freebsd-dev/lib/libc_r/uthread/uthread_join.c
John Birrell ed92686917 Add a magic field to the pthread structure to help recognize valid
threads from invalid ones. The pthread structure is opaque to the user
so this change does not cause any incompatibilities.

Hopefully this change will help code that was written for draft 4
fail gracefully if the programmer ignores the compiler warning about
the change in the level of indirection for the argument passed to
pthread_detach(). I got burnt, so I fixed then (expletive deleted)
thing.

These functions comply with the revised standard. That should shut
Terry up!
1998-04-03 09:31:15 +00:00

124 lines
3.9 KiB
C

/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* 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 John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 THE REGENTS OR CONTRIBUTORS 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.
*
*/
#include <errno.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
pthread_join(pthread_t pthread, void **thread_return)
{
int rval = 0;
int status;
pthread_t pthread1;
/* Check if the caller has specified an invalid thread: */
if (pthread == NULL || pthread->magic != PTHREAD_MAGIC)
/* Invalid thread: */
return(EINVAL);
/* Check if the caller has specified itself: */
if (pthread == _thread_run)
/* Avoid a deadlock condition: */
return(EDEADLK);
/* Block signals: */
_thread_kern_sig_block(&status);
/* Point to the first thread in the list: */
pthread1 = _thread_link_list;
/* Search for the thread to join to: */
while (pthread1 != NULL && pthread1 != pthread) {
/* Point to the next thread: */
pthread1 = pthread1->nxt;
}
if (pthread1 == NULL) {
/* Point to the first thread in the dead thread list: */
pthread1 = _thread_dead;
/* Search for the thread to join to: */
while (pthread1 != NULL && pthread1 != pthread) {
/* Point to the next thread: */
pthread1 = pthread1->nxt;
}
}
if (pthread1 == NULL) {
/* Return an error: */
rval = ESRCH;
/* Check if this thread has been detached: */
} else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
/* Return an error: */
rval = ESRCH;
}
/* Check if the thread is not dead: */
else if (pthread->state != PS_DEAD) {
/* Add the running thread to the join queue: */
_thread_queue_enq(&(pthread->join_queue), _thread_run);
/* Schedule the next thread: */
_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
/* Block signals again: */
_thread_kern_sig_block(NULL);
/* Check if the thread is not detached: */
if ((pthread->attr.flags & PTHREAD_DETACHED) == 0) {
/* Check if the return value is required: */
if (thread_return) {
/* Return the thread's return value: */
*thread_return = pthread->ret;
}
} else {
/* Return an error: */
rval = ESRCH;
}
} else {
/* Check if the return value is required: */
if (thread_return != NULL) {
/* Return the thread's return value: */
*thread_return = pthread->ret;
}
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
#endif