Linux System Calls

Systemcalls in alphabetical order

System Calls are the calls made from the user space to access the kernel space

_exit - like exit but with fewer actions (m+c)
accept - accept a connection on a socket (m+c!)
access - check user’s permissions for a file (m+c)
acct - not yet implemented (mc)
adjtimex - set/get kernel time variables (-c)
afs syscall - reserved andrew filesystem call (-)
alarm - send SIGALRM at a specified time (m+c)
bdflush - flush dirty buffers to disk (-c)
bind - name a socket for interprocess communication (m!c)
break - not yet implemented (-)
brk - change data segment size (mc)
chdir - change working directory (m+c)
chmod - change file attributes (m+c)
chown - change ownership of a file (m+c)
chroot - set a new root directory (mc)
clone - see fork (m-)
close - close a file by reference (m+c)
connect - link 2 sockets (m!c)
creat - create a file (m+c)
create module - allocate space for a loadable kernel module (-)
delete module - unload a kernel module (-)
dup - create a file descriptor duplicate (m+c)
dup2 - duplicate a file descriptor (m+c)
execl, execlp, execle, ... - see execve (m+!c)
execve - execute a file (m+c)
exit - terminate a program (m+c)
fchdir - change working directory by reference ()
fchmod - see chmod (mc)
fchown - change ownership of a file (mc)
fclose - close a file by reference (m+!c)
fcntl - file/filedescriptor control (m+c)
flock - change file locking (m!c)
fork - create a child process (m+c)
fpathconf - get info about a file by reference (m+!c)
fread - read array of binary data from stream (m+!c)
fstat - get file status (m+c)
fstatfs - get filesystem status by reference (mc)
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fsync - write file cache to disk (mc)
ftime - get timezone+seconds since 1.1.1970 (m!c)
ftruncate - change file size (mc)
fwrite - write array of binary datas to stream (m+!c)
get kernel syms - get kernel symbol table or its size (-)
getdomainname - get system’s domainname (m!c)
getdtablesize - get filedescriptor table size (m!c)
getegid - get effective group id (m+c)
geteuid - get effective user id (m+c)
getgid - get real group id (m+c)
getgroups - get supplemental groups (m+c)
gethostid - get unique host identifier (m!c)
gethostname - get system’s hostname (m!c)
getitimer - get value of interval timer (mc)
getpagesize - get size of a system page (m-!c)
getpeername - get address of a connected peer socket (m!c)
getpgid - get parent group id of a process (+c)
getpgrp - get parent group id of current process (m+c)
getpid - get process id of current process (m+c)
getppid - get process id of the parent process (m+c)
getpriority - get a process/group/user priority (mc)
getrlimit - get resource limits (mc)
getrusage - get usage of resources (m)
getsockname - get the adress of a socket (m!c)
getsockopt - get option settings of a socket (m!c)
gettimeofday - get timezone+seconds since 1.1.1970 (mc)
getuid - get real uid (m+c)
gtty - not yet implemented ()
idle - make a process a candidate for swap (mc)
init module - insert a loadable kernel module (-)
ioctl - manipulate a character device (mc)
ioperm - set some i/o port’s permissions (m-c)
iopl - set all i/o port’s permissions (m-c)
ipc - interprocess communication (-c)
kill - send a signal to a process (m+c)
killpg - send a signal to a process group (mc!)
klog - see syslog (-!)
link - create a hardlink for an existing file (m+c)
listen - listen for socket connections (m!c)
llseek - lseek for large files (-)
lock - not implemented yet ()
lseek - change the position ptr of a file descriptor (m+c)
lstat - get file status (mc)
mkdir - create a directory (m+c)
mknod - create a device (mc)
mmap - map a file into memory (mc)
modify ldt - read or write local descriptor table (-)
mount - mount a filesystem (mc)
mprotect - read, write or execute protect memory (-)
mpx - not implemented yet ()
msgctl - ipc message control (m!c)
msgget - get an ipc message queue id (m!c)
msgrcv - receive an ipc message (m!c)
msgsnd - send an ipc message (m!c)
munmap - unmap a file from memory (mc)
nice - change process priority (mc)
oldfstat - no longer existing
oldlstat - no longer existing
oldolduname - no longer existing
oldstat - no longer existing
olduname - no longer existing
open - open a file (m+c)
pathconf - get information about a file (m+!c)
pause - sleep until signal (m+c)
personality - change current execution domain for ibcs (-)
phys - not implemented yet (m)
pipe - create a pipe (m+c)
prof - not yet implemented ()
profil - execution time profile (m!c)
ptrace - trace a child process (mc)
quotactl - not implemented yet ()
read - read data from a file (m+c)
readv - read datablocks from a file (m!c)
readdir - read a directory (m+c)
readlink - get content of a symbolic link (mc)
reboot - reboot or toggle vulcan death grip (-mc)
recv - receive a message from a connected socket (m!c)
recvfrom - receive a message from a socket (m!c)
rename - move/rename a file (m+c)
rmdir - delete an empty directory (m+c)
sbrk - see brk (mc!)
select - sleep until action on a filedescriptor (mc)
semctl - ipc semaphore control (m!c)
semget - ipc get a semaphore set identifier (m!c)
semop - ipc operation on semaphore set members (m!c)
send - send a message to a connected socket (m!c)
sendto - send a message to a socket (m!c)
setdomainname - set system’s domainname (mc)
setfsgid - set filesystem group id ()
setfsuid - set filesystem user id ()
setgid - set real group id (m+c)
setgroups - set supplemental groups (mc)
sethostid - set unique host identifier (mc)
sethostname - set the system’s hostname (mc)
setitimer - set interval timer (mc)
setpgid - set process group id (m+c)
setpgrp - has no effect (mc!)
setpriority - set a process/group/user priority (mc)
setregid - set real and effective group id (mc)
setreuid - set real and effective user id (mc)
setrlimit - set resource limit (mc)
setsid - create a session (+c)
setsockopt - change options of a socket (mc)
settimeofday - set timezone+seconds since 1.1.1970 (mc)
setuid - set real user id (m+c)
setup - initialize devices and mount root (-)
sgetmask - see siggetmask (m)
shmat - attach shared memory to data segment (m!c)
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shmctl - ipc manipulate shared memory (m!c)
shmdt - detach shared memory from data segment (m!c)
shmget - get/create shared memory segment (m!c)
shutdown - shutdown a socket (m!c)
sigaction - set/get signal handler (m+c)
sigblock - block signals (m!c)
siggetmask - get signal blocking of current process (!c)
signal - setup a signal handler (mc)
sigpause - use a new signal mask until a signal (mc)
sigpending - get pending, but blocked signals (m+c)
sigprocmask - set/get signal blocking of current process (+c)
sigreturn - not yet used ()
sigsetmask - set signal blocking of current process (c!)
sigsuspend - replacement for sigpause (m+c)
sigvec - see sigaction (m!)
socket - create a socket communication endpoint (m!c)
socketcall - socket call multiplexer (-)
socketpair - create 2 connected sockets (m!c)
ssetmask - see sigsetmask (m)
stat - get file status (m+c)
statfs - get filesystem status (mc)
stime - set seconds since 1.1.1970 (mc)
stty - not yet implemented ()
swapoff - stop swapping to a file/device (m-c)
swapon - start swapping to a file/device (m-c)
symlink - create a symbolic link to a file (m+c)
sync - sync memory and disk buffers (mc)
syscall - execute a systemcall by number (-!c)
sysconf - get value of a system variable (m+!c)
sysfs - get infos about configured filesystems ()
sysinfo - get Linux system infos (m-)
syslog - manipulate system logging (m-c)
system - execute a shell command (m!c)
time - get seconds since 1.1.1970 (m+c)
times - get process times (m+c)
truncate - change file size (mc)
ulimit - get/set file limits (c!)
umask - set file creation mask (m+c)
umount - unmount a filesystem (mc)
uname - get system information (m+c)
unlink - remove a file when not busy (m+c)
uselib - use a shared library (m-c)
ustat - not yet implemented (c)
utime - modify inode time entries (m+c)
utimes - see utime (m!c)
vfork - see fork (m!c)
vhangup - virtually hang up current tty (m-c)
vm86 - enter virtual 8086 mode (m-c)
wait - wait for process termination (m+!c)
wait3 - bsd wait for a specified process (m!c)
wait4 - bsd wait for a specified process (mc)
waitpid - wait for a specified process (m+c)
write - write data to a file (m+c)
writev - write datablocks to a file (m!c)

(m) manual page exists.
(+) POSIX compliant.
(-) Linux specific.
(c) in libc.
(!) not a sole system call.uses a different system call.