Computer Science
SYSCALLS(2) Linux Programmer's Manual SYSCALLS(2)
NAME
none - list of all system calls
SYNOPSIS
Linux 2.0 system calls.
DESCRIPTION
As of Linux 2.0.34, there are 164 system calls listed in
/usr/include/asm/unistd.h. This man page lists them (pro-
viding hyperlinks if you read this with a browser).
_llseek(2), _newselect(2), _sysctl(2), access(2), acct(2),
adjtimex(2), afs_syscall, alarm(2), bdflush(2), break,
brk(2), chdir(2), chmod(2), chown(2), chroot(2), clone(2),
close(2), creat(2), create_module(2), delete_module(2),
dup(2), dup2(2), execve(2), exit(2), fchdir(2), fchmod(2),
fchown(2), fcntl(2), fdatasync(2), flock(2), fork(2),
fstat(2), fstatfs(2), fsync(2), ftime, ftruncate(2), get-
_kernel_syms(2), getdents(2), getegid(2), geteuid(2), get-
gid(2), getgroups(2), getitimer(2), getpgid(2), get-
pgrp(2), getpid(2), getppid(2), getpriority(2), get-
rlimit(2), getrusage(2), getsid(2), gettimeofday(2), get-
uid(2), gtty, idle(2), init_module(2), ioctl(2), io-
perm(2), iopl(2), ipc(2), kill(2), link(2), lock,
lseek(2), lstat(2), mkdir(2), mknod(2), mlock(2), mlock-
all(2), mmap(2), modify_ldt(2), mount(2), mprotect(2),
mpx, mremap(2), msync(2), munlock(2), munlockall(2), mun-
map(2), nanosleep(2), nice(2), oldfstat, oldlstat,
oldolduname, oldstat, olduname, open(2), pause(2), person-
ality(2), phys, pipe(2), prof, profil, ptrace(2), quo-
tactl(2), read(2), readdir(2), readlink(2), readv(2),
reboot(2), rename(2), rmdir(2), sched_get_priority_max(2),
sched_get_priority_min(2), sched_getparam(2), sched_get-
scheduler(2), sched_rr_get_interval(2), sched_setparam(2),
sched_setscheduler(2), sched_yield(2), select(2), set-
domainname(2), setfsgid(2), setfsuid(2), setgid(2), set-
groups(2), sethostname(2), setitimer(2), setpgid(2), set-
priority(2), setregid(2), setreuid(2), setrlimit(2), set-
sid(2), settimeofday(2), setuid(2), setup(2), sgetmask(2),
sigaction(2), signal(2), sigpending(2), sigprocmask(2),
sigreturn(2), sigsuspend(2), socketcall(2), ssetmask(2),
stat(2), statfs(2), stime(2), stty, swapoff(2), swapon(2),
symlink(2), sync(2), sysfs(2), sysinfo(2), syslog(2),
time(2), times(2), truncate(2), ulimit, umask(2),
umount(2), uname(2), unlink(2), uselib(2), ustat(2),
utime(2), vhangup(2), vm86(2), wait4(2), waitpid(2),
write(2), writev(2).
Of the above, 5 are obsolete, namely oldfstat, oldlstat,
oldolduname, oldstat and olduname (see also obsolete(2)),
and 11 are unimplemented, namely afs_syscall, break,
ftime, gtty, lock, mpx, phys, prof, profil, stty and
ulimit (see also unimplemented(2)). However, ftime(3),
profil(3) and ulimit(3) exist as library routines. The
slot for phys is in use since 2.1.116 for umount2; phys
will never be implemented.
Roughly speaking, the code belonging to the system call
with number __NR_xxx defined in /usr/include/asm/unistd.h
can be found in the kernel source in the routine
sys_xxx(). (The dispatch table for i386 can be found in
/usr/src/linux/arch/i386/kernel/entry.S.) There are many
exceptions, however, mostly because older system calls
were superseded by newer ones, and this has been treated
somewhat unsystematically. Below the details for Linux
2.0.34.
The defines __NR_oldstat and __NR_stat refer to the rou-
tines sys_stat() and sys_newstat(), and similarly for
fstat and lstat. Similarly, the defines __NR_oldolduname,
__NR_olduname and __NR_uname refer to the routines
sys_olduname(), sys_uname() and sys_newuname(). Thus,
__NR_stat and __NR_uname have always referred to the lat-
est version of the system call, and the older ones are for
backward compatibility.
It is different with select and mmap. These use five or
more parameters, and caused problems the way parameter
passing on the i386 used to be set up. Thus, while other
architectures have sys_select() ans sys_mmap() correspond-
ing to __NR_select and __NR_mmap, on i386 one finds
old_select() and old_mmap() (routines that use a pointer
to a parameter block) instead. These days passing five
parameters is not a problem anymore, and there is a
__NR__newselect (used by libc 6) that corresponds directly
to sys_select().
Two other system call numbers, __NR__llseek and
__NR__sysctl have an additional underscore absent in
sys_llseek() and sys_sysctl().
Then there is __NR_readdir corresponding to old_readdir(),
which will read at most one directory entry at a time, and
is superseded by sys_getdents().
Finally, the system call 166, with entry point sys_vm86()
does not have a symbolic number at all. This version
supersedes sys_vm86old() with number __NR_vm86.
Linux 2.0 12 April 1996 1
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