/* * 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: head/lib/libthr/thread/thr_exit.c 115357 2003-05-27 21:48:42Z mtm $ */ #include #include #include #include #include #include #include #include "thr_private.h" __weak_reference(_pthread_exit, pthread_exit); /* thr_exit() */ extern int _thr_exit(void); void _thread_exit(char *fname, int lineno, char *string) { char s[256]; /* Prepare an error message string: */ snprintf(s, sizeof(s), "Fatal error '%s' at line %d in file %s (errno = %d)\n", string, lineno, fname, errno); /* Write the string to the standard error file descriptor: */ __sys_write(2, s, strlen(s)); /* Force this process to exit: */ /* XXX - Do we want abort to be conditional on _PTHREADS_INVARIANTS? */ #if defined(_PTHREADS_INVARIANTS) abort(); #else __sys_exit(1); #endif } /* * Only called when a thread is cancelled. It may be more useful * to call it from pthread_exit() if other ways of asynchronous or * abnormal thread termination can be found. */ void _thread_exit_cleanup(void) { /* * POSIX states that cancellation/termination of a thread should * not release any visible resources (such as mutexes) and that * it is the applications responsibility. Resources that are * internal to the threads library, including file and fd locks, * are not visible to the application and need to be released. */ /* Unlock all private mutexes: */ _mutex_unlock_private(curthread); /* * This still isn't quite correct because we don't account * for held spinlocks (see libc/stdlib/malloc.c). */ } void _pthread_exit(void *status) { pthread_t pthread, joiner; int exitNow = 0; /* Check if this thread is already in the process of exiting: */ if ((curthread->flags & PTHREAD_EXITING) != 0) { char msg[128]; snprintf(msg, sizeof(msg), "Thread %p has called pthread_exit() from a destructor. POSIX 1003.1 1996 s16.2.5.2 does not allow this!",curthread); PANIC(msg); } /* Flag this thread as exiting: */ curthread->flags |= PTHREAD_EXITING; /* Save the return value: */ curthread->ret = status; while (curthread->cleanup != NULL) { pthread_cleanup_pop(1); } if (curthread->attr.cleanup_attr != NULL) { curthread->attr.cleanup_attr(curthread->attr.arg_attr); } /* Check if there is thread specific data: */ if (curthread->specific != NULL) { /* Run the thread-specific data destructors: */ _thread_cleanupspecific(); } retry: /* * Proper lock order, to minimize deadlocks, between joining * and exiting threads is: DEAD_LIST, THREAD_LIST, exiting, joiner. * In order to do this *and* protect from races, we must resort * this test-and-retry loop. */ joiner = curthread->joiner; /* Lock the dead list first to maintain correct lock order */ DEAD_LIST_LOCK; THREAD_LIST_LOCK; _thread_critical_enter(curthread); if (joiner != curthread->joiner) { _thread_critical_exit(curthread); THREAD_LIST_UNLOCK; DEAD_LIST_UNLOCK; goto retry; } /* Check if there is a thread joining this one: */ if (curthread->joiner != NULL) { pthread = curthread->joiner; _SPINLOCK(&pthread->lock); curthread->joiner = NULL; /* Make the joining thread runnable: */ PTHREAD_NEW_STATE(pthread, PS_RUNNING); /* Set the return value for the joining thread: */ pthread->join_status.ret = curthread->ret; pthread->join_status.error = 0; pthread->join_status.thread = NULL; _SPINUNLOCK(&pthread->lock); /* Make this thread collectable by the garbage collector. */ PTHREAD_ASSERT(((curthread->attr.flags & PTHREAD_DETACHED) == 0), "Cannot join a detached thread"); curthread->attr.flags |= PTHREAD_DETACHED; } /* * Add this thread to the list of dead threads, and * also remove it from the active threads list. */ TAILQ_INSERT_HEAD(&_dead_list, curthread, dle); TAILQ_REMOVE(&_thread_list, curthread, tle); PTHREAD_SET_STATE(curthread, PS_DEAD); _thread_critical_exit(curthread); /* * Signal the garbage collector thread that there is something * to clean up. */ if (pthread_cond_signal(&_gc_cond) != 0) PANIC("Cannot signal gc cond"); /* If we're the last thread, call it quits */ if (TAILQ_EMPTY(&_thread_list)) exitNow = 1; THREAD_LIST_UNLOCK; DEAD_LIST_UNLOCK; if (exitNow) exit(0); /* * Retire the architecture specific id so that it can be used for * new threads. */ _retire_thread(curthread->arch_id); _thr_exit(); /* This point should not be reached. */ PANIC("Dead thread has resumed"); }