1 /* $OpenBSD: res_init.c,v 1.11 2019/06/17 05:54:45 otto Exp $ */
2 /*
3 * Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
4 *
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 */
17
18 #include <sys/types.h>
19 #include <sys/socket.h>
20 #include <arpa/nameser.h>
21 #include <netinet/in.h>
22 #include <netdb.h>
23
24 #include <asr.h>
25 #include <resolv.h>
26 #include <string.h>
27
28 #include "asr_private.h"
29 #include "thread_private.h"
30
31
32 struct __res_state _res;
33 struct __res_state_ext _res_ext;
34
35 int h_errno;
36
37 int
res_init(void)38 res_init(void)
39 {
40 static void *resinit_mutex;
41 struct asr_ctx *ac;
42 int i;
43
44 ac = _asr_use_resolver(NULL);
45
46 /*
47 * The first thread to call res_init() will setup the global _res
48 * structure from the async context, not overriding fields set early
49 * by the user.
50 */
51 _MUTEX_LOCK(&resinit_mutex);
52 if (!(_res.options & RES_INIT)) {
53 if (_res.retry == 0)
54 _res.retry = ac->ac_nsretries;
55 if (_res.retrans == 0)
56 _res.retrans = ac->ac_nstimeout;
57 if (_res.options == 0)
58 _res.options = ac->ac_options;
59 if (_res.lookups[0] == '\0')
60 strlcpy(_res.lookups, ac->ac_db, sizeof(_res.lookups));
61
62 for (i = 0; i < ac->ac_nscount && i < MAXNS; i++) {
63 /*
64 * No need to check for length since we copy to a
65 * struct sockaddr_storage with a size of 256 bytes
66 * and sa_len has only 8 bits.
67 */
68 memcpy(&_res_ext.nsaddr_list[i], ac->ac_ns[i],
69 ac->ac_ns[i]->sa_len);
70 if (ac->ac_ns[i]->sa_len <= sizeof(_res.nsaddr_list[i]))
71 memcpy(&_res.nsaddr_list[i], ac->ac_ns[i],
72 ac->ac_ns[i]->sa_len);
73 else
74 memset(&_res.nsaddr_list[i], 0,
75 sizeof(_res.nsaddr_list[i]));
76 }
77 _res.nscount = i;
78 _res.options |= RES_INIT;
79 }
80 _MUTEX_UNLOCK(&resinit_mutex);
81
82 /*
83 * If the program is not threaded, we want to reflect (some) changes
84 * made by the user to the global _res structure.
85 * This is a bit of a hack: if there is already an async query on
86 * this context, it might change things in its back. It is ok
87 * as long as the user only uses the blocking resolver API.
88 * If needed we could consider cloning the context if there is
89 * a running query.
90 */
91 if (!__isthreaded) {
92 ac->ac_nsretries = _res.retry;
93 ac->ac_nstimeout = _res.retrans;
94 ac->ac_options = _res.options;
95 strlcpy(ac->ac_db, _res.lookups, sizeof(ac->ac_db));
96 ac->ac_dbcount = strlen(ac->ac_db);
97 }
98
99 _asr_ctx_unref(ac);
100
101 return (0);
102 }
103 DEF_WEAK(res_init);
104