kern_return_t
semaphore_timedwait_signal_trap_internal(
mach_port_name_t wait_name,
mach_port_name_t signal_name,
unsigned int sec,
clock_res_t nsec,
void (*caller_cont)(kern_return_t))
{
semaphore_t wait_semaphore;
semaphore_t signal_semaphore;
mach_timespec_t wait_time;
kern_return_t kr;
wait_time.tv_sec = sec;
wait_time.tv_nsec = nsec;
if(BAD_MACH_TIMESPEC(&wait_time))
return KERN_INVALID_VALUE;
kr = port_name_to_semaphore(signal_name, &signal_semaphore);
if (kr == KERN_SUCCESS) {
kr = port_name_to_semaphore(wait_name, &wait_semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_wait_internal(wait_semaphore,
signal_semaphore,
&wait_time,
caller_cont);
semaphore_dereference(wait_semaphore);
}
semaphore_dereference(signal_semaphore);
}
return kr;
}
/*
* Routine: semaphore_destroy
*
* Destroys a semaphore and consume the caller's reference on the
* semaphore.
*/
kern_return_t
semaphore_destroy(
task_t task,
semaphore_t semaphore)
{
spl_t spl_level;
if (semaphore == SEMAPHORE_NULL)
return KERN_INVALID_ARGUMENT;
if (task == TASK_NULL) {
semaphore_dereference(semaphore);
return KERN_INVALID_ARGUMENT;
}
task_lock(task);
spl_level = splsched();
semaphore_lock(semaphore);
if (semaphore->owner != task) {
semaphore_unlock(semaphore);
splx(spl_level);
task_unlock(task);
return KERN_INVALID_ARGUMENT;
}
semaphore_destroy_internal(task, semaphore);
/* semaphore unlocked */
splx(spl_level);
task_unlock(task);
semaphore_dereference(semaphore);
return KERN_SUCCESS;
}
/*
* Routine: semaphore_wait_continue
*
* Common continuation routine after waiting on a semphore.
* It returns directly to user space.
*/
void
semaphore_wait_continue(void)
{
thread_t self = current_thread();
int wait_result = self->wait_result;
void (*caller_cont)(kern_return_t) = self->sth_continuation;
assert(self->sth_waitsemaphore != SEMAPHORE_NULL);
semaphore_dereference(self->sth_waitsemaphore);
if (self->sth_signalsemaphore != SEMAPHORE_NULL)
semaphore_dereference(self->sth_signalsemaphore);
assert(caller_cont != (void (*)(kern_return_t))0);
(*caller_cont)(semaphore_convert_wait_result(wait_result));
}
/*
* Routine: semaphore_signal_thread_trap
*
* Trap interface to the semaphore_signal_thread function.
*/
kern_return_t
semaphore_signal_thread_trap(
struct semaphore_signal_thread_trap_args *args)
{
mach_port_name_t sema_name = args->signal_name;
mach_port_name_t thread_name = args->thread_name;
semaphore_t semaphore;
thread_t thread;
kern_return_t kr;
/*
* MACH_PORT_NULL is not an error. It means that we want to
* select any one thread that is already waiting, but not to
* pre-post the semaphore.
*/
if (thread_name != MACH_PORT_NULL) {
thread = port_name_to_thread(thread_name);
if (thread == THREAD_NULL)
return KERN_INVALID_ARGUMENT;
} else
thread = THREAD_NULL;
kr = port_name_to_semaphore(sema_name, &semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_signal_internal(semaphore,
thread,
SEMAPHORE_OPTION_NONE);
semaphore_dereference(semaphore);
}
if (thread != THREAD_NULL) {
thread_deallocate(thread);
}
return kr;
}
/*
* Routine: semaphore_destroy
*
* Destroys a semaphore. This call will only succeed if the
* specified task is the SAME task name specified at the semaphore's
* creation.
*
* All threads currently blocked on the semaphore are awoken. These
* threads will return with the KERN_TERMINATED error.
*/
kern_return_t
semaphore_destroy(
task_t task,
semaphore_t semaphore)
{
int old_count;
spl_t spl_level;
if (task == TASK_NULL || semaphore == SEMAPHORE_NULL)
return KERN_INVALID_ARGUMENT;
/*
* Disown semaphore
*/
task_lock(task);
if (semaphore->owner != task) {
task_unlock(task);
return KERN_INVALID_ARGUMENT;
}
remqueue(&task->semaphore_list, (queue_entry_t) semaphore);
semaphore->owner = TASK_NULL;
task->semaphores_owned--;
task_unlock(task);
spl_level = splsched();
semaphore_lock(semaphore);
/*
* Deactivate semaphore
*/
assert(semaphore->active);
semaphore->active = FALSE;
/*
* Wakeup blocked threads
*/
old_count = semaphore->count;
semaphore->count = 0;
if (old_count < 0) {
wait_queue_wakeup64_all_locked(&semaphore->wait_queue,
SEMAPHORE_EVENT,
THREAD_RESTART,
TRUE); /* unlock? */
} else {
semaphore_unlock(semaphore);
}
splx(spl_level);
/*
* Deallocate
*
* Drop the semaphore reference, which in turn deallocates the
* semaphore structure if the reference count goes to zero.
*/
ipc_port_dealloc_kernel(semaphore->port);
semaphore_dereference(semaphore);
return KERN_SUCCESS;
}
kern_return_t
semaphore_timedwait_trap_internal(
mach_port_name_t name,
unsigned int sec,
clock_res_t nsec,
void (*caller_cont)(kern_return_t))
{
semaphore_t semaphore;
mach_timespec_t wait_time;
kern_return_t kr;
wait_time.tv_sec = sec;
wait_time.tv_nsec = nsec;
if(BAD_MACH_TIMESPEC(&wait_time))
return KERN_INVALID_VALUE;
kr = port_name_to_semaphore(name, &semaphore);
if (kr == KERN_SUCCESS) {
int option = SEMAPHORE_OPTION_NONE;
uint64_t deadline = 0;
if (sec == 0 && nsec == 0)
option = SEMAPHORE_TIMEOUT_NOBLOCK;
else
deadline = semaphore_deadline(sec, nsec);
kr = semaphore_wait_internal(semaphore,
SEMAPHORE_NULL,
deadline, option,
caller_cont);
semaphore_dereference(semaphore);
}
return kr;
}
/*
* Routine: semaphore_create
*
* Creates a semaphore.
* The port representing the semaphore is returned as a parameter.
*/
kern_return_t
semaphore_create(
task_t task,
semaphore_t *new_semaphore,
int policy,
int value)
{
semaphore_t s = SEMAPHORE_NULL;
if (task == TASK_NULL || value < 0 || policy > SYNC_POLICY_MAX) {
*new_semaphore = SEMAPHORE_NULL;
return KERN_INVALID_ARGUMENT;
}
s = (semaphore_t) zalloc (semaphore_zone);
if (s == SEMAPHORE_NULL) {
*new_semaphore = SEMAPHORE_NULL;
return KERN_RESOURCE_SHORTAGE;
}
wait_queue_init(&s->wait_queue, policy); /* also inits lock */
s->count = value;
s->ref_count = 1;
/*
* Create and initialize the semaphore port
*/
s->port = ipc_port_alloc_kernel();
if (s->port == IP_NULL) {
/* This will deallocate the semaphore */
semaphore_dereference(s);
*new_semaphore = SEMAPHORE_NULL;
return KERN_RESOURCE_SHORTAGE;
}
ipc_kobject_set (s->port, (ipc_kobject_t) s, IKOT_SEMAPHORE);
/*
* Associate the new semaphore with the task by adding
* the new semaphore to the task's semaphore list.
*
* Associate the task with the new semaphore by having the
* semaphores task pointer point to the owning task's structure.
*/
task_lock(task);
enqueue_head(&task->semaphore_list, (queue_entry_t) s);
task->semaphores_owned++;
s->owner = task;
s->active = TRUE;
task_unlock(task);
*new_semaphore = s;
return KERN_SUCCESS;
}
/*
* Routine: semaphore_notify
* Purpose:
* Called whenever the Mach port system detects no-senders
* on the semaphore port.
*
* When a send-right is first created, a no-senders
* notification is armed (and a semaphore reference is donated).
*
* A no-senders notification will be posted when no one else holds a
* send-right (reference) to the semaphore's port. This notification function
* will consume the semaphore reference donated to the extant collection of
* send-rights.
*/
void
semaphore_notify(mach_msg_header_t *msg)
{
mach_no_senders_notification_t *notification = (void *)msg;
ipc_port_t port = notification->not_header.msgh_remote_port;
semaphore_t semaphore;
assert(ip_active(port));
assert(IKOT_SEMAPHORE == ip_kotype(port));
semaphore = (semaphore_t)port->ip_kobject;
semaphore_dereference(semaphore);
}
kern_return_t
semaphore_wait_signal_trap_internal(
mach_port_name_t wait_name,
mach_port_name_t signal_name,
void (*caller_cont)(kern_return_t))
{
semaphore_t wait_semaphore;
semaphore_t signal_semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(signal_name, &signal_semaphore);
if (kr == KERN_SUCCESS) {
kr = port_name_to_semaphore(wait_name, &wait_semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_wait_internal(wait_semaphore,
signal_semaphore,
(mach_timespec_t *)0,
caller_cont);
semaphore_dereference(wait_semaphore);
}
semaphore_dereference(signal_semaphore);
}
return kr;
}
kern_return_t
semaphore_wait_signal_trap_internal(
mach_port_name_t wait_name,
mach_port_name_t signal_name,
void (*caller_cont)(kern_return_t))
{
semaphore_t wait_semaphore;
semaphore_t signal_semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(signal_name, &signal_semaphore);
if (kr == KERN_SUCCESS) {
kr = port_name_to_semaphore(wait_name, &wait_semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_wait_internal(wait_semaphore,
signal_semaphore,
0ULL, SEMAPHORE_OPTION_NONE,
caller_cont);
semaphore_dereference(wait_semaphore);
}
semaphore_dereference(signal_semaphore);
}
return kr;
}
kern_return_t
semaphore_signal_internal_trap(mach_port_name_t sema_name)
{
semaphore_t semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(sema_name, &semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_signal_internal(semaphore,
THREAD_NULL,
SEMAPHORE_SIGNAL_PREPOST);
semaphore_dereference(semaphore);
if (kr == KERN_NOT_WAITING)
kr = KERN_SUCCESS;
}
return kr;
}
kern_return_t
semaphore_wait_trap_internal(
mach_port_name_t name,
void (*caller_cont)(kern_return_t))
{
semaphore_t semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(name, &semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_wait_internal(semaphore,
SEMAPHORE_NULL,
(mach_timespec_t *)0,
caller_cont);
semaphore_dereference(semaphore);
}
return kr;
}
/*
* Routine: convert_semaphore_to_port
* Purpose:
* Convert a semaphore reference to a send right to a
* semaphore port.
*
* Consumes the semaphore reference. If the semaphore
* port currently has no send rights (or doesn't exist
* yet), the reference is donated to the port to represent
* all extant send rights collectively.
*/
ipc_port_t
convert_semaphore_to_port (semaphore_t semaphore)
{
ipc_port_t port, send;
if (semaphore == SEMAPHORE_NULL)
return (IP_NULL);
/* caller is donating a reference */
port = semaphore->port;
if (!IP_VALID(port)) {
port = ipc_port_alloc_kernel();
assert(IP_VALID(port));
ipc_kobject_set_atomically(port, (ipc_kobject_t) semaphore, IKOT_SEMAPHORE);
/* If we lose the race, deallocate and pick up the other guy's port */
if (!OSCompareAndSwapPtr(IP_NULL, port, &semaphore->port)) {
ipc_port_dealloc_kernel(port);
port = semaphore->port;
assert(ip_kotype(port) == IKOT_SEMAPHORE);
assert(port->ip_kobject == (ipc_kobject_t)semaphore);
}
}
ip_lock(port);
assert(ip_active(port));
send = ipc_port_make_send_locked(port);
if (1 == port->ip_srights) {
ipc_port_t old_notify;
/* transfer our ref to the port, and arm the no-senders notification */
assert(IP_NULL == port->ip_nsrequest);
ipc_port_nsrequest(port, port->ip_mscount, ipc_port_make_sonce_locked(port), &old_notify);
/* port unlocked */
assert(IP_NULL == old_notify);
} else {
/* piggyback on the existing port reference, so consume ours */
ip_unlock(port);
semaphore_dereference(semaphore);
}
return (send);
}
/*
* Routine: semaphore_signal_all_trap
*
* Trap interface to the semaphore_signal_all function.
*/
kern_return_t
semaphore_signal_all_trap(
struct semaphore_signal_all_trap_args *args)
{
mach_port_name_t sema_name = args->signal_name;
semaphore_t semaphore;
kern_return_t kr;
kr = port_name_to_semaphore(sema_name, &semaphore);
if (kr == KERN_SUCCESS) {
kr = semaphore_signal_internal(semaphore,
THREAD_NULL,
SEMAPHORE_SIGNAL_ALL);
semaphore_dereference(semaphore);
if (kr == KERN_NOT_WAITING)
kr = KERN_SUCCESS;
}
return kr;
}
