1/* Copyright (C) 1993-2022 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <sys/types.h>
20#include <unistd.h>
21#include <hurd.h>
22#include <hurd/id.h>
23#include <string.h>
24
25int
26__setregid (gid_t rgid, gid_t egid)
27{
28 auth_t newauth;
29 error_t err;
30
31retry:
32 HURD_CRITICAL_BEGIN;
33 __mutex_lock (&_hurd_id.lock);
34 err = _hurd_check_ids ();
35
36 if (!err)
37 {
38 /* Make a new auth handle which has RGID as the real gid,
39 and EGID as the first element in the list of effective gids. */
40
41 gid_t *newgen, *newaux;
42 size_t ngen, naux;
43
44 newgen = _hurd_id.gen.gids;
45 ngen = _hurd_id.gen.ngids;
46 if (egid != -1)
47 {
48 if (_hurd_id.gen.ngids == 0)
49 {
50 /* No effective gids now. The new set will be just GID. */
51 newgen = &egid;
52 ngen = 1;
53 }
54 else
55 {
56 _hurd_id.gen.gids[0] = egid;
57 _hurd_id.valid = 0;
58 }
59 }
60
61 newaux = _hurd_id.aux.gids;
62 naux = _hurd_id.aux.ngids;
63 if (rgid != -1)
64 {
65 if (_hurd_id.aux.ngids == 0)
66 {
67 newaux = &rgid;
68 naux = 1;
69 }
70 else
71 {
72 _hurd_id.aux.gids[0] = rgid;
73 _hurd_id.valid = 0;
74 }
75 }
76
77 err = __USEPORT (AUTH, __auth_makeauth
78 (port, NULL, MACH_MSG_TYPE_COPY_SEND, 0,
79 _hurd_id.gen.uids, _hurd_id.gen.nuids,
80 _hurd_id.aux.uids, _hurd_id.aux.nuids,
81 newgen, ngen, newaux, naux,
82 &newauth));
83 }
84 __mutex_unlock (&_hurd_id.lock);
85 HURD_CRITICAL_END;
86 if (err == EINTR)
87 /* Got a signal while inside an RPC of the critical section, retry again */
88 goto retry;
89
90 if (err)
91 return __hurd_fail (err);
92
93 /* Install the new handle and reauthenticate everything. */
94 err = __setauth (newauth);
95 __mach_port_deallocate (__mach_task_self (), newauth);
96 return err;
97}
98
99weak_alias (__setregid, setregid)
100

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