205 lines
6.2 KiB
C
205 lines
6.2 KiB
C
/*
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <pthread.h>
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#include "thr_private.h"
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__weak_reference(_pthread_exit, pthread_exit);
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/* thr_exit() */
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extern int _thr_exit(void);
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void
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_thread_exit(char *fname, int lineno, char *string)
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{
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char s[256];
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/* Prepare an error message string: */
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snprintf(s, sizeof(s),
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"Fatal error '%s' at line %d in file %s (errno = %d)\n",
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string, lineno, fname, errno);
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/* Write the string to the standard error file descriptor: */
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__sys_write(2, s, strlen(s));
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/* Force this process to exit: */
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/* XXX - Do we want abort to be conditional on _PTHREADS_INVARIANTS? */
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#if defined(_PTHREADS_INVARIANTS)
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abort();
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#else
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__sys_exit(1);
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#endif
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}
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/*
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* Only called when a thread is cancelled. It may be more useful
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* to call it from pthread_exit() if other ways of asynchronous or
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* abnormal thread termination can be found.
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*/
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void
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_thread_exit_cleanup(void)
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{
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/*
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* POSIX states that cancellation/termination of a thread should
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* not release any visible resources (such as mutexes) and that
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* it is the applications responsibility. Resources that are
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* internal to the threads library, including file and fd locks,
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* are not visible to the application and need to be released.
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*/
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/* Unlock all private mutexes: */
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_mutex_unlock_private(curthread);
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/*
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* This still isn't quite correct because we don't account
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* for held spinlocks (see libc/stdlib/malloc.c).
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*/
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}
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void
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_pthread_exit(void *status)
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{
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pthread_t pthread, joiner;
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int exitNow = 0;
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/* Check if this thread is already in the process of exiting: */
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if ((curthread->flags & PTHREAD_EXITING) != 0) {
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char msg[128];
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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);
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PANIC(msg);
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}
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/* Flag this thread as exiting: */
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curthread->flags |= PTHREAD_EXITING;
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/* Save the return value: */
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curthread->ret = status;
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while (curthread->cleanup != NULL) {
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pthread_cleanup_pop(1);
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}
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if (curthread->attr.cleanup_attr != NULL) {
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curthread->attr.cleanup_attr(curthread->attr.arg_attr);
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}
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/* Check if there is thread specific data: */
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if (curthread->specific != NULL) {
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/* Run the thread-specific data destructors: */
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_thread_cleanupspecific();
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}
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retry:
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/*
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* Proper lock order, to minimize deadlocks, between joining
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* and exiting threads is: DEAD_LIST, THREAD_LIST, exiting, joiner.
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* In order to do this *and* protect from races, we must resort
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* this test-and-retry loop.
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*/
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joiner = curthread->joiner;
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/* Lock the dead list first to maintain correct lock order */
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DEAD_LIST_LOCK;
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THREAD_LIST_LOCK;
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_thread_critical_enter(curthread);
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if (joiner != curthread->joiner) {
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_thread_critical_exit(curthread);
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THREAD_LIST_UNLOCK;
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DEAD_LIST_UNLOCK;
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goto retry;
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}
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/* Check if there is a thread joining this one: */
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if (curthread->joiner != NULL) {
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pthread = curthread->joiner;
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UMTX_LOCK(&pthread->lock);
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curthread->joiner = NULL;
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/* Make the joining thread runnable: */
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PTHREAD_NEW_STATE(pthread, PS_RUNNING);
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/* Set the return value for the joining thread: */
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pthread->join_status.ret = curthread->ret;
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pthread->join_status.error = 0;
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pthread->join_status.thread = NULL;
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UMTX_UNLOCK(&pthread->lock);
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/* Make this thread collectable by the garbage collector. */
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PTHREAD_ASSERT(((curthread->attr.flags & PTHREAD_DETACHED) ==
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0), "Cannot join a detached thread");
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curthread->attr.flags |= PTHREAD_DETACHED;
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}
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/*
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* Add this thread to the list of dead threads, and
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* also remove it from the active threads list.
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*/
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TAILQ_INSERT_HEAD(&_dead_list, curthread, dle);
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TAILQ_REMOVE(&_thread_list, curthread, tle);
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PTHREAD_SET_STATE(curthread, PS_DEAD);
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_thread_critical_exit(curthread);
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/* If we're the last thread, call it quits */
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if (TAILQ_EMPTY(&_thread_list))
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exitNow = 1;
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THREAD_LIST_UNLOCK;
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/*
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* Signal the garbage collector thread that there is something
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* to clean up. But don't allow it to free the memory until after
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* it is retired by holding on to the dead list lock.
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*/
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if (pthread_cond_signal(&_gc_cond) != 0)
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PANIC("Cannot signal gc cond");
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if (exitNow)
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exit(0);
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DEAD_LIST_UNLOCK;
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/*
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* This function will not return unless we are the last
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* thread, which we can't be because we've already checked
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* for that.
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*/
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_thr_exit();
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/* This point should not be reached. */
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PANIC("Dead thread has resumed");
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}
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