+/*
+ * Routine: mig_object_init
+ * Purpose:
+ * Initialize the base class portion of a MIG object. We
+ * will lazy init the port, so just clear it for now.
+ */
+kern_return_t
+mig_object_init(
+ mig_object_t mig_object,
+ const IMIGObject *interface)
+{
+ if (mig_object == MIG_OBJECT_NULL)
+ return KERN_INVALID_ARGUMENT;
+ mig_object->pVtbl = (const IMIGObjectVtbl *)interface;
+ mig_object->port = MACH_PORT_NULL;
+ return KERN_SUCCESS;
+}
+
+/*
+ * Routine: mig_object_destroy
+ * Purpose:
+ * The object is being freed. This call lets us clean
+ * up any state we have have built up over the object's
+ * lifetime.
+ * Conditions:
+ * Since notifications and the port hold references on
+ * on the object, neither can exist when this is called.
+ * This is a good place to assert() that condition.
+ */
+void
+mig_object_destroy(
+ __assert_only mig_object_t mig_object)
+{
+ assert(mig_object->port == MACH_PORT_NULL);
+ return;
+}
+
+/*
+ * Routine: mig_object_reference
+ * Purpose:
+ * Pure virtual helper to invoke the MIG object's AddRef
+ * method.
+ * Conditions:
+ * MIG object port may be locked.
+ */
+void
+mig_object_reference(
+ mig_object_t mig_object)
+{
+ assert(mig_object != MIG_OBJECT_NULL);
+ mig_object->pVtbl->AddRef((IMIGObject *)mig_object);
+}
+
+/*
+ * Routine: mig_object_deallocate
+ * Purpose:
+ * Pure virtual helper to invoke the MIG object's Release
+ * method.
+ * Conditions:
+ * Nothing locked.
+ */
+void
+mig_object_deallocate(
+ mig_object_t mig_object)
+{
+ assert(mig_object != MIG_OBJECT_NULL);
+ mig_object->pVtbl->Release((IMIGObject *)mig_object);
+}
+
+/*
+ * Routine: convert_mig_object_to_port [interface]
+ * Purpose:
+ * Base implementation of MIG outtrans routine to convert from
+ * a mig object reference to a new send right on the object's
+ * port. The object reference is consumed.
+ * Returns:
+ * IP_NULL - Null MIG object supplied
+ * Otherwise, a newly made send right for the port
+ * Conditions:
+ * Nothing locked.
+ */
+ipc_port_t
+convert_mig_object_to_port(
+ mig_object_t mig_object)
+{
+ ipc_port_t port;
+ boolean_t deallocate = TRUE;
+
+ if (mig_object == MIG_OBJECT_NULL)
+ return IP_NULL;
+
+ port = mig_object->port;
+ while ((port == IP_NULL) ||
+ ((port = ipc_port_make_send(port)) == IP_NULL)) {
+ ipc_port_t previous;
+
+ /*
+ * Either the port was never set up, or it was just
+ * deallocated out from under us by the no-senders
+ * processing. In either case, we must:
+ * Attempt to make one
+ * Arrange for no senders
+ * Try to atomically register it with the object
+ * Destroy it if we are raced.
+ */
+ port = ipc_port_alloc_kernel();
+ ip_lock(port);
+ ipc_kobject_set_atomically(port,
+ (ipc_kobject_t) mig_object,
+ IKOT_MIG);
+
+ /* make a sonce right for the notification */
+ port->ip_sorights++;
+ ip_reference(port);
+
+ ipc_port_nsrequest(port, 1, port, &previous);
+ /* port unlocked */
+
+ assert(previous == IP_NULL);
+
+ if (hw_compare_and_store((uint32_t)IP_NULL, (uint32_t)port,
+ (uint32_t *)&mig_object->port)) {
+ deallocate = FALSE;
+ } else {
+ ipc_port_dealloc_kernel(port);
+ port = mig_object->port;
+ }
+ }
+
+ if (deallocate)
+ mig_object->pVtbl->Release((IMIGObject *)mig_object);
+
+ return (port);
+}
+
+
+/*
+ * Routine: convert_port_to_mig_object [interface]
+ * Purpose:
+ * Base implementation of MIG intrans routine to convert from
+ * an incoming port reference to a new reference on the
+ * underlying object. A new reference must be created, because
+ * the port's reference could go away asynchronously.
+ * Returns:
+ * NULL - Not an active MIG object port or iid not supported
+ * Otherwise, a reference to the underlying MIG interface
+ * Conditions:
+ * Nothing locked.
+ */
+mig_object_t
+convert_port_to_mig_object(
+ ipc_port_t port,
+ const MIGIID *iid)
+{
+ mig_object_t mig_object;
+ void *ppv;
+
+ if (!IP_VALID(port))
+ return NULL;
+
+ ip_lock(port);
+ if (!ip_active(port) || (ip_kotype(port) != IKOT_MIG)) {
+ ip_unlock(port);
+ return NULL;
+ }
+
+ /*
+ * Our port points to some MIG object interface. Now
+ * query it to get a reference to the desired interface.
+ */
+ ppv = NULL;
+ mig_object = (mig_object_t)port->ip_kobject;
+ mig_object->pVtbl->QueryInterface((IMIGObject *)mig_object, iid, &ppv);
+ ip_unlock(port);
+ return (mig_object_t)ppv;
+}
+
+/*
+ * Routine: mig_object_no_senders [interface]
+ * Purpose:
+ * Base implementation of a no-senders notification handler
+ * for MIG objects. If there truly are no more senders, must
+ * destroy the port and drop its reference on the object.
+ * Returns:
+ * TRUE - port deallocate and reference dropped
+ * FALSE - more senders arrived, re-registered for notification
+ * Conditions:
+ * Nothing locked.
+ */
+
+boolean_t
+mig_object_no_senders(
+ ipc_port_t port,
+ mach_port_mscount_t mscount)
+{
+ mig_object_t mig_object;
+
+ ip_lock(port);
+ if (port->ip_mscount > mscount) {
+ ipc_port_t previous;
+
+ /*
+ * Somebody created new send rights while the
+ * notification was in-flight. Just create a
+ * new send-once right and re-register with
+ * the new (higher) mscount threshold.
+ */
+ /* make a sonce right for the notification */
+ port->ip_sorights++;
+ ip_reference(port);
+ ipc_port_nsrequest(port, mscount, port, &previous);
+ /* port unlocked */
+
+ assert(previous == IP_NULL);
+ return (FALSE);
+ }
+
+ /*
+ * Clear the port pointer while we have it locked.
+ */
+ mig_object = (mig_object_t)port->ip_kobject;
+ mig_object->port = IP_NULL;
+
+ /*
+ * Bring the sequence number and mscount in
+ * line with ipc_port_destroy assertion.
+ */
+ port->ip_mscount = 0;
+ port->ip_messages.imq_seqno = 0;
+ ipc_port_destroy(port); /* releases lock */
+
+ /*
+ * Release the port's reference on the object.
+ */
+ mig_object->pVtbl->Release((IMIGObject *)mig_object);
+ return (TRUE);
+}
+
+/*
+ * Kernel implementation of the notification chain for MIG object
+ * is kept separate from the actual objects, since there are expected
+ * to be much fewer of them than actual objects.
+ *
+ * The implementation of this part of MIG objects is coming
+ * "Real Soon Now"(TM).
+ */
projects / apple / xnu.git / blobdiff