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/* $OpenBSD: uthread_cancel.c,v 1.13 2002/05/07 05:13:17 pvalchev Exp $ */
/*
* David Leonard <d@openbsd.org>, 1999. Public domain.
*/
#include <sys/errno.h>
#include <pthread.h>
#include "pthread_private.h"
static void finish_cancellation(void *arg);
int
pthread_cancel(pthread_t pthread)
{
int ret;
if ((ret = _find_thread(pthread)) != 0) {
/* NOTHING */
} else if (pthread->state == PS_DEAD || pthread->state == PS_DEADLOCK
|| (pthread->flags & PTHREAD_EXITING) != 0) {
ret = 0;
} else {
/* Protect the scheduling queues: */
_thread_kern_sig_defer();
if (((pthread->cancelflags & PTHREAD_CANCEL_DISABLE) != 0) ||
(((pthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) == 0) &&
((pthread->cancelflags & PTHREAD_AT_CANCEL_POINT) == 0)))
/* Just mark it for cancellation: */
pthread->cancelflags |= PTHREAD_CANCELLING;
else {
/*
* Check if we need to kick it back into the
* run queue:
*/
switch (pthread->state) {
case PS_RUNNING:
/* No need to resume: */
pthread->cancelflags |= PTHREAD_CANCELLING;
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: */
if ((pthread->flags & PTHREAD_FLAGS_IN_WORKQ)
!= 0)
PTHREAD_WORKQ_REMOVE(pthread);
/* Fall through: */
case PS_SIGTHREAD:
case PS_SLEEP_WAIT:
case PS_WAIT_WAIT:
case PS_SIGSUSPEND:
case PS_SIGWAIT:
/* Interrupt and resume: */
pthread->interrupted = 1;
pthread->cancelflags |= PTHREAD_CANCELLING;
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
break;
case PS_JOIN:
/*
* Disconnect the thread from the joinee:
*/
if (pthread->join_status.thread != NULL) {
pthread->join_status.thread->joiner
= NULL;
pthread->join_status.thread = NULL;
}
pthread->cancelflags |= PTHREAD_CANCELLING;
PTHREAD_NEW_STATE(pthread, PS_RUNNING);
break;
case PS_SUSPENDED:
if (pthread->suspended == SUSP_NO ||
pthread->suspended == SUSP_YES ||
pthread->suspended == SUSP_JOIN ||
pthread->suspended == SUSP_NOWAIT) {
/*
* This thread isn't in any scheduling
* queues; just change it's state:
*/
pthread->cancelflags |=
PTHREAD_CANCELLING;
PTHREAD_SET_STATE(pthread, PS_RUNNING);
break;
}
/* FALLTHROUGH */
case PS_MUTEX_WAIT:
case PS_COND_WAIT:
case PS_FDLR_WAIT:
case PS_FDLW_WAIT:
case PS_FILE_WAIT:
/*
* 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
* needing cancellation, and set the state to
* running. When the thread resumes, it will
* remove itself from the queue and call the
* cancellation completion routine.
*/
pthread->interrupted = 1;
pthread->cancelflags |= PTHREAD_CANCEL_NEEDED;
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
pthread->continuation = finish_cancellation;
break;
case PS_DEAD:
case PS_DEADLOCK:
case PS_STATE_MAX:
/* Ignore - only here to silence -Wall: */
break;
}
}
/* Unprotect the scheduling queues: */
_thread_kern_sig_undefer();
ret = 0;
}
return (ret);
}
int
pthread_setcancelstate(int state, int *oldstate)
{
struct pthread *curthread = _get_curthread();
int ostate;
int ret;
ostate = curthread->cancelflags & PTHREAD_CANCEL_DISABLE;
switch (state) {
case PTHREAD_CANCEL_ENABLE:
if (oldstate != NULL)
*oldstate = ostate;
curthread->cancelflags &= ~PTHREAD_CANCEL_DISABLE;
if ((curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0)
pthread_testcancel();
ret = 0;
break;
case PTHREAD_CANCEL_DISABLE:
if (oldstate != NULL)
*oldstate = ostate;
curthread->cancelflags |= PTHREAD_CANCEL_DISABLE;
ret = 0;
break;
default:
ret = EINVAL;
}
return (ret);
}
int
pthread_setcanceltype(int type, int *oldtype)
{
struct pthread *curthread = _get_curthread();
int otype;
int ret;
otype = curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS;
switch (type) {
case PTHREAD_CANCEL_ASYNCHRONOUS:
if (oldtype != NULL)
*oldtype = otype;
curthread->cancelflags |= PTHREAD_CANCEL_ASYNCHRONOUS;
pthread_testcancel();
ret = 0;
break;
case PTHREAD_CANCEL_DEFERRED:
if (oldtype != NULL)
*oldtype = otype;
curthread->cancelflags &= ~PTHREAD_CANCEL_ASYNCHRONOUS;
ret = 0;
break;
default:
ret = EINVAL;
}
return (ret);
}
void
pthread_testcancel(void)
{
struct pthread *curthread = _get_curthread();
if (((curthread->cancelflags & PTHREAD_CANCEL_DISABLE) == 0) &&
((curthread->cancelflags & PTHREAD_CANCELLING) != 0) &&
((curthread->flags & PTHREAD_EXITING) == 0)) {
/*
* It is possible for this thread to be swapped out
* while performing cancellation; do not allow it
* to be cancelled again.
*/
curthread->cancelflags &= ~PTHREAD_CANCELLING;
#ifdef notyet
_thread_exit_cleanup();
#endif
pthread_exit(PTHREAD_CANCELED);
PANIC("cancel");
}
}
void
_thread_enter_cancellation_point(void)
{
struct pthread *curthread = _get_curthread();
/* Look for a cancellation before we block: */
pthread_testcancel();
curthread->cancelflags |= PTHREAD_AT_CANCEL_POINT;
}
void
_thread_leave_cancellation_point(void)
{
struct pthread *curthread = _get_curthread();
curthread->cancelflags &= ~PTHREAD_AT_CANCEL_POINT;
/* Look for a cancellation after we unblock: */
pthread_testcancel();
}
static void
finish_cancellation(void *arg)
{
struct pthread *curthread = _get_curthread();
curthread->continuation = NULL;
curthread->interrupted = 0;
if ((curthread->cancelflags & PTHREAD_CANCEL_NEEDED) != 0) {
curthread->cancelflags &= ~PTHREAD_CANCEL_NEEDED;
#ifdef notyet
_thread_exit_cleanup();
#endif
pthread_exit(PTHREAD_CANCELED);
}
}
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