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 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