void
_thr_gc(struct pthread *curthread)
{
struct pthread *td, *td_next;
TAILQ_HEAD(, pthread) worklist;
TAILQ_INIT(&worklist);
THREAD_LIST_LOCK(curthread);
/* Check the threads waiting for GC. */
for (td = TAILQ_FIRST(&_thread_gc_list); td != NULL; td = td_next) {
td_next = TAILQ_NEXT(td, gcle);
if (td->terminated == 0) {
/* make sure we are not still in userland */
continue;
}
_thr_stack_free(&td->attr);
if (((td->tlflags & TLFLAGS_DETACHED) != 0) &&
(td->refcount == 0)) {
THR_GCLIST_REMOVE(td);
/*
* The thread has detached and is no longer
* referenced. It is safe to remove all
* remnants of the thread.
*/
THR_LIST_REMOVE(td);
TAILQ_INSERT_HEAD(&worklist, td, gcle);
}
}
THREAD_LIST_UNLOCK(curthread);
while ((td = TAILQ_FIRST(&worklist)) != NULL) {
TAILQ_REMOVE(&worklist, td, gcle);
/*
* XXX we don't free initial thread, because there might
* have some code referencing initial thread.
*/
if (td == _thr_initial) {
DBG_MSG("Initial thread won't be freed\n");
continue;
}
_thr_free(curthread, td);
}
}
int
_pthread_join(pthread_t pthread, void **thread_return)
{
struct pthread *curthread = _get_curthread();
void *tmp;
kse_critical_t crit;
int ret = 0;
_thr_cancel_enter(curthread);
/* Check if the caller has specified an invalid thread: */
if (pthread == NULL || pthread->magic != THR_MAGIC) {
/* Invalid thread: */
_thr_cancel_leave(curthread, 1);
return (EINVAL);
}
/* Check if the caller has specified itself: */
if (pthread == curthread) {
/* Avoid a deadlock condition: */
_thr_cancel_leave(curthread, 1);
return (EDEADLK);
}
/*
* Find the thread in the list of active threads or in the
* list of dead threads:
*/
if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/1)) != 0) {
/* Return an error: */
_thr_cancel_leave(curthread, 1);
return (ESRCH);
}
THR_SCHED_LOCK(curthread, pthread);
/* Check if this thread has been detached: */
if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
THR_SCHED_UNLOCK(curthread, pthread);
/* Remove the reference and return an error: */
_thr_ref_delete(curthread, pthread);
ret = EINVAL;
} else {
/* Lock the target thread while checking its state. */
if (pthread->state == PS_DEAD) {
/* Return the thread's return value: */
tmp = pthread->ret;
/* Detach the thread. */
pthread->attr.flags |= PTHREAD_DETACHED;
/* Unlock the thread. */
THR_SCHED_UNLOCK(curthread, pthread);
/*
* Remove the thread from the list of active
* threads and add it to the GC list.
*/
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
THR_LIST_REMOVE(pthread);
THR_GCLIST_ADD(pthread);
KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
_kse_critical_leave(crit);
/* Remove the reference. */
_thr_ref_delete(curthread, pthread);
if (thread_return != NULL)
*thread_return = tmp;
}
else if (pthread->joiner != NULL) {
/* Unlock the thread and remove the reference. */
THR_SCHED_UNLOCK(curthread, pthread);
_thr_ref_delete(curthread, pthread);
/* Multiple joiners are not supported. */
ret = ENOTSUP;
}
else {
/* Set the running thread to be the joiner: */
pthread->joiner = curthread;
/* Keep track of which thread we're joining to: */
curthread->join_status.thread = pthread;
/* Unlock the thread and remove the reference. */
THR_SCHED_UNLOCK(curthread, pthread);
_thr_ref_delete(curthread, pthread);
THR_SCHED_LOCK(curthread, curthread);
while (curthread->join_status.thread == pthread) {
THR_SET_STATE(curthread, PS_JOIN);
THR_SCHED_UNLOCK(curthread, curthread);
/* Schedule the next thread: */
_thr_sched_switch(curthread);
THR_SCHED_LOCK(curthread, curthread);
}
THR_SCHED_UNLOCK(curthread, curthread);
if ((curthread->cancelflags & THR_CANCELLING) &&
!(curthread->cancelflags & PTHREAD_CANCEL_DISABLE)) {
if (_thr_ref_add(curthread, pthread, 1) == 0) {
THR_SCHED_LOCK(curthread, pthread);
pthread->joiner = NULL;
THR_SCHED_UNLOCK(curthread, pthread);
_thr_ref_delete(curthread, pthread);
}
_pthread_exit(PTHREAD_CANCELED);
}
/*
* The thread return value and error are set by the
* thread we're joining to when it exits or detaches:
*/
ret = curthread->join_status.error;
if ((ret == 0) && (thread_return != NULL))
*thread_return = curthread->join_status.ret;
}
}
_thr_cancel_leave(curthread, 1);
/* Return the completion status: */
return (ret);
}