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 __thr_pshared_atfork_pre(); 172 _rtld_atfork_pre(rtld_locks); 173 } else { 174 was_threaded = 0; 175 } 176 177 /* 178 * Fork a new process. 179 * There is no easy way to pre-resolve the __sys_fork symbol 180 * without performing the fork. Use the syscall(2) 181 * indirection, the syscall symbol is resolved in 182 * _thr_rtld_init() with side-effect free call. 183 */ 184 ret = syscall(SYS_fork); 185 if (ret == 0) { 186 /* Child process */ 187 errsave = errno; 188 curthread->cancel_pending = 0; 189 curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED); 190 191 /* 192 * Thread list will be reinitialized, and later we call 193 * _libpthread_init(), it will add us back to list. 194 */ 195 curthread->tlflags &= ~TLFLAGS_IN_TDLIST; 196 197 /* child is a new kernel thread. */ 198 thr_self(&curthread->tid); 199 200 /* clear other threads locked us. */ 201 _thr_umutex_init(&curthread->lock); 202 _mutex_fork(curthread); 203 204 _thr_signal_postfork_child(); 205 206 if (was_threaded) { 207 _rtld_atfork_post(rtld_locks); 208 __thr_pshared_atfork_post(); 209 } 210 _thr_setthreaded(0); 211 212 /* reinitalize library. */ 213 _libpthread_init(curthread); 214 215 /* atfork is reinitialized by _libpthread_init()! */ 216 _thr_rwl_rdlock(&_thr_atfork_lock); 217 218 if (was_threaded) { 219 __isthreaded = 1; 220 _malloc_postfork(); 221 __isthreaded = 0; 222 } 223 224 /* Ready to continue, unblock signals. */ 225 _thr_signal_unblock(curthread); 226 227 /* Run down atfork child handlers. */ 228 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 229 if (af->child != NULL) 230 af->child(); 231 } 232 _thr_rwlock_unlock(&_thr_atfork_lock); 233 curthread->no_cancel = cancelsave; 234 } else { 235 /* Parent process */ 236 errsave = errno; 237 238 _thr_signal_postfork(); 239 240 if (was_threaded) { 241 _rtld_atfork_post(rtld_locks); 242 __thr_pshared_atfork_post(); 243 _malloc_postfork(); 244 } 245 246 /* Ready to continue, unblock signals. */ 247 _thr_signal_unblock(curthread); 248 249 /* Run down atfork parent handlers. */ 250 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 251 if (af->parent != NULL) 252 af->parent(); 253 } 254 255 _thr_rwlock_unlock(&_thr_atfork_lock); 256 curthread->no_cancel = cancelsave; 257 /* test async cancel */ 258 if (curthread->cancel_async) 259 _thr_testcancel(curthread); 260 } 261 errno = errsave; 262 263 return (ret); 264 } 265