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

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 to indicate the error.

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)

                                                                               2021-03-22                                                                  EUIDACCESS(3)