1/* getresgid -- fetch real group ID, effective group ID, and saved-set group ID
2 Copyright (C) 2002-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#include <errno.h>
20#include <unistd.h>
21#include <hurd.h>
22#include <hurd/id.h>
23
24/* Fetch the real group ID, effective group ID, and saved-set group ID,
25 of the calling process. */
26int
27__getresgid (gid_t *rgid, gid_t *egid, gid_t *sgid)
28{
29 error_t err;
30
31retry:
32 HURD_CRITICAL_BEGIN;
33 __mutex_lock (&_hurd_id.lock);
34
35 err = _hurd_check_ids ();
36 if (!err)
37 {
38 if (_hurd_id.aux.ngids < 1)
39 /* We do not even have a real GID. */
40 err = EGRATUITOUS;
41 else
42 {
43 gid_t real = _hurd_id.aux.gids[0];
44
45 *rgid = real;
46 *egid = _hurd_id.gen.ngids < 1 ? real : _hurd_id.gen.gids[0];
47 *sgid = _hurd_id.aux.ngids < 2 ? real : _hurd_id.aux.gids[1];
48 }
49 }
50
51 __mutex_unlock (&_hurd_id.lock);
52 HURD_CRITICAL_END;
53 if (err == EINTR)
54 /* Got a signal while inside an RPC of the critical section, retry again */
55 goto retry;
56
57 return __hurd_fail (err);
58}
59libc_hidden_def (__getresgid)
60weak_alias (__getresgid, getresgid)
61

source code of glibc/sysdeps/mach/hurd/getresgid.c