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 <sys/syscall.h> 61 #include "namespace.h" 62 #include <errno.h> 63 #include <link.h> 64 #include <string.h> 65 #include <stdlib.h> 66 #include <unistd.h> 67 #include <pthread.h> 68 #include <spinlock.h> 69 #include "un-namespace.h" 70 71 #include "libc_private.h" 72 #include "rtld_lock.h" 73 #include "thr_private.h" 74 75 __weak_reference(_pthread_atfork, pthread_atfork); 76 77 int 78 _pthread_atfork(void (*prepare)(void), void (*parent)(void), 79 void (*child)(void)) 80 { 81 struct pthread *curthread; 82 struct pthread_atfork *af; 83 84 _thr_check_init(); 85 86 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 87 return (ENOMEM); 88 89 curthread = _get_curthread(); 90 af->prepare = prepare; 91 af->parent = parent; 92 af->child = child; 93 THR_CRITICAL_ENTER(curthread); 94 _thr_rwl_wrlock(&_thr_atfork_lock); 95 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 96 _thr_rwl_unlock(&_thr_atfork_lock); 97 THR_CRITICAL_LEAVE(curthread); 98 return (0); 99 } 100 101 void 102 __pthread_cxa_finalize(struct dl_phdr_info *phdr_info) 103 { 104 atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list); 105 struct pthread *curthread; 106 struct pthread_atfork *af, *af1; 107 108 _thr_check_init(); 109 110 curthread = _get_curthread(); 111 THR_CRITICAL_ENTER(curthread); 112 _thr_rwl_wrlock(&_thr_atfork_lock); 113 TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) { 114 if (__elf_phdr_match_addr(phdr_info, af->prepare) || 115 __elf_phdr_match_addr(phdr_info, af->parent) || 116 __elf_phdr_match_addr(phdr_info, af->child)) { 117 TAILQ_REMOVE(&_thr_atfork_list, af, qe); 118 TAILQ_INSERT_TAIL(&temp_list, af, qe); 119 } 120 } 121 _thr_rwl_unlock(&_thr_atfork_lock); 122 THR_CRITICAL_LEAVE(curthread); 123 while ((af = TAILQ_FIRST(&temp_list)) != NULL) { 124 TAILQ_REMOVE(&temp_list, af, qe); 125 free(af); 126 } 127 _thr_tsd_unload(phdr_info); 128 _thr_sigact_unload(phdr_info); 129 } 130 131 __weak_reference(__thr_fork, _fork); 132 133 pid_t 134 __thr_fork(void) 135 { 136 struct pthread *curthread; 137 struct pthread_atfork *af; 138 pid_t ret; 139 int errsave, cancelsave; 140 int was_threaded; 141 int rtld_locks[MAX_RTLD_LOCKS]; 142 143 if (!_thr_is_inited()) 144 return (__sys_fork()); 145 146 curthread = _get_curthread(); 147 cancelsave = curthread->no_cancel; 148 curthread->no_cancel = 1; 149 _thr_rwl_rdlock(&_thr_atfork_lock); 150 151 /* Run down atfork prepare handlers. */ 152 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { 153 if (af->prepare != NULL) 154 af->prepare(); 155 } 156 157 /* 158 * Block all signals until we reach a safe point. 159 */ 160 _thr_signal_block(curthread); 161 _thr_signal_prefork(); 162 163 /* 164 * All bets are off as to what should happen soon if the parent 165 * process was not so kindly as to set up pthread fork hooks to 166 * relinquish all running threads. 167 */ 168 if (_thr_isthreaded() != 0) { 169 was_threaded = 1; 170 _malloc_prefork(); 171 _rtld_atfork_pre(rtld_locks); 172 } else { 173 was_threaded = 0; 174 } 175 176 /* 177 * Fork a new process. 178 * There is no easy way to pre-resolve the __sys_fork symbol 179 * without performing the fork. Use the syscall(2) 180 * indirection, the syscall symbol is resolved in 181 * _thr_rtld_init() with side-effect free call. 182 */ 183 ret = syscall(SYS_fork); 184 if (ret == 0) { 185 /* Child process */ 186 errsave = errno; 187 curthread->cancel_pending = 0; 188 curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED); 189 190 /* 191 * Thread list will be reinitialized, and later we call 192 * _libpthread_init(), it will add us back to list. 193 */ 194 curthread->tlflags &= ~TLFLAGS_IN_TDLIST; 195 196 /* child is a new kernel thread. */ 197 thr_self(&curthread->tid); 198 199 /* clear other threads locked us. */ 200 _thr_umutex_init(&curthread->lock); 201 _mutex_fork(curthread); 202 203 _thr_signal_postfork_child(); 204 205 if (was_threaded) 206 _rtld_atfork_post(rtld_locks); 207 _thr_setthreaded(0); 208 209 /* reinitalize library. */ 210 _libpthread_init(curthread); 211 212 /* atfork is reinitialized by _libpthread_init()! */ 213 _thr_rwl_rdlock(&_thr_atfork_lock); 214 215 if (was_threaded) { 216 __isthreaded = 1; 217 _malloc_postfork(); 218 __isthreaded = 0; 219 } 220 221 /* Ready to continue, unblock signals. */ 222 _thr_signal_unblock(curthread); 223 224 /* Run down atfork child handlers. */ 225 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 226 if (af->child != NULL) 227 af->child(); 228 } 229 _thr_rwlock_unlock(&_thr_atfork_lock); 230 curthread->no_cancel = cancelsave; 231 } else { 232 /* Parent process */ 233 errsave = errno; 234 235 _thr_signal_postfork(); 236 237 if (was_threaded) { 238 _rtld_atfork_post(rtld_locks); 239 _malloc_postfork(); 240 } 241 242 /* Ready to continue, unblock signals. */ 243 _thr_signal_unblock(curthread); 244 245 /* Run down atfork parent handlers. */ 246 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 247 if (af->parent != NULL) 248 af->parent(); 249 } 250 251 _thr_rwlock_unlock(&_thr_atfork_lock); 252 curthread->no_cancel = cancelsave; 253 /* test async cancel */ 254 if (curthread->cancel_async) 255 _thr_testcancel(curthread); 256 } 257 errno = errsave; 258 259 return (ret); 260 } 261