freebsd-dev/lib/libc_r/uthread/uthread_suspend_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

153 lines
4.5 KiB
C

/*
* 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. 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"
static void finish_suspension(void *arg);
/* Suspend a thread: */
int
pthread_suspend_np(pthread_t thread)
{
int ret;
/* Find the thread in the list of active threads: */
if ((ret = _find_thread(thread)) == 0) {
/*
* Defer signals to protect the scheduling queues from
* access by the signal handler:
*/
_thread_kern_sig_defer();
switch (thread->state) {
case PS_RUNNING:
/*
* Remove the thread from the priority queue and
* set the state to suspended:
*/
PTHREAD_PRIOQ_REMOVE(thread);
PTHREAD_SET_STATE(thread, PS_SUSPENDED);
break;
case PS_SPINBLOCK:
case PS_FDR_WAIT:
case PS_FDW_WAIT:
case PS_POLL_WAIT:
case PS_SELECT_WAIT:
/*
* Remove these threads from the work queue
* and mark the operation as interrupted:
*/
if ((thread->flags & PTHREAD_FLAGS_IN_WORKQ) != 0)
PTHREAD_WORKQ_REMOVE(thread);
_thread_seterrno(thread,EINTR);
thread->interrupted = 1;
/* FALLTHROUGH */
case PS_SIGTHREAD:
case PS_SLEEP_WAIT:
case PS_WAIT_WAIT:
case PS_SIGSUSPEND:
case PS_SIGWAIT:
/*
* Remove these threads from the waiting queue and
* set their state to suspended:
*/
PTHREAD_WAITQ_REMOVE(thread);
PTHREAD_SET_STATE(thread, PS_SUSPENDED);
break;
case PS_MUTEX_WAIT:
/* Mark the thread as suspended and still in a queue. */
thread->suspended = SUSP_MUTEX_WAIT;
PTHREAD_SET_STATE(thread, PS_SUSPENDED);
break;
case PS_COND_WAIT:
/* Mark the thread as suspended and still in a queue. */
thread->suspended = SUSP_COND_WAIT;
PTHREAD_SET_STATE(thread, PS_SUSPENDED);
break;
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_FILE_WAIT:
case PS_JOIN:
/* Mark the thread as suspended: */
thread->suspended = SUSP_YES;
/*
* Threads in these states may be in queues.
* In order to preserve queue integrity, the
* cancelled thread must remove itself from the
* queue. Mark the thread as interrupted and
* set the state to running. When the thread
* resumes, it will remove itself from the queue
* and call the suspension completion routine.
*/
thread->interrupted = 1;
_thread_seterrno(thread, EINTR);
PTHREAD_NEW_STATE(thread, PS_RUNNING);
thread->continuation = finish_suspension;
break;
case PS_DEAD:
case PS_DEADLOCK:
case PS_STATE_MAX:
case PS_SUSPENDED:
/* Nothing needs to be done: */
break;
}
/*
* Undefer and handle pending signals, yielding if
* necessary:
*/
_thread_kern_sig_undefer();
}
return(ret);
}
static void
finish_suspension(void *arg)
{
if (_thread_run->suspended != SUSP_NO)
_thread_kern_sched_state(PS_SUSPENDED, __FILE__, __LINE__);
}
#endif