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 <string.h> 63 #include <stdlib.h> 64 #include <unistd.h> 65 #include <pthread.h> 66 #include <spinlock.h> 67 #include "un-namespace.h" 68 69 #include "libc_private.h" 70 #include "rtld_lock.h" 71 #include "thr_private.h" 72 73 __weak_reference(_pthread_atfork, pthread_atfork); 74 75 int 76 _pthread_atfork(void (*prepare)(void), void (*parent)(void), 77 void (*child)(void)) 78 { 79 struct pthread *curthread; 80 struct pthread_atfork *af; 81 82 _thr_check_init(); 83 84 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 85 return (ENOMEM); 86 87 curthread = _get_curthread(); 88 af->prepare = prepare; 89 af->parent = parent; 90 af->child = child; 91 THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock); 92 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 93 THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock); 94 return (0); 95 } 96 97 __weak_reference(_fork, fork); 98 99 pid_t _fork(void); 100 101 pid_t 102 _fork(void) 103 { 104 struct pthread *curthread; 105 struct pthread_atfork *af; 106 pid_t ret; 107 int errsave; 108 int was_threaded; 109 int rtld_locks[MAX_RTLD_LOCKS]; 110 111 if (!_thr_is_inited()) 112 return (__sys_fork()); 113 114 curthread = _get_curthread(); 115 116 THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock); 117 118 /* Run down atfork prepare handlers. */ 119 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { 120 if (af->prepare != NULL) 121 af->prepare(); 122 } 123 124 /* 125 * All bets are off as to what should happen soon if the parent 126 * process was not so kindly as to set up pthread fork hooks to 127 * relinquish all running threads. 128 */ 129 if (_thr_isthreaded() != 0) { 130 was_threaded = 1; 131 _malloc_prefork(); 132 _rtld_atfork_pre(rtld_locks); 133 } else { 134 was_threaded = 0; 135 } 136 137 /* 138 * Block all signals until we reach a safe point. 139 */ 140 _thr_signal_block(curthread); 141 142 /* Fork a new process: */ 143 if ((ret = __sys_fork()) == 0) { 144 /* Child process */ 145 errsave = errno; 146 curthread->cancel_pending = 0; 147 curthread->flags &= ~THR_FLAGS_NEED_SUSPEND; 148 149 /* 150 * Thread list will be reinitialized, and later we call 151 * _libpthread_init(), it will add us back to list. 152 */ 153 curthread->tlflags &= ~(TLFLAGS_IN_TDLIST | TLFLAGS_DETACHED); 154 155 /* child is a new kernel thread. */ 156 thr_self(&curthread->tid); 157 158 /* clear other threads locked us. */ 159 _thr_umutex_init(&curthread->lock); 160 _thr_umutex_init(&_thr_atfork_lock); 161 162 if (was_threaded) 163 _rtld_atfork_post(rtld_locks); 164 _thr_setthreaded(0); 165 166 /* reinitialize libc spinlocks. */ 167 _thr_spinlock_init(); 168 _mutex_fork(curthread); 169 170 /* reinitalize library. */ 171 _libpthread_init(curthread); 172 173 /* Ready to continue, unblock signals. */ 174 _thr_signal_unblock(curthread); 175 176 if (was_threaded) { 177 __isthreaded = 1; 178 _malloc_postfork(); 179 __isthreaded = 0; 180 } 181 182 /* Run down atfork child handlers. */ 183 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 184 if (af->child != NULL) 185 af->child(); 186 } 187 } else { 188 /* Parent process */ 189 errsave = errno; 190 191 /* Ready to continue, unblock signals. */ 192 _thr_signal_unblock(curthread); 193 194 if (was_threaded) { 195 _rtld_atfork_post(rtld_locks); 196 _malloc_postfork(); 197 } 198 199 /* Run down atfork parent handlers. */ 200 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 201 if (af->parent != NULL) 202 af->parent(); 203 } 204 205 THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock); 206 } 207 errno = errsave; 208 209 /* Return the process ID: */ 210 return (ret); 211 } 212