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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
   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 4.09 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/.

                              2015-03-02                     EUIDACCESS(3)



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