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 28 /* 29 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 30 * All rights reserved. 31 * 32 * Redistribution and use in source and binary forms, with or without 33 * modification, are permitted provided that the following conditions 34 * are met: 35 * 1. Redistributions of source code must retain the above copyright 36 * notice, this list of conditions and the following disclaimer. 37 * 2. Redistributions in binary form must reproduce the above copyright 38 * notice, this list of conditions and the following disclaimer in the 39 * documentation and/or other materials provided with the distribution. 40 * 3. Neither the name of the author nor the names of any co-contributors 41 * may be used to endorse or promote products derived from this software 42 * without specific prior written permission. 43 * 44 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 45 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 46 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 47 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 48 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 49 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 50 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 51 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 52 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 53 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 54 * SUCH DAMAGE. 55 * 56 */ 57 58 #include <sys/cdefs.h> 59 __FBSDID("$FreeBSD$"); 60 61 #include <sys/syscall.h> 62 #include "namespace.h" 63 #include <errno.h> 64 #include <link.h> 65 #include <string.h> 66 #include <stdlib.h> 67 #include <unistd.h> 68 #include <pthread.h> 69 #include <spinlock.h> 70 #include "un-namespace.h" 71 72 #include "libc_private.h" 73 #include "rtld_lock.h" 74 #include "thr_private.h" 75 76 __weak_reference(_pthread_atfork, pthread_atfork); 77 78 int 79 _pthread_atfork(void (*prepare)(void), void (*parent)(void), 80 void (*child)(void)) 81 { 82 struct pthread *curthread; 83 struct pthread_atfork *af; 84 85 _thr_check_init(); 86 87 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 88 return (ENOMEM); 89 90 curthread = _get_curthread(); 91 af->prepare = prepare; 92 af->parent = parent; 93 af->child = child; 94 THR_CRITICAL_ENTER(curthread); 95 _thr_rwl_wrlock(&_thr_atfork_lock); 96 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 97 _thr_rwl_unlock(&_thr_atfork_lock); 98 THR_CRITICAL_LEAVE(curthread); 99 return (0); 100 } 101 102 void 103 __pthread_cxa_finalize(struct dl_phdr_info *phdr_info) 104 { 105 atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list); 106 struct pthread *curthread; 107 struct pthread_atfork *af, *af1; 108 109 _thr_check_init(); 110 111 curthread = _get_curthread(); 112 THR_CRITICAL_ENTER(curthread); 113 _thr_rwl_wrlock(&_thr_atfork_lock); 114 TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) { 115 if (__elf_phdr_match_addr(phdr_info, af->prepare) || 116 __elf_phdr_match_addr(phdr_info, af->parent) || 117 __elf_phdr_match_addr(phdr_info, af->child)) { 118 TAILQ_REMOVE(&_thr_atfork_list, af, qe); 119 TAILQ_INSERT_TAIL(&temp_list, af, qe); 120 } 121 } 122 _thr_rwl_unlock(&_thr_atfork_lock); 123 THR_CRITICAL_LEAVE(curthread); 124 while ((af = TAILQ_FIRST(&temp_list)) != NULL) { 125 TAILQ_REMOVE(&temp_list, af, qe); 126 free(af); 127 } 128 _thr_tsd_unload(phdr_info); 129 _thr_sigact_unload(phdr_info); 130 } 131 132 __weak_reference(__thr_fork, _fork); 133 134 pid_t 135 __thr_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 __thr_pshared_atfork_pre(); 173 _rtld_atfork_pre(rtld_locks); 174 } else { 175 was_threaded = 0; 176 } 177 178 /* 179 * Fork a new process. 180 * There is no easy way to pre-resolve the __sys_fork symbol 181 * without performing the fork. Use the syscall(2) 182 * indirection, the syscall symbol is resolved in 183 * _thr_rtld_init() with side-effect free call. 184 */ 185 ret = syscall(SYS_fork); 186 if (ret == 0) { 187 /* Child process */ 188 errsave = errno; 189 curthread->cancel_pending = 0; 190 curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED); 191 192 /* 193 * Thread list will be reinitialized, and later we call 194 * _libpthread_init(), it will add us back to list. 195 */ 196 curthread->tlflags &= ~TLFLAGS_IN_TDLIST; 197 198 /* child is a new kernel thread. */ 199 thr_self(&curthread->tid); 200 201 /* clear other threads locked us. */ 202 _thr_umutex_init(&curthread->lock); 203 _mutex_fork(curthread); 204 205 _thr_signal_postfork_child(); 206 207 if (was_threaded) { 208 _rtld_atfork_post(rtld_locks); 209 __thr_pshared_atfork_post(); 210 } 211 _thr_setthreaded(0); 212 213 /* reinitalize library. */ 214 _libpthread_init(curthread); 215 216 /* atfork is reinitialized by _libpthread_init()! */ 217 _thr_rwl_rdlock(&_thr_atfork_lock); 218 219 if (was_threaded) { 220 __isthreaded = 1; 221 _malloc_postfork(); 222 __isthreaded = 0; 223 } 224 225 /* Ready to continue, unblock signals. */ 226 _thr_signal_unblock(curthread); 227 228 /* Run down atfork child handlers. */ 229 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 230 if (af->child != NULL) 231 af->child(); 232 } 233 _thr_rwlock_unlock(&_thr_atfork_lock); 234 curthread->no_cancel = cancelsave; 235 } else { 236 /* Parent process */ 237 errsave = errno; 238 239 _thr_signal_postfork(); 240 241 if (was_threaded) { 242 _rtld_atfork_post(rtld_locks); 243 __thr_pshared_atfork_post(); 244 _malloc_postfork(); 245 } 246 247 /* Ready to continue, unblock signals. */ 248 _thr_signal_unblock(curthread); 249 250 /* Run down atfork parent handlers. */ 251 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 252 if (af->parent != NULL) 253 af->parent(); 254 } 255 256 _thr_rwlock_unlock(&_thr_atfork_lock); 257 curthread->no_cancel = cancelsave; 258 /* test async cancel */ 259 if (curthread->cancel_async) 260 _thr_testcancel(curthread); 261 } 262 errno = errsave; 263 264 return (ret); 265 } 266