1 /* $OpenBSD: res_init.c,v 1.2 2013/05/27 17:31:01 eric 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 41 ac = asr_use_resolver(NULL); 42 43 /* 44 * The first thread to call res_init() will setup the global _res 45 * structure from the async context, not overriding fields set early 46 * by the user. 47 */ 48 _THREAD_PRIVATE_MUTEX_LOCK(init); 49 if (!(_res.options & RES_INIT)) { 50 if (_res.retry == 0) 51 _res.retry = ac->ac_nsretries; 52 if (_res.options == 0) 53 _res.options = ac->ac_options; 54 if (_res.lookups[0] == '\0') 55 strlcpy(_res.lookups, ac->ac_db, sizeof(_res.lookups)); 56 57 _res.nscount = ac->ac_nscount; 58 _res.options |= RES_INIT; 59 } 60 _THREAD_PRIVATE_MUTEX_UNLOCK(init); 61 62 /* 63 * If the program is not threaded, we want to reflect (some) changes 64 * made by the user to the global _res structure. 65 * This is a bit of a hack: if there is already an async query on 66 * this context, it might change things in its back. It is ok 67 * as long as the user only uses the blocking resolver API. 68 * If needed we could consider cloning the context if there is 69 * a running query. 70 */ 71 if (!__isthreaded) { 72 ac->ac_nsretries = _res.retry; 73 ac->ac_options = _res.options; 74 strlcpy(ac->ac_db, _res.lookups, sizeof(ac->ac_db)); 75 ac->ac_dbcount = strlen(ac->ac_db); 76 } 77 78 asr_ctx_unref(ac); 79 80 return (0); 81 } 82