Section 2: system calls
NAME link, linkat – make a new name for a file SYNOPSIS #include <unistd.h> int link(const char *oldpath, const char *newpath); #include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h> int linkat(int olddirfd, const char *oldpath, int newdirfd, const char *newpath, int flags); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): linkat(): Since glibc…
NAME link, linkat – make a new name for a file SYNOPSIS #include <unistd.h> int link(const char *oldpath, const char *newpath); #include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h> int linkat(int olddirfd, const char *oldpath, int newdirfd, const char *newpath, int flags); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): linkat(): Since glibc…
NAME getxattr, lgetxattr, fgetxattr – retrieve an extended attribute value SYNOPSIS #include <sys/types.h> #include <sys/xattr.h> ssize_t getxattr(const char *path, const char *name, void *value, size_t size); ssize_t lgetxattr(const char *path, const char *name, void *value, size_t size); ssize_t fgetxattr(int fd, const char *name, void *value, size_t size);…
NAME chown, fchown, lchown, fchownat – change ownership of a file SYNOPSIS #include <unistd.h> int chown(const char *pathname, uid_t owner, gid_t group); int fchown(int fd, uid_t owner, gid_t group); int lchown(const char *pathname, uid_t owner, gid_t group); #include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h> int fchownat(int dirfd, const char *pathname, uid_t owner,…
NAME chown, fchown, lchown, fchownat – change ownership of a file SYNOPSIS #include <unistd.h> int chown(const char *pathname, uid_t owner, gid_t group); int fchown(int fd, uid_t owner, gid_t group); int lchown(const char *pathname, uid_t owner, gid_t group); #include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h> int fchownat(int dirfd, const char *pathname, uid_t owner,…
NAME killpg – send signal to a process group SYNOPSIS #include <signal.h> int killpg(int pgrp, int sig); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): killpg(): _XOPEN_SOURCE >= 500 || /* Since glibc 2.19: */ _DEFAULT_SOURCE || /* Glibc versions <= 2.19: */ _BSD_SOURCE DESCRIPTION killpg() sends the signal sig to the process group pgrp. See signal(7) for a list of signals. If pgrp is 0, killpg()…
NAME kill – send signal to a process SYNOPSIS #include <signal.h> #include <sys/types.h> int kill(pid_t pid, int sig); Feature Test Macro Requirements for glibc (see feature_test_macros(7)): kill(): _POSIX_C_SOURCE DESCRIPTION The kill() system call can be used to send any signal to any process group or process. If pid is positive, then signal sig is sent…
NAME keyctl – manipulate the kernel’s key management facility SYNOPSIS #include <keyutils.h> #include <sys/types.h> long keyctl(int operation, …); /* For direct call via syscall(2): */ #include <asm/unistd.h> #include <linux/keyctl.h> #include <unistd.h> long syscall(__NR_keyctl, int operation, __kernel_ulong_t arg2, __kernel_ulong_t arg3, __kernel_ulong_t arg4, __kernel_ulong_t arg5); No glibc wrapper is provided for this system call; see NOTES. DESCRIPTION…
NAME kexec_load, kexec_file_load – load a new kernel for later execution SYNOPSIS #include <linux/kexec.h> long kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment *segments, unsigned long flags); long kexec_file_load(int kernel_fd, int initrd_fd, unsigned long cmdline_len, const char *cmdline, unsigned long flags); Note: There are no glibc wrappers for these system calls; see NOTES. DESCRIPTION The…
NAME kexec_load, kexec_file_load – load a new kernel for later execution SYNOPSIS #include <linux/kexec.h> long kexec_load(unsigned long entry, unsigned long nr_segments, struct kexec_segment *segments, unsigned long flags); long kexec_file_load(int kernel_fd, int initrd_fd, unsigned long cmdline_len, const char *cmdline, unsigned long flags); Note: There are no glibc wrappers for these system calls; see NOTES. DESCRIPTION The…
NAME kcmp – compare two processes to determine if they share a kernel resource SYNOPSIS #include <linux/kcmp.h> int kcmp(pid_t pid1, pid_t pid2, int type, unsigned long idx1, unsigned long idx2); Note: There is no glibc wrapper for this system call; see NOTES. DESCRIPTION The kcmp() system call can be used to check whether the two…
NAME afs_syscall, break, fattach, fdetach, ftime, getmsg, getpmsg, gtty, isastream, lock, madvise1, mpx, prof, profil, putmsg, putpmsg, security, stty, tuxcall, ulimit, vserver – unimplemented system calls SYNOPSIS Unimplemented system calls. DESCRIPTION These system calls are not implemented in the Linux kernel. RETURN VALUE These system calls always return -1 and set errno to ENOSYS. NOTES…
NAME ipc – System V IPC system calls SYNOPSIS int ipc(unsigned int call, int first, int second, int third, void *ptr, long fifth); DESCRIPTION ipc() is a common kernel entry point for the System V IPC calls for messages, semaphores, and shared memory. call determines which IPC function to invoke; the other arguments are passed…
NAME ioprio_get, ioprio_set – get/set I/O scheduling class and priority SYNOPSIS int ioprio_get(int which, int who); int ioprio_set(int which, int who, int ioprio); Note: There are no glibc wrappers for these system calls; see NOTES. DESCRIPTION The ioprio_get() and ioprio_set() system calls get and set the I/O scheduling class and priority of one or more…
NAME ioprio_get, ioprio_set – get/set I/O scheduling class and priority SYNOPSIS int ioprio_get(int which, int who); int ioprio_set(int which, int who, int ioprio); Note: There are no glibc wrappers for these system calls; see NOTES. DESCRIPTION The ioprio_get() and ioprio_set() system calls get and set the I/O scheduling class and priority of one or more…
NAME iopl – change I/O privilege level SYNOPSIS #include <sys/io.h> int iopl(int level); DESCRIPTION iopl() changes the I/O privilege level of the calling thread, as specified by the two least significant bits in level. The I/O privilege level for a normal thread is 0. Permissions are inherited from parents to children. This call is deprecated,…
NAME ioperm – set port input/output permissions SYNOPSIS #include <sys/io.h> /* for glibc */ int ioperm(unsigned long from, unsigned long num, int turn_on); DESCRIPTION ioperm() sets the port access permission bits for the calling thread for num bits starting from port address from. If turn_on is nonzero, then permission for the specified bits is enabled;…
NAME ioctl_userfaultfd – create a file descriptor for handling page faults in user space SYNOPSIS #include <sys/ioctl.h> int ioctl(int fd, int cmd, …); DESCRIPTION Various ioctl(2) operations can be performed on a userfaultfd object (created by a call to userfaultfd(2)) using calls of the form: ioctl(fd, cmd, argp); In the above, fd is a file…
NAME ioctl_tty – ioctls for terminals and serial lines SYNOPSIS #include <termios.h> int ioctl(int fd, int cmd, …); DESCRIPTION The ioctl(2) call for terminals and serial ports accepts many possible command arguments. Most require a third argument, of varying type, here called argp or arg. Use of ioctl makes for nonportable programs. Use the POSIX…
NAME ioctl_ns – ioctl() operations for Linux namespaces DESCRIPTION Discovering namespace relationships The following ioctl(2) operations are provided to allow discovery of namespace relationships (see user_namespaces(7) and pid_namespaces(7)). The form of the calls is: new_fd = ioctl(fd, request); In each case, fd refers to a /proc/[pid]/ns/* file. Both operations return a new file descriptor on…