function>&mac.mpo;_check_vnode_mmap_downgrade</function> void &mac.mpo;_check_vnode_mmap_downgrade struct ucred *cred struct vnode *vp struct label *label int *prot &mac.thead; cred See . vp label prot Mmap protections to be downgraded Downgrade the mmap protections based on the subject and object labels. <function>&mac.mpo;_check_vnode_mprotect</function> int &mac.mpo;_check_vnode_mprotect struct ucred *cred struct vnode *vp struct label *label int prot &mac.thead; cred Subject credential vp Mapped vnode prot Memory protections Determine whether the subject should be allowed to set the specified memory protections on memory mapped from the vnode vp. <function>&mac.mpo;_check_vnode_poll</function> int &mac.mpo;_check_vnode_poll struct ucred *active_cred struct ucred *file_cred struct vnode *vp struct label *label &mac.thead; active_cred Subject credential file_cred Credential associated with the struct file vp Polled vnode label Policy label associated with vp Determine whether the subject should be allowed to poll the vnode vp. <function>&mac.mpo;_check_vnode_rename_from</function> int &mac.mpo;_vnode_rename_from struct ucred *cred struct vnode *dvp struct label *dlabel struct vnode *vp struct label *label struct componentname *cnp &mac.thead; cred Subject credential dvp Directory vnode dlabel Policy label associated with dvp vp Vnode to be renamed label Policy label associated with vp cnp Component name for vp Determine whether the subject should be allowed to rename the vnode vp to something else. <function>&mac.mpo;_check_vnode_rename_to</function> int &mac.mpo;_check_vnode_rename_to struct ucred *cred struct vnode *dvp struct label *dlabel struct vnode *vp struct label *label int samedir struct componentname *cnp &mac.thead; cred Subject credential dvp Directory vnode dlabel Policy label associated with dvp vp Overwritten vnode label Policy label associated with vp samedir Boolean; 1 if the source and destination directories are the same cnp Destination component name Determine whether the subject should be allowed to rename to the vnode vp, into the directory dvp, or to the name represented by cnp. If there is no existing file to overwrite, vp and label will be NULL. <function>&mac.mpo;_check_socket_listen</function> int &mac.mpo;_check_socket_listen struct ucred *cred struct socket *socket struct label *socketlabel &mac.thead; cred Subject credential socket Object; socket socketlabel Policy label for socket Determine whether the subject credential can listen on the passed socket. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_lookup</function> int &mac.mpo;_check_vnode_lookup struct ucred *cred struct vnode *dvp struct label *dlabel struct componentname *cnp &mac.thead; cred Subject credential dvp Object; vnode dlabel Policy label for dvp cnp Component name being looked up Determine whether the subject credential can perform a lookup in the passed directory vnode for the passed name. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_open</function> int &mac.mpo;_check_vnode_open struct ucred *cred struct vnode *vp struct label *label int acc_mode &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp acc_mode &man.open.2; access mode Determine whether the subject credential can perform an open operation on the passed vnode with the passed access mode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_readdir</function> int &mac.mpo;_check_vnode_readdir struct ucred *cred struct vnode *dvp struct label *dlabel &mac.thead; cred Subject credential dvp Object; directory vnode dlabel Policy label for dvp Determine whether the subject credential can perform a readdir operation on the passed directory vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_readlink</function> int &mac.mpo;_check_vnode_readlink struct ucred *cred struct vnode *vp struct label *label &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp Determine whether the subject credential can perform a readlink operation on the passed symlink vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. This call may be made in a number of situations, including an explicit readlink call by the user process, or as a result of an implicit readlink during a name lookup by the process. <function>&mac.mpo;_check_vnode_revoke</function> int &mac.mpo;_check_vnode_revoke struct ucred *cred struct vnode *vp struct label *label &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp Determine whether the subject credential can revoke access to the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_setacl</function> int &mac.mpo;_check_vnode_setacl struct ucred *cred struct vnode *vp struct label *label acl_type_t type struct acl *acl &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp type ACL type acl ACL Determine whether the subject credential can set the passed ACL of passed type on the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_setextattr</function> int &mac.mpo;_check_vnode_setextattr struct ucred *cred struct vnode *vp struct label *label int attrnamespace const char *name struct uio *uio &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp attrnamespace Extended attribute namespace name Extended attribute name uio I/O structure pointer; see &man.uio.9; Determine whether the subject credential can set the extended attribute of passed name and passed namespace on the passed vnode. Policies implementing security labels backed into extended attributes may want to provide additional protections for those attributes. Additionally, policies should avoid making decisions based on the data referenced from uio, as there is a potential race condition between this check and the actual operation. The uio may also be NULL if a delete operation is being performed. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_setflags</function> int &mac.mpo;_check_vnode_setflags struct ucred *cred struct vnode *vp struct label *label u_long flags &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp flags File flags; see &man.chflags.2; Determine whether the subject credential can set the passed flags on the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_setmode</function> int &mac.mpo;_check_vnode_setmode struct ucred *cred struct vnode *vp struct label *label mode_t mode &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp mode File mode; see &man.chmod.2; Determine whether the subject credential can set the passed mode on the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_setowner</function> int &mac.mpo;_check_vnode_setowner struct ucred *cred struct vnode *vp struct label *label uid_t uid gid_t gid &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp uid User ID gid Group ID Determine whether the subject credential can set the passed uid and passed gid as file uid and file gid on the passed vnode. The IDs may be set to (-1) to request no update. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_vnode_setutimes</function> int &mac.mpo;_check_vnode_setutimes struct ucred *cred struct vnode *vp struct label *label struct timespec atime struct timespec mtime &mac.thead; cred Subject credential vp Object; vp label Policy label for vp atime Access time; see &man.utimes.2; mtime Modification time; see &man.utimes.2; Determine whether the subject credential can set the passed access timestamps on the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_proc_sched</function> int &mac.mpo;_check_proc_sched struct ucred *ucred struct proc *proc &mac.thead; cred Subject credential proc Object; process Determine whether the subject credential can change the scheduling parameters of the passed process. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, EPERM for lack of privilege, or ESRCH to limit visibility. See &man.setpriority.2; for more information. <function>&mac.mpo;_check_proc_signal</function> int &mac.mpo;_check_proc_signal struct ucred *cred struct proc *proc int signal &mac.thead; cred Subject credential proc Object; process signal Signal; see &man.kill.2; Determine whether the subject credential can deliver the passed signal to the passed process. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, EPERM for lack of privilege, or ESRCH to limit visibility. <function>&mac.mpo;_check_vnode_stat</function> int &mac.mpo;_check_vnode_stat struct ucred *cred struct vnode *vp struct label *label &mac.thead; cred Subject credential vp Object; vnode label Policy label for vp Determine whether the subject credential can stat the passed vnode. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. See &man.stat.2; for more information. <function>&mac.mpo;_check_ifnet_transmit</function> int &mac.mpo;_check_ifnet_transmit struct ucred *cred struct ifnet *ifnet struct label *ifnetlabel struct mbuf *mbuf struct label *mbuflabel &mac.thead; cred Subject credential ifnet Network interface ifnetlabel Policy label for ifnet mbuf Object; mbuf to be sent mbuflabel Policy label for mbuf Determine whether the network interface can transmit the passed mbuf. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_socket_deliver</function> int &mac.mpo;_check_socket_deliver struct ucred *cred struct ifnet *ifnet struct label *ifnetlabel struct mbuf *mbuf struct label *mbuflabel &mac.thead; cred Subject credential ifnet Network interface ifnetlabel Policy label for ifnet mbuf Object; mbuf to be delivered mbuflabel Policy label for mbuf Determine whether the socket may receive the datagram stored in the passed mbuf header. Return 0 for success, or an errno value for failure. Suggested failures: EACCES for label mismatch, or EPERM for lack of privilege. <function>&mac.mpo;_check_socket_visible</function> int &mac.mpo;_check_socket_visible struct ucred *cred struct socket *so struct label *socketlabel &mac.thead; cred Subject credential Immutable so Object; socket socketlabel Policy label for so Determine whether the subject credential cred can "see" the passed socket (socket) using system monitoring functions, such as those employed by &man.netstat.8; and &man.sockstat.1;. Return 0 for success, or an errno value for failure. Suggested failure: EACCES for label mismatches, EPERM for lack of privilege, or ESRCH to hide visibility. <function>&mac.mpo;_check_system_acct</function> int &mac.mpo;_check_system_acct struct ucred *ucred struct vnode *vp struct label *vlabel &mac.thead; ucred Subject credential vp Accounting file; &man.acct.5; vlabel Label associated with vp Determine whether the subject should be allowed to enable accounting, based on its label and the label of the accounting log file. <function>&mac.mpo;_check_system_nfsd</function> int &mac.mpo;_check_system_nfsd struct ucred *cred &mac.thead; cred Subject credential Determine whether the subject should be allowed to call &man.nfssvc.2;. <function>&mac.mpo;_check_system_reboot</function> int &mac.mpo;_check_system_reboot struct ucred *cred int howto &mac.thead; cred Subject credential howto howto parameter from &man.reboot.2; Determine whether the subject should be allowed to reboot the system in the specified manner. <function>&mac.mpo;_check_system_settime</function> int &mac.mpo;_check_system_settime struct ucred *cred &mac.thead; cred Subject credential Determine whether the user should be allowed to set the system clock. <function>&mac.mpo;_check_system_swapon</function> int &mac.mpo;_check_system_swapon struct ucred *cred struct vnode *vp struct label *vlabel &mac.thead; cred Subject credential vp Swap device vlabel Label associated with vp Determine whether the subject should be allowed to add vp as a swap device. <function>&mac.mpo;_check_system_sysctl</function> int &mac.mpo;_check_system_sysctl struct ucred *cred int *name u_int *namelen void *old size_t *oldlenp int inkernel void *new size_t newlen &mac.thead; cred Subject credential name See &man.sysctl.3; namelen old oldlenp inkernel Boolean; 1 if called from kernel new See &man.sysctl.3; newlen Determine whether the subject should be allowed to make the specified &man.sysctl.3; transaction. Label Management Calls Relabel events occur when a user process has requested that the label on an object be modified. A two-phase update occurs: first, an access control check will be performed to determine if the update is both valid and permitted, and then the update itself is performed via a separate entry point. Relabel entry points typically accept the object, object label reference, and an update label submitted by the process. Memory allocation during relabel is discouraged, as relabel calls are not permitted to fail (failure should be reported earlier in the relabel check). Userland Architecture The TrustedBSD MAC Framework includes a number of policy-agnostic elements, including MAC library interfaces for abstractly managing labels, modifications to the system credential management and login libraries to support the assignment of MAC labels to users, and a set of tools to monitor and modify labels on processes, files, and network interfaces. More details on the user architecture will be added to this section in the near future. APIs for Policy-Agnostic Label Management The TrustedBSD MAC Framework provides a number of library and system calls permitting applications to manage MAC labels on objects using a policy-agnostic interface. This permits applications to manipulate labels for a variety of policies without being written to support specific policies. These interfaces are used by general-purpose tools such as &man.ifconfig.8;, &man.ls.1; and &man.ps.1; to view labels on network interfaces, files, and processes. The APIs also support MAC management tools including &man.getfmac.8;, &man.getpmac.8;, &man.setfmac.8;, &man.setfsmac.8;, and &man.setpmac.8;. The MAC APIs are documented in &man.mac.3;. Applications handle MAC labels in two forms: an internalized form used to return and set labels on processes and objects (mac_t), and externalized form based on C strings appropriate for storage in configuration files, display to the user, or input from the user. Each MAC label contains a number of elements, each consisting of a name and value pair. Policy modules in the kernel bind to specific names and interpret the values in policy-specific ways. In the externalized string form, labels are represented by a comma-delimited list of name and value pairs separated by the / character. Labels may be directly converted to and from text using provided APIs; when retrieving labels from the kernel, internalized label storage must first be prepared for the desired label element set. Typically, this is done in one of two ways: using &man.mac.prepare.3; and an arbitrary list of desired label elements, or one of the variants of the call that loads a default element set from the &man.mac.conf.5; configuration file. Per-object defaults permit application writers to usefully display labels associated with objects without being aware of the policies present in the system. Currently, direct manipulation of label elements other than by conversion to a text string, string editing, and conversion back to an internalized label is not supported by the MAC library. Such interfaces may be added in the future if they prove necessary for application writers. Binding of Labels to Users The standard user context management interface, &man.setusercontext.3;, has been modified to retrieve MAC labels associated with a user's class from &man.login.conf.5;. These labels are then set along with other user context when either LOGIN_SETALL is specified, or when LOGIN_SETMAC is explicitly specified. It is expected that, in a future version of FreeBSD, the MAC label database will be separated from the login.conf user class abstraction, and be maintained in a separate database. However, the &man.setusercontext.3; API should remain the same following such a change. Conclusion The TrustedBSD MAC framework permits kernel modules to augment the system security policy in a highly integrated manner. They may do this based on existing object properties, or based on label data that is maintained with the assistance of the MAC framework. The framework is sufficiently flexible to implement a variety of policy types, including information flow security policies such as MLS and Biba, as well as policies based on existing BSD credentials or file protections. Policy authors may wish to consult this documentation as well as existing security modules when implementing a new security service. diff --git a/en_US.ISO8859-1/books/developers-handbook/tools/chapter.sgml b/en_US.ISO8859-1/books/developers-handbook/tools/chapter.sgml index 2458e94c02..0f7f09e77b 100644 --- a/en_US.ISO8859-1/books/developers-handbook/tools/chapter.sgml +++ b/en_US.ISO8859-1/books/developers-handbook/tools/chapter.sgml @@ -1,2359 +1,2359 @@ James Raynard Written by Murray Stokely Modifications for the Developer's Handbook by Programming Tools Synopsis This chapter is an introduction to using some of the programming tools supplied with FreeBSD, although much of it will be applicable to many other versions of Unix. It does not attempt to describe coding in any detail. Most of the chapter assumes little or no previous programming knowledge, although it is hoped that most programmers will find something of value in it. Introduction FreeBSD offers an excellent development environment. Compilers for C, C++, and Fortran and an assembler come with the basic system, not to mention a Perl interpreter and classic Unix tools such as sed and awk. If that is not enough, there are many more compilers and interpreters in the Ports collection. FreeBSD is very compatible with standards such as POSIX and ANSI C, as well with its own BSD heritage, so it is possible to write applications that will compile and run with little or no modification on a wide range of platforms. However, all this power can be rather overwhelming at first if you have never written programs on a Unix platform before. This document aims to help you get up and running, without getting too deeply into more advanced topics. The intention is that this document should give you enough of the basics to be able to make some sense of the documentation. Most of the document requires little or no knowledge of programming, although it does assume a basic competence with using Unix and a willingness to learn! Introduction to Programming A program is a set of instructions that tell the computer to do various things; sometimes the instruction it has to perform depends on what happened when it performed a previous instruction. This section gives an overview of the two main ways in which you can give these instructions, or commands as they are usually called. One way uses an interpreter, the other a compiler. As human languages are too difficult for a computer to understand in an unambiguous way, commands are usually written in one or other languages specially designed for the purpose. Interpreters With an interpreter, the language comes as an environment, where you type in commands at a prompt and the environment executes them for you. For more complicated programs, you can type the commands into a file and get the interpreter to load the file and execute the commands in it. If anything goes wrong, many interpreters will drop you into a debugger to help you track down the problem. The advantage of this is that you can see the results of your commands immediately, and mistakes can be corrected readily. The biggest disadvantage comes when you want to share your programs with someone. They must have the same interpreter, or you must have some way of giving it to them, and they need to understand how to use it. Also users may not appreciate being thrown into a debugger if they press the wrong key! From a performance point of view, interpreters can use up a lot of memory, and generally do not generate code as efficiently as compilers. In my opinion, interpreted languages are the best way to start if you have not done any programming before. This kind of environment is typically found with languages like Lisp, Smalltalk, Perl and Basic. It could also be argued that the Unix shell (sh, csh) is itself an interpreter, and many people do in fact write shell scripts to help with various housekeeping tasks on their machine. Indeed, part of the original Unix philosophy was to provide lots of small utility programs that could be linked together in shell scripts to perform useful tasks. Interpreters available with FreeBSD Here is a list of interpreters that are available as FreeBSD packages, with a brief discussion of some of the more popular interpreted languages. To get one of these packages, all you need to do is to click on the hotlink for the package, to download the package and then install the package by running: - &prompt.root; pkg_add package name + &prompt.root; pkg_add package name as root. Obviously, you will need to have a fully functional FreeBSD 2.1.0 or later system for the package to work! BASIC Short for Beginner's All-purpose Symbolic Instruction Code. Developed in the 1950s for teaching University students to program and provided with every self-respecting personal computer in the 1980s, BASIC has been the first programming language for many programmers. It is also the foundation for Visual Basic. The Bywater Basic Interpreter and the Phil Cockroft's Basic Interpreter (formerly Rabbit Basic) are available as FreeBSD packages. Lisp A language that was developed in the late 1950s as an alternative to the number-crunching languages that were popular at the time. Instead of being based on numbers, Lisp is based on lists; in fact the name is short for List Processing. Very popular in AI (Artificial Intelligence) circles. Lisp is an extremely powerful and sophisticated language, but can be rather large and unwieldy. Various implementations of Lisp that can run on UNIX systems are available as packages for FreeBSD. GNU Common Lisp, CLISP by Bruno Haible and Michael Stoll, CMUCL which includes a highly-optimizing compiler too, or simpler Lisp implementations, like SLisp which implements most of the Common Lisp constructs in a few hundred lines of C code. Perl Very popular with system administrators for writing scripts; also often used on World Wide Web servers for writing CGI scripts. Perl is available as a package for all FreeBSD releases, and is installed as /usr/bin/perl in the base system of 4.x releases. Scheme A dialect of Lisp that is rather more compact and cleaner than Common Lisp. Popular in Universities as it is simple enough to teach to undergraduates as a first language, while it has a high enough level of abstraction to be used in research work. FreeBSD has packages of the Elk Scheme Interpreter, the MIT Scheme Interpreter and the SCM Scheme Interpreter. Icon Icon is a high-level language with extensive facilities for processing strings and structures. A package is available for FreeBSD. Logo Logo is a language that is easy to learn, and has been used as an introductory programming language in various courses. It is an excellent tool to work with when teaching programming in small ages, as it makes the creation of elaborate geometric shapes an easy task even for very small children. A package is available for FreeBSD of Brian Harvey's LOGO Interpreter. Python Python is an Object-Oriented, interpreted language. Its advocates argue that it is one of the best languages to start programming with, since it is relatively easy to start with, but is not limited in comparison to other popular interpreted languages that are used for the development of large, complex applications (Perl and Tcl are two other languages that are popular for such tasks). A package of the latest version of Python for FreeBSD is available here. Tcl and Tk Tcl is an embeddable, interpreted language, that has become widely used and became popular mostly because of its portability to many platforms. It can be used both for quickly writing small, prototype applications, or (when combined with Tk, a GUI toolkit) fully-fledged, featureful programs. Various versions of Tcl are available as packages for FreeBSD. The latest version is, as of this writing, Tcl version 8.3. Compilers Compilers are rather different. First of all, you write your code in a file (or files) using an editor. You then run the compiler and see if it accepts your program. If it did not compile, grit your teeth and go back to the editor; if it did compile and gave you a program, you can run it either at a shell command prompt or in a debugger to see if it works properly. If you run it in the shell, you may get a core dump. Obviously, this is not quite as direct as using an interpreter. However it allows you to do a lot of things which are very difficult or even impossible with an interpreter, such as writing code which interacts closely with the operating system—or even writing your own operating system! It is also useful if you need to write very efficient code, as the compiler can take its time and optimize the code, which would not be acceptable in an interpreter. Moreover, distributing a program written for a compiler is usually more straightforward than one written for an interpreter—you can just give them a copy of the executable, assuming they have the same operating system as you. Compiled languages include Pascal, C and C++. C and C++ are rather unforgiving languages, and best suited to more experienced programmers; Pascal, on the other hand, was designed as an educational language, and is quite a good language to start with. FreeBSD does not include Pascal support in the base system, but the GNU Pascal Compiler (gpc) is available in the ports collection as lang/gpc. As the edit-compile-run-debug cycle is rather tedious when using separate programs, many commercial compiler makers have produced Integrated Development Environments (IDEs for short). FreeBSD does not include an IDE in the base system, but devel/kdevelop is available in the ports tree and many use Emacs for this purpose. Using Emacs as an IDE is discussed in . Compiling with <command>cc</command> This section deals only with the GNU compiler for C and C++, since that comes with the base FreeBSD system. It can be invoked by either cc or gcc. The details of producing a program with an interpreter vary considerably between interpreters, and are usually well covered in the documentation and on-line help for the interpreter. Once you have written your masterpiece, the next step is to convert it into something that will (hopefully!) run on FreeBSD. This usually involves several steps, each of which is done by a separate program. Pre-process your source code to remove comments and do other tricks like expanding macros in C. Check the syntax of your code to see if you have obeyed the rules of the language. If you have not, it will complain! Convert the source code into assembly language—this is very close to machine code, but still understandable by humans. Allegedly. To be strictly accurate, cc converts the source code into its own, machine-independent p-code instead of assembly language at this stage. Convert the assembly language into machine code—yep, we are talking bits and bytes, ones and zeros here. Check that you have used things like functions and global variables in a consistent way. For example, if you have called a non-existent function, it will complain. If you are trying to produce an executable from several source code files, work out how to fit them all together. Work out how to produce something that the system's run-time loader will be able to load into memory and run. Finally, write the executable on the filesystem. The word compiling is often used to refer to just steps 1 to 4—the others are referred to as linking. Sometimes step 1 is referred to as pre-processing and steps 3-4 as assembling. Fortunately, almost all this detail is hidden from you, as cc is a front end that manages calling all these programs with the right arguments for you; simply typing &prompt.user; cc foobar.c will cause foobar.c to be compiled by all the steps above. If you have more than one file to compile, just do something like &prompt.user; cc foo.c bar.c Note that the syntax checking is just that—checking the syntax. It will not check for any logical mistakes you may have made, like putting the program into an infinite loop, or using a bubble sort when you meant to use a binary sort. In case you did not know, a binary sort is an efficient way of sorting things into order and a bubble sort is not. There are lots and lots of options for cc, which are all in the manual page. Here are a few of the most important ones, with examples of how to use them. The output name of the file. If you do not use this option, cc will produce an executable called a.out. The reasons for this are buried in the mists of history. &prompt.user; cc foobar.c executable is a.out &prompt.user; cc -o foobar foobar.c executable is foobar Just compile the file, do not link it. Useful for toy programs where you just want to check the syntax, or if you are using a Makefile. &prompt.user; cc -c foobar.c This will produce an object file (not an executable) called foobar.o. This can be linked together with other object files into an executable. Create a debug version of the executable. This makes the compiler put information into the executable about which line of which source file corresponds to which function call. A debugger can use this information to show the source code as you step through the program, which is very useful; the disadvantage is that all this extra information makes the program much bigger. Normally, you compile with while you are developing a program and then compile a release version without when you are satisfied it works properly. &prompt.user; cc -g foobar.c This will produce a debug version of the program. Note, we did not use the flag to specify the executable name, so we will get an executable called a.out. Producing a debug version called foobar is left as an exercise for the reader! Create an optimized version of the executable. The compiler performs various clever tricks to try and produce an executable that runs faster than normal. You can add a number after the to specify a higher level of optimization, but this often exposes bugs in the compiler's optimizer. For instance, the version of cc that comes with the 2.1.0 release of FreeBSD is known to produce bad code with the option in some circumstances. Optimization is usually only turned on when compiling a release version. &prompt.user; cc -O -o foobar foobar.c This will produce an optimized version of foobar. The following three flags will force cc to check that your code complies to the relevant international standard, often referred to as the ANSI standard, though strictly speaking it is an ISO standard. Enable all the warnings which the authors of cc believe are worthwhile. Despite the name, it will not enable all the warnings cc is capable of. Turn off most, but not all, of the non-ANSI C features provided by cc. Despite the name, it does not guarantee strictly that your code will comply to the standard. Turn off all cc's non-ANSI C features. Without these flags, cc will allow you to use some of its non-standard extensions to the standard. Some of these are very useful, but will not work with other compilers—in fact, one of the main aims of the standard is to allow people to write code that will work with any compiler on any system. This is known as portable code. Generally, you should try to make your code as portable as possible, as otherwise you may have to completely rewrite the program later to get it to work somewhere else—and who knows what you may be using in a few years time? &prompt.user; cc -Wall -ansi -pedantic -o foobar foobar.c This will produce an executable foobar after checking foobar.c for standard compliance. Specify a function library to be used during when linking. The most common example of this is when compiling a program that uses some of the mathematical functions in C. Unlike most other platforms, these are in a separate library from the standard C one and you have to tell the compiler to add it. The rule is that if the library is called libsomething.a, you give cc the argument . For example, the math library is libm.a, so you give cc the argument . A common gotcha with the math library is that it has to be the last library on the command line. &prompt.user; cc -o foobar foobar.c -lm This will link the math library functions into foobar. If you are compiling C++ code, you need to add , or if you are using FreeBSD 2.2 or later, to the command line argument to link the C++ library functions. Alternatively, you can run c++ instead of cc, which does this for you. c++ can also be invoked as g++ on FreeBSD. &prompt.user; cc -o foobar foobar.cc -lg++ For FreeBSD 2.1.6 and earlier &prompt.user; cc -o foobar foobar.cc -lstdc++ For FreeBSD 2.2 and later &prompt.user; c++ -o foobar foobar.cc Each of these will both produce an executable foobar from the C++ source file foobar.cc. Note that, on Unix systems, C++ source files traditionally end in .C, .cxx or .cc, rather than the MS-DOS style .cpp (which was already used for something else). gcc used to rely on this to work out what kind of compiler to use on the source file; however, this restriction no longer applies, so you may now call your C++ files .cpp with impunity! Common <command>cc</command> Queries and Problems I am trying to write a program which uses the sin() function and I get an error like this. What does it mean? /var/tmp/cc0143941.o: Undefined symbol `_sin' referenced from text segment When using mathematical functions like sin(), you have to tell cc to link in the math library, like so: &prompt.user; cc -o foobar foobar.c -lm All right, I wrote this simple program to practice using . All it does is raise 2.1 to the power of 6. #include <stdio.h> int main() { float f; f = pow(2.1, 6); printf("2.1 ^ 6 = %f\n", f); return 0; } and I compiled it as: &prompt.user; cc temp.c -lm like you said I should, but I get this when I run it: &prompt.user; ./a.out 2.1 ^ 6 = 1023.000000 This is not the right answer! What is going on? When the compiler sees you call a function, it checks if it has already seen a prototype for it. If it has not, it assumes the function returns an int, which is definitely not what you want here. So how do I fix this? The prototypes for the mathematical functions are in math.h. If you include this file, the compiler will be able to find the prototype and it will stop doing strange things to your calculation! #include <math.h> #include <stdio.h> int main() { ... After recompiling it as you did before, run it: &prompt.user; ./a.out 2.1 ^ 6 = 85.766121 If you are using any of the mathematical functions, always include math.h and remember to link in the math library. I compiled a file called foobar.c and I cannot find an executable called foobar. Where's it gone? Remember, cc will call the executable a.out unless you tell it differently. Use the option: &prompt.user; cc -o foobar foobar.c OK, I have an executable called foobar, I can see it when I run ls, but when I type in foobar at the command prompt it tells me there is no such file. Why can it not find it? Unlike MS-DOS, Unix does not look in the current directory when it is trying to find out which executable you want it to run, unless you tell it to. Either type ./foobar, which means run the file called foobar in the current directory, or change your PATH environment variable so that it looks something like bin:/usr/bin:/usr/local/bin:. The dot at the end means look in the current directory if it is not in any of the others. I called my executable test, but nothing happens when I run it. What is going on? Most Unix systems have a program called test in /usr/bin and the shell is picking that one up before it gets to checking the current directory. Either type: &prompt.user; ./test or choose a better name for your program! I compiled my program and it seemed to run all right at first, then there was an error and it said something about core dumped. What does that mean? The name core dump dates back to the very early days of Unix, when the machines used core memory for storing data. Basically, if the program failed under certain conditions, the system would write the contents of core memory to disk in a file called core, which the programmer could then pore over to find out what went wrong. Fascinating stuff, but what I am supposed to do now? Use gdb to analyze the core (see ). When my program dumped core, it said something about a segmentation fault. What is that? This basically means that your program tried to perform some sort of illegal operation on memory; Unix is designed to protect the operating system and other programs from rogue programs. Common causes for this are: Trying to write to a NULL pointer, eg char *foo = NULL; strcpy(foo, "bang!"); Using a pointer that has not been initialized, eg char *foo; strcpy(foo, "bang!"); The pointer will have some random value that, with luck, will point into an area of memory that is not available to your program and the kernel will kill your program before it can do any damage. If you are unlucky, it will point somewhere inside your own program and corrupt one of your data structures, causing the program to fail mysteriously. Trying to access past the end of an array, eg int bar[20]; bar[27] = 6; Trying to store something in read-only memory, eg char *foo = "My string"; strcpy(foo, "bang!"); Unix compilers often put string literals like "My string" into read-only areas of memory. Doing naughty things with malloc() and free(), eg char bar[80]; free(bar); or char *foo = malloc(27); free(foo); free(foo); Making one of these mistakes will not always lead to an error, but they are always bad practice. Some systems and compilers are more tolerant than others, which is why programs that ran well on one system can crash when you try them on an another. Sometimes when I get a core dump it says bus error. It says in my Unix book that this means a hardware problem, but the computer still seems to be working. Is this true? No, fortunately not (unless of course you really do have a hardware problem…). This is usually another way of saying that you accessed memory in a way you should not have. This dumping core business sounds as though it could be quite useful, if I can make it happen when I want to. Can I do this, or do I have to wait until there is an error? Yes, just go to another console or xterm, do &prompt.user; ps to find out the process ID of your program, and do &prompt.user; kill -ABRT pid where pid is the process ID you looked up. This is useful if your program has got stuck in an infinite loop, for instance. If your program happens to trap SIGABRT, there are several other signals which have a similar effect. Alternatively, you can create a core dump from inside your program, by calling the abort() function. See the manual page of &man.abort.3; to learn more. If you want to create a core dump from outside your program, but do not want the process to terminate, you can use the gcore program. See the manual page of &man.gcore.1; for more information. Make What is <command>make</command>? When you are working on a simple program with only one or two source files, typing in &prompt.user; cc file1.c file2.c is not too bad, but it quickly becomes very tedious when there are several files—and it can take a while to compile, too. One way to get around this is to use object files and only recompile the source file if the source code has changed. So we could have something like: &prompt.user; cc file1.o file2.o … file37.c … if we had changed file37.c, but not any of the others, since the last time we compiled. This may speed up the compilation quite a bit, but does not solve the typing problem. Or we could write a shell script to solve the typing problem, but it would have to re-compile everything, making it very inefficient on a large project. What happens if we have hundreds of source files lying about? What if we are working in a team with other people who forget to tell us when they have changed one of their source files that we use? Perhaps we could put the two solutions together and write something like a shell script that would contain some kind of magic rule saying when a source file needs compiling. Now all we need now is a program that can understand these rules, as it is a bit too complicated for the shell. This program is called make. It reads in a file, called a makefile, that tells it how different files depend on each other, and works out which files need to be re-compiled and which ones do not. For example, a rule could say something like if fromboz.o is older than fromboz.c, that means someone must have changed fromboz.c, so it needs to be re-compiled. The makefile also has rules telling make how to re-compile the source file, making it a much more powerful tool. Makefiles are typically kept in the same directory as the source they apply to, and can be called makefile, Makefile or MAKEFILE. Most programmers use the name Makefile, as this puts it near the top of a directory listing, where it can easily be seen. They do not use the MAKEFILE form as block capitals are often used for documentation files like README. Example of using <command>make</command> Here is a very simple make file: foo: foo.c cc -o foo foo.c It consists of two lines, a dependency line and a creation line. The dependency line here consists of the name of the program (known as the target), followed by a colon, then whitespace, then the name of the source file. When make reads this line, it looks to see if foo exists; if it exists, it compares the time foo was last modified to the time foo.c was last modified. If foo does not exist, or is older than foo.c, it then looks at the creation line to find out what to do. In other words, this is the rule for working out when foo.c needs to be re-compiled. The creation line starts with a tab (press the tab key) and then the command you would type to create foo if you were doing it at a command prompt. If foo is out of date, or does not exist, make then executes this command to create it. In other words, this is the rule which tells make how to re-compile foo.c. So, when you type make, it will make sure that foo is up to date with respect to your latest changes to foo.c. This principle can be extended to Makefiles with hundreds of targets—in fact, on FreeBSD, it is possible to compile the entire operating system just by typing make world in the appropriate directory! Another useful property of makefiles is that the targets do not have to be programs. For instance, we could have a make file that looks like this: foo: foo.c cc -o foo foo.c install: cp foo /home/me We can tell make which target we want to make by typing: &prompt.user; make target make will then only look at that target and ignore any others. For example, if we type make foo with the makefile above, make will ignore the install target. If we just type make on its own, make will always look at the first target and then stop without looking at any others. So if we typed make here, it will just go to the foo target, re-compile foo if necessary, and then stop without going on to the install target. Notice that the install target does not actually depend on anything! This means that the command on the following line is always executed when we try to make that target by typing make install. In this case, it will copy foo into the user's home directory. This is often used by application makefiles, so that the application can be installed in the correct directory when it has been correctly compiled. This is a slightly confusing subject to try to explain. If you do not quite understand how make works, the best thing to do is to write a simple program like hello world and a make file like the one above and experiment. Then progress to using more than one source file, or having the source file include a header file. The touch command is very useful here—it changes the date on a file without you having to edit it. Make and include-files C code often starts with a list of files to include, for example stdio.h. Some of these files are system-include files, some of them are from the project you are now working on: #include <stdio.h> #include "foo.h" int main(.... To make sure that this file is recompiled the moment foo.h is changed, you have to add it in your Makefile: foo: foo.c foo.h The moment your project is getting bigger and you have more and more own include-files to maintain, it will be a pain to keep track of all include files and the files which are depending on it. If you change an include-file but forget to recompile all the files which are depending on it, the results will be devastating. gcc has an option to analyze your files and to produce a list of include-files and their dependencies: . If you add this to your Makefile: depend: gcc -E -MM *.c > .depend and run make depend, the file .depend will appear with a list of object-files, C-files and the include-files: foo.o: foo.c foo.h If you change foo.h, next time you run make all files depending on foo.h will be recompiled. Do not forget to run make depend each time you add an include-file to one of your files. FreeBSD Makefiles Makefiles can be rather complicated to write. Fortunately, BSD-based systems like FreeBSD come with some very powerful ones as part of the system. One very good example of this is the FreeBSD ports system. Here is the essential part of a typical ports Makefile: MASTER_SITES= ftp://freefall.cdrom.com/pub/FreeBSD/LOCAL_PORTS/ DISTFILES= scheme-microcode+dist-7.3-freebsd.tgz .include <bsd.port.mk> Now, if we go to the directory for this port and type make, the following happens: A check is made to see if the source code for this port is already on the system. If it is not, an FTP connection to the URL in MASTER_SITES is set up to download the source. The checksum for the source is calculated and compared it with one for a known, good, copy of the source. This is to make sure that the source was not corrupted while in transit. Any changes required to make the source work on FreeBSD are applied—this is known as patching. Any special configuration needed for the source is done. (Many Unix program distributions try to work out which version of Unix they are being compiled on and which optional Unix features are present—this is where they are given the information in the FreeBSD ports scenario). The source code for the program is compiled. In effect, we change to the directory where the source was unpacked and do make—the program's own make file has the necessary information to build the program. We now have a compiled version of the program. If we wish, we can test it now; when we feel confident about the program, we can type make install. This will cause the program and any supporting files it needs to be copied into the correct location; an entry is also made into a package database, so that the port can easily be uninstalled later if we change our mind about it. Now I think you will agree that is rather impressive for a four line script! The secret lies in the last line, which tells make to look in the system makefile called bsd.port.mk. It is easy to overlook this line, but this is where all the clever stuff comes from—someone has written a makefile that tells make to do all the things above (plus a couple of other things I did not mention, including handling any errors that may occur) and anyone can get access to that just by putting a single line in their own make file! If you want to have a look at these system makefiles, they are in /usr/share/mk, but it is probably best to wait until you have had a bit of practice with makefiles, as they are very complicated (and if you do look at them, make sure you have a flask of strong coffee handy!) More advanced uses of <command>make</command> Make is a very powerful tool, and can do much more than the simple example above shows. Unfortunately, there are several different versions of make, and they all differ considerably. The best way to learn what they can do is probably to read the documentation—hopefully this introduction will have given you a base from which you can do this. The version of make that comes with FreeBSD is the Berkeley make; there is a tutorial for it in /usr/share/doc/psd/12.make. To view it, do &prompt.user; zmore paper.ascii.gz in that directory. Many applications in the ports use GNU make, which has a very good set of info pages. If you have installed any of these ports, GNU make will automatically have been installed as gmake. It is also available as a port and package in its own right. To view the info pages for GNU make, you will have to edit the dir file in the /usr/local/info directory to add an entry for it. This involves adding a line like * Make: (make). The GNU Make utility. to the file. Once you have done this, you can type info and then select make from the menu (or in Emacs, do C-h i). Debugging The Debugger The debugger that comes with FreeBSD is called gdb (GNU debugger). You start it up by typing &prompt.user; gdb progname although most people prefer to run it inside Emacs. You can do this by: M-x gdb RET progname RET Using a debugger allows you to run the program under more controlled circumstances. Typically, you can step through the program a line at a time, inspect the value of variables, change them, tell the debugger to run up to a certain point and then stop, and so on. You can even attach to a program that is already running, or load a core file to investigate why the program crashed. It is even possible to debug the kernel, though that is a little trickier than the user applications we will be discussing in this section. gdb has quite good on-line help, as well as a set of info pages, so this section will concentrate on a few of the basic commands. Finally, if you find its text-based command-prompt style off-putting, there is a graphical front-end for it (xxgdb) in the ports collection. This section is intended to be an introduction to using gdb and does not cover specialized topics such as debugging the kernel. Running a program in the debugger You will need to have compiled the program with the option to get the most out of using gdb. It will work without, but you will only see the name of the function you are in, instead of the source code. If you see a line like: … (no debugging symbols found) … when gdb starts up, you will know that the program was not compiled with the option. At the gdb prompt, type break main. This will tell the debugger to skip over the preliminary set-up code in the program and start at the beginning of your code. Now type run to start the program—it will start at the beginning of the set-up code and then get stopped by the debugger when it calls main(). (If you have ever wondered where main() gets called from, now you know!). You can now step through the program, a line at a time, by pressing n. If you get to a function call, you can step into it by pressing s. Once you are in a function call, you can return from stepping into a function call by pressing f. You can also use up and down to take a quick look at the caller. Here is a simple example of how to spot a mistake in a program with gdb. This is our program (with a deliberate mistake): #include <stdio.h> int bazz(int anint); main() { int i; printf("This is my program\n"); bazz(i); return 0; } int bazz(int anint) { printf("You gave me %d\n", anint); return anint; } This program sets i to be 5 and passes it to a function bazz() which prints out the number we gave it. When we compile and run the program we get &prompt.user; cc -g -o temp temp.c &prompt.user; ./temp This is my program anint = 4231 That was not what we expected! Time to see what is going on! &prompt.user; gdb temp GDB is free software and you are welcome to distribute copies of it under certain conditions; type "show copying" to see the conditions. There is absolutely no warranty for GDB; type "show warranty" for details. GDB 4.13 (i386-unknown-freebsd), Copyright 1994 Free Software Foundation, Inc. (gdb) break main Skip the set-up code Breakpoint 1 at 0x160f: file temp.c, line 9. gdb puts breakpoint at main() (gdb) run Run as far as main() Starting program: /home/james/tmp/temp Program starts running Breakpoint 1, main () at temp.c:9 gdb stops at main() (gdb) n Go to next line This is my program Program prints out (gdb) s step into bazz() bazz (anint=4231) at temp.c:17 gdb displays stack frame (gdb) Hang on a minute! How did anint get to be 4231? Did we not we set it to be 5 in main()? Let's move up to main() and have a look. (gdb) up Move up call stack #1 0x1625 in main () at temp.c:11 gdb displays stack frame (gdb) p i Show us the value of i $1 = 4231 gdb displays 4231 Oh dear! Looking at the code, we forgot to initialize i. We meant to put … main() { int i; i = 5; printf("This is my program\n"); … but we left the i=5; line out. As we did not initialize i, it had whatever number happened to be in that area of memory when the program ran, which in this case happened to be 4231. gdb displays the stack frame every time we go into or out of a function, even if we are using up and down to move around the call stack. This shows the name of the function and the values of its arguments, which helps us keep track of where we are and what is going on. (The stack is a storage area where the program stores information about the arguments passed to functions and where to go when it returns from a function call). Examining a core file A core file is basically a file which contains the complete state of the process when it crashed. In the good old days, programmers had to print out hex listings of core files and sweat over machine code manuals, but now life is a bit easier. Incidentally, under FreeBSD and other 4.4BSD systems, a core file is called progname.core instead of just core, to make it clearer which program a core file belongs to. To examine a core file, start up gdb in the usual way. Instead of typing break or run, type (gdb) core progname.core If you are not in the same directory as the core file, you will have to do dir /path/to/core/file first. You should see something like this: &prompt.user; gdb a.out GDB is free software and you are welcome to distribute copies of it under certain conditions; type "show copying" to see the conditions. There is absolutely no warranty for GDB; type "show warranty" for details. GDB 4.13 (i386-unknown-freebsd), Copyright 1994 Free Software Foundation, Inc. (gdb) core a.out.core Core was generated by `a.out'. Program terminated with signal 11, Segmentation fault. Cannot access memory at address 0x7020796d. #0 0x164a in bazz (anint=0x5) at temp.c:17 (gdb) In this case, the program was called a.out, so the core file is called a.out.core. We can see that the program crashed due to trying to access an area in memory that was not available to it in a function called bazz. Sometimes it is useful to be able to see how a function was called, as the problem could have occurred a long way up the call stack in a complex program. The bt command causes gdb to print out a back-trace of the call stack: (gdb) bt #0 0x164a in bazz (anint=0x5) at temp.c:17 #1 0xefbfd888 in end () #2 0x162c in main () at temp.c:11 (gdb) The end() function is called when a program crashes; in this case, the bazz() function was called from main(). Attaching to a running program One of the neatest features about gdb is that it can attach to a program that is already running. Of course, that assumes you have sufficient permissions to do so. A common problem is when you are stepping through a program that forks, and you want to trace the child, but the debugger will only let you trace the parent. What you do is start up another gdb, use ps to find the process ID for the child, and do (gdb) attach pid in gdb, and then debug as usual. That is all very well, you are probably thinking, but by the time I have done that, the child process will be over the hill and far away. Fear not, gentle reader, here is how to do it (courtesy of the gdb info pages): … if ((pid = fork()) < 0) /* _Always_ check this */ error(); else if (pid == 0) { /* child */ int PauseMode = 1; while (PauseMode) sleep(10); /* Wait until someone attaches to us */ … } else { /* parent */ … Now all you have to do is attach to the child, set PauseMode to 0, and wait for the sleep() call to return! Using Emacs as a Development Environment Emacs Unfortunately, Unix systems do not come with the kind of everything-you-ever-wanted-and-lots-more-you-did-not-in-one-gigantic-package integrated development environments that other systems have. Some powerful, free IDEs now exist, such as KDevelop in the ports collection. However, it is possible to set up your own environment. It may not be as pretty, and it may not be quite as integrated, but you can set it up the way you want it. And it is free. And you have the source to it. The key to it all is Emacs. Now there are some people who loathe it, but many who love it. If you are one of the former, I am afraid this section will hold little of interest to you. Also, you will need a fair amount of memory to run it—I would recommend 8MB in text mode and 16MB in X as the bare minimum to get reasonable performance. Emacs is basically a highly customizable editor—indeed, it has been customized to the point where it is more like an operating system than an editor! Many developers and sysadmins do in fact spend practically all their time working inside Emacs, leaving it only to log out. It is impossible even to summarize everything Emacs can do here, but here are some of the features of interest to developers: Very powerful editor, allowing search-and-replace on both strings and regular expressions (patterns), jumping to start/end of block expression, etc, etc. Pull-down menus and online help. Language-dependent syntax highlighting and indentation. Completely customizable. You can compile and debug programs within Emacs. On a compilation error, you can jump to the offending line of source code. Friendly-ish front-end to the info program used for reading GNU hypertext documentation, including the documentation on Emacs itself. Friendly front-end to gdb, allowing you to look at the source code as you step through your program. You can read Usenet news and mail while your program is compiling. And doubtless many more that I have overlooked. Emacs can be installed on FreeBSD using the Emacs port. Once it is installed, start it up and do C-h t to read an Emacs tutorial—that means hold down the control key, press h, let go of the control key, and then press t. (Alternatively, you can you use the mouse to select Emacs Tutorial from the Help menu). Although Emacs does have menus, it is well worth learning the key bindings, as it is much quicker when you are editing something to press a couple of keys than to try and find the mouse and then click on the right place. And, when you are talking to seasoned Emacs users, you will find they often casually throw around expressions like M-x replace-s RET foo RET bar RET so it is useful to know what they mean. And in any case, Emacs has far too many useful functions for them to all fit on the menu bars. Fortunately, it is quite easy to pick up the key-bindings, as they are displayed next to the menu item. My advice is to use the menu item for, say, opening a file until you understand how it works and feel confident with it, then try doing C-x C-f. When you are happy with that, move on to another menu command. If you can not remember what a particular combination of keys does, select Describe Key from the Help menu and type it in—Emacs will tell you what it does. You can also use the Command Apropos menu item to find out all the commands which contain a particular word in them, with the key binding next to it. By the way, the expression above means hold down the Meta key, press x, release the Meta key, type replace-s (short for replace-string—another feature of Emacs is that you can abbreviate commands), press the return key, type foo (the string you want replaced), press the return key, type bar (the string you want to replace foo with) and press return again. Emacs will then do the search-and-replace operation you have just requested. If you are wondering what on earth the Meta key is, it is a special key that many Unix workstations have. Unfortunately, PC's do not have one, so it is usually the alt key (or if you are unlucky, the escape key). Oh, and to get out of Emacs, do C-x C-c (that means hold down the control key, press x, press c and release the control key). If you have any unsaved files open, Emacs will ask you if you want to save them. (Ignore the bit in the documentation where it says C-z is the usual way to leave Emacs—that leaves Emacs hanging around in the background, and is only really useful if you are on a system which does not have virtual terminals). Configuring Emacs Emacs does many wonderful things; some of them are built in, some of them need to be configured. Instead of using a proprietary macro language for configuration, Emacs uses a version of Lisp specially adapted for editors, known as Emacs Lisp. Working with Emacs Lisp can be quite helpful if you want to go on and learn something like Common Lisp. Emacs Lisp has many features of Common Lisp, although it is considerably smaller (and thus easier to master). The best way to learn Emacs Lisp is to download the Emacs Tutorial However, there is no need to actually know any Lisp to get started with configuring Emacs, as I have included a sample .emacs file, which should be enough to get you started. Just copy it into your home directory and restart Emacs if it is already running; it will read the commands from the file and (hopefully) give you a useful basic setup. A sample <filename>.emacs</filename> file Unfortunately, there is far too much here to explain it in detail; however there are one or two points worth mentioning. Everything beginning with a ; is a comment and is ignored by Emacs. In the first line, the -*- Emacs-Lisp -*- is so that we can edit the .emacs file itself within Emacs and get all the fancy features for editing Emacs Lisp. Emacs usually tries to guess this based on the filename, and may not get it right for .emacs. The tab key is bound to an indentation function in some modes, so when you press the tab key, it will indent the current line of code. If you want to put a tab character in whatever you are writing, hold the control key down while you are pressing the tab key. This file supports syntax highlighting for C, C++, Perl, Lisp and Scheme, by guessing the language from the filename. Emacs already has a pre-defined function called next-error. In a compilation output window, this allows you to move from one compilation error to the next by doing M-n; we define a complementary function, previous-error, that allows you to go to a previous error by doing M-p. The nicest feature of all is that C-c C-c will open up the source file in which the error occurred and jump to the appropriate line. We enable Emacs's ability to act as a server, so that if you are doing something outside Emacs and you want to edit a file, you can just type in &prompt.user; emacsclient filename and then you can edit the file in your Emacs! Many Emacs users set their EDITOR environment to emacsclient so this happens every time they need to edit a file. A sample <filename>.emacs</filename> file ;; -*-Emacs-Lisp-*- ;; This file is designed to be re-evaled; use the variable first-time ;; to avoid any problems with this. (defvar first-time t "Flag signifying this is the first time that .emacs has been evaled") ;; Meta (global-set-key "\M- " 'set-mark-command) (global-set-key "\M-\C-h" 'backward-kill-word) (global-set-key "\M-\C-r" 'query-replace) (global-set-key "\M-r" 'replace-string) (global-set-key "\M-g" 'goto-line) (global-set-key "\M-h" 'help-command) ;; Function keys (global-set-key [f1] 'manual-entry) (global-set-key [f2] 'info) (global-set-key [f3] 'repeat-complex-command) (global-set-key [f4] 'advertised-undo) (global-set-key [f5] 'eval-current-buffer) (global-set-key [f6] 'buffer-menu) (global-set-key [f7] 'other-window) (global-set-key [f8] 'find-file) (global-set-key [f9] 'save-buffer) (global-set-key [f10] 'next-error) (global-set-key [f11] 'compile) (global-set-key [f12] 'grep) (global-set-key [C-f1] 'compile) (global-set-key [C-f2] 'grep) (global-set-key [C-f3] 'next-error) (global-set-key [C-f4] 'previous-error) (global-set-key [C-f5] 'display-faces) (global-set-key [C-f8] 'dired) (global-set-key [C-f10] 'kill-compilation) ;; Keypad bindings (global-set-key [up] "\C-p") (global-set-key [down] "\C-n") (global-set-key [left] "\C-b") (global-set-key [right] "\C-f") (global-set-key [home] "\C-a") (global-set-key [end] "\C-e") (global-set-key [prior] "\M-v") (global-set-key [next] "\C-v") (global-set-key [C-up] "\M-\C-b") (global-set-key [C-down] "\M-\C-f") (global-set-key [C-left] "\M-b") (global-set-key [C-right] "\M-f") (global-set-key [C-home] "\M-<") (global-set-key [C-end] "\M->") (global-set-key [C-prior] "\M-<") (global-set-key [C-next] "\M->") ;; Mouse (global-set-key [mouse-3] 'imenu) ;; Misc (global-set-key [C-tab] "\C-q\t") ; Control tab quotes a tab. (setq backup-by-copying-when-mismatch t) ;; Treat 'y' or <CR> as yes, 'n' as no. (fset 'yes-or-no-p 'y-or-n-p) (define-key query-replace-map [return] 'act) (define-key query-replace-map [?\C-m] 'act) ;; Load packages (require 'desktop) (require 'tar-mode) ;; Pretty diff mode (autoload 'ediff-buffers "ediff" "Intelligent Emacs interface to diff" t) (autoload 'ediff-files "ediff" "Intelligent Emacs interface to diff" t) (autoload 'ediff-files-remote "ediff" "Intelligent Emacs interface to diff") (if first-time (setq auto-mode-alist (append '(("\\.cpp$" . c++-mode) ("\\.hpp$" . c++-mode) ("\\.lsp$" . lisp-mode) ("\\.scm$" . scheme-mode) ("\\.pl$" . perl-mode) ) auto-mode-alist))) ;; Auto font lock mode (defvar font-lock-auto-mode-list (list 'c-mode 'c++-mode 'c++-c-mode 'emacs-lisp-mode 'lisp-mode 'perl-mode 'scheme-mode) "List of modes to always start in font-lock-mode") (defvar font-lock-mode-keyword-alist '((c++-c-mode . c-font-lock-keywords) (perl-mode . perl-font-lock-keywords)) "Associations between modes and keywords") (defun font-lock-auto-mode-select () "Automatically select font-lock-mode if the current major mode is in font-lock-auto-mode-list" (if (memq major-mode font-lock-auto-mode-list) (progn (font-lock-mode t)) ) ) (global-set-key [M-f1] 'font-lock-fontify-buffer) ;; New dabbrev stuff ;(require 'new-dabbrev) (setq dabbrev-always-check-other-buffers t) (setq dabbrev-abbrev-char-regexp "\\sw\\|\\s_") (add-hook 'emacs-lisp-mode-hook '(lambda () (set (make-local-variable 'dabbrev-case-fold-search) nil) (set (make-local-variable 'dabbrev-case-replace) nil))) (add-hook 'c-mode-hook '(lambda () (set (make-local-variable 'dabbrev-case-fold-search) nil) (set (make-local-variable 'dabbrev-case-replace) nil))) (add-hook 'text-mode-hook '(lambda () (set (make-local-variable 'dabbrev-case-fold-search) t) (set (make-local-variable 'dabbrev-case-replace) t))) ;; C++ and C mode... (defun my-c++-mode-hook () (setq tab-width 4) (define-key c++-mode-map "\C-m" 'reindent-then-newline-and-indent) (define-key c++-mode-map "\C-ce" 'c-comment-edit) (setq c++-auto-hungry-initial-state 'none) (setq c++-delete-function 'backward-delete-char) (setq c++-tab-always-indent t) (setq c-indent-level 4) (setq c-continued-statement-offset 4) (setq c++-empty-arglist-indent 4)) (defun my-c-mode-hook () (setq tab-width 4) (define-key c-mode-map "\C-m" 'reindent-then-newline-and-indent) (define-key c-mode-map "\C-ce" 'c-comment-edit) (setq c-auto-hungry-initial-state 'none) (setq c-delete-function 'backward-delete-char) (setq c-tab-always-indent t) ;; BSD-ish indentation style (setq c-indent-level 4) (setq c-continued-statement-offset 4) (setq c-brace-offset -4) (setq c-argdecl-indent 0) (setq c-label-offset -4)) ;; Perl mode (defun my-perl-mode-hook () (setq tab-width 4) (define-key c++-mode-map "\C-m" 'reindent-then-newline-and-indent) (setq perl-indent-level 4) (setq perl-continued-statement-offset 4)) ;; Scheme mode... (defun my-scheme-mode-hook () (define-key scheme-mode-map "\C-m" 'reindent-then-newline-and-indent)) ;; Emacs-Lisp mode... (defun my-lisp-mode-hook () (define-key lisp-mode-map "\C-m" 'reindent-then-newline-and-indent) (define-key lisp-mode-map "\C-i" 'lisp-indent-line) (define-key lisp-mode-map "\C-j" 'eval-print-last-sexp)) ;; Add all of the hooks... (add-hook 'c++-mode-hook 'my-c++-mode-hook) (add-hook 'c-mode-hook 'my-c-mode-hook) (add-hook 'scheme-mode-hook 'my-scheme-mode-hook) (add-hook 'emacs-lisp-mode-hook 'my-lisp-mode-hook) (add-hook 'lisp-mode-hook 'my-lisp-mode-hook) (add-hook 'perl-mode-hook 'my-perl-mode-hook) ;; Complement to next-error (defun previous-error (n) "Visit previous compilation error message and corresponding source code." (interactive "p") (next-error (- n))) ;; Misc... (transient-mark-mode 1) (setq mark-even-if-inactive t) (setq visible-bell nil) (setq next-line-add-newlines nil) (setq compile-command "make") (setq suggest-key-bindings nil) (put 'eval-expression 'disabled nil) (put 'narrow-to-region 'disabled nil) (put 'set-goal-column 'disabled nil) (if (>= emacs-major-version 21) (setq show-trailing-whitespace t)) ;; Elisp archive searching (autoload 'format-lisp-code-directory "lispdir" nil t) (autoload 'lisp-dir-apropos "lispdir" nil t) (autoload 'lisp-dir-retrieve "lispdir" nil t) (autoload 'lisp-dir-verify "lispdir" nil t) ;; Font lock mode (defun my-make-face (face color &optional bold) "Create a face from a color and optionally make it bold" (make-face face) (copy-face 'default face) (set-face-foreground face color) (if bold (make-face-bold face)) ) (if (eq window-system 'x) (progn (my-make-face 'blue "blue") (my-make-face 'red "red") (my-make-face 'green "dark green") (setq font-lock-comment-face 'blue) (setq font-lock-string-face 'bold) (setq font-lock-type-face 'bold) (setq font-lock-keyword-face 'bold) (setq font-lock-function-name-face 'red) (setq font-lock-doc-string-face 'green) (add-hook 'find-file-hooks 'font-lock-auto-mode-select) (setq baud-rate 1000000) (global-set-key "\C-cmm" 'menu-bar-mode) (global-set-key "\C-cms" 'scroll-bar-mode) (global-set-key [backspace] 'backward-delete-char) ; (global-set-key [delete] 'delete-char) (standard-display-european t) (load-library "iso-transl"))) ;; X11 or PC using direct screen writes (if window-system (progn ;; (global-set-key [M-f1] 'hilit-repaint-command) ;; (global-set-key [M-f2] [?\C-u M-f1]) (setq hilit-mode-enable-list '(not text-mode c-mode c++-mode emacs-lisp-mode lisp-mode scheme-mode) hilit-auto-highlight nil hilit-auto-rehighlight 'visible hilit-inhibit-hooks nil hilit-inhibit-rebinding t) (require 'hilit19) (require 'paren)) (setq baud-rate 2400) ; For slow serial connections ) ;; TTY type terminal (if (and (not window-system) (not (equal system-type 'ms-dos))) (progn (if first-time (progn (keyboard-translate ?\C-h ?\C-?) (keyboard-translate ?\C-? ?\C-h))))) ;; Under UNIX (if (not (equal system-type 'ms-dos)) (progn (if first-time (server-start)))) ;; Add any face changes here (add-hook 'term-setup-hook 'my-term-setup-hook) (defun my-term-setup-hook () (if (eq window-system 'pc) (progn ;; (set-face-background 'default "red") ))) ;; Restore the "desktop" - do this as late as possible (if first-time (progn (desktop-load-default) (desktop-read))) ;; Indicate that this file has been read at least once (setq first-time nil) ;; No need to debug anything now (setq debug-on-error nil) ;; All done (message "All done, %s%s" (user-login-name) ".") Extending the Range of Languages Emacs Understands Now, this is all very well if you only want to program in the languages already catered for in the .emacs file (C, C++, Perl, Lisp and Scheme), but what happens if a new language called whizbang comes out, full of exciting features? The first thing to do is find out if whizbang comes with any files that tell Emacs about the language. These usually end in .el, short for Emacs Lisp. For example, if whizbang is a FreeBSD port, we can locate these files by doing &prompt.user; find /usr/ports/lang/whizbang -name "*.el" -print and install them by copying them into the Emacs site Lisp directory. On FreeBSD 2.1.0-RELEASE, this is /usr/local/share/emacs/site-lisp. So for example, if the output from the find command was /usr/ports/lang/whizbang/work/misc/whizbang.el we would do &prompt.root; cp /usr/ports/lang/whizbang/work/misc/whizbang.el /usr/local/share/emacs/site-lisp Next, we need to decide what extension whizbang source files have. Let's say for the sake of argument that they all end in .wiz. We need to add an entry to our .emacs file to make sure Emacs will be able to use the information in whizbang.el. Find the auto-mode-alist entry in .emacs and add a line for whizbang, such as: … ("\\.lsp$" . lisp-mode) ("\\.wiz$" . whizbang-mode) ("\\.scm$" . scheme-mode) … This means that Emacs will automatically go into whizbang-mode when you edit a file ending in .wiz. Just below this, you will find the font-lock-auto-mode-list entry. Add whizbang-mode to it like so: ;; Auto font lock mode (defvar font-lock-auto-mode-list (list 'c-mode 'c++-mode 'c++-c-mode 'emacs-lisp-mode 'whizbang-mode 'lisp-mode 'perl-mode 'scheme-mode) "List of modes to always start in font-lock-mode") This means that Emacs will always enable font-lock-mode (ie syntax highlighting) when editing a .wiz file. And that is all that is needed. If there is anything else you want done automatically when you open up a .wiz file, you can add a whizbang-mode hook (see my-scheme-mode-hook for a simple example that adds auto-indent). Further Reading Brian Harvey and Matthew Wright Simply Scheme MIT 1994. ISBN 0-262-08226-8 Randall Schwartz Learning Perl O'Reilly 1993 ISBN 1-56592-042-2 Patrick Henry Winston and Berthold Klaus Paul Horn Lisp (3rd Edition) Addison-Wesley 1989 ISBN 0-201-08319-1 Brian W. Kernighan and Rob Pike The Unix Programming Environment Prentice-Hall 1984 ISBN 0-13-937681-X Brian W. Kernighan and Dennis M. Ritchie The C Programming Language (2nd Edition) Prentice-Hall 1988 ISBN 0-13-110362-8 Bjarne Stroustrup The C++ Programming Language Addison-Wesley 1991 ISBN 0-201-53992-6 W. Richard Stevens Advanced Programming in the Unix Environment Addison-Wesley 1992 ISBN 0-201-56317-7 W. Richard Stevens Unix Network Programming Prentice-Hall 1990 ISBN 0-13-949876-1 diff --git a/en_US.ISO8859-1/books/faq/book.sgml b/en_US.ISO8859-1/books/faq/book.sgml index 9a5b35d593..9f20467750 100644 --- a/en_US.ISO8859-1/books/faq/book.sgml +++ b/en_US.ISO8859-1/books/faq/book.sgml @@ -1,12175 +1,12175 @@ %man; %freebsd; %authors; %teams; %bookinfo; %mailing-lists; ]> Frequently Asked Questions for FreeBSD 2.X, 3.X and 4.X The FreeBSD Documentation Project $FreeBSD$ 1995 1996 1997 1998 1999 2000 2001 2002 2003 The FreeBSD Documentation Project &bookinfo.trademarks; &bookinfo.legalnotice; This is the FAQ for FreeBSD versions 2.X, 3.X, and 4.X. All entries are assumed to be relevant to FreeBSD 2.0.5 and later, unless otherwise noted. If you are interested in helping with this project, send email to the &a.doc;. The latest version of this document is always available from the FreeBSD World Wide Web server. It may also be downloaded as one large HTML file with HTTP or as plain text, PostScript, PDF, etc. from the FreeBSD FTP server. You may also want to Search the FAQ. Introduction Welcome to the FreeBSD 2.X-4.X FAQ! As is usual with Usenet FAQs, this document aims to cover the most frequently asked questions concerning the FreeBSD operating system (and of course answer them!). Although originally intended to reduce bandwidth and avoid the same old questions being asked over and over again, FAQs have become recognized as valuable information resources. Every effort has been made to make this FAQ as informative as possible; if you have any suggestions as to how it may be improved, please feel free to mail them to the &a.doc;. What is FreeBSD? Briefly, FreeBSD is a UN*X-like operating system for the i386, IA-64, PC-98, Alpha/AXP, and UltraSPARC platforms based on U.C. Berkeley's 4.4BSD-Lite release, with some 4.4BSD-Lite2 enhancements. It is also based indirectly on William Jolitz's port of U.C. Berkeley's Net/2 to the i386, known as 386BSD, though very little of the 386BSD code remains. A fuller description of what FreeBSD is and how it can work for you may be found on the FreeBSD home page. FreeBSD is used by companies, Internet Service Providers, researchers, computer professionals, students and home users all over the world in their work, education and recreation. See some of them in the FreeBSD Gallery. For more detailed information on FreeBSD, please see the FreeBSD Handbook. What is the goal of the FreeBSD Project? The goal of the FreeBSD Project is to provide software that may be used for any purpose and without strings attached. Many of us have a significant investment in the code (and project) and would certainly not mind a little financial compensation now and then, but we definitely do not insist on it. We believe that our first and foremost mission is to provide code to any and all comers, and for whatever purpose, so that the code gets the widest possible use and provides the widest possible benefit. This is, we believe, one of the most fundamental goals of Free Software and one that we enthusiastically support. That code in our source tree which falls under the GNU General Public License (GPL) or GNU Library General Public License (LGPL) comes with slightly more strings attached, though at least on the side of enforced access rather than the usual opposite. Due to the additional complexities that can evolve in the commercial use of GPL software, we do, however, endeavor to replace such software with submissions under the more relaxed FreeBSD license whenever possible. Does the FreeBSD license have any restrictions? Yes. Those restrictions do not control how you use the code, merely how you treat the FreeBSD Project itself. If you have serious license concerns, read the actual license. For the simply curious, the license can be summarized like this. Do not claim that you wrote this. Do not sue us if it breaks. Can FreeBSD replace my current operating system? For most people, yes. But this question is not quite that cut-and-dried. Most people do not actually use an operating system. They use applications. The applications are what really use the operating system. FreeBSD is designed to provide a robust and full-featured environment for applications. It supports a wide variety of web browsers, office suites, email readers, graphics programs, programming environments, network servers, and just about everything else you might want. Most of these applications can be managed through the Ports Collection. If you need to use an application that is only available on one operating system, you simply cannot replace that operating system. Chances are there is a very similar application on FreeBSD, however. If you want a solid office or Internet server, a reliable workstation, or just the ability to do your job without interruptions, FreeBSD will almost certainly do everything you need. Many computer users across the world, including both novices and experienced &unix; administrators, use FreeBSD as their only desktop operating system. If you are migrating to FreeBSD from some other &unix; environment, you already know most of what you need to. If your background is in graphic-driven operating systems such as Windows and older versions of Mac OS, expect to invest additional time learning the &unix; way of doing things. This FAQ and the FreeBSD Handbook are excellent places to start. Why is it called FreeBSD? It may be used free of charge, even by commercial users. Full source for the operating system is freely available, and the minimum possible restrictions have been placed upon its use, distribution and incorporation into other work (commercial or non-commercial). Anyone who has an improvement or bug fix is free to submit their code and have it added to the source tree (subject to one or two obvious provisions). It is worth pointing out that the word free is being used in two ways here, one meaning at no cost, the other meaning you can do whatever you like. Apart from one or two things you cannot do with the FreeBSD code, for example pretending you wrote it, you can really do whatever you like with it. What are the differences between FreeBSD and NetBSD, OpenBSD, and other open source BSD operating systems? James Howard wrote a good explanation of the history and differences between the various projects for DaemonNews, called The BSD Family Tree which goes a fair way to answering this question. What is the latest version of FreeBSD? At this point in FreeBSD's development, there are two parallel development branches; releases are being made from both branches. The 4.X series of releases is being made from the -STABLE branch and the 5.X series of releases is being made from -CURRENT. Version &rel.current; is the latest release from the -CURRENT branch; it was released in &rel.current.date;. Version &rel2.current; is the latest release from the -STABLE branch; it was released in &rel2.current.date;. Briefly, -STABLE is aimed at the ISP, corporate user, or any user who wants stability and a minimal number of changes compared to the new (and possibly unstable) features of the latest -CURRENT snapshot. Releases can come from either branch, but -CURRENT should only be used if you are prepared for its increased volatility (relative to -STABLE, that is). Releases are made every few months. While many people stay more up-to-date with the FreeBSD sources (see the questions on FreeBSD-CURRENT and FreeBSD-STABLE) than that, doing so is more of a commitment, as the sources are a moving target. More information on FreeBSD releases can be found on the Release Engineering page on the FreeBSD Web site. What is FreeBSD-CURRENT? FreeBSD-CURRENT is the development version of the operating system, which will in due course become the new &os.stable; branch. This is expected to happen around 5.2-RELEASE. As such, it is really only of interest to developers working on the system and die-hard hobbyists. See the relevant section in the handbook for details on running -CURRENT. If you are not familiar with the operating system or are not capable of identifying the difference between a real problem and a temporary problem, you should not use FreeBSD-CURRENT. This branch sometimes evolves quite quickly and can be un-buildable for a number of days at a time. People that use FreeBSD-CURRENT are expected to be able to analyze any problems and only report them if they are deemed to be mistakes rather than glitches. Questions such as make world produces some error about groups on the -CURRENT mailing list may be treated with contempt. Every day, snapshot releases are made based on the current state of the -CURRENT and -STABLE branches. Distributions of the occasional snapshot are made available. The goals behind each snapshot release are: To test the latest version of the installation software. To give people who would like to run -CURRENT or -STABLE but who do not have the time or bandwidth to follow it on a day-to-day basis an easy way of bootstrapping it onto their systems. To preserve a fixed reference point for the code in question, just in case we break something really badly later. (Although CVS normally prevents anything horrible like this happening :) To ensure that all new features and fixes in need of testing have the greatest possible number of potential testers. No claims are made that any -CURRENT snapshot can be considered production quality for any purpose. If you want to run a stable and fully tested system, you will have to stick to full releases, or use the -STABLE snapshots. Snapshot releases are directly available from ftp://current.FreeBSD.org/pub/FreeBSD/ for 5-CURRENT and releng4.FreeBSD.org for 4-STABLE snapshots. 3-STABLE snapshots are not being produced at the time of this writing (May 2000). Snapshots are generated, on the average, daily for all actively developed branches. What is the FreeBSD-STABLE concept? Back when FreeBSD 2.0.5 was released, FreeBSD development branched in two. One branch was named -STABLE, one -CURRENT. FreeBSD-STABLE is intended for Internet Service Providers and other commercial enterprises for whom sudden shifts or experimental features are quite undesirable. It receives only well-tested bug fixes and other small incremental enhancements. FreeBSD-CURRENT, on the other hand, has been one unbroken line since 2.0 was released, leading towards 5.2-RELEASE (and beyond). At 5.2-RELEASE, the 5-STABLE branch is expected to be created, and &os.current; will become 6-CURRENT. If a little ASCII art would help, this is how it looks: 2.0 | | | [2.1-STABLE] *BRANCH* 2.0.5 -> 2.1 -> 2.1.5 -> 2.1.6 -> 2.1.7.1 [2.1-STABLE ends] | (Mar 1997) | | | [2.2-STABLE] *BRANCH* 2.2.1 -> 2.2.2-RELEASE -> 2.2.5 -> 2.2.6 -> 2.2.7 -> 2.2.8 [end] | (Mar 1997) (Oct 97) (Apr 98) (Jul 98) (Dec 98) | | 3.0-SNAPs (started Q1 1997) | | 3.0-RELEASE (Oct 1998) | | [3.0-STABLE] *BRANCH* 3.1-RELEASE (Feb 1999) -> 3.2 -> 3.3 -> 3.4 -> 3.5 -> 3.5.1 | (May 1999) (Sep 1999) (Dec 1999) (June 2000) (July 2000) | | [4.0-STABLE] *BRANCH* 4.0 (Mar 2000) -> 4.1 -> 4.1.1 -> 4.2 -> 4.3 -> 4.4 -> ... later 4.X releases ... | | (July 2000) (Sep 2000) (Nov 2000) 5.0-RELEASE (Jan 2003) | | 5.1-RELEASE (Jun 2003) | | \|/ + [5-CURRENT continues] The 2.2-STABLE branch was retired with the release of 2.2.8. The 3-STABLE branch has ended with the release of 3.5.1, the final 3.X release. The only changes made to either of these branches will be, for the most part, security-related bug fixes. 4-STABLE is the actively developed -STABLE branch. The latest release on the 4-STABLE branch is &rel2.current;-RELEASE, which was released in &rel2.current.date;. The 5-CURRENT branch is slowly progressing toward the creation of a 5-STABLE branch. See What is FreeBSD-CURRENT? for more information on this branch. When are FreeBSD releases made? The &a.re; releases a new version of FreeBSD about every four months, on average. Release dates are announced well in advance, so that the people working on the system know when their projects need to be finished and tested. A testing period precedes each release, in order to ensure that the addition of new features does not compromise the stability of the release. Many users regard this caution as one of the best things about FreeBSD, even though waiting for all the latest goodies to reach -STABLE can be a little frustrating. More information on the release engineering process (including a schedule of upcoming releases) can be found on the release engineering pages on the FreeBSD Web site. For people who need or want a little more excitement, binary snapshots are made daily as discussed above. Who is responsible for FreeBSD? The key decisions concerning the FreeBSD project, such as the overall direction of the project and who is allowed to add code to the source tree, are made by a core team of 9 people. There is a much larger team of more than 200 committers who are authorized to make changes directly to the FreeBSD source tree. However, most non-trivial changes are discussed in advance in the mailing lists, and there are no restrictions on who may take part in the discussion. Where can I get FreeBSD? Every significant release of FreeBSD is available via anonymous FTP from the FreeBSD FTP site: For the current 3.X-STABLE release, 3.5.1-RELEASE, see the 3.5.1-RELEASE directory. The latest 5.X release, &rel.current;-RELEASE can be found in the &rel.current;-RELEASE directory. The latest 4-STABLE release, &rel2.current;-RELEASE can be found in the &rel2.current;-RELEASE directory. 4.X snapshots are usually made daily. 5.0 Snapshot releases are made daily for the -CURRENT branch, these being of service purely to bleeding-edge testers and developers. Information about obtaining FreeBSD on CD, DVD, and other media can be found in the Handbook. How do I set up a FreeBSD mirror? Information on setting up a FreeBSD mirror can be found in the Mirroring FreeBSD article. How do I access the Problem Report database? The Problem Report database of all user change requests may be queried by using our web-based PR query interface. The &man.send-pr.1; command can be used to submit problem reports and change requests via electronic mail. The web-based problem report submission interface is currently disabled due to persistent abuse. Before submitting a problem report, please read Writing FreeBSD Problem Reports, an article on how to write good problem reports. How do I become a FreeBSD Web mirror? There are multiple ways to mirror the Web pages. You can retrieve the formatted files from a FreeBSD CVSup server using the application net/cvsup. The file /usr/share/examples/cvsup/www-supfile contains an example CVSup configuration file for web mirrors. You can download the web site source code from any FreeBSD FTP server using your favorite ftp mirror tool. Keep in mind that you have to build these sources before publishing them. Start mirroring at . What other sources of information are there? Please check the Documentation list on the main FreeBSD web site. Documentation and Support What good books are there about FreeBSD? The project produces a wide range of documentation, available online from this link: . The same documents are available as packages, that you can easily install on your FreeBSD system. More details on documentation packages can be found in the next paragraphs. In addition, the Bibliography at the end of this FAQ, and the one in the Handbook reference other recommended books. Is the documentation available in other formats, such as plain text (ASCII), or PostScript? Yes. The documentation is available in a number of different formats and compression schemes on the FreeBSD FTP site, in the /pub/FreeBSD/doc/ directory. The documentation is categorized in a number of different ways. These include: The document's name, such as faq, or handbook. The document's language and encoding. These are based on the locale names you will find under /usr/share/locale on your FreeBSD system. The current languages and encodings that we have for documentation are as follows: Name Meaning en_US.ISO8859-1 US English de_DE.ISO8859-1 German es_ES.ISO8859-1 Spanish fr_FR.ISO8859-1 French ja_JP.eucJP Japanese (EUC encoding) ru_RU.KOI8-R Russian (KOI8-R encoding) zh_TW.Big5 Chinese (Big5 encoding) Some documents may not be available in all languages. The document's format. We produce the documentation in a number of different output formats. Each format has its own advantages and disadvantages. Some formats are better suited for online reading, while others are meant to be aesthetically pleasing when printed on paper. Having the documentation available in any of these formats ensures that our readers will be able to read the parts they are interested in, either on their monitor, or on paper after printing the documents. The currently available formats are: Format Meaning html-split A collection of small, linked, HTML files. html One large HTML file containing the entire document pdb Palm Pilot database format, for use with the iSilo reader. pdf Adobe's Portable Document Format ps PostScript rtf Microsoft's Rich Text Format Page numbers are not automatically updated when loading this format into Word. Press CTRLA, CTRLEND, F9 after loading the document, to update the page numbers. txt Plain text The compression and packaging scheme. There are three of these currently in use. Where the format is html-split, the files are bundled up using &man.tar.1;. The resulting .tar file is then compressed using the compression schemes detailed in the next point. All the other formats generate one file, called book.format (i.e., book.pdb, book.html, and so on). These files are then compressed using three compression schemes. Scheme Description zip The Zip format. If you want to uncompress this on FreeBSD you will need to install the archivers/unzip port first. gz The GNU Zip format. Use &man.gunzip.1; to uncompress these files, which is part of FreeBSD. bz2 The BZip2 format. Less widespread than the others, but generally gives smaller files. Install the archivers/bzip2 port to uncompress these files. So the PostScript version of the Handbook, compressed using BZip2 will be stored in a file called book.ps.bz2 in the handbook/ directory. After choosing the format and compression mechanism that you want to download, you must then decide whether or not you want to download the document as a FreeBSD package. The advantage of downloading and installing the package is that the documentation can then be managed using the normal FreeBSD package management comments, such as &man.pkg.add.1; and &man.pkg.delete.1;. If you decide to download and install the package then you must know the filename to download. The documentation-as-packages files are stored in a directory called packages. Each package file looks like document-name.lang.encoding.format.tgz. For example, the FAQ, in English, formatted as PDF, is in the package called faq.en_US.ISO8859-1.pdf.tgz. Knowing this, you can use the following command to install the English PDF FAQ package. &prompt.root; pkg_add ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/packages/faq.en_US.ISO8859-1.pdf.tgz Having done that, you can use &man.pkg.info.1; to determine where the file has been installed. &prompt.root; pkg_info -f faq.en_US.ISO8859-1.pdf Information for faq.en_US.ISO8859-1.pdf: Packing list: Package name: faq.en_US.ISO8859-1.pdf CWD to /usr/share/doc/en_US.ISO8859-1/books/faq File: book.pdf CWD to . File: +COMMENT (ignored) File: +DESC (ignored) As you can see, book.pdf will have been installed into /usr/share/doc/en_US.ISO8859-1/books/faq. If you do not want to use the packages then you will have to download the compressed files yourself, uncompress them, and then copy the appropriate documents into place. For example, the split HTML version of the FAQ, compressed using &man.gzip.1;, can be found in the doc/en_US.ISO8859-1/books/faq/book.html-split.tar.gz file. To download and uncompress that file you would have to do this. &prompt.root; fetch ftp://ftp.FreeBSD.org/pub/FreeBSD/doc/en_US.ISO8859-1/books/faq/book.html-split.tar.gz &prompt.root; gzip -d book.html-split.tar.gz &prompt.root; tar xvf book.html-split.tar You will be left with a collection of .html files. The main one is called index.html, which will contain the table of contents, introductory material, and links to the other parts of the document. You can then copy or move these to their final location as necessary. Where do I find info on the FreeBSD mailing lists? You can find full information in the Handbook entry on mailing-lists. Where do I find the FreeBSD Y2K info? You can find full information in the FreeBSD Y2K page. What FreeBSD news groups are available? You can find full information in the Handbook entry on newsgroups. Are there FreeBSD IRC (Internet Relay Chat) channels? Yes, most major IRC networks host a FreeBSD chat channel: Channel #FreeBSD on EFNet is a FreeBSD forum, but do not go there for tech support or try to get folks there to help you avoid the pain of reading manual pages or doing your own research. It is a chat channel, first and foremost, and topics there are just as likely to involve sex, sports or nuclear weapons as they are FreeBSD. You Have Been Warned! Available at server irc.chat.org. Channel #FreeBSDhelp on EFNet is a channel dedicated to helping FreeBSD users. They are much more sympathetic to questions than #FreeBSD is. Channel #FreeBSD on DALNET is available at irc.dal.net in the US and irc.eu.dal.net in Europe. Channel #FreeBSD on UNDERNET is available at us.undernet.org in the US and eu.undernet.org in Europe. Since it is a help channel, be prepared to read the documents you are referred to. Channel #FreeBSD on HybNet. This channel is a help channel. A list of servers can be found on the HybNet web site. Each of these channels are distinct and are not connected to each other. Their chat styles also differ, so you may need to try each to find one suited to your chat style. As with all types of IRC traffic, if you are easily offended or cannot deal with lots of young people (and more than a few older ones) doing the verbal equivalent of jello wrestling, do not even bother with it. Where can I get commercial FreeBSD training and support? DaemonNews provides commercial training and support for FreeBSD. More information can be found at their BSD Mall site. FreeBSD Services Ltd provide commercial support for FreeBSD in the UK (as well as selling FreeBSD on DVD). See their web site for more information. The FreeBSD Mall provides commercial FreeBSD support. You can get more information at their web site. Any other organizations providing training and support should contact the project in order to be listed here. Nik Clayton
nik@FreeBSD.org
 Installation Which file do I download to get FreeBSD? Prior to release 3.1, you only needed one floppy image to install FreeBSD, namely floppies/boot.flp. However, since release 3.1 the Project has added out-of-the-box support for a wide variety of hardware, which takes up more space. For 3.X and later you need two floppy images: floppies/kernel.flp and floppies/mfsroot.flp. These images need to be copied onto floppies by tools like fdimage or &man.dd.1;. If you need to download the distributions yourself (for a DOS filesystem install, for instance), below are some recommendations for distributions to grab: bin/ manpages/ compat*/ doc/ src/ssys.* Full instructions on this procedure and a little bit more about installation issues in general can be found in the Handbook entry on installing FreeBSD. What do I do if the floppy images does not fit on a single floppy? A 3.5 inch (1.44MB) floppy can accommodate 1474560 bytes of data. The boot image is exactly 1474560 bytes in size. Common mistakes when preparing the boot floppy are: Not downloading the floppy image in binary mode when using FTP. Some FTP clients default their transfer mode to ascii and attempt to change any end-of-line characters received to match the conventions used by the client's system. This will almost invariably corrupt the boot image. Check the size of the downloaded boot image: if it is not exactly that on the server, then the download process is suspect. To workaround: type binary at the FTP command prompt after getting connected to the server and before starting the download of the image. Using the DOS copy command (or equivalent GUI tool) to transfer the boot image to floppy. Programs like copy will not work as the boot image has been created to be booted into directly. The image has the complete content of the floppy, track for track, and is not meant to be placed on the floppy as a regular file. You have to transfer it to the floppy raw, using the low-level tools (e.g. fdimage or rawrite) described in the installation guide to FreeBSD. Where are the instructions for installing FreeBSD? Installation instructions can be found in the Handbook entry on installing FreeBSD. What do I need in order to run FreeBSD? You will need a 386 or better PC, with 5 MB or more of RAM and at least 60 MB of hard disk space. It can run with a low end MDA graphics card but to run X11R6, a VGA or better video card is needed. See also . I have only 4 MB of RAM. Can I install FreeBSD? FreeBSD 2.1.7 was the last version of FreeBSD that could be installed on a 4MB system. FreeBSD 2.2 and later needs at least 5MB to install on a new system. All versions of FreeBSD will run in 4MB of RAM, they just cannot run the installation program in 4MB. You can add extra memory for the install process, if you like, and then after the system is up and running, go back to 4MB. Or you could swap your disk into a system which has >4MB, install onto the disk and then swap it back. After the installation, if you build a custom kernel, it will run in 4 MB. Someone has even successfully booted with 2 MB, although the system was almost unusable. How can I make my own custom install floppy? Currently there is no way to just make a custom install floppy. You have to cut a whole new release, which will include your install floppy. To make a custom release, follow the instructions in the Release Engineering article. Can I have more than one operating system on my PC? Have a look at the multi-OS page. Can Windows 95/98 co-exist with FreeBSD? Install Windows 95/98 first, after that FreeBSD. FreeBSD's boot manager will then manage to boot Win95/98 and FreeBSD. If you install Windows 95/98 second, it will boorishly overwrite your boot manager without even asking. If that happens, see the next section. Windows 95/98 killed my boot manager! How do I get it back? You can reinstall the boot manager FreeBSD comes with in one of three ways: Running DOS, go into the tools/ directory of your FreeBSD distribution and look for bootinst.exe. You run it like so: ...\TOOLS> bootinst.exe boot.bin and the boot manager will be reinstalled. Boot the FreeBSD boot floppy again and go to the Custom installation menu item. Choose Partition. Select the drive which used to contain your boot manager (likely the first one) and when you come to the partition editor for it, as the very first thing (e.g. do not make any changes) select (W)rite. This will ask for confirmation, say yes, and when you get the Boot Manager selection prompt, be sure to select Boot Manager. This will re-write the boot manager to disk. Now quit out of the installation menu and reboot off the hard disk as normal. Boot the FreeBSD boot floppy (or CDROM) and choose the Fixit menu item. Select either the Fixit floppy or CDROM #2 (the live filesystem option) as appropriate and enter the fixit shell. Then execute the following command: Fixit# fdisk -B -b /boot/boot0 bootdevice substituting bootdevice for your real boot device such as ad0 (first IDE disk), ad4 (first IDE disk on auxiliary controller), da0 (first SCSI disk), etc. My A, T, or X series IBM Thinkpad locks up when I first booted up my FreeBSD installation. How can I solve this? A bug in early revisions of IBM's BIOS on these machines mistakenly identifies the FreeBSD partition as a potential FAT suspend-to-disk partition. When the BIOS tries to parse the FreeBSD partition it hangs. According to IBMIn an e-mail from Keith Frechette kfrechet@us.ibm.com., the following model/BIOS release numbers incorporate the fix. Model BIOS revision T20 IYET49WW or later T21 KZET22WW or later A20p IVET62WW or later A20m IWET54WW or later A21p KYET27WW or later A21m KXET24WW or later A21e KUET30WW It has been reported that later IBM BIOS revisions may have reintroduced the bug. This message from Jacques Vidrine to the &a.mobile; describes a procedure which may work if your newer IBM laptop does not boot FreeBSD properly, and you can upgrade or downgrade the BIOS. If you have an earlier BIOS, and upgrading is not an option a workaround is to install FreeBSD, change the partition ID FreeBSD uses, and install new boot blocks that can handle the different partition ID. First, you will need to restore the machine to a state where it can get through its self-test screen. Doing this requires powering up the machine without letting it find a FreeBSD partition on its primary disk. One way is to remove the hard disk and temporarily move it to an older ThinkPad (such as a ThinkPad 600) or a desktop PC with an appropriate conversion cable. Once it is there, you can delete the FreeBSD partition and move the hard disk back. The ThinkPad should now be in a bootable state again. With the machine functional again, you can use the workaround procedure described here to get a working FreeBSD installation. Download boot1 and boot2 from . Put these files somewhere you will be able to retrieve them later. Install FreeBSD as normal on to the ThinkPad. Do not use Dangerously Dedicated mode. Do not reboot when the install has finished. Either switch to the Emergency Holographic Shell (ALT F4) or start a fixit shell. Use &man.fdisk.8; to change the FreeBSD partition ID from 165 to 166 (this is the type used by OpenBSD). Bring the boot1 and boot2 files to the local filesystem. Use &man.disklabel.8; to write boot1 and boot2 to your FreeBSD slice. &prompt.root; disklabel -B -b boot1 -s boot2 ad0sn n is the number of the slice where you installed FreeBSD. Reboot. At the boot prompt you will be given the option of booting OpenBSD. This will actually boot FreeBSD. Getting this to work in the case where you want to dual boot OpenBSD and FreeBSD on the same laptop is left as an exercise for the reader. Can I install on a disk with bad blocks? Prior to 3.0, FreeBSD included a utility known as bad144, which automatically remapped bad blocks. Because modern IDE drives perform this function themselves, bad144 has been removed from the FreeBSD source tree. If you wish to install FreeBSD 3.0 or later, we strongly suggest you purchase a newer disk drive. If you do not wish to do this, you must run FreeBSD 2.X. If you are seeing bad block errors with a modern IDE drive, chances are the drive is going to die very soon (the drive's internal remapping functions are no longer sufficient to fix the bad blocks, which means the disk is heavily corrupted); we suggest you buy a new hard drive. If you have a SCSI drive with bad blocks, see this answer. I have just upgraded from 3.X to 4.X, and my first boot failed with bad sector table not supported FreeBSD 3.X and earlier supported bad144, which automatically remapped bad blocks. FreeBSD 4.X and later do not support this, as modern IDE drives include this functionality. See this question for more information. To fix this after an upgrade, you need to physically place the drive in a working system and use &man.disklabel.8; as discussed in the following questions. How do I tell if a drive has bad144 information on it before I try to upgrade to FreeBSD 4.0 and it fails? Use &man.disklabel.8; for this. disklabel -r drive device will give you the contents of your disk label. Look for a flags field. If you see flags: badsect, this drive is using bad144. For example, the following drive has bad144 enabled.: &prompt.root; disklabel -r wd0 # /dev/rwd0c: type: ESDI disk: wd0s1 label: flags: badsect bytes/sector: 512 sectors/track: 63 How do I remove bad144 from my pre-4.X system so I can upgrade safely? Use disklabel -e -rwd0 to edit the disklabel in place. Just remove the word badsect from the flags field, save, and exit. The bad144 file will still take up some space on your drive, but the disk itself will be usable. We still recommend you purchase a new disk if you have a large number of bad blocks. Strange things happen when I boot the install floppy! What is happening? If you are seeing things like the machine grinding to a halt or spontaneously rebooting when you try to boot the install floppy, here are three questions to ask yourself:- Did you use a new, freshly-formatted, error-free floppy (preferably a brand-new one straight out of the box, as opposed to the magazine cover disk that has been lying under the bed for the last three years)? Did you download the floppy image in binary (or image) mode? (do not be embarrassed, even the best of us have accidentally downloaded a binary file in ASCII mode at least once!) If you are using Windows95 or Win98 did you run fdimage or rawrite in pure DOS mode? These operating systems can interfere with programs that write directly to hardware, which the disk creation program does; even running it inside a DOS shell in the GUI can cause this problem. There have also been reports of Netscape causing problems when downloading the boot floppy, so it is probably best to use a different FTP client if you can. I booted from my ATAPI CDROM, but the install program says no CDROM is found. Where did it go? The usual cause of this problem is a mis-configured CDROM drive. Many PCs now ship with the CDROM as the slave device on the secondary IDE controller, with no master device on that controller. This is illegal according to the ATAPI specification, but Windows plays fast and loose with the specification, and the BIOS ignores it when booting. This is why the BIOS was able to see the CDROM to boot from it, but why FreeBSD cannot see it to complete the install. Reconfigure your system so that the CDROM is either the master device on the IDE controller it is attached to, or make sure that it is the slave on an IDE controller that also has a master device. Can I install on my laptop over PLIP (Parallel Line IP)? Yes. Use a standard Laplink cable. If necessary, you can check out the PLIP section of the Handbook for details on parallel port networking. If you are running FreeBSD 3.X or earlier, also look at the Mobile Computing page. Which geometry should I use for a disk drive? By the geometry of a disk, we mean the number of cylinders, heads and sectors/track on a disk. We will refer to this as C/H/S for convenience. This is how the PC's BIOS works out which area on a disk to read/write from. This causes a lot of confusion among new system administrators. First of all, the physical geometry of a SCSI drive is totally irrelevant, as FreeBSD works in term of disk blocks. In fact, there is no such thing as the physical geometry, as the sector density varies across the disk. What manufacturers claim is the physical geometry is usually the geometry that they have determined wastes the least space. For IDE disks, FreeBSD does work in terms of C/H/S, but all modern drives internally convert this into block references. All that matters is the logical geometry. This is the answer that the BIOS gets when it asks the drive what is your geometry? It then uses this geometry to access the disk. As FreeBSD uses the BIOS when booting, it is very important to get this right. In particular, if you have more than one operating system on a disk, they must all agree on the geometry. Otherwise you will have serious problems booting! For SCSI disks, the geometry to use depends on whether extended translation support is turned on in your controller (this is often referred to as support for DOS disks >1GB or something similar). If it is turned off, then use N cylinders, 64 heads and 32 sectors/track, where N is the capacity of the disk in MB. For example, a 2GB disk should pretend to have 2048 cylinders, 64 heads and 32 sectors/track. If it is turned on (it is often supplied this way to get around certain limitations in MSDOS) and the disk capacity is more than 1GB, use M cylinders, 63 sectors per track (not 64), and 255 heads, where 'M' is the disk capacity in MB divided by 7.844238 (!). So our example 2GB drive would have 261 cylinders, 63 sectors per track and 255 heads. If you are not sure about this, or FreeBSD fails to detect the geometry correctly during installation, the simplest way around this is usually to create a small DOS partition on the disk. The BIOS should then detect the correct geometry, and you can always remove the DOS partition in the partition editor if you do not want to keep it. You might want to leave it around for programming network cards and the like, however. Alternatively, there is a freely available utility distributed with FreeBSD called pfdisk.exe. You can find it in the tools subdirectory on the FreeBSD CDROM or on the various FreeBSD FTP sites. This program can be used to work out what geometry the other operating systems on the disk are using. You can then enter this geometry in the partition editor. Are there any restrictions on how I divide the disk up? Yes. You must make sure that your root partition is below 1024 cylinders so the BIOS can boot the kernel from it. (Note that this is a limitation in the PC's BIOS, not FreeBSD). For a SCSI drive, this will normally imply that the root partition will be in the first 1024MB (or in the first 4096MB if extended translation is turned on - see previous question). For IDE, the corresponding figure is 504MB. Is FreeBSD compatible with any disk managers? FreeBSD recognizes the Ontrack Disk Manager and makes allowances for it. Other disk managers are not supported. If you just want to use the disk with FreeBSD you do not need a disk manager. Just configure the disk for as much space as the BIOS can deal with (usually 504 megabytes), and FreeBSD should figure out how much space you really have. If you are using an old disk with an MFM controller, you may need to explicitly tell FreeBSD how many cylinders to use. If you want to use the disk with FreeBSD and another operating system, you may be able to do without a disk manager: just make sure the FreeBSD boot partition and the slice for the other operating system are in the first 1024 cylinders. If you are reasonably careful, a 20 megabyte boot partition should be plenty. When I boot FreeBSD I get Missing Operating System. What is happening? This is classically a case of FreeBSD and DOS or some other OS conflicting over their ideas of disk geometry. You will have to reinstall FreeBSD, but obeying the instructions given above will almost always get you going. Why can I not get past the boot manager's F? prompt? This is another symptom of the problem described in the preceding question. Your BIOS geometry and FreeBSD geometry settings do not agree! If your controller or BIOS supports cylinder translation (often marked as >1GB drive support), try toggling its setting and reinstalling FreeBSD. Do I need to install the complete sources? In general, no. However, we would strongly recommend that you install, at a minimum, the base source kit, which includes several of the files mentioned here, and the sys (kernel) source kit, which includes sources for the kernel. There is nothing in the system which requires the presence of the sources to operate, however, except for the kernel-configuration program &man.config.8;. With the exception of the kernel sources, our build structure is set up so that you can read-only mount the sources from elsewhere via NFS and still be able to make new binaries (due to the kernel-source restriction, we recommend that you not mount this on /usr/src directly, but rather in some other location with appropriate symbolic links to duplicate the top-level structure of the source tree). Having the sources on-line and knowing how to build a system with them will make it much easier for you to upgrade to future releases of FreeBSD. To actually select a subset of the sources, use the Custom menu item when you are in the Distributions menu of the system installation tool. Do I need to build a kernel? Building a new kernel was originally pretty much a required step in a FreeBSD installation, but more recent releases have benefited from the introduction of a much friendlier kernel configuration tool. When at the FreeBSD boot prompt (boot:), use the flag and you will be dropped into a visual configuration screen which allows you to configure the kernel's settings for most common ISA cards. It is still recommended that you eventually build a new kernel containing just the drivers that you need, just to save a bit of RAM, but it is no longer a strict requirement for most systems. Should I use DES, Blowfish, or MD5 passwords and how do I specify which form my users receive? The default password format on FreeBSD is to use MD5-based passwords. These are believed to be more secure than the traditional Unix password format, which used a scheme based on the DES algorithm. DES passwords are still available if you need to share your password file with legacy operating systems which still use the less secure password format (they are available if you choose to install the crypto distribution in sysinstall, or by installing the crypto sources if building from source). Installing the crypto libraries will also allow you to use the Blowfish password format, which is more secure. Which password format to use for new passwords is controlled by the passwd_format login capability in /etc/login.conf, which takes values of des, blf (if these are available) or md5. See the &man.login.conf.5; manual page for more information about login capabilities. Why does the boot floppy start, but hang at the Probing Devices... screen? If you have a IDE Zip or Jaz drive installed, remove it and try again. The boot floppy can get confused by the drives. After the system is installed you can reconnect the drive. Hopefully this will be fixed in a later release. Why do I get a panic: can't mount root error when rebooting the system after installation? This error comes from confusion between the boot block's and the kernel's understanding of the disk devices. The error usually manifests on two-disk IDE systems, with the hard disks arranged as the master or single device on separate IDE controllers, with FreeBSD installed on the secondary IDE controller. The boot blocks think the system is installed on wd1 (the second BIOS disk) while the kernel assigns the first disk on the secondary controller device wd2. After the device probing, the kernel tries to mount what the boot blocks think is the boot disk, wd1, while it is really wd2, and fails. To fix the problem, do one of the following: For FreeBSD 3.3 and later, reboot the system and hit Enter at the Booting kernel in 10 seconds; hit [Enter] to interrupt prompt. This will drop you into the boot loader. Then type set root_disk_unit="disk_number" . disk_number will be 0 if FreeBSD is installed on the master drive on the first IDE controller, 1 if it is installed on the slave on the first IDE controller, 2 if it is installed on the master of the second IDE controller, and 3 if it is installed on the slave of the second IDE controller. Then type boot, and your system should boot correctly. To make this change permanent (ie so you do not have to do this every time you reboot or turn on your FreeBSD machine), put the line root_disk_unit="disk_number" in /boot/loader.conf.local . If using FreeBSD 3.2 or earlier, at the Boot: prompt, enter 1:wd(2,a)kernel and press Enter. If the system starts, then run the command echo "1:wd(2,a)kernel" > /boot.config to make it the default boot string. Move the FreeBSD disk onto the primary IDE controller, so the hard disks are consecutive. Rebuild your kernel, modify the wd configuration lines to read: controller wdc0 at isa? port "IO_WD1" bio irq 14 vector wdintr disk wd0 at wdc0 drive 0 # disk wd1 at wdc0 drive 1 # comment out this line controller wdc1 at isa? port "IO_WD2" bio irq 15 vector wdintr disk wd1 at wdc1 drive 0 # change from wd2 to wd1 disk wd2 at wdc1 drive 1 # change from wd3 to wd2 Install the new kernel. If you moved your disks and wish to restore the previous configuration, replace the disks in the desired configuration and reboot. Your system should boot successfully. What are the limits for memory? For memory, the limit is 4 gigabytes. If you plan to install this much memory into a machine, you need to be careful. You will probably want to use ECC memory and to reduce capacitive loading use 9 chip memory modules versus 18 chip memory modules. What are the limits for ffs filesystems? For ffs filesystems, the maximum theoretical limit is 8 terabytes (2G blocks), or 16TB for the default block size of 8K. In practice, there is a soft limit of 1 terabyte, but with modifications filesystems with 4 terabytes are possible (and exist). The maximum size of a single ffs file is approximately 1G blocks, or 4TB with a block size of 4K. Maximum file sizes fs block size 2.2.7-stable 3.0-current works should work 4K 4T-1 4T-1 4T-1 >4T 8K >32G 8T-1 >32G 32T-1 16K >128G 16T-1 >128G 32T-1 32K >512G 32T-1 >512G 64T-1 64K >2048G 64T-1 >2048G 128T-1
When the fs block size is 4K, triple indirect blocks work and everything should be limited by the maximum fs block number that can be represented using triple indirect blocks (approx. 1K^3 + 1K^2 + 1K), but everything is limited by a (wrong) limit of 1G-1 on fs block numbers. The limit on fs block numbers should be 2G-1. There are some bugs for fs block numbers near 2G-1, but such block numbers are unreachable when the fs block size is 4K. For block sizes of 8K and larger, everything should be limited by the 2G-1 limit on fs block numbers, but is actually limited by the 1G-1 limit on fs block numbers, except under -STABLE triple indirect blocks are unreachable, so the limit is the maximum fs block number that can be represented using double indirect blocks (approx. (blocksize/4)^2 + (blocksize/4)), and under -CURRENT exceeding this limit may cause problems. Using the correct limit of 2G-1 blocks does cause problems. Why do I get an error message, archsw.readin.failed after compiling and booting a new kernel? You can boot by specifying the kernel directly at the second stage, pressing any key when the | shows up before loader is started. More specifically, you have upgraded the source for your kernel, and installed a new kernel builtin from them without making world. This is not supported. Make world. How do I upgrade from 3.X -> 4.X? We strongly recommend that you use binary snapshots to do this. 4-STABLE snapshots are available at . Because of the many changes between 3.X and 4-STABLE, a direct upgrade from source will probably fail. A source upgrade can be done, but only in stages. First, upgrade to the latest 3-STABLE (RELENG_3). Then upgrade to 4.1.1-RELEASE (RELENG_4_1_1_RELEASE). Finally, upgrade to 4-STABLE (RELENG_4). If you wish to upgrade using source, please see the FreeBSD Handbook for more information. Upgrading via source is never recommended for new users, and upgrading from 3.X to 4.X is even less so; make sure you have read the instructions carefully before attempting to upgrade via source. What are these security profiles? A security profile is a set of configuration options that attempts to achieve the desired ratio of security to convenience by enabling and disabling certain programs and other settings. For full details, see the Security Profile section of the Handbook's post-install chapter. Hardware compatibility Does FreeBSD support architectures other than the x86? Yes. FreeBSD currently runs on Intel x86 and DEC (now Compaq) Alpha architectures. As of FreeBSD 5.0, the SPARC-64 architecture is also supported. Most recent additions to the list of upcoming platforms are IA-64, MIPS and PowerPC, join the &a.ia64;, the &a.ppc; or the &a.mips; respectively for more information about ongoing work on these platforms. For general discussion on new architectures, join the &a.platforms;. If your machine has a different architecture and you need something right now, we suggest you look at NetBSD or OpenBSD. I want to get a piece of hardware for my FreeBSD system. Which model/brand/type is best? This is discussed continually on the FreeBSD mailing lists. Since hardware changes so quickly, however, we expect this. We still strongly recommend that you read through the Hardware notes for &os; &rel.current; or &rel2.current; and search the mailing list archives before asking about the latest and greatest hardware. Chances are a discussion about the type of hardware you are looking for took place just last week. If you are looking for a laptop, check the FreeBSD-mobile mailing list archives. Otherwise, you probably want the archives for FreeBSD-questions, or possibly a specific mailing list for a particular hardware type. What kind of hard drives does FreeBSD support? FreeBSD supports EIDE and SCSI drives (with a compatible controller; see the next section), and all drives using the original Western Digital interface (MFM, RLL, ESDI, and of course IDE). A few ESDI controllers that use proprietary interfaces may not work: stick to WD1002/3/6/7 interfaces and clones. Which SCSI controllers are supported? See the complete list in the Hardware Notes for &os; &rel.current; or &rel2.current;. Which CDROM drives are supported by FreeBSD? Any SCSI drive connected to a supported controller is supported. The following proprietary CDROM interfaces are also supported: Mitsumi LU002 (8bit), LU005 (16bit) and FX001D (16bit 2x Speed). Sony CDU 31/33A Sound Blaster Non-SCSI CDROM Matsushita/Panasonic CDROM ATAPI compatible IDE CDROMs All non-SCSI cards are known to be extremely slow compared to SCSI drives, and some ATAPI CDROMs may not work. The official FreeBSD CDROM ISO, and CDROMs from Daemon News and FreeBSD Mall, support booting directly from the CD. Which CD-RW drives are supported by FreeBSD? FreeBSD supports any ATAPI-compatible IDE CD-R or CD-RW drive. For FreeBSD versions 4.0 and later, see the manual page for &man.burncd.8;. For earlier FreeBSD versions, see the examples in /usr/share/examples/atapi. FreeBSD also supports any SCSI CD-R or CD-RW drives. Install and use the cdrecord command from the ports or packages system, and make sure that you have the pass device compiled in your kernel. Does FreeBSD support ZIP drives? FreeBSD supports SCSI and ATAPI (IDE) ZIP drives out of the box, of course. SCSI ZIP drives can only be set to run at SCSI target IDs 5 or 6, but if your SCSI host adapter's BIOS supports it you can even boot from it. It is not clear which host adapters support booting from targets other than 0 or 1, so you will have to consult your adapter's documentation if you would like to use this feature. FreeBSD also supports Parallel Port Zip Drives. Check that your kernel contains the scbus0, da0, ppbus0, and vp0 drivers (the GENERIC kernel contains everything except vp0). With all these drivers present, the Parallel Port drive should be available as /dev/da0s4. Disks can be mounted using mount /dev/da0s4 /mnt OR (for dos disks) mount_msdos /dev/da0s4 /mnt as appropriate. Also check out the FAQ on removable drives later in this chapter, and the note on formattingin the Administration chapter. Does FreeBSD support JAZ, EZ and other removable drives? Apart from the IDE version of the EZ drive, these are all SCSI devices, so they should all look like SCSI disks to FreeBSD, and the IDE EZ should look like an IDE drive. I am not sure how well FreeBSD supports changing the media out while running. You will of course need to dismount the drive before swapping media, and make sure that any external units are powered on when you boot the system so FreeBSD can see them. See this note on formatting. Which multi-port serial cards are supported by FreeBSD? There is a list of these in the Miscellaneous devices section of the handbook. Some unnamed clone cards have also been known to work, especially those that claim to be AST compatible. Check the &man.sio.4; manual page to get more information on configuring such cards. Does FreeBSD support my USB keyboard? FreeBSD 4.X and later supports USB keyboards out-of-the-box. Preliminary USB device support appeared in FreeBSD 3.1, but might not always work as of version 3.2. If you want to experiment with the USB keyboard support in FreeBSD 3.X, follow the procedure described below. Use a version of FreeBSD 3.X later than 3.2. Add the following lines to your kernel configuration file, and rebuild the kernel. controller uhci0 controller ohci0 controller usb0 controller ukbd0 options KBD_INSTALL_CDEV Go to the /dev directory and create device nodes as follows: &prompt.root; cd /dev &prompt.root; ./MAKEDEV kbd0 kbd1 Edit /etc/rc.conf and add the following lines: usbd_enable="YES" usbd_flags="" If you want to use a USB keyboard in FreeBSD 4.X or later, you just need to enable USB support in /etc/rc.conf. Once you have USB keyboard support enabled on your system, the AT keyboard becomes /dev/kbd0 and the USB keyboard becomes /dev/kbd1, if both are connected to the system. If there is the USB keyboard only, it will be /dev/ukbd0. If you want to use the USB keyboard in the console, you have to explicitly tell the console driver to use the existing USB keyboard. This can be done by running the following command as a part of system initialization. &prompt.root; kbdcontrol -k /dev/kbd1 < /dev/ttyv0 > /dev/null Note that if the USB keyboard is the only keyboard, it is accessed as /dev/kbd0, thus, the command should look like: &prompt.root; kbdcontrol -k /dev/kbd0 < /dev/ttyv0 > /dev/null /etc/rc.i386 is a good place to add the above command. Once this is done, the USB keyboard should work in the X environment as well without any special settings. Hot-plugging and unplugging of the USB keyboard may not work quite right yet. We recommend connecting the keyboard before starting the system and leaving it connected until the system is shutdown to avoid troubles. See the &man.ukbd.4; manual page for more information. I have an unusual bus mouse. How do I set it up? FreeBSD supports the bus mouse and the InPort bus mouse from such manufactures as Microsoft, Logitech and ATI. The bus device driver is compiled in the GENERIC kernel by default in FreeBSD versions 2.X, but not included in version 3.0 or later. If you are building a custom kernel with the bus mouse driver, make sure to add the following line to the kernel config file In FreeBSD 3.0 or before, add: device mse0 at isa? port 0x23c tty irq5 vector mseintr In FreeBSD 3.X, the line should be: device mse0 at isa? port 0x23c tty irq5 And in FreeBSD 4.X and later, the line should read: device mse0 at isa? port 0x23c irq5 Bus mice usually comes with dedicated interface cards. These cards may allow you to set the port address and the IRQ number other than shown above. Refer to the manual of your mouse and the &man.mse.4; manual page for more information. How do I use my PS/2 (mouse port or keyboard) mouse? The PS/2 mouse is supported out-of-the-box in all recent versions of FreeBSD. The necessary device driver, psm, is included in the GENERIC kernel. If your custom kernel does not have this, add the appropriate following line to your kernel configuration file and compile a new kernel. In FreeBSD 3.0 or earlier, the line should be: device psm0 at isa? port "IO_KBD" conflicts tty irq 12 vector psmintr In FreeBSD 3.1 or later, the line should be: device psm0 at isa? tty irq 12 In FreeBSD 4.0 or later, the line should be: device psm0 at atkbdc? irq 12 Once the kernel detects psm0 correctly at boot time, make sure that an entry for psm0 exists in /dev. You can do this by typing: &prompt.root; cd /dev; sh MAKEDEV psm0 when logged in as root. You can omit this step if you are running FreeBSD 5.0-RELEASE or newer with &man.devfs.5; enabled, since the proper device nodes will be created automatically under /dev. Is it possible to use a mouse in any way outside the X Window system? If you are using the default console driver, &man.syscons.4;, you can use a mouse pointer in text consoles to cut & paste text. Run the mouse daemon, &man.moused.8;, and turn on the mouse pointer in the virtual console: &prompt.root; moused -p /dev/xxxx -t yyyy &prompt.root; vidcontrol -m on Where xxxx is the mouse device name and yyyy is a protocol type for the mouse. The mouse daemon can automatically determine the protocol type of most mice, except old serial mice. Specify the auto protocol to invoke automatic detection. If automatic detection does not work, see the &man.moused.8; manual page for a list of supported protocol types. If you have a PS/2 mouse, just add moused_enable="YES" to /etc/rc.conf to start the mouse daemon at boot-time. Additionally, if you would like to use the mouse daemon on all virtual terminals instead of just the console, add allscreens_flags="-m on" to /etc/rc.conf. When the mouse daemon is running, access to the mouse must be coordinated between the mouse daemon and other programs such as X Windows. Refer to the FAQ Why does my mouse not work with X? for more details on this issue. How do I cut and paste text with a mouse in the text console? Once you get the mouse daemon running (see the previous section), hold down the button 1 (left button) and move the mouse to select a region of text. Then, press the button 2 (middle button) to paste it at the text cursor. Pressing button 3 (right button) will extend the selected region of text. If your mouse does not have a middle button, you may wish to emulate one or remap buttons using mouse daemon options. See the &man.moused.8; manual page for details. Does FreeBSD support any USB mice? Preliminary USB device support was added to FreeBSD 3.1. It did not always work through early versions of 3.X. As of FreeBSD 4.0, USB devices should work out of the box. If you want to experiment with the USB mouse support under FreeBSD 3.X, follow the procedure described below. Use FreeBSD 3.2 or later. Add the following lines to your kernel configuration file, and rebuild the kernel. device uhci device ohci device usb device ums In versions of FreeBSD before 4.0, use this instead: controller uhci0 controller ohci0 controller usb0 device ums0 Go to the /dev directory and create a device node as follows: &prompt.root; cd /dev &prompt.root; ./MAKEDEV ums0 You can omit this step if you are running FreeBSD 5.0-RELEASE or newer with &man.devfs.5; enabled, since the proper device nodes will be created automatically under /dev. Edit /etc/rc.conf and add the following lines: moused_enable="YES" moused_type="auto" moused_port="/dev/ums0" moused_flags="" usbd_enable="YES" usbd_flags="" See the previous section for more detailed discussion on moused. In order to use the USB mouse in the X session, edit XF86Config. If you are using XFree86 3.3.2 or later, be sure to have the following lines in the Pointer section: Device "/dev/sysmouse" Protocol "Auto" If you are using earlier versions of XFree86, be sure to have the following lines in the Pointer section: Device "/dev/sysmouse" Protocol "SysMouse" Refer to another section on the mouse support in the X environment. Hot-plugging and unplugging of the USB mouse may not work quite right yet. It is a good idea connect the mouse before you start the system and leave it connected until the system is shutdown to avoid trouble. My mouse has a fancy wheel and buttons. Can I use them in FreeBSD? The answer is, unfortunately, It depends. These mice with additional features require specialized driver in most cases. Unless the mouse device driver or the user program has specific support for the mouse, it will act just like a standard two, or three button mouse. For the possible usage of wheels in the X Window environment, refer to that section. How do I use the mouse/trackball/touchpad on my laptop? Please refer to the answer to the previous question. Also check out the Mobile Computing page. What types of tape drives are supported? FreeBSD supports SCSI and QIC-36 (with a QIC-02 interface). This includes 8-mm (aka Exabyte) and DAT drives. Some of the early 8-mm drives are not quite compatible with SCSI-2, and may not work well with FreeBSD. Does FreeBSD support tape changers? FreeBSD supports SCSI changers using the &man.ch.4; device and the &man.chio.1; command. The details of how you actually control the changer can be found in the &man.chio.1; manual page. If you are not using AMANDA or some other product that already understands changers, remember that they only know how to move a tape from one point to another, so you need to keep track of which slot a tape is in, and which slot the tape currently in the drive needs to go back to. Which sound cards are supported by FreeBSD? FreeBSD supports the SoundBlaster, SoundBlaster Pro, SoundBlaster 16, Pro Audio Spectrum 16, AdLib and Gravis UltraSound sound cards. There is also limited support for MPU-401 and compatible MIDI cards. Cards conforming to the Microsoft Sound System specification are also supported through the pcm driver. This is only for sound! This driver does not support CDROMs, SCSI or joysticks on these cards, except for the SoundBlaster. The SoundBlaster SCSI interface and some non-SCSI CDROMs are supported, but you cannot boot off this device. Workarounds for no sound from es1370 with pcm driver? You can run the following command every time the machine booted up: &prompt.root; mixer pcm 100 vol 100 cd 100 Which network cards does FreeBSD support? See the Hardware Notes supplied with each release of FreeBSD for a more complete list. I do not have a math co-processor - is that bad? This will only affect 386/486SX/486SLC owners - other machines will have one built into the CPU. In general this will not cause any problems, but there are circumstances where you will take a hit, either in performance or accuracy of the math emulation code (see the section on FP emulation). In particular, drawing arcs in X will be VERY slow. It is highly recommended that you buy a math co-processor; it is well worth it. Some math co-processors are better than others. It pains us to say it, but nobody ever got fired for buying Intel. Unless you are sure it works with FreeBSD, beware of clones. What other devices does FreeBSD support? See the Handbook for the list of other devices supported. Does FreeBSD support power management on my laptop? FreeBSD supports APM on certain machines. Please look in the LINT kernel config file, searching for the APM keyword. Further information can be found in &man.apm.4;. Why does my Micron system hang at boot time? Certain Micron motherboards have a non-conforming PCI BIOS implementation that causes grief when FreeBSD boots because PCI devices do not get configured at their reported addresses. Disable the Plug and Play Operating System flag in the BIOS to work around this problem. More information can be found at http://cesdis.gsfc.nasa.gov/linux/drivers/vortex.html#micron Why is FreeBSD not finding my internal Plug & Play modem? You will need to add the modem's PnP ID to the PnP ID list in the serial driver. To enable Plug & Play support, compile a new kernel with controller pnp0 in the configuration file, then reboot the system. The kernel will print the PnP IDs of all the devices it finds. Copy the PnP ID from the modem to the table in /sys/i386/isa/sio.c, at about line 2777. Look for the string SUP1310 in the structure siopnp_ids[] to find the table. Build the kernel again, install, reboot, and your modem should be found. You may have to manually configure the PnP devices using the pnp command in the boot-time configuration with a command like pnp 1 0 enable os irq0 3 drq0 0 port0 0x2f8 to make the modem show. Does FreeBSD support software modems, such as Winmodems? FreeBSD supports many software modems via add-on software. The comms/ltmdm port adds support for modems based on the very popular Lucent LT chipset. The comms/mwavem port supports the modem in IBM Thinkpad 600 and 700 laptops. You cannot install FreeBSD via a software modem; this software must be installed after the OS is installed. How do I get the boot: prompt to show on the serial console? Build a kernel with options COMCONSOLE. Create /boot.config and place as the only text in the file. Unplug the keyboard from the system. See /usr/src/sys/i386/boot/biosboot/README.serial for information. Why does my 3Com PCI network card not work with my Micron computer? Certain Micron motherboards have a non-conforming PCI BIOS implementation that does not configure PCI devices at the addresses reported. This causes grief when FreeBSD boots. To work around this problem, disable the Plug and Play Operating System flag in the BIOS. More information on this problem is available at URL: Does FreeBSD support Symmetric Multiprocessing (SMP)? Yes. SMP is not enabled in the GENERIC kernel, so you must recompile your kernel to enable SMP. Take a look at /sys/i386/conf/LINT to learn what options to put in your kernel config file. The boot floppy hangs on a system with an ASUS K7V motherboard. How do I fix this? Go into the BIOS setup and disable the boot virus protection. Troubleshooting What do I do when I have bad blocks on my hard drive? With SCSI drives, the drive should be capable of re-mapping these automatically. However, many drives are shipped with this feature disabled, for some mysterious reason... To enable this, you will need to edit the first device page mode, which can be done on FreeBSD by giving the command (as root) &prompt.root; scsi -f /dev/rsd0c -m 1 -e -P 3 and changing the values of AWRE and ARRE from 0 to 1:- AWRE (Auto Write Reallocation Enbld): 1 ARRE (Auto Read Reallocation Enbld): 1 The following paragraphs were submitted by Ted Mittelstaedt tedm@toybox.placo.com: For IDE drives, any bad block is usually a sign of potential trouble. All modern IDE drives come with internal bad-block remapping turned on. All IDE hard drive manufacturers today offer extensive warranties and will replace drives with bad blocks on them. If you still want to attempt to rescue an IDE drive with bad blocks, you can attempt to download the IDE drive manufacturer's IDE diagnostic program, and run this against the drive. Sometimes these programs can be set to force the drive electronics to rescan the drive for bad blocks and lock them out. For ESDI, RLL and MFM drives, bad blocks are a normal part of the drive and are no sign of trouble, generally. With a PC, the disk drive controller card and BIOS handle the task of locking out bad sectors. This is fine for operating systems like DOS that use BIOS code to access the disk. However, FreeBSD's disk driver does not go through BIOS, therefore a mechanism, bad144, exists that replaces this functionality. bad144 only works with the wd driver (which means it is not supported in FreeBSD 4.0), it is NOT able to be used with SCSI. bad144 works by entering all bad sectors found into a special file. One caveat with bad144 - the bad block special file is placed on the last track of the disk. As this file may possibly contain a listing for a bad sector that would occur near the beginning of the disk, where the /kernel file might be located, it therefore must be accessible to the bootstrap program that uses BIOS calls to read the kernel file. This means that the disk with bad144 used on it must not exceed 1024 cylinders, 16 heads, and 63 sectors. This places an effective limit of 500MB on a disk that is mapped with bad144. To use bad144, simply set the Bad Block scanning to ON in the FreeBSD fdisk screen during the initial install. This works up through FreeBSD 2.2.7. The disk must have less than 1024 cylinders. It is generally recommended that the disk drive has been in operation for at least 4 hours prior to this to allow for thermal expansion and track wandering. If the disk has more than 1024 cylinders (such as a large ESDI drive) the ESDI controller uses a special translation mode to make it work under DOS. The wd driver understands about these translation modes, IF you enter the translated geometry with the set geometry command in fdisk. You must also NOT use the dangerously dedicated mode of creating the FreeBSD partition, as this ignores the geometry. Also, even though fdisk will use your overridden geometry, it still knows the true size of the disk, and will attempt to create a too large FreeBSD partition. If the disk geometry is changed to the translated geometry, the partition MUST be manually created with the number of blocks. A quick trick to use is to set up the large ESDI disk with the ESDI controller, boot it with a DOS disk and format it with a DOS partition. Then, boot the FreeBSD install and in the fdisk screen, read off and write down the blocksize and block numbers for the DOS partition. Then, reset the geometry to the same that DOS uses, delete the DOS partition, and create a cooperative FreeBSD partition using the blocksize you recorded earlier. Then, set the partition bootable and turn on bad block scanning. During the actual install, bad144 will run first, before any filesystems are created (you can view this with an AltF2). If it has any trouble creating the badsector file, you have set too large a disk geometry - reboot the system and start all over again (including repartitioning and reformatting with DOS). If remapping is enabled and you are seeing bad blocks, consider replacing the drive. The bad blocks will only get worse as time goes on. Why does FreeBSD not recognize my Bustek 742a EISA SCSI controller? This info is specific to the 742a but may also cover other Buslogic cards. (Bustek = Buslogic) There are 2 general versions of the 742a card. They are hardware revisions A-G, and revisions H - onwards. The revision letter is located after the Assembly number on the edge of the card. The 742a has 2 ROM chips on it, one is the BIOS chip and the other is the Firmware chip. FreeBSD does not care what version of BIOS chip you have but it does care about what version of firmware chip. Buslogic will send upgrade ROMs out if you call their tech support dept. The BIOS and Firmware chips are shipped as a matched pair. You must have the most current Firmware ROM in your adapter card for your hardware revision. The REV A-G cards can only accept BIOS/Firmware sets up to 2.41/2.21. The REV H- up cards can accept the most current BIOS/Firmware sets of 4.70/3.37. The difference between the firmware sets is that the 3.37 firmware supports round robin. The Buslogic cards also have a serial number on them. If you have an old hardware revision card you can call the Buslogic RMA department and give them the serial number and attempt to exchange the card for a newer hardware revision. If the card is young enough they will do so. FreeBSD 2.1 only supports Firmware revisions 2.21 onward. If you have a Firmware revision older than this your card will not be recognized as a Buslogic card. It may be recognized as an Adaptec 1540, however. The early Buslogic firmware contains an AHA1540 emulation mode. This is not a good thing for an EISA card, however. If you have an old hardware revision card and you obtain the 2.21 firmware for it, you will need to check the position of jumper W1 to B-C, the default is A-B. Why does FreeBSD not detect my HP Netserver's SCSI controller? This is basically a known problem. The EISA on-board SCSI controller in the HP Netserver machines occupies EISA slot number 11, so all the true EISA slots are in front of it. Alas, the address space for EISA slots >= 10 collides with the address space assigned to PCI, and FreeBSD's auto-configuration currently cannot handle this situation very well. So now, the best you can do is to pretend there is no address range clash :), by bumping the kernel option EISA_SLOTS to a value of 12. Configure and compile a kernel, as described in the Handbook entry on configuring the kernel. Of course, this does present you with a chicken-and-egg problem when installing on such a machine. In order to work around this problem, a special hack is available inside UserConfig. Do not use the visual interface, but the plain command-line interface there. Simply type eisa 12 quit at the prompt, and install your system as usual. While it is recommended you compile and install a custom kernel anyway. Hopefully, future versions will have a proper fix for this problem. You cannot use a dangerously dedicated disk with an HP Netserver. See this note for more info. I keep seeing messages like ed1: timeout. What do these messages mean? This is usually caused by an interrupt conflict (e.g., two boards using the same IRQ). FreeBSD prior to 2.0.5R used to be tolerant of this, and the network driver would still function in the presence of IRQ conflicts. However, with 2.0.5R and later, IRQ conflicts are no longer tolerated. Boot with the -c option and change the ed0/de0/... entry to match your board. If you are using the BNC connector on your network card, you may also see device timeouts because of bad termination. To check this, attach a terminator directly to the NIC (with no cable) and see if the error messages go away. Some NE2000 compatible cards will give this error if there is no link on the UTP port or if the cable is disconnected. Why did my 3COM 3C509 card stop working for no apparent reason? This card has a bad habit of losing its configuration information. Refresh your card's settings with the DOS utility 3c5x9.exe. My parallel printer is ridiculously slow. What can I do? If the only problem is that the printer is terribly slow, try changing your printer port mode as discussed in the Printer Setup section of the Handbook. Why do my programs occasionally die with Signal 11 errors? Signal 11 errors are caused when your process has attempted to access memory which the operating system has not granted it access to. If something like this is happening at seemingly random intervals then you need to start investigating things very carefully. These problems can usually be attributed to either: If the problem is occurring only in a specific application that you are developing yourself it is probably a bug in your code. If it is a problem with part of the base FreeBSD system, it may also be buggy code, but more often than not these problems are found and fixed long before us general FAQ readers get to use these bits of code (that is what -current is for). In particular, a dead giveaway that this is not a FreeBSD bug is if you see the problem when you are compiling a program, but the activity that the compiler is carrying out changes each time. For example, suppose you are running make buildworld, and the compile fails while trying to compile ls.c into ls.o. If you then run make buildworld again, and the compile fails in the same place then this is a broken build -- try updating your sources and try again. If the compile fails elsewhere then this is almost certainly hardware. What you should do: In the first case you can use a debugger e.g. gdb to find the point in the program which is attempting to access a bogus address and then fix it. In the second case you need to verify that it is not your hardware at fault. Common causes of this include: Your hard disks might be overheating: Check the fans in your case are still working, as your disk (and perhaps other hardware might be overheating). The processor running is overheating: This might be because the processor has been overclocked, or the fan on the processor might have died. In either case you need to ensure that you have hardware running at what it is specified to run at, at least while trying to solve this problem. i.e. Clock it back to the default settings. If you are overclocking then note that it is far cheaper to have a slow system than a fried system that needs replacing! Also the wider community is not often sympathetic to problems on overclocked systems, whether you believe it is safe or not. Dodgy memory: If you have multiple memory SIMMS/DIMMS installed then pull them all out and try running the machine with each SIMM or DIMM individually and narrow the problem down to either the problematic DIMM/SIMM or perhaps even a combination. Over-optimistic Motherboard settings: In your BIOS settings, and some motherboard jumpers you have options to set various timings, mostly the defaults will be sufficient, but sometimes, setting the wait states on RAM too low, or setting the RAM Speed: Turbo option, or similar in the BIOS will cause strange behavior. A possible idea is to set to BIOS defaults, but it might be worth noting down your settings first! Unclean or insufficient power to the motherboard. If you have any unused I/O boards, hard disks, or CDROMs in your system, try temporarily removing them or disconnecting the power cable from them, to see if your power supply can manage a smaller load. Or try another power supply, preferably one with a little more power (for instance, if your current power supply is rated at 250 Watts try one rated at 300 Watts). You should also read the SIG11 FAQ (listed below) which has excellent explanations of all these problems, albeit from a Linux viewpoint. It also discusses how memory testing software or hardware can still pass faulty memory. Finally, if none of this has helped it is possible that you have just found a bug in FreeBSD, and you should follow the instructions to send a problem report. There is an extensive FAQ on this at the SIG11 problem FAQ My system crashes with either Fatal trap 12: page fault in kernel mode, or panic:, and spits out a bunch of information. What should I do? The FreeBSD developers are very interested in these errors, but need some more information than just the error you see. Copy your full crash message. Then consult the FAQ section on kernel panics, build a debugging kernel, and get a backtrace. This might sound difficult, but you do not need any programming skills; you just have to follow the instructions. Why does the screen go black and lose sync when I boot? This is a known problem with the ATI Mach 64 video card. The problem is that this card uses address 2e8, and the fourth serial port does too. Due to a bug (feature?) in the &man.sio.4; driver it will touch this port even if you do not have the fourth serial port, and even if you disable sio3 (the fourth port) which normally uses this address. Until the bug has been fixed, you can use this workaround: Enter at the boot prompt. (This will put the kernel into configuration mode). Disable sio0, sio1, sio2 and sio3 (all of them). This way the sio driver does not get activated -> no problems. Type exit to continue booting. If you want to be able to use your serial ports, you will have to build a new kernel with the following modification: in /usr/src/sys/i386/isa/sio.c find the one occurrence of the string 0x2e8 and remove that string and the preceding comma (keep the trailing comma). Now follow the normal procedure of building a new kernel. Even after applying these workarounds, you may still find that the X Window System does not work properly. If this is the case, make sure that the XFree86 version you are using is at least XFree86 3.3.3 or higher. This version and upwards has built-in support for the Mach64 cards and even a dedicated X server for those cards. Why does FreeBSD only use 64 MB of RAM when my system has 128 MB of RAM installed? Due to the manner in which FreeBSD gets the memory size from the BIOS, it can only detect 16 bits worth of Kbytes in size (65535 Kbytes = 64MB) (or less... some BIOSes peg the memory size to 16M). If you have more than 64MB, FreeBSD will attempt to detect it; however, the attempt may fail. To work around this problem, you need to use the kernel option specified below. There is a way to get complete memory information from the BIOS, but we do not have room in the bootblocks to do it. Someday when lack of room in the bootblocks is fixed, we will use the extended BIOS functions to get the full memory information...but for now we are stuck with the kernel option. options "MAXMEM=n" Where n is your memory in Kilobytes. For a 128 MB machine, you would want to use 131072. Why does FreeBSD 2.0 panic with kmem_map too small!? The message may also be mb_map too small! The panic indicates that the system ran out of virtual memory for network buffers (specifically, mbuf clusters). You can increase the amount of VM available for mbuf clusters by adding: options "NMBCLUSTERS=n" to your kernel config file, where n is a number in the range 512-4096, depending on the number of concurrent TCP connections you need to support. I would recommend trying 2048 - this should get rid of the panic completely. You can monitor the number of mbuf clusters allocated/in use on the system with netstat -m (see &man.netstat.1;). The default value for NMBCLUSTERS is 512 + MAXUSERS * 16. Why do I get the error /kernel: proc: table is full? The FreeBSD kernel will only allow a certain number of processes to exist at one time. The number is based on the MAXUSERS option in the kernel configuration. MAXUSERS also affects various other in-kernel limits, such as network buffers (see this earlier question). If your machine is heavily loaded, you probably want to increase MAXUSERS. This will increase these other system limits in addition to the maximum number of processes. After FreeBSD 4.4, MAXUSERS became a tunable value that could be set with kern.maxusers in /boot/loader.conf. In earlier versions of FreeBSD, you need to adjust MAXUSERS in your kernel configuration. If your machine is lightly loaded, and you are simply running a very large number of processes, you can adjust this with the kern.maxproc sysctl. If these processes are being run by a single user, you will also need to adjust kern.maxprocperuid to be one less than your new kern.maxproc value. (It must be at least one less because one system program, &man.init.8;, must always be running.) To make a sysctl permanent across reboots, set this in /etc/sysctl.conf in recent versions of FreeBSD, or /etc/rc.local in older versions. Why do I get an error reading CMAP busy when rebooting with a new kernel? The logic that attempts to detect an out of date /var/db/kvm_*.db files sometimes fails and using a mismatched file can sometimes lead to panics. If this happens, reboot single-user and do: &prompt.root; rm /var/db/kvm_*.db What does the message ahc0: brkadrint, Illegal Host Access at seqaddr 0x0 mean? This is a conflict with an Ultrastor SCSI Host Adapter. During the boot process enter the kernel configuration menu and disable uha0, which is causing the problem. When I boot my system, I get the error ahc0: illegal cable configuration. My cabling is correct. What is going on? Your motherboard lacks the external logic to support automatic termination. Switch your SCSI BIOS to specify the correct termination for your configuration rather than automatic termination. The AIC7XXX driver cannot determine if the external logic for cable detection (and thus auto-termination) is available. The driver simply assumes that this support must exist if the configuration contained in the serial EEPROM is set to "automatic termination". Without the external cable detection logic the driver will often configure termination incorrectly, which can compromise the reliability of the SCSI bus. Why does Sendmail give me an error reading mail loops back to myself? This is answered in the sendmail FAQ as follows:- * I'm getting "Local configuration error" messages, such as: 553 relay.domain.net config error: mail loops back to myself 554 <user@domain.net>... Local configuration error How can I solve this problem? You have asked mail to the domain (e.g., domain.net) to be forwarded to a specific host (in this case, relay.domain.net) by using an MX record, but the relay machine does not recognize itself as domain.net. Add domain.net to /etc/mail/local-host-names (if you are using FEATURE(use_cw_file)) or add "Cw domain.net" to /etc/mail/sendmail.cf. The current version of the sendmail FAQ is no longer maintained with the sendmail release. It is however regularly posted to comp.mail.sendmail, comp.mail.misc, comp.mail.smail, comp.answers, and news.answers. You can also receive a copy via email by sending a message to mail-server@rtfm.mit.edu with the command send usenet/news.answers/mail/sendmail-faq as the body of the message. Why do full screen applications on remote machines misbehave? The remote machine may be setting your terminal type to something other than the cons25 terminal type required by the FreeBSD console. There are a number of possible work-arounds for this problem: After logging on to the remote machine, set your TERM shell variable to ansi or sco if the remote machine knows about these terminal types. Use a VT100 emulator like screen at the FreeBSD console. screen offers you the ability to run multiple concurrent sessions from one terminal, and is a neat program in its own right. Each screen window behaves like a VT100 terminal, so the TERM variable at the remote end should be set to vt100. Install the cons25 terminal database entry on the remote machine. The way to do this depends on the operating system on the remote machine. The system administration manuals for the remote system should be able to help you here. Fire up an X server at the FreeBSD end and login to the remote machine using an X based terminal emulator such as xterm or rxvt. The TERM variable at the remote host should be set to xterm or vt100. Why does my machine print calcru: negative time...? This can be caused by various hardware or software ailments relating to interrupts. It may be due to bugs but can also happen by nature of certain devices. Running TCP/IP over the parallel port using a large MTU is one good way to provoke this problem. Graphics accelerators can also get you here, in which case you should check the interrupt setting of the card first. A side effect of this problem are dying processes with the message SIGXCPU exceeded cpu time limit. For FreeBSD 3.0 and later from Nov 29, 1998 forward: If the problem cannot be fixed otherwise the solution is to set this sysctl variable: &prompt.root; sysctl -w kern.timecounter.method=1 The option of &man.sysctl.8; is deprecated and silently ignored in &os; 4.4-RELEASE and all newer versions. You can safely ommit it when setting options with sysctl as shown above. This means a performance impact, but considering the cause of this problem, you probably will not notice. If the problem persists, keep the sysctl set to one and set the NTIMECOUNTER option in your kernel to increasingly large values. If by the time you have reached NTIMECOUNTER=20 the problem is not solved, interrupts are too hosed on your machine for reliable time keeping. I see pcm0 not found or my sound card is found as pcm1 but I have device pcm0 in my kernel config file. What is going on? This occurs in FreeBSD 3.X with PCI sound cards. The pcm0 device is reserved exclusively for ISA-based cards so, if you have a PCI card, then you will see this error, and your card will appear as pcm1. You cannot remove the warning by simply changing the line in the kernel config file to device pcm1 as this will result in pcm1 being reserved for ISA cards and your PCI card being found as pcm2 (along with the warning pcm1 not found). If you have a PCI sound card you will also have to make the snd1 device rather than snd0: &prompt.root; cd /dev &prompt.root; ./MAKEDEV snd1 You can omit this step if you are running FreeBSD 5.0-RELEASE or newer with &man.devfs.5; enabled, since the proper device nodes will be created automatically under /dev. This situation does not arise in FreeBSD 4.X as a lot of work has been done to make it more PnP-centric and the pcm0 device is no longer reserved exclusively for ISA cards Why is my PnP card no longer found (or found as unknown) since upgrading to FreeBSD 4.X? FreeBSD 4.X is now much more PnP-centric and this has had the side effect of some PnP devices (e.g. sound cards and internal modems) not working even though they worked under FreeBSD 3.X. The reasons for this behavior are explained by the following e-mail, posted to the freebsd-questions mailing list by Peter Wemm, in answer to a question about an internal modem that was no longer found after an upgrade to FreeBSD 4.X (the comments in [] have been added to clarify the context. The contents of this quotation has been updated from its original text.
The PNP bios preconfigured it [the modem] and left it laying around in port space, so [in 3.X] the old-style ISA probes found it there. Under 4.0, the ISA code is much more PnP-centric. It was possible [in 3.X] for an ISA probe to find a stray device and then for the PNP device id to match and then fail due to resource conflicts. So, it disables the programmable cards first so this double probing cannot happen. It also means that it needs to know the PnP id's for supported PnP hardware. Making this more user tweakable is on the TODO list.
To get the device working again requires finding its PnP id and adding it to the list that the ISA probes use to identify PnP devices. This is obtained using &man.pnpinfo.8; to probe the device, for example this is the output from &man.pnpinfo.8; for an internal modem: &prompt.root; pnpinfo Checking for Plug-n-Play devices... Card assigned CSN #1 Vendor ID PMC2430 (0x3024a341), Serial Number 0xffffffff PnP Version 1.0, Vendor Version 0 Device Description: Pace 56 Voice Internal Plug & Play Modem Logical Device ID: PMC2430 0x3024a341 #0 Device supports I/O Range Check TAG Start DF I/O Range 0x3f8 .. 0x3f8, alignment 0x8, len 0x8 [16-bit addr] IRQ: 4 - only one type (true/edge) [more TAG lines elided] TAG End DF End Tag Successfully got 31 resources, 1 logical fdevs -- card select # 0x0001 CSN PMC2430 (0x3024a341), Serial Number 0xffffffff Logical device #0 IO: 0x03e8 0x03e8 0x03e8 0x03e8 0x03e8 0x03e8 0x03e8 0x03e8 IRQ 5 0 DMA 4 0 IO range check 0x00 activate 0x01 The information you require is in the Vendor ID line at the start of the output. The hexadecimal number in parentheses (0x3024a341 in this example) is the PnP id and the string immediately before this (PMC2430) is a unique ASCII id. Alternatively, if &man.pnpinfo.8; does not list the card in question, &man.pciconf.8; can be used instead. This is part of the output from pciconf -vl for an onboard sound chip: &prompt.root; pciconf -vl chip1@pci0:31:5: class=0x040100 card=0x00931028 chip=0x24158086 rev=0x02 hdr=0x00 vendor = 'Intel Corporation' device = '82801AA 8xx Chipset AC'97 Audio Controller' class = multimedia subclass = audio Here, you would use the chip value, 0x24158086. This information (Vendor ID or chip value) needs adding to the file /usr/src/sys/isa/sio.c. You should first make a backup of sio.c just in case things go wrong. You will also need it to make the patch to submit with your PR (you are going to submit a PR, are you not?) then edit sio.c and search for the line static struct isa_pnp_id sio_ids[] = { then scroll down to find the correct place to add the entry for your device. The entries look like this, and are sorted on the ASCII Vendor ID string which should be included in the comment to the right of the line of code along with all (if it will fit) or part of the Device Description from the output of &man.pnpinfo.8;: {0x0f804f3f, NULL}, /* OZO800f - Zoom 2812 (56k Modem) */ {0x39804f3f, NULL}, /* OZO8039 - Zoom 56k flex */ {0x3024a341, NULL}, /* PMC2430 - Pace 56 Voice Internal Modem */ {0x1000eb49, NULL}, /* ROK0010 - Rockwell ? */ {0x5002734a, NULL}, /* RSS0250 - 5614Jx3(G) Internal Modem */ Add the hexadecimal Vendor ID for your device in the correct place, save the file, rebuild your kernel, and reboot. Your device should now be found as an sio device as it was under FreeBSD 3.X Why do I get the error nlist failed when running, for example, top or systat? The problem is that the application you are trying to run is looking for a specific kernel symbol, but, for whatever reason, cannot find it; this error stems from one of two problems: Your kernel and userland are not synchronized (i.e., you built a new kernel but did not do an installworld, or vice versa), and thus the symbol table is different from what the user application thinks it is. If this is the case, simply complete the upgrade process (see /usr/src/UPDATING for the correct sequence). You are not using /boot/loader to load your kernel, but doing it directly from boot2 (see &man.boot.8;). While there is nothing wrong with bypassing /boot/loader, it generally does a better job of making the kernel symbols available to user applications. Why does it take so long to connect to my computer via ssh or telnet? The symptom: there is a long delay between the time the TCP connection is established and the time when the client software asks for a password (or, in &man.telnet.1;'s case, when a login prompt appears). The problem: more likely than not, the delay is caused by the server software trying to resolve the client's IP address into a hostname. Many servers, including the Telnet and SSH servers that come with FreeBSD, do this in order to, among other things, store the hostname in a log file for future reference by the administrator. The remedy: if the problem occurs whenever you connect from your computer (the client) to any server, the problem is with the client; likewise, if the problem only occurs when someone connects to your computer (the server) the problem is with the server. If the problem is with the client, the only remedy is to fix the DNS so the server can resolve it. If this is on a local network, consider it a server problem and keep reading; conversely, if this is on the global Internet, you will most likely need to contact your ISP and ask them to fix it for you. If the problem is with the server, and this is on a local network, you need to configure the server to be able to resolve address-to-hostname queries for your local address range. See the &man.hosts.5; and &man.named.8; manual pages for more information. If this is on the global Internet, the problem may be that your server's resolver is not functioning correctly. To check, try to look up another host--say, www.yahoo.com. If it does not work, that is your problem. What does stray IRQ mean? Stray IRQs are indications of hardware IRQ glitches, mostly from hardware that removes its interrupt request in the middle of the interrupt request acknowledge cycle. One has three options for dealing with this: Live with the warnings. All except the first 5 per irq are suppressed anyway. Break the warnings by changing 5 to 0 in isa_strayintr() so that all the warnings are suppressed. Break the warnings by installing parallel port hardware that uses irq 7 and the PPP driver for it (this happens on most systems), and install an ide drive or other hardware that uses irq 15 and a suitable driver for it. Why does file: table is full show up repeatedly in dmesg? This error message indicates you have exhausted the number of available file descriptors on your system. Please see the kern.maxfiles section of the Tuning Kernel Limits section of the Handbook for a discussion and solution. Why does the clock on my laptop keep incorrect time? Your laptop has two or more clocks, and FreeBSD has chosen to use the wrong one. Run &man.dmesg.8;, and check for lines that contain Timecounter. The last line printed is the one that FreeBSD chose, and will almost certainly be TSC. &prompt.root; dmesg | grep Timecounter Timecounter "i8254" frequency 1193182 Hz Timecounter "TSC" frequency 595573479 Hz You can confirm this by checking the kern.timecounter.hardware &man.sysctl.3;. &prompt.root; sysctl kern.timecounter.hardware kern.timecounter.hardware: TSC The BIOS may modify the TSC clock—perhaps to change the speed of the processor when running from batteries, or going into a power saving mode, but FreeBSD is unaware of these adjustments, and appears to gain or lose time. In this example, the i8254 clock is also available, and can be selected by writing its name to the kern.timecounter.hardware &man.sysctl.3;. &prompt.root; sysctl -w kern.timecounter.hardware=i8254 kern.timecounter.hardware: TSC -> i8254 Your laptop should now start keeping more accurate time. To have this change automatically run at boot time, add the following line to /etc/sysctl.conf. kern.timecounter.hardware=i8254 Why did my laptop fail to correctly probe PC cards? This problem is common on laptops that boot more than one operating system. Some non-BSD operating systems leave PC card hardware in an inconsistent state. pccardd will detect the card as "(null)""(null)" instead of its actual model. You must remove all power from the PC card slot to fully reset the hardware. Completely power off the laptop. (Don't suspend it, don't let it go into standby; the power needs to be completely off.) Wait a few moments, and reboot. Your PC card should work now. Some laptop hardware lies when it claims to be off. If the above does not work shut down, remove the battery, wait a moment, replace the battery, and reboot. Why does FreeBSD's boot loader display Read error and stop after the BIOS screen? FreeBSD's boot loader is incorrectly recognizing the hard drive's geometry. This must be manually set within fdisk when creating or modifying FreeBSD's slice. The correct drive geometry values can be found within the machine's BIOS. Look for the number of cylinders, heads and sectors for the particular drive. Within &man.sysinstall.8;'s fdisk, hit G to set the drive geometry. A dialog will pop up requesting the number of cylinders, heads and sectors. Type the numbers found from the BIOS separates by forward slashes. 5000 cylinders, 250 sectors and 60 sectors would be entered as 5000/250/60 Press enter to set the values, and hit W to write the new partition table to the drive. Another operating system destroyed my Boot Manager. How do I get it back? Enter &man.sysinstall.8; and choose Configure, then Fdisk. Select the disk the Boot Manager resided on with the space key. Press W to write changes to the drive. A prompt will appear asking which boot loader to install. Select this, and it will be restored. What does the error swap_pager: indefinite wait buffer: mean? This means that a process is trying to page memory to disk, and the page attempt has hung trying to access the disk for more than 20 seconds. It might be caused by bad blocks on the disk drive, disk wiring, cables, or any other disk I/O-related hardware. If the drive itself is actually bad, you will also see disk errors in /var/log/messages and in the output of dmesg. Otherwise, check your cables and connections. What are UDMA ICRC errors, and how do I fix them? The &man.ata.4; driver reports UDMA ICRC errors when a DMA transfer to or from a drive is corrupted. The driver will retry the operation a few times. Should the retries fail, it will switch from DMA to the slower PIO mode of communication with the device. The problem can be caused by many factors, although perhaps the most common cause is faulty or incorrect cabling. Check that the ATA cables are undamaged and rated for the Ultra DMA mode in use. If you're using removable drive trays, they must also be compatible. Be sure that all connections are making good contact. Problems have also been noticed when an old drive is installed on the same ATA channel as an Ultra DMA 66 (or faster) drive. Lastly, these errors can indicate that the drive is failing. Most drive vendors provide testing software for their drives, so test your drive, and, if necessary, back up your data and replace it. The &man.atacontrol.8; utility can be used to show and select the DMA or PIO modes used for each ATA device. In particular, atacontrol mode channel will show the modes in use on a particular ATA channel, where the primary channel is numbered 0, and so on. Commercial Applications This section is still very sparse, though we are hoping, of course, that companies will add to it! :) The FreeBSD group has no financial interest in any of the companies listed here but simply lists them as a public service (and feels that commercial interest in FreeBSD can have very positive effects on FreeBSD's long-term viability). We encourage commercial software vendors to send their entries here for inclusion. See the Vendors page for a longer list. Where can I get an Office Suite for FreeBSD? The FreeBSD Mall offers a FreeBSD native version of VistaSource ApplixWare 5. ApplixWare is a rich full-featured, commercial Office Suite for FreeBSD containing a word processor, spreadsheet, presentation program, vector drawing package, and other applications. ApplixWare is offered as part of the FreeBSD Mall's BSD Desktop Edition. The Linux version of StarOffice works flawlessly on FreeBSD. The easiest way to install the Linux version of StarOffice is through the FreeBSD Ports collection. Future versions of the open-source OpenOffice suite should work as well. Where can I get Motif for FreeBSD? The Open Group has released the source code to Motif 2.1.30. You can install the open-motif package, or compile it from ports. Refer to the ports section of the Handbook for more information on how to do this. The Open Motif distribution only allows redistribution if it is running on an open source operating system. In addition, there are commercial distributions of the Motif software available. These, however, are not for free, but their license allows them to be used in closed-source software. Contact Apps2go for the least expensive ELF Motif 2.1.20 distribution for FreeBSD (either i386 or Alpha). There are two distributions, the development edition and the runtime edition (for much less). These distributions includes: OSF/Motif manager, xmbind, panner, wsm. Development kit with uil, mrm, xm, xmcxx, include and Imake files. Static and dynamic ELF libraries (for use with FreeBSD 3.0 and above). Demonstration applets. Be sure to specify that you want the FreeBSD version of Motif when ordering (do not forget to mention the architecture you want too)! Versions for NetBSD and OpenBSD are also sold by Apps2go. This is currently a FTP only download. More info Apps2go WWW page or sales@apps2go.com or support@apps2go.com or phone (817) 431 8775 or +1 817 431-8775 Contact Metro Link for an either ELF or a.out Motif 2.1 distribution for FreeBSD. This distribution includes: OSF/Motif manager, xmbind, panner, wsm. Development kit with uil, mrm, xm, xmcxx, include and Imake files. Static and dynamic libraries (specify ELF for use with FreeBSD 3.0 and later; or a.out for use with FreeBSD 2.2.8 and earlier). Demonstration applets. Preformatted manual pages. Be sure to specify that you want the FreeBSD version of Motif when ordering! Versions for Linux are also sold by Metro Link. This is available on either a CDROM or for FTP download. Contact Xi Graphics for an a.out Motif 2.0 distribution for FreeBSD. This distribution includes: OSF/Motif manager, xmbind, panner, wsm. Development kit with uil, mrm, xm, xmcxx, include and Imake files. Static and dynamic libraries (for use with FreeBSD 2.2.8 and earlier). Demonstration applets. Preformatted manual pages. Be sure to specify that you want the FreeBSD version of Motif when ordering! Versions for BSDI and Linux are also sold by Xi Graphics. This is currently a 4 diskette set... in the future this will change to a unified CD distribution like their CDE. Where can I get CDE for FreeBSD? Xi Graphics used to sell CDE for FreeBSD, but no longer do. KDE is an open source X11 desktop which is similar to CDE in many respects. You might also like the look and feel of xfce. KDE and xfce are both in the ports system. Are there any commercial high-performance X servers? Yes, Xi Graphics and Metro Link sell Accelerated-X product for FreeBSD and other Intel based systems. The Metro Link offering is a high performance X Server that offers easy configuration using the FreeBSD Package suite of tools, support for multiple concurrent video boards and is distributed in binary form only, in a convenient FTP download. Not to mention the Metro Link offering is available at the very reasonable price of $39. Metro Link also sells both ELF and a.out Motif for FreeBSD (see above). More info Metro Link WWW page or sales@metrolink.com or tech@metrolink.com or phone (954) 938-0283 or +1 954 938-0283 The Xi Graphics offering is a high performance X Server that offers easy configuration, support for multiple concurrent video boards and is distributed in binary form only, in a unified diskette distribution for FreeBSD and Linux. Xi Graphics also offers a high performance X Server tailored for laptop support. There is a free compatibility demo of version 5.0 available. Xi Graphics also sells Motif and CDE for FreeBSD (see above). More info Xi Graphics WWW page or sales@xig.com or support@xig.com or phone (800) 946 7433 or +1 303 298-7478. Are there any Database systems for FreeBSD? Yes! See the Commercial Vendors section of FreeBSD's Web site. Also see the Databases section of the Ports collection. Can I run Oracle on FreeBSD? Yes. The following pages tell you exactly how to setup Linux-Oracle on FreeBSD: http://www.scc.nl/~marcel/howto-oracle.html http://www.lf.net/lf/pi/oracle/install-linux-oracle-on-freebsd User Applications So, where are all the user applications? Please take a look at the ports page for info on software packages ported to FreeBSD. The list currently tops &os.numports; and is growing daily, so come back to check often or subscribe to the freebsd-announce mailing list for periodic updates on new entries. Most ports should work on the 4.X and 5.X branches. Each time a FreeBSD release is made, a snapshot of the ports tree at the time of release in also included in the ports/ directory. We also support the concept of a package, essentially no more than a gzipped binary distribution with a little extra intelligence embedded in it for doing whatever custom installation work is required. A package can be installed and uninstalled again easily without having to know the gory details of which files it includes. Use the package installation menu in /stand/sysinstall (under the post-configuration menu item) or invoke the &man.pkg.add.1; command on the specific package files you are interested in installing. Package files can usually be identified by their .tgz suffix and CDROM distribution people will have a packages/All directory on their CD which contains such files. They can also be downloaded over the net for various versions of FreeBSD at the following locations: for 4.X-RELEASE/4-STABLE ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-4-stable/ for 5.X-CURRENT ftp://ftp.FreeBSD.org/pub/FreeBSD/ports/i386/packages-5-current or your nearest local mirror site. Note that all ports may not be available as packages since new ones are constantly being added. It is always a good idea to check back periodically to see which packages are available at the ftp.FreeBSD.org master site. Why does ghostscript give lots of errors with my 386/486SX? You do not have a math co-processor, right? You will need to add the alternative math emulator to your kernel; you do this by adding the following to your kernel config file and it will be compiled in. options GPL_MATH_EMULATE You will need to remove the MATH_EMULATE option when you do this. How do I configure INN (Internet News) for my machine? After installing the news/inn package or port, an excellent place to start is Dave Barr's INN Page where you will find the INN FAQ. What version of Microsoft FrontPage should I get? Use the Port, Luke! A pre-patched version of Apache, apache13-fp, is available in the ports tree. Does FreeBSD support Java? Yes. Please see http://www.FreeBSD.org/java/. Why can I not build this port on my 3.X-STABLE machine? If you are running a FreeBSD version that lags significantly behind -CURRENT or -STABLE, you may need a ports upgrade kit from http://www.FreeBSD.org/ports/. If you are up to date, then someone might have committed a change to the port which works for -CURRENT but which broke the port for -STABLE. Please submit a bug report on this with the &man.send-pr.1; command, since the ports collection is supposed to work for both the -CURRENT and -STABLE branches. Where do I find ld.so? a.out applications like Netscape Navigator require a.out libraries. A version of FreeBSD built with ELF libraries does not install them by default. You will get complaints about not having /usr/libexec/ld.so if this is the case on your system. These libraries are available as an add-on in the compat22 distribution. Use &man.sysinstall.8; to install them. You can also install them from the FreeBSD source code: &prompt.root; cd /usr/src/lib/compat/compat22 &prompt.root; make install clean If you want to install the latest compat22 libraries whenever you run make world, edit /etc/make.conf to include COMPAT22=YES. Old compatibility libraries change rarely, if ever, so this is not generally needed. Also see the ERRATAs for 3.1-RELEASE and 3.2-RELEASE. I updated the sources, now how do I update my installed ports? FreeBSD does not include a port upgrading tool, but it does have some tools to make the upgrade process somewhat easier. You can also install additional tools to simplify port handling. The &man.pkg.version.1; command can generate a script that will update installed ports to the latest version in the ports tree. &prompt.root; pkg_version -c > /tmp/myscript The output script must be edited by hand before you use it. Recent versions of &man.pkg.version.1; force this by inserting an &man.exit.1; at the beginning of the script. You should save the output of the script, as it will note packages that depend on the one that has been updated. These may or may not need to be updated as well. The usual case where they need to be updated is that a shared library has changed version numbers, so the ports that used that library need to be rebuilt to use the new version. Beginning with FreeBSD 5.0 (and higher revisions), &man.pkg.version.1; no longer supports the option. If you have the disk space, you can use the portupgrade tool to automate all of this. portupgrade includes various tools to simplify package handling. It is available under sysutils/portupgrade. Since it is written in Ruby, portupgrade is an unlikely candidate for integration with the main FreeBSD tree. That should not stop anyone from using it, however. If your system is up full time, the &man.periodic.8; system can be used to generate a weekly list of ports that might need updating by setting weekly_status_pkg_enable="YES" in /etc/periodic.conf. Why is /bin/sh so minimal? Why does FreeBSD not use bash or another shell? Because POSIX says that there shall be such a shell. The more complicated answer: many people need to write shell scripts which will be portable across many systems. That is why POSIX specifies the shell and utility commands in great detail. Most scripts are written in Bourne shell, and because several important programming interfaces (&man.make.1;, &man.system.3;, &man.popen.3;, and analogues in higher-level scripting languages like Perl and Tcl) are specified to use the Bourne shell to interpret commands. Because the Bourne shell is so often and widely used, it is important for it to be quick to start, be deterministic in its behavior, and have a small memory footprint. The existing implementation is our best effort at meeting as many of these requirements simultaneously as we can. In order to keep /bin/sh small, we have not provided many of the convenience features that other shells have. That is why the Ports Collection includes more featureful shells like bash, scsh, tcsh, and zsh. (You can compare for yourself the memory utilization of all these shells by looking at the VSZ and RSS columns in a ps -u listing.) Why do Netscape and Opera take so long to start? The usual answer is that DNS on your system is misconfigured. Both Netscape and Opera perform DNS checks when starting up. The browser will not appear on your desktop until the program either gets a response or determines that the system has no network connection. I updated parts of the Ports Collection using CVSup, and now many ports fail to build with mysterious error messages! What happened? Is the Ports Collection broken in some major way? If you only update parts of the Ports Collection, using one of its CVSup subcollections and not the ports-all CVSup collection, you should always update the ports-base subcollection too! The reasons are described in the Handbook. How do I create audio CDs from my MIDI files? To create audio CDs from MIDI files, first install audio/timidity++ from ports then install manually the GUS patches set by Eric A. Welsh, available at . After timidity++ has been installed properly, midi files may be converted to wav's with the following command line: &prompt.user; timidity -Ow -s 44100 -o /tmp/juke/01.wav 01.mid The wav files can then be converted to other formats or burned onto audio CDs, as described in the FreeBSD Handbook. Kernel Configuration I would like to customize my kernel. Is it difficult? Not at all! Check out the kernel config section of the Handbook. We recommend that you make a dated snapshot of your new /kernel called /kernel.YYMMDD after you get it working properly. Also back up your new /modules directory to /modules.YYMMDD. That way, if you make a mistake the next time you play with your configuration you can boot the backup kernel instead of having to fall back to kernel.GENERIC. This is particularly important if you are now booting from a controller that GENERIC does not support. My kernel compiles fail because _hw_float is missing. How do I solve this problem? Let me guess. You removed npx0 (see &man.npx.4;) from your kernel configuration file because you do not have a math co-processor, right? Wrong! :-) The npx0 is MANDATORY. Even if you do not have a mathematic co-processor, you must include the npx0 device. Why is my kernel so big (over 10MB)? Chances are, you compiled your kernel in debug mode. Kernels built in debug mode contain many symbols that are used for debugging, thus greatly increasing the size of the kernel. Note that if you running a FreeBSD 3.0 or later system, there will be little or no performance decrease from running a debug kernel, and it is useful to keep one around in case of a system panic. However, if you are running low on disk space, or you simply do not want to run a debug kernel, make sure that both of the following are true: You do not have a line in your kernel configuration file that reads: makeoptions DEBUG=-g You are not running &man.config.8; with the option. Both of the above situations will cause your kernel to be built in debug mode. As long as you make sure you follow the steps above, you can build your kernel normally, and you should notice a fairly large size decrease; most kernels tend to be around 1.5MB to 2MB. Why do I get interrupt conflicts with multi-port serial code? When I compile a kernel with multi-port serial code, it tells me that only the first port is probed and the rest skipped due to interrupt conflicts. How do I fix this? The problem here is that FreeBSD has code built-in to keep the kernel from getting trashed due to hardware or software conflicts. The way to fix this is to leave out the IRQ settings on all but one port. Here is an example: # # Multiport high-speed serial line - 16550 UARTS # device sio2 at isa? port 0x2a0 tty irq 5 flags 0x501 vector siointr device sio3 at isa? port 0x2a8 tty flags 0x501 vector siointr device sio4 at isa? port 0x2b0 tty flags 0x501 vector siointr device sio5 at isa? port 0x2b8 tty flags 0x501 vector siointr Why does every kernel I try to build fail to compile, even GENERIC? There are a number of possible causes for this problem. They are, in no particular order: You are not using the new make buildkernel and make installkernel targets, and your source tree is different from the one used to build the currently running system (e.g., you are compiling 4.3-RELEASE on a 4.0-RELEASE system). If you are attempting an upgrade, please read the /usr/src/UPDATING file, paying particular attention to the COMMON ITEMS section at the end. You are using the new make buildkernel and make installkernel targets, but you failed to assert the completion of the make buildworld target. The make buildkernel target relies on files generated by the make buildworld target to complete its job correctly. Even if you are trying to build FreeBSD-STABLE, it is possible that you fetched the source tree at a time when it was either being modified, or broken for other reasons; only releases are absolutely guaranteed to be buildable, although FreeBSD-STABLE builds fine the majority of the time. If you have not already done so, try re-fetching the source tree and see if the problem goes away. Try using a different server in case the one you are using is having problems. How can I verify which scheduler is in use on a running system? Just type: &prompt.root; sysctl kern.quantum If you see unknown oid 'kern.quantum' it means that the current scheduler is SCHED_ULE, however, if you see kern.quantum: 100000 then the original scheduler SCHED_4BSD is the current selection. What is 'kern.quantum'? kern.quantum is the maximum number of ticks a process can run without being preempted. It is specific to the 4BSD scheduler, so you can use its presence or absence to determine which scheduler is in use. Disks, Filesystems, and Boot Loaders How can I add my new hard disk to my FreeBSD system? See the Disk Formatting Tutorial at www.FreeBSD.org. How do I move my system over to my huge new disk? The best way is to reinstall the OS on the new disk, then move the user data over. This is highly recommended if you have been tracking -STABLE for more than one release, or have updated a release instead of installing a new one. You can install booteasy on both disks with &man.boot0cfg.8;, and dual boot them until you are happy with the new configuration. Skip the next paragraph to find out how to move the data after doing this. Should you decide not to do a fresh install, you need to partition and label the new disk with either /stand/sysinstall, or &man.fdisk.8; and &man.disklabel.8;. You should also install booteasy on both disks with &man.boot0cfg.8;, so that you can dual boot to the old or new system after the copying is done. See the formatting-media article for details on this process. Now you have the new disk set up, and are ready to move the data. Unfortunately, you cannot just blindly copy the data. Things like device files (in /dev), flags, and links tend to screw that up. You need to use tools that understand these things, which means &man.dump.8;. Although it is suggested that you move the data in single user mode, it is not required. You should never use anything but &man.dump.8; and &man.restore.8; to move the root filesystem. The &man.tar.1; command may work - then again, it may not. You should also use &man.dump.8; and &man.restore.8; if you are moving a single partition to another empty partition. The sequence of steps to use dump to move a partitions data to a new partition is: newfs the new partition. mount it on a temporary mount point. cd to that directory. dump the old partition, piping output to the new one. For example, if you are going to move root to /dev/ad1s1a, with /mnt as the temporary mount point, it is: &prompt.root; newfs /dev/ad1s1a &prompt.root; mount /dev/ad1s1a /mnt &prompt.root; cd /mnt &prompt.root; dump 0af - / | restore xf - Rearranging your partitions with dump takes a bit more work. To merge a partition like /var into its parent, create the new partition large enough for both, move the parent partition as described above, then move the child partition into the empty directory that the first move created: &prompt.root; newfs /dev/ad1s1a &prompt.root; mount /dev/ad1s1a /mnt &prompt.root; cd /mnt &prompt.root; dump 0af - / | restore xf - &prompt.root; cd var &prompt.root; dump 0af - /var | restore xf - To split a directory from its parent, say putting /var on its own partition when it was not before, create both partitions, then mount the child partition on the appropriate directory in the temporary mount point, then move the old single partition: &prompt.root; newfs /dev/ad1s1a &prompt.root; newfs /dev/ad1s1d &prompt.root; mount /dev/ad1s1a /mnt &prompt.root; mkdir /mnt/var &prompt.root; mount /dev/ad1s1d /mnt/var &prompt.root; cd /mnt &prompt.root; dump 0af - / | restore xf - You might prefer &man.cpio.1;, &man.pax.1;, &man.tar.1; to &man.dump.8; for user data. At the time of this writing, these are known to lose file flag information, so use them with caution. Will a dangerously dedicated disk endanger my health? The installation procedure allows you to chose two different methods in partitioning your hard disk(s). The default way makes it compatible with other operating systems on the same machine, by using fdisk table entries (called slices in FreeBSD), with a FreeBSD slice that employs partitions of its own. Optionally, one can chose to install a boot-selector to switch between the possible operating systems on the disk(s). The alternative uses the entire disk for FreeBSD, and makes no attempt to be compatible with other operating systems. So why it is called dangerous? A disk in this mode does not contain what normal PC utilities would consider a valid fdisk table. Depending on how well they have been designed, they might complain at you once they are getting in contact with such a disk, or even worse, they might damage the BSD bootstrap without even asking or notifying you. In addition, the dangerously dedicated disk's layout is known to confuse many BIOSes, including those from AWARD (e.g. as found in HP Netserver and Micronics systems as well as many others) and Symbios/NCR (for the popular 53C8xx range of SCSI controllers). This is not a complete list, there are more. Symptoms of this confusion include the read error message printed by the FreeBSD bootstrap when it cannot find itself, as well as system lockups when booting. Why have this mode at all then? It only saves a few kbytes of disk space, and it can cause real problems for a new installation. Dangerously dedicated mode's origins lie in a desire to avoid one of the most common problems plaguing new FreeBSD installers - matching the BIOS geometry numbers for a disk to the disk itself. Geometry is an outdated concept, but one still at the heart of the PC's BIOS and its interaction with disks. When the FreeBSD installer creates slices, it has to record the location of these slices on the disk in a fashion that corresponds with the way the BIOS expects to find them. If it gets it wrong, you will not be able to boot. Dangerously dedicated mode tries to work around this by making the problem simpler. In some cases, it gets it right. But it is meant to be used as a last-ditch alternative - there are better ways to solve the problem 99 times out of 100. So, how do you avoid the need for DD mode when you are installing? Start by making a note of the geometry that your BIOS claims to be using for your disks. You can arrange to have the kernel print this as it boots by specifying at the boot: prompt, or using boot -v in the loader. Just before the installer starts, the kernel will print a list of BIOS geometries. Do not panic - wait for the installer to start and then use scrollback to read the numbers. Typically the BIOS disk units will be in the same order that FreeBSD lists your disks, first IDE, then SCSI. When you are slicing up your disk, check that the disk geometry displayed in the FDISK screen is correct (ie. it matches the BIOS numbers); if it is wrong, use the g key to fix it. You may have to do this if there is absolutely nothing on the disk, or if the disk has been moved from another system. Note that this is only an issue with the disk that you are going to boot from; FreeBSD will sort itself out just fine with any other disks you may have. Once you have got the BIOS and FreeBSD agreeing about the geometry of the disk, your problems are almost guaranteed to be over, and with no need for DD mode at all. If, however, you are still greeted with the dreaded read error message when you try to boot, it is time to cross your fingers and go for it - there is nothing left to lose. To return a dangerously dedicated disk for normal PC use, there are basically two options. The first is, you write enough NULL bytes over the MBR to make any subsequent installation believe this to be a blank disk. You can do this for example with &prompt.root; dd if=/dev/zero of=/dev/rda0 count=15 Alternatively, the undocumented DOS feature C:\> fdisk /mbr will to install a new master boot record as well, thus clobbering the BSD bootstrap. Which partitions can safely use Soft Updates? I have heard that Soft Updates on / can cause problems. Short answer: you can usually use Soft Updates safely on all partitions. Long answer: There used to be some concern over using Soft Updates on the root partition. Soft Updates has two characteristics that caused this. First, a Soft Updates partition has a small chance of losing data during a system crash. (The partition will not be corrupted; the data will simply be lost.) Also, Soft Updates can cause temporary space shortages. When using Soft Updates, the kernel can take up to thirty seconds to actually write changes to the physical disk. If you delete a large file, the file still resides on disk until the kernel actually performs the deletion. This can cause a very simple race condition. Suppose you delete one large file and immediately create another large file. The first large file is not yet actually removed from the physical disk, so the disk might not have enough room for the second large file. You get an error that the partition does not have enough space, although you know perfectly well that you just released a large chunk of space! When you try again mere seconds later, the file creation works as you expect. This has left more than one user scratching his head and doubting his sanity, the FreeBSD filesystem, or both. If a system should crash after the kernel accepts a chunk of data for writing to disk, but before that data is actually written out, data could be lost or corrupted. This risk is extremely small, but generally manageable. Use of IDE write caching greatly increases this risk; it is strongly recommended that you disable IDE write caching when using Soft Updates. These issues affect all partitions using Soft Updates. So, what does this mean for the root partition? Vital information on the root partition changes very rarely. Files such as /kernel and the contents of /etc only change during system maintenance, or when users change their passwords. If the system crashed during the thirty-second window after such a change is made, it is possible that data could be lost. This risk is negligible for most applications, but you should be aware that it exists. If your system cannot tolerate this much risk, do not use Soft Updates on the root filesystem! / is traditionally one of the smallest partitions. By default, FreeBSD puts the /tmp directory on /. If you have a busy /tmp, you might see intermittent space problems. Symlinking /tmp to /var/tmp will solve this problem. What is inappropriate about my ccd? The symptom of this is: &prompt.root; ccdconfig -C ccdconfig: ioctl (CCDIOCSET): /dev/ccd0c: Inappropriate file type or format This usually happens when you are trying to concatenate the c partitions, which default to type unused. The ccd driver requires the underlying partition type to be FS_BSDFFS. Edit the disklabel of the disks you are trying to concatenate and change the types of partitions to 4.2BSD. Why can I not edit the disklabel on my ccd? The symptom of this is: &prompt.root; disklabel ccd0 (it prints something sensible here, so let us try to edit it) &prompt.root; disklabel -e ccd0 (edit, save, quit) disklabel: ioctl DIOCWDINFO: No disk label on disk; use "disklabel -r" to install initial label This is because the disklabel returned by ccd is actually a fake one that is not really on the disk. You can solve this problem by writing it back explicitly, as in: &prompt.root; disklabel ccd0 > /tmp/disklabel.tmp &prompt.root; disklabel -Rr ccd0 /tmp/disklabel.tmp &prompt.root; disklabel -e ccd0 (this will work now) Can I mount other foreign filesystems under FreeBSD? Digital UNIX UFS CDROMs can be mounted directly on FreeBSD. Mounting disk partitions from Digital UNIX and other systems that support UFS may be more complex, depending on the details of the disk partitioning for the operating system in question. Linux FreeBSD supports ext2fs partitions. See &man.mount.ext2fs.8; for more information. NT FreeBSD includes a read-only NTFS driver. For more information, see &man.mount.ntfs.8;. Any other information on this subject would be appreciated. How do I mount a secondary DOS partition? The secondary DOS partitions are found after ALL the primary partitions. For example, if you have an E partition as the second DOS partition on the second SCSI drive, you need to create the special files for slice 5 in /dev, then mount /dev/da1s5: &prompt.root; cd /dev &prompt.root; sh MAKEDEV da1s5 &prompt.root; mount -t msdos /dev/da1s5 /dos/e You can omit this step if you are running FreeBSD 5.0-RELEASE or newer with &man.devfs.5; enabled. Is there a cryptographic filesystem for &os;? Yes; see the security/cfs port. How can I use the NT loader to boot FreeBSD? The general idea is that you copy the first sector of your native root FreeBSD partition into a file in the DOS/NT partition. Assuming you name that file something like c:\bootsect.bsd (inspired by c:\bootsect.dos), you can then edit the c:\boot.ini file to come up with something like this: [boot loader] timeout=30 default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS [operating systems] multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows NT" C:\BOOTSECT.BSD="FreeBSD" C:\="DOS" If FreeBSD is installed on the same disk as the NT boot partition simply copy /boot/boot1 to C:\BOOTSECT.BSD However, if FreeBSD is installed on a different disk /boot/boot1 will not work, /boot/boot0 is needed. DO NOT SIMPLY COPY /boot/boot0 INSTEAD OF /boot/boot1, YOU WILL OVERWRITE YOUR PARTITION TABLE AND RENDER YOUR COMPUTER UN-BOOTABLE! /boot/boot0 needs to be installed using sysinstall by selecting the FreeBSD boot manager on the screen which asks if you wish to use a boot manager. This is because /boot/boot0 has the partition table area filled with NULL characters but sysinstall copies the partition table before copying /boot/boot0 to the MBR. When the FreeBSD boot manager runs it records the last OS booted by setting the active flag on the partition table entry for that OS and then writes the whole 512-bytes of itself back to the MBR so if you just copy /boot/boot0 to C:\BOOTSECT.BSD then it writes an empty partition table, with the active flag set on one entry, to the MBR. How do I boot FreeBSD and Linux from LILO? If you have FreeBSD and Linux on the same disk, just follow LILO's installation instructions for booting a non-Linux operating system. Very briefly, these are: Boot Linux, and add the following lines to /etc/lilo.conf: other=/dev/hda2 table=/dev/hda label=FreeBSD (the above assumes that your FreeBSD slice is known to Linux as /dev/hda2; tailor to suit your setup). Then, run lilo as root and you should be done. If FreeBSD resides on another disk, you need to add loader=/boot/chain.b to the LILO entry. For example: other=/dev/dab4 table=/dev/dab loader=/boot/chain.b label=FreeBSD In some cases you may need to specify the BIOS drive number to the FreeBSD boot loader to successfully boot off the second disk. For example, if your FreeBSD SCSI disk is probed by BIOS as BIOS disk 1, at the FreeBSD boot loader prompt you need to specify: Boot: 1:da(0,a)/kernel On FreeBSD 2.2.5 and later, you can configure &man.boot.8; to automatically do this for you at boot time. The Linux+FreeBSD mini-HOWTO is a good reference for FreeBSD and Linux interoperability issues. How do I boot FreeBSD and Linux using BootEasy? Install LILO at the start of your Linux boot partition instead of in the Master Boot Record. You can then boot LILO from BootEasy. If you are running Windows 95 and Linux this is recommended anyway, to make it simpler to get Linux booting again if you should need to reinstall Windows 95 (which is a Jealous Operating System, and will bear no other Operating Systems in the Master Boot Record). How do I change the boot prompt from ??? to something more meaningful? You can not do that with the standard boot manager without rewriting it. There are a number of other boot managers in the sysutils ports category that provide this functionality. I have a new removable drive, how do I use it? Whether it is a removable drive like a ZIP or an EZ drive (or even a floppy, if you want to use it that way), or a new hard disk, once it is installed and recognized by the system, and you have your cartridge/floppy/whatever slotted in, things are pretty much the same for all devices. (this section is based on Mark Mayo's ZIP FAQ) If it is a ZIP drive or a floppy, you have already got a DOS filesystem on it, you can use a command like this: &prompt.root; mount -t msdos /dev/fd0c /floppy if it is a floppy, or this: &prompt.root; mount -t msdos /dev/da2s4 /zip for a ZIP disk with the factory configuration. For other disks, see how they are laid out using &man.fdisk.8; or &man.sysinstall.8;. The rest of the examples will be for a ZIP drive on da2, the third SCSI disk. Unless it is a floppy, or a removable you plan on sharing with other people, it is probably a better idea to stick a BSD filesystem on it. You will get long filename support, at least a 2X improvement in performance, and a lot more stability. First, you need to redo the DOS-level partitions/filesystems. You can either use &man.fdisk.8; or /stand/sysinstall, or for a small drive that you do not want to bother with multiple operating system support on, just blow away the whole FAT partition table (slices) and just use the BSD partitioning: &prompt.root; dd if=/dev/zero of=/dev/rda2 count=2 &prompt.root; disklabel -Brw da2 auto You can use disklabel or /stand/sysinstall to create multiple BSD partitions. You will certainly want to do this if you are adding swap space on a fixed disk, but it is probably irrelevant on a removable drive like a ZIP. Finally, create a new filesystem, this one is on our ZIP drive using the whole disk: &prompt.root; newfs /dev/rda2c and mount it: &prompt.root; mount /dev/da2c /zip and it is probably a good idea to add a line like this to /etc/fstab (see &man.fstab.5;) so you can just type mount /zip in the future: /dev/da2c /zip ffs rw,noauto 0 0 Why do I get Incorrect super block when mounting a CDROM? You have to tell &man.mount.8; the type of the device that you want to mount. This is described in the Handbook section on optical media, specifically the section Using Data CDs. Why do I get Device not configured when mounting a CDROM? This generally means that there is no CDROM in the CDROM drive, or the drive is not visible on the bus. Please see the Using Data CDs section of the Handbook for a detailed discussion of this issue. Why do all non-English characters in filenames show up as ? on my CDs when mounted in FreeBSD? Your CDROM probably uses the Joliet extension for storing information about files and directories. This is discussed in the Handbook chapter on creating and using CDROMs, specifically the section on Using Data CDROMs. I burned a CD under FreeBSD and now I can not read it under any other operating system. Why? You most likely burned a raw file to your CD, rather than creating an ISO 9660 filesystem. Take a look at the Handbook chapter on creating CDROMs, particularly the section on burning raw data CDs. How can I create an image of a data CD? This is discussed in the Handbook section on duplicating data CDs. For more on working with CDROMs, see the Creating CDs Section in the Storage chapter in the Handbook. Why can I not mount an audio CD? If you try to mount an audio CD, you will get an error like cd9660: /dev/acd0c: Invalid argument. This is because mount only works on filesystems. Audio CDs do not have filesystems; they just have data. You need a program that reads audio CDs, such as the audio/xmcd port. How do I mount a multi-session CD? By default, &man.mount.8; will attempt to mount the last data track (session) of a CD. If you would like to load an earlier session, you must use the command line argument. Please see &man.mount.cd9660.8; for specific examples. How do I let ordinary users mount floppies, CDROMs and other removable media? Ordinary users can be permitted to mount devices. Here is how: As root set the sysctl variable vfs.usermount to 1. &prompt.root; sysctl -w vfs.usermount=1 As root assign the appropriate permissions to the block device associated with the removable media. For example, to allow users to mount the first floppy drive, use: &prompt.root; chmod 666 /dev/fd0 To allow users in the group operator to mount the CDROM drive, use: &prompt.root; chgrp operator /dev/cd0c &prompt.root; chmod 640 /dev/cd0c Finally, add the line vfs.usermount=1 to the file /etc/sysctl.conf so that it is reset at system boot time. All users can now mount the floppy /dev/fd0 onto a directory that they own: &prompt.user; mkdir ~/my-mount-point &prompt.user; mount -t msdos /dev/fd0 ~/my-mount-point Users in group operator can now mount the CDROM /dev/cd0c onto a directory that they own: &prompt.user; mkdir ~/my-mount-point &prompt.user; mount -t cd9660 /dev/cd0c ~/my-mount-point Unmounting the device is simple: &prompt.user; umount ~/my-mount-point Enabling vfs.usermount, however, has negative security implications. A better way to access MSDOS formatted media is to use the mtools package in the ports collection. The du and df commands show different amounts of disk space available. What is going on? You need to understand what du and df really do. du goes through the directory tree, measures how large each file is, and presents the totals. df just asks the filesystem how much space it has left. They seem to be the same thing, but a file without a directory entry will affect df but not du. When a program is using a file, and you delete the file, the file is not really removed from the filesystem until the program stops using it. The file is immediately deleted from the directory listing, however. You can see this easily enough with a program such as more. Assume you have a file large enough that its presence affects the output of du and df. (Since disks can be so large today, this might be a very large file!) If you delete this file while using more on it, more does not immediately choke and complain that it cannot view the file. The entry is simply removed from the directory so no other program or user can access it. du shows that it is gone — it has walked the directory tree and the file is not listed. df shows that it is still there, as the filesystem knows that more is still using that space. Once you end the more session, du and df will agree. Note that Soft Updates can delay the freeing of disk space; you might need to wait up to 30 seconds for the change to be visible! This situation is common on web servers. Many people set up a FreeBSD web server and forget to rotate the log files. The access log fills up /var. The new administrator deletes the file, but the system still complains that the partition is full. Stopping and restarting the web server program would free the file, allowing the system to release the disk space. To prevent this from happening, set up &man.newsyslog.8;. How can I add more swap space? In the Configuration and Tuning section of the Handbook, you will find a section describing how to do this. How is it possible for a partition to be more than 100% full? A portion of each UFS partition (8%, by default) is reserved for use by the operating system and the root user. &man.df.1; does not count that space when calculating the Capacity column, so it can exceed 100%. Also, you'll notice that the Blocks column is always greater than the sum of the Used and Avail columns, usually by a factor of 8%. For more details, look up the option in &man.tunefs.8;. System Administration Where are the system start-up configuration files? The primary configuration file is /etc/defaults/rc.conf (see &man.rc.conf.5;) System startup scripts such as /etc/rc and /etc/rc.d (see &man.rc.8;) just include this file. Do not edit this file! Instead, if there is any entry in /etc/defaults/rc.conf that you want to change, you should copy the line into /etc/rc.conf and change it there. For example, if you wish to start named, the included DNS server, all you need to do is: &prompt.root; echo named_enable="YES" >> /etc/rc.conf To start up local services, place shell scripts in the /usr/local/etc/rc.d directory. These shell scripts should be set executable, and end with a .sh. How do I add a user easily? Use the &man.adduser.8; command, or the &man.pw.8; command for more complicated situations. To remove the user, use the &man.rmuser.8; command or, if necessary, &man.pw.8;. Why do I keep getting messages like root: not found after editing my crontab file? This is normally caused by editing the system crontab (/etc/crontab) and then using &man.crontab.1; to install it: &prompt.root; crontab /etc/crontab This is not the correct way to do things. The system crontab has a different format to the per-user crontabs which &man.crontab.1; updates (the &man.crontab.5; manual page explains the differences in more detail). If this is what you did, the extra crontab is simply a copy of /etc/crontab in the wrong format it. Delete it with the command: &prompt.root; crontab -r Next time, when you edit /etc/crontab, you should not do anything to inform &man.cron.8; of the changes, since it will notice them automatically. If you want something to be run once per day, week, or month, it is probably better to add shell scripts /usr/local/etc/periodic, and let the &man.periodic.8; command run from the system cron schedule it with the other periodic system tasks. The actual reason for the error is that the system crontab has an extra field, specifying which user to run the command as. In the default system crontab provided with FreeBSD, this is root for all entries. When this crontab is used as the root user's crontab (which is not the same as the system crontab), &man.cron.8; assumes the string root is the first word of the command to execute, but no such command exists. Why do I get the error, you are not in the correct group to su root when I try to su to root? This is a security feature. In order to su to root (or any other account with superuser privileges), you must be in the wheel group. If this feature were not there, anybody with an account on a system who also found out root's password would be able to gain superuser level access to the system. With this feature, this is not strictly true; &man.su.1; will prevent them from even trying to enter the password if they are not in wheel. To allow someone to su to root, simply put them in the wheel group. I made a mistake in rc.conf, or another startup file, and now I cannot edit it because the filesystem is read-only. What should I do? When you get the prompt to enter the shell pathname, simply press ENTER, and run mount / to re-mount the root filesystem in read/write mode. You may also need to run mount -a -t ufs to mount the filesystem where your favourite editor is defined. If your favourite editor is on a network filesystem, you will need to either configure the network manually before you can mount network filesystems, or use an editor which resides on a local filesystem, such as &man.ed.1;. If you intend to use a full screen editor such as &man.vi.1; or &man.emacs.1;, you may also need to run export TERM=cons25 so that these editors can load the correct data from the &man.termcap.5; database. Once you have performed these steps, you can edit /etc/rc.conf as you usually would to fix the syntax error. The error message displayed immediately after the kernel boot messages should tell you the number of the line in the file which is at fault. Why am I having trouble setting up my printer? Please have a look at the Handbook entry on printing. It should cover most of your problem. See the Handbook entry on printing. Some printers require a host-based driver to do any kind of printing. These so-called WinPrinters are not natively supported by FreeBSD. If your printer does not work in DOS or Windows NT 4.0, it is probably a WinPrinter. Your only hope of getting one of these to work is to check if the print/pnm2ppa port supports it. How can I correct the keyboard mappings for my system? Please see the Handbook section on using localization, specifically the section on console setup. Why do I get messages like: unknown: <PNP0303> can't assign resources on boot? The following is an excerpt from a post to the freebsd-current mailing list.
&a.wollman;, 24 April 2001 The can't assign resources messages indicate that the devices are legacy ISA devices for which a non-PnP-aware driver is compiled into the kernel. These include devices such as keyboard controllers, the programmable interrupt controller chip, and several other bits of standard infrastructure. The resources cannot be assigned because there is already a driver using those addresses.
Why can I not get user quotas to work properly? Do not turn on quotas on /, Put the quota file on the filesystem that the quotas are to be enforced on. ie: Filesystem Quota file /usr /usr/admin/quotas /home /home/admin/quotas … … Does FreeBSD support System V IPC primitives? Yes, FreeBSD supports System V-style IPC, including shared memory, messages and semaphores. Versions of FreeBSD later than 3.2 support System V IPC in the GENERIC kernel. In earlier versions of FreeBSD, enable this support by adding the following lines to your kernel config. options SYSVSHM # enable shared memory options SYSVSEM # enable for semaphores options SYSVMSG # enable for messaging Recompile and install your kernel. What other mail-server software can I use, instead of Sendmail? Sendmail is the default mail-server software for FreeBSD, but you can easily replace it with one of the other MTA (for instance, an MTA installed from the ports). There are various alternative MTA's in the ports tree already, with mail/exim, mail/postfix, mail/qmail, mail/zmailer, being some of the most popular choices. Diversity is nice, and the fact that you have many different mail-servers to chose from is considered a good thing; therefore try to avoid asking questions like Is Sendmail better than Qmail? in the mailing lists. If you do feel like asking, first check the mailing list archives. The advantages and disadvantages of each and every one of the available MTA's have already been discussed a few times. I have forgotten the root password! What do I do? Do not Panic! Simply restart the system, type boot -s at the Boot: prompt (just -s for FreeBSD releases before 3.2) to enter Single User mode. At the question about the shell to use, hit ENTER. You will be dropped to a &prompt.root; prompt. Enter mount -u / to remount your root filesystem read/write, then run mount -a to remount all the filesystems. Run passwd root to change the root password then run &man.exit.1; to continue booting. How do I keep ControlAltDelete from rebooting the system? If you are using syscons (the default console driver) build and install a new kernel with the following option. options SC_DISABLE_REBOOT in the configuration file. If you use the PCVT console driver, use the following kernel configuration line instead. options PCVT_CTRL_ALT_DEL How do I reformat DOS text files to Unix ones? Simply use this perl command: &prompt.user; perl -i.bak -npe 's/\r\n/\n/g' file ... file is the file(s) to process. The modification is done in-place, with the original file stored with a .bak extension. Alternatively you can use the &man.tr.1; command: &prompt.user; tr -d '\r' < dos-text-file > unix-file dos-text-file is the file containing DOS text while unix-file will contain the converted output. This can be quite a bit faster than using perl. How do I kill processes by name? Use &man.killall.1;. Why is su bugging me about not being in root's ACL? The error comes from the Kerberos distributed authentication system. The problem is not fatal but annoying. You can either run su with the -K option, or uninstall Kerberos as described in the next question. How do I uninstall Kerberos? To remove Kerberos from the system, reinstall the bin distribution for the release you are running. If you have the CDROM, you can mount the cd (we will assume on /cdrom) and run &prompt.root; cd /cdrom/bin &prompt.root; ./install.sh Alternately, you can remove all MAKE_KERBEROS options from /etc/make.conf and rebuild world. What happened to /dev/MAKEDEV? FreeBSD 5.X uses the &man.devfs.8; device-on-demand system. Device drivers automatically create new device nodes as they are needed, obsoleting /dev/MAKEDEV. If you are running FreeBSD 4.X or earlier and /dev/MAKEDEV is missing, then you really do have a problem. Grab a copy from the system source code, probably in /usr/src/etc/MAKEDEV. How do I add pseudoterminals to the system? If you have lots of telnet, ssh, X, or screen users, you will probably run out of pseudoterminals. Here is how to add more: Build and install a new kernel with the line pseudo-device pty 256 in the configuration file. Run the commands &prompt.root; cd /dev &prompt.root; sh MAKEDEV pty{1,2,3,4,5,6,7} to make 256 device nodes for the new terminals. Edit /etc/ttys and add lines for each of the 256 terminals. They should match the form of the existing entries, i.e. they look like ttyqc none network The order of the letter designations is tty[pqrsPQRS][0-9a-v], using a regular expression. Reboot the system with the new kernel and you are ready to go. Why can I not create the snd0 device? There is no snd device. The name is used as a shorthand for the various devices that make up the FreeBSD sound driver, such as mixer, sequencer, and dsp. To create these devices you should &prompt.root; cd /dev &prompt.root; sh MAKEDEV snd0 You can omit this step if you are running FreeBSD 5.0-RELEASE or newer with &man.devfs.5; enabled. How do I re-read /etc/rc.conf and re-start /etc/rc without a reboot? Go into single user mode and then back to multi user mode. On the console do: &prompt.root; shutdown now (Note: without -r or -h) &prompt.root; return &prompt.root; exit I tried to update my system to the latest -STABLE, but got -RC or -PRERELEASE! What is going on? Short answer: it is just a name. RC stands for Release Candidate. It signifies that a release is imminent. In FreeBSD, -PRERELEASE is typically synonymous with the code freeze before a release. (For some releases, the -BETA label was used in the same way as -PRERELEASE.) Long answer: FreeBSD derives its releases from one of two places. Major, dot-zero, releases, such as 3.0-RELEASE and 4.0-RELEASE, are branched from the head of the development stream, commonly referred to as -CURRENT. Minor releases, such as 3.1-RELEASE or 4.2-RELEASE, have been snapshots of the active -STABLE branch. Starting with 4.3-RELEASE, each release also now has its own branch which can be tracked by people requiring an extremely conservative rate of development (typically only security advisories). When a release is about to be made, the branch from which it will be derived from has to undergo a certain process. Part of this process is a code freeze. When a code freeze is initiated, the name of the branch is changed to reflect that it is about to become a release. For example, if the branch used to be called 4.5-STABLE, its name will be changed to 4.6-PRERELEASE to signify the code freeze and signify that extra pre-release testing should be happening. Bug fixes can still be committed to be part of the release. When the source code is in shape for the release the name will be changed to 4.6-RC to signify that a release is about to be made from it. Once in the RC stage, only the most critical bugs found can be fixed. Once the release (4.6-RELEASE in this example) and release branch have been made, the branch will be renamed to 4.6-STABLE. For more information on version numbers and the various CVS branches, refer to the Release Engineering article. I tried to install a new kernel, and the chflags failed. How do I get around this? Short answer: You are probably at security level greater than 0. Reboot directly to single user mode to install the kernel. Long answer: FreeBSD disallows changing system flags at security levels greater than 0. You can check your security level with the command: &prompt.root; sysctl kern.securelevel You cannot lower the security level; you have to boot to single mode to install the kernel, or change the security level in /etc/rc.conf then reboot. See the &man.init.8; manual page for details on securelevel, and see /etc/defaults/rc.conf and the &man.rc.conf.5; manual page for more information on rc.conf. I cannot change the time on my system by more than one second! How do I get around this? Short answer: You are probably at security level greater than 1. Reboot directly to single user mode to change the date. Long answer: FreeBSD disallows changing the time by more that one second at security levels greater than 1. You can check your security level with the command: &prompt.root; sysctl kern.securelevel You cannot lower the security level; you have to boot to single mode to change the date, or change the security level in /etc/rc.conf then reboot. See the &man.init.8; manual page for details on securelevel, and see /etc/defaults/rc.conf and the &man.rc.conf.5; manual page for more information on rc.conf. Why is rpc.statd using 256 megabytes of memory? No, there is no memory leak, and it is not using 256 Mbytes of memory. It simply likes to (i.e., always does) map an obscene amount of memory into its address space for convenience. There is nothing terribly wrong with this from a technical standpoint; it just throws off things like &man.top.1; and &man.ps.1;. &man.rpc.statd.8; maps its status file (resident on /var) into its address space; to save worrying about remapping it later when it needs to grow, it maps it with a generous size. This is very evident from the source code, where one can see that the length argument to &man.mmap.2; is 0x10000000, or one sixteenth of the address space on an IA32, or exactly 256MB. Why can I not unset the schg file flag? You are running at an elevated (i.e., greater than 0) securelevel. Lower the securelevel and try again. For more information, see the FAQ entry on securelevel and the &man.init.8; manual page. Why does SSH authentication through .shosts not work by default in recent versions of FreeBSD? The reason why .shosts authentication does not work by default in more recent versions of FreeBSD is because &man.ssh.1; is not installed suid root by default. To fix this, you can do one of the following: As a permanent fix, set ENABLE_SUID_SSH to true in /etc/make.conf and rebuild ssh (or run make world). As a temporary fix, change the mode on /usr/bin/ssh to 4555 by running chmod 4555 /usr/bin/ssh as root. Then add ENABLE_SUID_SSH= true to /etc/make.conf so the change takes effect the next time make world is run. What is vnlru? vnlru flushes and frees vnodes when the system hits the kern.maxvnodes limit. This kernel thread sits mostly idle, and only activates if you have a huge amount of RAM and are accessing tens of thousands of tiny files. What do the various memory states displayed by top mean? Active: pages recently statistically used. Inactive: pages recently statistically unused. Cache: (most often) pages that have percolated from inactive to a status where they maintain their data, but can often be immediately reused (either with their old association, or reused with a new association.) There can be certain immediate transition from active to 'cache' state if the page is known to be clean (unmodified), but that transition is a matter of policy, depending upon the algorithm choice of the VM system maintainer. Free: pages without data content, and can be immediately used in certain circumstances where cache pages might be ineligible. Free pages can be reused at interrupt or process state. Wired: pages that are fixed into memory, usually for kernel purposes, but also sometimes for special use in processes. Pages are most often written to disk (sort of a VM sync) when they are in the 'inactive' state, but 'active' pages can also be synced also (but requires the availability of certain CPU features.) This depends upon the CPU tracking of the 'modified' bit being available, and in certain situations there can be an advantage for a block of VM pages to be synced, whether they are active or inactive. In most common cases, it is best to think of the 'inactive' queue to be a queue of relatively unused pages that might or might not be in the process of being written to disk. 'Cached' pages are already 'synced', not mapped, but available for immediate process use with their old association or with a new association. Free pages are available at interrupt level, but cached or free pages can be used at process state for reuse. Cache pages aren't adequately locked to be available at interrupt level. There are some other flags (e.g. Busy flag or busy count) that might modify some of the rules that I described. How much free memory is available? There are a couple of kinds of free memory. One kind is the amount of memory immediately available without paging anything else out. That is approximately the size of cache queue + size of free queue (with a derating factor, depending upon system tuning.) Another kind of free memory is the total amount of VM space. That can be complex, but is dependent upon the amount of swap space and memory. Other kinds of free memory descriptions are also possible, but it is relatively useless to define these, but rather it is important to make sure that the paging rate is kept low, and to avoid running out of swap space. What is /var/empty? I can not delete it! /var/empty is a directory that the &man.sshd.8; program uses when performing privilege separation. The /var/empty directory is empty, owned by root and has the schg flag set. Although it is not recommended to delete this directory, to do so you will need to unset the schg flag first. See the &man.chflags.1; manual page for more information (and bear in mind the answer to the question on unsetting the schg flag). The X Window System and Virtual Consoles I want to run X, how do I go about it? The easiest way is to simply specify that you want to run X during the installation process. Then read and follow the documentation on the xf86config tool, which assists you in configuring XFree86 for your particular graphics card/mouse/etc. You may also wish to investigate the Xaccel server. See the section on Xi Graphics or Metro Link for more details. I tried to run X, but I get an KDENABIO failed (Operation not permitted) error when I type startx. What do I do now? Your system is running at a raised securelevel, is not it? It is, indeed, impossible to start X at a raised securelevel. To see why, look at the &man.init.8; man page. So the question is what else you should do instead, and you basically have two choices: set your securelevel back down to zero (usually from /etc/rc.conf), or run &man.xdm.1; at boot time (before the securelevel is raised). See for more information about running &man.xdm.1; at boot time. Why does my mouse not work with X? If you are using syscons (the default console driver), you can configure FreeBSD to support a mouse pointer on each virtual screen. In order to avoid conflicting with X, syscons supports a virtual device called /dev/sysmouse. All mouse events received from the real mouse device are written to the sysmouse device via moused. If you wish to use your mouse on one or more virtual consoles, and use X, see and set up moused. Then edit /etc/XF86Config and make sure you have the following lines. Section Pointer Protocol "SysMouse" Device "/dev/sysmouse" ..... The above example is for XFree86 3.3.2 or later. For earlier versions, the Protocol should be MouseSystems. Some people prefer to use /dev/mouse under X. To make this work, /dev/mouse should be linked to /dev/sysmouse (see &man.sysmouse.4;): &prompt.root; cd /dev &prompt.root; rm -f mouse &prompt.root; ln -s sysmouse mouse My mouse has a fancy wheel. Can I use it in X? Yes. But you need to customize X client programs. See Colas Nahaboo's web page (http://www.inria.fr/koala/colas/mouse-wheel-scroll/) . If you want to use the imwheel program, just follow these simple steps. Translate the Wheel Events The imwheel program works by translating mouse button 4 and mouse button 5 events into key events. Thus, you have to get the mouse driver to translate mouse wheel events to button 4 and 5 events. There are two ways of doing this, the first way is to have &man.moused.8; do the translation. The second way is for the X server itself to do the event translation. Using &man.moused.8; to Translate Wheel Events To have &man.moused.8; perform the event translations, simply add to the command line used to start &man.moused.8;. For example, if you normally start &man.moused.8; via moused -p /dev/psm0 you would start it by entering moused -p /dev/psm0 -z 4 instead. If you start &man.moused.8; automatically during bootup via /etc/rc.conf, you can simply add to the moused_flags variable in /etc/rc.conf. You now need to tell X that you have a 5 button mouse. To do this, simply add the line Buttons 5 to the Pointer section of /etc/XF86Config. For example, you might have the following Pointer section in /etc/XF86Config. <quote>Pointer</quote> Section for Wheeled Mouse in XFree86 3.3.x series XF86Config with moused Translation Section "Pointer" Protocol "SysMouse" Device "/dev/sysmouse" Buttons 5 EndSection <quote>InputDevice</quote> Section for Wheeled Mouse in XFree86 4.x series XF86Config with X Server Translation Section "InputDevice" Identifier "Mouse1" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/sysmouse" Option "Buttons" "5" EndSection <quote>.emacs</quote> example for naive page scrolling with Wheeled Mouse ;; wheel mouse (global-set-key [mouse-4] 'scroll-down) (global-set-key [mouse-5] 'scroll-up) Using Your X Server to Translate the Wheel Events If you are not running &man.moused.8;, or if you do not want &man.moused.8; to translate your wheel events, you can have the X server do the event translation instead. This requires a couple of modifications to your /etc/XF86Config file. First, you need to choose the proper protocol for your mouse. Most wheeled mice use the IntelliMouse protocol. However, XFree86 does support other protocols, such as MouseManPlusPS/2 for the Logitech MouseMan+ mice. Once you have chosen the protocol you will use, you need to add a Protocol line to the Pointer section. Secondly, you need to tell the X server to remap wheel scroll events to mouse buttons 4 and 5. This is done with the ZAxisMapping option. For example, if you are not using &man.moused.8;, and you have an IntelliMouse attached to the PS/2 mouse port you would use the following in /etc/XF86Config. <quote>Pointer</quote> Section for Wheeled Mouse in <filename>XF86Config</filename> with X Server Translation Section "Pointer" Protocol "IntelliMouse" Device "/dev/psm0" ZAxisMapping 4 5 EndSection <quote>InputDevice</quote> Section for Wheeled Mouse in XFree86 4.x series XF86Config with X Server Translation Section "InputDevice" Identifier "Mouse1" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psm0" Option "ZAxisMapping" "4 5" EndSection <quote>.emacs</quote> example for naive page scrolling with Wheeled Mouse ;; wheel mouse (global-set-key [mouse-4] 'scroll-down) (global-set-key [mouse-5] 'scroll-up) Install imwheel Next, install imwheel from the Ports collection. It can be found in the x11 category. This program will map the wheel events from your mouse into keyboard events. For example, it might send Page Up to a program when you scroll the wheel forwards. Imwheel uses a configuration file to map the wheel events to key presses so that it can send different keys to different applications. The default imwheel configuration file is installed in /usr/X11R6/etc/imwheelrc. You can copy it to ~/.imwheelrc and then edit it if you wish to customize imwheel's configuration. The format of the configuration file is documented in &man.imwheel.1;. Configure Emacs to Work with Imwheel (optional) If you use emacs or XEmacs, then you need to add a small section to your ~/.emacs file. For emacs, add the following: <application>Emacs</application> Configuration for <application>Imwheel</application> ;;; For imwheel (setq imwheel-scroll-interval 3) (defun imwheel-scroll-down-some-lines () (interactive) (scroll-down imwheel-scroll-interval)) (defun imwheel-scroll-up-some-lines () (interactive) (scroll-up imwheel-scroll-interval)) (global-set-key [?\M-\C-\)] 'imwheel-scroll-up-some-lines) (global-set-key [?\M-\C-\(] 'imwheel-scroll-down-some-lines) ;;; end imwheel section For XEmacs, add the following to your ~/.emacs file instead: <application>XEmacs</application> Configuration for <application>Imwheel</application> ;;; For imwheel (mwheel-install) (setq mwheel-follow-mouse t) ;;; end imwheel section Run Imwheel You can just type imwheel in an xterm to start it up once it is installed. It will background itself and take effect immediately. If you want to always use imwheel, simply add it to your .xinitrc or .xsession file. You can safely ignore any warnings imwheel displays about PID files. Those warnings only apply to the Linux version of imwheel. How do I use remote X displays? For security reasons, the default setting is to not allow a machine to remotely open a window. To enable this feature, simply start X with the optional argument: &prompt.user; startx -listen_tcp Why do X Window menus and dialog boxes not work right? Try turning off the Num Lock key. If your Num Lock key is on by default at boot-time, you may add the following line in the Keyboard section of the XF86Config file. # Let the server do the NumLock processing. This should only be # required when using pre-R6 clients ServerNumLock What is a virtual console and how do I make more? Virtual consoles, put simply, enable you to have several simultaneous sessions on the same machine without doing anything complicated like setting up a network or running X. When the system starts, it will display a login prompt on the monitor after displaying all the boot messages. You can then type in your login name and password and start working (or playing!) on the first virtual console. At some point, you will probably wish to start another session, perhaps to look at documentation for a program you are running or to read your mail while waiting for an FTP transfer to finish. Just do AltF2 (hold down the Alt key and press the F2 key), and you will find a login prompt waiting for you on the second virtual console! When you want to go back to the original session, do AltF1. The default FreeBSD installation has three virtual consoles enabled (8 starting with 3.3-RELEASE), and AltF1, AltF2, and AltF3 will switch between these virtual consoles. To enable more of them, edit /etc/ttys (see &man.ttys.5;) and add entries for ttyv4 to ttyvc after the comment on Virtual terminals: # Edit the existing entry for ttyv3 in /etc/ttys and change # "off" to "on". ttyv3 "/usr/libexec/getty Pc" cons25 on secure ttyv4 "/usr/libexec/getty Pc" cons25 on secure ttyv5 "/usr/libexec/getty Pc" cons25 on secure ttyv6 "/usr/libexec/getty Pc" cons25 on secure ttyv7 "/usr/libexec/getty Pc" cons25 on secure ttyv8 "/usr/libexec/getty Pc" cons25 on secure ttyv9 "/usr/libexec/getty Pc" cons25 on secure ttyva "/usr/libexec/getty Pc" cons25 on secure ttyvb "/usr/libexec/getty Pc" cons25 on secure Use as many or as few as you want. The more virtual terminals you have, the more resources that are used; this can be important if you have 8MB RAM or less. You may also want to change the secure to insecure. If you want to run an X server you must leave at least one virtual terminal unused (or turned off) for it to use. That is to say that if you want to have a login prompt pop up for all twelve of your Alt-function keys, you are out of luck - you can only do this for eleven of them if you also want to run an X server on the same machine. The easiest way to disable a console is by turning it off. For example, if you had the full 12 terminal allocation mentioned above and you wanted to run X, you would change settings for virtual terminal 12 from: ttyvb "/usr/libexec/getty Pc" cons25 on secure to: ttyvb "/usr/libexec/getty Pc" cons25 off secure If your keyboard has only ten function keys, you would end up with: ttyv9 "/usr/libexec/getty Pc" cons25 off secure ttyva "/usr/libexec/getty Pc" cons25 off secure ttyvb "/usr/libexec/getty Pc" cons25 off secure (You could also just delete these lines.) Once you have edited /etc/ttys, the next step is to make sure that you have enough virtual terminal devices. The easiest way to do this is: &prompt.root; cd /dev &prompt.root; sh MAKEDEV vty12 On FreeBSD 5.x you do not have to create devices manually if you are using DEVFS, since the proper device nodes will be automatically created under /dev. Next, the easiest (and cleanest) way to activate the virtual consoles is to reboot. However, if you really do not want to reboot, you can just shut down the X Window system and execute (as root): &prompt.root; kill -HUP 1 It is imperative that you completely shut down X Window if it is running, before running this command. If you do not, your system will probably appear to hang/lock up after executing the kill command. How do I access the virtual consoles from X? Use Ctrl Alt Fn to switch back to a virtual console. Ctrl Alt F1 would return you to the first virtual console. Once you are back to a text console, you can then use Alt Fn as normal to move between them. To return to the X session, you must switch to the virtual console running X. If you invoked X from the command line, (e.g., using startx) then the X session will attach to the next unused virtual console, not the text console from which it was invoked. If you have eight active virtual terminals then X will be running on the ninth, and you would use Alt F9 to return. How do I start XDM on boot? There are two schools of thought on how to start xdm. One school starts xdm from /etc/ttys (see &man.ttys.5;) using the supplied example, while the other simply runs xdm from rc.local (see &man.rc.8;) or from a X.sh script in /usr/local/etc/rc.d. Both are equally valid, and one may work in situations where the other does not. In both cases the result is the same: X will pop up a graphical login: prompt. The ttys method has the advantage of documenting which vty X will start on and passing the responsibility of restarting the X server on logout to init. The rc.local method makes it easy to kill xdm if there is a problem starting the X server. If loaded from rc.local, xdm should be started without any arguments (i.e., as a daemon). xdm must start AFTER getty runs, or else getty and xdm will conflict, locking out the console. The best way around this is to have the script sleep 10 seconds or so then launch xdm. If you are to start xdm from /etc/ttys, there still is a chance of conflict between xdm and &man.getty.8;. One way to avoid this is to add the vt number in the /usr/X11R6/lib/X11/xdm/Xservers file. :0 local /usr/X11R6/bin/X vt4 The above example will direct the X server to run in /dev/ttyv3. Note the number is offset by one. The X server counts the vty from one, whereas the FreeBSD kernel numbers the vty from zero. Why do I get Couldn't open console when I run xconsole? If you start X with startx, the permissions on /dev/console will not get changed, resulting in things like xterm -C and xconsole not working. This is because of the way console permissions are set by default. On a multi-user system, one does not necessarily want just any user to be able to write on the system console. For users who are logging directly onto a machine with a VTY, the &man.fbtab.5; file exists to solve such problems. In a nutshell, make sure an uncommented line of the form /dev/ttyv0 0600 /dev/console is in /etc/fbtab (see &man.fbtab.5;) and it will ensure that whomever logs in on /dev/ttyv0 will own the console. Before, I was able to run XFree86 as a regular user. Why does it now say that I must be root? All X servers need to be run as root in order to get direct access to your video hardware. Older versions of XFree86 (<= 3.3.6) installed all bundled servers to be automatically run as root (setuid to root). This is obviously a security hazard because X servers are large, complicated programs. Newer versions of XFree86 do not install the servers setuid to root for just this reason. Obviously, running an X server as the root user is not acceptable, nor a good idea security-wise. There are two ways to be able to use X as a regular user. The first is to use xdm or another display manager (e.g., kdm); the second is to use the Xwrapper. xdm is a daemon that handles graphical logins. It is usually started at boot time, and is responsible for authenticating users and starting their sessions; it is essentially the graphical counterpart of &man.getty.8; and &man.login.1;. For more information on xdm see the XFree86 documentation, and the the FAQ entry on it. Xwrapper is the X server wrapper; it is a small utility to enable one to manually run an X server while maintaining reasonable safety. It performs some sanity checks on the command line arguments given, and if they pass, runs the appropriate X server. If you do not want to run a display manger for whatever reason, this is for you. If you have installed the complete ports collection, you can find the port in /usr/ports/x11/wrapper. Why does my PS/2 mouse misbehave under X? Your mouse and the mouse driver may have somewhat become out of synchronization. In rare cases the driver may erroneously report synchronization problem and you may see the kernel message: psmintr: out of sync (xxxx != yyyy) and notice that your mouse does not work properly. If this happens, disable the synchronization check code by setting the driver flags for the PS/2 mouse driver to 0x100. Enter UserConfig by giving the option at the boot prompt: boot: -c Then, in the UserConfig command line, type: UserConfig> flags psm0 0x100 UserConfig> quit Why does my PS/2 mouse from MouseSystems not work? There have been some reports that certain model of PS/2 mouse from MouseSystems works only if it is put into the high resolution mode. Otherwise, the mouse cursor may jump to the upper-left corner of the screen every so often. Specify the flags 0x04 to the PS/2 mouse driver to put the mouse into the high resolution mode. Enter UserConfig by giving the option at the boot prompt: boot: -c Then, in the UserConfig command line, type: UserConfig> flags psm0 0x04 UserConfig> quit See the previous section for another possible cause of mouse problems. When building an X app, imake cannot find Imake.tmpl. Where is it? Imake.tmpl is part of the Imake package, a standard X application building tool. Imake.tmpl, as well as several header files that are required to build X apps, is contained in the X prog distribution. You can install this from sysinstall or manually from the X distribution files. An X app I am building depends on XFree86 3.3.X, but I have XFree86 4.X installed. What should I do? To tell the port build to link to the XFree86 4.X libraries, add the following to /etc/make.conf, (if you do not have this file, create it): XFREE86_VERSION= 4 How do I reverse the mouse buttons? Run the command xmodmap -e "pointer = 3 2 1" from your .xinitrc or .xsession. How do I install a splash screen and where do I find them? Just prior to the release of FreeBSD 3.1, a new feature was added to allow the display of splash screens during the boot messages. The splash screens currently must be a 256 color bitmap (*.BMP) or ZSoft PCX (*.PCX) file. In addition, they must have a resolution of 320x200 or less to work on standard VGA adapters. If you compile VESA support into your kernel, then you can use larger bitmaps up to 1024x768. The actual VESA support can either be compiled directly into the kernel with the VESA kernel config option or by loading the VESA kld module during bootup. To use a splash screen, you need to modify the startup files that control the boot process for FreeBSD. The files for this changed prior to the release of FreeBSD 3.2, so there are now two ways of loading a splash screen: FreeBSD 3.1 The first step is to find a bitmap version of your splash screen. Release 3.1 only supports Windows bitmap splash screens. Once you have found your splash screen of choice copy it to /boot/splash.bmp. Next, you need to have a /boot/loader.rc file that contains the following lines: load kernel load -t splash_image_data /boot/splash.bmp load splash_bmp autoboot FreeBSD 3.2+ In addition to adding support for PCX splash screens, FreeBSD 3.2 includes a nicer way of configuring the boot process. If you wish, you can use the method listed above for FreeBSD 3.1. If you do and you want to use PCX, replace splash_bmp with splash_pcx. If, on the other hand, you want to use the newer boot configuration, you need to create a /boot/loader.rc file that contains the following lines: include /boot/loader.4th start and a /boot/loader.conf that contains the following: splash_bmp_load="YES" bitmap_load="YES" This assumes you are using /boot/splash.bmp for your splash screen. If you would rather use a PCX file, copy it to /boot/splash.pcx, create a /boot/loader.rc as instructed above, and create a /boot/loader.conf that contains: splash_pcx_load="YES" bitmap_load="YES" bitmap_name="/boot/splash.pcx" Now all you need is a splash screen. For that you can surf on over to the gallery at . Can I use the Windows keys on my keyboard in X? Yes. All you need to do is use &man.xmodmap.1; to define what function you wish them to perform. Assuming all Windows keyboards are standard then the keycodes for the 3 keys are 115 - Windows key, between the left-hand Ctrl and Alt keys 116 - Windows key, to the right of the AltGr key 117 - Menu key, to the left of the right-hand Ctrl key To have the left Windows key print a comma, try this. &prompt.root; xmodmap -e "keycode 115 = comma" You will probably have to re-start your window manager to see the result. To have the Windows key-mappings enabled automatically every time you start X either put the xmodmap commands in your ~/.xinitrc file or, preferably, create a file ~/.xmodmaprc and include the xmodmap options, one per line, then add the line xmodmap $HOME/.xmodmaprc to your ~/.xinitrc. For example, you could map the 3 keys to be F13, F14, and F15, respectively. This would make it easy to map them to useful functions within applications or your window manager, as demonstrated further down. To do this put the following in ~/.xmodmaprc. keycode 115 = F13 keycode 116 = F14 keycode 117 = F15 If you use fvwm2, for example, you could map the keys so that F13 iconifies (or de-iconifies) the window the cursor is in, F14 brings the window the cursor is in to the front or, if it is already at the front, pushes it to the back, and F15 pops up the main Workplace (application) menu even if the cursor is not on the desktop, which is useful if you do not have any part of the desktop visible (and the logo on the key matches its functionality). The following entries in ~/.fvwmrc implement the aforementioned setup: Key F13 FTIWS A Iconify Key F14 FTIWS A RaiseLower Key F15 A A Menu Workplace Nop How can I get 3D hardware acceleration for OpenGL? The availability of 3D acceleration depends on the version of XFree86 you are using and the type of video chip you have. If you have an NVIDIA chip, you can use the binary drivers provided for FreeBSD 4.7 on the Drivers section of their website. For other cards with XFree86-4, including the Matrox G200/G400, ATI Rage 128/Radeon, and 3dfx Voodoo 3, 4, 5, and Banshee, information on hardware acceleration is available on the XFree86-4 Direct Rendering on FreeBSD page. Users of XFree86 version 3.3 can use the Utah-GLX port found in graphics/utah-glx to get limited accelerated OpenGL on the Matrox Gx00, ATI Rage Pro, SiS 6326, i810, Savage, and older NVIDIA chips. Networking Where can I get information on diskless booting? Diskless booting means that the FreeBSD box is booted over a network, and reads the necessary files from a server instead of its hard disk. For full details, please read the Handbook entry on diskless booting Can a FreeBSD box be used as a dedicated network router? Yes. Please see the Handbook entry on advanced networking, specifically the section on routing and gateways. Can I connect my Windows box to the Internet via FreeBSD? Typically, people who ask this question have two PC's at home, one with FreeBSD and one with some version of Windows; the idea is to use the FreeBSD box to connect to the Internet and then be able to access the Internet from the Windows box through the FreeBSD box. This is really just a special case of the previous question and works perfectly well. If you're using dialup to connect to the Internet user-mode &man.ppp.8; contains a option. If you run &man.ppp.8; with the option, set gateway_enable to YES in /etc/rc.conf, and configure your Windows machine correctly, this should work fine. For more information, please see the &man.ppp.8; manual page or the Handbook entry on user PPP. If you are using kernel-mode PPP or have an Ethernet connection to the Internet, you need to use &man.natd.8;. Please look at the natd section of the Handbook for a tutorial. Does FreeBSD support SLIP and PPP? Yes. See the manual pages for &man.slattach.8;, &man.sliplogin.8;, &man.ppp.8;, and &man.pppd.8;. &man.ppp.8; and &man.pppd.8; provide support for both incoming and outgoing connections, while &man.sliplogin.8; deals exclusively with incoming connections, and &man.slattach.8; deals exclusively with outgoing connections. For more information on how to use these, please see the Handbook chapter on PPP and SLIP. If you only have access to the Internet through a shell account, you may want to have a look at the net/slirp package. It can provide you with (limited) access to services such as ftp and http direct from your local machine. Does FreeBSD support NAT or Masquerading? Yes. If you want to use NAT over a user PPP connection, please see the Handbook entry on user PPP. If you want to use NAT over some other sort of network connection, please look at the natd section of the Handbook. How do I connect two FreeBSD systems over a parallel line using PLIP? Please see the PLIP section of the Handbook. Why can I not create a /dev/ed0 device? Because they aren't necessary. In the Berkeley networking framework, network interfaces are only directly accessible by kernel code. Please see the /etc/rc.network file and the manual pages for the various network programs mentioned there for more information. If this leaves you totally confused, then you should pick up a book describing network administration on another BSD-related operating system; with few significant exceptions, administering networking on FreeBSD is basically the same as on SunOS 4.0 or Ultrix. How can I set up Ethernet aliases? If the alias is on the same subnet as an address already configured on the interface, then add netmask 0xffffffff to your &man.ifconfig.8; command-line, as in the following: &prompt.root; ifconfig ed0 alias 192.0.2.2 netmask 0xffffffff Otherwise, just specify the network address and netmask as usual: - &prompt.root; ifconfig ed0 alias 172.16.141.5 netmask 0xffffff00 + &prompt.root; ifconfig ed0 alias 172.16.141.5 netmask 0xffffff00 How do I get my 3C503 to use the other network port? If you want to use the other ports, you will have to specify an additional parameter on the &man.ifconfig.8; command line. The default port is link0. To use the AUI port instead of the BNC one, use link2. These flags should be specified using the ifconfig_* variables in /etc/rc.conf (see &man.rc.conf.5;). Why am I having trouble with NFS and FreeBSD? Certain PC network cards are better than others (to put it mildly) and can sometimes cause problems with network intensive applications like NFS. See the Handbook entry on NFS for more information on this topic. Why can I not NFS-mount from a Linux box? Some versions of the Linux NFS code only accept mount requests from a privileged port; try &prompt.root; mount -o -P linuxbox:/blah /mnt Why can I not NFS-mount from a Sun box? Sun workstations running SunOS 4.X only accept mount requests from a privileged port; try &prompt.root; mount -o -P sunbox:/blah /mnt Why does mountd keep telling me it can't change attributes and that I have a bad exports list on my FreeBSD NFS server? The most frequent problem is not understanding the correct format of /etc/exports. Please review &man.exports.5; and the NFS entry in the Handbook, especially the section on configuring NFS. Why am I having problems talking PPP to NeXTStep machines? Try disabling the TCP extensions in /etc/rc.conf (see &man.rc.conf.5;) by changing the following variable to NO: tcp_extensions=NO Xylogic's Annex boxes are also broken in this regard and you must use the above change to connect through them. How do I enable IP multicast support? FreeBSD supports multicast host operations by default. If you want your box to run as a multicast router, you need to recompile your kernel with the MROUTING option and run &man.mrouted.8;. FreeBSD will start &man.mrouted.8; at boot time if the flag mrouted_enable is set to "YES" in /etc/rc.conf. MBONE tools are available in their own ports category, mbone. If you are looking for the conference tools vic and vat, look there! Which network cards are based on the DEC PCI chipset? Here is a list compiled by Glen Foster gfoster@driver.nsta.org, with some more modern additions: Network cards based on the DEC PCI chipset Vendor Model ASUS PCI-L101-TB Accton ENI1203 Cogent EM960PCI Compex ENET32-PCI D-Link DE-530 Dayna DP1203, DP2100 DEC DE435, DE450 Danpex EN-9400P3 JCIS Condor JC1260 Linksys EtherPCI Mylex LNP101 SMC EtherPower 10/100 (Model 9332) SMC EtherPower (Model 8432) TopWare TE-3500P Znyx (2.2.x) ZX312, ZX314, ZX342, ZX345, ZX346, ZX348 Znyx (3.x) ZX345Q, ZX346Q, ZX348Q, ZX412Q, ZX414, ZX442, ZX444, ZX474, ZX478, ZX212, ZX214 (10mbps/hd)
Why do I have to use the FQDN for hosts on my site? You will probably find that the host is actually in a different domain; for example, if you are in foo.example.org and you wish to reach a host called mumble in the example.org domain, you will have to refer to it by the fully-qualified domain name, mumble.example.org, instead of just mumble. Traditionally, this was allowed by BSD BIND resolvers. However the current version of bind (see &man.named.8;) that ships with FreeBSD no longer provides default abbreviations for non-fully qualified domain names other than the domain you are in. So an unqualified host mumble must either be found as mumble.foo.example.org, or it will be searched for in the root domain. This is different from the previous behavior, where the search continued across mumble.example.org, and mumble.edu. Have a look at RFC 1535 for why this was considered bad practice, or even a security hole. As a good workaround, you can place the line search foo.example.org example.org instead of the previous domain foo.example.org into your /etc/resolv.conf file (see &man.resolv.conf.5;). However, make sure that the search order does not go beyond the boundary between local and public administration, as RFC 1535 calls it. Why do I get an error, Permission denied, for all networking operations? If you have compiled your kernel with the IPFIREWALL option, you need to be aware that the default policy is to deny all packets that are not explicitly allowed. If you had unintentionally misconfigured your system for firewalling, you can restore network operability by typing the following while logged in as root: &prompt.root; ipfw add 65534 allow all from any to any You can also set firewall_type="open" in /etc/rc.conf. For further information on configuring a FreeBSD firewall, see the Handbook section. How much overhead does IPFW incur? Please see the Handbook's Firewalls section, specifically the section on IPFW Overhead & Optimization. Why is my ipfw fwd rule to redirect a service to another machine not working? Possibly because you want to do network address translation (NAT) and not just forward packets. A fwd rule does exactly what it says; it forwards packets. It does not actually change the data inside the packet. Say we have a rule like: 01000 fwd 10.0.0.1 from any to foo 21 When a packet with a destination address of foo arrives at the machine with this rule, the packet is forwarded to 10.0.0.1, but it still has the destination address of foo! The destination address of the packet is not changed to 10.0.0.1. Most machines would probably drop a packet that they receive with a destination address that is not their own. Therefore, using a fwd rule does not often work the way the user expects. This behavior is a feature and not a bug. See the FAQ about redirecting services, the &man.natd.8; manual, or one of the several port redirecting utilities in the ports collection for a correct way to do this. How can I redirect service requests from one machine to another? You can redirect FTP (and other service) request with the socket package, available in the ports tree in category sysutils. Simply replace the service's command line to call socket instead, like so: ftp stream tcp nowait nobody /usr/local/bin/socket socket ftp.example.com ftp where ftp.example.com and ftp are the host and port to redirect to, respectively. Where can I get a bandwidth management tool? There are three bandwidth management tools available for FreeBSD. &man.dummynet.4; is integrated into FreeBSD (or more specifically, &man.ipfw.4;); ALTQ is available for free; Bandwidth Manager from Emerging Technologies is a commercial product. Why do I get /dev/bpf0: device not configured? You are running a program that requires the Berkeley Packet Filter (&man.bpf.4;), but it's not in your kernel. Add this to your kernel config file and build a new kernel: pseudo-device bpf # Berkeley Packet Filter On FreeBSD 4.X and earlier, you must also create the device node. After rebooting, go to the /dev directory and run: &prompt.root; sh MAKEDEV bpf0 Please see the Handbook entry on device nodes for more information on managing devices. How do I mount a disk from a Windows machine that is on my network, like smbmount in Linux? Use the SMBFS toolset. It includes a set of kernel modifications and a set of userland programs. The programs and information are available as net/smbfs in the ports collection, or in the base system as of 4.5-RELEASE and later. What are these messages about icmp-response bandwidth limit 300/200 pps in my log files? This is the kernel telling you that some activity is provoking it to send more ICMP or TCP reset (RST) responses than it thinks it should. ICMP responses are often generated as a result of attempted connections to unused UDP ports. TCP resets are generated as a result of attempted connections to unopened TCP ports. Among others, these are the kinds of activities which may cause these messages: Brute-force denial of service (DoS) attacks (as opposed to single-packet attacks which exploit a specific vulnerability). Port scans which attempt to connect to a large number of ports (as opposed to only trying a few well-known ports). The first number in the message tells you how many packets the kernel would have sent if the limit was not in place, and the second number tells you the limit. You can control the limit using the net.inet.icmp.icmplim sysctl variable like this, where 300 is the limit in packets per second: &prompt.root; sysctl -w net.inet.icmp.icmplim=300 If you do not want to see messages about this in your log files, but you still want the kernel to do response limiting, you can use the net.inet.icmp.icmplim_output sysctl variable to disable the output like this: &prompt.root; sysctl -w net.inet.icmp.icmplim_output=0 Finally, if you want to disable response limiting, you can set the net.inet.icmp.icmplim sysctl variable (see above for an example) to 0. Disabling response limiting is discouraged for the reasons listed above. What are these arp: unknown hardware address format error messages? This means that some device on your local Ethernet is using a MAC address in a format that FreeBSD does not recognize. This is probably caused by someone experimenting with an Ethernet card somewhere else on the network. You will see this most commonly on cable modem networks. It is harmless, and should not affect the performance of your FreeBSD machine. I've just installed CVSup but trying to execute it produces errors. What is wrong? First, see if the error message you are receiving is like the one shown below. /usr/libexec/ld-elf.so.1: Shared object "libXaw.so.6" not found Errors like these are caused by installing the net/cvsup port on a machine which does not have the XFree86 suite. If you want to use the GUI included with CVSup you will need to install XFree86 now. Alternatively if you just wish to use CVSup from a command line you should delete the package previously installed. Then install the net/cvsup-without-gui port. This is covered in more detail in the CVSup section of the Handbook. Security What is a sandbox? Sandbox is a security term. It can mean two things: A process which is placed inside a set of virtual walls that are designed to prevent someone who breaks into the process from being able to break into the wider system. The process is said to be able to play inside the walls. That is, nothing the process does in regards to executing code is supposed to be able to breech the walls so you do not have to do a detailed audit of its code to be able to say certain things about its security. The walls might be a userid, for example. This is the definition used in the security and named man pages. Take the ntalk service, for example (see /etc/inetd.conf). This service used to run as userid root. Now it runs as userid tty. The tty user is a sandbox designed to make it more difficult for someone who has successfully hacked into the system via ntalk from being able to hack beyond that user id. A process which is placed inside a simulation of the machine. This is more hard-core. Basically it means that someone who is able to break into the process may believe that he can break into the wider machine but is, in fact, only breaking into a simulation of that machine and not modifying any real data. The most common way to accomplish this is to build a simulated environment in a subdirectory and then run the processes in that directory chroot'd (i.e. / for that process is this directory, not the real / of the system). Another common use is to mount an underlying filesystem read-only and then create a filesystem layer on top of it that gives a process a seemingly writeable view into that filesystem. The process may believe it is able to write to those files, but only the process sees the effects - other processes in the system do not, necessarily. An attempt is made to make this sort of sandbox so transparent that the user (or hacker) does not realize that he is sitting in it. Unix implements two core sandboxes. One is at the process level, and one is at the userid level. Every Unix process is completely firewalled off from every other Unix process. One process cannot modify the address space of another. This is unlike Windows where a process can easily overwrite the address space of any other, leading to a crash. A Unix process is owned by a particular userid. If the userid is not the root user, it serves to firewall the process off from processes owned by other users. The userid is also used to firewall off on-disk data. What is securelevel? The securelevel is a security mechanism implemented in the kernel. Basically, when the securelevel is positive, the kernel restricts certain tasks; not even the superuser (i.e., root) is allowed to do them. At the time of this writing, the securelevel mechanism is capable of, among other things, limiting the ability to, unset certain file flags, such as schg (the system immutable flag), write to kernel memory via /dev/mem and /dev/kmem, load kernel modules, and alter &man.ipfirewall.4; rules. To check the status of the securelevel on a running system, simply execute the following command: &prompt.root; sysctl kern.securelevel The output will contain the name of the &man.sysctl.8; variable (in this case, kern.securelevel) and a number. The latter is the current value of the securelevel. If it is positive (i.e., greater than 0), at least some of the securelevel's protections are enabled. You cannot lower the securelevel of a running system; being able to do that would defeat its purpose. If you need to do a task that requires that the securelevel be non-positive (e.g., an installworld or changing the date), you will have to change the securelevel setting in /etc/rc.conf (you want to look for the kern_securelevel and kern_securelevel_enable variables) and reboot. For more information on securelevel and the specific things all the levels do, please consult the &man.init.8; manual page. Securelevel is not a silver bullet; it has many known deficiencies. More often than not, it provides a false sense of security. One of its biggest problems is that in order for it to be at all effective, all files used in the boot process up until the securelevel is set must be protected. If an attacker can get the system to execute their code prior to the securelevel being set (which happens quite late in the boot process since some things the system must do at start-up cannot be done at an elevated securelevel), its protections are invalidated. While this task of protecting all files used in the boot process is not technically impossible, if it is achieved, system maintenance will become a nightmare since one would have to take the system down, at least to single-user mode, to modify a configuration file. This point and others are often discussed on the mailing lists, particularly the &a.security;. Please search the archives here for an extensive discussion. Some people are hopeful that securelevel will soon go away in favor of a more fine-grained mechanism, but things are still hazy in this respect. Consider yourself warned. BIND (named) is listening on port 53 and some other high-numbered port. What is going on? FreeBSD 3.0 and later use a version of BIND that uses a random high-numbered port for outgoing queries. If you want to use port 53 for outgoing queries, either to get past a firewall or to make yourself feel better, you can try the following in /etc/namedb/named.conf: options { query-source address * port 53; }; You can replace the * with a single IP address if you want to tighten things further. Congratulations, by the way. It is good practice to read your &man.sockstat.1; output and notice odd things! Sendmail is listening on port 587 as well as the standard port 25! What is going on? Recent versions of Sendmail support a mail submission feature that runs over port 587. This is not yet widely supported, but is growing in popularity. What is this UID 0 toor account? Have I been compromised? Do not worry. toor is an alternative superuser account (toor is root spelt backwards). Previously it was created when the &man.bash.1; shell was installed but now it is created by default. It is intended to be used with a non-standard shell so you do not have to change root's default shell. This is important as shells which are not part of the base distribution (for example a shell installed from ports or packages) are likely be to be installed in /usr/local/bin which, by default, resides on a different filesystem. If root's shell is located in /usr/local/bin and /usr (or whatever filesystem contains /usr/local/bin) is not mounted for some reason, root will not be able to log in to fix a problem (although if you reboot into single user mode you will be prompted for the path to a shell). Some people use toor for day-to-day root tasks with a non-standard shell, leaving root, with a standard shell, for single user mode or emergencies. By default you cannot log in using toor as it does not have a password, so log in as root and set a password for toor if you want to use it. Why is suidperl not working properly? For security reasons, suidperl is installed without the suid bit by default. The system administrator can enable suid behavior with the following command. &prompt.root; chmod u+s /usr/bin/suidperl If you want suidperl to be built suid during upgrades from source, edit /etc/make.conf and add ENABLE_SUIDPERL=true before you run make buildworld. PPP I cannot make &man.ppp.8; work. What am I doing wrong? You should first read the &man.ppp.8; manual page and the PPP section of the handbook. Enable logging with the command set log Phase Chat Connect Carrier lcp ipcp ccp command This command may be typed at the &man.ppp.8; command prompt or it may be entered in the /etc/ppp/ppp.conf configuration file (the start of the default section is the best place to put it). Make sure that /etc/syslog.conf (see &man.syslog.conf.5;) contains the lines !ppp *.* /var/log/ppp.log and that the file /var/log/ppp.log exists. You can now find out a lot about what is going on from the log file. Do not worry if it does not all make sense. If you need to get help from someone, it may make sense to them. If your version of &man.ppp.8; does not understand the set log command, you should download the latest version. It will build on FreeBSD version 2.1.5 and higher. Why does &man.ppp.8; hang when I run it? This is usually because your hostname will not resolve. The best way to fix this is to make sure that /etc/hosts is consulted by your resolver first by editing /etc/host.conf and putting the hosts line first. Then, simply put an entry in /etc/hosts for your local machine. If you have no local network, change your localhost line: 127.0.0.1 foo.example.com foo localhost Otherwise, simply add another entry for your host. Consult the relevant manual pages for more details. You should be able to successfully ping -c1 `hostname` when you are done. Why will &man.ppp.8; not dial in -auto mode? First, check that you have got a default route. By running netstat -rn (see &man.netstat.1;), you should see two entries like this: Destination Gateway Flags Refs Use Netif Expire default 10.0.0.2 UGSc 0 0 tun0 10.0.0.2 10.0.0.1 UH 0 0 tun0 This is assuming that you have used the addresses from the handbook, the manual page or from the ppp.conf.sample file. If you do not have a default route, it may be because you are running an old version of &man.ppp.8; that does not understand the word HISADDR in the ppp.conf file. If your version of &man.ppp.8; is from before FreeBSD 2.2.5, change the add 0 0 HISADDR line to one saying add 0 0 10.0.0.2 Another reason for the default route line being missing is that you have mistakenly set up a default router in your /etc/rc.conf (see &man.rc.conf.5;) file (this file was called /etc/sysconfig prior to release 2.2.2), and you have omitted the line saying delete ALL from ppp.conf. If this is the case, go back to the Final system configuration section of the handbook. What does No route to host mean? This error is usually due to a missing MYADDR: delete ALL add 0 0 HISADDR section in your /etc/ppp/ppp.linkup file. This is only necessary if you have a dynamic IP address or do not know the address of your gateway. If you are using interactive mode, you can type the following after entering packet mode (packet mode is indicated by the capitalized PPP in the prompt): delete ALL add 0 0 HISADDR Refer to the PPP and Dynamic IP addresses section of the handbook for further details. Why does my connection drop after about 3 minutes? The default PPP timeout is 3 minutes. This can be adjusted with the line set timeout NNN where NNN is the number of seconds of inactivity before the connection is closed. If NNN is zero, the connection is never closed due to a timeout. It is possible to put this command in the ppp.conf file, or to type it at the prompt in interactive mode. It is also possible to adjust it on the fly while the line is active by connecting to ppp's server socket using &man.telnet.1; or &man.pppctl.8;. Refer to the &man.ppp.8; man page for further details. Why does my connection drop under heavy load? If you have Link Quality Reporting (LQR) configured, it is possible that too many LQR packets are lost between your machine and the peer. Ppp deduces that the line must therefore be bad, and disconnects. Prior to FreeBSD version 2.2.5, LQR was enabled by default. It is now disabled by default. LQR can be disabled with the line disable lqr Why does my connection drop after a random amount of time? Sometimes, on a noisy phone line or even on a line with call waiting enabled, your modem may hang up because it thinks (incorrectly) that it lost carrier. There is a setting on most modems for determining how tolerant it should be to temporary losses of carrier. On a USR Sportster for example, this is measured by the S10 register in tenths of a second. To make your modem more forgiving, you could add the following send-expect sequence to your dial string: set dial "...... ATS10=10 OK ......" Refer to your modem manual for details. Why does my connection hang after a random amount of time? Many people experience hung connections with no apparent explanation. The first thing to establish is which side of the link is hung. If you are using an external modem, you can simply try using &man.ping.8; to see if the TD light is flashing when you transmit data. If it flashes (and the RD light does not), the problem is with the remote end. If TD does not flash, the problem is local. With an internal modem, you will need to use the set server command in your ppp.conf file. When the hang occurs, connect to &man.ppp.8; using &man.pppctl.8;. If your network connection suddenly revives (PPP was revived due to the activity on the diagnostic socket) or if you cannot connect (assuming the set socket command succeeded at startup time), the problem is local. If you can connect and things are still hung, enable local async logging with set log local async and use &man.ping.8; from another window or terminal to make use of the link. The async logging will show you the data being transmitted and received on the link. If data is going out and not coming back, the problem is remote. Having established whether the problem is local or remote, you now have two possibilities: If the problem is remote, read on entry . If the problem is local, read on entry . The remote end is not responding. What can I do? There is very little you can do about this. Most ISPs will refuse to help if you are not running a Microsoft OS. You can enable lqr in your ppp.conf file, allowing &man.ppp.8; to detect the remote failure and hang up, but this detection is relatively slow and therefore not that useful. You may want to avoid telling your ISP that you are running user-PPP... First, try disabling all local compression by adding the following to your configuration: disable pred1 deflate deflate24 protocomp acfcomp shortseq vj deny pred1 deflate deflate24 protocomp acfcomp shortseq vj Then reconnect to ensure that this makes no difference. If things improve or if the problem is solved completely, determine which setting makes the difference through trial and error. This will provide good ammunition when you contact your ISP (although it may make it apparent that you are not running a Microsoft product). Before contacting your ISP, enable async logging locally and wait until the connection hangs again. This may use up quite a bit of disk space. The last data read from the port may be of interest. It is usually ascii data, and may even describe the problem (Memory fault, core dumped?). If your ISP is helpful, they should be able to enable logging on their end, then when the next link drop occurs, they may be able to tell you why their side is having a problem. Feel free to send the details to &a.brian;, or even to ask your ISP to contact me directly. &man.ppp.8; has hung. What can I do? Your best bet here is to rebuild &man.ppp.8; by adding CFLAGS+=-g and STRIP= to the end of the Makefile, then doing a make clean && make && make install. When &man.ppp.8; hangs, find the &man.ppp.8; process id with ps ajxww | fgrep ppp and run gdb ppp PID. From the gdb prompt, you can then use bt to get a stack trace. Send the results to &a.brian;. Why does nothing happen after the Login OK! message? Prior to FreeBSD version 2.2.5, once the link was established, &man.ppp.8; would wait for the peer to initiate the Line Control Protocol (LCP). Many ISPs will not initiate negotiations and expect the client to do so. To force &man.ppp.8; to initiate the LCP, use the following line: set openmode active It usually does no harm if both sides initiate negotiation, so openmode is now active by default. However, the next section explains when it does do some harm. I keep seeing errors about magic being the same. What does it mean? Occasionally, just after connecting, you may see messages in the log that say magic is the same. Sometimes, these messages are harmless, and sometimes one side or the other exits. Most PPP implementations cannot survive this problem, and even if the link seems to come up, you will see repeated configure requests and configure acknowledgments in the log file until &man.ppp.8; eventually gives up and closes the connection. This normally happens on server machines with slow disks that are spawning a getty on the port, and executing &man.ppp.8; from a login script or program after login. I have also heard reports of it happening consistently when using slirp. The reason is that in the time taken between &man.getty.8; exiting and &man.ppp.8; starting, the client-side &man.ppp.8; starts sending Line Control Protocol (LCP) packets. Because ECHO is still switched on for the port on the server, the client &man.ppp.8; sees these packets reflect back. One part of the LCP negotiation is to establish a magic number for each side of the link so that reflections can be detected. The protocol says that when the peer tries to negotiate the same magic number, a NAK should be sent and a new magic number should be chosen. During the period that the server port has ECHO turned on, the client &man.ppp.8; sends LCP packets, sees the same magic in the reflected packet and NAKs it. It also sees the NAK reflect (which also means &man.ppp.8; must change its magic). This produces a potentially enormous number of magic number changes, all of which are happily piling into the server's tty buffer. As soon as &man.ppp.8; starts on the server, it is flooded with magic number changes and almost immediately decides it has tried enough to negotiate LCP and gives up. Meanwhile, the client, who no longer sees the reflections, becomes happy just in time to see a hangup from the server. This can be avoided by allowing the peer to start negotiating with the following line in your ppp.conf file: set openmode passive This tells &man.ppp.8; to wait for the server to initiate LCP negotiations. Some servers however may never initiate negotiations. If this is the case, you can do something like: set openmode active 3 This tells &man.ppp.8; to be passive for 3 seconds, and then to start sending LCP requests. If the peer starts sending requests during this period, &man.ppp.8; will immediately respond rather than waiting for the full 3 second period. LCP negotiations continue until the connection is closed. What is wrong? There is currently an implementation mis-feature in &man.ppp.8; where it does not associate LCP, CCP & IPCP responses with their original requests. As a result, if one PPP implementation is more than 6 seconds slower than the other side, the other side will send two additional LCP configuration requests. This is fatal. Consider two implementations, A and B. A starts sending LCP requests immediately after connecting and B takes 7 seconds to start. When B starts, A has sent 3 LCP REQs. We are assuming the line has ECHO switched off, otherwise we would see magic number problems as described in the previous section. B sends a REQ, then an ACK to the first of A's REQs. This results in A entering the OPENED state and sending and ACK (the first) back to B. In the meantime, B sends back two more ACKs in response to the two additional REQs sent by A before B started up. B then receives the first ACK from A and enters the OPENED state. A receives the second ACK from B and goes back to the REQ-SENT state, sending another (forth) REQ as per the RFC. It then receives the third ACK and enters the OPENED state. In the meantime, B receives the forth REQ from A, resulting in it reverting to the ACK-SENT state and sending another (second) REQ and (forth) ACK as per the RFC. A gets the REQ, goes into REQ-SENT and sends another REQ. It immediately receives the following ACK and enters OPENED. This goes on until one side figures out that they are getting nowhere and gives up. The best way to avoid this is to configure one side to be passive - that is, make one side wait for the other to start negotiating. This can be done with the set openmode passive command. Care should be taken with this option. You should also use the set stopped N command to limit the amount of time that &man.ppp.8; waits for the peer to begin negotiations. Alternatively, the set openmode active N command (where N is the number of seconds to wait before starting negotiations) can be used. Check the manual page for details. Why does &man.ppp.8; lock up shortly after connection? Prior to version 2.2.5 of FreeBSD, it was possible that your link was disabled shortly after connection due to &man.ppp.8; mis-handling Predictor1 compression negotiation. This would only happen if both sides tried to negotiate different Compression Control Protocols (CCP). This problem is now corrected, but if you are still running an old version of &man.ppp.8; the problem can be circumvented with the line disable pred1 Why does &man.ppp.8; lock up when I shell out to test it? When you execute the shell or ! command, &man.ppp.8; executes a shell (or if you have passed any arguments, &man.ppp.8; will execute those arguments). Ppp will wait for the command to complete before continuing. If you attempt to use the PPP link while running the command, the link will appear to have frozen. This is because &man.ppp.8; is waiting for the command to complete. If you wish to execute commands like this, use the !bg command instead. This will execute the given command in the background, and &man.ppp.8; can continue to service the link. Why does &man.ppp.8; over a null-modem cable never exit? There is no way for &man.ppp.8; to automatically determine that a direct connection has been dropped. This is due to the lines that are used in a null-modem serial cable. When using this sort of connection, LQR should always be enabled with the line enable lqr LQR is accepted by default if negotiated by the peer. Why does &man.ppp.8; dial for no reason in -auto mode? If &man.ppp.8; is dialing unexpectedly, you must determine the cause, and set up Dial filters (dfilters) to prevent such dialing. To determine the cause, use the following line: set log +tcp/ip This will log all traffic through the connection. The next time the line comes up unexpectedly, you will see the reason logged with a convenient timestamp next to it. You can now disable dialing under these circumstances. Usually, this sort of problem arises due to DNS lookups. To prevent DNS lookups from establishing a connection (this will not prevent &man.ppp.8; from passing the packets through an established connection), use the following: set dfilter 1 deny udp src eq 53 set dfilter 2 deny udp dst eq 53 set dfilter 3 permit 0/0 0/0 This is not always suitable, as it will effectively break your demand-dial capabilities - most programs will need a DNS lookup before doing any other network related things. In the DNS case, you should try to determine what is actually trying to resolve a host name. A lot of the time, &man.sendmail.8; is the culprit. You should make sure that you tell sendmail not to do any DNS lookups in its configuration file. See the section on using email with a dialup connection in the FreeBSD Handbook for details on how to create your own configuration file and what should go into it. You may also want to add the following line to your .mc file: define(`confDELIVERY_MODE', `d')dnl This will make sendmail queue everything until the queue is run (usually, sendmail is invoked with , telling it to run the queue every 30 minutes) or until a sendmail -q is done (perhaps from your ppp.linkup file). What do these CCP errors mean? I keep seeing the following errors in my log file: CCP: CcpSendConfigReq CCP: Received Terminate Ack (1) state = Req-Sent (6) This is because &man.ppp.8; is trying to negotiate Predictor1 compression, and the peer does not want to negotiate any compression at all. The messages are harmless, but if you wish to remove them, you can disable Predictor1 compression locally too: disable pred1 Why does &man.ppp.8; not log my connection speed? In order to log all lines of your modem conversation, you must enable the following: set log +connect This will make &man.ppp.8; log everything up until the last requested expect string. If you wish to see your connect speed and are using PAP or CHAP (and therefore do not have anything to chat after the CONNECT in the dial script - no set login script), you must make sure that you instruct &man.ppp.8; to expect the whole CONNECT line, something like this: set dial "ABORT BUSY ABORT NO\\sCARRIER TIMEOUT 4 \ \"\" ATZ OK-ATZ-OK ATDT\\T TIMEOUT 60 CONNECT \\c \\n" Here, we get our CONNECT, send nothing, then expect a line-feed, forcing &man.ppp.8; to read the whole CONNECT response. Why does &man.ppp.8; ignore the \ character in my chat script? Ppp parses each line in your config files so that it can interpret strings such as set phone "123 456 789" correctly and realize that the number is actually only one argument. In order to specify a " character, you must escape it using a backslash (\). When the chat interpreter parses each argument, it re-interprets the argument in order to find any special escape sequences such as \P or \T (see the manual page). As a result of this double-parsing, you must remember to use the correct number of escapes. If you wish to actually send a \ character to (say) your modem, you would need something like: set dial "\"\" ATZ OK-ATZ-OK AT\\\\X OK" resulting in the following sequence: ATZ OK AT\X OK or set phone 1234567 set dial "\"\" ATZ OK ATDT\\T" resulting in the following sequence: ATZ OK ATDT1234567 Why does &man.ppp.8; get a seg-fault, but I see no ppp.core file? Ppp (or any other program for that matter) should never dump core. Because &man.ppp.8; runs with an effective user id of 0, the operating system will not write &man.ppp.8;'s core image to disk before terminating it. If, however &man.ppp.8; is actually terminating due to a segmentation violation or some other signal that normally causes core to be dumped, and you are sure you are using the latest version (see the start of this section), then you should do the following: &prompt.user; tar xfz ppp-*.src.tar.gz &prompt.user; cd ppp*/ppp &prompt.user; echo STRIP= >>Makefile &prompt.user; echo CFLAGS+=-g >>Makefile &prompt.user; make clean all &prompt.user; su &prompt.root; make install &prompt.root; chmod 555 /usr/sbin/ppp You will now have a debuggable version of &man.ppp.8; installed. You will have to be root to run &man.ppp.8; as all of its privileges have been revoked. When you start &man.ppp.8;, take a careful note of what your current directory was at the time. Now, if and when &man.ppp.8; receives the segmentation violation, it will dump a core file called ppp.core. You should then do the following: &prompt.user; su &prompt.root; gdb /usr/sbin/ppp ppp.core (gdb) bt ..... (gdb) f 0 .... (gdb) i args .... (gdb) l ..... All of this information should be given alongside your question, making it possible to diagnose the problem. If you are familiar with gdb, you may wish to find out some other bits and pieces such as what actually caused the dump and the addresses & values of the relevant variables. Why does the process that forces a dial in auto mode never connect? This was a known problem with &man.ppp.8; set up to negotiate a dynamic local IP number with the peer in auto mode. It is fixed in the latest version - search the manual page for iface. The problem was that when that initial program calls &man.connect.2;, the IP number of the tun interface is assigned to the socket endpoint. The kernel creates the first outgoing packet and writes it to the tun device. &man.ppp.8; then reads the packet and establishes a connection. If, as a result of &man.ppp.8;'s dynamic IP assignment, the interface address is changed, the original socket endpoint will be invalid. Any subsequent packets sent to the peer will usually be dropped. Even if they are not, any responses will not route back to the originating machine as the IP number is no longer owned by that machine. There are several theoretical ways to approach this problem. It would be nicest if the peer would re-assign the same IP number if possible :-) The current version of &man.ppp.8; does this, but most other implementations do not. The easiest method from our side would be to never change the tun interface IP number, but instead to change all outgoing packets so that the source IP number is changed from the interface IP to the negotiated IP on the fly. This is essentially what the iface-alias option in the latest version of &man.ppp.8; is doing (with the help of &man.libalias.3; and &man.ppp.8;'s switch) - it is maintaining all previous interface addresses and NATing them to the last negotiated address. Another alternative (and probably the most reliable) would be to implement a system call that changes all bound sockets from one IP to another. &man.ppp.8; would use this call to modify the sockets of all existing programs when a new IP number is negotiated. The same system call could be used by dhcp clients when they are forced to re-bind() their sockets. Yet another possibility is to allow an interface to be brought up without an IP number. Outgoing packets would be given an IP number of 255.255.255.255 up until the first SIOCAIFADDR ioctl is done. This would result in fully binding the socket. It would be up to &man.ppp.8; to change the source IP number, but only if it is set to 255.255.255.255, and only the IP number and IP checksum would need to change. This, however is a bit of a hack as the kernel would be sending bad packets to an improperly configured interface, on the assumption that some other mechanism is capable of fixing things retrospectively. Why do most games not work with the -nat switch? The reason games and the like do not work when libalias is in use is that the machine on the outside will try to open a connection or send (unsolicited) UDP packets to the machine on the inside. The NAT software does not know that it should send these packets to the interior machine. To make things work, make sure that the only thing running is the software that you are having problems with, then either run tcpdump on the tun interface of the gateway or enable &man.ppp.8; tcp/ip logging (set log +tcp/ip) on the gateway. When you start the offending software, you should see packets passing through the gateway machine. When something comes back from the outside, it will be dropped (that is the problem). Note the port number of these packets then shut down the offending software. Do this a few times to see if the port numbers are consistent. If they are, then the following line in the relevant section of /etc/ppp/ppp.conf will make the software functional: nat port proto internalmachine:port port where proto is either tcp or udp, internalmachine is the machine that you want the packets to be sent to and port is the destination port number of the packets. You will not be able to use the software on other machines without changing the above command, and running the software on two internal machines at the same time is out of the question - after all, the outside world is seeing your entire internal network as being just a single machine. If the port numbers are not consistent, there are three more options: Submit support in libalias. Examples of special cases can be found in /usr/src/lib/libalias/alias_*.c (alias_ftp.c is a good prototype). This usually involves reading certain recognised outgoing packets, identifying the instruction that tells the outside machine to initiate a connection back to the internal machine on a specific (random) port and setting up a route in the alias table so that the subsequent packets know where to go. This is the most difficult solution, but it is the best and will make the software work with multiple machines. Use a proxy. The application may support socks5 for example, or (as in the cvsup case) may have a passive option that avoids ever requesting that the peer open connections back to the local machine. Redirect everything to the internal machine using nat addr. This is the sledge-hammer approach. Has anybody made a list of useful port numbers? Not yet, but this is intended to grow into such a list (if any interest is shown). In each example, internal should be replaced with the IP number of the machine playing the game. Asheron's Call nat port udp internal :65000 65000 Manually change the port number within the game to 65000. If you have got a number of machines that you wish to play on assign a unique port number for each (i.e. 65001, 65002, etc) and add a nat port line for each one. Half Life nat port udp internal:27005 27015 PCAnywhere 8.0 nat port udp internal:5632 5632 nat port tcp internal:5631 5631 Quake nat port udp internal:6112 6112 Alternatively, you may want to take a look at www.battle.net for Quake proxy support. Quake 2 nat port udp internal:27901 27910 nat port udp internal:60021 60021 nat port udp internal:60040 60040 Red Alert nat port udp internal:8675 8675 nat port udp internal:5009 5009 What are FCS errors? FCS stands for Frame Check Sequence. Each PPP packet has a checksum attached to ensure that the data being received is the data being sent. If the FCS of an incoming packet is incorrect, the packet is dropped and the HDLC FCS count is increased. The HDLC error values can be displayed using the show hdlc command. If your link is bad (or if your serial driver is dropping packets), you will see the occasional FCS error. This is not usually worth worrying about although it does slow down the compression protocols substantially. If you have an external modem, make sure your cable is properly shielded from interference - this may eradicate the problem. If your link freezes as soon as you have connected and you see a large number of FCS errors, this may be because your link is not 8 bit clean. Make sure your modem is not using software flow control (XON/XOFF). If your datalink must use software flow control, use the command set accmap 0x000a0000 to tell &man.ppp.8; to escape the ^Q and ^S characters. Another reason for seeing too many FCS errors may be that the remote end has stopped talking PPP. You may want to enable async logging at this point to determine if the incoming data is actually a login or shell prompt. If you have a shell prompt at the remote end, it is possible to terminate &man.ppp.8; without dropping the line by using the close lcp command (a following term command will reconnect you to the shell on the remote machine. If nothing in your log file indicates why the link might have been terminated, you should ask the remote administrator (your ISP?) why the session was terminated. Why do MacOS and Windows 98 connections freeze when running PPPoE on the gateway? Thanks to Michael Wozniak mwozniak@netcom.ca for figuring this out and Dan Flemming danflemming@mac.com for the Mac solution: This is due to what is called a Black Hole router. MacOS and Windows 98 (and maybe other Microsoft OSs) send TCP packets with a requested segment size too big to fit into a PPPoE frame (MTU is 1500 by default for Ethernet) and have the do not fragment bit set (default of TCP) and the Telco router is not sending ICMP must fragment back to the www site you are trying to load. (Alternatively, the router is sending the ICMP packet correctly, but the firewall at the www site is dropping it.) When the www server is sending you frames that do not fit into the PPPoE pipe the Telco router drops them on the floor and your page does not load (some pages/graphics do as they are smaller than a MSS.) This seems to be the default of most Telco PPPoE configurations (if only they knew how to program a router... sigh...) One fix is to use regedit on your 95/98 boxes to add the following registry entry... HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Class\NetTrans\0000\MaxMTU It should be a string with a value 1436, as some ADSL routers are reported to be unable to deal with packets larger than this. This registry key has been changed to Tcpip\Parameters\Interfaces\ID for adapter\MTU in Windows 2000 and becomes a DWORD. Refer to the Microsoft Knowledge Base documents Q158474 - Windows TCPIP Registry Entries and Q120642 - TCPIP & NBT Configuration Parameters for Windows NT for more information on changing Windows MTU to work with a NAT router. Another regedit possibility under Windows 2000 is to set the Tcpip\Parameters\Interfaces\ID for adapter\EnablePMTUBHDetect DWORD to 1 as mentioned in the Microsoft document 120642 mentioned above. Unfortunately, MacOS does not provide an interface for changing TCP/IP settings. However, there is commercial software available, such as OTAdvancedTuner (OT for OpenTransport, the MacOS TCP/IP stack) by Sustainable Softworks, that will allow users to customize TCP/IP settings. MacOS NAT users should select ip_interface_MTU from the drop-down menu, enter 1450 instead of 1500 in the box, click the box next to Save as Auto Configure, and click Make Active. The latest version of &man.ppp.8; (2.3 or greater) has an enable tcpmssfixup command that will automatically adjust the MSS to an appropriate value. This facility is enabled by default. If you are stuck with an older version of &man.ppp.8;, you may want to look at the tcpmssd port. None of this helps - I am desperate! What can I do? If all else fails, send as much information as you can, including your config files, how you are starting &man.ppp.8;, the relevant parts of your log file and the output of the netstat -rn command (before and after connecting) to the &a.questions; or the comp.unix.bsd.freebsd.misc news group, and someone should point you in the right direction. Serial Communications This section answers common questions about serial communications with FreeBSD. PPP and SLIP are covered in the Networking section. How do I tell if FreeBSD found my serial ports? As the FreeBSD kernel boots, it will probe for the serial ports in your system for which the kernel was configured. You can either watch your system closely for the messages it prints or run the command &prompt.user; dmesg | grep sio after your system is up and running. Here is some example output from the above command: sio0 at 0x3f8-0x3ff irq 4 on isa sio0: type 16550A sio1 at 0x2f8-0x2ff irq 3 on isa sio1: type 16550A This shows two serial ports. The first is on irq 4, is using port address 0x3f8, and has a 16550A-type UART chip. The second uses the same kind of chip but is on irq 3 and is at port address 0x2f8. Internal modem cards are treated just like serial ports---except that they always have a modem attached to the port. The GENERIC kernel includes support for two serial ports using the same irq and port address settings in the above example. If these settings are not right for your system, or if you have added modem cards or have more serial ports than your kernel is configured for, just reconfigure your kernel. See section about building a kernel for more details. How do I tell if FreeBSD found my modem cards? Refer to the answer to the previous question. How do I access the serial ports on FreeBSD? The third serial port, sio2 (see &man.sio.4;, known as COM3 in DOS), is on /dev/cuaa2 for dial-out devices, and on /dev/ttyd2 for dial-in devices. What is the difference between these two classes of devices? You use ttydX for dial-ins. When opening /dev/ttydX in blocking mode, a process will wait for the corresponding cuaaX device to become inactive, and then wait for the carrier detect line to go active. When you open the cuaaX device, it makes sure the serial port is not already in use by the ttydX device. If the port is available, it steals it from the ttydX device. Also, the cuaaX device does not care about carrier detect. With this scheme and an auto-answer modem, you can have remote users log in and you can still dial out with the same modem and the system will take care of all the conflicts. How do I enable support for a multiport serial card? Again, the section on kernel configuration provides information about configuring your kernel. For a multiport serial card, place an &man.sio.4; line for each serial port on the card in the kernel configuration file. But place the irq and vector specifiers on only one of the entries. All of the ports on the card should share one irq. For consistency, use the last serial port to specify the irq. Also, specify the COM_MULTIPORT option. The following example is for an AST 4-port serial card on irq 7: options "COM_MULTIPORT" device sio4 at isa? port 0x2a0 tty flags 0x781 device sio5 at isa? port 0x2a8 tty flags 0x781 device sio6 at isa? port 0x2b0 tty flags 0x781 device sio7 at isa? port 0x2b8 tty flags 0x781 irq 7 vector siointr The flags indicate that the master port has minor number 7 (0x700), diagnostics enabled during probe (0x080), and all the ports share an irq (0x001). Can FreeBSD handle multiport serial cards sharing irqs? Not yet. You will have to use a different irq for each card. Can I set the default serial parameters for a port? The ttydX (or cuaaX) device is the regular device you will want to open for your applications. When a process opens the device, it will have a default set of terminal I/O settings. You can see these settings with the command &prompt.root; stty -a -f /dev/ttyd1 When you change the settings to this device, the settings are in effect until the device is closed. When it is reopened, it goes back to the default set. To make changes to the default set, you can open and adjust the settings of the initial state device. For example, to turn on CLOCAL mode, 8 bits, and XON/XOFF flow control by default for ttyd5, do: &prompt.root; stty -f /dev/ttyid5 clocal cs8 ixon ixoff A good place to do this is in /etc/rc.serial. Now, an application will have these settings by default when it opens ttyd5. It can still change these settings to its liking, though. You can also prevent certain settings from being changed by an application by making adjustments to the lock state device. For example, to lock the speed of ttyd5 to 57600 bps, do &prompt.root; stty -f /dev/ttyld5 57600 Now, an application that opens ttyd5 and tries to change the speed of the port will be stuck with 57600 bps. Naturally, you should make the initial state and lock state devices writable only by root. The &man.MAKEDEV.8; script does NOT do this when it creates the device entries. How can I enable dialup logins on my modem? So you want to become an Internet service provider, eh? First, you will need one or more modems that can auto-answer. Your modem will need to assert carrier-detect when it detects a carrier and not assert it all the time. It will need to hang up the phone and reset itself when the data terminal ready (DTR) line goes from on to off. It should probably use RTS/CTS flow control or no local flow control at all. Finally, it must use a constant speed between the computer and itself, but (to be nice to your callers) it should negotiate a speed between itself and the remote modem. For many Hayes command-set--compatible modems, this command will make these settings and store them in nonvolatile memory: AT &C1 &D3 &K3 &Q6 S0=1 &W See the section on sending AT commands below for information on how to make these settings without resorting to an MS-DOS terminal program. Next, make an entry in /etc/ttys (see &man.ttys.5;) for the modem. This file lists all the ports on which the operating system will await logins. Add a line that looks something like this: ttyd1 "/usr/libexec/getty std.57600" dialup on insecure This line indicates that the second serial port (/dev/ttyd1) has a modem connected running at 57600 bps and no parity (std.57600, which comes from the file /etc/gettytab, see &man.gettytab.5;). The terminal type for this port is dialup. The port is on and is insecure---meaning root logins on the port are not allowed. For dialin ports like this one, use the ttydX entry. It is common practice to use dialup as the terminal type. Many users set up in their .profile or .login files a prompt for the actual terminal type if the starting type is dialup. The example shows the port as insecure. To become root on this port, you have to login as a regular user, then &man.su.1; to become root. If you use secure then root can login in directly. After making modifications to /etc/ttys, you need to send a hangup or HUP signal to the &man.init.8; process: &prompt.root; kill -HUP 1 This forces the &man.init.8; process to reread /etc/ttys. The init process will then start getty processes on all on ports. You can find out if logins are available for your port by typing &prompt.user; ps -ax | grep '[t]tyd1' You should see something like: 747 ?? I 0:00.04 /usr/libexec/getty std.57600 ttyd1 How can I connect a dumb terminal to my FreeBSD box? If you are using another computer as a terminal into your FreeBSD system, get a null modem cable to go between the two serial ports. If you are using an actual terminal, see its accompanying instructions. Then, modify /etc/ttys (see &man.ttys.5;), like above. For example, if you are hooking up a WYSE-50 terminal to the fifth serial port, use an entry like this: ttyd4 "/usr/libexec/getty std.38400" wyse50 on secure This example shows that the port on /dev/ttyd4 has a wyse50 terminal connected at 38400 bps with no parity (std.38400 from /etc/gettytab, see &man.gettytab.5;) and root logins are allowed (secure). Why can I not run tip or cu? On your system, the programs &man.tip.1; and &man.cu.1; are probably executable only by uucp and group dialer. You can use the group dialer to control who has access to your modem or remote systems. Just add yourself to group dialer. Alternatively, you can let everyone on your system run &man.tip.1; and &man.cu.1; by typing: &prompt.root; chmod 4511 /usr/bin/cu &prompt.root; chmod 4511 /usr/bin/tip My stock Hayes modem is not supported---what can I do? Actually, the manual page for &man.tip.1; is out of date. There is a generic Hayes dialer already built in. Just use at=hayes in your /etc/remote (see &man.remote.5;) file. The Hayes driver is not smart enough to recognize some of the advanced features of newer modems---messages like BUSY, NO DIALTONE, or CONNECT 115200 will just confuse it. You should turn those messages off when you use &man.tip.1; (using ATX0&W). Also, the dial timeout for &man.tip.1; is 60 seconds. Your modem should use something less, or else tip will think there is a communication problem. Try ATS7=45&W. Actually, as shipped &man.tip.1; does not yet support it fully. The solution is to edit the file tipconf.h in the directory /usr/src/usr.bin/tip/tip. Obviously you need the source distribution to do this. Edit the line #define HAYES 0 to #define HAYES 1. Then make and make install. Everything works nicely after that. How am I expected to enter these AT commands? Make what is called a direct entry in your /etc/remote file (see &man.remote.5;). For example, if your modem is hooked up to the first serial port, /dev/cuaa0, then put in the following line: cuaa0:dv=/dev/cuaa0:br#19200:pa=none Use the highest bps rate your modem supports in the br capability. Then, type tip cuaa0 (see &man.tip.1;) and you will be connected to your modem. If there is no /dev/cuaa0 on your system, do this: &prompt.root; cd /dev &prompt.root; sh MAKEDEV cuaa0 Or use cu as root with the following command: &prompt.root; cu -lline -sspeed with line being the serial port (e.g. /dev/cuaa0) and speed being the speed (e.g.57600). When you are done entering the AT commands hit ~. to exit. Why does the <@> sign for the pn capability not work? The <@> sign in the phone number capability tells tip to look in /etc/phones for a phone number. But the <@> sign is also a special character in capability files like /etc/remote. Escape it with a backslash: pn=\@ How can I dial a phone number on the command line? Put what is called a generic entry in your /etc/remote file (see &man.remote.5;). For example: tip115200|Dial any phone number at 115200 bps:\ :dv=/dev/cuaa0:br#115200:at=hayes:pa=none:du: tip57600|Dial any phone number at 57600 bps:\ :dv=/dev/cuaa0:br#57600:at=hayes:pa=none:du: Then you can do something like tip -115200 5551234. If you prefer &man.cu.1; over &man.tip.1;, use a generic cu entry: cu115200|Use cu to dial any number at 115200bps:\ :dv=/dev/cuaa1:br#57600:at=hayes:pa=none:du: and type cu 5551234 -s 115200. Do I have to type in the bps rate every time I do that? Put in an entry for tip1200 or cu1200, but go ahead and use whatever bps rate is appropriate with the br capability. &man.tip.1; thinks a good default is 1200 bps which is why it looks for a tip1200 entry. You do not have to use 1200 bps, though. How can I more easily access a number of hosts through a terminal server? Rather than waiting until you are connected and typing CONNECT host each time, use tip's cm capability. For example, these entries in /etc/remote (see &man.remote.5;): pain|pain.deep13.com|Forrester's machine:\ :cm=CONNECT pain\n:tc=deep13: muffin|muffin.deep13.com|Frank's machine:\ :cm=CONNECT muffin\n:tc=deep13: deep13:Gizmonics Institute terminal server:\ :dv=/dev/cuaa2:br#38400:at=hayes:du:pa=none:pn=5551234: will let you type tip pain or tip muffin to connect to the hosts pain or muffin; and tip deep13 to get to the terminal server. Can tip try more than one line for each site? This is often a problem where a university has several modem lines and several thousand students trying to use them... Make an entry for your university in /etc/remote (see &man.remote.5;) and use <\@> for the pn capability: big-university:\ :pn=\@:tc=dialout dialout:\ :dv=/dev/cuaa3:br#9600:at=courier:du:pa=none: Then, list the phone numbers for the university in /etc/phones (see &man.phones.5;): big-university 5551111 big-university 5551112 big-university 5551113 big-university 5551114 &man.tip.1; will try each one in the listed order, then give up. If you want to keep retrying, run &man.tip.1; in a while loop. Why do I have to hit CTRLP twice to send CTRLP once? CTRLP is the default force character, used to tell &man.tip.1; that the next character is literal data. You can set the force character to any other character with the ~s escape, which means set a variable. Type ~sforce=single-char followed by a newline. single-char is any single character. If you leave out single-char, then the force character is the nul character, which you can get by typing CTRL2 or CTRLSPACE. A pretty good value for single-char is SHIFTCTRL6, which I have seen only used on some terminal servers. You can have the force character be whatever you want by specifying the following in your $HOME/.tiprc file: force=single-char Why is everything I type suddenly in UPPER CASE? You must have pressed CTRLA, &man.tip.1; raise character, specially designed for people with broken Caps Lock keys. Use ~s as above and set the variable raisechar to something reasonable. In fact, you can set it to the same as the force character, if you never expect to use either of these features. Here is a sample .tiprc file perfect for Emacs users who need to type CTRL2 and CTRLA a lot: force=^^ raisechar=^^ The ^^ is SHIFTCTRL6. How can I do file transfers with tip? If you are talking to another Unix system, you can send and receive files with ~p (put) and ~t (take). These commands run &man.cat.1; and &man.echo.1; on the remote system to accept and send files. The syntax is: ~p <local-file> [<remote-file>] ~t <remote-file> [<local-file>] There is no error checking, so you probably should use another protocol, like zmodem. How can I run zmodem with tip? First, install one of the zmodem programs from the ports collection (such as one of the two from the comms category, lrzsz or rzsz. To receive files, start the sending program on the remote end. Then, press enter and type ~C rz (or ~C lrz if you installed lrzsz) to begin receiving them locally. To send files, start the receiving program on the remote end. Then, press enter and type ~C sz files (or ~C lsz files) to send them to the remote system. Miscellaneous Questions FreeBSD uses far more swap space than Linux. Why? FreeBSD only appears to use more swap than Linux. In actual fact, it does not. The main difference between FreeBSD and Linux in this regard is that FreeBSD will proactively move entirely idle, unused pages of main memory into swap in order to make more main memory available for active use. Linux tends to only move pages to swap as a last resort. The perceived heavier use of swap is balanced by the more efficient use of main memory. Note that while FreeBSD is proactive in this regard, it does not arbitrarily decide to swap pages when the system is truly idle. Thus you will not find your system all paged out when you get up in the morning after leaving it idle overnight. Why does top show very little free memory even when I have very few programs running? The simple answer is that free memory is wasted memory. Any memory that your programs do not actively allocate is used within the FreeBSD kernel as disk cache. The values shown by &man.top.1; labeled as Inact, Cache, and Buf are all cached data at different aging levels. This cached data means the system does not have to access a slow disk again for data it has accessed recently, thus increasing overall performance. In general, a low value shown for Free memory in &man.top.1; is good, provided it is not very low. Why will chmod not change the permissions on symlinks? Symlinks do not have permissions, and by default, &man.chmod.1; will not follow symlinks to change the permissions on the target file. So if you have a file, foo, and a symlink to that file, bar, then this command will always succeed. &prompt.user; chmod g-w bar However, the permissions on foo will not have changed. You have to use either or together with the option to make this work. See the &man.chmod.1; and &man.symlink.7; manual pages for more info. The option does a RECURSIVE &man.chmod.1;. Be careful about specifying directories or symlinks to directories to &man.chmod.1;. If you want to change the permissions of a directory referenced by a symlink, use &man.chmod.1; without any options and follow the symlink with a trailing slash (/). For example, if foo is a symlink to directory bar, and you want to change the permissions of foo (actually bar), you would do something like: &prompt.user; chmod 555 foo/ With the trailing slash, &man.chmod.1; will follow the symlink, foo, to change the permissions of the directory, bar. Can I run DOS binaries under FreeBSD? Yes, you can use the integrated doscmd DOS emulation program to run a subset of DOS commands. If doscmd will not suffice, the add-on utility pcemu emulates an 8088 and enough BIOS services to run many DOS text mode applications. It requires the X Window System. What do I need to do to translate a FreeBSD document into my native language? See the Translation FAQ in the FreeBSD Documentation Project Primer. Why does my email to any address at FreeBSD.org bounce? The FreeBSD.org mail system implements some of the stricter Postfix checks on incoming mail and rejects mail that is either misconfigured or is potential spam. Your mail might bounce for one of the following reasons: The email is being sent from a known spam domain or IP block. The FreeBSD mail servers reject email from known spam sources. If you have service through a company or domain who generates or relays spam, please switch to a service provider who does not. The body of the email only contains HTML. Mail should be sent in plain text only. Please configure your mail user agent to send plain text. The mailer at FreeBSD.org cannot resolve the IP address of the connecting host back to a symbolic name. Working reverse DNS is a standard requirement for accepting mail from a host. Set up reverse DNS for your mail server's IP address. Many home services (DSL, cable, dialup, etc.) will not give you this option. In this case, relay your email through your service provider's mail server. The hostname given in the EHLO/HELO part of the SMTP exchange cannot be resolved to an IP address. A fully qualified, resolvable host name is necessary in this part of the SMTP dialogue before mail will be accepted. If you do not have a host name that is registered in the DNS, then you should use your service provider's mail server to relay your mail. Your message had a message ID ending with the string localhost. Some mail user agents generate bad message IDs which will not be accepted. You will need to persuade your mail user agent to generate a valid message ID or else configure your mail transfer agent to rewrite them. Where can I find a free FreeBSD account? While FreeBSD does not provide open access to any of their servers, others do provide open access Unix systems. The charge varies and limited services may be available. Arbornet, Inc, also known as M-Net, has been providing open access to Unix systems since 1983. Starting on an Altos running System III, the site switched to BSD/OS in 1991. In June of 2000, the site switched again to FreeBSD. M-Net can be accessed via telnet and SSH and provides basic access to the entire FreeBSD software suite. However, network access is limited to members and patrons who donate to the system, which is run as a non-profit organization. M-Net also provides an bulletin board system and interactive chat. Grex provides a site very similar to M-Net including the same bulletin board and interactive chat software. However, the machine is a Sun 4M and is running SunOS What is sup, and how do I use it? SUP stands for Software Update Protocol, and was developed by CMU for keeping their development trees in sync. We used it to keep remote sites in sync with our central development sources. SUP is not bandwidth friendly, and has been retired. The current recommended method to keep your sources up to date is CVSup What is the cute little red guy's name? He does not have one, and is just called the BSD daemon. If you insist upon using a name, call him beastie. Note that beastie is pronounced BSD. You can learn more about the BSD daemon on his home page. Can I use the BSD daemon image? Perhaps. The BSD daemon is copyrighted by Marshall Kirk McKusick. You will want to check his Statement on the Use of the BSD Daemon Figure for detailed usage terms. In summary, you are free to use the image in a tasteful manner, for personal use, so long as appropriate credit is given. If you want to use him commercially, you must contact Kirk McKusick. More details are available on the BSD Daemon's home page. Do you have any BSD daemon images I could use? You will find eps and Xfig drawings under /usr/share/examples/BSD_daemon/. What does MFC mean? MFC is an acronym for Merged From -CURRENT. It is used in the CVS logs to denote when a change was migrated from the CURRENT to the STABLE branches. What does BSD mean? It stands for something in a secret language that only members can know. It does not translate literally but its ok to tell you that BSD's translation is something between, Formula-1 Racing Team, Penguins are tasty snacks, and We have a better sense of humor than Linux. :-) Seriously, BSD is an acronym for Berkeley Software Distribution, which is the name the Berkeley CSRG (Computer Systems Research Group) chose for their Unix distribution way back when. What does POLA mean? Principle of Least Astonishment. It means that as FreeBSD evolves, changes visible to the user should be kept as unsurprising as possible. For example, arbitrarily rearranging system startup variables in /etc/defaults/rc.conf violates POLA. Developers consider POLA when contemplating user-visible system changes. What is a repo-copy? A repo-copy (which is a short form of repository copy) refers to the direct copying of files within the CVS repository. Without a repo-copy, if a file needed to be copied or moved to another place in the repository, the committer would run cvs add to put the file in its new location, and then cvs rm on the old file if the old copy was being removed. The disadvantage of this method is that the history (i.e. the entries in the CVS logs) of the file would not be copied to the new location. As the FreeBSD Project considers this history very useful, a repository copy is often used instead. This is a process where one of the repository meisters will copy the files directly within the repository, rather than using the &man.cvs.1; program. Why should I care what color the bikeshed is? The really, really short answer is that you should not. The somewhat longer answer is that just because you are capable of building a bikeshed does not mean you should stop others from building one just because you do not like the color they plan to paint it. This is a metaphor indicating that you need not argue about every little feature just because you know enough to do so. Some people have commented that the amount of noise generated by a change is inversely proportional to the complexity of the change. The longer and more complete answer is that after a very long argument about whether &man.sleep.1; should take fractional second arguments, &a.phk; posted a long message entitled A bike shed (any colour will do) on greener grass.... The appropriate portions of that message are quoted below.
&a.phk; on freebsd-hackers, October 2, 1999 What is it about this bike shed? Some of you have asked me. It is a long story, or rather it is an old story, but it is quite short actually. C. Northcote Parkinson wrote a book in the early 1960s, called Parkinson's Law, which contains a lot of insight into the dynamics of management. [snip a bit of commentary on the book] In the specific example involving the bike shed, the other vital component is an atomic power-plant, I guess that illustrates the age of the book. Parkinson shows how you can go into the board of directors and get approval for building a multi-million or even billion dollar atomic power plant, but if you want to build a bike shed you will be tangled up in endless discussions. Parkinson explains that this is because an atomic plant is so vast, so expensive and so complicated that people cannot grasp it, and rather than try, they fall back on the assumption that somebody else checked all the details before it got this far. Richard P. Feynmann gives a couple of interesting, and very much to the point, examples relating to Los Alamos in his books. A bike shed on the other hand. Anyone can build one of those over a weekend, and still have time to watch the game on TV. So no matter how well prepared, no matter how reasonable you are with your proposal, somebody will seize the chance to show that he is doing his job, that he is paying attention, that he is here. In Denmark we call it setting your fingerprint. It is about personal pride and prestige, it is about being able to point somewhere and say There! I did that. It is a strong trait in politicians, but present in most people given the chance. Just think about footsteps in wet cement.
The FreeBSD Funnies How cool is FreeBSD? Q. Has anyone done any temperature testing while running FreeBSD? I know Linux runs cooler than DOS, but have never seen a mention of FreeBSD. It seems to run really hot. A. No, but we have done numerous taste tests on blindfolded volunteers who have also had 250 micrograms of LSD-25 administered beforehand. 35% of the volunteers said that FreeBSD tasted sort of orange, whereas Linux tasted like purple haze. Neither group mentioned any significant variances in temperature. We eventually had to throw the results of this survey out entirely anyway when we found that too many volunteers were wandering out of the room during the tests, thus skewing the results. We think most of the volunteers are at Apple now, working on their new scratch and sniff GUI. It is a funny old business we are in! Seriously, both FreeBSD and Linux use the HLT (halt) instruction when the system is idle thus lowering its energy consumption and therefore the heat it generates. Also if you have APM (advanced power management) configured, then FreeBSD can also put the CPU into a low power mode. Who is scratching in my memory banks?? Q. Is there anything odd that FreeBSD does when compiling the kernel which would cause the memory to make a scratchy sound? When compiling (and for a brief moment after recognizing the floppy drive upon startup, as well), a strange scratchy sound emanates from what appears to be the memory banks. A. Yes! You will see frequent references to daemons in the BSD documentation, and what most people do not know is that this refers to genuine, non-corporeal entities that now possess your computer. The scratchy sound coming from your memory is actually high-pitched whispering exchanged among the daemons as they best decide how to deal with various system administration tasks. If the noise gets to you, a good fdisk /mbr from DOS will get rid of them, but do not be surprised if they react adversely and try to stop you. In fact, if at any point during the exercise you hear the satanic voice of Bill Gates coming from the built-in speaker, take off running and do not ever look back! Freed from the counterbalancing influence of the BSD daemons, the twin demons of DOS and Windows are often able to re-assert total control over your machine to the eternal damnation of your soul. Now that you know, given a choice you would probably prefer to get used to the scratchy noises, no? How many FreeBSD hackers does it take to change a lightbulb? One thousand, one hundred and sixty-nine: Twenty-three to complain to -CURRENT about the lights being out; Four to claim that it is a configuration problem, and that such matters really belong on -questions; Three to submit PRs about it, one of which is misfiled under doc and consists only of it's dark; One to commit an untested lightbulb which breaks buildworld, then back it out five minutes later; Eight to flame the PR originators for not including patches in their PRs; Five to complain about buildworld being broken; Thirty-one to answer that it works for them, and they must have cvsupped at a bad time; One to post a patch for a new lightbulb to -hackers; One to complain that he had patches for this three years ago, but when he sent them to -CURRENT they were just ignored, and he has had bad experiences with the PR system; besides, the proposed new lightbulb is non-reflexive; Thirty-seven to scream that lightbulbs do not belong in the base system, that committers have no right to do things like this without consulting the Community, and WHAT IS -CORE DOING ABOUT IT!? Two hundred to complain about the color of the bicycle shed; Three to point out that the patch breaks &man.style.9;; Seventeen to complain that the proposed new lightbulb is under GPL; Five hundred and eighty-six to engage in a flame war about the comparative advantages of the GPL, the BSD license, the MIT license, the NPL, and the personal hygiene of unnamed FSF founders; Seven to move various portions of the thread to -chat and -advocacy; One to commit the suggested lightbulb, even though it shines dimmer than the old one; Two to back it out with a furious flame of a commit message, arguing that FreeBSD is better off in the dark than with a dim lightbulb; Forty-six to argue vociferously about the backing out of the dim lightbulb and demanding a statement from -core; Eleven to request a smaller lightbulb so it will fit their Tamagotchi if we ever decide to port FreeBSD to that platform; Seventy-three to complain about the SNR on -hackers and -chat and unsubscribe in protest; Thirteen to post unsubscribe, How do I unsubscribe?, or Please remove me from the list, followed by the usual footer; One to commit a working lightbulb while everybody is too busy flaming everybody else to notice; Thirty-one to point out that the new lightbulb would shine 0.364% brighter if compiled with TenDRA (although it will have to be reshaped into a cube), and that FreeBSD should therefore switch to TenDRA instead of GCC; One to complain that the new lightbulb lacks fairings; Nine (including the PR originators) to ask what is MFC?; Fifty-seven to complain about the lights being out two weeks after the bulb has been changed. &a.nik; adds: I was laughing quite hard at this. And then I thought, Hang on, shouldn't there be '1 to document it.' in that list somewhere? And then I was enlightened :-) Where does data written to /dev/null go? It goes into a special data sink in the CPU where it is converted to heat which is vented through the heatsink / fan assembly. This is why CPU cooling is increasingly important; as people get used to faster processors, they become careless with their data and more and more of it ends up in /dev/null, overheating their CPUs. If you delete /dev/null (which effectively disables the CPU data sink) your CPU may run cooler but your system will quickly become constipated with all that excess data and start to behave erratically. If you have a fast network connection you can cool down your CPU by reading data out of /dev/random and sending it off somewhere; however you run the risk of overheating your network connection and / or angering your ISP, as most of the data will end up getting converted to heat by their equipment, but they generally have good cooling, so if you do not overdo it you should be OK. Paul Robinson adds: There are other methods. As every good sysadmin knows, it is part of standard practise to send data to the screen of interesting variety to keep all the pixies that make up your picture happy. Screen pixies (commonly mis-typed or re-named as 'pixels') are categorised by the type of hat they wear (red, green or blue) and will hide or appear (thereby showing the colour of their hat) whenever they receive a little piece of food. Video cards turn data into pixie-food, and then send them to the pixies - the more expensive the card, the better the food, so the better behaved the pixies are. They also need constant stimulation - this is why screen savers exist. To take your suggestions further, you could just throw the random data to console, thereby letting the pixies consume it. This causes no heat to be produced at all, keeps the pixies happy and gets rid of your data quite quickly, even if it does make things look a bit messy on your screen. Incidentally, as an ex-admin of a large ISP who experienced many problems attempting to maintain a stable temperature in a server room, I would strongly discourage people sending the data they do not want out to the network. The fairies who do the packet switching and routing get annoyed by it as well. Advanced Topics How can I learn more about FreeBSD's internals? At this time, there is no book on FreeBSD-specific OS internals. Much general &unix; knowledge is directly applicable to FreeBSD, however. Additionally, there are BSD-specific books that are still relevant. For a list, please check the Handbook's Operating System Internals Bibliography. How can I contribute to FreeBSD? Please see the article on Contributing to FreeBSD for specific advice on how to do this. Assistance is more than welcome! What are SNAPs and RELEASEs? There are currently three active/semi-active branches in the FreeBSD CVS Repository. (Earlier branches are only changed very rarely, which is why there are only three active branches of development): RELENG_3 AKA 3.X-STABLE RELENG_4 AKA 4-STABLE HEAD AKA -CURRENT AKA 5.0-CURRENT HEAD is not an actual branch tag, like the other two; it is simply a symbolic constant for the current, non-branched development stream which we simply refer to as -CURRENT. Right now, -CURRENT is the 5.0 development stream and the 4-STABLE branch, RELENG_4, forked off from -CURRENT in Mar 2000. How do I make my own custom release? Please see the Release Engineering article. Why does make world clobber my existing installed binaries? Yes, this is the general idea; as its name might suggest, make world rebuilds every system binary from scratch, so you can be certain of having a clean and consistent environment at the end (which is why it takes so long). If the environment variable DESTDIR is defined while running make world or make install, the newly-created binaries will be deposited in a directory tree identical to the installed one, rooted at ${DESTDIR}. Some random combination of shared libraries modifications and program rebuilds can cause this to fail in make world however. Why does my system say (bus speed defaulted) when it boots? The Adaptec 1542 SCSI host adapters allow the user to configure their bus access speed in software. Previous versions of the 1542 driver tried to determine the fastest usable speed and set the adapter to that. We found that this breaks some users' systems, so you now have to define the TUNE_1542 kernel configuration option in order to have this take place. Using it on those systems where it works may make your disks run faster, but on those systems where it does not, your data could be corrupted. Can I follow -CURRENT with limited Internet access? Yes, you can do this without downloading the whole source tree by using the CTM facility. How did you split the distribution into 240k files? Newer BSD based systems have a option to split that allows them to split files on arbitrary byte boundaries. Here is an example from /usr/src/Makefile. bin-tarball: (cd ${DISTDIR}; \ tar cf - . \ gzip --no-name -9 -c | \ split -b 240640 - \ ${RELEASEDIR}/tarballs/bindist/bin_tgz.) I have written a kernel extension, who do I send it to? Please take a look at the article on Contributing to FreeBSD to learn how to submit code. And thanks for the thought! How are Plug N Play ISA cards detected and initialized? By: Frank Durda IV uhclem@nemesis.lonestar.org In a nutshell, there a few I/O ports that all of the PnP boards respond to when the host asks if anyone is out there. So when the PnP probe routine starts, it asks if there are any PnP boards present, and all the PnP boards respond with their model # to a I/O read of the same port, so the probe routine gets a wired-OR yes to that question. At least one bit will be on in that reply. Then the probe code is able to cause boards with board model IDs (assigned by Microsoft/Intel) lower than X to go off-line. It then looks to see if any boards are still responding to the query. If the answer was 0, then there are no boards with IDs above X. Now probe asks if there are any boards below X. If so, probe knows there are boards with a model numbers below X. Probe then asks for boards greater than X-(limit/4) to go off-line. If repeats the query. By repeating this semi-binary search of IDs-in-range enough times, the probing code will eventually identify all PnP boards present in a given machine with a number of iterations that is much lower than what 2^64 would take. The IDs are two 32-bit fields (hence 2ˆ64) + 8 bit checksum. The first 32 bits are a vendor identifier. They never come out and say it, but it appears to be assumed that different types of boards from the same vendor could have different 32-bit vendor ids. The idea of needing 32 bits just for unique manufacturers is a bit excessive. The lower 32 bits are a serial #, Ethernet address, something that makes this one board unique. The vendor must never produce a second board that has the same lower 32 bits unless the upper 32 bits are also different. So you can have multiple boards of the same type in the machine and the full 64 bits will still be unique. The 32 bit groups can never be all zero. This allows the wired-OR to show non-zero bits during the initial binary search. Once the system has identified all the board IDs present, it will reactivate each board, one at a time (via the same I/O ports), and find out what resources the given board needs, what interrupt choices are available, etc. A scan is made over all the boards to collect this information. This info is then combined with info from any ECU files on the hard disk or wired into the MLB BIOS. The ECU and BIOS PnP support for hardware on the MLB is usually synthetic, and the peripherals do not really do genuine PnP. However by examining the BIOS info plus the ECU info, the probe routines can cause the devices that are PnP to avoid those devices the probe code cannot relocate. Then the PnP devices are visited once more and given their I/O, DMA, IRQ and Memory-map address assignments. The devices will then appear at those locations and remain there until the next reboot, although there is nothing that says you cannot move them around whenever you want. There is a lot of oversimplification above, but you should get the general idea. Microsoft took over some of the primary printer status ports to do PnP, on the logic that no boards decoded those addresses for the opposing I/O cycles. I found a genuine IBM printer board that did decode writes of the status port during the early PnP proposal review period, but MS said tough. So they do a write to the printer status port for setting addresses, plus that use that address + 0x800, and a third I/O port for reading that can be located anywhere between 0x200 and 0x3ff. Can you assign a major number for a device driver I have written? &os.current; after February 2003 has a facility for dynamically and automatically allocating major numbers for device drivers at runtime. This mechanism is highly preferred to the older procedure of statically allocating device numbers. Some comments on this subject can be found in src/sys/conf/majors. If you are forced for some reason to use a static major number, the procedure for obtaining one depends on whether or not you plan on making the driver publicly available. If you do, then please send us a copy of the driver source code, plus the appropriate modifications to files.i386, a sample configuration file entry, and the appropriate &man.MAKEDEV.8; code to create any special files your device uses. If you do not, or are unable to because of licensing restrictions, then character major number 32 and block major number 8 have been reserved specifically for this purpose; please use them. In any case, we would appreciate hearing about your driver on the &a.hackers;. What about alternative layout policies for directories? In answer to the question of alternative layout policies for directories, the scheme that is currently in use is unchanged from what I wrote in 1983. I wrote that policy for the original fast filesystem, and never revisited it. It works well at keeping cylinder groups from filling up. As several of you have noted, it works poorly for find. Most filesystems are created from archives that were created by a depth first search (aka ftw). These directories end up being striped across the cylinder groups thus creating a worst possible scenario for future depth first searches. If one knew the total number of directories to be created, the solution would be to create (total / fs_ncg) per cylinder group before moving on. Obviously, one would have to create some heuristic to guess at this number. Even using a small fixed number like say 10 would make an order of magnitude improvement. To differentiate restores from normal operation (when the current algorithm is probably more sensible), you could use the clustering of up to 10 if they were all done within a ten second window. Anyway, my conclusion is that this is an area ripe for experimentation. Kirk McKusick, September 1998 How can I make the most of the data I see when my kernel panics? [This section was extracted from a mail written by &a.wpaul; on the freebsd-current mailing list by &a.des;, who fixed a few typos and added the bracketed comments] From: Bill Paul <wpaul@skynet.ctr.columbia.edu> Subject: Re: the fs fun never stops To: Ben Rosengart Date: Sun, 20 Sep 1998 15:22:50 -0400 (EDT) Cc: current@FreeBSD.org Ben Rosengart posted the following panic message] > Fatal trap 12: page fault while in kernel mode > fault virtual address = 0x40 > fault code = supervisor read, page not present > instruction pointer = 0x8:0xf014a7e5 ^^^^^^^^^^ > stack pointer = 0x10:0xf4ed6f24 > frame pointer = 0x10:0xf4ed6f28 > code segment = base 0x0, limit 0xfffff, type 0x1b > = DPL 0, pres 1, def32 1, gran 1 > processor eflags = interrupt enabled, resume, IOPL = 0 > current process = 80 (mount) > interrupt mask = > trap number = 12 > panic: page fault [When] you see a message like this, it is not enough to just reproduce it and send it in. The instruction pointer value that I highlighted up there is important; unfortunately, it is also configuration dependent. In other words, the value varies depending on the exact kernel image that you are using. If you are using a GENERIC kernel image from one of the snapshots, then it is possible for somebody else to track down the offending function, but if you are running a custom kernel then only you can tell us where the fault occurred. What you should do is this: Write down the instruction pointer value. Note that the 0x8: part at the beginning is not significant in this case: it is the 0xf0xxxxxx part that we want. When the system reboots, do the following: &prompt.user; nm -n /kernel.that.caused.the.panic | grep f0xxxxxx where f0xxxxxx is the instruction pointer value. The odds are you will not get an exact match since the symbols in the kernel symbol table are for the entry points of functions and the instruction pointer address will be somewhere inside a function, not at the start. If you do not get an exact match, omit the last digit from the instruction pointer value and try again, i.e.: &prompt.user; nm -n /kernel.that.caused.the.panic | grep f0xxxxx If that does not yield any results, chop off another digit. Repeat until you get some sort of output. The result will be a possible list of functions which caused the panic. This is a less than exact mechanism for tracking down the point of failure, but it is better than nothing. I see people constantly show panic messages like this but rarely do I see someone take the time to match up the instruction pointer with a function in the kernel symbol table. The best way to track down the cause of a panic is by capturing a crash dump, then using &man.gdb.1; to generate a stack trace on the crash dump. In any case, the method I normally use is this: Set up a kernel config file, optionally adding options DDB if you think you need the kernel debugger for something. (I use this mainly for setting breakpoints if I suspect an infinite loop condition of some kind.) Use config -g KERNELCONFIG to set up the build directory. cd /sys/compile/ KERNELCONFIG; make Wait for kernel to finish compiling. make install reboot The &man.make.1; process will have built two kernels. kernel and kernel.debug. kernel was installed as /kernel, while kernel.debug can be used as the source of debugging symbols for &man.gdb.1;. To make sure you capture a crash dump, you need edit /etc/rc.conf and set dumpdev to point to your swap partition. This will cause the &man.rc.8; scripts to use the &man.dumpon.8; command to enable crash dumps. You can also run &man.dumpon.8; manually. After a panic, the crash dump can be recovered using &man.savecore.8;; if dumpdev is set in /etc/rc.conf, the &man.rc.8; scripts will run &man.savecore.8; automatically and put the crash dump in /var/crash. FreeBSD crash dumps are usually the same size as the physical RAM size of your machine. That is, if you have 64MB of RAM, you will get a 64MB crash dump. Therefore you must make sure there is enough space in /var/crash to hold the dump. Alternatively, you run &man.savecore.8; manually and have it recover the crash dump to another directory where you have more room. It is possible to limit the size of the crash dump by using options MAXMEM=(foo) to set the amount of memory the kernel will use to something a little more sensible. For example, if you have 128MB of RAM, you can limit the kernel's memory usage to 16MB so that your crash dump size will be 16MB instead of 128MB. Once you have recovered the crash dump, you can get a stack trace with &man.gdb.1; as follows: &prompt.user; gdb -k /sys/compile/KERNELCONFIG/kernel.debug /var/crash/vmcore.0 (gdb) where Note that there may be several screens worth of information; ideally you should use &man.script.1; to capture all of them. Using the unstripped kernel image with all the debug symbols should show the exact line of kernel source code where the panic occurred. Usually you have to read the stack trace from the bottom up in order to trace the exact sequence of events that lead to the crash. You can also use &man.gdb.1; to print out the contents of various variables or structures in order to examine the system state at the time of the crash. Now, if you are really insane and have a second computer, you can also configure &man.gdb.1; to do remote debugging such that you can use &man.gdb.1; on one system to debug the kernel on another system, including setting breakpoints, single-stepping through the kernel code, just like you can do with a normal user-mode program. I have not played with this yet as I do not often have the chance to set up two machines side by side for debugging purposes. [Bill adds: "I forgot to mention one thing: if you have DDB enabled and the kernel drops into the debugger, you can force a panic (and a crash dump) just by typing 'panic' at the ddb prompt. It may stop in the debugger again during the panic phase. If it does, type 'continue' and it will finish the crash dump." -ed] Why has dlsym() stopped working for ELF executables? The ELF toolchain does not, by default, make the symbols defined in an executable visible to the dynamic linker. Consequently dlsym() searches on handles obtained from calls to dlopen(NULL, flags) will fail to find such symbols. If you want to search, using dlsym(), for symbols present in the main executable of a process, you need to link the executable using the option to the ELF linker (&man.ld.1;). How can I increase or reduce the kernel address space? By default, the kernel address space is 256 MB on FreeBSD 3.X and 1 GB on FreeBSD 4.X. If you run a network-intensive server (e.g. a large FTP or HTTP server), you might find that 256 MB is not enough. So how do you increase the address space? There are two aspects to this. First, you need to tell the kernel to reserve a larger portion of the address space for itself. Second, since the kernel is loaded at the top of the address space, you need to lower the load address so it does not bump its head against the ceiling. The first goal is achieved by increasing the value of NKPDE in src/sys/i386/include/pmap.h. Here is what it looks like for a 1 GB address space: #ifndef NKPDE #ifdef SMP #define NKPDE 254 /* addressable number of page tables/pde's */ #else #define NKPDE 255 /* addressable number of page tables/pde's */ #endif /* SMP */ #endif To find the correct value of NKPDE, divide the desired address space size (in megabytes) by four, then subtract one for UP and two for SMP. To achieve the second goal, you need to compute the correct load address: simply subtract the address space size (in bytes) from 0x100100000; the result is 0xc0100000 for a 1 GB address space. Set LOAD_ADDRESS in src/sys/i386/conf/Makefile.i386 to that value; then set the location counter in the beginning of the section listing in src/sys/i386/conf/kernel.script to the same value, as follows: OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386") OUTPUT_ARCH(i386) ENTRY(btext) SEARCH_DIR(/usr/lib); SEARCH_DIR(/usr/obj/elf/home/src/tmp/usr/i386-unknown-freebsdelf/lib); SECTIONS { /* Read-only sections, merged into text segment: */ . = 0xc0100000 + SIZEOF_HEADERS; .interp : { *(.interp) } Then reconfig and rebuild your kernel. You will probably have problems with &man.ps.1; &man.top.1; and the like; make world should take care of it (or a manual rebuild of libkvm, &man.ps.1; and &man.top.1; after copying the patched pmap.h to /usr/include/vm/. NOTE: the size of the kernel address space must be a multiple of four megabytes. [&a.dg; adds: I think the kernel address space needs to be a power of two, but I am not certain about that. The old(er) boot code used to monkey with the high order address bits and I think expected at least 256MB granularity.] Acknowledgments
FreeBSD Core Team If you see a problem with this FAQ, or wish to submit an entry, please mail the &a.doc;. We appreciate your feedback, and cannot make this a better FAQ without your help!
&a.jkh; Occasional fits of FAQ-reshuffling and updating. &a.dwhite; Services above and beyond the call of duty on freebsd-questions &a.joerg; Services above and beyond the call of duty on Usenet &a.wollman; Networking and formatting Jim Lowe Multicast information &a.pds; FreeBSD FAQ typing machine slavey The FreeBSD Team Kvetching, moaning, submitting data And to any others we have forgotten, apologies and heartfelt thanks! &bibliography;