FACCESSAT(2)                                        Linux Programmer's Manual                                       FACCESSAT(2)



NAME
       faccessat - check user's permissions of a file relative to a directory file descriptor

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

       int faccessat(int dirfd, const char *pathname, int mode, int flags);

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

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

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 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 access(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 access(2)).

       If pathname 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 real IDs (like
              access(2)).

       AT_SYMLINK_NOFOLLOW
              If pathname is a symbolic link, do not dereference it: instead return information about the link itself.

RETURN VALUE
       On success, (all requested permissions granted) 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 faccessat().  The following additional errors can occur for
       faccessat():

       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
       faccessat() was added to Linux in kernel 2.6.16.

CONFORMING TO
       POSIX.1-2008.

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

   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.

SEE ALSO
       access(2), openat(2), euidaccess(3), credentials(7), path_resolution(7), symlink(7)

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                                                      2009-12-13                                               FACCESSAT(2)