1 /* 2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org> 3 * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org> 4 * 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. Neither the name of the author nor the names of any co-contributors 12 * may be used to endorse or promote products derived from this software 13 * without specific prior written permission. 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 /* 31 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 32 * All rights reserved. 33 * 34 * Redistribution and use in source and binary forms, with or without 35 * modification, are permitted provided that the following conditions 36 * are met: 37 * 1. Redistributions of source code must retain the above copyright 38 * notice, this list of conditions and the following disclaimer. 39 * 2. Redistributions in binary form must reproduce the above copyright 40 * notice, this list of conditions and the following disclaimer in the 41 * documentation and/or other materials provided with the distribution. 42 * 3. Neither the name of the author nor the names of any co-contributors 43 * may be used to endorse or promote products derived from this software 44 * without specific prior written permission. 45 * 46 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 47 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 48 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 49 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 50 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 51 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 52 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 53 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 54 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 55 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 56 * SUCH DAMAGE. 57 * 58 */ 59 60 #include "namespace.h" 61 #include <errno.h> 62 #include <link.h> 63 #include <string.h> 64 #include <stdlib.h> 65 #include <unistd.h> 66 #include <pthread.h> 67 #include <spinlock.h> 68 #include "un-namespace.h" 69 70 #include "libc_private.h" 71 #include "rtld_lock.h" 72 #include "thr_private.h" 73 74 __weak_reference(_pthread_atfork, pthread_atfork); 75 76 int 77 _pthread_atfork(void (*prepare)(void), void (*parent)(void), 78 void (*child)(void)) 79 { 80 struct pthread *curthread; 81 struct pthread_atfork *af; 82 83 _thr_check_init(); 84 85 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 86 return (ENOMEM); 87 88 curthread = _get_curthread(); 89 af->prepare = prepare; 90 af->parent = parent; 91 af->child = child; 92 THR_CRITICAL_ENTER(curthread); 93 _thr_rwl_wrlock(&_thr_atfork_lock); 94 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 95 _thr_rwl_unlock(&_thr_atfork_lock); 96 THR_CRITICAL_LEAVE(curthread); 97 return (0); 98 } 99 100 void 101 __pthread_cxa_finalize(struct dl_phdr_info *phdr_info) 102 { 103 atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list); 104 struct pthread *curthread; 105 struct pthread_atfork *af, *af1; 106 107 _thr_check_init(); 108 109 curthread = _get_curthread(); 110 THR_CRITICAL_ENTER(curthread); 111 _thr_rwl_wrlock(&_thr_atfork_lock); 112 TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) { 113 if (__elf_phdr_match_addr(phdr_info, af->prepare) || 114 __elf_phdr_match_addr(phdr_info, af->parent) || 115 __elf_phdr_match_addr(phdr_info, af->child)) { 116 TAILQ_REMOVE(&_thr_atfork_list, af, qe); 117 TAILQ_INSERT_TAIL(&temp_list, af, qe); 118 } 119 } 120 _thr_rwl_unlock(&_thr_atfork_lock); 121 THR_CRITICAL_LEAVE(curthread); 122 while ((af = TAILQ_FIRST(&temp_list)) != NULL) { 123 TAILQ_REMOVE(&temp_list, af, qe); 124 free(af); 125 } 126 _thr_tsd_unload(phdr_info); 127 _thr_sigact_unload(phdr_info); 128 } 129 130 __weak_reference(_fork, fork); 131 132 pid_t _fork(void); 133 134 pid_t 135 _fork(void) 136 { 137 struct pthread *curthread; 138 struct pthread_atfork *af; 139 pid_t ret; 140 int errsave, cancelsave; 141 int was_threaded; 142 int rtld_locks[MAX_RTLD_LOCKS]; 143 144 if (!_thr_is_inited()) 145 return (__sys_fork()); 146 147 curthread = _get_curthread(); 148 cancelsave = curthread->no_cancel; 149 curthread->no_cancel = 1; 150 _thr_rwl_rdlock(&_thr_atfork_lock); 151 152 /* Run down atfork prepare handlers. */ 153 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { 154 if (af->prepare != NULL) 155 af->prepare(); 156 } 157 158 /* 159 * Block all signals until we reach a safe point. 160 */ 161 _thr_signal_block(curthread); 162 _thr_signal_prefork(); 163 164 /* 165 * All bets are off as to what should happen soon if the parent 166 * process was not so kindly as to set up pthread fork hooks to 167 * relinquish all running threads. 168 */ 169 if (_thr_isthreaded() != 0) { 170 was_threaded = 1; 171 _malloc_prefork(); 172 _rtld_atfork_pre(rtld_locks); 173 } else { 174 was_threaded = 0; 175 } 176 177 /* Fork a new process: */ 178 if ((ret = __sys_fork()) == 0) { 179 /* Child process */ 180 errsave = errno; 181 curthread->cancel_pending = 0; 182 curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED); 183 184 /* 185 * Thread list will be reinitialized, and later we call 186 * _libpthread_init(), it will add us back to list. 187 */ 188 curthread->tlflags &= ~TLFLAGS_IN_TDLIST; 189 190 /* child is a new kernel thread. */ 191 thr_self(&curthread->tid); 192 193 /* clear other threads locked us. */ 194 _thr_umutex_init(&curthread->lock); 195 _mutex_fork(curthread); 196 197 _thr_signal_postfork_child(); 198 199 if (was_threaded) 200 _rtld_atfork_post(rtld_locks); 201 _thr_setthreaded(0); 202 203 /* reinitialize libc spinlocks. */ 204 _thr_spinlock_init(); 205 206 /* reinitalize library. */ 207 _libpthread_init(curthread); 208 209 /* atfork is reinitializeded by _libpthread_init()! */ 210 _thr_rwl_rdlock(&_thr_atfork_lock); 211 212 if (was_threaded) { 213 __isthreaded = 1; 214 _malloc_postfork(); 215 __isthreaded = 0; 216 } 217 218 /* Ready to continue, unblock signals. */ 219 _thr_signal_unblock(curthread); 220 221 /* Run down atfork child handlers. */ 222 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 223 if (af->child != NULL) 224 af->child(); 225 } 226 _thr_rwlock_unlock(&_thr_atfork_lock); 227 curthread->no_cancel = cancelsave; 228 } else { 229 /* Parent process */ 230 errsave = errno; 231 232 _thr_signal_postfork(); 233 234 if (was_threaded) { 235 _rtld_atfork_post(rtld_locks); 236 _malloc_postfork(); 237 } 238 239 /* Ready to continue, unblock signals. */ 240 _thr_signal_unblock(curthread); 241 242 /* Run down atfork parent handlers. */ 243 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 244 if (af->parent != NULL) 245 af->parent(); 246 } 247 248 _thr_rwlock_unlock(&_thr_atfork_lock); 249 curthread->no_cancel = cancelsave; 250 /* test async cancel */ 251 if (curthread->cancel_async) 252 _thr_testcancel(curthread); 253 } 254 errno = errsave; 255 256 /* Return the process ID: */ 257 return (ret); 258 } 259