6699b0c6fe
keep track of a joiner. POSIX only supports a single joiner, so this simplification is acceptable. At the same time, make sure to mark a joined thread as detached so that its resources can be freed. Reviewed by: deischen PR: 24345
120 lines
4.0 KiB
C
120 lines
4.0 KiB
C
/*
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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 "pthread_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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struct pthread *curthread = _get_curthread();
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int ret = 0;
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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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* Find the thread in the list of active threads or in the
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* list of dead threads:
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*/
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if ((_find_thread(pthread) != 0) && (_find_dead_thread(pthread) != 0))
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/* Return an error: */
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ret = ESRCH;
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/* Check if this thread has been detached: */
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else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0)
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/* Return an error: */
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ret = ESRCH;
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else if (pthread->joiner != NULL)
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/* Multiple joiners are not supported. */
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ret = ENOTSUP;
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/* Check if the thread is not dead: */
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else 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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/* Schedule the next thread: */
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_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
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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->error;
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if ((ret == 0) && (thread_return != NULL))
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*thread_return = curthread->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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/*
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* Make the thread collectable by the garbage collector. There
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* is a race here with the garbage collector if multiple threads
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* try to join the thread, but the behavior of multiple joiners
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* is undefined, so don't bother protecting against the race.
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*/
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pthread->attr.flags |= PTHREAD_DETACHED;
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}
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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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