freebsd-dev/lib/libthr/thread/thr_cancel.c
2006-04-04 02:57:49 +00:00

164 lines
4.4 KiB
C

/*
* Copyright (c) 2005, David Xu <davidxu@freebsd.org>
* 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 unmodified, 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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 "namespace.h"
#include <pthread.h>
#include "un-namespace.h"
#include "thr_private.h"
__weak_reference(_pthread_cancel, pthread_cancel);
__weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
__weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
__weak_reference(_pthread_testcancel, pthread_testcancel);
int
_pthread_cancel(pthread_t pthread)
{
struct pthread *curthread = _get_curthread();
int oldval, newval = 0;
int oldtype;
int ret;
/*
* POSIX says _pthread_cancel should be async cancellation safe,
* so we temporarily disable async cancellation.
*/
_pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
if ((ret = _thr_ref_add(curthread, pthread, 0)) != 0) {
_pthread_setcanceltype(oldtype, NULL);
return (ret);
}
do {
oldval = pthread->cancelflags;
if (oldval & THR_CANCEL_NEEDED)
break;
newval = oldval | THR_CANCEL_NEEDED;
} while (!atomic_cmpset_acq_int(&pthread->cancelflags, oldval, newval));
if (!(oldval & THR_CANCEL_NEEDED) && SHOULD_ASYNC_CANCEL(newval))
_thr_send_sig(pthread, SIGCANCEL);
_thr_ref_delete(curthread, pthread);
_pthread_setcanceltype(oldtype, NULL);
return (0);
}
static inline void
testcancel(struct pthread *curthread)
{
int newval;
newval = curthread->cancelflags;
if (SHOULD_CANCEL(newval) && !THR_IN_CRITICAL(curthread))
_pthread_exit(PTHREAD_CANCELED);
}
int
_pthread_setcancelstate(int state, int *oldstate)
{
struct pthread *curthread = _get_curthread();
int oldval, ret;
oldval = curthread->cancelflags;
if (oldstate != NULL)
*oldstate = ((oldval & THR_CANCEL_DISABLE) ?
PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
switch (state) {
case PTHREAD_CANCEL_DISABLE:
atomic_set_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
ret = 0;
break;
case PTHREAD_CANCEL_ENABLE:
atomic_clear_int(&curthread->cancelflags, THR_CANCEL_DISABLE);
testcancel(curthread);
ret = 0;
break;
default:
ret = EINVAL;
}
return (ret);
}
int
_pthread_setcanceltype(int type, int *oldtype)
{
struct pthread *curthread = _get_curthread();
int oldval, ret;
oldval = curthread->cancelflags;
if (oldtype != NULL)
*oldtype = ((oldval & THR_CANCEL_AT_POINT) ?
PTHREAD_CANCEL_ASYNCHRONOUS :
PTHREAD_CANCEL_DEFERRED);
switch (type) {
case PTHREAD_CANCEL_ASYNCHRONOUS:
atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
testcancel(curthread);
ret = 0;
break;
case PTHREAD_CANCEL_DEFERRED:
atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
ret = 0;
break;
default:
ret = EINVAL;
}
return (ret);
}
void
_pthread_testcancel(void)
{
testcancel(_get_curthread());
}
int
_thr_cancel_enter(struct pthread *curthread)
{
int oldval;
oldval = curthread->cancelflags;
if (!(oldval & THR_CANCEL_AT_POINT)) {
atomic_set_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
testcancel(curthread);
}
return (oldval);
}
void
_thr_cancel_leave(struct pthread *curthread, int previous)
{
if (!(previous & THR_CANCEL_AT_POINT))
atomic_clear_int(&curthread->cancelflags, THR_CANCEL_AT_POINT);
}