[apple/xnu.git] / osfmk / ipc / ipc_object.c

/*
 * Copyright (c) 2000-2004 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
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * 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
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/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989 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/ipc_object.c
 *      Author: Rich Draves
 *      Date:   1989
 *
 *      Functions to manipulate IPC objects.
 */

#include <mach_rt.h>

#include <mach/mach_types.h>
#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/port.h>
#include <mach/message.h>

#include <kern/kern_types.h>
#include <kern/misc_protos.h>

#include <ipc/ipc_types.h>
#include <ipc/port.h>
#include <ipc/ipc_space.h>
#include <ipc/ipc_entry.h>
#include <ipc/ipc_object.h>
#include <ipc/ipc_hash.h>
#include <ipc/ipc_right.h>
#include <ipc/ipc_notify.h>
#include <ipc/ipc_pset.h>

zone_t ipc_object_zones[IOT_NUMBER];

/*
 *      Routine:        ipc_object_reference
 *      Purpose:
 *              Take a reference to an object.
 */

void
ipc_object_reference(
        ipc_object_t    object)
{
        io_lock(object);
        assert(object->io_references > 0);
        io_reference(object);
        io_unlock(object);
}

/*
 *      Routine:        ipc_object_release
 *      Purpose:
 *              Release a reference to an object.
 */

void
ipc_object_release(
        ipc_object_t    object)
{
        io_lock(object);
        assert(object->io_references > 0);
        io_release(object);
        io_check_unlock(object);
}

/*
 *      Routine:        ipc_object_translate
 *      Purpose:
 *              Look up an object in a space.
 *      Conditions:
 *              Nothing locked before.  If successful, the object
 *              is returned locked.  The caller doesn't get a ref.
 *      Returns:
 *              KERN_SUCCESS            Object returned locked.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_INVALID_NAME       The name doesn't denote a right.
 *              KERN_INVALID_RIGHT      Name doesn't denote the correct right.
 */

kern_return_t
ipc_object_translate(
        ipc_space_t             space,
        mach_port_name_t        name,
        mach_port_right_t       right,
        ipc_object_t            *objectp)
{
        ipc_entry_t entry;
        ipc_object_t object;
        kern_return_t kr;

        kr = ipc_right_lookup_read(space, name, &entry);
        if (kr != KERN_SUCCESS)
                return kr;
        /* space is read-locked and active */

        if ((entry->ie_bits & MACH_PORT_TYPE(right)) == MACH_PORT_TYPE_NONE) {
                is_read_unlock(space);
                return KERN_INVALID_RIGHT;
        }

        object = entry->ie_object;
        assert(object != IO_NULL);

        io_lock(object);
        is_read_unlock(space);

        *objectp = object;
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_object_translate_two
 *      Purpose:
 *              Look up two objects in a space.
 *      Conditions:
 *              Nothing locked before.  If successful, the objects
 *              are returned locked.  The caller doesn't get a ref.
 *      Returns:
 *              KERN_SUCCESS            Objects returned locked.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_INVALID_NAME       A name doesn't denote a right.
 *              KERN_INVALID_RIGHT      A name doesn't denote the correct right.
 */

kern_return_t
ipc_object_translate_two(
        ipc_space_t             space,
        mach_port_name_t        name1,
        mach_port_right_t       right1,
        ipc_object_t            *objectp1,
        mach_port_name_t        name2,
        mach_port_right_t       right2,
        ipc_object_t            *objectp2)
{
        ipc_entry_t entry1;
        ipc_entry_t entry2;
        ipc_object_t object;
        kern_return_t kr;

        kr = ipc_right_lookup_two_read(space, name1, &entry1, name2, &entry2);
        if (kr != KERN_SUCCESS)
                return kr;
        /* space is read-locked and active */

        if ((entry1->ie_bits & MACH_PORT_TYPE(right1)) == MACH_PORT_TYPE_NONE) {
                is_read_unlock(space);
                return KERN_INVALID_RIGHT;
        }

        if ((entry2->ie_bits & MACH_PORT_TYPE(right2)) == MACH_PORT_TYPE_NONE) {
                is_read_unlock(space);
                return KERN_INVALID_RIGHT;
        }

        object = entry1->ie_object;
        assert(object != IO_NULL);
        io_lock(object);
        *objectp1 = object;

        object = entry2->ie_object;
        assert(object != IO_NULL);
        io_lock(object);
        *objectp2 = object;

        is_read_unlock(space);
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_object_alloc_dead
 *      Purpose:
 *              Allocate a dead-name entry.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            The dead name is allocated.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_NO_SPACE           No room for an entry in the space.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
ipc_object_alloc_dead(
        ipc_space_t             space,
        mach_port_name_t        *namep)
{
        ipc_entry_t entry;
        kern_return_t kr;

        kr = ipc_entry_alloc(space, namep, &entry);
        if (kr != KERN_SUCCESS)
                return kr;
        /* space is write-locked */

        /* null object, MACH_PORT_TYPE_DEAD_NAME, 1 uref */

        assert(entry->ie_object == IO_NULL);
        entry->ie_bits |= MACH_PORT_TYPE_DEAD_NAME | 1;
        
        is_write_unlock(space);
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_object_alloc_dead_name
 *      Purpose:
 *              Allocate a dead-name entry, with a specific name.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            The dead name is allocated.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_NAME_EXISTS        The name already denotes a right.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
ipc_object_alloc_dead_name(
        ipc_space_t             space,
        mach_port_name_t        name)
{
        ipc_entry_t entry;
        kern_return_t kr;

        kr = ipc_entry_alloc_name(space, name, &entry);
        if (kr != KERN_SUCCESS)
                return kr;
        /* space is write-locked */

        if (ipc_right_inuse(space, name, entry))
                return KERN_NAME_EXISTS;

        /* null object, MACH_PORT_TYPE_DEAD_NAME, 1 uref */

        assert(entry->ie_object == IO_NULL);
        entry->ie_bits |= MACH_PORT_TYPE_DEAD_NAME | 1;

        is_write_unlock(space);
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_object_alloc
 *      Purpose:
 *              Allocate an object.
 *      Conditions:
 *              Nothing locked.  If successful, the object is returned locked.
 *              The caller doesn't get a reference for the object.
 *      Returns:
 *              KERN_SUCCESS            The object is allocated.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_NO_SPACE           No room for an entry in the space.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
ipc_object_alloc(
        ipc_space_t             space,
        ipc_object_type_t       otype,
        mach_port_type_t        type,
        mach_port_urefs_t       urefs,
        mach_port_name_t        *namep,
        ipc_object_t            *objectp)
{
        ipc_object_t object;
        ipc_entry_t entry;
        kern_return_t kr;

        assert(otype < IOT_NUMBER);
        assert((type & MACH_PORT_TYPE_ALL_RIGHTS) == type);
        assert(type != MACH_PORT_TYPE_NONE);
        assert(urefs <= MACH_PORT_UREFS_MAX);

        object = io_alloc(otype);
        if (object == IO_NULL)
                return KERN_RESOURCE_SHORTAGE;

        if (otype == IOT_PORT) {
                ipc_port_t port = (ipc_port_t)object;

                bzero((char *)port, sizeof(*port));
        } else if (otype == IOT_PORT_SET) {
                ipc_pset_t pset = (ipc_pset_t)object;

                bzero((char *)pset, sizeof(*pset));
        }

        io_lock_init(object);
        *namep = (mach_port_name_t)object;
        kr = ipc_entry_alloc(space, namep, &entry);
        if (kr != KERN_SUCCESS) {
                io_free(otype, object);
                return kr;
        }
        /* space is write-locked */

        entry->ie_bits |= type | urefs;
        entry->ie_object = object;

        io_lock(object);
        is_write_unlock(space);

        object->io_references = 1; /* for entry, not caller */
        object->io_bits = io_makebits(TRUE, otype, 0);

        *objectp = object;
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_object_alloc_name
 *      Purpose:
 *              Allocate an object, with a specific name.
 *      Conditions:
 *              Nothing locked.  If successful, the object is returned locked.
 *              The caller doesn't get a reference for the object.
 *      Returns:
 *              KERN_SUCCESS            The object is allocated.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_NAME_EXISTS        The name already denotes a right.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate memory.
 */

kern_return_t
ipc_object_alloc_name(
        ipc_space_t             space,
        ipc_object_type_t       otype,
        mach_port_type_t        type,
        mach_port_urefs_t       urefs,
        mach_port_name_t        name,
        ipc_object_t            *objectp)
{
        ipc_object_t object;
        ipc_entry_t entry;
        kern_return_t kr;

        assert(otype < IOT_NUMBER);
        assert((type & MACH_PORT_TYPE_ALL_RIGHTS) == type);
        assert(type != MACH_PORT_TYPE_NONE);
        assert(urefs <= MACH_PORT_UREFS_MAX);

        object = io_alloc(otype);
        if (object == IO_NULL)
                return KERN_RESOURCE_SHORTAGE;

        if (otype == IOT_PORT) {
                ipc_port_t port = (ipc_port_t)object;

                bzero((char *)port, sizeof(*port));
        } else if (otype == IOT_PORT_SET) {
                ipc_pset_t pset = (ipc_pset_t)object;

                bzero((char *)pset, sizeof(*pset));
        }

        io_lock_init(object);
        kr = ipc_entry_alloc_name(space, name, &entry);
        if (kr != KERN_SUCCESS) {
                io_free(otype, object);
                return kr;
        }
        /* space is write-locked */

        if (ipc_right_inuse(space, name, entry)) {
                io_free(otype, object);
                return KERN_NAME_EXISTS;
        }

        entry->ie_bits |= type | urefs;
        entry->ie_object = object;

        io_lock(object);
        is_write_unlock(space);

        object->io_references = 1; /* for entry, not caller */
        object->io_bits = io_makebits(TRUE, otype, 0);

        *objectp = object;
        return KERN_SUCCESS;
}

/*
 *      Routine:        ipc_object_copyin_type
 *      Purpose:
 *              Convert a send type name to a received type name.
 */

mach_msg_type_name_t
ipc_object_copyin_type(
        mach_msg_type_name_t    msgt_name)
{
        switch (msgt_name) {

            case MACH_MSG_TYPE_MOVE_RECEIVE:
            case MACH_MSG_TYPE_COPY_RECEIVE:
                return MACH_MSG_TYPE_PORT_RECEIVE;

            case MACH_MSG_TYPE_MOVE_SEND_ONCE:
            case MACH_MSG_TYPE_MAKE_SEND_ONCE:
                return MACH_MSG_TYPE_PORT_SEND_ONCE;

            case MACH_MSG_TYPE_MOVE_SEND:
            case MACH_MSG_TYPE_MAKE_SEND:
            case MACH_MSG_TYPE_COPY_SEND:
                return MACH_MSG_TYPE_PORT_SEND;

            default:
                return MACH_MSG_TYPE_PORT_NONE;
        }
}

/*
 *      Routine:        ipc_object_copyin
 *      Purpose:
 *              Copyin a capability from a space.
 *              If successful, the caller gets a ref
 *              for the resulting object, unless it is IO_DEAD.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Acquired an object, possibly IO_DEAD.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_INVALID_NAME       Name doesn't exist in space.
 *              KERN_INVALID_RIGHT      Name doesn't denote correct right.
 */

kern_return_t
ipc_object_copyin(
        ipc_space_t             space,
        mach_port_name_t        name,
        mach_msg_type_name_t    msgt_name,
        ipc_object_t            *objectp)
{
        ipc_entry_t entry;
        ipc_port_t soright;
        kern_return_t kr;

        /*
         *      Could first try a read lock when doing
         *      MACH_MSG_TYPE_COPY_SEND, MACH_MSG_TYPE_MAKE_SEND,
         *      and MACH_MSG_TYPE_MAKE_SEND_ONCE.
         */

        kr = ipc_right_lookup_write(space, name, &entry);
        if (kr != KERN_SUCCESS)
                return kr;
        /* space is write-locked and active */

        kr = ipc_right_copyin(space, name, entry,
                              msgt_name, TRUE,
                              objectp, &soright);
        if (IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE)
                ipc_entry_dealloc(space, name, entry);
        is_write_unlock(space);

        if ((kr == KERN_SUCCESS) && (soright != IP_NULL))
                ipc_notify_port_deleted(soright, name);

        return kr;
}

/*
 *      Routine:        ipc_object_copyin_from_kernel
 *      Purpose:
 *              Copyin a naked capability from the kernel.
 *
 *              MACH_MSG_TYPE_MOVE_RECEIVE
 *                      The receiver must be ipc_space_kernel
 *                      or the receive right must already be in limbo.
 *                      Consumes the naked receive right.
 *              MACH_MSG_TYPE_COPY_SEND
 *                      A naked send right must be supplied.
 *                      The port gains a reference, and a send right
 *                      if the port is still active.
 *              MACH_MSG_TYPE_MAKE_SEND
 *                      The receiver must be ipc_space_kernel.
 *                      The port gains a reference and a send right.
 *              MACH_MSG_TYPE_MOVE_SEND
 *                      Consumes a naked send right.
 *              MACH_MSG_TYPE_MAKE_SEND_ONCE
 *                      The port gains a reference and a send-once right.
 *                      Receiver also be the caller of device subsystem,
 *                      so no assertion.
 *              MACH_MSG_TYPE_MOVE_SEND_ONCE
 *                      Consumes a naked send-once right.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_object_copyin_from_kernel(
        ipc_object_t            object,
        mach_msg_type_name_t    msgt_name)
{
        assert(IO_VALID(object));

        switch (msgt_name) {
            case MACH_MSG_TYPE_MOVE_RECEIVE: {
                ipc_port_t port = (ipc_port_t) object;

                ip_lock(port);
                assert(ip_active(port));
                if (port->ip_destination != IP_NULL) {
                        assert(port->ip_receiver == ipc_space_kernel);

                        /* relevant part of ipc_port_clear_receiver */
                        ipc_port_set_mscount(port, 0);

                        port->ip_receiver_name = MACH_PORT_NULL;
                        port->ip_destination = IP_NULL;
                }
                ip_unlock(port);
                break;
            }

            case MACH_MSG_TYPE_COPY_SEND: {
                ipc_port_t port = (ipc_port_t) object;

                ip_lock(port);
                if (ip_active(port)) {
                        assert(port->ip_srights > 0);
                        port->ip_srights++;
                }
                ip_reference(port);
                ip_unlock(port);
                break;
            }

            case MACH_MSG_TYPE_MAKE_SEND: {
                ipc_port_t port = (ipc_port_t) object;

                ip_lock(port);
                assert(ip_active(port));
                assert(port->ip_receiver_name != MACH_PORT_NULL);
                assert(port->ip_receiver == ipc_space_kernel);

                ip_reference(port);
                port->ip_mscount++;
                port->ip_srights++;
                ip_unlock(port);
                break;
            }

            case MACH_MSG_TYPE_MOVE_SEND: {
                /* move naked send right into the message */
                assert(((ipc_port_t)object)->ip_srights);
                break;
            }

            case MACH_MSG_TYPE_MAKE_SEND_ONCE: {
                ipc_port_t port = (ipc_port_t) object;

                ip_lock(port);
                assert(ip_active(port));
                assert(port->ip_receiver_name != MACH_PORT_NULL);

                ip_reference(port);
                port->ip_sorights++;
                ip_unlock(port);
                break;
            }

            case MACH_MSG_TYPE_MOVE_SEND_ONCE: {
                /* move naked send-once right into the message */
                assert(((ipc_port_t)object)->ip_sorights);
                break;
            }

            default:
                panic("ipc_object_copyin_from_kernel: strange rights");
        }
}

/*
 *      Routine:        ipc_object_destroy
 *      Purpose:
 *              Destroys a naked capability.
 *              Consumes a ref for the object.
 *
 *              A receive right should be in limbo or in transit.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_object_destroy(
        ipc_object_t            object,
        mach_msg_type_name_t    msgt_name)
{
        assert(IO_VALID(object));
        assert(io_otype(object) == IOT_PORT);

        switch (msgt_name) {
            case MACH_MSG_TYPE_PORT_SEND:
                ipc_port_release_send((ipc_port_t) object);
                break;

            case MACH_MSG_TYPE_PORT_SEND_ONCE:
                ipc_notify_send_once((ipc_port_t) object);
                break;

            case MACH_MSG_TYPE_PORT_RECEIVE:
                ipc_port_release_receive((ipc_port_t) object);
                break;

            default:
                panic("ipc_object_destroy: strange rights");
        }
}

/*
 *      Routine:        ipc_object_copyout
 *      Purpose:
 *              Copyout a capability, placing it into a space.
 *              If successful, consumes a ref for the object.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Copied out object, consumed ref.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_INVALID_CAPABILITY The object is dead.
 *              KERN_NO_SPACE           No room in space for another right.
 *              KERN_RESOURCE_SHORTAGE  No memory available.
 *              KERN_UREFS_OVERFLOW     Urefs limit exceeded
 *                      and overflow wasn't specified.
 */

kern_return_t
ipc_object_copyout(
        ipc_space_t             space,
        ipc_object_t            object,
        mach_msg_type_name_t    msgt_name,
        boolean_t               overflow,
        mach_port_name_t        *namep)
{
        mach_port_name_t name;
        ipc_entry_t entry;
        kern_return_t kr;

        assert(IO_VALID(object));
        assert(io_otype(object) == IOT_PORT);

        is_write_lock(space);

        for (;;) {
                if (!space->is_active) {
                        is_write_unlock(space);
                        return KERN_INVALID_TASK;
                }

                if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
                    ipc_right_reverse(space, object, &name, &entry)) { 
                        /* object is locked and active */

                        assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
                        break;
                }

                name = (mach_port_name_t)object;
                kr = ipc_entry_get(space, &name, &entry);
                if (kr != KERN_SUCCESS) {
                        /* unlocks/locks space, so must start again */

                        kr = ipc_entry_grow_table(space, ITS_SIZE_NONE);
                        if (kr != KERN_SUCCESS)
                                return kr; /* space is unlocked */

                        continue;
                }

                assert(IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE);
                assert(entry->ie_object == IO_NULL);

                io_lock(object);
                if (!io_active(object)) {
                        io_unlock(object);
                        ipc_entry_dealloc(space, name, entry);
                        is_write_unlock(space);
                        return KERN_INVALID_CAPABILITY;
                }

                entry->ie_object = object;
                break;
        }

        /* space is write-locked and active, object is locked and active */

        kr = ipc_right_copyout(space, name, entry,
                               msgt_name, overflow, object);
        /* object is unlocked */
        is_write_unlock(space);

        if (kr == KERN_SUCCESS)
                *namep = name;
        return kr;
}

/*
 *      Routine:        ipc_object_copyout_name
 *      Purpose:
 *              Copyout a capability, placing it into a space.
 *              The specified name is used for the capability.
 *              If successful, consumes a ref for the object.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Copied out object, consumed ref.
 *              KERN_INVALID_TASK       The space is dead.
 *              KERN_INVALID_CAPABILITY The object is dead.
 *              KERN_RESOURCE_SHORTAGE  No memory available.
 *              KERN_UREFS_OVERFLOW     Urefs limit exceeded
 *                      and overflow wasn't specified.
 *              KERN_RIGHT_EXISTS       Space has rights under another name.
 *              KERN_NAME_EXISTS        Name is already used.
 */

kern_return_t
ipc_object_copyout_name(
        ipc_space_t             space,
        ipc_object_t            object,
        mach_msg_type_name_t    msgt_name,
        boolean_t               overflow,
        mach_port_name_t        name)
{
        mach_port_name_t oname;
        ipc_entry_t oentry;
        ipc_entry_t entry;
        kern_return_t kr;

        assert(IO_VALID(object));
        assert(io_otype(object) == IOT_PORT);

        kr = ipc_entry_alloc_name(space, name, &entry);
        if (kr != KERN_SUCCESS)
                return kr;
        /* space is write-locked and active */

        if ((msgt_name != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
            ipc_right_reverse(space, object, &oname, &oentry)) {
                /* object is locked and active */

                if (name != oname) {
                        io_unlock(object);

                        if (IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE)
                                ipc_entry_dealloc(space, name, entry);

                        is_write_unlock(space);
                        return KERN_RIGHT_EXISTS;
                }

                assert(entry == oentry);
                assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
        } else {
                if (ipc_right_inuse(space, name, entry))
                        return KERN_NAME_EXISTS;

                assert(IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE);
                assert(entry->ie_object == IO_NULL);

                io_lock(object);
                if (!io_active(object)) {
                        io_unlock(object);
                        ipc_entry_dealloc(space, name, entry);
                        is_write_unlock(space);
                        return KERN_INVALID_CAPABILITY;
                }

                entry->ie_object = object;
        }

        /* space is write-locked and active, object is locked and active */

        kr = ipc_right_copyout(space, name, entry,
                               msgt_name, overflow, object);
        /* object is unlocked */
        is_write_unlock(space);
        return kr;
}

/*
 *      Routine:        ipc_object_copyout_dest
 *      Purpose:
 *              Translates/consumes the destination right of a message.
 *              This is unlike normal copyout because the right is consumed
 *              in a funny way instead of being given to the receiving space.
 *              The receiver gets his name for the port, if he has receive
 *              rights, otherwise MACH_PORT_NULL.
 *      Conditions:
 *              The object is locked and active.  Nothing else locked.
 *              The object is unlocked and loses a reference.
 */

void
ipc_object_copyout_dest(
        ipc_space_t             space,
        ipc_object_t            object,
        mach_msg_type_name_t    msgt_name,
        mach_port_name_t        *namep)
{
        mach_port_name_t name;

        assert(IO_VALID(object));
        assert(io_active(object));

        io_release(object);

        /*
         *      If the space is the receiver/owner of the object,
         *      then we quietly consume the right and return
         *      the space's name for the object.  Otherwise
         *      we destroy the right and return MACH_PORT_NULL.
         */

        switch (msgt_name) {
            case MACH_MSG_TYPE_PORT_SEND: {
                ipc_port_t port = (ipc_port_t) object;
                ipc_port_t nsrequest = IP_NULL;
                mach_port_mscount_t mscount;

                if (port->ip_receiver == space)
                        name = port->ip_receiver_name;
                else
                        name = MACH_PORT_NULL;

                assert(port->ip_srights > 0);
                if (--port->ip_srights == 0 &&
                    port->ip_nsrequest != IP_NULL) {
                        nsrequest = port->ip_nsrequest;
                        port->ip_nsrequest = IP_NULL;
                        mscount = port->ip_mscount;
                        ip_unlock(port);
                        ipc_notify_no_senders(nsrequest, mscount);
                } else
                        ip_unlock(port);
                break;
            }

            case MACH_MSG_TYPE_PORT_SEND_ONCE: {
                ipc_port_t port = (ipc_port_t) object;

                assert(port->ip_sorights > 0);

                if (port->ip_receiver == space) {
                        /* quietly consume the send-once right */

                        port->ip_sorights--;
                        name = port->ip_receiver_name;
                        ip_unlock(port);
                } else {
                        /*
                         *      A very bizarre case.  The message
                         *      was received, but before this copyout
                         *      happened the space lost receive rights.
                         *      We can't quietly consume the soright
                         *      out from underneath some other task,
                         *      so generate a send-once notification.
                         */

                        ip_reference(port); /* restore ref */
                        ip_unlock(port);

                        ipc_notify_send_once(port);
                        name = MACH_PORT_NULL;
                }

                break;
            }

            default:
                panic("ipc_object_copyout_dest: strange rights");
                name = MACH_PORT_DEAD;
        }

        *namep = name;
}

/*
 *      Routine:        ipc_object_rename
 *      Purpose:
 *              Rename an entry in a space.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              KERN_SUCCESS            Renamed the entry.
 *              KERN_INVALID_TASK       The space was dead.
 *              KERN_INVALID_NAME       oname didn't denote an entry.
 *              KERN_NAME_EXISTS        nname already denoted an entry.
 *              KERN_RESOURCE_SHORTAGE  Couldn't allocate new entry.
 */

kern_return_t
ipc_object_rename(
        ipc_space_t             space,
        mach_port_name_t        oname,
        mach_port_name_t        nname)
{
        ipc_entry_t oentry, nentry;
        kern_return_t kr;
        
        kr = ipc_entry_alloc_name(space, nname, &nentry);
        if (kr != KERN_SUCCESS)
                return kr;

        /* space is write-locked and active */

        if (ipc_right_inuse(space, nname, nentry)) {
                /* space is unlocked */
                return KERN_NAME_EXISTS;
        }

        /* don't let ipc_entry_lookup see the uninitialized new entry */

        if ((oname == nname) ||
            ((oentry = ipc_entry_lookup(space, oname)) == IE_NULL)) {
                ipc_entry_dealloc(space, nname, nentry);
                is_write_unlock(space);
                return KERN_INVALID_NAME;
        }

        kr = ipc_right_rename(space, oname, oentry, nname, nentry);
        /* space is unlocked */
        return kr;
}

#if     MACH_ASSERT
/*
 *      Check whether the object is a port if so, free it.  But
 *      keep track of that fact.
 */
void
io_free(
        unsigned int    otype,
        ipc_object_t    object)
{
        ipc_port_t      port;

        if (otype == IOT_PORT) {
                port = (ipc_port_t) object;
#if     MACH_ASSERT
                ipc_port_track_dealloc(port);
#endif  /* MACH_ASSERT */
        }
        zfree(ipc_object_zones[otype], object);
}
#endif  /* MACH_ASSERT */

#include <mach_kdb.h>
#if     MACH_KDB

#include <ddb/db_output.h>
#include <kern/ipc_kobject.h>

#define printf  kdbprintf 

/*
 *      Routine:        ipc_object_print
 *      Purpose:
 *              Pretty-print an object for kdb.
 */

const char *ikot_print_array[IKOT_MAX_TYPE] = {
        "(NONE)             ",
        "(THREAD)           ",
        "(TASK)             ",
        "(HOST)             ",
        "(HOST_PRIV)        ",
        "(PROCESSOR)        ",
        "(PSET)             ",
        "(PSET_NAME)        ",
        "(TIMER)            ",
        "(PAGER_REQUEST)    ",
        "(DEVICE)           ",  /* 10 */
        "(XMM_OBJECT)       ",
        "(XMM_PAGER)        ",
        "(XMM_KERNEL)       ",
        "(XMM_REPLY)        ",
        "(NOTDEF 15)        ",
        "(NOTDEF 16)        ",
        "(HOST_SECURITY)    ",
        "(LEDGER)           ",
        "(MASTER_DEVICE)    ",
        "(ACTIVATION)       ",  /* 20 */
        "(SUBSYSTEM)        ",
        "(IO_DONE_QUEUE)    ",
        "(SEMAPHORE)        ",
        "(LOCK_SET)         ",
        "(CLOCK)            ",
        "(CLOCK_CTRL)       ",  /* 26 */
        "(IOKIT_SPARE)      ",  /* 27 */
        "(NAMED_MEM_ENTRY)  ",  /* 28 */
        "(IOKIT_CONNECT)    ",
        "(IOKIT_OBJECT)     ",  /* 30 */
        "(UPL)              ",
                                                /* << new entries here  */
        "(UNKNOWN)          "   /* magic catchall       */
};
/* Please keep in sync with kern/ipc_kobject.h  */

void
ipc_object_print(
        ipc_object_t    object)
{
        int kotype;

        iprintf("%s", io_active(object) ? "active" : "dead");
        printf(", refs=%d", object->io_references);
        printf(", otype=%d", io_otype(object));
        kotype = io_kotype(object);
        if (kotype >= 0 && kotype < IKOT_MAX_TYPE)
                printf(", kotype=%d %s\n", io_kotype(object),
                       ikot_print_array[kotype]);
        else
                printf(", kotype=0x%x %s\n", io_kotype(object),
                       ikot_print_array[IKOT_UNKNOWN]);
}

#endif  /* MACH_KDB */