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



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

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

       int faccessat(int dirfd, const char *pathname, 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 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 3.22 of the Linux man-pages project.  A description of the project, and informa-
       tion about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



Linux                             2008-08-21                      FACCESSAT(2)