/* * Copyright (c) 2005 David Xu * Copyright (c) 2003 Daniel Eischen * 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: src/lib/libpthread/thread/thr_atfork.c,v 1.1 2003/11/05 03:42:10 davidxu Exp $ */ /* * Copyright (c) 1995-1998 John Birrell * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by John Birrell. * 4. 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. * * $FreeBSD: src/lib/libpthread/thread/thr_fork.c,v 1.34 2003/11/05 18:18:45 deischen Exp $ * $DragonFly: src/lib/libthread_xu/thread/thr_fork.c,v 1.3 2005/03/29 19:26:20 joerg Exp $ */ #include #include #include #include #include #include #include #include #include "libc_private.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 = tls_get_curthread(); af->prepare = prepare; af->parent = parent; af->child = child; THR_UMTX_LOCK(curthread, &_thr_atfork_lock); TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock); return (0); } /* * For a while, allow libpthread to work with a libc that doesn't * export the malloc lock. */ #pragma weak __malloc_lock __weak_reference(_fork, fork); pid_t _fork(void) { static umtx_t inprogress; static int waiters; umtx_t tmp; struct pthread *curthread; struct pthread_atfork *af; pid_t ret; int errsave; #ifndef __DragonFly__ int unlock_malloc; #endif if (!_thr_is_inited()) return (__sys_fork()); curthread = tls_get_curthread(); THR_UMTX_LOCK(curthread, &_thr_atfork_lock); tmp = inprogress; while (tmp) { waiters++; THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock); _thr_umtx_wait(&inprogress, tmp, NULL, 0); THR_UMTX_LOCK(curthread, &_thr_atfork_lock); waiters--; tmp = inprogress; } inprogress = 1; THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock); /* Run down atfork prepare handlers. */ TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { if (af->prepare != NULL) af->prepare(); } #ifndef __DragonFly__ /* * Try our best to protect memory from being corrupted in * child process because another thread in malloc code will * simply be kill by fork(). */ if ((_thr_isthreaded() != 0) && (__malloc_lock != NULL)) { unlock_malloc = 1; _spinlock(__malloc_lock); } else { unlock_malloc = 0; } #endif /* * Block all signals until we reach a safe point. */ _thr_signal_block(curthread); /* Fork a new process: */ if ((ret = __sys_fork()) == 0) { /* Child process */ errsave = errno; inprogress = 0; curthread->cancelflags &= ~THR_CANCEL_NEEDED; /* * Thread list will be reinitialized, and later we call * _libpthread_init(), it will add us back to list. */ curthread->tlflags &= ~(TLFLAGS_IN_TDLIST | TLFLAGS_DETACHED); /* child is a new kernel thread. */ curthread->tid = _thr_get_tid(); /* clear other threads locked us. */ _thr_umtx_init(&curthread->lock); _thr_umtx_init(&_thr_atfork_lock); _thr_setthreaded(0); /* reinitialize libc spinlocks, this includes __malloc_lock. */ _thr_spinlock_init(); _mutex_fork(curthread); /* reinitalize library. */ _libpthread_init(curthread); /* 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(); } } else { /* Parent process */ errsave = errno; #ifndef __DragonFly__ if (unlock_malloc) _spinunlock(__malloc_lock); #endif /* 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_UMTX_LOCK(curthread, &_thr_atfork_lock); inprogress = 0; if (waiters) _thr_umtx_wake(&inprogress, waiters); THR_UMTX_UNLOCK(curthread, &_thr_atfork_lock); } errno = errsave; /* Return the process ID: */ return (ret); }