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/* ==== pthread_join.c =======================================================
* Copyright (c) 1994 by Chris Provenzano, proven@mit.edu
* 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 Chris Provenzano.
* 4. The name of Chris Provenzano may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY CHRIS PROVENZANO ``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 CHRIS PROVENZANO 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.
*
* Description : pthread_join function.
*
* 1.00 94/01/15 proven
* -Started coding this file.
*/
#ifndef lint
static const char rcsid[] = "$Id: pthread_join.c,v 1.1 1995/10/18 08:43:05 deraadt Exp $ $provenid: pthread_join.c,v 1.16 1994/02/07 02:19:19 proven Exp $";
#endif
#include <pthread.h>
/* ==========================================================================
* pthread_join()
*/
int pthread_join(pthread_t pthread, void **thread_return)
{
semaphore *lock, *plock;
int ret;
plock = &(pthread->lock);
while (SEMAPHORE_TEST_AND_SET(plock)) {
pthread_yield();
}
/* Check that thread isn't detached already */
if (pthread->flags & PF_DETACHED) {
SEMAPHORE_RESET(plock);
return(ESRCH);
}
lock = &(pthread_run->lock);
while (SEMAPHORE_TEST_AND_SET(lock)) {
pthread_yield();
}
/* If OK then queue current thread. */
pthread_queue(&(pthread->join_queue), pthread_run);
SEMAPHORE_RESET(plock);
reschedule(PS_JOIN);
/*
* At this point the thread is locked from the pthread_exit
* and so are we, so no extra locking is required, but be sure
* to unlock at least ourself.
*/
if (!(pthread->flags & PF_DETACHED)) {
if (thread_return) {
*thread_return = pthread->ret;
}
pthread->flags |= PF_DETACHED;
ret = OK;
} else {
ret = ESRCH;
}
/* Cant do a cleanup until queue is cleared */
{
struct pthread * next_thread;
semaphore * next_lock;
if (next_thread = pthread_queue_get(&(pthread->join_queue))) {
next_lock = &(next_thread->lock);
while (SEMAPHORE_TEST_AND_SET(next_lock)) {
pthread_yield();
}
pthread_queue_deq(&(pthread->join_queue));
next_thread->state = PS_RUNNING;
/*
* Thread will wake up in pthread_join(), see the thread
* it was joined to already detached and unlock itself
*/
} else {
SEMAPHORE_RESET(lock);
}
}
SEMAPHORE_RESET(plock);
return(ret);
}
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