1 /* $OpenBSD: res_init.c,v 1.3 2014/01/15 02:25:34 sthen 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 <arpa/nameser.h> 20 #include <netinet/in.h> 21 22 #include <resolv.h> 23 #include <string.h> 24 25 #include "asr.h" 26 #include "asr_private.h" 27 #include "thread_private.h" 28 29 30 struct __res_state _res; 31 struct __res_state_ext _res_ext; 32 33 int h_errno; 34 35 int 36 res_init(void) 37 { 38 _THREAD_PRIVATE_MUTEX(init); 39 struct asr_ctx *ac; 40 int i; 41 42 ac = asr_use_resolver(NULL); 43 44 /* 45 * The first thread to call res_init() will setup the global _res 46 * structure from the async context, not overriding fields set early 47 * by the user. 48 */ 49 _THREAD_PRIVATE_MUTEX_LOCK(init); 50 if (!(_res.options & RES_INIT)) { 51 if (_res.retry == 0) 52 _res.retry = ac->ac_nsretries; 53 if (_res.options == 0) 54 _res.options = ac->ac_options; 55 if (_res.lookups[0] == '\0') 56 strlcpy(_res.lookups, ac->ac_db, sizeof(_res.lookups)); 57 58 _res.nscount = ac->ac_nscount; 59 for (i = 0; i < ac->ac_nscount; i++) { 60 memcpy(&_res.nsaddr_list[i], ac->ac_ns[i], 61 ac->ac_ns[i]->sa_len); 62 } 63 _res.options |= RES_INIT; 64 } 65 _THREAD_PRIVATE_MUTEX_UNLOCK(init); 66 67 /* 68 * If the program is not threaded, we want to reflect (some) changes 69 * made by the user to the global _res structure. 70 * This is a bit of a hack: if there is already an async query on 71 * this context, it might change things in its back. It is ok 72 * as long as the user only uses the blocking resolver API. 73 * If needed we could consider cloning the context if there is 74 * a running query. 75 */ 76 if (!__isthreaded) { 77 ac->ac_nsretries = _res.retry; 78 ac->ac_options = _res.options; 79 strlcpy(ac->ac_db, _res.lookups, sizeof(ac->ac_db)); 80 ac->ac_dbcount = strlen(ac->ac_db); 81 } 82 83 asr_ctx_unref(ac); 84 85 return (0); 86 } 87