2003-04-01 03:46:29 +00:00
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/*
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* Copyright (c) 1995 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 <pthread.h>
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#include "thr_private.h"
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__weak_reference(_pthread_join, pthread_join);
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int
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_pthread_join(pthread_t pthread, void **thread_return)
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{
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int ret = 0;
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pthread_t thread;
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_thread_enter_cancellation_point();
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/* Check if the caller has specified an invalid thread: */
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if (pthread == NULL || pthread->magic != PTHREAD_MAGIC) {
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/* Invalid thread: */
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_thread_leave_cancellation_point();
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return(EINVAL);
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}
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/* Check if the caller has specified itself: */
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if (pthread == curthread) {
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/* Avoid a deadlock condition: */
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_thread_leave_cancellation_point();
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return(EDEADLK);
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}
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/*
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* Lock the garbage collector mutex to ensure that the garbage
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* collector is not using the dead thread list.
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*/
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if (pthread_mutex_lock(&_gc_mutex) != 0)
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PANIC("Cannot lock gc mutex");
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GIANT_LOCK(curthread);
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/*
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* Search for the specified thread in the list of active threads. This
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* is done manually here rather than calling _find_thread() because
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* the searches in _thread_list and _dead_list (as well as setting up
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* join/detach state) have to be done atomically.
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*/
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TAILQ_FOREACH(thread, &_thread_list, tle)
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if (thread == pthread)
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break;
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if (thread == NULL)
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/*
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* Search for the specified thread in the list of dead threads:
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*/
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TAILQ_FOREACH(thread, &_dead_list, dle)
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if (thread == pthread)
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break;
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/* Check if the thread was not found or has been detached: */
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if (thread == NULL ||
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((pthread->attr.flags & PTHREAD_DETACHED) != 0)) {
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if (pthread_mutex_unlock(&_gc_mutex) != 0)
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PANIC("Cannot lock gc mutex");
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ret = ESRCH;
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goto out;
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}
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if (pthread->joiner != NULL) {
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/* Multiple joiners are not supported. */
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/* XXXTHR - support multiple joiners. */
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if (pthread_mutex_unlock(&_gc_mutex) != 0)
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PANIC("Cannot lock gc mutex");
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ret = ENOTSUP;
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goto out;
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/* Check if the thread is not dead: */
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}
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/*
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* Unlock the garbage collector mutex, now that the garbage collector
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* can't be run:
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*/
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if (pthread_mutex_unlock(&_gc_mutex) != 0)
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PANIC("Cannot lock gc mutex");
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if (pthread->state != PS_DEAD) {
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/* Set the running thread to be the joiner: */
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pthread->joiner = curthread;
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/* Keep track of which thread we're joining to: */
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curthread->join_status.thread = pthread;
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while (curthread->join_status.thread == pthread) {
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PTHREAD_SET_STATE(curthread, PS_JOIN);
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/* Wait for our signal to wake up. */
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2003-04-01 22:41:41 +00:00
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GIANT_UNLOCK(curthread);
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2003-04-01 03:46:29 +00:00
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_thread_suspend(curthread, NULL);
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2003-04-01 22:41:41 +00:00
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GIANT_LOCK(curthread);
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2003-04-01 03:46:29 +00:00
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}
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/*
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* The thread return value and error are set by the thread we're
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* joining to when it exits or detaches:
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*/
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ret = curthread->join_status.error;
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if ((ret == 0) && (thread_return != NULL))
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*thread_return = curthread->join_status.ret;
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} else {
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/*
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* The thread exited (is dead) without being detached, and no
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* thread has joined it.
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*/
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/* Check if the return value is required: */
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if (thread_return != NULL) {
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/* Return the thread's return value: */
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*thread_return = pthread->ret;
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}
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/* Make the thread collectable by the garbage collector. */
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pthread->attr.flags |= PTHREAD_DETACHED;
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}
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out:
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GIANT_UNLOCK(curthread);
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_thread_leave_cancellation_point();
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/* Return the completion status: */
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return (ret);
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}
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