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freebsd/lib/libc_r/uthread/uthread_resume_np.c
Jason Evans 314be1347b pthread_mutex_lock(), pthread_cond_trywait(), and pthread_cond_wait() are
not allowed to return EINTR, but use of pthread_suspend_np() could cause
EINTR to be returned.  To fix this, restructure pthread_suspend_np() so that
it does not interrupt a thread that is waiting on a mutex or condition, and
keep enough state around that pthread_resume_np() can fix things up
afterwards.

Reviewed by:	deischen
2000-06-14 17:17:41 +00:00

93 lines
3.1 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 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.
*
* $FreeBSD$
*/
#include <errno.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
/* Resume a thread: */
int
pthread_resume_np(pthread_t thread)
{
int ret;
enum pthread_susp old_suspended;
/* Find the thread in the list of active threads: */
if ((ret = _find_thread(thread)) == 0) {
/* Cancel any pending suspensions: */
old_suspended = thread->suspended;
thread->suspended = SUSP_NO;
/* Is it currently suspended? */
if (thread->state == PS_SUSPENDED) {
/*
* Defer signals to protect the scheduling queues
* from access by the signal handler:
*/
_thread_kern_sig_defer();
switch (old_suspended) {
case SUSP_MUTEX_WAIT:
/* Set the thread's state back. */
PTHREAD_SET_STATE(thread,PS_MUTEX_WAIT);
break;
case SUSP_COND_WAIT:
/* Set the thread's state back. */
PTHREAD_SET_STATE(thread,PS_COND_WAIT);
break;
case SUSP_NOWAIT:
/* Allow the thread to run. */
PTHREAD_SET_STATE(thread,PS_RUNNING);
PTHREAD_WAITQ_REMOVE(thread);
PTHREAD_PRIOQ_INSERT_TAIL(thread);
break;
case SUSP_NO:
case SUSP_YES:
/* Allow the thread to run. */
PTHREAD_SET_STATE(thread,PS_RUNNING);
PTHREAD_PRIOQ_INSERT_TAIL(thread);
break;
}
/*
* Undefer and handle pending signals, yielding if
* necessary:
*/
_thread_kern_sig_undefer();
}
}
return(ret);
}
#endif