FACCESSAT(2) Linux Programmer's Manual FACCESSAT(2)NAMEfaccessat - change permissions of a file relative to a directory file
descriptor
SYNOPSIS
#include <unistd.h>
int faccessat(int dirfd, const char *path, int mode, int flags);
DESCRIPTION
The faccessat() system call operates in exactly the same way as
access(2), except for the differences described in this manual page.
If the pathname given in path is relative, then it is interpreted rela‐
tive 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 access(2) for a relative pathname).
If the pathname given in path is relative and dirfd is the special
value AT_FDCWD, then path is interpreted relative to the current work‐
ing directory of the calling process (like access(2)).
If the pathname given in path is absolute, then dirfd is ignored.
flags is constructed by ORing together zero or more of the following
values:
AT_EACCESS
Perform access checks using the effective user and group IDs.
By default, faccessat() uses the effective IDs (like access(2)).
AT_SYMLINK_NOFOLLOW
If path is a symbolic link, do not dereference it: instead
return information about the link itself.
RETURN VALUE
On success, faccessat() returns 0. On error, -1 is returned and errno
is set to indicate the error.
ERRORS
The same errors that occur for access(2) can also occur for facces‐
sat(). The following additional errors can occur for faccessat():
EBADF dirfd is not a valid file descriptor.
EINVAL Invalid flag specified in flags.
ENOTDIR
path is a relative path and dirfd is a file descriptor referring
to a file other than a directory.
NOTES
See openat(2) for an explanation of the need for faccessat().
CONFORMING TO
This system call is non-standard but is proposed for inclusion in a
future revision of POSIX.1.
GLIBC NOTES
The AT_EACCESS and AT_SYMLINK_NOFOLLOW flags are actually implemented
within the glibc wrapper function for faccessat(). If either of these
flags are specified, then the wrapper function employs fstatat(2) to
determine access permissions.
VERSIONSfaccessat() was added to Linux in kernel 2.6.16.
SEE ALSOaccess(2), openat(2), path_resolution(2)Linux 2.6.16 2006-05-05 FACCESSAT(2)
