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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 <&lt;fcntl.h>&gt; /* Definition of AT_* constants */
       #include <&lt;unistd.h>&gt;

       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  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.

CONFORMING TO
       This system call is non-standard but is proposed  for  inclusion  in  a
       future revision of POSIX.1.

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_resolu-
       tion(7), symlink(7)

COLOPHON
       This  page  is  part of release 3.05 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                             2007-02-28                      FACCESSAT(2)