Index: check-missing-freebsd-syscalls.py
===================================================================
--- /dev/null
+++ check-missing-freebsd-syscalls.py
@@ -0,0 +1,87 @@
+#!/usr/bin/env python3
+import argparse
+import os
+import io
+import subprocess
+import glob
+import re
+from pathlib import Path
+from os.path import dirname, abspath
+
+
+def collect_all_syscalls(freebsd_path, syscalls):
+    # Find all FreeBSD system calls
+    p1 = subprocess.Popen(["awk", '/#define/{ print $2 }', f'{freebsd_path}/sys/sys/syscall.h'], stdout=subprocess.PIPE)
+    p2 = subprocess.Popen(["cut", '-d', '_', '-f', '2-'], stdin=p1.stdout, stdout=subprocess.PIPE)
+    p1.stdout.close()
+    for syscall in io.TextIOWrapper(p2.stdout, encoding='utf-8'):
+        syscalls.add(syscall[:-1])
+    p2.stdout.close()
+
+def collect_all_ioctls(freebsd_path, ioctls):
+    # Find all pseudo FreeBSD system calls (ioctls)
+    for path in Path(freebsd_path).rglob('*.h'):
+        with io.open(path, 'r', encoding='utf-8', errors='ignore') as header:
+            for line in header:
+                prog = re.match(r'^#define\s+(.*)\s+.*_IOW?R?\(.*\)', line)
+                if prog:
+                    ioctls.add(prog[1])
+
+def collect_implemented_syscalls(implemented_syscalls):
+    # Find implemented system calls in Syzkaller
+    for path in glob.glob("*.txt"):
+        with open(path, 'r') as reader:
+            for line in reader:
+                prog = re.match(r'(\w+)[$(]', line)
+                if prog:
+                    implemented_syscalls.add(prog[1])
+
+def collect_implemented_ioctls(implemented_ioctls):
+    # Find implemented ioctls in Syzkaller
+    for path in glob.glob("*.txt"):
+        with open(path, 'r') as reader:
+            for line in reader:
+                io = re.match(r'ioctl\$(\w+)\(', line)
+                if io:
+                    implemented_ioctls.add(io[1])
+
+def output_syscall_results(syscalls, implemented_syscalls):
+    # Output missing system calls or ioctls
+    diff = sorted(syscalls.difference(implemented_syscalls))
+    print(f'****Syscalls: {len(diff)}****')
+    for missing_syscall in diff:
+        print(missing_syscall)
+
+def output_ioctl_results(ioctls, implemented_ioctls):
+    # Output missing system calls or ioctls
+    diff = sorted(ioctls.difference(implemented_ioctls))
+    print(f'****Ioctls: {len(diff)}****')
+    for missing_syscall in diff:
+        print(missing_syscall)
+
+def main():
+    parser = argparse.ArgumentParser(prog='freebsd_missing_syscall_checker', description='Prints missing FreeBSD syscalls.')
+    parser.add_argument('-s', '--syscall', action='store_true', help='Print missing syscalls.')
+    parser.add_argument('-i', '--ioctl', action='store_true', help='Print missing ioctls.')
+    parser.add_argument('-p', '--path', required=True, help='Path of FreeBSD src checkout.')
+    args = parser.parse_args()
+
+    if not(args.syscall or args.ioctl):
+        parser.error('No action requested, add -s or -i.')
+
+    os.chdir(dirname(dirname(abspath(__file__))) + '/sys/freebsd')
+    if args.syscall:
+        syscalls = set()
+        implemented_syscalls = set()
+        collect_all_syscalls(args.path, syscalls)
+        collect_implemented_syscalls(implemented_syscalls)
+        output_syscall_results(syscalls, implemented_syscalls)
+    if args.ioctl:
+        ioctls = set()
+        implemented_ioctls = set()
+        collect_all_ioctls(args.path, ioctls)
+        collect_implemented_ioctls(implemented_ioctls)
+        output_ioctl_results(ioctls, implemented_ioctls)
+
+if __name__ == "__main__":
+    main()