1 /*- 2 * Copyright (c) 2006 The FreeBSD Project. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #include <sys/types.h> 29 #include <sys/stat.h> 30 #include <sys/time.h> 31 #include <netinet/in.h> 32 #include <arpa/nameser.h> 33 #include <resolv.h> 34 #include <stdlib.h> 35 36 #include "namespace.h" 37 #include "reentrant.h" 38 #include "un-namespace.h" 39 40 #undef _res 41 42 struct __res_state _res; 43 44 static thread_key_t res_key; 45 static once_t res_init_once = ONCE_INITIALIZER; 46 static int res_thr_keycreated = 0; 47 48 static void 49 free_res(void *ptr) 50 { 51 res_state statp = ptr; 52 53 if (statp->_u._ext.ext != NULL) 54 res_ndestroy(statp); 55 free(statp); 56 } 57 58 static void 59 res_keycreate(void) 60 { 61 res_thr_keycreated = thr_keycreate(&res_key, free_res) == 0; 62 } 63 64 static res_state 65 res_check_reload(res_state statp) 66 { 67 struct timespec now; 68 struct stat sb; 69 70 if ((statp->options & RES_INIT) == 0 || statp->reload_period == 0) { 71 return (statp); 72 } 73 74 if (clock_gettime(CLOCK_MONOTONIC_FAST, &now) != 0 || 75 (now.tv_sec - statp->conf_stat) < statp->reload_period) { 76 return (statp); 77 } 78 79 statp->conf_stat = now.tv_sec; 80 if (stat(_PATH_RESCONF, &sb) == 0 && 81 (sb.st_mtim.tv_sec != statp->conf_mtim.tv_sec || 82 sb.st_mtim.tv_nsec != statp->conf_mtim.tv_nsec)) { 83 statp->options &= ~RES_INIT; 84 } 85 86 return (statp); 87 } 88 89 res_state 90 __res_state(void) 91 { 92 res_state statp; 93 94 if (thr_main() != 0) 95 return res_check_reload(&_res); 96 97 if (thr_once(&res_init_once, res_keycreate) != 0 || 98 !res_thr_keycreated) 99 return (&_res); 100 101 statp = thr_getspecific(res_key); 102 if (statp != NULL) 103 return res_check_reload(statp); 104 statp = calloc(1, sizeof(*statp)); 105 if (statp == NULL) 106 return (&_res); 107 #ifdef __BIND_RES_TEXT 108 statp->options = RES_TIMEOUT; /* Motorola, et al. */ 109 #endif 110 if (thr_setspecific(res_key, statp) == 0) 111 return (statp); 112 free(statp); 113 return (&_res); 114 } 115