freebsd-skq/lib/libpthread/thread/thr_cancel.c
deischen cc69a08fbf Add compatibility symbol maps. libpthread (.so.1 and .so.2)
used LIBTHREAD_1_0 as its version definition, but now needs
to define its symbols in the same namespace used by libc.
The compatibility hooks allows you to use libraries and
binaries built and linked to libpthread before libc was
built with symbol versioning.  The shims can be removed if
libpthread is given a version bump.

Reviewed by:	davidxu
2006-03-13 00:59:51 +00:00

312 lines
7.8 KiB
C

/*
* David Leonard <d@openbsd.org>, 1999. Public domain.
* $FreeBSD$
*/
#include <sys/errno.h>
#include <pthread.h>
#include "thr_private.h"
LT10_COMPAT_PRIVATE(_pthread_cancel);
LT10_COMPAT_DEFAULT(pthread_cancel);
LT10_COMPAT_PRIVATE(_pthread_setcancelstate);
LT10_COMPAT_DEFAULT(pthread_setcancelstate);
LT10_COMPAT_PRIVATE(_pthread_setcanceltype);
LT10_COMPAT_DEFAULT(pthread_setcanceltype);
LT10_COMPAT_PRIVATE(_pthread_testcancel);
LT10_COMPAT_DEFAULT(pthread_testcancel);
__weak_reference(_pthread_cancel, pthread_cancel);
__weak_reference(_pthread_setcancelstate, pthread_setcancelstate);
__weak_reference(_pthread_setcanceltype, pthread_setcanceltype);
__weak_reference(_pthread_testcancel, pthread_testcancel);
static inline int
checkcancel(struct pthread *curthread)
{
if ((curthread->cancelflags & THR_CANCELLING) != 0) {
/*
* It is possible for this thread to be swapped out
* while performing cancellation; do not allow it
* to be cancelled again.
*/
if ((curthread->flags & THR_FLAGS_EXITING) != 0) {
/*
* This may happen once, but after this, it
* shouldn't happen again.
*/
curthread->cancelflags &= ~THR_CANCELLING;
return (0);
}
if ((curthread->cancelflags & PTHREAD_CANCEL_DISABLE) == 0) {
curthread->cancelflags &= ~THR_CANCELLING;
return (1);
}
}
return (0);
}
static inline void
testcancel(struct pthread *curthread)
{
if (checkcancel(curthread) != 0) {
/* Unlock before exiting: */
THR_THREAD_UNLOCK(curthread, curthread);
_thr_exit_cleanup();
pthread_exit(PTHREAD_CANCELED);
PANIC("cancel");
}
}
int
_pthread_cancel(pthread_t pthread)
{
struct pthread *curthread = _get_curthread();
struct pthread *joinee = NULL;
struct kse_mailbox *kmbx = NULL;
int ret;
if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/0)) == 0) {
/*
* Take the thread's lock while we change the cancel flags.
*/
THR_THREAD_LOCK(curthread, pthread);
THR_SCHED_LOCK(curthread, pthread);
if (pthread->flags & THR_FLAGS_EXITING) {
THR_SCHED_UNLOCK(curthread, pthread);
THR_THREAD_UNLOCK(curthread, pthread);
_thr_ref_delete(curthread, pthread);
return (ESRCH);
}
if (((pthread->cancelflags & PTHREAD_CANCEL_DISABLE) != 0) ||
(((pthread->cancelflags & THR_AT_CANCEL_POINT) == 0) &&
((pthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) == 0)))
/* Just mark it for cancellation: */
pthread->cancelflags |= THR_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 |= THR_CANCELLING;
break;
case PS_LOCKWAIT:
/*
* These can't be removed from the queue.
* Just mark it as cancelling and tell it
* to yield once it leaves the critical
* region.
*/
pthread->cancelflags |= THR_CANCELLING;
pthread->critical_yield = 1;
break;
case PS_SLEEP_WAIT:
case PS_SIGSUSPEND:
case PS_SIGWAIT:
/* Interrupt and resume: */
pthread->interrupted = 1;
pthread->cancelflags |= THR_CANCELLING;
kmbx = _thr_setrunnable_unlocked(pthread);
break;
case PS_JOIN:
/* Disconnect the thread from the joinee: */
joinee = pthread->join_status.thread;
pthread->join_status.thread = NULL;
pthread->cancelflags |= THR_CANCELLING;
kmbx = _thr_setrunnable_unlocked(pthread);
if ((joinee != NULL) &&
(pthread->kseg == joinee->kseg)) {
/* Remove the joiner from the joinee. */
joinee->joiner = NULL;
joinee = NULL;
}
break;
case PS_SUSPENDED:
case PS_MUTEX_WAIT:
case PS_COND_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 |= THR_CANCEL_NEEDED;
kmbx = _thr_setrunnable_unlocked(pthread);
pthread->continuation =
_thr_finish_cancellation;
break;
case PS_DEAD:
case PS_DEADLOCK:
case PS_STATE_MAX:
/* Ignore - only here to silence -Wall: */
break;
}
if ((pthread->cancelflags & THR_AT_CANCEL_POINT) &&
(pthread->blocked != 0 ||
pthread->attr.flags & PTHREAD_SCOPE_SYSTEM))
kse_thr_interrupt(&pthread->tcb->tcb_tmbx,
KSE_INTR_INTERRUPT, 0);
}
/*
* Release the thread's lock and remove the
* reference:
*/
THR_SCHED_UNLOCK(curthread, pthread);
THR_THREAD_UNLOCK(curthread, pthread);
_thr_ref_delete(curthread, pthread);
if (kmbx != NULL)
kse_wakeup(kmbx);
if ((joinee != NULL) &&
(_thr_ref_add(curthread, joinee, /* include dead */1) == 0)) {
/* Remove the joiner from the joinee. */
THR_SCHED_LOCK(curthread, joinee);
joinee->joiner = NULL;
THR_SCHED_UNLOCK(curthread, joinee);
_thr_ref_delete(curthread, joinee);
}
}
return (ret);
}
int
_pthread_setcancelstate(int state, int *oldstate)
{
struct pthread *curthread = _get_curthread();
int ostate;
int ret;
int need_exit = 0;
/* Take the thread's lock while fiddling with the state: */
THR_THREAD_LOCK(curthread, curthread);
ostate = curthread->cancelflags & PTHREAD_CANCEL_DISABLE;
switch (state) {
case PTHREAD_CANCEL_ENABLE:
curthread->cancelflags &= ~PTHREAD_CANCEL_DISABLE;
if ((curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0)
need_exit = checkcancel(curthread);
ret = 0;
break;
case PTHREAD_CANCEL_DISABLE:
curthread->cancelflags |= PTHREAD_CANCEL_DISABLE;
ret = 0;
break;
default:
ret = EINVAL;
}
THR_THREAD_UNLOCK(curthread, curthread);
if (need_exit != 0) {
_thr_exit_cleanup();
pthread_exit(PTHREAD_CANCELED);
PANIC("cancel");
}
if (ret == 0 && oldstate != NULL)
*oldstate = ostate;
return (ret);
}
int
_pthread_setcanceltype(int type, int *oldtype)
{
struct pthread *curthread = _get_curthread();
int otype;
int ret;
int need_exit = 0;
/* Take the thread's lock while fiddling with the state: */
THR_THREAD_LOCK(curthread, curthread);
otype = curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS;
switch (type) {
case PTHREAD_CANCEL_ASYNCHRONOUS:
curthread->cancelflags |= PTHREAD_CANCEL_ASYNCHRONOUS;
need_exit = checkcancel(curthread);
ret = 0;
break;
case PTHREAD_CANCEL_DEFERRED:
curthread->cancelflags &= ~PTHREAD_CANCEL_ASYNCHRONOUS;
ret = 0;
break;
default:
ret = EINVAL;
}
THR_THREAD_UNLOCK(curthread, curthread);
if (need_exit != 0) {
_thr_exit_cleanup();
pthread_exit(PTHREAD_CANCELED);
PANIC("cancel");
}
if (ret == 0 && oldtype != NULL)
*oldtype = otype;
return (ret);
}
void
_pthread_testcancel(void)
{
struct pthread *curthread = _get_curthread();
THR_THREAD_LOCK(curthread, curthread);
testcancel(curthread);
THR_THREAD_UNLOCK(curthread, curthread);
}
void
_thr_cancel_enter(struct pthread *thread)
{
/* Look for a cancellation before we block: */
THR_THREAD_LOCK(thread, thread);
testcancel(thread);
thread->cancelflags |= THR_AT_CANCEL_POINT;
THR_THREAD_UNLOCK(thread, thread);
}
void
_thr_cancel_leave(struct pthread *thread, int check)
{
THR_THREAD_LOCK(thread, thread);
thread->cancelflags &= ~THR_AT_CANCEL_POINT;
/* Look for a cancellation after we unblock: */
if (check)
testcancel(thread);
THR_THREAD_UNLOCK(thread, thread);
}
void
_thr_finish_cancellation(void *arg)
{
struct pthread *curthread = _get_curthread();
curthread->continuation = NULL;
curthread->interrupted = 0;
THR_THREAD_LOCK(curthread, curthread);
if ((curthread->cancelflags & THR_CANCEL_NEEDED) != 0) {
curthread->cancelflags &= ~THR_CANCEL_NEEDED;
THR_THREAD_UNLOCK(curthread, curthread);
_thr_exit_cleanup();
pthread_exit(PTHREAD_CANCELED);
}
THR_THREAD_UNLOCK(curthread, curthread);
}