diff options
Diffstat (limited to 'lib/libthr/thread/thr_fork.c')
-rw-r--r-- | lib/libthr/thread/thr_fork.c | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_fork.c b/lib/libthr/thread/thr_fork.c new file mode 100644 index 0000000..a1399bf --- /dev/null +++ b/lib/libthr/thread/thr_fork.c @@ -0,0 +1,258 @@ +/* + * 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); +} |