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-rw-r--r--lib/libthr/thread/thr_fork.c258
1 files changed, 258 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_fork.c b/lib/libthr/thread/thr_fork.c
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+/*
+ * Copyright (c) 2005 David Xu <davidxu@freebsd.org>
+ * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+/*
+ * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ */
+
+#include "namespace.h"
+#include <errno.h>
+#include <link.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <pthread.h>
+#include <spinlock.h>
+#include "un-namespace.h"
+
+#include "libc_private.h"
+#include "rtld_lock.h"
+#include "thr_private.h"
+
+__weak_reference(_pthread_atfork, pthread_atfork);
+
+int
+_pthread_atfork(void (*prepare)(void), void (*parent)(void),
+ void (*child)(void))
+{
+ struct pthread *curthread;
+ struct pthread_atfork *af;
+
+ _thr_check_init();
+
+ if ((af = malloc(sizeof(struct pthread_atfork))) == NULL)
+ return (ENOMEM);
+
+ curthread = _get_curthread();
+ af->prepare = prepare;
+ af->parent = parent;
+ af->child = child;
+ THR_CRITICAL_ENTER(curthread);
+ _thr_rwl_wrlock(&_thr_atfork_lock);
+ TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe);
+ _thr_rwl_unlock(&_thr_atfork_lock);
+ THR_CRITICAL_LEAVE(curthread);
+ return (0);
+}
+
+void
+__pthread_cxa_finalize(struct dl_phdr_info *phdr_info)
+{
+ atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list);
+ struct pthread *curthread;
+ struct pthread_atfork *af, *af1;
+
+ _thr_check_init();
+
+ curthread = _get_curthread();
+ THR_CRITICAL_ENTER(curthread);
+ _thr_rwl_wrlock(&_thr_atfork_lock);
+ TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) {
+ if (__elf_phdr_match_addr(phdr_info, af->prepare) ||
+ __elf_phdr_match_addr(phdr_info, af->parent) ||
+ __elf_phdr_match_addr(phdr_info, af->child)) {
+ TAILQ_REMOVE(&_thr_atfork_list, af, qe);
+ TAILQ_INSERT_TAIL(&temp_list, af, qe);
+ }
+ }
+ _thr_rwl_unlock(&_thr_atfork_lock);
+ THR_CRITICAL_LEAVE(curthread);
+ while ((af = TAILQ_FIRST(&temp_list)) != NULL) {
+ TAILQ_REMOVE(&temp_list, af, qe);
+ free(af);
+ }
+ _thr_tsd_unload(phdr_info);
+ _thr_sigact_unload(phdr_info);
+}
+
+__weak_reference(_fork, fork);
+
+pid_t _fork(void);
+
+pid_t
+_fork(void)
+{
+ struct pthread *curthread;
+ struct pthread_atfork *af;
+ pid_t ret;
+ int errsave, cancelsave;
+ int was_threaded;
+ int rtld_locks[MAX_RTLD_LOCKS];
+
+ if (!_thr_is_inited())
+ return (__sys_fork());
+
+ curthread = _get_curthread();
+ cancelsave = curthread->no_cancel;
+ curthread->no_cancel = 1;
+ _thr_rwl_rdlock(&_thr_atfork_lock);
+
+ /* Run down atfork prepare handlers. */
+ TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) {
+ if (af->prepare != NULL)
+ af->prepare();
+ }
+
+ /*
+ * Block all signals until we reach a safe point.
+ */
+ _thr_signal_block(curthread);
+ _thr_signal_prefork();
+
+ /*
+ * All bets are off as to what should happen soon if the parent
+ * process was not so kindly as to set up pthread fork hooks to
+ * relinquish all running threads.
+ */
+ if (_thr_isthreaded() != 0) {
+ was_threaded = 1;
+ _malloc_prefork();
+ _rtld_atfork_pre(rtld_locks);
+ } else {
+ was_threaded = 0;
+ }
+
+ /* Fork a new process: */
+ if ((ret = __sys_fork()) == 0) {
+ /* Child process */
+ errsave = errno;
+ curthread->cancel_pending = 0;
+ curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED);
+
+ /*
+ * Thread list will be reinitialized, and later we call
+ * _libpthread_init(), it will add us back to list.
+ */
+ curthread->tlflags &= ~TLFLAGS_IN_TDLIST;
+
+ /* child is a new kernel thread. */
+ thr_self(&curthread->tid);
+
+ /* clear other threads locked us. */
+ _thr_umutex_init(&curthread->lock);
+ _mutex_fork(curthread);
+
+ _thr_signal_postfork_child();
+
+ if (was_threaded)
+ _rtld_atfork_post(rtld_locks);
+ _thr_setthreaded(0);
+
+ /* reinitialize libc spinlocks. */
+ _thr_spinlock_init();
+
+ /* reinitalize library. */
+ _libpthread_init(curthread);
+
+ /* atfork is reinitializeded by _libpthread_init()! */
+ _thr_rwl_rdlock(&_thr_atfork_lock);
+
+ if (was_threaded) {
+ __isthreaded = 1;
+ _malloc_postfork();
+ __isthreaded = 0;
+ }
+
+ /* Ready to continue, unblock signals. */
+ _thr_signal_unblock(curthread);
+
+ /* Run down atfork child handlers. */
+ TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
+ if (af->child != NULL)
+ af->child();
+ }
+ _thr_rwlock_unlock(&_thr_atfork_lock);
+ curthread->no_cancel = cancelsave;
+ } else {
+ /* Parent process */
+ errsave = errno;
+
+ _thr_signal_postfork();
+
+ if (was_threaded) {
+ _rtld_atfork_post(rtld_locks);
+ _malloc_postfork();
+ }
+
+ /* Ready to continue, unblock signals. */
+ _thr_signal_unblock(curthread);
+
+ /* Run down atfork parent handlers. */
+ TAILQ_FOREACH(af, &_thr_atfork_list, qe) {
+ if (af->parent != NULL)
+ af->parent();
+ }
+
+ _thr_rwlock_unlock(&_thr_atfork_lock);
+ curthread->no_cancel = cancelsave;
+ /* test async cancel */
+ if (curthread->cancel_async)
+ _thr_testcancel(curthread);
+ }
+ errno = errsave;
+
+ /* Return the process ID: */
+ return (ret);
+}
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