* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- *
+ *
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
- *
+ *
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
- *
+ *
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
- *
+ *
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
- *
+ *
*/
#include <kern/sync_sema.h>
#include <ipc/port.h>
#include <ipc/ipc_space.h>
#include <ipc/ipc_port.h>
+#include <mach/mach_types.h>
#include <mach/semaphore.h>
#include <mach/lock_set_server.h>
#include <mach/mach_port_server.h>
#include <mach/port.h>
+/*
+ * Routine: port_name_to_semaphore
+ * Purpose:
+ * Convert from a port name in the current space to a semaphore.
+ * Produces a semaphore ref, which may be null.
+ * Conditions:
+ * Nothing locked.
+ */
kern_return_t
port_name_to_semaphore(
- mach_port_name_t name,
- semaphore_t *semaphorep)
+ mach_port_name_t name,
+ semaphore_t *semaphorep)
{
- semaphore_t semaphore;
ipc_port_t kern_port;
kern_return_t kr;
*semaphorep = SEMAPHORE_NULL;
return KERN_INVALID_NAME;
}
-
- kr = ipc_object_translate(current_space(), name, MACH_PORT_RIGHT_SEND,
- (ipc_object_t *) &kern_port);
+
+ kr = ipc_port_translate_send(current_space(), name, &kern_port);
if (kr != KERN_SUCCESS) {
*semaphorep = SEMAPHORE_NULL;
return kr;
/* have the port locked */
assert(IP_VALID(kern_port));
- if (!ip_active(kern_port) || (ip_kotype(kern_port) != IKOT_SEMAPHORE)) {
- ip_unlock(kern_port);
- *semaphorep = SEMAPHORE_NULL;
- return KERN_INVALID_ARGUMENT;
+ *semaphorep = convert_port_to_semaphore(kern_port);
+ if (*semaphorep == SEMAPHORE_NULL) {
+ /* the port is valid, but doesn't denote a semaphore */
+ kr = KERN_INVALID_CAPABILITY;
+ } else {
+ kr = KERN_SUCCESS;
}
-
- semaphore = (semaphore_t) kern_port->ip_kobject;
- assert(semaphore != SEMAPHORE_NULL);
- semaphore_reference(semaphore);
ip_unlock(kern_port);
- *semaphorep = semaphore;
- return KERN_SUCCESS;
+ return kr;
}
-
+
+/*
+ * Routine: convert_port_to_semaphore
+ * Purpose:
+ * Convert from a port to a semaphore.
+ * Doesn't consume the port [send-right] ref;
+ * produces a semaphore ref, which may be null.
+ * Conditions:
+ * Caller has a send-right reference to port.
+ * Port may or may not be locked.
+ */
semaphore_t
-convert_port_to_semaphore (ipc_port_t port)
+convert_port_to_semaphore(ipc_port_t port)
{
- semaphore_t semaphore = SEMAPHORE_NULL;
-
- if (IP_VALID (port)) {
- ip_lock(port);
- if (ip_active(port) && (ip_kotype(port) == IKOT_SEMAPHORE)) {
+ if (IP_VALID(port)) {
+ semaphore_t semaphore;
+
+ /*
+ * No need to lock because we have a reference on the
+ * port, and if it is a true semaphore port, that reference
+ * keeps the semaphore bound to the port (and active).
+ */
+ if (ip_kotype(port) == IKOT_SEMAPHORE) {
+ require_ip_active(port);
semaphore = (semaphore_t) port->ip_kobject;
semaphore_reference(semaphore);
+ return semaphore;
}
- ip_unlock(port);
}
-
- return (semaphore);
+ return SEMAPHORE_NULL;
}
+/*
+ * 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)
+convert_semaphore_to_port(semaphore_t semaphore)
+{
+ if (semaphore == SEMAPHORE_NULL) {
+ return IP_NULL;
+ }
+
+ /*
+ * make a send right and donate our reference for
+ * semaphore_notify if this is the first send right
+ */
+ if (!ipc_kobject_make_send_lazy_alloc_port(&semaphore->port,
+ (ipc_kobject_t) semaphore, IKOT_SEMAPHORE)) {
+ semaphore_dereference(semaphore);
+ }
+ return semaphore->port;
+}
+
+/*
+ * 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)
{
- ipc_port_t port;
+ mach_no_senders_notification_t *notification = (void *)msg;
+ ipc_port_t port = notification->not_header.msgh_remote_port;
- if (semaphore == SEMAPHORE_NULL)
- return (IP_NULL);
+ require_ip_active(port);
+ assert(IKOT_SEMAPHORE == ip_kotype(port));
- /* caller is donating a reference */
- port = ipc_port_make_send(semaphore->port);
- semaphore_dereference(semaphore);
- return (port);
+ semaphore_dereference((semaphore_t)port->ip_kobject);
}
lock_set_t
-convert_port_to_lock_set (__unused ipc_port_t port)
+convert_port_to_lock_set(__unused ipc_port_t port)
{
- return (LOCK_SET_NULL);
+ return LOCK_SET_NULL;
}
ipc_port_t
-convert_lock_set_to_port (__unused lock_set_t lock_set)
+convert_lock_set_to_port(__unused lock_set_t lock_set)
{
- return (IP_NULL);
+ return IP_NULL;
}
-
projects / apple / xnu.git / blobdiff