xnu-792.6.76.tar.gz

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

/*
 * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This 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,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * @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_kmsg.c
 *      Author: Rich Draves
 *      Date:   1989
 *
 *      Operations on kernel messages.
 */

#include <norma_vm.h>

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

#include <kern/kern_types.h>
#include <kern/assert.h>
#include <kern/ipc_kobject.h>
#include <kern/kalloc.h>
#include <kern/zalloc.h>
#include <kern/processor.h>
#include <kern/thread.h>
#include <kern/sched_prim.h>
#include <kern/spl.h>
#include <kern/misc_protos.h>
#include <kern/counters.h>
#include <kern/cpu_data.h>

#include <vm/vm_map.h>
#include <vm/vm_object.h>
#include <vm/vm_kern.h>

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

#include <string.h>

#ifdef ppc
#include <ppc/Firmware.h>
#include <ppc/low_trace.h>
#endif


extern vm_map_t         ipc_kernel_copy_map;
extern vm_size_t        ipc_kmsg_max_vm_space;
extern vm_size_t        msg_ool_size_small;

#define MSG_OOL_SIZE_SMALL      msg_ool_size_small

#if defined(__LP64__)
#define MAP_SIZE_DIFFERS(map)   (map->max_offset < MACH_VM_MAX_ADDRESS)
#define OTHER_OOL_DESCRIPTOR    mach_msg_ool_descriptor32_t
#define OTHER_OOL_PORTS_DESCRIPTOR      mach_msg_ool_ports_descriptor32_t
#else
#define MAP_SIZE_DIFFERS(map)   (map->max_offset > VM_MAX_ADDRESS)
#define OTHER_OOL_DESCRIPTOR    mach_msg_ool_descriptor64_t
#define OTHER_OOL_PORTS_DESCRIPTOR      mach_msg_ool_ports_descriptor64_t
#endif

#define DESC_SIZE_ADJUSTMENT    (sizeof(OTHER_OOL_DESCRIPTOR) - \
                                 sizeof(mach_msg_ool_descriptor_t))

/* scatter list macros */

#define SKIP_PORT_DESCRIPTORS(s, c)                                     \
MACRO_BEGIN                                                             \
        if ((s) != MACH_MSG_DESCRIPTOR_NULL) {                          \
                while ((c) > 0) {                                       \
                        if ((s)->type.type != MACH_MSG_PORT_DESCRIPTOR) \
                                break;                                  \
                        (s)++; (c)--;                                   \
                }                                                       \
                if (c == 0)                                             \
                        (s) = MACH_MSG_DESCRIPTOR_NULL;                 \
        }                                                               \
MACRO_END

#define INCREMENT_SCATTER(s, c, d)                                      \
MACRO_BEGIN                                                             \
        if ((s) != MACH_MSG_DESCRIPTOR_NULL) {                          \
            s = (d) ? (mach_msg_descriptor_t *)                         \
                ((OTHER_OOL_DESCRIPTOR *)(s) + 1) :                     \
                (s + 1);                                                \
                (c)--;                                                  \
        }                                                               \
MACRO_END

/* zone for cached ipc_kmsg_t structures */
zone_t                  ipc_kmsg_zone;

/*
 * Forward declarations
 */

void ipc_kmsg_clean(
        ipc_kmsg_t      kmsg);

void ipc_kmsg_clean_body(
        ipc_kmsg_t      kmsg,
        mach_msg_type_number_t  number,
        mach_msg_descriptor_t   *desc);

void ipc_kmsg_clean_partial(
        ipc_kmsg_t              kmsg,
        mach_msg_type_number_t  number,
        mach_msg_descriptor_t   *desc,
        vm_offset_t             paddr,
        vm_size_t               length);

mach_msg_return_t ipc_kmsg_copyin_body(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        vm_map_t                map);

/*
 *      We keep a per-processor cache of kernel message buffers.
 *      The cache saves the overhead/locking of using kalloc/kfree.
 *      The per-processor cache seems to miss less than a per-thread cache,
 *      and it also uses less memory.  Access to the cache doesn't
 *      require locking.
 */

/*
 *      Routine:        ipc_kmsg_alloc
 *      Purpose:
 *              Allocate a kernel message structure.  If we can get one from
 *              the cache, that is best.  Otherwise, allocate a new one.
 *      Conditions:
 *              Nothing locked.
 */
ipc_kmsg_t
ipc_kmsg_alloc(
        mach_msg_size_t msg_and_trailer_size)
{
        mach_msg_size_t max_expanded_size;
        ipc_kmsg_t kmsg;

#if !defined(__LP64__)
        mach_msg_size_t size = msg_and_trailer_size - MAX_TRAILER_SIZE;

        /*
         * LP64support -
         * Pad the allocation in case we need to expand the
         * message descrptors for user spaces with pointers larger than
         * the kernel's own.  We don't know how many descriptors
         * there are yet, so just assume the whole body could be
         * descriptors (if there could be any at all).
         *
         * The expansion space is left in front of the header,
         * because it is easier to pull the header and descriptors
         * forward as we process them than it is to push all the
         * data backwards.
         */
        max_expanded_size = 
                (size > sizeof(mach_msg_base_t)) ?
                (msg_and_trailer_size + DESC_SIZE_ADJUSTMENT * 
                 ((size - sizeof(mach_msg_base_t)) /
                  (sizeof(mach_msg_ool_descriptor_t))))
                :
                (msg_and_trailer_size);
#else
        max_expanded_size = msg_and_trailer_size;
#endif

        /* round up for ikm_cache */
        if (max_expanded_size < IKM_SAVED_MSG_SIZE)
                max_expanded_size = IKM_SAVED_MSG_SIZE;

        if (max_expanded_size == IKM_SAVED_MSG_SIZE) {
                struct ikm_cache        *cache;
                unsigned int            i;

                disable_preemption();
                cache = &PROCESSOR_DATA(current_processor(), ikm_cache);
                if ((i = cache->avail) > 0) {
                        assert(i <= IKM_STASH);
                        kmsg = cache->entries[--i];
                        cache->avail = i;
                        ikm_check_init(kmsg, max_expanded_size);
                        enable_preemption();
                        kmsg->ikm_header = (mach_msg_header_t *)
                                           ((vm_offset_t)(kmsg + 1) +
                                            max_expanded_size -
                                            msg_and_trailer_size);
                        return (kmsg);
                }
                enable_preemption();
                kmsg = (ipc_kmsg_t)zalloc(ipc_kmsg_zone);
        } else {
                kmsg = (ipc_kmsg_t)kalloc(ikm_plus_overhead(max_expanded_size));
        }

        if (kmsg != IKM_NULL) {
                ikm_init(kmsg, max_expanded_size);
                kmsg->ikm_header = (mach_msg_header_t *)
                                   ((vm_offset_t)(kmsg + 1) +
                                    max_expanded_size -
                                    msg_and_trailer_size);
        }
        return(kmsg);
}

/*
 *      Routine:        ipc_kmsg_free
 *      Purpose:
 *              Free a kernel message buffer.  If the kms is preallocated
 *              to a port, just "put it back (marked unused)."  We have to
 *              do this with the port locked.  The port may have its hold
 *              on our message released.  In that case, we have to just
 *              revert the message to a traditional one and free it normally.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_kmsg_free(
        ipc_kmsg_t      kmsg)
{
        mach_msg_size_t size = kmsg->ikm_size;
        ipc_port_t port;

        /*
         * Check to see if the message is bound to the port.  If so,
         * mark it not in use.  If the port isn't already dead, then
         * leave the message associated with it.  Otherwise, free it.
         */
        port = ikm_prealloc_inuse_port(kmsg);
        if (port != IP_NULL) {
                ip_lock(port);
                ikm_prealloc_clear_inuse(kmsg, port);
                if (ip_active(port) && (port->ip_premsg == kmsg)) {
                        assert(IP_PREALLOC(port));
                        ip_unlock(port);
                        return;
                }
                ip_check_unlock(port);  /* May be last reference */
        }

        /*
         * Peek and see if it has to go back in the cache.
         */
        if (kmsg->ikm_size == IKM_SAVED_MSG_SIZE) {
                struct ikm_cache        *cache;
                unsigned int            i;

                disable_preemption();
                cache = &PROCESSOR_DATA(current_processor(), ikm_cache);
                if ((i = cache->avail) < IKM_STASH) {
                        cache->entries[i] = kmsg;
                        cache->avail = i + 1;
                        enable_preemption();
                        return;
                }
                enable_preemption();
                zfree(ipc_kmsg_zone, kmsg);
                return;
        }
        kfree(kmsg, ikm_plus_overhead(size));
}


/*
 *      Routine:        ipc_kmsg_enqueue
 *      Purpose:
 *              Enqueue a kmsg.
 */

void
ipc_kmsg_enqueue(
        ipc_kmsg_queue_t        queue,
        ipc_kmsg_t              kmsg)
{
        ipc_kmsg_enqueue_macro(queue, kmsg);
}

/*
 *      Routine:        ipc_kmsg_dequeue
 *      Purpose:
 *              Dequeue and return a kmsg.
 */

ipc_kmsg_t
ipc_kmsg_dequeue(
        ipc_kmsg_queue_t        queue)
{
        ipc_kmsg_t first;

        first = ipc_kmsg_queue_first(queue);

        if (first != IKM_NULL)
                ipc_kmsg_rmqueue_first_macro(queue, first);

        return first;
}

/*
 *      Routine:        ipc_kmsg_rmqueue
 *      Purpose:
 *              Pull a kmsg out of a queue.
 */

void
ipc_kmsg_rmqueue(
        ipc_kmsg_queue_t        queue,
        ipc_kmsg_t              kmsg)
{
        ipc_kmsg_t next, prev;

        assert(queue->ikmq_base != IKM_NULL);

        next = kmsg->ikm_next;
        prev = kmsg->ikm_prev;

        if (next == kmsg) {
                assert(prev == kmsg);
                assert(queue->ikmq_base == kmsg);

                queue->ikmq_base = IKM_NULL;
        } else {
                if (queue->ikmq_base == kmsg)
                        queue->ikmq_base = next;

                next->ikm_prev = prev;
                prev->ikm_next = next;
        }
        /* XXX Temporary debug logic */
        assert(kmsg->ikm_next = IKM_BOGUS);
        assert(kmsg->ikm_prev = IKM_BOGUS);
}

/*
 *      Routine:        ipc_kmsg_queue_next
 *      Purpose:
 *              Return the kmsg following the given kmsg.
 *              (Or IKM_NULL if it is the last one in the queue.)
 */

ipc_kmsg_t
ipc_kmsg_queue_next(
        ipc_kmsg_queue_t        queue,
        ipc_kmsg_t              kmsg)
{
        ipc_kmsg_t next;

        assert(queue->ikmq_base != IKM_NULL);

        next = kmsg->ikm_next;
        if (queue->ikmq_base == next)
                next = IKM_NULL;

        return next;
}

/*
 *      Routine:        ipc_kmsg_destroy
 *      Purpose:
 *              Destroys a kernel message.  Releases all rights,
 *              references, and memory held by the message.
 *              Frees the message.
 *      Conditions:
 *              No locks held.
 */

void
ipc_kmsg_destroy(
        ipc_kmsg_t      kmsg)
{
        ipc_kmsg_queue_t queue;
        boolean_t empty;

        /*
         *      ipc_kmsg_clean can cause more messages to be destroyed.
         *      Curtail recursion by queueing messages.  If a message
         *      is already queued, then this is a recursive call.
         */

        queue = &(current_thread()->ith_messages);
        empty = ipc_kmsg_queue_empty(queue);
        ipc_kmsg_enqueue(queue, kmsg);

        if (empty) {
                /* must leave kmsg in queue while cleaning it */

                while ((kmsg = ipc_kmsg_queue_first(queue)) != IKM_NULL) {
                        ipc_kmsg_clean(kmsg);
                        ipc_kmsg_rmqueue(queue, kmsg);
                        ipc_kmsg_free(kmsg);
                }
        }
}

/*
 *      Routine:        ipc_kmsg_destroy_dest
 *      Purpose:
 *              Destroys a kernel message.  Releases all rights,
 *              references, and memory held by the message (including
 *              the destination port reference.
 *              Frees the message.
 *      Conditions:
 *              No locks held.
 */
void
ipc_kmsg_destroy_dest(
        ipc_kmsg_t kmsg)
{
    ipc_port_t port;
        
    port = kmsg->ikm_header->msgh_remote_port;

    ipc_port_release(port);
    kmsg->ikm_header->msgh_remote_port = MACH_PORT_NULL;
    ipc_kmsg_destroy(kmsg);
}

/*
 *      Routine:        ipc_kmsg_clean_body
 *      Purpose:
 *              Cleans the body of a kernel message.
 *              Releases all rights, references, and memory.
 *
 *      Conditions:
 *              No locks held.
 */

void
ipc_kmsg_clean_body(
        __unused ipc_kmsg_t     kmsg,
        mach_msg_type_number_t  number,
        mach_msg_descriptor_t   *saddr)
{
    mach_msg_descriptor_t       *eaddr;

    if ( number == 0 )
        return;

    eaddr = saddr + number;

    for ( ; saddr < eaddr; saddr++ ) {
        
        switch (saddr->type.type) {
            
            case MACH_MSG_PORT_DESCRIPTOR: {
                mach_msg_port_descriptor_t *dsc;

                dsc = &saddr->port;

                /* 
                 * Destroy port rights carried in the message 
                 */
                if (!IO_VALID((ipc_object_t) dsc->name))
                    continue;
                ipc_object_destroy((ipc_object_t) dsc->name, dsc->disposition);
                break;
            }
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR : {
                mach_msg_ool_descriptor_t *dsc;

                dsc = &saddr->out_of_line;
                
                /* 
                 * Destroy memory carried in the message 
                 */
                if (dsc->size == 0) {
                        assert(dsc->address == (void *) 0);
                } else {
                        vm_map_copy_discard((vm_map_copy_t) dsc->address);
                }
                break;
            }
            case MACH_MSG_OOL_PORTS_DESCRIPTOR : {
                ipc_object_t                    *objects;
                mach_msg_type_number_t          j;
                mach_msg_ool_ports_descriptor_t *dsc;

                dsc = &saddr->ool_ports;
                objects = (ipc_object_t *) dsc->address;

                if (dsc->count == 0) {
                        break;
                }

                assert(objects != (ipc_object_t *) 0);
                
                /* destroy port rights carried in the message */
                
                for (j = 0; j < dsc->count; j++) {
                    ipc_object_t object = objects[j];
                    
                    if (!IO_VALID(object))
                        continue;
                    
                    ipc_object_destroy(object, dsc->disposition);
                }

                /* destroy memory carried in the message */

                assert(dsc->count != 0);

                kfree(dsc->address, 
                     (vm_size_t) dsc->count * sizeof(mach_port_name_t));
                break;
            }
            default : {
                printf("cleanup: don't understand this type of descriptor\n");
            }
        }
    }
}

/*
 *      Routine:        ipc_kmsg_clean_partial
 *      Purpose:
 *              Cleans a partially-acquired kernel message.
 *              number is the index of the type descriptor
 *              in the body of the message that contained the error.
 *              If dolast, the memory and port rights in this last
 *              type spec are also cleaned.  In that case, number
 *              specifies the number of port rights to clean.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_kmsg_clean_partial(
        ipc_kmsg_t              kmsg,
        mach_msg_type_number_t  number,
        mach_msg_descriptor_t   *desc,
        vm_offset_t             paddr,
        vm_size_t               length)
{
        ipc_object_t object;
        mach_msg_bits_t mbits = kmsg->ikm_header->msgh_bits;

        object = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        assert(IO_VALID(object));
        ipc_object_destroy(object, MACH_MSGH_BITS_REMOTE(mbits));

        object = (ipc_object_t) kmsg->ikm_header->msgh_local_port;
        if (IO_VALID(object))
                ipc_object_destroy(object, MACH_MSGH_BITS_LOCAL(mbits));

        if (paddr) {
                (void) vm_deallocate(ipc_kernel_copy_map, paddr, length);
        }

        ipc_kmsg_clean_body(kmsg, number, desc);
}

/*
 *      Routine:        ipc_kmsg_clean
 *      Purpose:
 *              Cleans a kernel message.  Releases all rights,
 *              references, and memory held by the message.
 *      Conditions:
 *              No locks held.
 */

void
ipc_kmsg_clean(
        ipc_kmsg_t      kmsg)
{
        ipc_object_t object;
        mach_msg_bits_t mbits;

        mbits = kmsg->ikm_header->msgh_bits;
        object = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        if (IO_VALID(object))
                ipc_object_destroy(object, MACH_MSGH_BITS_REMOTE(mbits));

        object = (ipc_object_t) kmsg->ikm_header->msgh_local_port;
        if (IO_VALID(object))
                ipc_object_destroy(object, MACH_MSGH_BITS_LOCAL(mbits));

        if (mbits & MACH_MSGH_BITS_COMPLEX) {
                mach_msg_body_t *body;

                body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
                ipc_kmsg_clean_body(kmsg, body->msgh_descriptor_count,
                                    (mach_msg_descriptor_t *)(body + 1));
        }
}

/*
 *      Routine:        ipc_kmsg_set_prealloc
 *      Purpose:
 *              Assign a kmsg as a preallocated message buffer to a port.
 *      Conditions:
 *              port locked.
 */

void
ipc_kmsg_set_prealloc(
        ipc_kmsg_t              kmsg,
        ipc_port_t              port)
{
        assert(kmsg->ikm_prealloc == IP_NULL);
  
        kmsg->ikm_prealloc = IP_NULL;
        IP_SET_PREALLOC(port, kmsg);
}

/*
 *      Routine:        ipc_kmsg_clear_prealloc
 *      Purpose:
 *              Release the Assignment of a preallocated message buffer from a port.
 *      Conditions:
 *              port locked.
 */
void
ipc_kmsg_clear_prealloc(
        ipc_kmsg_t              kmsg,
        ipc_port_t              port)
{
        assert(kmsg->ikm_prealloc == port);
  
        kmsg->ikm_prealloc = IP_NULL;
        IP_CLEAR_PREALLOC(port, kmsg);
}



/*
 *      Routine:        ipc_kmsg_get
 *      Purpose:
 *              Allocates a kernel message buffer.
 *              Copies a user message to the message buffer.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Acquired a message buffer.
 *              MACH_SEND_MSG_TOO_SMALL Message smaller than a header.
 *              MACH_SEND_MSG_TOO_SMALL Message size not long-word multiple.
 *              MACH_SEND_NO_BUFFER     Couldn't allocate a message buffer.
 *              MACH_SEND_INVALID_DATA  Couldn't copy message data.
 */

mach_msg_return_t
ipc_kmsg_get(
        mach_vm_address_t       msg_addr,
        mach_msg_size_t size,
        ipc_kmsg_t              *kmsgp)
{
        mach_msg_size_t                 msg_and_trailer_size;
        ipc_kmsg_t                      kmsg;
        mach_msg_max_trailer_t          *trailer;

        if ((size < sizeof(mach_msg_header_t)) || (size & 3))
                return MACH_SEND_MSG_TOO_SMALL;

        msg_and_trailer_size = size + MAX_TRAILER_SIZE;

        kmsg = ipc_kmsg_alloc(msg_and_trailer_size);

        if (kmsg == IKM_NULL)
                return MACH_SEND_NO_BUFFER;

        if (copyinmsg(msg_addr, (char *) kmsg->ikm_header, size)) {
                ipc_kmsg_free(kmsg);
                return MACH_SEND_INVALID_DATA;
        }

        kmsg->ikm_header->msgh_size = size;

        /* 
         * I reserve for the trailer the largest space (MAX_TRAILER_SIZE)
         * However, the internal size field of the trailer (msgh_trailer_size)
         * is initialized to the minimum (sizeof(mach_msg_trailer_t)), to optimize
         * the cases where no implicit data is requested.
         */
        trailer = (mach_msg_max_trailer_t *) ((vm_offset_t)kmsg->ikm_header + size);
        trailer->msgh_sender = current_thread()->task->sec_token;
        trailer->msgh_audit = current_thread()->task->audit_token;
        trailer->msgh_trailer_type = MACH_MSG_TRAILER_FORMAT_0;
        trailer->msgh_trailer_size = MACH_MSG_TRAILER_MINIMUM_SIZE;
        
#ifdef ppc
        if(trcWork.traceMask) dbgTrace(0x1100, (unsigned int)kmsg->ikm_header->msgh_id, 
                (unsigned int)kmsg->ikm_header->msgh_remote_port, 
                (unsigned int)kmsg->ikm_header->msgh_local_port, 0); 
#endif
        *kmsgp = kmsg;
        return MACH_MSG_SUCCESS;
}

/*
 *      Routine:        ipc_kmsg_get_from_kernel
 *      Purpose:
 *              First checks for a preallocated message
 *              reserved for kernel clients.  If not found -
 *              allocates a new kernel message buffer.
 *              Copies a kernel message to the message buffer.
 *              Only resource errors are allowed.
 *      Conditions:
 *              Nothing locked.
 *              Ports in header are ipc_port_t.
 *      Returns:
 *              MACH_MSG_SUCCESS        Acquired a message buffer.
 *              MACH_SEND_NO_BUFFER     Couldn't allocate a message buffer.
 */

mach_msg_return_t
ipc_kmsg_get_from_kernel(
        mach_msg_header_t       *msg,
        mach_msg_size_t size,
        ipc_kmsg_t              *kmsgp)
{
        ipc_kmsg_t      kmsg;
        mach_msg_size_t msg_and_trailer_size;
        mach_msg_max_trailer_t *trailer;
        ipc_port_t      dest_port;

        assert(size >= sizeof(mach_msg_header_t));
//      assert((size & 3) == 0);

        assert(IP_VALID((ipc_port_t) msg->msgh_remote_port));
        dest_port = (ipc_port_t)msg->msgh_remote_port;

        msg_and_trailer_size = size + MAX_TRAILER_SIZE;

        /*
         * See if the port has a pre-allocated kmsg for kernel
         * clients.  These are set up for those kernel clients
         * which cannot afford to wait.
         */
        if (IP_PREALLOC(dest_port)) {
                ip_lock(dest_port);
                if (!ip_active(dest_port)) {
                        ip_unlock(dest_port);
                        return MACH_SEND_NO_BUFFER;
                }
                assert(IP_PREALLOC(dest_port));
                kmsg = dest_port->ip_premsg;
                if (msg_and_trailer_size > kmsg->ikm_size) {
                        ip_unlock(dest_port);
                        return MACH_SEND_TOO_LARGE;
                }
                if (ikm_prealloc_inuse(kmsg)) {
                        ip_unlock(dest_port);
                        return MACH_SEND_NO_BUFFER;
                }
                ikm_prealloc_set_inuse(kmsg, dest_port);
                ip_unlock(dest_port);
        } else {
                kmsg = ipc_kmsg_alloc(msg_and_trailer_size);
                if (kmsg == IKM_NULL)
                        return MACH_SEND_NO_BUFFER;
        }

        (void) memcpy((void *) kmsg->ikm_header, (const void *) msg, size);

        kmsg->ikm_header->msgh_size = size;

        /* 
         * I reserve for the trailer the largest space (MAX_TRAILER_SIZE)
         * However, the internal size field of the trailer (msgh_trailer_size)
         * is initialized to the minimum (sizeof(mach_msg_trailer_t)), to
         * optimize the cases where no implicit data is requested.
         */
        trailer = (mach_msg_max_trailer_t *) 
                  ((vm_offset_t)kmsg->ikm_header + size);
        trailer->msgh_sender = KERNEL_SECURITY_TOKEN;
        trailer->msgh_audit = KERNEL_AUDIT_TOKEN;
        trailer->msgh_trailer_type = MACH_MSG_TRAILER_FORMAT_0;
        trailer->msgh_trailer_size = MACH_MSG_TRAILER_MINIMUM_SIZE;

        *kmsgp = kmsg;
        return MACH_MSG_SUCCESS;
}

/*
 *      Routine:        ipc_kmsg_send
 *      Purpose:
 *              Send a message.  The message holds a reference
 *              for the destination port in the msgh_remote_port field.
 *
 *              If unsuccessful, the caller still has possession of
 *              the message and must do something with it.  If successful,
 *              the message is queued, given to a receiver, destroyed,
 *              or handled directly by the kernel via mach_msg.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        The message was accepted.
 *              MACH_SEND_TIMED_OUT     Caller still has message.
 *              MACH_SEND_INTERRUPTED   Caller still has message.
 */
mach_msg_return_t
ipc_kmsg_send(
        ipc_kmsg_t              kmsg,
        mach_msg_option_t       option,
        mach_msg_timeout_t      send_timeout)
{
        ipc_port_t port;

        port = (ipc_port_t) kmsg->ikm_header->msgh_remote_port;
        assert(IP_VALID(port));

        ip_lock(port);

        if (port->ip_receiver == ipc_space_kernel) {

                /*
                 *      We can check ip_receiver == ipc_space_kernel
                 *      before checking that the port is active because
                 *      ipc_port_dealloc_kernel clears ip_receiver
                 *      before destroying a kernel port.
                 */
                assert(ip_active(port));
                port->ip_messages.imq_seqno++;
                ip_unlock(port);

                current_task()->messages_sent++;

                /*
                 * Call the server routine, and get the reply message to send.
                 */
                kmsg = ipc_kobject_server(kmsg);
                if (kmsg == IKM_NULL)
                        return MACH_MSG_SUCCESS;

                port = (ipc_port_t) kmsg->ikm_header->msgh_remote_port;
                assert(IP_VALID(port));
                ip_lock(port);
                /* fall thru with reply - same options */
        }

        /*
         *      Can't deliver to a dead port.
         *      However, we can pretend it got sent
         *      and was then immediately destroyed.
         */
        if (!ip_active(port)) {
                /*
                 *      We can't let ipc_kmsg_destroy deallocate
                 *      the port right, because we might end up
                 *      in an infinite loop trying to deliver
                 *      a send-once notification.
                 */

                ip_release(port);
                ip_check_unlock(port);
                kmsg->ikm_header->msgh_remote_port = MACH_PORT_NULL;
                ipc_kmsg_destroy(kmsg);
                return MACH_MSG_SUCCESS;
        }

        if (kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_CIRCULAR) {
                ip_unlock(port);

                /* don't allow the creation of a circular loop */

                ipc_kmsg_destroy(kmsg);
                return MACH_MSG_SUCCESS;
        }

        /*
         * We have a valid message and a valid reference on the port.
         * we can unlock the port and call mqueue_send() on it's message
         * queue.
         */
        ip_unlock(port);
        return (ipc_mqueue_send(&port->ip_messages, kmsg, option, send_timeout));
}

/*
 *      Routine:        ipc_kmsg_put
 *      Purpose:
 *              Copies a message buffer to a user message.
 *              Copies only the specified number of bytes.
 *              Frees the message buffer.
 *      Conditions:
 *              Nothing locked.  The message buffer must have clean
 *              header fields.
 *      Returns:
 *              MACH_MSG_SUCCESS        Copied data out of message buffer.
 *              MACH_RCV_INVALID_DATA   Couldn't copy to user message.
 */

mach_msg_return_t
ipc_kmsg_put(
        mach_vm_address_t       msg_addr,
        ipc_kmsg_t              kmsg,
        mach_msg_size_t         size)
{
        mach_msg_return_t mr;

        if (copyoutmsg((const char *) kmsg->ikm_header, msg_addr, size))
                mr = MACH_RCV_INVALID_DATA;
        else
                mr = MACH_MSG_SUCCESS;

        ipc_kmsg_free(kmsg);
        return mr;
}

/*
 *      Routine:        ipc_kmsg_put_to_kernel
 *      Purpose:
 *              Copies a message buffer to a kernel message.
 *              Frees the message buffer.
 *              No errors allowed.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_kmsg_put_to_kernel(
        mach_msg_header_t       *msg,
        ipc_kmsg_t              kmsg,
        mach_msg_size_t         size)
{
        (void) memcpy((void *) msg, (const void *) kmsg->ikm_header, size);

        ipc_kmsg_free(kmsg);
}

/*
 *      Routine:        ipc_kmsg_copyin_header
 *      Purpose:
 *              "Copy-in" port rights in the header of a message.
 *              Operates atomically; if it doesn't succeed the
 *              message header and the space are left untouched.
 *              If it does succeed the remote/local port fields
 *              contain object pointers instead of port names,
 *              and the bits field is updated.  The destination port
 *              will be a valid port pointer.
 *
 *              The notify argument implements the MACH_SEND_CANCEL option.
 *              If it is not MACH_PORT_NULL, it should name a receive right.
 *              If the processing of the destination port would generate
 *              a port-deleted notification (because the right for the
 *              destination port is destroyed and it had a request for
 *              a dead-name notification registered), and the port-deleted
 *              notification would be sent to the named receive right,
 *              then it isn't sent and the send-once right for the notify
 *              port is quietly destroyed.
 *
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Successful copyin.
 *              MACH_SEND_INVALID_HEADER
 *                      Illegal value in the message header bits.
 *              MACH_SEND_INVALID_DEST  The space is dead.
 *              MACH_SEND_INVALID_NOTIFY
 *                      Notify is non-null and doesn't name a receive right.
 *                      (Either KERN_INVALID_NAME or KERN_INVALID_RIGHT.)
 *              MACH_SEND_INVALID_DEST  Can't copyin destination port.
 *                      (Either KERN_INVALID_NAME or KERN_INVALID_RIGHT.)
 *              MACH_SEND_INVALID_REPLY Can't copyin reply port.
 *                      (Either KERN_INVALID_NAME or KERN_INVALID_RIGHT.)
 */

mach_msg_return_t
ipc_kmsg_copyin_header(
        mach_msg_header_t       *msg,
        ipc_space_t             space,
        mach_port_name_t        notify)
{
        mach_msg_bits_t mbits = msg->msgh_bits & MACH_MSGH_BITS_USER;
        mach_port_name_t dest_name = (mach_port_name_t)msg->msgh_remote_port;
        mach_port_name_t reply_name = (mach_port_name_t)msg->msgh_local_port;
        kern_return_t kr;

        mach_msg_type_name_t dest_type = MACH_MSGH_BITS_REMOTE(mbits);
        mach_msg_type_name_t reply_type = MACH_MSGH_BITS_LOCAL(mbits);
        ipc_object_t dest_port, reply_port;
        ipc_port_t dest_soright, reply_soright;
        ipc_port_t notify_port;

        if ((mbits != msg->msgh_bits) ||
            (!MACH_MSG_TYPE_PORT_ANY_SEND(dest_type)) ||
            ((reply_type == 0) ?
             (reply_name != MACH_PORT_NULL) :
             !MACH_MSG_TYPE_PORT_ANY_SEND(reply_type)))
                return MACH_SEND_INVALID_HEADER;

        reply_soright = IP_NULL; /* in case we go to invalid dest early */

        is_write_lock(space);
        if (!space->is_active)
                goto invalid_dest;

        if (!MACH_PORT_VALID(dest_name))
                goto invalid_dest;

        if (notify != MACH_PORT_NULL) {
                ipc_entry_t entry;

                if ((entry = ipc_entry_lookup(space, notify)) == IE_NULL) {
                        is_write_unlock(space);
                        return MACH_SEND_INVALID_NOTIFY;
                }
                if((entry->ie_bits & MACH_PORT_TYPE_RECEIVE) == 0) {
                        is_write_unlock(space);
                        return MACH_SEND_INVALID_NOTIFY;
                }

                notify_port = (ipc_port_t) entry->ie_object;
        } else
                notify_port = IP_NULL;

        if (dest_name == reply_name) {
                ipc_entry_t entry;
                mach_port_name_t name = dest_name;

                /*
                 *      Destination and reply ports are the same!
                 *      This is a little tedious to make atomic, because
                 *      there are 25 combinations of dest_type/reply_type.
                 *      However, most are easy.  If either is move-sonce,
                 *      then there must be an error.  If either are
                 *      make-send or make-sonce, then we must be looking
                 *      at a receive right so the port can't die.
                 *      The hard cases are the combinations of
                 *      copy-send and make-send.
                 */

                entry = ipc_entry_lookup(space, name);
                if (entry == IE_NULL)
                        goto invalid_dest;

                assert(reply_type != 0); /* because name not null */

                if (!ipc_right_copyin_check(space, name, entry, reply_type))
                        goto invalid_reply;

                if ((dest_type == MACH_MSG_TYPE_MOVE_SEND_ONCE) ||
                    (reply_type == MACH_MSG_TYPE_MOVE_SEND_ONCE)) {
                        /*
                         *      Why must there be an error?  To get a valid
                         *      destination, this entry must name a live
                         *      port (not a dead name or dead port).  However
                         *      a successful move-sonce will destroy a
                         *      live entry.  Therefore the other copyin,
                         *      whatever it is, would fail.  We've already
                         *      checked for reply port errors above,
                         *      so report a destination error.
                         */

                        goto invalid_dest;
                } else if ((dest_type == MACH_MSG_TYPE_MAKE_SEND) ||
                           (dest_type == MACH_MSG_TYPE_MAKE_SEND_ONCE) ||
                           (reply_type == MACH_MSG_TYPE_MAKE_SEND) ||
                           (reply_type == MACH_MSG_TYPE_MAKE_SEND_ONCE)) {
                        kr = ipc_right_copyin(space, name, entry,
                                              dest_type, FALSE,
                                              &dest_port, &dest_soright);
                        if (kr != KERN_SUCCESS)
                                goto invalid_dest;

                        /*
                         *      Either dest or reply needs a receive right.
                         *      We know the receive right is there, because
                         *      of the copyin_check and copyin calls.  Hence
                         *      the port is not in danger of dying.  If dest
                         *      used the receive right, then the right needed
                         *      by reply (and verified by copyin_check) will
                         *      still be there.
                         */

                        assert(IO_VALID(dest_port));
                        assert(entry->ie_bits & MACH_PORT_TYPE_RECEIVE);
                        assert(dest_soright == IP_NULL);

                        kr = ipc_right_copyin(space, name, entry,
                                              reply_type, TRUE,
                                              &reply_port, &reply_soright);

                        assert(kr == KERN_SUCCESS);
                        assert(reply_port == dest_port);
                        assert(entry->ie_bits & MACH_PORT_TYPE_RECEIVE);
                        assert(reply_soright == IP_NULL);
                } else if ((dest_type == MACH_MSG_TYPE_COPY_SEND) &&
                           (reply_type == MACH_MSG_TYPE_COPY_SEND)) {
                        /*
                         *      To make this atomic, just do one copy-send,
                         *      and dup the send right we get out.
                         */

                        kr = ipc_right_copyin(space, name, entry,
                                              dest_type, FALSE,
                                              &dest_port, &dest_soright);
                        if (kr != KERN_SUCCESS)
                                goto invalid_dest;

                        assert(entry->ie_bits & MACH_PORT_TYPE_SEND);
                        assert(dest_soright == IP_NULL);

                        /*
                         *      It's OK if the port we got is dead now,
                         *      so reply_port is IP_DEAD, because the msg
                         *      won't go anywhere anyway.
                         */

                        reply_port = (ipc_object_t)
                                ipc_port_copy_send((ipc_port_t) dest_port);
                        reply_soright = IP_NULL;
                } else if ((dest_type == MACH_MSG_TYPE_MOVE_SEND) &&
                           (reply_type == MACH_MSG_TYPE_MOVE_SEND)) {
                        /*
                         *      This is an easy case.  Just use our
                         *      handy-dandy special-purpose copyin call
                         *      to get two send rights for the price of one.
                         */

                        kr = ipc_right_copyin_two(space, name, entry,
                                                  &dest_port, &dest_soright);
                        if (kr != KERN_SUCCESS)
                                goto invalid_dest;

                        /* the entry might need to be deallocated */
                        if (IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE)
                                ipc_entry_dealloc(space, name, entry);

                        reply_port = dest_port;
                        reply_soright = IP_NULL;
                } else {
                        ipc_port_t soright;

                        assert(((dest_type == MACH_MSG_TYPE_COPY_SEND) &&
                                (reply_type == MACH_MSG_TYPE_MOVE_SEND)) ||
                               ((dest_type == MACH_MSG_TYPE_MOVE_SEND) &&
                                (reply_type == MACH_MSG_TYPE_COPY_SEND)));

                        /*
                         *      To make this atomic, just do a move-send,
                         *      and dup the send right we get out.
                         */

                        kr = ipc_right_copyin(space, name, entry,
                                              MACH_MSG_TYPE_MOVE_SEND, FALSE,
                                              &dest_port, &soright);
                        if (kr != KERN_SUCCESS)
                                goto invalid_dest;

                        /* the entry might need to be deallocated */

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

                        /*
                         *      It's OK if the port we got is dead now,
                         *      so reply_port is IP_DEAD, because the msg
                         *      won't go anywhere anyway.
                         */

                        reply_port = (ipc_object_t)
                                ipc_port_copy_send((ipc_port_t) dest_port);

                        if (dest_type == MACH_MSG_TYPE_MOVE_SEND) {
                                dest_soright = soright;
                                reply_soright = IP_NULL;
                        } else {
                                dest_soright = IP_NULL;
                                reply_soright = soright;
                        }
                }
        } else if (!MACH_PORT_VALID(reply_name)) {
                ipc_entry_t entry;

                /*
                 *      No reply port!  This is an easy case
                 *      to make atomic.  Just copyin the destination.
                 */

                entry = ipc_entry_lookup(space, dest_name);
                if (entry == IE_NULL)
                        goto invalid_dest;

                kr = ipc_right_copyin(space, dest_name, entry,
                                      dest_type, FALSE,
                                      &dest_port, &dest_soright);
                if (kr != KERN_SUCCESS)
                        goto invalid_dest;

                /* the entry might need to be deallocated */

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

                reply_port = (ipc_object_t) reply_name;
                reply_soright = IP_NULL;
        } else {
                ipc_entry_t dest_entry, reply_entry;

                /*
                 *      This is the tough case to make atomic.
                 *      The difficult problem is serializing with port death.
                 *      At the time we copyin dest_port, it must be alive.
                 *      If reply_port is alive when we copyin it, then
                 *      we are OK, because we serialize before the death
                 *      of both ports.  Assume reply_port is dead at copyin.
                 *      Then if dest_port dies/died after reply_port died,
                 *      we are OK, because we serialize between the death
                 *      of the two ports.  So the bad case is when dest_port
                 *      dies after its copyin, reply_port dies before its
                 *      copyin, and dest_port dies before reply_port.  Then
                 *      the copyins operated as if dest_port was alive
                 *      and reply_port was dead, which shouldn't have happened
                 *      because they died in the other order.
                 *
                 *      Note that it is easy for a user task to tell if
                 *      a copyin happened before or after a port died.
                 *      For example, suppose both dest and reply are
                 *      send-once rights (types are both move-sonce) and
                 *      both rights have dead-name requests registered.
                 *      If a port dies before copyin, a dead-name notification
                 *      is generated and the dead name's urefs are incremented,
                 *      and if the copyin happens first, a port-deleted
                 *      notification is generated.
                 *
                 *      Note that although the entries are different,
                 *      dest_port and reply_port might still be the same.
                 *
                 * JMM - The code to handle this was too expensive and, anyway,
                 * we intend to separate the dest lookup from the reply copyin
                 * by a wide margin, so the user will have to learn to deal!
                 * I will be making the change soon!
                 */

                dest_entry = ipc_entry_lookup(space, dest_name);
                if (dest_entry == IE_NULL)
                        goto invalid_dest;

                reply_entry = ipc_entry_lookup(space, reply_name);
                if (reply_entry == IE_NULL)
                        goto invalid_reply;

                assert(dest_entry != reply_entry); /* names are not equal */
                assert(reply_type != 0); /* because reply_name not null */

                if (!ipc_right_copyin_check(space, reply_name, reply_entry,
                                            reply_type))
                        goto invalid_reply;

                kr = ipc_right_copyin(space, dest_name, dest_entry,
                                      dest_type, FALSE,
                                      &dest_port, &dest_soright);
                if (kr != KERN_SUCCESS)
                        goto invalid_dest;

                assert(IO_VALID(dest_port));

                kr = ipc_right_copyin(space, reply_name, reply_entry,
                                      reply_type, TRUE,
                                      &reply_port, &reply_soright);

                assert(kr == KERN_SUCCESS);

                /* the entries might need to be deallocated */

                if (IE_BITS_TYPE(reply_entry->ie_bits) == MACH_PORT_TYPE_NONE)
                        ipc_entry_dealloc(space, reply_name, reply_entry);

                if (IE_BITS_TYPE(dest_entry->ie_bits) == MACH_PORT_TYPE_NONE)
                        ipc_entry_dealloc(space, dest_name, dest_entry);
        }

        /*
         *      At this point, dest_port, reply_port,
         *      dest_soright, reply_soright are all initialized.
         *      Any defunct entries have been deallocated.
         *      The space is still write-locked, and we need to
         *      make the MACH_SEND_CANCEL check.  The notify_port pointer
         *      is still usable, because the copyin code above won't ever
         *      deallocate a receive right, so its entry still exists
         *      and holds a ref.  Note notify_port might even equal
         *      dest_port or reply_port.
         */

        if ((notify != MACH_PORT_NULL) &&
            (dest_soright == notify_port)) {
                ipc_port_release_sonce(dest_soright);
                dest_soright = IP_NULL;
        }

        is_write_unlock(space);

        if (dest_soright != IP_NULL)
                ipc_notify_port_deleted(dest_soright, dest_name);

        if (reply_soright != IP_NULL)
                ipc_notify_port_deleted(reply_soright, reply_name);

        dest_type = ipc_object_copyin_type(dest_type);
        reply_type = ipc_object_copyin_type(reply_type);

        msg->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
                          MACH_MSGH_BITS(dest_type, reply_type));
        msg->msgh_remote_port = (ipc_port_t)dest_port;
        msg->msgh_local_port = (ipc_port_t)reply_port;

        return MACH_MSG_SUCCESS;

invalid_reply:
        is_write_unlock(space);
        return MACH_SEND_INVALID_REPLY;

invalid_dest:
        is_write_unlock(space);
        if (reply_soright != IP_NULL)
                ipc_notify_port_deleted(reply_soright, reply_name);
        return MACH_SEND_INVALID_DEST;
}

/*
 *      Routine:        ipc_kmsg_copyin_body
 *      Purpose:
 *              "Copy-in" port rights and out-of-line memory
 *              in the message body.
 *
 *              In all failure cases, the message is left holding
 *              no rights or memory.  However, the message buffer
 *              is not deallocated.  If successful, the message
 *              contains a valid destination port.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Successful copyin.
 *              MACH_SEND_INVALID_MEMORY        Can't grab out-of-line memory.
 *              MACH_SEND_INVALID_RIGHT Can't copyin port right in body.
 *              MACH_SEND_INVALID_TYPE  Bad type specification.
 *              MACH_SEND_MSG_TOO_SMALL Body is too small for types/data.
 *              MACH_SEND_INVALID_RT_OOL_SIZE OOL Buffer too large for RT
 *              MACH_MSG_INVALID_RT_DESCRIPTOR Dealloc and RT are incompatible
 */

#define DESC_COUNT_SMALL 64

mach_msg_return_t
ipc_kmsg_copyin_body(
        ipc_kmsg_t      kmsg,
        ipc_space_t     space,
        vm_map_t        map)
{
    ipc_object_t                dest;
    mach_msg_body_t             *body;
    mach_msg_descriptor_t       *daddr, *naddr;
    mach_msg_type_number_t      dsc_count;
    boolean_t                   differs = MAP_SIZE_DIFFERS(map);
    boolean_t                   complex = FALSE;
    vm_size_t                   space_needed = 0;
    vm_size_t                   desc_size_space[DESC_COUNT_SMALL];
    vm_size_t                   *user_desc_sizes = NULL;
    vm_offset_t                 paddr = 0;
    vm_map_copy_t               copy = VM_MAP_COPY_NULL;
    kern_return_t               kr;
    mach_msg_type_number_t      i;
    mach_msg_return_t           mr = MACH_MSG_SUCCESS;
    
    /*
     * Determine if the target is a kernel port.
     */
    dest = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
    body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
    naddr = (mach_msg_descriptor_t *) (body + 1);

    dsc_count = body->msgh_descriptor_count;
    if (dsc_count == 0)
        return MACH_MSG_SUCCESS;

    if (differs) {
        user_desc_sizes = (dsc_count <= DESC_COUNT_SMALL) ?
            &desc_size_space : kalloc(dsc_count * sizeof(vm_size_t));
        if (user_desc_sizes == NULL) {
            ipc_kmsg_clean_partial(kmsg,0,0,0,0);
            return KERN_RESOURCE_SHORTAGE;
        }
    }

    /*
     * Make an initial pass to determine kernal VM space requirements for
     * physical copies and possible contraction of the descriptors from
     * processes with pointers larger than the kernel's.
     */
    daddr = 0;
    for (i = 0; i < dsc_count; i++) {
        daddr = naddr;

        /* make sure the descriptor fits in the message */
        if (differs) {
            switch (daddr->type.type) {
            case MACH_MSG_OOL_DESCRIPTOR:
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_PORTS_DESCRIPTOR:
                user_desc_sizes[i] = sizeof(OTHER_OOL_DESCRIPTOR);
                break;
            default:
                user_desc_sizes[i] = sizeof(*daddr);
                break;
            }
            naddr = (mach_msg_descriptor_t *)
                    ((vm_offset_t)daddr + user_desc_sizes[i]);
        } else {
            naddr = daddr + 1;
        }

        if (naddr > (mach_msg_descriptor_t *)
            ((vm_offset_t)kmsg->ikm_header + kmsg->ikm_header->msgh_size)) {
            ipc_kmsg_clean_partial(kmsg,0,0,0,0);
            mr = MACH_SEND_MSG_TOO_SMALL;
            goto out;
        }

        switch (daddr->type.type) {
            mach_msg_size_t size;

        case MACH_MSG_OOL_DESCRIPTOR:
        case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            size = (differs) ?
                ((OTHER_OOL_DESCRIPTOR *)daddr)->size :
            daddr->out_of_line.size;

            if (daddr->out_of_line.copy != MACH_MSG_PHYSICAL_COPY &&
                daddr->out_of_line.copy != MACH_MSG_VIRTUAL_COPY) {
                /*
                 * Invalid copy option
                 */
                ipc_kmsg_clean_partial(kmsg,0,0,0,0);
                mr = MACH_SEND_INVALID_TYPE;
                goto out;
            }
            
            if ((size >= MSG_OOL_SIZE_SMALL) &&
                (daddr->out_of_line.copy == MACH_MSG_PHYSICAL_COPY) &&
                !(daddr->out_of_line.deallocate)) {

                /*
                 * Out-of-line memory descriptor, accumulate kernel
                 * memory requirements
                 */
                space_needed += round_page(size);
                if (space_needed > ipc_kmsg_max_vm_space) {
                    
                    /*
                     * Per message kernel memory limit exceeded
                     */
                    ipc_kmsg_clean_partial(kmsg,0,0,0,0);
                    mr = MACH_MSG_VM_KERNEL;
                    goto out;
                }
            }
        }
    }

    /*
     * Allocate space in the pageable kernel ipc copy map for all the
     * ool data that is to be physically copied.  Map is marked wait for
     * space.
     */
    if (space_needed) {
        if (vm_allocate(ipc_kernel_copy_map, &paddr, space_needed, VM_FLAGS_ANYWHERE) !=
            KERN_SUCCESS) {
            ipc_kmsg_clean_partial(kmsg,0,0,0,0);
                mr = MACH_MSG_VM_KERNEL;
                goto out;
        }
    }

    /* 
     * handle the OOL regions and port descriptors.
     * We process them in reverse order starting with the last one
     * scanned above.  That way, we can compact them up against
     * the message body (if the user-descriptor size is larger than
     * the kernel representation).
     */
    naddr -= 1;
    do {

        switch (daddr->type.type) {
            
            /* port descriptors are the same size everywhere, how nice */
            case MACH_MSG_PORT_DESCRIPTOR: {
                mach_msg_type_name_t            user_disp;
                mach_msg_type_name_t            result_disp;
                mach_port_name_t                name;
                ipc_object_t                    object;
                volatile mach_msg_port_descriptor_t     *dsc;
                volatile mach_msg_port_descriptor_t     *user_dsc;
                
                user_dsc = &daddr->port;
                dsc = &naddr->port;
                
                user_disp = user_dsc->disposition;
                result_disp = ipc_object_copyin_type(user_disp);
                
                name = (mach_port_name_t)user_dsc->name;
                if (MACH_PORT_VALID(name)) {

                    kr = ipc_object_copyin(space, name, user_disp, &object);
                    if (kr != KERN_SUCCESS) {
                        mr = MACH_SEND_INVALID_RIGHT;
                        break;
                    }

                    if ((result_disp == MACH_MSG_TYPE_PORT_RECEIVE) &&
                        ipc_port_check_circularity((ipc_port_t) object,
                                                   (ipc_port_t) dest)) {
                        kmsg->ikm_header->msgh_bits |= MACH_MSGH_BITS_CIRCULAR;
                    }
                    dsc->name = (ipc_port_t) object;
                } else {
                    dsc->name = (mach_port_t)name;
                }
                dsc->disposition = result_disp;
                dsc->type = MACH_MSG_PORT_DESCRIPTOR;
                complex = TRUE;
                break;
            }

            /* out of line descriptors differ in size between 32 and 64 bit processes */
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR: {
                vm_size_t                       length;
                boolean_t                       dealloc;
                mach_msg_copy_options_t         copy_options;
                mach_vm_offset_t                addr;
                mach_msg_descriptor_type_t      dsc_type;

                volatile mach_msg_ool_descriptor_t      *dsc;

                if (differs) {
                    volatile OTHER_OOL_DESCRIPTOR       *user_dsc;

                    user_dsc = (OTHER_OOL_DESCRIPTOR *)&daddr->out_of_line;
                    addr = (mach_vm_offset_t) user_dsc->address;
                    length = user_dsc->size;
                    dealloc = user_dsc->deallocate;
                    copy_options = user_dsc->copy;
                    dsc_type = user_dsc->type;
                } else {
                    volatile mach_msg_ool_descriptor_t  *user_dsc;
                
                    user_dsc = &daddr->out_of_line;
                    addr = CAST_USER_ADDR_T(user_dsc->address);
                    dealloc = user_dsc->deallocate;
                    copy_options = user_dsc->copy;
                    dsc_type = user_dsc->type;
                    length = user_dsc->size;
                }

                dsc = &naddr->out_of_line;
                dsc->size = length;
                dsc->deallocate = dealloc;
                dsc->copy = copy_options;
                dsc->type = dsc_type;

                if (length == 0) {
                    dsc->address = 0;
                } else if ((length >= MSG_OOL_SIZE_SMALL) &&
                           (copy_options == MACH_MSG_PHYSICAL_COPY) && !dealloc) {

                        /*
                         * If the request is a physical copy and the source
                         * is not being deallocated, then allocate space
                         * in the kernel's pageable ipc copy map and copy
                         * the data in.  The semantics guarantee that the
                         * data will have been physically copied before
                         * the send operation terminates.  Thus if the data
                         * is not being deallocated, we must be prepared
                         * to page if the region is sufficiently large.
                         */
                        if (copyin(addr, (char *) paddr, length)) {
                                mr = MACH_SEND_INVALID_MEMORY;
                                break;
                        }       

                        /*
                         * The kernel ipc copy map is marked no_zero_fill.
                         * If the transfer is not a page multiple, we need
                         * to zero fill the balance.
                         */
                        if (!page_aligned(length)) {
                                (void) memset((void *) (paddr + length), 0,
                                        round_page(length) - length);
                        }
                        if (vm_map_copyin(ipc_kernel_copy_map, (vm_map_address_t)paddr,
                                          (vm_map_size_t)length, TRUE, &copy) != KERN_SUCCESS) {
                            mr = MACH_MSG_VM_KERNEL;
                            break;
                        }
                        dsc->address = (void *) copy;
                        paddr += round_page(length);
                        space_needed -= round_page(length);
                } else {

                        /*
                         * Make a vm_map_copy_t of the of the data.  If the
                         * data is small, this will do an optimized physical
                         * copy.  Otherwise, it will do a virtual copy.
                         *
                         * NOTE: A virtual copy is OK if the original is being
                         * deallocted, even if a physical copy was requested.
                         */
                        kr = vm_map_copyin(map, addr, 
                                           (vm_map_size_t)length, dealloc, &copy);
                        if (kr != KERN_SUCCESS) {
                            mr = (kr == KERN_RESOURCE_SHORTAGE) ?
                                   MACH_MSG_VM_KERNEL :
                                   MACH_SEND_INVALID_MEMORY;
                            break;
                        }
                        dsc->address = (void *) copy;
                }
                complex = TRUE;
                break;
            }
            case MACH_MSG_OOL_PORTS_DESCRIPTOR: {
                vm_size_t                               length;
                void                                    *data;
                ipc_object_t                            *objects;
                unsigned int                            j;
                mach_vm_offset_t                        addr;
                mach_msg_type_name_t                    user_disp;
                mach_msg_type_name_t                    result_disp;
                mach_msg_type_number_t                  count;
                mach_msg_copy_options_t                 copy_option;
                boolean_t                               deallocate;

                volatile mach_msg_ool_ports_descriptor_t        *dsc;

                if (differs) {
                    volatile OTHER_OOL_PORTS_DESCRIPTOR         *user_dsc;
                    
                    user_dsc = (OTHER_OOL_PORTS_DESCRIPTOR *)&daddr->ool_ports;
                    addr = (mach_vm_offset_t)user_dsc->address;
                    count = user_dsc->count;
                    deallocate = user_dsc->deallocate;
                    copy_option = user_dsc->copy;
                    user_disp = user_dsc->disposition;
                } else {
                    volatile mach_msg_ool_ports_descriptor_t    *user_dsc;

                    user_dsc = &daddr->ool_ports;
                    addr = CAST_USER_ADDR_T(user_dsc->address);
                    count = user_dsc->count;
                    deallocate = user_dsc->deallocate;
                    copy_option = user_dsc->copy;
                    user_disp = user_dsc->disposition;
                }

                dsc = &naddr->ool_ports;
                dsc->deallocate = deallocate;
                dsc->copy = copy_option;
                dsc->type = daddr->type.type;
                dsc->count = count;

                /* calculate length of data in bytes, rounding up */
                length = count * sizeof(mach_port_name_t);
                
                if (length == 0) {
                    complex = TRUE;
                    dsc->address = (void *) 0;
                    break;
                }

                data = kalloc(length);

                if (data == NULL) {
                    mr = MACH_SEND_NO_BUFFER;
                    break;
                }
                
                if (copyinmap(map, addr, data, length) != KERN_SUCCESS) {
                    kfree(data, length);
                    mr = MACH_SEND_INVALID_MEMORY;
                    break;
                }

                if (deallocate) {
                    (void) mach_vm_deallocate(map, addr, (mach_vm_size_t)length);
                }
                
                dsc->address = data;
                
                result_disp = ipc_object_copyin_type(user_disp);
                dsc->disposition = result_disp;

                objects = (ipc_object_t *) data;
                
                for ( j = 0; j < count; j++) {
                    mach_port_name_t port = (mach_port_name_t) objects[j];
                    ipc_object_t object;
                    
                    if (!MACH_PORT_VALID(port))
                        continue;
                    
                    kr = ipc_object_copyin(space, port, user_disp, &object);

                    if (kr != KERN_SUCCESS) {
                        unsigned int k;

                        for(k = 0; k < j; k++) {
                            object = objects[k];
                            if (IPC_OBJECT_VALID(object))
                                ipc_object_destroy(object, result_disp);
                        }
                        kfree(data, length);
                        mr = MACH_SEND_INVALID_RIGHT;
                        break;
                    }
                    
                    if ((dsc->disposition == MACH_MSG_TYPE_PORT_RECEIVE) &&
                        ipc_port_check_circularity(
                                                   (ipc_port_t) object,
                                                   (ipc_port_t) dest))
                        kmsg->ikm_header->msgh_bits |= MACH_MSGH_BITS_CIRCULAR;
                    
                    objects[j] = object;
                }
                
                complex = TRUE;
                break;
            }
            default: {
                /*
                 * Invalid descriptor
                 */
                mr = MACH_SEND_INVALID_TYPE;
                break;
            }
        }

        if (MACH_MSG_SUCCESS != mr) {
            ipc_kmsg_clean_partial(kmsg, dsc_count - i,
                                   naddr + 1, paddr, space_needed);
            goto out;
        }

    } while (--i > 0
             && 
             (daddr = (differs) ? (mach_msg_descriptor_t *)((vm_offset_t)(daddr) -
                                  user_desc_sizes[i - 1]) : daddr - 1)
             &&
             naddr--);
    
    if (!complex) {
        kmsg->ikm_header->msgh_bits &= ~MACH_MSGH_BITS_COMPLEX;
    }

    if (differs && naddr != daddr) {
        mach_msg_base_t *old_base = (mach_msg_base_t *)kmsg->ikm_header;
        mach_msg_base_t *new_base = (mach_msg_base_t *)naddr - 1;

        memmove(new_base, old_base, sizeof(mach_msg_base_t));
        new_base->header.msgh_size -= (vm_offset_t)naddr - (vm_offset_t)daddr;
        kmsg->ikm_header = &new_base->header;
    }

 out:
    if (differs && dsc_count > DESC_COUNT_SMALL)
        kfree(user_desc_sizes, body->msgh_descriptor_count * sizeof(vm_size_t));

    return mr;
}


/*
 *      Routine:        ipc_kmsg_copyin
 *      Purpose:
 *              "Copy-in" port rights and out-of-line memory
 *              in the message.
 *
 *              In all failure cases, the message is left holding
 *              no rights or memory.  However, the message buffer
 *              is not deallocated.  If successful, the message
 *              contains a valid destination port.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Successful copyin.
 *              MACH_SEND_INVALID_HEADER
 *                      Illegal value in the message header bits.
 *              MACH_SEND_INVALID_NOTIFY        Bad notify port.
 *              MACH_SEND_INVALID_DEST  Can't copyin destination port.
 *              MACH_SEND_INVALID_REPLY Can't copyin reply port.
 *              MACH_SEND_INVALID_MEMORY        Can't grab out-of-line memory.
 *              MACH_SEND_INVALID_RIGHT Can't copyin port right in body.
 *              MACH_SEND_INVALID_TYPE  Bad type specification.
 *              MACH_SEND_MSG_TOO_SMALL Body is too small for types/data.
 */

mach_msg_return_t
ipc_kmsg_copyin(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        vm_map_t                map,
        mach_port_name_t        notify)
{
    mach_msg_return_t           mr;
    
    mr = ipc_kmsg_copyin_header(kmsg->ikm_header, space, notify);
    if (mr != MACH_MSG_SUCCESS)
        return mr;
    
    if ((kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_COMPLEX) == 0)
        return MACH_MSG_SUCCESS;
    
    return( ipc_kmsg_copyin_body( kmsg, space, map) );
}

/*
 *      Routine:        ipc_kmsg_copyin_from_kernel
 *      Purpose:
 *              "Copy-in" port rights and out-of-line memory
 *              in a message sent from the kernel.
 *
 *              Because the message comes from the kernel,
 *              the implementation assumes there are no errors
 *              or peculiarities in the message.
 *
 *              Returns TRUE if queueing the message
 *              would result in a circularity.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_kmsg_copyin_from_kernel(
        ipc_kmsg_t      kmsg)
{
        mach_msg_bits_t bits = kmsg->ikm_header->msgh_bits;
        mach_msg_type_name_t rname = MACH_MSGH_BITS_REMOTE(bits);
        mach_msg_type_name_t lname = MACH_MSGH_BITS_LOCAL(bits);
        ipc_object_t remote = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        ipc_object_t local = (ipc_object_t) kmsg->ikm_header->msgh_local_port;

        /* translate the destination and reply ports */

        ipc_object_copyin_from_kernel(remote, rname);
        if (IO_VALID(local))
                ipc_object_copyin_from_kernel(local, lname);

        /*
         *      The common case is a complex message with no reply port,
         *      because that is what the memory_object interface uses.
         */

        if (bits == (MACH_MSGH_BITS_COMPLEX |
                     MACH_MSGH_BITS(MACH_MSG_TYPE_COPY_SEND, 0))) {
                bits = (MACH_MSGH_BITS_COMPLEX |
                        MACH_MSGH_BITS(MACH_MSG_TYPE_PORT_SEND, 0));

                kmsg->ikm_header->msgh_bits = bits;
        } else {
                bits = (MACH_MSGH_BITS_OTHER(bits) |
                        MACH_MSGH_BITS(ipc_object_copyin_type(rname),
                                       ipc_object_copyin_type(lname)));

                kmsg->ikm_header->msgh_bits = bits;
                if ((bits & MACH_MSGH_BITS_COMPLEX) == 0)
                        return;
        }
    {
        mach_msg_descriptor_t   *saddr, *eaddr;
        mach_msg_body_t         *body;

        body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
        saddr = (mach_msg_descriptor_t *) (body + 1);
        eaddr = (mach_msg_descriptor_t *) saddr + body->msgh_descriptor_count;

        for ( ; saddr <  eaddr; saddr++) {

            switch (saddr->type.type) {
            
                case MACH_MSG_PORT_DESCRIPTOR: {
                    mach_msg_type_name_t        name;
                    ipc_object_t                object;
                    mach_msg_port_descriptor_t  *dsc;
                
                    dsc = &saddr->port;
                
                    /* this is really the type SEND, SEND_ONCE, etc. */
                    name = dsc->disposition;
                    object = (ipc_object_t) dsc->name;
                    dsc->disposition = ipc_object_copyin_type(name);
                
                    if (!IO_VALID(object)) {
                        break;
                    }

                    ipc_object_copyin_from_kernel(object, name);
                    
                    /* CDY avoid circularity when the destination is also */
                    /* the kernel.  This check should be changed into an  */
                    /* assert when the new kobject model is in place since*/
                    /* ports will not be used in kernel to kernel chats   */
                        
                    if (((ipc_port_t)remote)->ip_receiver != ipc_space_kernel) {
                       if ((dsc->disposition == MACH_MSG_TYPE_PORT_RECEIVE) &&
                           ipc_port_check_circularity((ipc_port_t) object, 
                                                (ipc_port_t) remote)) {
                           kmsg->ikm_header->msgh_bits |= 
                                        MACH_MSGH_BITS_CIRCULAR;
                       }
                    }
                    break;
                }
                case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
                case MACH_MSG_OOL_DESCRIPTOR: {
                    /*
                     * The sender should supply ready-made memory, i.e.
                     * a vm_map_copy_t, so we don't need to do anything.
                     */
                    break;
                }
                case MACH_MSG_OOL_PORTS_DESCRIPTOR: {
                    ipc_object_t                        *objects;
                    unsigned int                        j;
                    mach_msg_type_name_t                name;
                    mach_msg_ool_ports_descriptor_t     *dsc;
                
                    dsc = &saddr->ool_ports;

                    /* this is really the type SEND, SEND_ONCE, etc. */
                    name = dsc->disposition;
                    dsc->disposition = ipc_object_copyin_type(name);
                
                    objects = (ipc_object_t *) dsc->address;
                
                    for ( j = 0; j < dsc->count; j++) {
                        ipc_object_t object = objects[j];
                        
                        if (!IO_VALID(object))
                            continue;
                        
                        ipc_object_copyin_from_kernel(object, name);
    
                        if ((dsc->disposition == MACH_MSG_TYPE_PORT_RECEIVE) &&
                            ipc_port_check_circularity(
                                                       (ipc_port_t) object,
                                                       (ipc_port_t) remote))
                            kmsg->ikm_header->msgh_bits |= MACH_MSGH_BITS_CIRCULAR;
                    }
                    break;
                }
                default: {
#if     MACH_ASSERT
                    panic("ipc_kmsg_copyin_from_kernel:  bad descriptor");
#endif  /* MACH_ASSERT */
                }
            }
        }
    }
}

/*
 *      Routine:        ipc_kmsg_copyout_header
 *      Purpose:
 *              "Copy-out" port rights in the header of a message.
 *              Operates atomically; if it doesn't succeed the
 *              message header and the space are left untouched.
 *              If it does succeed the remote/local port fields
 *              contain port names instead of object pointers,
 *              and the bits field is updated.
 *
 *              The notify argument implements the MACH_RCV_NOTIFY option.
 *              If it is not MACH_PORT_NULL, it should name a receive right.
 *              If the process of receiving the reply port creates a
 *              new right in the receiving task, then the new right is
 *              automatically registered for a dead-name notification,
 *              with the notify port supplying the send-once right.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Copied out port rights.
 *              MACH_RCV_INVALID_NOTIFY 
 *                      Notify is non-null and doesn't name a receive right.
 *                      (Either KERN_INVALID_NAME or KERN_INVALID_RIGHT.)
 *              MACH_RCV_HEADER_ERROR|MACH_MSG_IPC_SPACE
 *                      The space is dead.
 *              MACH_RCV_HEADER_ERROR|MACH_MSG_IPC_SPACE
 *                      No room in space for another name.
 *              MACH_RCV_HEADER_ERROR|MACH_MSG_IPC_KERNEL
 *                      Couldn't allocate memory for the reply port.
 *              MACH_RCV_HEADER_ERROR|MACH_MSG_IPC_KERNEL
 *                      Couldn't allocate memory for the dead-name request.
 */

mach_msg_return_t
ipc_kmsg_copyout_header(
        mach_msg_header_t       *msg,
        ipc_space_t             space,
        mach_port_name_t        notify)
{
        mach_msg_bits_t mbits = msg->msgh_bits;
        ipc_port_t dest = (ipc_port_t) msg->msgh_remote_port;

        assert(IP_VALID(dest));

    {
        mach_msg_type_name_t dest_type = MACH_MSGH_BITS_REMOTE(mbits);
        mach_msg_type_name_t reply_type = MACH_MSGH_BITS_LOCAL(mbits);
        ipc_port_t reply = (ipc_port_t) msg->msgh_local_port;
        mach_port_name_t dest_name, reply_name;

        if (IP_VALID(reply)) {
                ipc_port_t notify_port;
                ipc_entry_t entry;
                kern_return_t kr;

                /*
                 *      Handling notify (for MACH_RCV_NOTIFY) is tricky.
                 *      The problem is atomically making a send-once right
                 *      from the notify port and installing it for a
                 *      dead-name request in the new entry, because this
                 *      requires two port locks (on the notify port and
                 *      the reply port).  However, we can safely make
                 *      and consume send-once rights for the notify port
                 *      as long as we hold the space locked.  This isn't
                 *      an atomicity problem, because the only way
                 *      to detect that a send-once right has been created
                 *      and then consumed if it wasn't needed is by getting
                 *      at the receive right to look at ip_sorights, and
                 *      because the space is write-locked status calls can't
                 *      lookup the notify port receive right.  When we make
                 *      the send-once right, we lock the notify port,
                 *      so any status calls in progress will be done.
                 */

                is_write_lock(space);

                for (;;) {
                        ipc_port_request_index_t request;

                        if (!space->is_active) {
                                is_write_unlock(space);
                                return (MACH_RCV_HEADER_ERROR|
                                        MACH_MSG_IPC_SPACE);
                        }

                        if (notify != MACH_PORT_NULL) {
                                notify_port = ipc_port_lookup_notify(space,
                                                                     notify);
                                if (notify_port == IP_NULL) {
                                        is_write_unlock(space);
                                        return MACH_RCV_INVALID_NOTIFY;
                                }
                        } else
                                notify_port = IP_NULL;

                        if ((reply_type != MACH_MSG_TYPE_PORT_SEND_ONCE) &&
                            ipc_right_reverse(space, (ipc_object_t) reply,
                                              &reply_name, &entry)) {
                                /* reply port is locked and active */

                                /*
                                 *      We don't need the notify_port
                                 *      send-once right, but we can't release
                                 *      it here because reply port is locked.
                                 *      Wait until after the copyout to
                                 *      release the notify port right.
                                 */

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

                        ip_lock(reply);
                        if (!ip_active(reply)) {
                                ip_release(reply);
                                ip_check_unlock(reply);

                                if (notify_port != IP_NULL)
                                        ipc_port_release_sonce(notify_port);

                                ip_lock(dest);
                                is_write_unlock(space);

                                reply = IP_DEAD;
                                reply_name = MACH_PORT_DEAD;
                                goto copyout_dest;
                        }

                        reply_name = (mach_port_name_t)reply;
                        kr = ipc_entry_get(space, &reply_name, &entry);
                        if (kr != KERN_SUCCESS) {
                                ip_unlock(reply);

                                if (notify_port != IP_NULL)
                                        ipc_port_release_sonce(notify_port);

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

                                        if (kr == KERN_RESOURCE_SHORTAGE)
                                                return (MACH_RCV_HEADER_ERROR|
                                                        MACH_MSG_IPC_KERNEL);
                                        else
                                                return (MACH_RCV_HEADER_ERROR|
                                                        MACH_MSG_IPC_SPACE);
                                }
                                /* space is locked again; start over */

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

                        if (notify_port == IP_NULL) {
                                /* not making a dead-name request */

                                entry->ie_object = (ipc_object_t) reply;
                                break;
                        }

                        kr = ipc_port_dnrequest(reply, reply_name,
                                                notify_port, &request);
                        if (kr != KERN_SUCCESS) {
                                ip_unlock(reply);

                                ipc_port_release_sonce(notify_port);

                                ipc_entry_dealloc(space, reply_name, entry);
                                is_write_unlock(space);

                                ip_lock(reply);
                                if (!ip_active(reply)) {
                                        /* will fail next time around loop */

                                        ip_unlock(reply);
                                        is_write_lock(space);
                                        continue;
                                }

                                kr = ipc_port_dngrow(reply, ITS_SIZE_NONE);
                                /* port is unlocked */
                                if (kr != KERN_SUCCESS)
                                        return (MACH_RCV_HEADER_ERROR|
                                                MACH_MSG_IPC_KERNEL);

                                is_write_lock(space);
                                continue;
                        }

                        notify_port = IP_NULL; /* don't release right below */

                        entry->ie_object = (ipc_object_t) reply;
                        entry->ie_request = request;
                        break;
                }

                /* space and reply port are locked and active */

                ip_reference(reply);    /* hold onto the reply port */

                kr = ipc_right_copyout(space, reply_name, entry,
                                       reply_type, TRUE, (ipc_object_t) reply);
                /* reply port is unlocked */
                assert(kr == KERN_SUCCESS);

                if (notify_port != IP_NULL)
                        ipc_port_release_sonce(notify_port);

                ip_lock(dest);
                is_write_unlock(space);
        } else {
                /*
                 *      No reply port!  This is an easy case.
                 *      We only need to have the space locked
                 *      when checking notify and when locking
                 *      the destination (to ensure atomicity).
                 */

                is_read_lock(space);
                if (!space->is_active) {
                        is_read_unlock(space);
                        return MACH_RCV_HEADER_ERROR|MACH_MSG_IPC_SPACE;
                }

                if (notify != MACH_PORT_NULL) {
                        ipc_entry_t entry;

                        /* must check notify even though it won't be used */

                        if ((entry = ipc_entry_lookup(space, notify)) == IE_NULL) {
                                is_read_unlock(space);
                                return MACH_RCV_INVALID_NOTIFY;
                        }
        
                        if ((entry->ie_bits & MACH_PORT_TYPE_RECEIVE) == 0) {
                                is_read_unlock(space);
                                return MACH_RCV_INVALID_NOTIFY;
                        }
                }

                ip_lock(dest);
                is_read_unlock(space);

                reply_name = (mach_port_name_t) reply;
        }

        /*
         *      At this point, the space is unlocked and the destination
         *      port is locked.  (Lock taken while space was locked.)
         *      reply_name is taken care of; we still need dest_name.
         *      We still hold a ref for reply (if it is valid).
         *
         *      If the space holds receive rights for the destination,
         *      we return its name for the right.  Otherwise the task
         *      managed to destroy or give away the receive right between
         *      receiving the message and this copyout.  If the destination
         *      is dead, return MACH_PORT_DEAD, and if the receive right
         *      exists somewhere else (another space, in transit)
         *      return MACH_PORT_NULL.
         *
         *      Making this copyout operation atomic with the previous
         *      copyout of the reply port is a bit tricky.  If there was
         *      no real reply port (it wasn't IP_VALID) then this isn't
         *      an issue.  If the reply port was dead at copyout time,
         *      then we are OK, because if dest is dead we serialize
         *      after the death of both ports and if dest is alive
         *      we serialize after reply died but before dest's (later) death.
         *      So assume reply was alive when we copied it out.  If dest
         *      is alive, then we are OK because we serialize before
         *      the ports' deaths.  So assume dest is dead when we look at it.
         *      If reply dies/died after dest, then we are OK because
         *      we serialize after dest died but before reply dies.
         *      So the hard case is when reply is alive at copyout,
         *      dest is dead at copyout, and reply died before dest died.
         *      In this case pretend that dest is still alive, so
         *      we serialize while both ports are alive.
         *
         *      Because the space lock is held across the copyout of reply
         *      and locking dest, the receive right for dest can't move
         *      in or out of the space while the copyouts happen, so
         *      that isn't an atomicity problem.  In the last hard case
         *      above, this implies that when dest is dead that the
         *      space couldn't have had receive rights for dest at
         *      the time reply was copied-out, so when we pretend
         *      that dest is still alive, we can return MACH_PORT_NULL.
         *
         *      If dest == reply, then we have to make it look like
         *      either both copyouts happened before the port died,
         *      or both happened after the port died.  This special
         *      case works naturally if the timestamp comparison
         *      is done correctly.
         */

    copyout_dest:

        if (ip_active(dest)) {
                ipc_object_copyout_dest(space, (ipc_object_t) dest,
                                        dest_type, &dest_name);
                /* dest is unlocked */
        } else {
                ipc_port_timestamp_t timestamp;

                timestamp = dest->ip_timestamp;
                ip_release(dest);
                ip_check_unlock(dest);

                if (IP_VALID(reply)) {
                        ip_lock(reply);
                        if (ip_active(reply) ||
                            IP_TIMESTAMP_ORDER(timestamp,
                                               reply->ip_timestamp))
                                dest_name = MACH_PORT_DEAD;
                        else
                                dest_name = MACH_PORT_NULL;
                        ip_unlock(reply);
                } else
                        dest_name = MACH_PORT_DEAD;
        }

        if (IP_VALID(reply))
                ipc_port_release(reply);

        msg->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
                          MACH_MSGH_BITS(reply_type, dest_type));
        msg->msgh_local_port = (ipc_port_t)dest_name;
        msg->msgh_remote_port = (ipc_port_t)reply_name;
    }

        return MACH_MSG_SUCCESS;
}

/*
 *      Routine:        ipc_kmsg_copyout_object
 *      Purpose:
 *              Copy-out a port right.  Always returns a name,
 *              even for unsuccessful return codes.  Always
 *              consumes the supplied object.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        The space acquired the right
 *                      (name is valid) or the object is dead (MACH_PORT_DEAD).
 *              MACH_MSG_IPC_SPACE      No room in space for the right,
 *                      or the space is dead.  (Name is MACH_PORT_NULL.)
 *              MACH_MSG_IPC_KERNEL     Kernel resource shortage.
 *                      (Name is MACH_PORT_NULL.)
 */

mach_msg_return_t
ipc_kmsg_copyout_object(
        ipc_space_t             space,
        ipc_object_t            object,
        mach_msg_type_name_t    msgt_name,
        mach_port_name_t        *namep)
{
        kern_return_t kr;

        if (!IO_VALID(object)) {
                *namep = (mach_port_name_t) object;
                return MACH_MSG_SUCCESS;
        }

        kr = ipc_object_copyout(space, object, msgt_name, TRUE, namep);
        if (kr != KERN_SUCCESS) {
                ipc_object_destroy(object, msgt_name);

                if (kr == KERN_INVALID_CAPABILITY)
                        *namep = MACH_PORT_DEAD;
                else {
                        *namep = MACH_PORT_NULL;

                        if (kr == KERN_RESOURCE_SHORTAGE)
                                return MACH_MSG_IPC_KERNEL;
                        else
                                return MACH_MSG_IPC_SPACE;
                }
        }

        return MACH_MSG_SUCCESS;
}

/*
 *      Routine:        ipc_kmsg_copyout_body
 *      Purpose:
 *              "Copy-out" port rights and out-of-line memory
 *              in the body of a message.
 *
 *              The error codes are a combination of special bits.
 *              The copyout proceeds despite errors.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Successful copyout.
 *              MACH_MSG_IPC_SPACE      No room for port right in name space.
 *              MACH_MSG_VM_SPACE       No room for memory in address space.
 *              MACH_MSG_IPC_KERNEL     Resource shortage handling port right.
 *              MACH_MSG_VM_KERNEL      Resource shortage handling memory.
 *              MACH_MSG_INVALID_RT_DESCRIPTOR Descriptor incompatible with RT
 */

mach_msg_return_t
ipc_kmsg_copyout_body(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        vm_map_t                map,
        mach_msg_body_t         *slist)
{
    mach_msg_body_t             *body;
    mach_msg_descriptor_t       *daddr, *naddr;
    mach_msg_descriptor_t       *saddr;
    mach_msg_type_number_t      i, dsc_count, sdsc_count;
    mach_msg_return_t           mr = MACH_MSG_SUCCESS;
    kern_return_t               kr;
    void                        *data;
    boolean_t                   differs = MAP_SIZE_DIFFERS(map);

    body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
    dsc_count = body->msgh_descriptor_count;
    daddr = (mach_msg_descriptor_t *) (body + 1);

    /*
     * Do scatter list setup
     */
    if (slist != MACH_MSG_BODY_NULL) {
        saddr = (mach_msg_descriptor_t *) (slist + 1);
        sdsc_count = slist->msgh_descriptor_count;
    }
    else {
        saddr = MACH_MSG_DESCRIPTOR_NULL;
        sdsc_count = 0;
    }

    /*
     * Compute the true size of the resulting descriptors
     * after potential expansion and adjust the header
     * and body location accordingly.
     */
    if (differs) {
        mach_msg_size_t dsc_adjust;

        naddr = daddr;
        dsc_adjust = 0;
        for (i = 0; i < dsc_count; i++, naddr++)
            switch (naddr->type.type) {
            case MACH_MSG_OOL_DESCRIPTOR:
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_PORTS_DESCRIPTOR:
                dsc_adjust += DESC_SIZE_ADJUSTMENT;
                break;
            default:
                break;
            }
        if (dsc_adjust) {
            mach_msg_base_t *old_base = (mach_msg_base_t *)kmsg->ikm_header;
            mach_msg_base_t *new_base;

            new_base = (mach_msg_base_t *)((vm_offset_t)old_base - dsc_adjust);
            memmove(new_base, old_base, sizeof(mach_msg_base_t));
            kmsg->ikm_header = &new_base->header;
            kmsg->ikm_header->msgh_size += dsc_adjust;
            naddr = (mach_msg_descriptor_t *)(new_base + 1);
        } else {
            naddr = daddr;
        }
    } else {
        naddr = daddr;
    }

    /*
     * Now process the descriptors
     */
    for ( i = 0; i < dsc_count; i++, daddr++ ) {
        switch (daddr->type.type) {
            
            case MACH_MSG_PORT_DESCRIPTOR: {
                volatile mach_msg_port_descriptor_t *dsc;
                volatile mach_msg_port_descriptor_t *user_dsc;
                mach_port_t                     port;
                mach_port_name_t                name;
                mach_msg_type_name_t            disp;
                
                /* 
                 * Copyout port right carried in the message 
                 */
                dsc = &daddr->port;
                user_dsc = &naddr->port;
                port = dsc->name;
                disp = dsc->disposition;
                mr |= ipc_kmsg_copyout_object(space, 
                                              (ipc_object_t)port, 
                                              disp, 
                                              &name);
                user_dsc->name = (mach_port_t)name;
                user_dsc->disposition = disp;
                user_dsc->type = MACH_MSG_PORT_DESCRIPTOR;
                naddr++;
                break;
            }

            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR : {
                vm_map_copy_t                   copy;
                mach_vm_offset_t                rcv_addr;
                mach_msg_ool_descriptor_t       *dsc;
                mach_msg_copy_options_t         copy_options;
                mach_msg_size_t                 size;
                mach_msg_descriptor_type_t      dsc_type;

                SKIP_PORT_DESCRIPTORS(saddr, sdsc_count);

                dsc = &daddr->out_of_line;
                copy = (vm_map_copy_t) dsc->address;
                size = dsc->size;
                copy_options = dsc->copy;
                assert(copy_options != MACH_MSG_KALLOC_COPY_T);
                dsc_type = dsc->type;

                if (copy != VM_MAP_COPY_NULL) {
                    /*
                     * Check to see if there is an overwrite descriptor
                     * specified in the scatter list for this ool data.
                     * The descriptor has already been verified.
                     */
                    if (saddr != MACH_MSG_DESCRIPTOR_NULL) {
                        if (differs) {
                            OTHER_OOL_DESCRIPTOR *scatter_dsc;

                            scatter_dsc = (OTHER_OOL_DESCRIPTOR *)saddr;
                            if (scatter_dsc->copy == MACH_MSG_OVERWRITE) {
                                rcv_addr = (mach_vm_offset_t) scatter_dsc->address;
                                copy_options = MACH_MSG_OVERWRITE;
                            } else {
                                rcv_addr = 0;
                                copy_options = MACH_MSG_VIRTUAL_COPY;
                            }
                        } else {
                            mach_msg_ool_descriptor_t *scatter_dsc;

                            scatter_dsc = &saddr->out_of_line;
                            if (scatter_dsc->copy == MACH_MSG_OVERWRITE) {
                                rcv_addr = CAST_USER_ADDR_T(scatter_dsc->address);
                                copy_options = MACH_MSG_OVERWRITE;
                            } else {
                                rcv_addr = 0;
                                copy_options = MACH_MSG_VIRTUAL_COPY;
                            }
                        }
                        INCREMENT_SCATTER(saddr, sdsc_count, differs);
                    }


                    /*
                     * Whether the data was virtually or physically
                     * copied we have a vm_map_copy_t for it.
                     * If there's an overwrite region specified
                     * overwrite it, otherwise do a virtual copy out.
                     */
                    if (copy_options == MACH_MSG_OVERWRITE) {
                            kr = vm_map_copy_overwrite(map, rcv_addr,
                                            copy, TRUE);
                    } else {
                            kr = vm_map_copyout(map, &rcv_addr, copy);
                    }   
                    if (kr != KERN_SUCCESS) {
                            if (kr == KERN_RESOURCE_SHORTAGE)
                                    mr |= MACH_MSG_VM_KERNEL;
                            else
                                    mr |= MACH_MSG_VM_SPACE;
                            vm_map_copy_discard(copy);
                            rcv_addr = 0;
                            size = 0;
                    }
                } else {
                    rcv_addr = 0;
                    size = 0;
                }

                /*
                 * Now update the descriptor as the user would see it.
                 * This may require expanding the descriptor to the user
                 * visible size.  There is already space allocated for
                 * this in what naddr points to.
                 */
                if (differs) {
                    volatile OTHER_OOL_DESCRIPTOR *user_dsc;
                    
                    user_dsc = (OTHER_OOL_DESCRIPTOR *)naddr;
                    user_dsc->address = rcv_addr;
                    user_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
                                           TRUE : FALSE;
                    user_dsc->copy = copy_options;
                    user_dsc->type = dsc_type;
                    user_dsc->size = size;
                    naddr = (mach_msg_descriptor_t *)((OTHER_OOL_DESCRIPTOR *)naddr + 1);
                } else {
                    volatile mach_msg_ool_descriptor_t *user_dsc;
                    
                    user_dsc = &naddr->out_of_line;
                    user_dsc->address = CAST_DOWN(void *, rcv_addr);
                    user_dsc->size = size;
                    user_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
                                           TRUE : FALSE;
                    user_dsc->copy = copy_options;
                    user_dsc->type = dsc_type;
                    naddr++;
                }
                break;
            }

            case MACH_MSG_OOL_PORTS_DESCRIPTOR : {
                mach_vm_offset_t                rcv_addr;
                mach_port_name_t                *objects;
                mach_msg_type_name_t            disp;
                mach_msg_type_number_t          count, j;
                vm_size_t                       length;

                volatile mach_msg_ool_ports_descriptor_t        *dsc;
                mach_msg_copy_options_t copy_options = MACH_MSG_VIRTUAL_COPY;

                SKIP_PORT_DESCRIPTORS(saddr, sdsc_count);

                dsc = &daddr->ool_ports;
                count = dsc->count;
                disp = dsc->disposition;
                length = count * sizeof(mach_port_name_t);

                if (length != 0 && dsc->address != 0) {

                    /*
                     * Check to see if there is an overwrite descriptor
                     * specified in the scatter list for this ool data.
                     * The descriptor has already been verified.
                     */
                    if (saddr != MACH_MSG_DESCRIPTOR_NULL) {
                        if (differs) {
                            OTHER_OOL_DESCRIPTOR *scatter_dsc;

                            scatter_dsc = (OTHER_OOL_DESCRIPTOR *)saddr;
                            rcv_addr = (mach_vm_offset_t) scatter_dsc->address;
                            copy_options = scatter_dsc->copy;
                        } else {
                            mach_msg_ool_descriptor_t *scatter_dsc;

                            scatter_dsc = &saddr->out_of_line;
                            rcv_addr = CAST_USER_ADDR_T(scatter_dsc->address);
                            copy_options = scatter_dsc->copy;
                        }
                        INCREMENT_SCATTER(saddr, sdsc_count, differs);
                    }

                    if (copy_options == MACH_MSG_VIRTUAL_COPY) {
                        /*
                         * Dynamically allocate the region
                         */
                        int anywhere = VM_MAKE_TAG(VM_MEMORY_MACH_MSG)|
                                       VM_FLAGS_ANYWHERE;

                        if ((kr = mach_vm_allocate(map, &rcv_addr, 
                                              (mach_vm_size_t)length,
                                              anywhere)) != KERN_SUCCESS) {
                            ipc_kmsg_clean_body(kmsg, 1, daddr);
                            rcv_addr = 0;

                            if (kr == KERN_RESOURCE_SHORTAGE){
                                mr |= MACH_MSG_VM_KERNEL;
                            } else {
                                mr |= MACH_MSG_VM_SPACE;
                            }
                        }
                    }


                    /*
                     * Handle the port rights and copy out the names
                     * for those rights out to user-space.
                     */
                    if (rcv_addr != 0) {
                        objects = (mach_port_name_t *) dsc->address ;
                
                        /* copyout port rights carried in the message */
                
                        for ( j = 0; j < count ; j++) {
                            ipc_object_t object =
                                (ipc_object_t) objects[j];
                    
                            mr |= ipc_kmsg_copyout_object(space, object,
                                                          disp, &objects[j]);
                        }

                        /* copyout to memory allocated above */
                        data = dsc->address;
                        if (copyoutmap(map, data, rcv_addr, length) != KERN_SUCCESS)
                            mr |= MACH_MSG_VM_SPACE;
                        kfree(data, length);
                    }
                } else {
                    rcv_addr = 0;
                }

                /*
                 * Now update the descriptor based on the information
                 * calculated above.
                 */
                if (differs) {
                    volatile OTHER_OOL_PORTS_DESCRIPTOR *user_dsc;
                    
                    user_dsc = (OTHER_OOL_PORTS_DESCRIPTOR *)naddr;
                    user_dsc->address = rcv_addr;
                    user_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
                                           TRUE : FALSE;
                    user_dsc->copy = copy_options;
                    user_dsc->disposition = disp;
                    user_dsc->type = MACH_MSG_OOL_PORTS_DESCRIPTOR;
                    user_dsc->count = count;
                    naddr = (mach_msg_descriptor_t *)((OTHER_OOL_PORTS_DESCRIPTOR *)naddr + 1);
                } else {
                    volatile mach_msg_ool_ports_descriptor_t *user_dsc;
                    
                    user_dsc = &naddr->ool_ports;
                    user_dsc->address = CAST_DOWN(void *, rcv_addr);
                    user_dsc->count = count;
                    user_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
                                           TRUE : FALSE;
                    user_dsc->copy = copy_options;
                    user_dsc->disposition = disp;
                    user_dsc->type = MACH_MSG_OOL_PORTS_DESCRIPTOR;
                    naddr++;
                }
                break;
            }
            default : {
                panic("untyped IPC copyout body: invalid message descriptor");
            }
        }
    }
    return mr;
}

/*
 *      Routine:        ipc_kmsg_copyout_size
 *      Purpose:
 *              Compute the size of the message as copied out to the given
 *              map. If the destination map's pointers are a different size
 *              than the kernel's, we have to allow for expansion/
 *              contraction of the descriptors as appropriate.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              size of the message as it would be received.
 */

mach_msg_size_t
ipc_kmsg_copyout_size(
        ipc_kmsg_t              kmsg,
        vm_map_t                map)
{
        mach_msg_size_t         send_size;

        send_size = kmsg->ikm_header->msgh_size;

        if ((kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_COMPLEX) &&
            MAP_SIZE_DIFFERS(map)) {

                mach_msg_body_t *body;
                mach_msg_descriptor_t *saddr, *eaddr;

                body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
                saddr = (mach_msg_descriptor_t *) (body + 1);
                eaddr = saddr + body->msgh_descriptor_count;
                
                for ( ; saddr < eaddr; saddr++ ) {
                        switch (saddr->type.type) {

                        case MACH_MSG_OOL_DESCRIPTOR:
                        case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
                        case MACH_MSG_OOL_PORTS_DESCRIPTOR:
                                send_size += DESC_SIZE_ADJUSTMENT;
                                break;

                        default:
                                break;
                        }
                }
        }
        return send_size;
}

/*
 *      Routine:        ipc_kmsg_copyout
 *      Purpose:
 *              "Copy-out" port rights and out-of-line memory
 *              in the message.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Copied out all rights and memory.
 *              MACH_RCV_INVALID_NOTIFY Bad notify port.
 *                      Rights and memory in the message are intact.
 *              MACH_RCV_HEADER_ERROR + special bits
 *                      Rights and memory in the message are intact.
 *              MACH_RCV_BODY_ERROR + special bits
 *                      The message header was successfully copied out.
 *                      As much of the body was handled as possible.
 */

mach_msg_return_t
ipc_kmsg_copyout(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        vm_map_t                map,
        mach_port_name_t        notify,
        mach_msg_body_t         *slist)
{
        mach_msg_return_t mr;

        mr = ipc_kmsg_copyout_header(kmsg->ikm_header, space, notify);
        if (mr != MACH_MSG_SUCCESS)
                return mr;

        if (kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_COMPLEX) {
                mr = ipc_kmsg_copyout_body(kmsg, space, map, slist);

                if (mr != MACH_MSG_SUCCESS)
                        mr |= MACH_RCV_BODY_ERROR;
        }

        return mr;
}

/*
 *      Routine:        ipc_kmsg_copyout_pseudo
 *      Purpose:
 *              Does a pseudo-copyout of the message.
 *              This is like a regular copyout, except
 *              that the ports in the header are handled
 *              as if they are in the body.  They aren't reversed.
 *
 *              The error codes are a combination of special bits.
 *              The copyout proceeds despite errors.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              MACH_MSG_SUCCESS        Successful copyout.
 *              MACH_MSG_IPC_SPACE      No room for port right in name space.
 *              MACH_MSG_VM_SPACE       No room for memory in address space.
 *              MACH_MSG_IPC_KERNEL     Resource shortage handling port right.
 *              MACH_MSG_VM_KERNEL      Resource shortage handling memory.
 */

mach_msg_return_t
ipc_kmsg_copyout_pseudo(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        vm_map_t                map,
        mach_msg_body_t         *slist)
{
        mach_msg_bits_t mbits = kmsg->ikm_header->msgh_bits;
        ipc_object_t dest = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        ipc_object_t reply = (ipc_object_t) kmsg->ikm_header->msgh_local_port;
        mach_msg_type_name_t dest_type = MACH_MSGH_BITS_REMOTE(mbits);
        mach_msg_type_name_t reply_type = MACH_MSGH_BITS_LOCAL(mbits);
        mach_port_name_t dest_name, reply_name;
        mach_msg_return_t mr;

        assert(IO_VALID(dest));

        mr = (ipc_kmsg_copyout_object(space, dest, dest_type, &dest_name) |
              ipc_kmsg_copyout_object(space, reply, reply_type, &reply_name));

        kmsg->ikm_header->msgh_bits = mbits &~ MACH_MSGH_BITS_CIRCULAR;
        kmsg->ikm_header->msgh_remote_port = (ipc_port_t)dest_name;
        kmsg->ikm_header->msgh_local_port = (ipc_port_t)reply_name;

        if (mbits & MACH_MSGH_BITS_COMPLEX) {
                mr |= ipc_kmsg_copyout_body(kmsg, space, map, slist);
        }

        return mr;
}

/*
 *      Routine:        ipc_kmsg_copyout_dest
 *      Purpose:
 *              Copies out the destination port in the message.
 *              Destroys all other rights and memory in the message.
 *      Conditions:
 *              Nothing locked.
 */

void
ipc_kmsg_copyout_dest(
        ipc_kmsg_t      kmsg,
        ipc_space_t     space)
{
        mach_msg_bits_t mbits;
        ipc_object_t dest;
        ipc_object_t reply;
        mach_msg_type_name_t dest_type;
        mach_msg_type_name_t reply_type;
        mach_port_name_t dest_name, reply_name;

        mbits = kmsg->ikm_header->msgh_bits;
        dest = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        reply = (ipc_object_t) kmsg->ikm_header->msgh_local_port;
        dest_type = MACH_MSGH_BITS_REMOTE(mbits);
        reply_type = MACH_MSGH_BITS_LOCAL(mbits);

        assert(IO_VALID(dest));

        io_lock(dest);
        if (io_active(dest)) {
                ipc_object_copyout_dest(space, dest, dest_type, &dest_name);
                /* dest is unlocked */
        } else {
                io_release(dest);
                io_check_unlock(dest);
                dest_name = MACH_PORT_DEAD;
        }

        if (IO_VALID(reply)) {
                ipc_object_destroy(reply, reply_type);
                reply_name = MACH_PORT_NULL;
        } else
                reply_name = (mach_port_name_t) reply;

        kmsg->ikm_header->msgh_bits = (MACH_MSGH_BITS_OTHER(mbits) |
                                      MACH_MSGH_BITS(reply_type, dest_type));
        kmsg->ikm_header->msgh_local_port = (ipc_port_t)dest_name;
        kmsg->ikm_header->msgh_remote_port = (ipc_port_t)reply_name;

        if (mbits & MACH_MSGH_BITS_COMPLEX) {
                mach_msg_body_t *body;

                body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
                ipc_kmsg_clean_body(kmsg, body->msgh_descriptor_count, 
                                    (mach_msg_descriptor_t *)(body + 1));
        }
}

/*
 *      Routine:        ipc_kmsg_copyin_scatter
 *      Purpose:
 *              allocate and copyin a scatter list
 *      Algorithm:
 *              The gather (kmsg) is valid since it has been copied in.
 *              Gather list descriptors are sequentially paired with scatter
 *              list descriptors, with port descriptors in either list ignored.
 *              Descriptors are consistent if the type fileds match and size
 *              of the scatter descriptor is less than or equal to the
 *              size of the gather descriptor.  A MACH_MSG_ALLOCATE copy
 *              strategy in a scatter descriptor matches any size in the
 *              corresponding gather descriptor assuming they are the same type.
 *              Either list may be larger than the other.  During the
 *              subsequent copy out, excess scatter descriptors are ignored
 *              and excess gather descriptors default to dynamic allocation.
 *
 *              In the case of a size error, the scatter list is released.
 *      Conditions:
 *              Nothing locked.
 *      Returns:
 *              the allocated message body containing the scatter list.
 */

mach_msg_body_t *
ipc_kmsg_get_scatter(
        mach_vm_address_t       msg_addr,
       mach_msg_size_t         slist_size,
        ipc_kmsg_t              kmsg)
{
        mach_msg_body_t         *slist;
        mach_msg_body_t         *body;
        mach_msg_descriptor_t   *gstart, *gend;
        mach_msg_descriptor_t   *sstart, *send;


        if (slist_size < sizeof(mach_msg_base_t))
                return MACH_MSG_BODY_NULL;

        slist_size -= sizeof(mach_msg_header_t);
        slist = (mach_msg_body_t *)kalloc(slist_size);
        if (slist == MACH_MSG_BODY_NULL)
                return slist;

        if (copyin(msg_addr + sizeof(mach_msg_header_t), (char *)slist, slist_size)) {
                kfree(slist, slist_size);
                return MACH_MSG_BODY_NULL;
        }

        if ((slist->msgh_descriptor_count* sizeof(mach_msg_descriptor_t)
             + sizeof(mach_msg_size_t)) > slist_size) {
                kfree(slist, slist_size);
                return MACH_MSG_BODY_NULL;
        }

        body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
        gstart = (mach_msg_descriptor_t *) (body + 1);
        gend = gstart + body->msgh_descriptor_count;

        sstart = (mach_msg_descriptor_t *) (slist + 1);
        send = sstart + slist->msgh_descriptor_count;

        while (gstart < gend) {
            mach_msg_descriptor_type_t  g_type;

            /*
             * Skip port descriptors in gather list.
             */
            g_type = gstart->type.type;

            if (g_type != MACH_MSG_PORT_DESCRIPTOR) {

              /*
               * A scatter list with a 0 descriptor count is treated as an
               * automatic size mismatch.
               */
              if (slist->msgh_descriptor_count == 0) {
                        kfree(slist, slist_size);
                        return MACH_MSG_BODY_NULL;
              }

              /*
               * Skip port descriptors in  scatter list.
               */
              while (sstart < send) {
                    if (sstart->type.type != MACH_MSG_PORT_DESCRIPTOR)
                        break;
                    sstart++;
              }

              /*
               * No more scatter descriptors, we're done
               */
              if (sstart >= send) {
                    break;
              }

              /*
               * Check type, copy and size fields
               */
                if (g_type == MACH_MSG_OOL_DESCRIPTOR ||
                    g_type == MACH_MSG_OOL_VOLATILE_DESCRIPTOR) {
                    if (sstart->type.type != MACH_MSG_OOL_DESCRIPTOR &&
                        sstart->type.type != MACH_MSG_OOL_VOLATILE_DESCRIPTOR) {
                        kfree(slist, slist_size);
                        return MACH_MSG_BODY_NULL;
                    }
                    if (sstart->out_of_line.copy == MACH_MSG_OVERWRITE &&
                        gstart->out_of_line.size > sstart->out_of_line.size) {
                        kfree(slist, slist_size);
                        return MACH_MSG_BODY_NULL;
                    }
                }
                else {
                  if (sstart->type.type != MACH_MSG_OOL_PORTS_DESCRIPTOR) {
                        kfree(slist, slist_size);
                        return MACH_MSG_BODY_NULL;
                  }
                    if (sstart->ool_ports.copy == MACH_MSG_OVERWRITE &&
                        gstart->ool_ports.count > sstart->ool_ports.count) {
                        kfree(slist, slist_size);
                        return MACH_MSG_BODY_NULL;
                    }
                }
                sstart++;
            }
            gstart++;
        }
        return slist;
}


/*
 *      Routine:        ipc_kmsg_free_scatter
 *      Purpose:
 *              Deallocate a scatter list.  Since we actually allocated
 *              a body without a header, and since the header was originally
 *              accounted for in slist_size, we have to ajust it down
 *              before freeing the scatter list.
 */
void
ipc_kmsg_free_scatter(
        mach_msg_body_t *slist,
        mach_msg_size_t slist_size)
{
        slist_size -= sizeof(mach_msg_header_t);
        kfree(slist, slist_size);
}


/*
 *      Routine:        ipc_kmsg_copyout_to_kernel
 *      Purpose:
 *              Copies out the destination and reply ports in the message.
 *              Leaves all other rights and memory in the message alone.
 *      Conditions:
 *              Nothing locked.
 *
 *      Derived from ipc_kmsg_copyout_dest.
 *      Use by mach_msg_rpc_from_kernel (which used to use copyout_dest).
 *      We really do want to save rights and memory.
 */

void
ipc_kmsg_copyout_to_kernel(
        ipc_kmsg_t      kmsg,
        ipc_space_t     space)
{
        ipc_object_t dest;
        ipc_object_t reply;
        mach_msg_type_name_t dest_type;
        mach_msg_type_name_t reply_type;
        mach_port_name_t dest_name, reply_name;

        dest = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        reply = (ipc_object_t) kmsg->ikm_header->msgh_local_port;
        dest_type = MACH_MSGH_BITS_REMOTE(kmsg->ikm_header->msgh_bits);
        reply_type = MACH_MSGH_BITS_LOCAL(kmsg->ikm_header->msgh_bits);

        assert(IO_VALID(dest));

        io_lock(dest);
        if (io_active(dest)) {
                ipc_object_copyout_dest(space, dest, dest_type, &dest_name);
                /* dest is unlocked */
        } else {
                io_release(dest);
                io_check_unlock(dest);
                dest_name = MACH_PORT_DEAD;
        }

        reply_name = (mach_port_name_t) reply;

        kmsg->ikm_header->msgh_bits =
                (MACH_MSGH_BITS_OTHER(kmsg->ikm_header->msgh_bits) |
                                        MACH_MSGH_BITS(reply_type, dest_type));
        kmsg->ikm_header->msgh_local_port = (ipc_port_t)dest_name;
        kmsg->ikm_header->msgh_remote_port = (ipc_port_t)reply_name;
}

#include <mach_kdb.h>
#if     MACH_KDB

#include <ddb/db_output.h>
#include <ipc/ipc_print.h>
/*
 * Forward declarations
 */
void ipc_msg_print_untyped(
        mach_msg_body_t         *body);

const char * ipc_type_name(
        int             type_name,
        boolean_t       received);

void ipc_print_type_name(
        int     type_name);

const char *
msgh_bit_decode(
        mach_msg_bits_t bit);

const char *
mm_copy_options_string(
        mach_msg_copy_options_t option);

void db_print_msg_uid(mach_msg_header_t *);


const char *
ipc_type_name(
        int             type_name,
        boolean_t       received)
{
        switch (type_name) {
                case MACH_MSG_TYPE_PORT_NAME:
                return "port_name";
                
                case MACH_MSG_TYPE_MOVE_RECEIVE:
                if (received) {
                        return "port_receive";
                } else {
                        return "move_receive";
                }
                
                case MACH_MSG_TYPE_MOVE_SEND:
                if (received) {
                        return "port_send";
                } else {
                        return "move_send";
                }
                
                case MACH_MSG_TYPE_MOVE_SEND_ONCE:
                if (received) {
                        return "port_send_once";
                } else {
                        return "move_send_once";
                }
                
                case MACH_MSG_TYPE_COPY_SEND:
                return "copy_send";
                
                case MACH_MSG_TYPE_MAKE_SEND:
                return "make_send";
                
                case MACH_MSG_TYPE_MAKE_SEND_ONCE:
                return "make_send_once";
                
                default:
                return (char *) 0;
        }
}
                
void
ipc_print_type_name(
        int     type_name)
{
        const char *name = ipc_type_name(type_name, TRUE);
        if (name) {
                printf("%s", name);
        } else {
                printf("type%d", type_name);
        }
}

/*
 * ipc_kmsg_print       [ debug ]
 */
void
ipc_kmsg_print(
        ipc_kmsg_t      kmsg)
{
        iprintf("kmsg=0x%x\n", kmsg);
        iprintf("ikm_next=0x%x, prev=0x%x, size=%d",
                kmsg->ikm_next,
                kmsg->ikm_prev,
                kmsg->ikm_size);
        printf("\n");
        ipc_msg_print(kmsg->ikm_header);
}

const char *
msgh_bit_decode(
        mach_msg_bits_t bit)
{
        switch (bit) {
            case MACH_MSGH_BITS_COMPLEX:        return "complex";
            case MACH_MSGH_BITS_CIRCULAR:       return "circular";
            default:                            return (char *) 0;
        }
}

/*
 * ipc_msg_print        [ debug ]
 */
void
ipc_msg_print(
        mach_msg_header_t       *msgh)
{
        mach_msg_bits_t mbits;
        unsigned int    bit, i;
        const char      *bit_name;
        int             needs_comma;

        mbits = msgh->msgh_bits;
        iprintf("msgh_bits=0x%x:  l=0x%x,r=0x%x\n",
                mbits,
                MACH_MSGH_BITS_LOCAL(msgh->msgh_bits),
                MACH_MSGH_BITS_REMOTE(msgh->msgh_bits));

        mbits = MACH_MSGH_BITS_OTHER(mbits) & MACH_MSGH_BITS_USED;
        db_indent += 2;
        if (mbits)
                iprintf("decoded bits:  ");
        needs_comma = 0;
        for (i = 0, bit = 1; i < sizeof(mbits) * 8; ++i, bit <<= 1) {
                if ((mbits & bit) == 0)
                        continue;
                bit_name = msgh_bit_decode((mach_msg_bits_t)bit);
                if (bit_name)
                        printf("%s%s", needs_comma ? "," : "", bit_name);
                else
                        printf("%sunknown(0x%x),", needs_comma ? "," : "", bit);
                ++needs_comma;
        }
        if (msgh->msgh_bits & ~MACH_MSGH_BITS_USED) {
                printf("%sunused=0x%x,", needs_comma ? "," : "",
                       msgh->msgh_bits & ~MACH_MSGH_BITS_USED);
        }
        printf("\n");
        db_indent -= 2;

        needs_comma = 1;
        if (msgh->msgh_remote_port) {
                iprintf("remote=0x%x(", msgh->msgh_remote_port);
                ipc_print_type_name(MACH_MSGH_BITS_REMOTE(msgh->msgh_bits));
                printf(")");
        } else {
                iprintf("remote=null");
        }

        if (msgh->msgh_local_port) {
                printf("%slocal=0x%x(", needs_comma ? "," : "",
                       msgh->msgh_local_port);
                ipc_print_type_name(MACH_MSGH_BITS_LOCAL(msgh->msgh_bits));
                printf(")\n");
        } else {
                printf("local=null\n");
        }

        iprintf("msgh_id=%d, size=%d\n",
                msgh->msgh_id,
                msgh->msgh_size);

        if (mbits & MACH_MSGH_BITS_COMPLEX) {   
                ipc_msg_print_untyped((mach_msg_body_t *) (msgh + 1));
        }
}


const char *
mm_copy_options_string(
        mach_msg_copy_options_t option)
{
        const char      *name;

        switch (option) {
            case MACH_MSG_PHYSICAL_COPY:
                name = "PHYSICAL";
                break;
            case MACH_MSG_VIRTUAL_COPY:
                name = "VIRTUAL";
                break;
            case MACH_MSG_OVERWRITE:
                name = "OVERWRITE";
                break;
            case MACH_MSG_ALLOCATE:
                name = "ALLOCATE";
                break;
            case MACH_MSG_KALLOC_COPY_T:
                name = "KALLOC_COPY_T";
                break;
            default:
                name = "unknown";
                break;
        }
        return name;
}

void
ipc_msg_print_untyped(
        mach_msg_body_t         *body)
{
    mach_msg_descriptor_t       *saddr, *send;
    mach_msg_descriptor_type_t  type;

    iprintf("%d descriptors %d: \n", body->msgh_descriptor_count);

    saddr = (mach_msg_descriptor_t *) (body + 1);
    send = saddr + body->msgh_descriptor_count;

    for ( ; saddr < send; saddr++ ) {
        
        type = saddr->type.type;

        switch (type) {
            
            case MACH_MSG_PORT_DESCRIPTOR: {
                mach_msg_port_descriptor_t *dsc;

                dsc = &saddr->port;
                iprintf("-- PORT name = 0x%x disp = ", dsc->name);
                ipc_print_type_name(dsc->disposition);
                printf("\n");
                break;
            }
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR: {
                mach_msg_ool_descriptor_t *dsc;
                
                dsc = &saddr->out_of_line;
                iprintf("-- OOL%s addr = 0x%x size = 0x%x copy = %s %s\n",
                        type == MACH_MSG_OOL_DESCRIPTOR ? "" : " VOLATILE",
                        dsc->address, dsc->size,
                        mm_copy_options_string(dsc->copy),
                        dsc->deallocate ? "DEALLOC" : "");
                break;
            } 
            case MACH_MSG_OOL_PORTS_DESCRIPTOR : {
                mach_msg_ool_ports_descriptor_t *dsc;

                dsc = &saddr->ool_ports;

                iprintf("-- OOL_PORTS addr = 0x%x count = 0x%x ",
                          dsc->address, dsc->count);
                printf("disp = ");
                ipc_print_type_name(dsc->disposition);
                printf(" copy = %s %s\n",
                       mm_copy_options_string(dsc->copy),
                       dsc->deallocate ? "DEALLOC" : "");
                break;
            }

            default: {
                iprintf("-- UNKNOWN DESCRIPTOR 0x%x\n", type);
                break;
            }
        }
    }
}
#endif  /* MACH_KDB */