/*
* Internal routine to terminate a thread.
* Sometimes called with task already locked.
*/
kern_return_t
thread_terminate_internal(
thread_t thread)
{
kern_return_t result = KERN_SUCCESS;
thread_mtx_lock(thread);
if (thread->active) {
thread->active = FALSE;
act_abort(thread);
if (thread->started)
clear_wait(thread, THREAD_INTERRUPTED);
else {
thread_start_internal(thread);
}
}
else
result = KERN_TERMINATED;
if (thread->affinity_set != NULL)
thread_affinity_terminate(thread);
thread_mtx_unlock(thread);
if (thread != current_thread() && result == KERN_SUCCESS)
thread_wait(thread, FALSE);
return (result);
}
/*
* Internal routine to mark a thread as started.
* Always called with the thread mutex locked.
*/
void
thread_start(
thread_t thread)
{
clear_wait(thread, THREAD_AWAKENED);
thread->started = TRUE;
}
/*
* Internal routine to mark a thread as started.
* Always called with the thread locked.
*
* Note: function intentionally declared with the noinline attribute to
* prevent multiple declaration of probe symbols in this file; we would
* prefer "#pragma noinline", but gcc does not support it.
* PR-6385749 -- the lwp-start probe should fire from within the context
* of the newly created thread. Commented out for now, in case we
* turn it into a dead code probe.
*/
void
thread_start_internal(
thread_t thread)
{
clear_wait(thread, THREAD_AWAKENED);
thread->started = TRUE;
// DTRACE_PROC1(lwp__start, thread_t, thread);
}
/*
* Decrement internal suspension count for thr_act, setting thread
* runnable when count falls to zero.
*
* Called with act_lock held.
*/
void
thread_release(
register thread_act_t act)
{
thread_t thread = act->thread;
if ( act->suspend_count > 0 &&
--act->suspend_count == 0 &&
thread != THREAD_NULL &&
thread->top_act == act ) {
if (!act->started) {
clear_wait(thread, THREAD_AWAKENED);
act->started = TRUE;
}
else
thread_wakeup_one(&act->suspend_count);
}
}
kern_return_t
thread_abort(
register thread_t thread)
{
kern_return_t result = KERN_SUCCESS;
if (thread == THREAD_NULL)
return (KERN_INVALID_ARGUMENT);
thread_mtx_lock(thread);
if (thread->active) {
act_abort(thread);
clear_wait(thread, THREAD_INTERRUPTED);
}
else
result = KERN_TERMINATED;
thread_mtx_unlock(thread);
return (result);
}
/*
* Internal routine to terminate a thread.
* Sometimes called with task already locked.
*/
kern_return_t
thread_terminate_internal(
register thread_act_t act)
{
kern_return_t result;
thread_t thread;
thread = act_lock_thread(act);
if (!act->active) {
act_unlock_thread(act);
return (KERN_TERMINATED);
}
act_disable(act);
result = act_abort(act, FALSE);
/*
* Make sure this thread enters the kernel
* Must unlock the act, but leave the shuttle
* captured in this act.
*/
if (thread != current_thread()) {
act_unlock(act);
if (thread_stop(thread))
thread_unstop(thread);
else
result = KERN_ABORTED;
act_lock(act);
}
clear_wait(thread, act->started? THREAD_INTERRUPTED: THREAD_AWAKENED);
act_unlock_thread(act);
return (result);
}
kern_return_t
thread_abort(
register thread_act_t act)
{
kern_return_t result;
thread_t thread;
if (act == THR_ACT_NULL)
return (KERN_INVALID_ARGUMENT);
thread = act_lock_thread(act);
if (!act->active) {
act_unlock_thread(act);
return (KERN_TERMINATED);
}
result = act_abort(act, FALSE);
clear_wait(thread, THREAD_INTERRUPTED);
act_unlock_thread(act);
return (result);
}
kern_return_t
thread_resume(
register thread_act_t act)
{
kern_return_t result = KERN_SUCCESS;
thread_t thread;
if (act == THR_ACT_NULL || act->task == kernel_task)
return (KERN_INVALID_ARGUMENT);
thread = act_lock_thread(act);
if (act->active) {
if (act->user_stop_count > 0) {
if ( --act->user_stop_count == 0 &&
--act->suspend_count == 0 &&
thread != THREAD_NULL &&
thread->top_act == act ) {
if (!act->started) {
clear_wait(thread, THREAD_AWAKENED);
act->started = TRUE;
}
else
thread_wakeup_one(&act->suspend_count);
}
}
else
result = KERN_FAILURE;
}
else
result = KERN_TERMINATED;
act_unlock_thread(act);
return (result);
}
/*
* Routine: semaphore_wait_internal
*
* Decrements the semaphore count by one. If the count is
* negative after the decrement, the calling thread blocks
* (possibly at a continuation and/or with a timeout).
*
* Assumptions:
* The reference
* A reference is held on the signal semaphore.
*/
kern_return_t
semaphore_wait_internal(
semaphore_t wait_semaphore,
semaphore_t signal_semaphore,
mach_timespec_t *wait_timep,
void (*caller_cont)(kern_return_t))
{
boolean_t nonblocking;
int wait_result;
spl_t spl_level;
kern_return_t kr = KERN_ALREADY_WAITING;
spl_level = splsched();
semaphore_lock(wait_semaphore);
/*
* Decide if we really have to wait.
*/
nonblocking = (wait_timep != (mach_timespec_t *)0) ?
(wait_timep->tv_sec == 0 && wait_timep->tv_nsec == 0) :
FALSE;
if (!wait_semaphore->active) {
kr = KERN_TERMINATED;
} else if (wait_semaphore->count > 0) {
wait_semaphore->count--;
kr = KERN_SUCCESS;
} else if (nonblocking) {
kr = KERN_OPERATION_TIMED_OUT;
} else {
uint64_t abstime;
thread_t self = current_thread();
wait_semaphore->count = -1; /* we don't keep an actual count */
thread_lock(self);
/*
* If it is a timed wait, calculate the wake up deadline.
*/
if (wait_timep != (mach_timespec_t *)0) {
nanoseconds_to_absolutetime((uint64_t)wait_timep->tv_sec *
NSEC_PER_SEC + wait_timep->tv_nsec, &abstime);
clock_absolutetime_interval_to_deadline(abstime, &abstime);
}
else
abstime = 0;
(void)wait_queue_assert_wait64_locked(
&wait_semaphore->wait_queue,
SEMAPHORE_EVENT,
THREAD_ABORTSAFE, abstime,
self);
thread_unlock(self);
}
semaphore_unlock(wait_semaphore);
splx(spl_level);
/*
* wait_semaphore is unlocked so we are free to go ahead and
* signal the signal_semaphore (if one was provided).
*/
if (signal_semaphore != SEMAPHORE_NULL) {
kern_return_t signal_kr;
/*
* lock the signal semaphore reference we got and signal it.
* This will NOT block (we cannot block after having asserted
* our intention to wait above).
*/
signal_kr = semaphore_signal_internal(signal_semaphore,
THREAD_NULL,
SEMAPHORE_SIGNAL_PREPOST);
if (signal_kr == KERN_NOT_WAITING)
signal_kr = KERN_SUCCESS;
else if (signal_kr == KERN_TERMINATED) {
/*
* Uh!Oh! The semaphore we were to signal died.
* We have to get ourselves out of the wait in
* case we get stuck here forever (it is assumed
* that the semaphore we were posting is gating
* the decision by someone else to post the
* semaphore we are waiting on). People will
* discover the other dead semaphore soon enough.
* If we got out of the wait cleanly (someone
* already posted a wakeup to us) then return that
* (most important) result. Otherwise,
* return the KERN_TERMINATED status.
*/
thread_t self = current_thread();
clear_wait(self, THREAD_INTERRUPTED);
kr = semaphore_convert_wait_result(self->wait_result);
if (kr == KERN_ABORTED)
kr = KERN_TERMINATED;
}
}
/*
* If we had an error, or we didn't really need to wait we can
* return now that we have signalled the signal semaphore.
*/
if (kr != KERN_ALREADY_WAITING)
return kr;
/*
* Now, we can block. If the caller supplied a continuation
* pointer of his own for after the block, block with the
* appropriate semaphore continuation. Thiswill gather the
* semaphore results, release references on the semaphore(s),
* and then call the caller's continuation.
*/
if (caller_cont) {
thread_t self = current_thread();
self->sth_continuation = caller_cont;
self->sth_waitsemaphore = wait_semaphore;
self->sth_signalsemaphore = signal_semaphore;
wait_result = thread_block((thread_continue_t)semaphore_wait_continue);
}
else {
wait_result = thread_block(THREAD_CONTINUE_NULL);
}
return (semaphore_convert_wait_result(wait_result));
}
