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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
       #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  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
              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;  library  support  was
       added to glibc in version 2.4.
CONFORMING TO
       POSIX.1-2008.
NOTES
       See openat(2) for an explanation of the need for faccessat().
       Warning: faccessat() is subject to the same kinds of races as access(2)
       and euidaccess(3).
   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_resolu-
       tion(7), symlink(7)
COLOPHON
       This page is part of release 3.53 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                             2012-05-04                      FACCESSAT(2)