Name
faccessat — check user's permissions of a file
relative to a directory file descriptor
Synopsis
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
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_resolution(7)
This manpage is Copyright (C) 2006, Michael Kerrisk
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