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 "thr_private.h" 71 72 __weak_reference(_pthread_atfork, pthread_atfork); 73 74 int 75 _pthread_atfork(void (*prepare)(void), void (*parent)(void), 76 void (*child)(void)) 77 { 78 struct pthread *curthread; 79 struct pthread_atfork *af; 80 81 _thr_check_init(); 82 83 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 84 return (ENOMEM); 85 86 curthread = _get_curthread(); 87 af->prepare = prepare; 88 af->parent = parent; 89 af->child = child; 90 THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock); 91 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 92 THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock); 93 return (0); 94 } 95 96 __weak_reference(_fork, fork); 97 98 pid_t _fork(void); 99 100 pid_t 101 _fork(void) 102 { 103 struct pthread *curthread; 104 struct pthread_atfork *af; 105 pid_t ret; 106 int errsave; 107 int unlock_malloc; 108 109 if (!_thr_is_inited()) 110 return (__sys_fork()); 111 112 curthread = _get_curthread(); 113 114 THR_UMUTEX_LOCK(curthread, &_thr_atfork_lock); 115 116 /* Run down atfork prepare handlers. */ 117 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { 118 if (af->prepare != NULL) 119 af->prepare(); 120 } 121 122 /* 123 * Try our best to protect memory from being corrupted in 124 * child process because another thread in malloc code will 125 * simply be kill by fork(). 126 */ 127 if (_thr_isthreaded() != 0) { 128 unlock_malloc = 1; 129 _malloc_prefork(); 130 } else { 131 unlock_malloc = 0; 132 } 133 134 /* 135 * Block all signals until we reach a safe point. 136 */ 137 _thr_signal_block(curthread); 138 139 /* Fork a new process: */ 140 if ((ret = __sys_fork()) == 0) { 141 /* Child process */ 142 errsave = errno; 143 curthread->cancel_pending = 0; 144 curthread->flags &= ~THR_FLAGS_NEED_SUSPEND; 145 146 /* 147 * Thread list will be reinitialized, and later we call 148 * _libpthread_init(), it will add us back to list. 149 */ 150 curthread->tlflags &= ~(TLFLAGS_IN_TDLIST | TLFLAGS_DETACHED); 151 152 /* child is a new kernel thread. */ 153 thr_self(&curthread->tid); 154 155 /* clear other threads locked us. */ 156 _thr_umutex_init(&curthread->lock); 157 _thr_umutex_init(&_thr_atfork_lock); 158 _thr_setthreaded(0); 159 160 /* reinitialize libc spinlocks. */ 161 _thr_spinlock_init(); 162 _mutex_fork(curthread); 163 164 /* reinitalize library. */ 165 _libpthread_init(curthread); 166 167 /* Ready to continue, unblock signals. */ 168 _thr_signal_unblock(curthread); 169 170 /* Run down atfork child handlers. */ 171 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 172 if (af->child != NULL) 173 af->child(); 174 } 175 } else { 176 /* Parent process */ 177 errsave = errno; 178 179 /* Ready to continue, unblock signals. */ 180 _thr_signal_unblock(curthread); 181 182 if (unlock_malloc) 183 _malloc_postfork(); 184 185 /* Run down atfork parent handlers. */ 186 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 187 if (af->parent != NULL) 188 af->parent(); 189 } 190 191 THR_UMUTEX_UNLOCK(curthread, &_thr_atfork_lock); 192 } 193 errno = errsave; 194 195 /* Return the process ID: */ 196 return (ret); 197 } 198