euidaccess(3) — Linux manual page


EUIDACCESS(3)             Linux Programmer's Manual            EUIDACCESS(3)

NAME         top

       euidaccess, eaccess - check effective user's permissions for a file

SYNOPSIS         top

       #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         top

       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         top

       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.

ERRORS         top

       As for access(2).

VERSIONS         top

       The eaccess() function was added to glibc in version 2.4.

ATTRIBUTES         top

       For an explanation of the terms used in this section, see

       │Interface               Attribute     Value   │
       │euidaccess(), eaccess() │ Thread safety │ MT-Safe │

CONFORMING TO         top

       These functions are nonstandard.  Some other systems have an
       eaccess() function.

NOTES         top

       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

SEE ALSO         top

       access(2), chmod(2), chown(2), faccessat(2), open(2), setgid(2),
       setuid(2), stat(2), credentials(7), path_resolution(7)

COLOPHON         top

       This page is part of release 5.07 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at

                                 2017-09-15                    EUIDACCESS(3)

Pages that refer to this page: access(2)faccessat(2)credentials(7)