fchownat(2) - Linux man page

Name

fchownat - change ownership of a file relative to a directory file descriptor

Synopsis

#include <fcntl.h> /* Definition of AT_* constants */
#include <unistd.h>

int fchownat(int dirfd, const char *pathname,
             uid_t owner, gid_t group, int flags);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

fchownat():: Since glibc 2.10:; _XOPEN_SOURCE >= 700 || _POSIX_C_SOURCE >= 200809L; Before glibc 2.10:; _ATFILE_SOURCE

Description

The fchownat() system call operates in exactly the same way as chown(2), except for the differences described in this manual page.

If the pathname given in pathname is relative, then it is interpreted relative to the directory referred to by the file descriptor dirfd (rather than relative to the current working directory of the calling process, as is done by chown(2) for a relative pathname).

If pathname is relative and dirfd is the special value AT_FDCWD, then pathname is interpreted relative to the current working directory of the calling process (like chown(2)).

If pathname is absolute, then dirfd is ignored.

flags can either be 0, or include the following flag:

AT_SYMLINK_NOFOLLOW: If pathname is a symbolic link, do not dereference it: instead operate on the link itself, like lchown(2). (By default, fchownat() dereferences symbolic links, like chown(2).)

Return Value

On success, fchownat() returns 0. On error, -1 is returned and errno is set to indicate the error.

Errors

The same errors that occur for chown(2) can also occur for fchownat(). The following additional errors can occur for fchownat():

EBADF
dirfd is not a valid file descriptor.
EINVAL
Invalid flag specified in flags.
ENOTDIR: pathname is relative and dirfd is a file descriptor referring to a file other than a directory.

Versions

fchownat() was added to Linux in kernel 2.6.16; library support was added to glibc in version 2.4.

Conforming To

POSIX.1-2008. A similar system call exists on Solaris.

Notes

See openat(2) for an explanation of the need for fchownat().