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EUIDACCESS(3) Linux Programmer's Manual EUIDACCESS(3)
euidaccess, eaccess - check effective user's permissions for a file
#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);
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.
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.
As for access(2).
The eaccess() function was added to glibc in version 2.4.
These functions are nonstandard. Some other systems have an eaccess()
function.
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.
access(2), chmod(2), chown(2), faccessat(2), open(2), setgid(2), setuid(2),
stat(2), credentials(7), path_resolution(7)
This page is part of release 3.32 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/.
2010-11-01 EUIDACCESS(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface