114 lines
3.6 KiB
C
114 lines
3.6 KiB
C
/* ==== pthread_join.c =======================================================
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* Copyright (c) 1994 by Chris Provenzano, proven@mit.edu
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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 Chris Provenzano.
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* 4. The name of Chris Provenzano may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``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 CHRIS PROVENZANO BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* 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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* Description : pthread_join function.
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*
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* 1.00 94/01/15 proven
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* -Started coding this file.
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*/
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#ifndef lint
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static const char rcsid[] = "$Id: pthread_join.c,v 1.1 1994/02/07 22:04:26 proven Exp $ $provenid: pthread_join.c,v 1.16 1994/02/07 02:19:19 proven Exp $";
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#endif
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#include <pthread.h>
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/* ==========================================================================
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* pthread_join()
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*/
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int pthread_join(pthread_t pthread, void **thread_return)
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{
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semaphore *lock, *plock;
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int ret;
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plock = &(pthread->lock);
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while (SEMAPHORE_TEST_AND_SET(plock)) {
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pthread_yield();
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}
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/* Check that thread isn't detached already */
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if (pthread->flags & PF_DETACHED) {
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SEMAPHORE_RESET(plock);
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return(ESRCH);
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}
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lock = &(pthread_run->lock);
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while (SEMAPHORE_TEST_AND_SET(lock)) {
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pthread_yield();
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}
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/* If OK then queue current thread. */
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pthread_queue(&(pthread->join_queue), pthread_run);
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SEMAPHORE_RESET(plock);
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reschedule(PS_JOIN);
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/*
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* At this point the thread is locked from the pthread_exit
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* and so are we, so no extra locking is required, but be sure
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* to unlock at least ourself.
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*/
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if (!(pthread->flags & PF_DETACHED)) {
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if (thread_return) {
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*thread_return = pthread->ret;
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}
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pthread->flags |= PF_DETACHED;
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ret = OK;
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} else {
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ret = ESRCH;
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}
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/* Cant do a cleanup until queue is cleared */
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{
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struct pthread * next_thread;
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semaphore * next_lock;
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if (next_thread = pthread_queue_get(&(pthread->join_queue))) {
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next_lock = &(next_thread->lock);
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while (SEMAPHORE_TEST_AND_SET(next_lock)) {
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pthread_yield();
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}
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pthread_queue_deq(&(pthread->join_queue));
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next_thread->state = PS_RUNNING;
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/*
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* Thread will wake up in pthread_join(), see the thread
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* it was joined to already detached and unlock itself
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*/
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} else {
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SEMAPHORE_RESET(lock);
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}
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}
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SEMAPHORE_RESET(plock);
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return(ret);
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}
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