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/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 1995-1998 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. 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 AUTHOR 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <errno.h>
#include <pthread.h>
#include <pthread_np.h>
#include "un-namespace.h"
#include "thr_private.h"
static int suspend_common(struct pthread *, struct pthread *,
int);
__weak_reference(_pthread_suspend_np, pthread_suspend_np);
__weak_reference(_pthread_suspend_all_np, pthread_suspend_all_np);
/* Suspend a thread: */
int
_pthread_suspend_np(pthread_t thread)
{
struct pthread *curthread = _get_curthread();
int ret;
/* Suspending the current thread doesn't make sense. */
if (thread == _get_curthread())
ret = EDEADLK;
/* Add a reference to the thread: */
else if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0))
== 0) {
/* Lock the threads scheduling queue: */
THR_THREAD_LOCK(curthread, thread);
suspend_common(curthread, thread, 1);
/* Unlock the threads scheduling queue: */
THR_THREAD_UNLOCK(curthread, thread);
/* Don't forget to remove the reference: */
_thr_ref_delete(curthread, thread);
}
return (ret);
}
void
_thr_suspend_all_lock(struct pthread *curthread)
{
int old;
THR_LOCK_ACQUIRE(curthread, &_suspend_all_lock);
while (_single_thread != NULL) {
old = _suspend_all_cycle;
_suspend_all_waiters++;
THR_LOCK_RELEASE(curthread, &_suspend_all_lock);
_thr_umtx_wait_uint(&_suspend_all_cycle, old, NULL, 0);
THR_LOCK_ACQUIRE(curthread, &_suspend_all_lock);
_suspend_all_waiters--;
}
_single_thread = curthread;
THR_LOCK_RELEASE(curthread, &_suspend_all_lock);
}
void
_thr_suspend_all_unlock(struct pthread *curthread)
{
THR_LOCK_ACQUIRE(curthread, &_suspend_all_lock);
_single_thread = NULL;
if (_suspend_all_waiters != 0) {
_suspend_all_cycle++;
_thr_umtx_wake(&_suspend_all_cycle, INT_MAX, 0);
}
THR_LOCK_RELEASE(curthread, &_suspend_all_lock);
}
void
_pthread_suspend_all_np(void)
{
struct pthread *curthread = _get_curthread();
struct pthread *thread;
int old_nocancel;
int ret;
old_nocancel = curthread->no_cancel;
curthread->no_cancel = 1;
_thr_suspend_all_lock(curthread);
THREAD_LIST_RDLOCK(curthread);
TAILQ_FOREACH(thread, &_thread_list, tle) {
if (thread != curthread) {
THR_THREAD_LOCK(curthread, thread);
if (thread->state != PS_DEAD &&
!(thread->flags & THR_FLAGS_SUSPENDED))
thread->flags |= THR_FLAGS_NEED_SUSPEND;
THR_THREAD_UNLOCK(curthread, thread);
}
}
thr_kill(-1, SIGCANCEL);
restart:
TAILQ_FOREACH(thread, &_thread_list, tle) {
if (thread != curthread) {
/* First try to suspend the thread without waiting */
THR_THREAD_LOCK(curthread, thread);
ret = suspend_common(curthread, thread, 0);
if (ret == 0) {
THREAD_LIST_UNLOCK(curthread);
/* Can not suspend, try to wait */
THR_REF_ADD(curthread, thread);
suspend_common(curthread, thread, 1);
THR_REF_DEL(curthread, thread);
_thr_try_gc(curthread, thread);
/* thread lock released */
THREAD_LIST_RDLOCK(curthread);
/*
* Because we were blocked, things may have
* been changed, we have to restart the
* process.
*/
goto restart;
}
THR_THREAD_UNLOCK(curthread, thread);
}
}
THREAD_LIST_UNLOCK(curthread);
_thr_suspend_all_unlock(curthread);
curthread->no_cancel = old_nocancel;
_thr_testcancel(curthread);
}
static int
suspend_common(struct pthread *curthread, struct pthread *thread,
int waitok)
{
uint32_t tmp;
while (thread->state != PS_DEAD &&
!(thread->flags & THR_FLAGS_SUSPENDED)) {
thread->flags |= THR_FLAGS_NEED_SUSPEND;
/* Thread is in creation. */
if (thread->tid == TID_TERMINATED)
return (1);
tmp = thread->cycle;
_thr_send_sig(thread, SIGCANCEL);
THR_THREAD_UNLOCK(curthread, thread);
if (waitok) {
_thr_umtx_wait_uint(&thread->cycle, tmp, NULL, 0);
THR_THREAD_LOCK(curthread, thread);
} else {
THR_THREAD_LOCK(curthread, thread);
return (0);
}
}
return (1);
}
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