glibc/sysdeps/mach/hurd/getegid.c

/* Copyright (C) 1993, 1994, 1995, 1997 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <unistd.h>
#include <hurd.h>
#include <hurd/id.h>

/* Get the effective group ID of the calling process.  */
gid_t
__getegid ()
{
  error_t err;
  gid_t egid;

  HURD_CRITICAL_BEGIN;
  __mutex_lock (&_hurd_id.lock);

  if (err = _hurd_check_ids ())
    {
      errno = err;
      egid = -1;
    }
  else if (_hurd_id.gen.ngids >= 1)
    egid = _hurd_id.gen.gids[0];
  else if (_hurd_id.aux.ngids >= 1)
    /* We have no effective gids.  Return the real gid.  */
    egid = _hurd_id.aux.gids[0];
  else
    {
      /* We do not even have a real gid.  */
      errno = EGRATUITOUS;
      egid = -1;
    }

  __mutex_unlock (&_hurd_id.lock);
  HURD_CRITICAL_END;

  return egid;
}

weak_alias (__getegid, getegid)