Initial source

1 files changed, 1398 insertions, 0 deletions

diff --git a/kern/ipc_tt.c b/kern/ipc_tt.c
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+/* 
+ * Mach Operating System
+ * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
+ * All Rights Reserved.
+ * 
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ * 
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ * 
+ * any improvements or extensions that they make and grant Carnegie Mellon
+ * the rights to redistribute these changes.
+ */
+/*
+ * File:	ipc_tt.c
+ * Purpose:
+ *	Task and thread related IPC functions.
+ */
+
+#include <mach_ipc_compat.h>
+
+#include <mach/boolean.h>
+#include <mach/kern_return.h>
+#include <mach/mach_param.h>
+#include <mach/task_special_ports.h>
+#include <mach/thread_special_ports.h>
+#include <vm/vm_kern.h>
+#include <kern/task.h>
+#include <kern/thread.h>
+#include <kern/ipc_kobject.h>
+#include <kern/ipc_tt.h>
+#include <ipc/ipc_space.h>
+#include <ipc/ipc_table.h>
+#include <ipc/ipc_port.h>
+#include <ipc/ipc_right.h>
+#include <ipc/ipc_entry.h>
+#include <ipc/ipc_object.h>
+
+
+
+/*
+ *	Routine:	ipc_task_init
+ *	Purpose:
+ *		Initialize a task's IPC state.
+ *
+ *		If non-null, some state will be inherited from the parent.
+ *		The parent must be appropriately initialized.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+ipc_task_init(
+	task_t		task,
+	task_t		parent)
+{
+	ipc_space_t space;
+	ipc_port_t kport;
+	kern_return_t kr;
+	int i;
+
+
+	kr = ipc_space_create(&ipc_table_entries[0], &space);
+	if (kr != KERN_SUCCESS)
+		panic("ipc_task_init");
+
+
+	kport = ipc_port_alloc_kernel();
+	if (kport == IP_NULL)
+		panic("ipc_task_init");
+
+	itk_lock_init(task);
+	task->itk_self = kport;
+	task->itk_sself = ipc_port_make_send(kport);
+	task->itk_space = space;
+
+	if (parent == TASK_NULL) {
+		task->itk_exception = IP_NULL;
+		task->itk_bootstrap = IP_NULL;
+		for (i = 0; i < TASK_PORT_REGISTER_MAX; i++)
+			task->itk_registered[i] = IP_NULL;
+	} else {
+		itk_lock(parent);
+		assert(parent->itk_self != IP_NULL);
+
+		/* inherit registered ports */
+
+		for (i = 0; i < TASK_PORT_REGISTER_MAX; i++)
+			task->itk_registered[i] =
+				ipc_port_copy_send(parent->itk_registered[i]);
+
+		/* inherit exception and bootstrap ports */
+
+		task->itk_exception =
+			ipc_port_copy_send(parent->itk_exception);
+		task->itk_bootstrap =
+			ipc_port_copy_send(parent->itk_bootstrap);
+
+		itk_unlock(parent);
+	}
+}
+
+/*
+ *	Routine:	ipc_task_enable
+ *	Purpose:
+ *		Enable a task for IPC access.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+ipc_task_enable(
+	task_t		task)
+{
+	ipc_port_t kport;
+
+	itk_lock(task);
+	kport = task->itk_self;
+	if (kport != IP_NULL)
+		ipc_kobject_set(kport, (ipc_kobject_t) task, IKOT_TASK);
+	itk_unlock(task);
+}
+
+/*
+ *	Routine:	ipc_task_disable
+ *	Purpose:
+ *		Disable IPC access to a task.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+ipc_task_disable(
+	task_t		task)
+{
+	ipc_port_t kport;
+
+	itk_lock(task);
+	kport = task->itk_self;
+	if (kport != IP_NULL)
+		ipc_kobject_set(kport, IKO_NULL, IKOT_NONE);
+	itk_unlock(task);
+}
+
+/*
+ *	Routine:	ipc_task_terminate
+ *	Purpose:
+ *		Clean up and destroy a task's IPC state.
+ *	Conditions:
+ *		Nothing locked.  The task must be suspended.
+ *		(Or the current thread must be in the task.)
+ */
+
+void
+ipc_task_terminate(
+	task_t		task)
+{
+	ipc_port_t kport;
+	int i;
+
+	itk_lock(task);
+	kport = task->itk_self;
+
+	if (kport == IP_NULL) {
+		/* the task is already terminated (can this happen?) */
+		itk_unlock(task);
+		return;
+	}
+
+	task->itk_self = IP_NULL;
+	itk_unlock(task);
+
+	/* release the naked send rights */
+
+	if (IP_VALID(task->itk_sself))
+		ipc_port_release_send(task->itk_sself);
+	if (IP_VALID(task->itk_exception))
+		ipc_port_release_send(task->itk_exception);
+	if (IP_VALID(task->itk_bootstrap))
+		ipc_port_release_send(task->itk_bootstrap);
+
+	for (i = 0; i < TASK_PORT_REGISTER_MAX; i++)
+		if (IP_VALID(task->itk_registered[i]))
+			ipc_port_release_send(task->itk_registered[i]);
+
+	/* destroy the space, leaving just a reference for it */
+
+	ipc_space_destroy(task->itk_space);
+
+	/* destroy the kernel port */
+
+	ipc_port_dealloc_kernel(kport);
+}
+
+/*
+ *	Routine:	ipc_thread_init
+ *	Purpose:
+ *		Initialize a thread's IPC state.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+ipc_thread_init(thread)
+	thread_t thread;
+{
+	ipc_port_t kport;
+
+	kport = ipc_port_alloc_kernel();
+	if (kport == IP_NULL)
+		panic("ipc_thread_init");
+
+	ipc_thread_links_init(thread);
+	ipc_kmsg_queue_init(&thread->ith_messages);
+
+	ith_lock_init(thread);
+	thread->ith_self = kport;
+	thread->ith_sself = ipc_port_make_send(kport);
+	thread->ith_exception = IP_NULL;
+
+	thread->ith_mig_reply = MACH_PORT_NULL;
+	thread->ith_rpc_reply = IP_NULL;
+
+#if	MACH_IPC_COMPAT
+    {
+	ipc_space_t space = thread->task->itk_space;
+	ipc_port_t port;
+	mach_port_t name;
+	kern_return_t kr;
+
+	kr = ipc_port_alloc_compat(space, &name, &port);
+	if (kr != KERN_SUCCESS)
+		panic("ipc_thread_init");
+	/* port is locked and active */
+
+	/*
+	 *	Now we have a reply port.  We need to make a naked
+	 *	send right to stash in ith_reply.  We can't use
+	 *	ipc_port_make_send, because we can't unlock the port
+	 *	before making the right.  Also we don't want to
+	 *	increment ip_mscount.  The net effect of all this
+	 *	is the same as doing
+	 *		ipc_port_alloc_kernel		get the port
+	 *		ipc_port_make_send		make the send right
+	 *		ipc_object_copyin_from_kernel	grab receive right
+	 *		ipc_object_copyout_compat	and give to user
+	 */
+
+	port->ip_srights++;
+	ip_reference(port);
+	ip_unlock(port);
+
+	thread->ith_reply = port;
+    }
+#endif	MACH_IPC_COMPAT
+}
+
+/*
+ *	Routine:	ipc_thread_enable
+ *	Purpose:
+ *		Enable a thread for IPC access.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+ipc_thread_enable(thread)
+	thread_t thread;
+{
+	ipc_port_t kport;
+
+	ith_lock(thread);
+	kport = thread->ith_self;
+	if (kport != IP_NULL)
+		ipc_kobject_set(kport, (ipc_kobject_t) thread, IKOT_THREAD);
+	ith_unlock(thread);
+}
+
+/*
+ *	Routine:	ipc_thread_disable
+ *	Purpose:
+ *		Disable IPC access to a thread.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+ipc_thread_disable(thread)
+	thread_t thread;
+{
+	ipc_port_t kport;
+
+	ith_lock(thread);
+	kport = thread->ith_self;
+	if (kport != IP_NULL)
+		ipc_kobject_set(kport, IKO_NULL, IKOT_NONE);
+	ith_unlock(thread);
+}
+
+/*
+ *	Routine:	ipc_thread_terminate
+ *	Purpose:
+ *		Clean up and destroy a thread's IPC state.
+ *	Conditions:
+ *		Nothing locked.  The thread must be suspended.
+ *		(Or be the current thread.)
+ */
+
+void
+ipc_thread_terminate(thread)
+	thread_t thread;
+{
+	ipc_port_t kport;
+
+	ith_lock(thread);
+	kport = thread->ith_self;
+
+	if (kport == IP_NULL) {
+		/* the thread is already terminated (can this happen?) */
+		ith_unlock(thread);
+		return;
+	}
+
+	thread->ith_self = IP_NULL;
+	ith_unlock(thread);
+
+	assert(ipc_kmsg_queue_empty(&thread->ith_messages));
+
+	/* release the naked send rights */
+
+	if (IP_VALID(thread->ith_sself))
+		ipc_port_release_send(thread->ith_sself);
+	if (IP_VALID(thread->ith_exception))
+		ipc_port_release_send(thread->ith_exception);
+
+#if	MACH_IPC_COMPAT
+	if (IP_VALID(thread->ith_reply)) {
+		ipc_space_t space = thread->task->itk_space;
+		ipc_port_t port = thread->ith_reply;
+		ipc_entry_t entry;
+		mach_port_t name;
+
+		/* destroy any rights the task may have for the port */
+
+		is_write_lock(space);
+		if (space->is_active &&
+		    ipc_right_reverse(space, (ipc_object_t) port,
+				      &name, &entry)) {
+			/* reply port is locked and active */
+			ip_unlock(port);
+
+			(void) ipc_right_destroy(space, name, entry);
+			/* space is unlocked */
+		} else
+			is_write_unlock(space);
+
+		ipc_port_release_send(port);
+	}
+
+	/*
+	 *	Note we do *not* destroy any rights the space may have
+	 *	for the thread's kernel port.  The old IPC code did this,
+	 *	to avoid generating a notification when the port is
+	 *	destroyed.  However, this isn't a good idea when
+	 *	the kernel port is interposed, because then it doesn't
+	 *	happen, exposing the interposition to the task.
+	 *	Because we don't need the efficiency hack, I flushed
+	 *	this behaviour, introducing a small incompatibility
+	 *	with the old IPC code.
+	 */
+#endif	MACH_IPC_COMPAT
+
+	/* destroy the kernel port */
+
+	ipc_port_dealloc_kernel(kport);
+}
+
+#if	0
+/*
+ *	Routine:	retrieve_task_self
+ *	Purpose:
+ *		Return a send right (possibly null/dead)
+ *		for the task's user-visible self port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_task_self(task)
+	task_t task;
+{
+	ipc_port_t port;
+
+	assert(task != TASK_NULL);
+
+	itk_lock(task);
+	if (task->itk_self != IP_NULL)
+		port = ipc_port_copy_send(task->itk_sself);
+	else
+		port = IP_NULL;
+	itk_unlock(task);
+
+	return port;
+}
+
+/*
+ *	Routine:	retrieve_thread_self
+ *	Purpose:
+ *		Return a send right (possibly null/dead)
+ *		for the thread's user-visible self port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_thread_self(thread)
+	thread_t thread;
+{
+	ipc_port_t port;
+
+	assert(thread != ITH_NULL);
+
+	ith_lock(thread);
+	if (thread->ith_self != IP_NULL)
+		port = ipc_port_copy_send(thread->ith_sself);
+	else
+		port = IP_NULL;
+	ith_unlock(thread);
+
+	return port;
+}
+#endif	0
+
+/*
+ *	Routine:	retrieve_task_self_fast
+ *	Purpose:
+ *		Optimized version of retrieve_task_self,
+ *		that only works for the current task.
+ *
+ *		Return a send right (possibly null/dead)
+ *		for the task's user-visible self port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_task_self_fast(
+	register task_t		task)
+{
+	register ipc_port_t port;
+
+	assert(task == current_task());
+
+	itk_lock(task);
+	assert(task->itk_self != IP_NULL);
+
+	if ((port = task->itk_sself) == task->itk_self) {
+		/* no interposing */
+
+		ip_lock(port);
+		assert(ip_active(port));
+		ip_reference(port);
+		port->ip_srights++;
+		ip_unlock(port);
+	} else
+		port = ipc_port_copy_send(port);
+	itk_unlock(task);
+
+	return port;
+}
+
+/*
+ *	Routine:	retrieve_thread_self_fast
+ *	Purpose:
+ *		Optimized version of retrieve_thread_self,
+ *		that only works for the current thread.
+ *
+ *		Return a send right (possibly null/dead)
+ *		for the thread's user-visible self port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_thread_self_fast(thread)
+	register thread_t thread;
+{
+	register ipc_port_t port;
+
+	assert(thread == current_thread());
+
+	ith_lock(thread);
+	assert(thread->ith_self != IP_NULL);
+
+	if ((port = thread->ith_sself) == thread->ith_self) {
+		/* no interposing */
+
+		ip_lock(port);
+		assert(ip_active(port));
+		ip_reference(port);
+		port->ip_srights++;
+		ip_unlock(port);
+	} else
+		port = ipc_port_copy_send(port);
+	ith_unlock(thread);
+
+	return port;
+}
+
+#if	0
+/*
+ *	Routine:	retrieve_task_exception
+ *	Purpose:
+ *		Return a send right (possibly null/dead)
+ *		for the task's exception port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_task_exception(task)
+	task_t task;
+{
+	ipc_port_t port;
+
+	assert(task != TASK_NULL);
+
+	itk_lock(task);
+	if (task->itk_self != IP_NULL)
+		port = ipc_port_copy_send(task->itk_exception);
+	else
+		port = IP_NULL;
+	itk_unlock(task);
+
+	return port;
+}
+
+/*
+ *	Routine:	retrieve_thread_exception
+ *	Purpose:
+ *		Return a send right (possibly null/dead)
+ *		for the thread's exception port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_thread_exception(thread)
+	thread_t thread;
+{
+	ipc_port_t port;
+
+	assert(thread != ITH_NULL);
+
+	ith_lock(thread);
+	if (thread->ith_self != IP_NULL)
+		port = ipc_port_copy_send(thread->ith_exception);
+	else
+		port = IP_NULL;
+	ith_unlock(thread);
+
+	return port;
+}
+#endif	0
+
+/*
+ *	Routine:	mach_task_self [mach trap]
+ *	Purpose:
+ *		Give the caller send rights for his own task port.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there are any resource failures
+ *		or other errors.
+ */
+
+mach_port_t
+mach_task_self(void)
+{
+	task_t task = current_task();
+	ipc_port_t sright;
+
+	sright = retrieve_task_self_fast(task);
+	return ipc_port_copyout_send(sright, task->itk_space);
+}
+
+/*
+ *	Routine:	mach_thread_self [mach trap]
+ *	Purpose:
+ *		Give the caller send rights for his own thread port.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there are any resource failures
+ *		or other errors.
+ */
+
+mach_port_t
+mach_thread_self()
+{
+	thread_t thread = current_thread();
+	task_t task = thread->task;
+	ipc_port_t sright;
+
+	sright = retrieve_thread_self_fast(thread);
+	return ipc_port_copyout_send(sright, task->itk_space);
+}
+
+/*
+ *	Routine:	mach_reply_port [mach trap]
+ *	Purpose:
+ *		Allocate a port for the caller.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there are any resource failures
+ *		or other errors.
+ */
+
+mach_port_t
+mach_reply_port(void)
+{
+	ipc_port_t port;
+	mach_port_t name;
+	kern_return_t kr;
+
+	kr = ipc_port_alloc(current_task()->itk_space, &name, &port);
+	if (kr == KERN_SUCCESS)
+		ip_unlock(port);
+	else
+		name = MACH_PORT_NULL;
+
+	return name;
+}
+
+#if	MACH_IPC_COMPAT
+
+/*
+ *	Routine:	retrieve_task_notify
+ *	Purpose:
+ *		Return a reference (or null) for
+ *		the task's notify port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_task_notify(task)
+	task_t task;
+{
+	ipc_space_t space = task->itk_space;
+	ipc_port_t port;
+
+	is_read_lock(space);
+	if (space->is_active) {
+		port = space->is_notify;
+		if (IP_VALID(port))
+			ipc_port_reference(port);
+	} else
+		port = IP_NULL;
+	is_read_unlock(space);
+
+	return port;
+}
+
+/*
+ *	Routine:	retrieve_thread_reply
+ *	Purpose:
+ *		Return a reference (or null) for
+ *		the thread's reply port.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+retrieve_thread_reply(thread)
+	thread_t thread;
+{
+	ipc_port_t port;
+
+	ith_lock(thread);
+	if (thread->ith_self != IP_NULL) {
+		port = thread->ith_reply;
+		if (IP_VALID(port))
+			ipc_port_reference(port);
+	} else
+		port = IP_NULL;
+	ith_unlock(thread);
+
+	return port;
+}
+
+/*
+ *	Routine:	task_self [mach trap]
+ *	Purpose:
+ *		Give the caller send rights for his task port.
+ *		If new, the send right is marked with IE_BITS_COMPAT.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there are any resource failures
+ *		or other errors.
+ */
+
+port_name_t
+task_self()
+{
+	task_t task = current_task();
+	ipc_port_t sright;
+	mach_port_t name;
+
+	sright = retrieve_task_self_fast(task);
+	name = ipc_port_copyout_send_compat(sright, task->itk_space);
+	return (port_name_t) name;
+}
+
+/*
+ *	Routine:	task_notify [mach trap]
+ *	Purpose:
+ *		Give the caller the name of his own notify port.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there isn't a notify port,
+ *		if it is dead, or if the caller doesn't hold
+ *		receive rights for it.
+ */
+
+port_name_t
+task_notify()
+{
+	task_t task = current_task();
+	ipc_port_t notify;
+	mach_port_t name;
+
+	notify = retrieve_task_notify(task);
+	name = ipc_port_copyout_receiver(notify, task->itk_space);
+	return (port_name_t) name;
+}
+
+/*
+ *	Routine:	thread_self [mach trap]
+ *	Purpose:
+ *		Give the caller send rights for his own thread port.
+ *		If new, the send right is marked with IE_BITS_COMPAT.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there are any resource failures
+ *		or other errors.
+ */
+
+port_name_t
+thread_self()
+{
+	thread_t thread = current_thread();
+	task_t task = thread->task;
+	ipc_port_t sright;
+	mach_port_t name;
+
+	sright = retrieve_thread_self_fast(thread);
+	name = ipc_port_copyout_send_compat(sright, task->itk_space);
+	return (port_name_t) name;
+}
+
+/*
+ *	Routine:	thread_reply [mach trap]
+ *	Purpose:
+ *		Give the caller the name of his own reply port.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		MACH_PORT_NULL if there isn't a reply port,
+ *		if it is dead, or if the caller doesn't hold
+ *		receive rights for it.
+ */
+
+port_name_t
+thread_reply()
+{
+	task_t task = current_task();
+	thread_t thread = current_thread();
+	ipc_port_t reply;
+	mach_port_t name;
+
+	reply = retrieve_thread_reply(thread);
+	name = ipc_port_copyout_receiver(reply, task->itk_space);
+	return (port_name_t) name;
+}
+
+#endif	MACH_IPC_COMPAT
+
+/*
+ *	Routine:	task_get_special_port [kernel call]
+ *	Purpose:
+ *		Clones a send right for one of the task's
+ *		special ports.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		KERN_SUCCESS		Extracted a send right.
+ *		KERN_INVALID_ARGUMENT	The task is null.
+ *		KERN_FAILURE		The task/space is dead.
+ *		KERN_INVALID_ARGUMENT	Invalid special port.
+ */
+
+kern_return_t
+task_get_special_port(
+	task_t		task,
+	int		which,
+	ipc_port_t	*portp)
+{
+	ipc_port_t *whichp;
+	ipc_port_t port;
+
+	if (task == TASK_NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	switch (which) {
+#if	MACH_IPC_COMPAT
+	    case TASK_NOTIFY_PORT: {
+		ipc_space_t space = task->itk_space;
+
+		is_read_lock(space);
+		if (!space->is_active) {
+			is_read_unlock(space);
+			return KERN_FAILURE;
+		}
+
+		port = ipc_port_copy_send(space->is_notify);
+		is_read_unlock(space);
+
+		*portp = port;
+		return KERN_SUCCESS;
+	    }
+#endif	MACH_IPC_COMPAT
+
+	    case TASK_KERNEL_PORT:
+		whichp = &task->itk_sself;
+		break;
+
+	    case TASK_EXCEPTION_PORT:
+		whichp = &task->itk_exception;
+		break;
+
+	    case TASK_BOOTSTRAP_PORT:
+		whichp = &task->itk_bootstrap;
+		break;
+
+	    default:
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	itk_lock(task);
+	if (task->itk_self == IP_NULL) {
+		itk_unlock(task);
+		return KERN_FAILURE;
+	}
+
+	port = ipc_port_copy_send(*whichp);
+	itk_unlock(task);
+
+	*portp = port;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	Routine:	task_set_special_port [kernel call]
+ *	Purpose:
+ *		Changes one of the task's special ports,
+ *		setting it to the supplied send right.
+ *	Conditions:
+ *		Nothing locked.  If successful, consumes
+ *		the supplied send right.
+ *	Returns:
+ *		KERN_SUCCESS		Changed the special port.
+ *		KERN_INVALID_ARGUMENT	The task is null.
+ *		KERN_FAILURE		The task/space is dead.
+ *		KERN_INVALID_ARGUMENT	Invalid special port.
+ */
+
+kern_return_t
+task_set_special_port(
+	task_t		task,
+	int		which,
+	ipc_port_t	port)
+{
+	ipc_port_t *whichp;
+	ipc_port_t old;
+
+	if (task == TASK_NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	switch (which) {
+#if	MACH_IPC_COMPAT
+	    case TASK_NOTIFY_PORT: {
+		ipc_space_t space = task->itk_space;
+
+		is_write_lock(space);
+		if (!space->is_active) {
+			is_write_unlock(space);
+			return KERN_FAILURE;
+		}
+
+		old = space->is_notify;
+		space->is_notify = port;
+		is_write_unlock(space);
+
+		if (IP_VALID(old))
+			ipc_port_release_send(old);
+		return KERN_SUCCESS;
+	    }
+#endif	MACH_IPC_COMPAT
+
+	    case TASK_KERNEL_PORT:
+		whichp = &task->itk_sself;
+		break;
+
+	    case TASK_EXCEPTION_PORT:
+		whichp = &task->itk_exception;
+		break;
+
+	    case TASK_BOOTSTRAP_PORT:
+		whichp = &task->itk_bootstrap;
+		break;
+
+	    default:
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	itk_lock(task);
+	if (task->itk_self == IP_NULL) {
+		itk_unlock(task);
+		return KERN_FAILURE;
+	}
+
+	old = *whichp;
+	*whichp = port;
+	itk_unlock(task);
+
+	if (IP_VALID(old))
+		ipc_port_release_send(old);
+	return KERN_SUCCESS;
+}
+
+/*
+ *	Routine:	thread_get_special_port [kernel call]
+ *	Purpose:
+ *		Clones a send right for one of the thread's
+ *		special ports.
+ *	Conditions:
+ *		Nothing locked.
+ *	Returns:
+ *		KERN_SUCCESS		Extracted a send right.
+ *		KERN_INVALID_ARGUMENT	The thread is null.
+ *		KERN_FAILURE		The thread is dead.
+ *		KERN_INVALID_ARGUMENT	Invalid special port.
+ */
+
+kern_return_t
+thread_get_special_port(thread, which, portp)
+	thread_t thread;
+	int which;
+	ipc_port_t *portp;
+{
+	ipc_port_t *whichp;
+	ipc_port_t port;
+
+	if (thread == ITH_NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	switch (which) {
+#if	MACH_IPC_COMPAT
+	    case THREAD_REPLY_PORT:
+		whichp = &thread->ith_reply;
+		break;
+#endif	MACH_IPC_COMPAT
+
+	    case THREAD_KERNEL_PORT:
+		whichp = &thread->ith_sself;
+		break;
+
+	    case THREAD_EXCEPTION_PORT:
+		whichp = &thread->ith_exception;
+		break;
+
+	    default:
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	ith_lock(thread);
+	if (thread->ith_self == IP_NULL) {
+		ith_unlock(thread);
+		return KERN_FAILURE;
+	}
+
+	port = ipc_port_copy_send(*whichp);
+	ith_unlock(thread);
+
+	*portp = port;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	Routine:	thread_set_special_port [kernel call]
+ *	Purpose:
+ *		Changes one of the thread's special ports,
+ *		setting it to the supplied send right.
+ *	Conditions:
+ *		Nothing locked.  If successful, consumes
+ *		the supplied send right.
+ *	Returns:
+ *		KERN_SUCCESS		Changed the special port.
+ *		KERN_INVALID_ARGUMENT	The thread is null.
+ *		KERN_FAILURE		The thread is dead.
+ *		KERN_INVALID_ARGUMENT	Invalid special port.
+ */
+
+kern_return_t
+thread_set_special_port(thread, which, port)
+	thread_t thread;
+	int which;
+	ipc_port_t port;
+{
+	ipc_port_t *whichp;
+	ipc_port_t old;
+
+	if (thread == ITH_NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	switch (which) {
+#if	MACH_IPC_COMPAT
+	    case THREAD_REPLY_PORT:
+		whichp = &thread->ith_reply;
+		break;
+#endif	MACH_IPC_COMPAT
+
+	    case THREAD_KERNEL_PORT:
+		whichp = &thread->ith_sself;
+		break;
+
+	    case THREAD_EXCEPTION_PORT:
+		whichp = &thread->ith_exception;
+		break;
+
+	    default:
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	ith_lock(thread);
+	if (thread->ith_self == IP_NULL) {
+		ith_unlock(thread);
+		return KERN_FAILURE;
+	}
+
+	old = *whichp;
+	*whichp = port;
+	ith_unlock(thread);
+
+	if (IP_VALID(old))
+		ipc_port_release_send(old);
+	return KERN_SUCCESS;
+}
+
+/*
+ *	Routine:	mach_ports_register [kernel call]
+ *	Purpose:
+ *		Stash a handful of port send rights in the task.
+ *		Child tasks will inherit these rights, but they
+ *		must use mach_ports_lookup to acquire them.
+ *
+ *		The rights are supplied in a (wired) kalloc'd segment.
+ *		Rights which aren't supplied are assumed to be null.
+ *	Conditions:
+ *		Nothing locked.  If successful, consumes
+ *		the supplied rights and memory.
+ *	Returns:
+ *		KERN_SUCCESS		Stashed the port rights.
+ *		KERN_INVALID_ARGUMENT	The task is null.
+ *		KERN_INVALID_ARGUMENT	The task is dead.
+ *		KERN_INVALID_ARGUMENT	Too many port rights supplied.
+ */
+
+kern_return_t
+mach_ports_register(
+	task_t			task,
+	mach_port_array_t	memory,
+	mach_msg_type_number_t	portsCnt)
+{
+	ipc_port_t ports[TASK_PORT_REGISTER_MAX];
+	int i;
+
+	if ((task == TASK_NULL) ||
+	    (portsCnt > TASK_PORT_REGISTER_MAX))
+		return KERN_INVALID_ARGUMENT;
+
+	/*
+	 *	Pad the port rights with nulls.
+	 */
+
+	for (i = 0; i < portsCnt; i++)
+		ports[i] = memory[i];
+	for (; i < TASK_PORT_REGISTER_MAX; i++)
+		ports[i] = IP_NULL;
+
+	itk_lock(task);
+	if (task->itk_self == IP_NULL) {
+		itk_unlock(task);
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	/*
+	 *	Replace the old send rights with the new.
+	 *	Release the old rights after unlocking.
+	 */
+
+	for (i = 0; i < TASK_PORT_REGISTER_MAX; i++) {
+		ipc_port_t old;
+
+		old = task->itk_registered[i];
+		task->itk_registered[i] = ports[i];
+		ports[i] = old;
+	}
+
+	itk_unlock(task);
+
+	for (i = 0; i < TASK_PORT_REGISTER_MAX; i++)
+		if (IP_VALID(ports[i]))
+			ipc_port_release_send(ports[i]);
+
+	/*
+	 *	Now that the operation is known to be successful,
+	 *	we can free the memory.
+	 */
+
+	if (portsCnt != 0)
+		kfree((vm_offset_t) memory,
+		      (vm_size_t) (portsCnt * sizeof(mach_port_t)));
+
+	return KERN_SUCCESS;
+}
+
+/*
+ *	Routine:	mach_ports_lookup [kernel call]
+ *	Purpose:
+ *		Retrieves (clones) the stashed port send rights.
+ *	Conditions:
+ *		Nothing locked.  If successful, the caller gets
+ *		rights and memory.
+ *	Returns:
+ *		KERN_SUCCESS		Retrieved the send rights.
+ *		KERN_INVALID_ARGUMENT	The task is null.
+ *		KERN_INVALID_ARGUMENT	The task is dead.
+ *		KERN_RESOURCE_SHORTAGE	Couldn't allocate memory.
+ */
+
+kern_return_t
+mach_ports_lookup(task, portsp, portsCnt)
+	task_t task;
+	ipc_port_t **portsp;
+	mach_msg_type_number_t *portsCnt;
+{
+	vm_offset_t memory;
+	vm_size_t size;
+	ipc_port_t *ports;
+	int i;
+
+	if (task == TASK_NULL)
+		return KERN_INVALID_ARGUMENT;
+
+	size = (vm_size_t) (TASK_PORT_REGISTER_MAX * sizeof(ipc_port_t));
+
+	memory = kalloc(size);
+	if (memory == 0)
+		return KERN_RESOURCE_SHORTAGE;
+
+	itk_lock(task);
+	if (task->itk_self == IP_NULL) {
+		itk_unlock(task);
+
+		kfree(memory, size);
+		return KERN_INVALID_ARGUMENT;
+	}
+
+	ports = (ipc_port_t *) memory;
+
+	/*
+	 *	Clone port rights.  Because kalloc'd memory
+	 *	is wired, we won't fault while holding the task lock.
+	 */
+
+	for (i = 0; i < TASK_PORT_REGISTER_MAX; i++)
+		ports[i] = ipc_port_copy_send(task->itk_registered[i]);
+
+	itk_unlock(task);
+
+	*portsp = (mach_port_array_t) ports;
+	*portsCnt = TASK_PORT_REGISTER_MAX;
+	return KERN_SUCCESS;
+}
+
+/*
+ *	Routine:	convert_port_to_task
+ *	Purpose:
+ *		Convert from a port to a task.
+ *		Doesn't consume the port ref; produces a task ref,
+ *		which may be null.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+task_t
+convert_port_to_task(
+	ipc_port_t	port)
+{
+	task_t task = TASK_NULL;
+
+	if (IP_VALID(port)) {
+		ip_lock(port);
+		if (ip_active(port) &&
+		    (ip_kotype(port) == IKOT_TASK)) {
+			task = (task_t) port->ip_kobject;
+			task_reference(task);
+		}
+		ip_unlock(port);
+	}
+
+	return task;
+}
+
+/*
+ *	Routine:	convert_port_to_space
+ *	Purpose:
+ *		Convert from a port to a space.
+ *		Doesn't consume the port ref; produces a space ref,
+ *		which may be null.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_space_t
+convert_port_to_space(
+	ipc_port_t	port)
+{
+	ipc_space_t space = IS_NULL;
+
+	if (IP_VALID(port)) {
+		ip_lock(port);
+		if (ip_active(port) &&
+		    (ip_kotype(port) == IKOT_TASK)) {
+			space = ((task_t) port->ip_kobject)->itk_space;
+			is_reference(space);
+		}
+		ip_unlock(port);
+	}
+
+	return space;
+}
+
+/*
+ *	Routine:	convert_port_to_map
+ *	Purpose:
+ *		Convert from a port to a map.
+ *		Doesn't consume the port ref; produces a map ref,
+ *		which may be null.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+vm_map_t
+convert_port_to_map(port)
+	ipc_port_t port;
+{
+	vm_map_t map = VM_MAP_NULL;
+
+	if (IP_VALID(port)) {
+		ip_lock(port);
+		if (ip_active(port) &&
+		    (ip_kotype(port) == IKOT_TASK)) {
+			map = ((task_t) port->ip_kobject)->map;
+			vm_map_reference(map);
+		}
+		ip_unlock(port);
+	}
+
+	return map;
+}
+
+/*
+ *	Routine:	convert_port_to_thread
+ *	Purpose:
+ *		Convert from a port to a thread.
+ *		Doesn't consume the port ref; produces a thread ref,
+ *		which may be null.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+thread_t
+convert_port_to_thread(port)
+	ipc_port_t port;
+{
+	thread_t thread = THREAD_NULL;
+
+	if (IP_VALID(port)) {
+		ip_lock(port);
+		if (ip_active(port) &&
+		    (ip_kotype(port) == IKOT_THREAD)) {
+			thread = (thread_t) port->ip_kobject;
+			thread_reference(thread);
+		}
+		ip_unlock(port);
+	}
+
+	return thread;
+}
+
+/*
+ *	Routine:	convert_task_to_port
+ *	Purpose:
+ *		Convert from a task to a port.
+ *		Consumes a task ref; produces a naked send right
+ *		which may be invalid.  
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+convert_task_to_port(task)
+	task_t task;
+{
+	ipc_port_t port;
+
+	itk_lock(task);
+	if (task->itk_self != IP_NULL)
+		port = ipc_port_make_send(task->itk_self);
+	else
+		port = IP_NULL;
+	itk_unlock(task);
+
+	task_deallocate(task);
+	return port;
+}
+
+/*
+ *	Routine:	convert_thread_to_port
+ *	Purpose:
+ *		Convert from a thread to a port.
+ *		Consumes a thread ref; produces a naked send right
+ *		which may be invalid.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+ipc_port_t
+convert_thread_to_port(thread)
+	thread_t thread;
+{
+	ipc_port_t port;
+
+	ith_lock(thread);
+	if (thread->ith_self != IP_NULL)
+		port = ipc_port_make_send(thread->ith_self);
+	else
+		port = IP_NULL;
+	ith_unlock(thread);
+
+	thread_deallocate(thread);
+	return port;
+}
+
+/*
+ *	Routine:	space_deallocate
+ *	Purpose:
+ *		Deallocate a space ref produced by convert_port_to_space.
+ *	Conditions:
+ *		Nothing locked.
+ */
+
+void
+space_deallocate(space)
+	ipc_space_t space;
+{
+	if (space != IS_NULL)
+		is_release(space);
+}