2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
3 * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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
27 * $FreeBSD: head/lib/libthr/thread/thr_fork.c 213096 2010-08-23 $
31 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
32 * All rights reserved.
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
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.
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
60 #include "namespace.h"
61 #include <sys/syscall.h>
63 #include <machine/tls.h>
72 #include "un-namespace.h"
74 #include "libc_private.h"
75 #include "thr_private.h"
77 struct atfork_head _thr_atfork_list;
78 umtx_t _thr_atfork_lock;
81 _pthread_atfork(void (*prepare)(void), void (*parent)(void),
84 struct pthread *curthread;
85 struct pthread_atfork *af;
87 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL)
90 curthread = tls_get_curthread();
91 af->prepare = prepare;
94 THR_UMTX_LOCK(curthread, &_thr_atfork_lock);
95 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe);
96 THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock);
101 __pthread_cxa_finalize(struct dl_phdr_info *phdr_info)
103 struct pthread *curthread;
104 struct pthread_atfork *af, *af1;
106 curthread = tls_get_curthread();
107 THR_UMTX_LOCK(curthread, &_thr_atfork_lock);
108 TAILQ_FOREACH_MUTABLE(af, &_thr_atfork_list, qe, af1) {
109 if (__elf_phdr_match_addr(phdr_info, af->prepare) ||
110 __elf_phdr_match_addr(phdr_info, af->parent) ||
111 __elf_phdr_match_addr(phdr_info, af->child)) {
112 TAILQ_REMOVE(&_thr_atfork_list, af, qe);
116 THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock);
120 * For a while, allow libpthread to work with a libc that doesn't
121 * export the malloc lock.
123 #pragma weak __malloc_lock
130 static umtx_t inprogress;
134 struct pthread *curthread;
135 struct pthread_atfork *af;
138 #ifndef __DragonFly__
142 if (!_thr_is_inited())
143 return (__syscall(SYS_fork));
145 curthread = tls_get_curthread();
147 THR_UMTX_LOCK(curthread, &_thr_atfork_lock);
151 THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock);
152 _thr_umtx_wait(&inprogress, tmp, NULL, 0);
153 THR_UMTX_LOCK(curthread, &_thr_atfork_lock);
158 THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock);
160 /* Run down atfork prepare handlers. */
161 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) {
162 if (af->prepare != NULL)
166 #ifndef __DragonFly__
168 * Try our best to protect memory from being corrupted in
169 * child process because another thread in malloc code will
170 * simply be kill by fork().
172 if ((_thr_isthreaded() != 0) && (__malloc_lock != NULL)) {
174 _spinlock(__malloc_lock);
181 * Block all signals until we reach a safe point.
183 _thr_signal_block(curthread);
185 /* Fork a new process: */
186 if ((ret = __syscall(SYS_fork)) == 0) {
190 curthread->cancelflags &= ~THR_CANCEL_NEEDED;
192 * Thread list will be reinitialized, and later we call
193 * _libpthread_init(), it will add us back to list.
195 curthread->tlflags &= ~(TLFLAGS_IN_TDLIST | TLFLAGS_DETACHED);
197 /* child is a new kernel thread. */
198 curthread->tid = _thr_get_tid();
200 /* clear other threads locked us. */
201 _thr_umtx_init(&curthread->lock);
202 _thr_umtx_init(&_thr_atfork_lock);
205 /* reinitialize libc spinlocks, this includes __malloc_lock. */
206 _thr_spinlock_init();
207 _mutex_fork(curthread);
209 /* reinitalize library. */
210 _libpthread_init(curthread);
212 /* Ready to continue, unblock signals. */
213 _thr_signal_unblock(curthread);
215 /* Run down atfork child handlers. */
216 TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
217 if (af->child != NULL)
224 #ifndef __DragonFly__
226 _spinunlock(__malloc_lock);
229 /* Ready to continue, unblock signals. */
230 _thr_signal_unblock(curthread);
232 /* Run down atfork parent handlers. */
233 TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
234 if (af->parent != NULL)
238 THR_UMTX_LOCK(curthread, &_thr_atfork_lock);
241 _thr_umtx_wake(&inprogress, waiters);
242 THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock);
246 /* Return the process ID: */
250 __strong_reference(_fork, fork);
251 __strong_reference(_pthread_atfork, pthread_atfork);