1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2006 The FreeBSD Project. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 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 #include "res_private.h" 41 42 #undef _res 43 44 struct __res_state _res; 45 46 static thread_key_t res_key; 47 static once_t res_init_once = ONCE_INITIALIZER; 48 static int res_thr_keycreated = 0; 49 50 static void 51 free_res(void *ptr) 52 { 53 res_state statp = ptr; 54 55 if (statp->_u._ext.ext != NULL) 56 res_ndestroy(statp); 57 free(statp); 58 } 59 60 static void 61 res_keycreate(void) 62 { 63 res_thr_keycreated = thr_keycreate(&res_key, free_res) == 0; 64 } 65 66 static res_state 67 res_check_reload(res_state statp) 68 { 69 struct timespec now; 70 struct stat sb; 71 struct __res_state_ext *ext; 72 73 if ((statp->options & RES_INIT) == 0) { 74 return (statp); 75 } 76 77 ext = statp->_u._ext.ext; 78 if (ext == NULL || ext->reload_period == 0) { 79 return (statp); 80 } 81 82 if (clock_gettime(CLOCK_MONOTONIC_FAST, &now) != 0 || 83 (now.tv_sec - ext->conf_stat) < ext->reload_period) { 84 return (statp); 85 } 86 87 ext->conf_stat = now.tv_sec; 88 if (stat(_PATH_RESCONF, &sb) == 0 && 89 (sb.st_mtim.tv_sec != ext->conf_mtim.tv_sec || 90 sb.st_mtim.tv_nsec != ext->conf_mtim.tv_nsec)) { 91 statp->options &= ~RES_INIT; 92 } 93 94 return (statp); 95 } 96 97 res_state 98 __res_state(void) 99 { 100 res_state statp; 101 102 if (thr_main() != 0) 103 return res_check_reload(&_res); 104 105 if (thr_once(&res_init_once, res_keycreate) != 0 || 106 !res_thr_keycreated) 107 return (&_res); 108 109 statp = thr_getspecific(res_key); 110 if (statp != NULL) 111 return res_check_reload(statp); 112 statp = calloc(1, sizeof(*statp)); 113 if (statp == NULL) 114 return (&_res); 115 #ifdef __BIND_RES_TEXT 116 statp->options = RES_TIMEOUT; /* Motorola, et al. */ 117 #endif 118 if (thr_setspecific(res_key, statp) == 0) 119 return (statp); 120 free(statp); 121 return (&_res); 122 } 123