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kern_conf.c
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kern_conf.c
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/*-
* Parts Copyright (c) 1995 Terrence R. Lambert
* Copyright (c) 1995 Julian R. Elischer
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Terrence R. Lambert.
* 4. The name Terrence R. Lambert may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``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 THE TERRENCE R. LAMBERT 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 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/queue.h>
#include <sys/ctype.h>
#include <machine/stdarg.h>
#define cdevsw_ALLOCSTART (NUMCDEVSW/2)
struct cdevsw *cdevsw[NUMCDEVSW];
static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
/*
* This is the number of hash-buckets. Experiements with 'real-life'
* udev_t's show that a prime halfway between two powers of two works
* best.
*/
#define DEVT_HASH 83
/* The number of dev_t's we can create before malloc(9) kick in. */
#define DEVT_STASH 50
static struct specinfo devt_stash[DEVT_STASH];
static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH];
static LIST_HEAD(, specinfo) dev_free;
devfs_create_t *devfs_create_hook;
devfs_destroy_t *devfs_destroy_hook;
int devfs_present;
static int free_devt;
SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
struct cdevsw *
devsw(dev_t dev)
{
if (dev->si_devsw)
return (dev->si_devsw);
return(cdevsw[major(dev)]);
}
/*
* Add a cdevsw entry
*/
int
cdevsw_add(struct cdevsw *newentry)
{
if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
newentry->d_name, newentry->d_maj);
return (EINVAL);
}
if (cdevsw[newentry->d_maj]) {
printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
newentry->d_name, cdevsw[newentry->d_maj]->d_name);
}
cdevsw[newentry->d_maj] = newentry;
return (0);
}
/*
* Remove a cdevsw entry
*/
int
cdevsw_remove(struct cdevsw *oldentry)
{
if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
oldentry->d_name, oldentry->d_maj);
return EINVAL;
}
cdevsw[oldentry->d_maj] = NULL;
return 0;
}
/*
* dev_t and u_dev_t primitives
*/
int
major(dev_t x)
{
if (x == NODEV)
return NOUDEV;
return((x->si_udev >> 8) & 0xff);
}
int
minor(dev_t x)
{
if (x == NODEV)
return NOUDEV;
return(x->si_udev & 0xffff00ff);
}
int
dev2unit(dev_t x)
{
int i;
if (x == NODEV)
return NOUDEV;
i = minor(x);
return ((i & 0xff) | (i >> 8));
}
int
unit2minor(int unit)
{
KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
return ((unit & 0xff) | ((unit << 8) & ~0xffff));
}
static dev_t
allocdev(void)
{
static int stashed;
struct specinfo *si;
if (stashed >= DEVT_STASH) {
MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
M_USE_RESERVE | M_ZERO);
} else if (LIST_FIRST(&dev_free)) {
si = LIST_FIRST(&dev_free);
LIST_REMOVE(si, si_hash);
} else {
si = devt_stash + stashed++;
si->si_flags |= SI_STASHED;
}
LIST_INIT(&si->si_names);
TAILQ_INIT(&si->si_snapshots);
return (si);
}
dev_t
makedev(int x, int y)
{
struct specinfo *si;
udev_t udev;
int hash;
if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
panic("makedev of NOUDEV");
udev = (x << 8) | y;
hash = udev % DEVT_HASH;
LIST_FOREACH(si, &dev_hash[hash], si_hash) {
if (si->si_udev == udev)
return (si);
}
si = allocdev();
si->si_udev = udev;
LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
return (si);
}
void
freedev(dev_t dev)
{
dev_t adev;
if (!free_devt)
return;
if (SLIST_FIRST(&dev->si_hlist))
return;
if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
return;
while (!LIST_EMPTY(&dev->si_names)) {
adev = LIST_FIRST(&dev->si_names);
adev->si_drv1 = NULL;
freedev(adev);
}
LIST_REMOVE(dev, si_hash);
if (dev->si_flags & SI_STASHED) {
bzero(dev, sizeof(*dev));
LIST_INSERT_HEAD(&dev_free, dev, si_hash);
} else {
FREE(dev, M_DEVT);
}
}
udev_t
dev2udev(dev_t x)
{
if (x == NODEV)
return NOUDEV;
return (x->si_udev);
}
dev_t
udev2dev(udev_t x, int b)
{
if (x == NOUDEV)
return (NODEV);
switch (b) {
case 0:
return makedev(umajor(x), uminor(x));
case 1:
return (NODEV);
default:
Debugger("udev2dev(...,X)");
return NODEV;
}
}
int
uminor(udev_t dev)
{
return(dev & 0xffff00ff);
}
int
umajor(udev_t dev)
{
return((dev & 0xff00) >> 8);
}
udev_t
makeudev(int x, int y)
{
return ((x << 8) | y);
}
dev_t
make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
{
dev_t dev;
va_list ap;
int i;
KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj,
("Invalid minor (%d) in make_dev", minor));
dev = makedev(devsw->d_maj, minor);
if (dev->si_flags & SI_NAMED) {
printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
dev->si_name);
return (dev);
}
va_start(ap, fmt);
i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
dev->si_name[i] = '\0';
va_end(ap);
dev->si_devsw = devsw;
dev->si_uid = uid;
dev->si_gid = gid;
dev->si_mode = perms;
dev->si_flags |= SI_NAMED;
if (devfs_create_hook)
devfs_create_hook(dev);
return (dev);
}
dev_t
make_dev_alias(dev_t pdev, char *fmt, ...)
{
dev_t dev;
va_list ap;
int i;
dev = allocdev();
dev->si_flags |= SI_ALIAS;
dev->si_flags |= SI_NAMED;
dev->si_drv1 = pdev;
LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash);
va_start(ap, fmt);
i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
dev->si_name[i] = '\0';
va_end(ap);
if (devfs_create_hook)
devfs_create_hook(dev);
return (dev);
}
void
destroy_dev(dev_t dev)
{
if (!(dev->si_flags & SI_NAMED)) {
printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
major(dev), minor(dev));
return;
}
if (devfs_destroy_hook)
devfs_destroy_hook(dev);
dev->si_drv1 = 0;
dev->si_drv2 = 0;
dev->si_devsw = 0;
dev->si_flags &= ~SI_NAMED;
dev->si_flags &= ~SI_ALIAS;
freedev(dev);
}
const char *
devtoname(dev_t dev)
{
char *p;
int mynor;
if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
p = dev->si_name;
if (devsw(dev))
sprintf(p, "#%s/", devsw(dev)->d_name);
else
sprintf(p, "#%d/", major(dev));
p += strlen(p);
mynor = minor(dev);
if (mynor < 0 || mynor > 255)
sprintf(p, "%#x", (u_int)mynor);
else
sprintf(p, "%d", mynor);
}
return (dev->si_name);
}
int
dev_stdclone(char *name, char **namep, char *stem, int *unit)
{
int u, i;
i = strlen(stem);
if (bcmp(stem, name, i) != 0)
return (0);
if (!isdigit(name[i]))
return (0);
u = 0;
while (isdigit(name[i])) {
u *= 10;
u += name[i++] - '0';
}
*unit = u;
if (namep)
*namep = &name[i];
if (name[i])
return (2);
return (1);
}
/*
* Helper sysctl for devname(3). We're given a {u}dev_t and return
* the name, if any, registered by the device driver.
*/
static int
sysctl_devname(SYSCTL_HANDLER_ARGS)
{
int error;
udev_t ud;
dev_t dev;
error = SYSCTL_IN(req, &ud, sizeof (ud));
if (error)
return (error);
if (ud == NOUDEV)
return(EINVAL);
dev = makedev(umajor(ud), uminor(ud));
if (dev->si_name[0] == '\0')
error = ENOENT;
else
error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
freedev(dev);
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
NULL, 0, sysctl_devname, "", "devname(3) handler");

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