Name
euidaccess, eaccess — check effective user's permissions for a file
Synopsis
#define _GNU_SOURCE /* See feature_test_macros(7) */ #include <unistd.h>
int
euidaccess( |
const char *pathname, |
int mode); |
int
eaccess( |
const char *pathname, |
int mode); |
DESCRIPTION
Like access(2), euidaccess() checks permissions and
existence of the file identified by its argument pathname. However, whereas
access(2), performs checks
using the real user and group identifiers of the process,
euidaccess() uses the effective
identifiers.
mode is a mask
consisting of one or more of R_OK, W_OK,
X_OK and F_OK, with the same meanings as for
access(2).
eaccess() is a synonym for
euidaccess(), provided for
compatibility with some other systems.
RETURN VALUE
On success (all requested permissions granted), zero is
returned. On error (at least one bit in mode asked for a permission
that is denied, or some other error occurred), −1 is
returned, and errno is set
appropriately.
NOTES
![[Warning]](../stylesheet/warning.png) |
Warning |
|---|---|
|
Using this function to check a process's permissions on a file before performing some operation based on that information leads to race conditions: the file permissions may change between the two steps. Generally, it is safer just to attempt the desired operation and handle any permission error that occurs. |
This function always dereferences symbolic links. If you
need to check the permissions on a symbolic link, use
faccessat(2) with the flags
AT_EACCESS and AT_SYMLINK_NOFOLLOW.
SEE ALSO
access(2), chmod(2), chown(2), faccessat(2), open(2), setgid(2), setuid(2), stat(2), credentials(7), path_resolution(7)
COLOPHON
This page is part of release 3.52 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/.
|
Copyright (C) 2007 Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END |