void
mutex_pause(void)
{
thread_will_wait_with_timeout (current_thread(), 1);
ETAP_SET_REASON(current_thread(), BLOCKED_ON_MUTEX_LOCK);
thread_block (0);
}
mach_msg_return_t
ipc_mqueue_receive(
ipc_mqueue_t mqueue,
mach_msg_option_t option,
mach_msg_size_t max_size,
mach_msg_timeout_t time_out,
boolean_t resume,
void (*continuation)(void),
ipc_kmsg_t *kmsgp,
mach_port_seqno_t *seqnop)
{
ipc_port_t port;
ipc_kmsg_t kmsg;
mach_port_seqno_t seqno;
{
ipc_kmsg_queue_t kmsgs = &mqueue->imq_messages;
ipc_thread_t self = current_thread();
if (resume)
goto after_thread_block;
for (;;) {
kmsg = ipc_kmsg_queue_first(kmsgs);
if (kmsg != IKM_NULL) {
/* check space requirements */
if (kmsg->ikm_header.msgh_size > max_size) {
* (mach_msg_size_t *) kmsgp =
kmsg->ikm_header.msgh_size;
imq_unlock(mqueue);
return MACH_RCV_TOO_LARGE;
}
ipc_kmsg_rmqueue_first_macro(kmsgs, kmsg);
port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port;
seqno = port->ip_seqno++;
break;
}
/* must block waiting for a message */
if (option & MACH_RCV_TIMEOUT) {
if (time_out == 0) {
imq_unlock(mqueue);
return MACH_RCV_TIMED_OUT;
}
thread_will_wait_with_timeout(self, time_out);
} else
thread_will_wait(self);
ipc_thread_enqueue_macro(&mqueue->imq_threads, self);
self->ith_state = MACH_RCV_IN_PROGRESS;
self->ith_msize = max_size;
imq_unlock(mqueue);
if (continuation != (void (*)(void)) 0) {
counter(c_ipc_mqueue_receive_block_user++);
} else {
counter(c_ipc_mqueue_receive_block_kernel++);
}
thread_block(continuation);
after_thread_block:
imq_lock(mqueue);
/* why did we wake up? */
if (self->ith_state == MACH_MSG_SUCCESS) {
/* pick up the message that was handed to us */
kmsg = self->ith_kmsg;
seqno = self->ith_seqno;
port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port;
break;
}
switch (self->ith_state) {
case MACH_RCV_TOO_LARGE:
/* pick up size of the too-large message */
* (mach_msg_size_t *) kmsgp = self->ith_msize;
/* fall-through */
case MACH_RCV_PORT_DIED:
case MACH_RCV_PORT_CHANGED:
/* something bad happened to the port/set */
imq_unlock(mqueue);
return self->ith_state;
case MACH_RCV_IN_PROGRESS:
/*
* Awakened for other than IPC completion.
* Remove ourselves from the waiting queue,
* then check the wakeup cause.
*/
ipc_thread_rmqueue(&mqueue->imq_threads, self);
switch (self->ith_wait_result) {
case THREAD_INTERRUPTED:
/* receive was interrupted - give up */
imq_unlock(mqueue);
return MACH_RCV_INTERRUPTED;
case THREAD_TIMED_OUT:
/* timeout expired */
assert(option & MACH_RCV_TIMEOUT);
time_out = 0;
break;
case THREAD_RESTART:
default:
#if MACH_ASSERT
assert(!"ipc_mqueue_receive");
#else
panic("ipc_mqueue_receive");
#endif
}
break;
default:
#if MACH_ASSERT
assert(!"ipc_mqueue_receive: strange ith_state");
#else
panic("ipc_mqueue_receive: strange ith_state");
#endif
}
}
/* we have a kmsg; unlock the msg queue */
imq_unlock(mqueue);
assert(kmsg->ikm_header.msgh_size <= max_size);
}
{
ipc_marequest_t marequest;
marequest = kmsg->ikm_marequest;
if (marequest != IMAR_NULL) {
ipc_marequest_destroy(marequest);
kmsg->ikm_marequest = IMAR_NULL;
}
assert((kmsg->ikm_header.msgh_bits & MACH_MSGH_BITS_CIRCULAR) == 0);
assert(port == (ipc_port_t) kmsg->ikm_header.msgh_remote_port);
ip_lock(port);
if (ip_active(port)) {
ipc_thread_queue_t senders;
ipc_thread_t sender;
assert(port->ip_msgcount > 0);
port->ip_msgcount--;
senders = &port->ip_blocked;
sender = ipc_thread_queue_first(senders);
if ((sender != ITH_NULL) &&
(port->ip_msgcount < port->ip_qlimit)) {
ipc_thread_rmqueue(senders, sender);
sender->ith_state = MACH_MSG_SUCCESS;
thread_go(sender);
}
}
ip_unlock(port);
}
current_task()->messages_received++;
*kmsgp = kmsg;
*seqnop = seqno;
return MACH_MSG_SUCCESS;
}
/*
* thread_switch:
*
* Context switch. User may supply thread hint.
*
* Fixed priority threads that call this get what they asked for
* even if that violates priority order.
*/
kern_return_t thread_switch(
mach_port_t thread_name,
int option,
mach_msg_timeout_t option_time)
{
thread_t cur_thread = current_thread();
processor_t myprocessor;
ipc_port_t port;
/*
* Process option.
*/
switch (option) {
case SWITCH_OPTION_NONE:
/*
* Nothing to do.
*/
break;
case SWITCH_OPTION_DEPRESS:
/*
* Depress priority for given time.
*/
thread_depress_priority(cur_thread, option_time);
break;
case SWITCH_OPTION_WAIT:
thread_will_wait_with_timeout(cur_thread, option_time);
break;
default:
return(KERN_INVALID_ARGUMENT);
}
#ifndef MIGRATING_THREADS /* XXX thread_run defunct */
/*
* Check and act on thread hint if appropriate.
*/
if ((thread_name != 0) &&
(ipc_port_translate_send(cur_thread->task->itk_space,
thread_name, &port) == KERN_SUCCESS)) {
/* port is locked, but it might not be active */
/*
* Get corresponding thread.
*/
if (ip_active(port) && (ip_kotype(port) == IKOT_THREAD)) {
thread_t thread;
spl_t s;
thread = (thread_t) port->ip_kobject;
/*
* Check if the thread is in the right pset. Then
* pull it off its run queue. If it
* doesn't come, then it's not eligible.
*/
s = splsched();
thread_lock(thread);
if ((thread->processor_set == cur_thread->processor_set)
&& (rem_runq(thread) != RUN_QUEUE_NULL)) {
/*
* Hah, got it!!
*/
thread_unlock(thread);
(void) splx(s);
ip_unlock(port);
/* XXX thread might disappear on us now? */
#if MACH_FIXPRI
if (thread->policy == POLICY_FIXEDPRI) {
myprocessor = current_processor();
myprocessor->quantum = thread->sched_data;
myprocessor->first_quantum = TRUE;
}
#endif /* MACH_FIXPRI */
counter(c_thread_switch_handoff++);
thread_run(thread_switch_continue, thread);
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
return(KERN_SUCCESS);
}
thread_unlock(thread);
(void) splx(s);
}
ip_unlock(port);
}
#endif /* not MIGRATING_THREADS */
/*
* No handoff hint supplied, or hint was wrong. Call thread_block() in
* hopes of running something else. If nothing else is runnable,
* thread_block will detect this. WARNING: thread_switch with no
* option will not do anything useful if the thread calling it is the
* highest priority thread (can easily happen with a collection
* of timesharing threads).
*/
#if NCPUS > 1
myprocessor = current_processor();
if (myprocessor->processor_set->runq.count > 0 ||
myprocessor->runq.count > 0)
#endif /* NCPUS > 1 */
{
counter(c_thread_switch_block++);
thread_block(thread_switch_continue);
}
/*
* Restore depressed priority
*/
if (cur_thread->depress_priority >= 0)
(void) thread_depress_abort(cur_thread);
return(KERN_SUCCESS);
}
mach_msg_return_t
ipc_mqueue_send(
ipc_kmsg_t kmsg,
mach_msg_option_t option,
mach_msg_timeout_t time_out)
{
ipc_port_t port;
port = (ipc_port_t) kmsg->ikm_header.msgh_remote_port;
assert(IP_VALID(port));
ip_lock(port);
if (port->ip_receiver == ipc_space_kernel) {
ipc_kmsg_t reply;
/*
* We can check ip_receiver == ipc_space_kernel
* before checking that the port is active because
* ipc_port_dealloc_kernel clears ip_receiver
* before destroying a kernel port.
*/
assert(ip_active(port));
ip_unlock(port);
reply = ipc_kobject_server(kmsg);
if (reply != IKM_NULL)
ipc_mqueue_send_always(reply);
return MACH_MSG_SUCCESS;
}
for (;;) {
ipc_thread_t self;
/*
* Can't deliver to a dead port.
* However, we can pretend it got sent
* and was then immediately destroyed.
*/
if (!ip_active(port)) {
/*
* We can't let ipc_kmsg_destroy deallocate
* the port right, because we might end up
* in an infinite loop trying to deliver
* a send-once notification.
*/
ip_release(port);
ip_check_unlock(port);
kmsg->ikm_header.msgh_remote_port = MACH_PORT_NULL;
ipc_kmsg_destroy(kmsg);
return MACH_MSG_SUCCESS;
}
/*
* Don't block if:
* 1) We're under the queue limit.
* 2) Caller used the MACH_SEND_ALWAYS internal option.
* 3) Message is sent to a send-once right.
*/
if ((port->ip_msgcount < port->ip_qlimit) ||
(option & MACH_SEND_ALWAYS) ||
(MACH_MSGH_BITS_REMOTE(kmsg->ikm_header.msgh_bits) ==
MACH_MSG_TYPE_PORT_SEND_ONCE))
break;
/* must block waiting for queue to clear */
self = current_thread();
if (option & MACH_SEND_TIMEOUT) {
if (time_out == 0) {
ip_unlock(port);
return MACH_SEND_TIMED_OUT;
}
thread_will_wait_with_timeout(self, time_out);
} else
thread_will_wait(self);
ipc_thread_enqueue(&port->ip_blocked, self);
self->ith_state = MACH_SEND_IN_PROGRESS;
ip_unlock(port);
counter(c_ipc_mqueue_send_block++);
thread_block((void (*)(void)) 0);
ip_lock(port);
/* why did we wake up? */
if (self->ith_state == MACH_MSG_SUCCESS)
continue;
assert(self->ith_state == MACH_SEND_IN_PROGRESS);
/* take ourselves off blocked queue */
ipc_thread_rmqueue(&port->ip_blocked, self);
/*
* Thread wakeup-reason field tells us why
* the wait was interrupted.
*/
switch (self->ith_wait_result) {
case THREAD_INTERRUPTED:
/* send was interrupted - give up */
ip_unlock(port);
return MACH_SEND_INTERRUPTED;
case THREAD_TIMED_OUT:
/* timeout expired */
assert(option & MACH_SEND_TIMEOUT);
time_out = 0;
break;
case THREAD_RESTART:
default:
#if MACH_ASSERT
assert(!"ipc_mqueue_send");
#else
panic("ipc_mqueue_send");
#endif
}
}
if (kmsg->ikm_header.msgh_bits & MACH_MSGH_BITS_CIRCULAR) {
ip_unlock(port);
/* don't allow the creation of a circular loop */
ipc_kmsg_destroy(kmsg);
return MACH_MSG_SUCCESS;
}
{
ipc_mqueue_t mqueue;
ipc_pset_t pset;
ipc_thread_t receiver;
ipc_thread_queue_t receivers;
port->ip_msgcount++;
assert(port->ip_msgcount > 0);
pset = port->ip_pset;
if (pset == IPS_NULL)
mqueue = &port->ip_messages;
else
mqueue = &pset->ips_messages;
imq_lock(mqueue);
receivers = &mqueue->imq_threads;
/*
* Can unlock the port now that the msg queue is locked
* and we know the port is active. While the msg queue
* is locked, we have control of the kmsg, so the ref in
* it for the port is still good. If the msg queue is in
* a set (dead or alive), then we're OK because the port
* is still a member of the set and the set won't go away
* until the port is taken out, which tries to lock the
* set's msg queue to remove the port's msgs.
*/
ip_unlock(port);
/* check for a receiver for the message */
for (;;) {
receiver = ipc_thread_queue_first(receivers);
if (receiver == ITH_NULL) {
/* no receivers; queue kmsg */
ipc_kmsg_enqueue_macro(&mqueue->imq_messages, kmsg);
imq_unlock(mqueue);
break;
}
ipc_thread_rmqueue_first_macro(receivers, receiver);
assert(ipc_kmsg_queue_empty(&mqueue->imq_messages));
if (kmsg->ikm_header.msgh_size <= receiver->ith_msize) {
/* got a successful receiver */
receiver->ith_state = MACH_MSG_SUCCESS;
receiver->ith_kmsg = kmsg;
receiver->ith_seqno = port->ip_seqno++;
imq_unlock(mqueue);
thread_go(receiver);
break;
}
receiver->ith_state = MACH_RCV_TOO_LARGE;
receiver->ith_msize = kmsg->ikm_header.msgh_size;
thread_go(receiver);
}
}
current_task()->messages_sent++;
return MACH_MSG_SUCCESS;
}
