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 * $FreeBSD$ 28 */ 29 30 #include <sys/types.h> 31 #include <sys/stat.h> 32 #include <sys/time.h> 33 #include <netinet/in.h> 34 #include <arpa/nameser.h> 35 #include <resolv.h> 36 #include <stdlib.h> 37 38 #include "namespace.h" 39 #include "reentrant.h" 40 #include "un-namespace.h" 41 42 #include "res_private.h" 43 44 #undef _res 45 46 struct __res_state _res; 47 48 static thread_key_t res_key; 49 static once_t res_init_once = ONCE_INITIALIZER; 50 static int res_thr_keycreated = 0; 51 52 static void 53 free_res(void *ptr) 54 { 55 res_state statp = ptr; 56 57 if (statp->_u._ext.ext != NULL) 58 res_ndestroy(statp); 59 free(statp); 60 } 61 62 static void 63 res_keycreate(void) 64 { 65 res_thr_keycreated = thr_keycreate(&res_key, free_res) == 0; 66 } 67 68 static res_state 69 res_check_reload(res_state statp) 70 { 71 struct timespec now; 72 struct stat sb; 73 struct __res_state_ext *ext; 74 75 if ((statp->options & RES_INIT) == 0) { 76 return (statp); 77 } 78 79 ext = statp->_u._ext.ext; 80 if (ext == NULL || ext->reload_period == 0) { 81 return (statp); 82 } 83 84 if (clock_gettime(CLOCK_MONOTONIC_FAST, &now) != 0 || 85 (now.tv_sec - ext->conf_stat) < ext->reload_period) { 86 return (statp); 87 } 88 89 ext->conf_stat = now.tv_sec; 90 if (stat(_PATH_RESCONF, &sb) == 0 && 91 (sb.st_mtim.tv_sec != ext->conf_mtim.tv_sec || 92 sb.st_mtim.tv_nsec != ext->conf_mtim.tv_nsec)) { 93 statp->options &= ~RES_INIT; 94 } 95 96 return (statp); 97 } 98 99 res_state 100 __res_state(void) 101 { 102 res_state statp; 103 104 if (thr_main() != 0) 105 return res_check_reload(&_res); 106 107 if (thr_once(&res_init_once, res_keycreate) != 0 || 108 !res_thr_keycreated) 109 return (&_res); 110 111 statp = thr_getspecific(res_key); 112 if (statp != NULL) 113 return res_check_reload(statp); 114 statp = calloc(1, sizeof(*statp)); 115 if (statp == NULL) 116 return (&_res); 117 #ifdef __BIND_RES_TEXT 118 statp->options = RES_TIMEOUT; /* Motorola, et al. */ 119 #endif 120 if (thr_setspecific(res_key, statp) == 0) 121 return (statp); 122 free(statp); 123 return (&_res); 124 } 125