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.

ERRORS

       As for access(2).

VERSIONS

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

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌────────────────────────┬───────────────┬─────────┐
       │Interface               │ Attribute     │ Value   │
       ├────────────────────────┼───────────────┼─────────┤
       │euidaccess(), eaccess() │ Thread safety │ MT-Safe │
       └────────────────────────┴───────────────┴─────────┘

CONFORMING TO

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

NOTES

       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 4.15 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 https://www.kernel.org/doc/man-pages/.

                                            2017-09-15                              EUIDACCESS(3)