glibc/sysdeps/mach/hurd/getgid.c

/* Copyright (C) 1993-2023 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

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

/* Get the real group ID of the calling process.  */
gid_t
__getgid (void)
{
  error_t err;
  gid_t gid;

retry:
  HURD_CRITICAL_BEGIN;
  __mutex_lock (&_hurd_id.lock);

  if (err = _hurd_check_ids ())
    gid = __hurd_fail (err);
  else if (_hurd_id.aux.ngids >= 1)
    gid = _hurd_id.aux.gids[0];
  else
    /* We do not even have a real gid.  */
    gid = __hurd_fail (EGRATUITOUS);

  __mutex_unlock (&_hurd_id.lock);
  HURD_CRITICAL_END;
  if (gid == -1 && errno == EINTR)
    /* Got a signal while inside an RPC of the critical section, retry again */
    goto retry;

  return gid;
}

weak_alias (__getgid, getgid)