1/* Miscellaneous definitions for libresolv.
2 Copyright (C) 1995-2023 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/*
20 * Copyright (c) 1995-1999 by Internet Software Consortium.
21 *
22 * Permission to use, copy, modify, and distribute this software for any
23 * purpose with or without fee is hereby granted, provided that the above
24 * copyright notice and this permission notice appear in all copies.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
27 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
28 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
29 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
30 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
31 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
32 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
33 * SOFTWARE.
34 */
35
36#include <resolv.h>
37
38/* This function belongs to libresolv, which is why it is not included
39 in res-close.c. */
40void
41__res_close (void)
42{
43 /* Some programs call res_close before res_init. Since _res._vcsock
44 isn't explicitly initialized, these means that we could call
45 close (0), which might lead to some security problems. Therefore
46 we check if res_init was called before by looking at the RES_INIT
47 bit in _res.options. If it hasn't been set we bail out
48 early. */
49 if ((_res.options & RES_INIT) == 0)
50 return;
51 /* We don't free the name server addresses because we never did it
52 and it would be done implicitly on shutdown. */
53 __res_iclose (&_res, false);
54}
55