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

/*
 * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * 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.
 */
/*
 * NOTICE: This file was modified by McAfee Research in 2004 to introduce
 * support for mandatory and extensible security protections.  This notice
 * is included in support of clause 2.2 (b) of the Apple Public License,
 * Version 2.0.
 * Copyright (c) 2005 SPARTA, Inc.
 */
/*
 */
/*
 *      File:   ipc/ipc_kmsg.c
 *      Author: Rich Draves
 *      Date:   1989
 *
 *      Operations on kernel messages.
 */


#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/debug.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 <machine/machlimits.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 <ipc/ipc_importance.h>

#include <security/mac_mach_internal.h>

#include <string.h>

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

#if DEBUG
#define DEBUG_MSGS_K64 1
#endif

#include <sys/kdebug.h>
#include <libkern/OSAtomic.h>

#pragma pack(4)

typedef struct 
{
  mach_msg_bits_t       msgh_bits;
  mach_msg_size_t       msgh_size;
  mach_port_name_t      msgh_remote_port;
  mach_port_name_t      msgh_local_port;
  mach_port_name_t      msgh_voucher_port;
  mach_msg_id_t         msgh_id;
} mach_msg_legacy_header_t;

typedef struct
{
        mach_msg_legacy_header_t       header;
        mach_msg_body_t         body;
} mach_msg_legacy_base_t;

typedef struct
{
  mach_port_name_t                              name;
  mach_msg_size_t                               pad1;
  uint32_t                                              pad2 : 16;
  mach_msg_type_name_t                  disposition : 8;
  mach_msg_descriptor_type_t    type : 8;
} mach_msg_legacy_port_descriptor_t;


typedef union
{
  mach_msg_legacy_port_descriptor_t                     port;
  mach_msg_ool_descriptor32_t           out_of_line32;
  mach_msg_ool_ports_descriptor32_t     ool_ports32;
  mach_msg_type_descriptor_t                    type;
} mach_msg_legacy_descriptor_t;

#pragma pack()

#define LEGACY_HEADER_SIZE_DELTA ((mach_msg_size_t)(sizeof(mach_msg_header_t) - sizeof(mach_msg_legacy_header_t)))

// END LP64 fixes


#if DEBUG_MSGS_K64
extern void ipc_pset_print64(
                        ipc_pset_t      pset);

extern void     ipc_kmsg_print64(
                        ipc_kmsg_t      kmsg,
                        const char      *str);

extern void     ipc_msg_print64(
                mach_msg_header_t       *msgh);

extern ipc_port_t ipc_name_to_data64(
                        task_t                  task,
                        mach_port_name_t        name);

/*
 * Forward declarations
 */
void ipc_msg_print_untyped64(
        mach_msg_body_t         *body);

const char * ipc_type_name64(
        int             type_name,
        boolean_t       received);

void ipc_print_type_name64(
        int     type_name);

const char *
msgh_bit_decode64(
        mach_msg_bits_t bit);

const char *
mm_copy_options_string64(
        mach_msg_copy_options_t option);

void db_print_msg_uid64(mach_msg_header_t *);

static void
ipc_msg_body_print64(void *body, int size)
{
        uint32_t        *word = (uint32_t *) body;
        uint32_t        *end  = (uint32_t *)(((uintptr_t) body) + size
                                                - sizeof(mach_msg_header_t));
        int             i;

        kprintf("  body(%p-%p):\n    %p: ", body, end, word);
        for (;;) {
                for (i = 0; i < 8; i++, word++) {
                        if (word >= end) {
                                kprintf("\n");
                                return;
                        }
                        kprintf("%08x ", *word); 
                }
                kprintf("\n    %p: ", word);
        }
}


const char *
ipc_type_name64(
        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_name64(
        int     type_name)
{
        const char *name = ipc_type_name64(type_name, TRUE);
        if (name) {
                kprintf("%s", name);
        } else {
                kprintf("type%d", type_name);
        }
}

/*
 * ipc_kmsg_print64     [ debug ]
 */
void
ipc_kmsg_print64(
        ipc_kmsg_t      kmsg,
        const char      *str)
{
        kprintf("%s kmsg=%p:\n", str, kmsg);
        kprintf("  next=%p, prev=%p, size=%d",
                kmsg->ikm_next,
                kmsg->ikm_prev,
                kmsg->ikm_size);
        kprintf("\n");
        ipc_msg_print64(kmsg->ikm_header);
}

const char *
msgh_bit_decode64(
        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_print64      [ debug ]
 */
void
ipc_msg_print64(
        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;
        kprintf("  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;
        kprintf("  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_decode64((mach_msg_bits_t)bit);
                if (bit_name)
                        kprintf("%s%s", needs_comma ? "," : "", bit_name);
                else
                        kprintf("%sunknown(0x%x),", needs_comma ? "," : "", bit);
                ++needs_comma;
        }
        if (msgh->msgh_bits & ~MACH_MSGH_BITS_USED) {
                kprintf("%sunused=0x%x,", needs_comma ? "," : "",
                       msgh->msgh_bits & ~MACH_MSGH_BITS_USED);
        }
        kprintf("\n");

        needs_comma = 1;
        if (msgh->msgh_remote_port) {
                kprintf("  remote=%p(", msgh->msgh_remote_port);
                ipc_print_type_name64(MACH_MSGH_BITS_REMOTE(msgh->msgh_bits));
                kprintf(")");
        } else {
                kprintf("  remote=null");
        }

        if (msgh->msgh_local_port) {
                kprintf("%slocal=%p(", needs_comma ? "," : "",
                       msgh->msgh_local_port);
                ipc_print_type_name64(MACH_MSGH_BITS_LOCAL(msgh->msgh_bits));
                kprintf(")\n");
        } else {
                kprintf("local=null\n");
        }

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

        if (mbits & MACH_MSGH_BITS_COMPLEX) {   
                ipc_msg_print_untyped64((mach_msg_body_t *) (msgh + 1));
        }

        ipc_msg_body_print64((void *)(msgh + 1), msgh->msgh_size);
}


const char *
mm_copy_options_string64(
        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(DEPRECATED)";
                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_untyped64(
        mach_msg_body_t         *body)
{
    mach_msg_descriptor_t       *saddr, *send;
    mach_msg_descriptor_type_t  type;

    kprintf("  %d descriptors: \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;
                kprintf("    PORT name = %p disp = ", dsc->name);
                ipc_print_type_name64(dsc->disposition);
                kprintf("\n");
                break;
            }
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR: {
                mach_msg_ool_descriptor_t *dsc;
                
                dsc = (mach_msg_ool_descriptor_t *) &saddr->out_of_line;
                kprintf("    OOL%s addr = %p size = 0x%x copy = %s %s\n",
                        type == MACH_MSG_OOL_DESCRIPTOR ? "" : " VOLATILE",
                        dsc->address, dsc->size,
                        mm_copy_options_string64(dsc->copy),
                        dsc->deallocate ? "DEALLOC" : "");
                break;
            } 
            case MACH_MSG_OOL_PORTS_DESCRIPTOR : {
                mach_msg_ool_ports_descriptor_t *dsc;

                dsc = (mach_msg_ool_ports_descriptor_t *) &saddr->ool_ports;

                kprintf("    OOL_PORTS addr = %p count = 0x%x ",
                          dsc->address, dsc->count);
                kprintf("disp = ");
                ipc_print_type_name64(dsc->disposition);
                kprintf(" copy = %s %s\n",
                       mm_copy_options_string64(dsc->copy),
                       dsc->deallocate ? "DEALLOC" : "");
                break;
            }

            default: {
                kprintf("    UNKNOWN DESCRIPTOR 0x%x\n", type);
                break;
            }
        }
    }
}

#define DEBUG_IPC_KMSG_PRINT(kmsg,string)       \
        __unreachable_ok_push   \
        if (DEBUG_KPRINT_SYSCALL_PREDICATE(DEBUG_KPRINT_SYSCALL_IPC_MASK)) {    \
                ipc_kmsg_print64(kmsg, string); \
        }       \
        __unreachable_ok_pop

#define DEBUG_IPC_MSG_BODY_PRINT(body,size)     \
        __unreachable_ok_push   \
        if (DEBUG_KPRINT_SYSCALL_PREDICATE(DEBUG_KPRINT_SYSCALL_IPC_MASK)) {    \
                ipc_msg_body_print64(body,size);\
        }       \
        __unreachable_ok_pop
#else /* !DEBUG_MSGS_K64 */
#define DEBUG_IPC_KMSG_PRINT(kmsg,string)
#define DEBUG_IPC_MSG_BODY_PRINT(body,size)
#endif  /* !DEBUG_MSGS_K64 */

extern vm_map_t         ipc_kernel_copy_map;
extern vm_size_t        ipc_kmsg_max_space;
extern vm_size_t        ipc_kmsg_max_vm_space;
extern vm_size_t        ipc_kmsg_max_body_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    ((mach_msg_size_t)(sizeof(mach_msg_ool_descriptor64_t) - \
                                 sizeof(mach_msg_ool_descriptor32_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;

        /*
         * LP64support -
         * Pad the allocation in case we need to expand the
         * message descrptors for user spaces with pointers larger than
         * the kernel's own, or vice versa.  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.
         */
        mach_msg_size_t size = msg_and_trailer_size - MAX_TRAILER_SIZE;

        /* compare against implementation upper limit for the body */
        if (size > ipc_kmsg_max_body_space)
                return IKM_NULL;

        if (size > sizeof(mach_msg_base_t)) {
                mach_msg_size_t max_desc = (mach_msg_size_t)(((size - sizeof(mach_msg_base_t)) /
                                           sizeof(mach_msg_ool_descriptor32_t)) *
                                           DESC_SIZE_ADJUSTMENT);

                /* make sure expansion won't cause wrap */
                if (msg_and_trailer_size > MACH_MSG_SIZE_MAX - max_desc)
                        return IKM_NULL;

                max_expanded_size = msg_and_trailer_size + max_desc;
        } else
          max_expanded_size = msg_and_trailer_size;

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

        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;
                        enable_preemption();
                        ikm_check_init(kmsg, max_expanded_size);
                        ikm_set_header(kmsg, 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);
                ikm_set_header(kmsg, 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;

        assert(!IP_VALID(kmsg->ikm_voucher));

        KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_IPC,MACH_IPC_KMSG_FREE) | DBG_FUNC_NONE,
                              VM_KERNEL_ADDRPERM((uintptr_t)kmsg),
                              0, 0, 0, 0);

        /*
         * 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);
                        ip_release(port);
                        return;
                }
                ip_unlock(port);
                ip_release(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) == IKM_BOGUS);
        assert((kmsg->ikm_prev = IKM_BOGUS) == 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)
{
        /*
         *      Destroying a message can cause more messages to be destroyed.
         *      Curtail recursion by putting messages on the deferred
         *      destruction queue.  If this was the first message on the
         *      queue, this instance must process the full queue.
         */
        if (ipc_kmsg_delayed_destroy(kmsg))
                ipc_kmsg_reap_delayed();
}

/*
 *      Routine:        ipc_kmsg_delayed_destroy
 *      Purpose:
 *              Enqueues a kernel message for deferred destruction.
 *      Returns:
 *              Boolean indicator that the caller is responsible to reap
 *              deferred messages.
 */

boolean_t ipc_kmsg_delayed_destroy(
        ipc_kmsg_t kmsg)
{
        ipc_kmsg_queue_t queue = &(current_thread()->ith_messages);
        boolean_t first = ipc_kmsg_queue_empty(queue);

        ipc_kmsg_enqueue(queue, kmsg);
        return first;
}

/*
 *      Routine:        ipc_kmsg_destroy_queue
 *      Purpose:
 *              Destroys messages from the per-thread
 *              deferred reaping queue.
 *      Conditions:
 *              No locks held.
 */

void
ipc_kmsg_reap_delayed(void)
{
        ipc_kmsg_queue_t queue = &(current_thread()->ith_messages);
        ipc_kmsg_t kmsg;

        /*
         * must leave kmsg in queue while cleaning it to assure
         * no nested calls recurse into here.
         */
        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_clean_body
 *      Purpose:
 *              Cleans the body of a kernel message.
 *              Releases all rights, references, and memory.
 *
 *      Conditions:
 *              No locks held.
 */
static unsigned int _ipc_kmsg_clean_invalid_desc = 0;
void
ipc_kmsg_clean_body(
        __unused ipc_kmsg_t     kmsg,
        mach_msg_type_number_t  number,
        mach_msg_descriptor_t   *saddr)
{
    mach_msg_type_number_t      i;

    if ( number == 0 )
        return;

    for (i = 0 ; i < number; i++, 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 = (mach_msg_ool_descriptor_t *)&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 = (mach_msg_ool_ports_descriptor_t  *)&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_t));
                break;
            }
            default : {
                    _ipc_kmsg_clean_invalid_desc++; /* don't understand this type of descriptor */
            }
        }
    }
}

/*
 *      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;

        /* deal with importance chain while we still have dest and voucher references */
        ipc_importance_clean(kmsg);

        object = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        assert(IO_VALID(object));
        ipc_object_destroy_dest(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));

        object = (ipc_object_t) kmsg->ikm_voucher;
        if (IO_VALID(object)) {
                assert(MACH_MSGH_BITS_VOUCHER(mbits) == MACH_MSG_TYPE_MOVE_SEND);
                ipc_object_destroy(object, MACH_MSG_TYPE_PORT_SEND);
                kmsg->ikm_voucher = IP_NULL;
        }

        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;

        /* deal with importance chain while we still have dest and voucher references */
        ipc_importance_clean(kmsg);

        mbits = kmsg->ikm_header->msgh_bits;
        object = (ipc_object_t) kmsg->ikm_header->msgh_remote_port;
        if (IO_VALID(object))
                ipc_object_destroy_dest(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));

        object = (ipc_object_t) kmsg->ikm_voucher;
        if (IO_VALID(object)) {
                assert(MACH_MSGH_BITS_VOUCHER(mbits) == MACH_MSG_TYPE_MOVE_SEND);
                ipc_object_destroy(object, MACH_MSG_TYPE_PORT_SEND);
                kmsg->ikm_voucher = IP_NULL;
        }

        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_prealloc
 *      Purpose:
 *              Wraper to ipc_kmsg_alloc() to account for
 *              header expansion requirements.
 */
ipc_kmsg_t
ipc_kmsg_prealloc(mach_msg_size_t size)
{
#if defined(__LP64__)
        if (size > MACH_MSG_SIZE_MAX - LEGACY_HEADER_SIZE_DELTA)
                return IKM_NULL;

        size += LEGACY_HEADER_SIZE_DELTA;
#endif
        return ipc_kmsg_alloc(size);
}


/*
 *      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_TOO_LARGE     Message too large to ever be sent.
 *              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;
        mach_msg_legacy_base_t      legacy_base;
        mach_msg_size_t             len_copied;
        legacy_base.body.msgh_descriptor_count = 0;

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

        if (size > ipc_kmsg_max_body_space)
                return MACH_SEND_TOO_LARGE;

        if(size == sizeof(mach_msg_legacy_header_t))
                len_copied = sizeof(mach_msg_legacy_header_t);
        else
                len_copied = sizeof(mach_msg_legacy_base_t);

        if (copyinmsg(msg_addr, (char *)&legacy_base, len_copied))
                return MACH_SEND_INVALID_DATA;

        msg_addr += sizeof(legacy_base.header);
#if defined(__LP64__)
        size += LEGACY_HEADER_SIZE_DELTA;
#endif
        /* unreachable if !DEBUG */
        __unreachable_ok_push
        if (DEBUG_KPRINT_SYSCALL_PREDICATE(DEBUG_KPRINT_SYSCALL_IPC_MASK)) {
                unsigned int j;
                for (j=0; j<sizeof(legacy_base.header); j++) {
                        kprintf("%02x\n", ((unsigned char*)&legacy_base.header)[j]);
                }
        }
        __unreachable_ok_pop

        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;

        kmsg->ikm_header->msgh_size                     = size;
        kmsg->ikm_header->msgh_bits                     = legacy_base.header.msgh_bits;
        kmsg->ikm_header->msgh_remote_port      = CAST_MACH_NAME_TO_PORT(legacy_base.header.msgh_remote_port);
        kmsg->ikm_header->msgh_local_port       = CAST_MACH_NAME_TO_PORT(legacy_base.header.msgh_local_port);
        kmsg->ikm_header->msgh_voucher_port             = legacy_base.header.msgh_voucher_port;
        kmsg->ikm_header->msgh_id                       = legacy_base.header.msgh_id;

        DEBUG_KPRINT_SYSCALL_IPC("ipc_kmsg_get header:\n"
                                                         "  size:               0x%.8x\n"
                                                         "  bits:               0x%.8x\n"
                                                         "  remote_port:        %p\n"
                                                         "  local_port: %p\n"
                                                         "  voucher_port:       0x%.8x\n"
                                                         "  id:         %.8d\n",
                                                         kmsg->ikm_header->msgh_size,
                                                         kmsg->ikm_header->msgh_bits,
                                                         kmsg->ikm_header->msgh_remote_port,
                                                         kmsg->ikm_header->msgh_local_port,
                                                         kmsg->ikm_header->msgh_voucher_port,
                                                         kmsg->ikm_header->msgh_id);

        if (copyinmsg(msg_addr, (char *)(kmsg->ikm_header + 1), size - (mach_msg_size_t)sizeof(mach_msg_header_t))) {
                ipc_kmsg_free(kmsg);
                return MACH_SEND_INVALID_DATA;
        }

        /* unreachable if !DEBUG */
        __unreachable_ok_push
        if (DEBUG_KPRINT_SYSCALL_PREDICATE(DEBUG_KPRINT_SYSCALL_IPC_MASK))
        {
                kprintf("body: size: %lu\n", (size - sizeof(mach_msg_header_t)));
                uint32_t i;
                for(i=0;i*4 < (size - sizeof(mach_msg_header_t));i++)
                {
                        kprintf("%.4x\n",((uint32_t *)(kmsg->ikm_header + 1))[i]);
                }
        }
        __unreachable_ok_pop
        DEBUG_IPC_KMSG_PRINT(kmsg, "ipc_kmsg_get()");

        /* 
         * 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

        trailer->msgh_labels.sender = 0;
        *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);

        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_VALID(dest_port) && IP_PREALLOC(dest_port)) {
                mach_msg_size_t max_desc = 0;

                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 (ikm_prealloc_inuse(kmsg)) {
                        ip_unlock(dest_port);
                        return MACH_SEND_NO_BUFFER;
                }
#if !defined(__LP64__)
                if (msg->msgh_bits & MACH_MSGH_BITS_COMPLEX) {
                        assert(size > sizeof(mach_msg_base_t));
                        max_desc = ((mach_msg_base_t *)msg)->body.msgh_descriptor_count *
                                DESC_SIZE_ADJUSTMENT;
                }
#endif
                if (msg_and_trailer_size > kmsg->ikm_size - max_desc) {
                        ip_unlock(dest_port);
                        return MACH_SEND_TOO_LARGE;
                }
                ikm_prealloc_set_inuse(kmsg, dest_port);
                ikm_set_header(kmsg, msg_and_trailer_size);
                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;

        trailer->msgh_labels.sender = 0;

        *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_SEND_INVALID_DEST  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;
        thread_t th = current_thread();
        mach_msg_return_t error = MACH_MSG_SUCCESS;
        spl_t s;

        /* Check if honor qlimit flag is set on thread. */
        if ((th->options & TH_OPT_HONOR_QLIMIT) == TH_OPT_HONOR_QLIMIT) {
                /* Remove the MACH_SEND_ALWAYS flag to honor queue limit. */
                option &= (~MACH_SEND_ALWAYS);
                /* Add the timeout flag since the message queue might be full. */
                option |= MACH_SEND_TIMEOUT;
                th->options &= (~TH_OPT_HONOR_QLIMIT);
        }

#if IMPORTANCE_INHERITANCE
        boolean_t did_importance = FALSE;
#if IMPORTANCE_DEBUG
        mach_msg_id_t imp_msgh_id = -1;
        int           sender_pid  = -1;
#endif /* IMPORTANCE_DEBUG */
#endif /* IMPORTANCE_INHERITANCE */

        /* don't allow the creation of a circular loop */
        if (kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_CIRCULAR) {
                ipc_kmsg_destroy(kmsg);
                return MACH_MSG_SUCCESS;
        }

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

#if IMPORTANCE_INHERITANCE
retry:
#endif /* IMPORTANCE_INHERITANCE */
        /*
         *      Can't deliver to a dead port.
         *      However, we can pretend it got sent
         *      and was then immediately destroyed.
         */
        if (!ip_active(port)) {
                ip_unlock(port);
                ip_release(port);  /* JMM - Future: release right, not just ref */
                kmsg->ikm_header->msgh_remote_port = MACH_PORT_NULL;
                ipc_kmsg_destroy(kmsg);
                return MACH_MSG_SUCCESS;
        }

        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 */
        }

#if IMPORTANCE_INHERITANCE
        /*
         * Need to see if this message needs importance donation and/or
         * propagation.  That routine can drop the port lock temporarily.
         * If it does we'll have to revalidate the destination.
         */
        if (did_importance == FALSE) {
                did_importance = TRUE;
                if (ipc_importance_send(kmsg, option))
                        goto retry;
        }
#endif /* IMPORTANCE_INHERITANCE */

        /*
         * We have a valid message and a valid reference on the port.
         * we can unlock the port and call mqueue_send() on its message
         * queue. Lock message queue while port is locked.
         */
        s = splsched();
        imq_lock(&port->ip_messages);
        ip_unlock(port);

        error = ipc_mqueue_send(&port->ip_messages, kmsg, option, 
                        send_timeout, s);

#if IMPORTANCE_INHERITANCE
        if (did_importance == TRUE) {
                __unused int importance_cleared = 0;
                switch (error) {
                        case MACH_SEND_TIMED_OUT:
                        case MACH_SEND_NO_BUFFER:
                        case MACH_SEND_INTERRUPTED:
                        case MACH_SEND_INVALID_DEST:
                                /*
                                 * We still have the kmsg and its
                                 * reference on the port.  But we
                                 * have to back out the importance
                                 * boost.
                                 *
                                 * The port could have changed hands,
                                 * be inflight to another destination,
                                 * etc...  But in those cases our
                                 * back-out will find the new owner
                                 * (and all the operations that
                                 * transferred the right should have
                                 * applied their own boost adjustments
                                 * to the old owner(s)).
                                 */
                                importance_cleared = 1;
                                ipc_importance_clean(kmsg);
                                break;

                        case MACH_MSG_SUCCESS:
                        default:
                                break;
                }
#if IMPORTANCE_DEBUG
                KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, (IMPORTANCE_CODE(IMP_MSG, IMP_MSG_SEND)) | DBG_FUNC_END,
                                          task_pid(current_task()), sender_pid, imp_msgh_id, importance_cleared, 0);
#endif /* IMPORTANCE_DEBUG */
        }
#endif /* IMPORTANCE_INHERITANCE */

        /*
         * If the port has been destroyed while we wait, treat the message
         * as a successful delivery (like we do for an inactive port).
         */
        if (error == MACH_SEND_INVALID_DEST) {
                ip_release(port); /* JMM - Future: release right, not just ref */
                kmsg->ikm_header->msgh_remote_port = MACH_PORT_NULL;
                ipc_kmsg_destroy(kmsg);
                return MACH_MSG_SUCCESS;
        }
        return error;
}

/*
 *      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;

        DEBUG_IPC_KMSG_PRINT(kmsg, "ipc_kmsg_put()");


        DEBUG_KPRINT_SYSCALL_IPC("ipc_kmsg_put header:\n"
                                                         "  size:               0x%.8x\n"
                                                         "  bits:               0x%.8x\n"
                                                         "  remote_port:        %p\n"
                                                         "  local_port: %p\n"
                                                         "  voucher_port:       0x%.8x\n"
                                                         "  id:         %.8d\n",
                                                         kmsg->ikm_header->msgh_size,
                                                         kmsg->ikm_header->msgh_bits,
                                                         kmsg->ikm_header->msgh_remote_port,
                                                         kmsg->ikm_header->msgh_local_port,
                                                         kmsg->ikm_header->msgh_voucher_port,
                                                         kmsg->ikm_header->msgh_id);

#if defined(__LP64__)
        if (current_task() != kernel_task) { /* don't if receiver expects fully-cooked in-kernel msg; ux_exception */
                mach_msg_legacy_header_t *legacy_header = 
                        (mach_msg_legacy_header_t *)((vm_offset_t)(kmsg->ikm_header) + LEGACY_HEADER_SIZE_DELTA);

                mach_msg_bits_t         bits            = kmsg->ikm_header->msgh_bits;
                mach_msg_size_t         msg_size        = kmsg->ikm_header->msgh_size;
                mach_port_name_t        remote_port     = CAST_MACH_PORT_TO_NAME(kmsg->ikm_header->msgh_remote_port);
                mach_port_name_t        local_port      = CAST_MACH_PORT_TO_NAME(kmsg->ikm_header->msgh_local_port);
                mach_port_name_t        voucher_port    = kmsg->ikm_header->msgh_voucher_port;
                mach_msg_id_t           id                      = kmsg->ikm_header->msgh_id;

                legacy_header->msgh_id                  = id;
                legacy_header->msgh_local_port = local_port;
                legacy_header->msgh_remote_port = remote_port;
                legacy_header->msgh_voucher_port = voucher_port;
                legacy_header->msgh_size                = msg_size - LEGACY_HEADER_SIZE_DELTA;
                legacy_header->msgh_bits                = bits;

                size -= LEGACY_HEADER_SIZE_DELTA;
                kmsg->ikm_header = (mach_msg_header_t *)legacy_header;
        }
#endif

        /* unreachable if !DEBUG */
        __unreachable_ok_push
        if (DEBUG_KPRINT_SYSCALL_PREDICATE(DEBUG_KPRINT_SYSCALL_IPC_MASK)) {
                kprintf("ipc_kmsg_put header+body: %d\n", (size));
                uint32_t i;
                for(i=0;i*4 < size;i++)
                {
                        kprintf("%.4x\n",((uint32_t *)kmsg->ikm_header)[i]);
                }
                kprintf("type: %d\n", ((mach_msg_type_descriptor_t *)(((mach_msg_base_t *)kmsg->ikm_header)+1))->type);
        }
        __unreachable_ok_pop
        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.
 *
 *      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_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(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        mach_msg_option_t       *optionp)
{
        mach_msg_header_t *msg = kmsg->ikm_header;
        mach_msg_bits_t mbits = msg->msgh_bits & MACH_MSGH_BITS_USER;
        mach_port_name_t dest_name = CAST_MACH_PORT_TO_NAME(msg->msgh_remote_port);
        mach_port_name_t reply_name = CAST_MACH_PORT_TO_NAME(msg->msgh_local_port);
        mach_port_name_t voucher_name = MACH_PORT_NULL;
        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);
        mach_msg_type_name_t voucher_type = MACH_MSGH_BITS_VOUCHER(mbits);
        ipc_object_t dest_port = IO_NULL;
        ipc_object_t reply_port = IO_NULL;
        ipc_port_t dest_soright = IP_NULL;
        ipc_port_t reply_soright = IP_NULL;
        ipc_port_t voucher_soright = IP_NULL;
        ipc_port_t release_port = IP_NULL;
        ipc_port_t voucher_port = IP_NULL;
        ipc_port_t voucher_release_port = IP_NULL;
        ipc_entry_t dest_entry = IE_NULL;
        ipc_entry_t reply_entry = IE_NULL;
        ipc_entry_t voucher_entry = IE_NULL;

        int assertcnt = 0;
#if IMPORTANCE_INHERITANCE
        boolean_t needboost = FALSE;
#endif /* IMPORTANCE_INHERITANCE */

        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;

        if (!MACH_PORT_VALID(dest_name))
                return MACH_SEND_INVALID_DEST;

        is_write_lock(space);
        if (!is_active(space)) {
                is_write_unlock(space);
                return MACH_SEND_INVALID_DEST;
        }
        /* space locked and active */

        /*
         *      If there is a voucher specified, make sure the disposition is
         *      valid and the entry actually refers to a voucher port.  Don't
         *      actually copy in until we validate destination and reply.
         */
        if (voucher_type != MACH_MSGH_BITS_ZERO) {

                voucher_name = msg->msgh_voucher_port;

                if (voucher_name == MACH_PORT_DEAD ||
                    (voucher_type != MACH_MSG_TYPE_MOVE_SEND &&
                     voucher_type != MACH_MSG_TYPE_COPY_SEND)) {
                        is_write_unlock(space);
                        return MACH_SEND_INVALID_VOUCHER;
                }

                if (voucher_name != MACH_PORT_NULL) {
                        voucher_entry = ipc_entry_lookup(space, voucher_name);
                        if (voucher_entry == IE_NULL || 
                            (voucher_entry->ie_bits & MACH_PORT_TYPE_SEND) == 0 ||
                            io_kotype(voucher_entry->ie_object) != IKOT_VOUCHER) {
                                is_write_unlock(space);
                                return MACH_SEND_INVALID_VOUCHER;
                        }
                } else {
                        voucher_type = MACH_MSG_TYPE_MOVE_SEND;
                }
        }

        /*
         *      Handle combinations of validating destination and reply; along
         *      with copying in destination, reply, and voucher in an atomic way.
         */

        if (dest_name == voucher_name) {

                /*
                 *      If the destination name is the same as the voucher name,
                 *      the voucher_entry must already be known.  Either that or
                 *      the destination name is MACH_PORT_NULL (i.e. invalid).
                 */
                dest_entry = voucher_entry;
                if (dest_entry == IE_NULL) {
                        goto invalid_dest;
                }

                /*
                 *      Make sure a future copyin of the reply port will succeed.
                 *      Once we start copying in the dest/voucher pair, we can't
                 *      back out.
                 */
                if (MACH_PORT_VALID(reply_name)) {
                        assert(reply_type != 0); /* because reply_name not null */

                        /* It is just WRONG if dest, voucher, and reply are all the same. */
                        if (voucher_name == reply_name) {
                                goto invalid_reply;
                        }
                        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 */
                        if (!ipc_right_copyin_check(space, reply_name, reply_entry, reply_type)) {
                                goto invalid_reply;
                        }
                }

                /* 
                 *      Do the joint copyin of the dest disposition and 
                 *      voucher disposition from the one entry/port.  We
                 *      already validated that the voucher copyin would
                 *      succeed (above).  So, any failure in combining
                 *      the copyins can be blamed on the destination.
                 */
                kr = ipc_right_copyin_two(space, dest_name, dest_entry,
                                          dest_type, voucher_type,
                                          &dest_port, &dest_soright,
                                          &release_port);
                if (kr != KERN_SUCCESS) {
                        assert(kr != KERN_INVALID_CAPABILITY);
                        goto invalid_dest;
                }
                voucher_port = (ipc_port_t)dest_port;

                /* 
                 * could not have been one of these dispositions, 
                 * validated the port was a true kernel voucher port above,
                 * AND was successfully able to copyin both dest and voucher.
                 */
                assert(dest_type != MACH_MSG_TYPE_MAKE_SEND);
                assert(dest_type != MACH_MSG_TYPE_MAKE_SEND_ONCE);
                assert(dest_type != MACH_MSG_TYPE_MOVE_SEND_ONCE);
                
                /*
                 *      Perform the delayed reply right copyin (guaranteed success).
                 */
                if (reply_entry != IE_NULL) {
                        kr = ipc_right_copyin(space, reply_name, reply_entry,
                                              reply_type, TRUE,
                                              &reply_port, &reply_soright,
                                              &release_port, &assertcnt);
                        assert(assertcnt == 0);
                        assert(kr == KERN_SUCCESS);
                }

        } else {
                if (dest_name == reply_name) {
                        /*
                         *      Destination and reply ports are the same!
                         *      This is very similar to the case where the
                         *      destination and voucher ports were the same
                         *      (except the reply port disposition is not
                         *      previously validated).
                         */
                        dest_entry = ipc_entry_lookup(space, dest_name);
                        if (dest_entry == IE_NULL) {
                                goto invalid_dest;
                        }
                        reply_entry = dest_entry;
                        assert(reply_type != 0); /* because name not null */

                        /* 
                         *      Do the joint copyin of the dest disposition and 
                         *      reply disposition from the one entry/port.
                         */
                        kr = ipc_right_copyin_two(space, dest_name, dest_entry,
                                                  dest_type, reply_type,
                                                  &dest_port, &dest_soright,
                                                  &release_port);
                        if (kr == KERN_INVALID_CAPABILITY) {
                                goto invalid_reply;
                        } else if (kr != KERN_SUCCESS) {
                                goto invalid_dest;
                        }
                        reply_port = dest_port;


                } else {
                        /*
                         *      Handle destination and reply independently, as
                         *      they are independent entries (even if the entries
                         *      refer to the same port).
                         *
                         *      This can be the tough case to make atomic.
                         *
                         *      The difficult problem is serializing with port death.
                         *      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.
                         *      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.
                         *
                         *      Even so, avoiding that potentially detectable race is too
                         *      expensive - and no known code cares about it.  So, we just
                         *      do the expedient thing and copy them in one after the other.
                         */

                        dest_entry = ipc_entry_lookup(space, dest_name);
                        if (dest_entry == IE_NULL) {
                                goto invalid_dest;
                        }
                        assert(dest_entry != voucher_entry);

                        /*
                         *      Make sure reply port entry is valid before dest copyin.
                         */
                        if (MACH_PORT_VALID(reply_name)) {
                                if (reply_name == voucher_name) {
                                        goto invalid_reply;
                                }
                                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;
                                }
                        }

                        /*
                         *      copyin the destination.
                         */
                        kr = ipc_right_copyin(space, dest_name, dest_entry,
                                              dest_type, FALSE,
                                              &dest_port, &dest_soright,
                                              &release_port, &assertcnt);
                        assert(assertcnt == 0);
                        if (kr != KERN_SUCCESS) {
                                goto invalid_dest;
                        }
                        assert(IO_VALID(dest_port));
                        assert(!IP_VALID(release_port));

                        /*
                         *      Copyin the pre-validated reply right.
                         *      It's OK if the reply right has gone dead in the meantime.
                         */
                        if (MACH_PORT_VALID(reply_name)) {
                                kr = ipc_right_copyin(space, reply_name, reply_entry,
                                                      reply_type, TRUE,
                                                      &reply_port, &reply_soright,
                                                      &release_port, &assertcnt);
                                assert(assertcnt == 0);
                                assert(kr == KERN_SUCCESS);
                        } else {
                                /* convert invalid name to equivalent ipc_object type */
                                reply_port = (ipc_object_t)CAST_MACH_NAME_TO_PORT(reply_name);
                        }
                }

                /*
                 * Finally can copyin the voucher right now that dest and reply
                 * are fully copied in (guaranteed success).
                 */
                if (IE_NULL != voucher_entry) {
                        kr = ipc_right_copyin(space, voucher_name, voucher_entry,
                                              voucher_type, FALSE,
                                              (ipc_object_t *)&voucher_port,
                                              &voucher_soright,
                                              &voucher_release_port,
                                              &assertcnt);
                        assert(assertcnt == 0);
                        assert(KERN_SUCCESS == kr);
                        assert(IP_VALID(voucher_port));
                        assert(ip_active(voucher_port));
                }
        }

        /* the entry(s) might need to be deallocated */
        assert(IE_NULL != dest_entry);
        if (IE_BITS_TYPE(dest_entry->ie_bits) == MACH_PORT_TYPE_NONE) {
                ipc_entry_dealloc(space, dest_name, dest_entry);
                dest_entry = IE_NULL;
        }
        if (dest_entry != reply_entry && IE_NULL != reply_entry &&
            IE_BITS_TYPE(reply_entry->ie_bits) == MACH_PORT_TYPE_NONE) {
                ipc_entry_dealloc(space, reply_name, reply_entry);
                reply_entry = IE_NULL;
        }
        if (dest_entry != voucher_entry && IE_NULL != voucher_entry &&
            IE_BITS_TYPE(voucher_entry->ie_bits) == MACH_PORT_TYPE_NONE) {
                ipc_entry_dealloc(space, voucher_name, voucher_entry);
                voucher_entry = IE_NULL;
        }

        /*
         * No room to store voucher port in in-kernel msg header,
         * so we store it back in the kmsg itself.
         */
        if (IP_VALID(voucher_port)) {
                assert(ip_active(voucher_port));
                kmsg->ikm_voucher = voucher_port;
                voucher_type = MACH_MSG_TYPE_MOVE_SEND;
        }

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

        /*
         * JMM - Without rdar://problem/6275821, this is the last place we can
         * re-arm the send-possible notifications.  It may trigger unexpectedly
         * early (send may NOT have failed), but better than missing.  We assure
         * we won't miss by forcing MACH_SEND_ALWAYS if we got past arming.
         */
        if (((*optionp & MACH_SEND_NOTIFY) != 0) && 
            dest_type != MACH_MSG_TYPE_PORT_SEND_ONCE &&
            dest_entry != IE_NULL && dest_entry->ie_request != IE_REQ_NONE) {
                ipc_port_t dport = (ipc_port_t)dest_port;

                assert(dport != IP_NULL);
                ip_lock(dport);
                if (ip_active(dport) && dport->ip_receiver != ipc_space_kernel) {
                        if (ip_full(dport)) {
#if IMPORTANCE_INHERITANCE
                                needboost = ipc_port_request_sparm(dport, dest_name, 
                                                        dest_entry->ie_request,
                                                        (*optionp & MACH_SEND_NOIMPORTANCE));
                                if (needboost == FALSE)
                                        ip_unlock(dport);
#else
                                ipc_port_request_sparm(dport, dest_name, dest_entry->ie_request);
                                ip_unlock(dport);
#endif /* IMPORTANCE_INHERITANCE */
                        } else {
                                *optionp |= MACH_SEND_ALWAYS;
                                ip_unlock(dport);
                        }
                } else {
                        ip_unlock(dport);
                }
        }

        is_write_unlock(space);

#if IMPORTANCE_INHERITANCE
        /* 
         * If our request is the first boosting send-possible
         * notification this cycle, push the boost down the
         * destination port.
         */
        if (needboost == TRUE) {
                ipc_port_t dport = (ipc_port_t)dest_port;

                /* dport still locked from above */
                if (ipc_port_importance_delta(dport, 1) == FALSE) {
                        ip_unlock(dport);
                }
        }
#endif /* IMPORTANCE_INHERITANCE */

        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);
        }
        if (voucher_soright != IP_NULL) {
                ipc_notify_port_deleted(voucher_soright, voucher_name);
        }
        msg->msgh_bits = MACH_MSGH_BITS_SET(dest_type, reply_type, voucher_type, mbits);
        msg->msgh_remote_port = (ipc_port_t)dest_port;
        msg->msgh_local_port = (ipc_port_t)reply_port;

        if (release_port != IP_NULL)
                ip_release(release_port);

        if (voucher_release_port != IP_NULL)
                ip_release(voucher_release_port);

        return MACH_MSG_SUCCESS;

invalid_reply:
        is_write_unlock(space);

        if (release_port != IP_NULL)
                ip_release(release_port);

        assert(voucher_port == IP_NULL);
        assert(voucher_soright == IP_NULL);

        return MACH_SEND_INVALID_REPLY;

invalid_dest:
        is_write_unlock(space);

        if (release_port != IP_NULL)
                ip_release(release_port);

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

        assert(voucher_port == IP_NULL);
        assert(voucher_soright == IP_NULL);

        return MACH_SEND_INVALID_DEST;
}

mach_msg_descriptor_t *ipc_kmsg_copyin_port_descriptor(
        volatile mach_msg_port_descriptor_t *dsc,
        mach_msg_legacy_port_descriptor_t *user_dsc,
        ipc_space_t space,
        ipc_object_t dest,
        ipc_kmsg_t kmsg,
        mach_msg_return_t *mr);

void ipc_print_type_name(
   int type_name);
mach_msg_descriptor_t *
ipc_kmsg_copyin_port_descriptor(
        volatile mach_msg_port_descriptor_t *dsc,
        mach_msg_legacy_port_descriptor_t *user_dsc_in,
        ipc_space_t space,
        ipc_object_t dest,
        ipc_kmsg_t kmsg,
        mach_msg_return_t *mr)
{
    volatile mach_msg_legacy_port_descriptor_t *user_dsc = user_dsc_in;
    mach_msg_type_name_t        user_disp;
    mach_msg_type_name_t        result_disp;
    mach_port_name_t            name;
    ipc_object_t                        object;

    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)) {

        kern_return_t kr = ipc_object_copyin(space, name, user_disp, &object);
        if (kr != KERN_SUCCESS) {
            *mr = MACH_SEND_INVALID_RIGHT;
            return NULL;
        }

        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 = CAST_MACH_NAME_TO_PORT(name);
    }
    dsc->disposition = result_disp;
    dsc->type = MACH_MSG_PORT_DESCRIPTOR;

    dsc->pad_end = 0; // debug, unnecessary

    return (mach_msg_descriptor_t *)(user_dsc_in+1);
}

mach_msg_descriptor_t * ipc_kmsg_copyin_ool_descriptor(
        mach_msg_ool_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        int is_64bit,
        vm_offset_t *paddr,
        vm_map_copy_t *copy,
        vm_size_t *space_needed,
        vm_map_t map,
        mach_msg_return_t *mr);
mach_msg_descriptor_t *
ipc_kmsg_copyin_ool_descriptor(
        mach_msg_ool_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        int is_64bit,
        vm_offset_t *paddr,
        vm_map_copy_t *copy,
        vm_size_t *space_needed,
        vm_map_t map,
        mach_msg_return_t *mr)
{
    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;

    if (is_64bit) {
        mach_msg_ool_descriptor64_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;

        addr = (mach_vm_offset_t) user_ool_dsc->address;
        length = user_ool_dsc->size;
        dealloc = user_ool_dsc->deallocate;
        copy_options = user_ool_dsc->copy;
        dsc_type = user_ool_dsc->type;

        user_dsc = (typeof(user_dsc))(user_ool_dsc+1);
    } else {
        mach_msg_ool_descriptor32_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;

        addr = CAST_USER_ADDR_T(user_ool_dsc->address);
        dealloc = user_ool_dsc->deallocate;
        copy_options = user_ool_dsc->copy;
        dsc_type = user_ool_dsc->type;
        length = user_ool_dsc->size;

        user_dsc = (typeof(user_dsc))(user_ool_dsc+1);
    }

    dsc->size = (mach_msg_size_t)length;
    dsc->deallocate = dealloc;
    dsc->copy = copy_options;
    dsc->type = dsc_type;

    if (length == 0) {
        dsc->address = NULL;
    } 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;
            return NULL;
        }       

        /*
         * 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;
            return NULL;
        }
        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.
         */
        kern_return_t 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;
            return NULL;
        }
        dsc->address = (void *)*copy;
    }
    return user_dsc;
}

mach_msg_descriptor_t * ipc_kmsg_copyin_ool_ports_descriptor(
        mach_msg_ool_ports_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        int is_64bit,
        vm_map_t map,
        ipc_space_t space,
        ipc_object_t dest,
        ipc_kmsg_t kmsg,
        mach_msg_return_t *mr);
mach_msg_descriptor_t *
ipc_kmsg_copyin_ool_ports_descriptor(
        mach_msg_ool_ports_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        int is_64bit,
        vm_map_t map,
        ipc_space_t space,
        ipc_object_t dest,
        ipc_kmsg_t kmsg,
        mach_msg_return_t *mr)
{
    void                                        *data;
    ipc_object_t                        *objects;
    unsigned int                                i;
    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;
    mach_msg_descriptor_type_t      type;
    vm_size_t                           ports_length, names_length;

    if (is_64bit) {
        mach_msg_ool_ports_descriptor64_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;

        addr = (mach_vm_offset_t)user_ool_dsc->address;
        count = user_ool_dsc->count;
        deallocate = user_ool_dsc->deallocate;
        copy_option = user_ool_dsc->copy;
        user_disp = user_ool_dsc->disposition;
        type = user_ool_dsc->type;

        user_dsc = (typeof(user_dsc))(user_ool_dsc+1);
    } else {
        mach_msg_ool_ports_descriptor32_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;

        addr = CAST_USER_ADDR_T(user_ool_dsc->address);
        count = user_ool_dsc->count;
        deallocate = user_ool_dsc->deallocate;
        copy_option = user_ool_dsc->copy;
        user_disp = user_ool_dsc->disposition;
        type = user_ool_dsc->type;

        user_dsc = (typeof(user_dsc))(user_ool_dsc+1);
    }

    dsc->deallocate = deallocate;
    dsc->copy = copy_option;
    dsc->type = type;
    dsc->count = count;
    dsc->address = NULL;  /* for now */

    result_disp = ipc_object_copyin_type(user_disp);
    dsc->disposition = result_disp;

    if (count > (INT_MAX / sizeof(mach_port_t))) {
        *mr = MACH_SEND_TOO_LARGE;
        return NULL;
    }

    /* calculate length of data in bytes, rounding up */
    ports_length = count * sizeof(mach_port_t);
    names_length = count * sizeof(mach_port_name_t);

    if (ports_length == 0) {
        return user_dsc;
    }

    data = kalloc(ports_length);

    if (data == NULL) {
        *mr = MACH_SEND_NO_BUFFER;
        return NULL;
    }
    
#ifdef __LP64__
    mach_port_name_t *names = &((mach_port_name_t *)data)[count];
#else
    mach_port_name_t *names = ((mach_port_name_t *)data);
#endif

    if (copyinmap(map, addr, names, names_length) != KERN_SUCCESS) {
        kfree(data, ports_length);
        *mr = MACH_SEND_INVALID_MEMORY;
        return NULL;
    }

    if (deallocate) {
        (void) mach_vm_deallocate(map, addr, (mach_vm_size_t)ports_length);
    }

    objects = (ipc_object_t *) data;
    dsc->address = data;

    for ( i = 0; i < count; i++) {
        mach_port_name_t name = names[i];
        ipc_object_t object;

        if (!MACH_PORT_VALID(name)) {
            objects[i] = (ipc_object_t)CAST_MACH_NAME_TO_PORT(name);
            continue;
        }

        kern_return_t kr = ipc_object_copyin(space, name, user_disp, &object);

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

            for(j = 0; j < i; j++) {
                object = objects[j];
                if (IPC_OBJECT_VALID(object))
                    ipc_object_destroy(object, result_disp);
            }
            kfree(data, ports_length);
            dsc->address = NULL;
            *mr = MACH_SEND_INVALID_RIGHT;
            return NULL;
        }

        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[i] = object;
    }

    return user_dsc;
}

/*
 *      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
 */

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_descriptor_t       *user_addr, *kern_addr;
    mach_msg_type_number_t      dsc_count;
    boolean_t                   is_task_64bit = (map->max_offset > VM_MAX_ADDRESS);
    boolean_t                   complex = FALSE;
    vm_size_t                   space_needed = 0;
    vm_offset_t                 paddr = 0;
    vm_map_copy_t               copy = VM_MAP_COPY_NULL;
    mach_msg_type_number_t      i;
    mach_msg_return_t           mr = MACH_MSG_SUCCESS;

    vm_size_t           descriptor_size = 0;

    /*
     * 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;

    /*
     * 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 = NULL;
    for (i = 0; i < dsc_count; i++) {
        mach_msg_size_t size;

        daddr = naddr;

        /* make sure the descriptor fits in the message */
        if (is_task_64bit) {
            switch (daddr->type.type) {
            case MACH_MSG_OOL_DESCRIPTOR:
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_PORTS_DESCRIPTOR:
                    descriptor_size += 16;
            naddr = (typeof(naddr))((vm_offset_t)daddr + 16);
            break;
            default:
                    descriptor_size += 12;
            naddr = (typeof(naddr))((vm_offset_t)daddr + 12);
            break;
            }
        } else {
        descriptor_size += 12;
        naddr = (typeof(naddr))((vm_offset_t)daddr + 12);
        }

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

        switch (daddr->type.type) {
        case MACH_MSG_OOL_DESCRIPTOR:
        case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
        size = (is_task_64bit) ?
                ((mach_msg_ool_descriptor64_t *)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, NULL, 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
                 */
                if (space_needed + round_page(size) <= space_needed) {
                    /* Overflow dectected */
                    ipc_kmsg_clean_partial(kmsg, 0, NULL, 0, 0);
                    mr = MACH_MSG_VM_KERNEL;
                    goto out;
                }                   
                    
                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, NULL, 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 | VM_MAKE_TAG(VM_KERN_MEMORY_IPC)) != KERN_SUCCESS) {
            ipc_kmsg_clean_partial(kmsg, 0, NULL, 0, 0);
            mr = MACH_MSG_VM_KERNEL;
            goto out;
        }
    }

    /* user_addr = just after base as it was copied in */
    user_addr = (mach_msg_descriptor_t *)((vm_offset_t)kmsg->ikm_header + sizeof(mach_msg_base_t));

    /* Shift the mach_msg_base_t down to make room for dsc_count*16bytes of descriptors */
    if(descriptor_size != 16*dsc_count) {
        vm_offset_t dsc_adjust = 16*dsc_count - descriptor_size;

        memmove((char *)(((vm_offset_t)kmsg->ikm_header) - dsc_adjust), kmsg->ikm_header, sizeof(mach_msg_base_t));
        kmsg->ikm_header = (mach_msg_header_t *)((vm_offset_t)kmsg->ikm_header - dsc_adjust);

        /* Update the message size for the larger in-kernel representation */
        kmsg->ikm_header->msgh_size += (mach_msg_size_t)dsc_adjust;
    }


    /* kern_addr = just after base after it has been (conditionally) moved */
    kern_addr = (mach_msg_descriptor_t *)((vm_offset_t)kmsg->ikm_header + sizeof(mach_msg_base_t));

    /* handle the OOL regions and port descriptors. */
    for(i=0;i<dsc_count;i++) {
        switch (user_addr->type.type) {
            case MACH_MSG_PORT_DESCRIPTOR:
                user_addr = ipc_kmsg_copyin_port_descriptor((mach_msg_port_descriptor_t *)kern_addr, 
                        (mach_msg_legacy_port_descriptor_t *)user_addr, space, dest, kmsg, &mr);
                kern_addr++;
                complex = TRUE;
                break;
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR: 
                user_addr = ipc_kmsg_copyin_ool_descriptor((mach_msg_ool_descriptor_t *)kern_addr, 
                        user_addr, is_task_64bit, &paddr, &copy, &space_needed, map, &mr);
                kern_addr++;
                complex = TRUE;
                break;
            case MACH_MSG_OOL_PORTS_DESCRIPTOR: 
                user_addr = ipc_kmsg_copyin_ool_ports_descriptor((mach_msg_ool_ports_descriptor_t *)kern_addr, 
                        user_addr, is_task_64bit, map, space, dest, kmsg, &mr);
                kern_addr++;
                complex = TRUE;
                break;
            default:
                /* Invalid descriptor */
                mr = MACH_SEND_INVALID_TYPE;
                break;
        }

        if (MACH_MSG_SUCCESS != mr) {
            /* clean from start of message descriptors to i */
            ipc_kmsg_clean_partial(kmsg, i,
                    (mach_msg_descriptor_t *)((mach_msg_base_t *)kmsg->ikm_header + 1),
                    paddr, space_needed);
            goto out;
        }
    } /* End of loop */ 
    
    if (!complex) {
        kmsg->ikm_header->msgh_bits &= ~MACH_MSGH_BITS_COMPLEX;
    }
 out:
    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_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_msg_option_t       *optionp)
{
    mach_msg_return_t           mr;

    kmsg->ikm_header->msgh_bits &= MACH_MSGH_BITS_USER;

    mr = ipc_kmsg_copyin_header(kmsg, space, optionp);

    if (mr != MACH_MSG_SUCCESS)
        return mr;

    KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_IPC,MACH_IPC_MSG_SEND) | DBG_FUNC_NONE,
                          VM_KERNEL_ADDRPERM((uintptr_t)kmsg),
                          (uintptr_t)kmsg->ikm_header->msgh_bits,
                          (uintptr_t)kmsg->ikm_header->msgh_id,
                          VM_KERNEL_ADDRPERM((uintptr_t)unsafe_convert_port_to_voucher(kmsg->ikm_voucher)),
                          0);

    DEBUG_KPRINT_SYSCALL_IPC("ipc_kmsg_copyin header:\n%.8x\n%.8x\n%p\n%p\n%p\n%.8x\n",
                             kmsg->ikm_header->msgh_size,
                             kmsg->ikm_header->msgh_bits,
                             kmsg->ikm_header->msgh_remote_port,
                             kmsg->ikm_header->msgh_local_port,
                             kmsg->ikm_voucher,
                             kmsg->ikm_header->msgh_id);

    if ((kmsg->ikm_header->msgh_bits & MACH_MSGH_BITS_COMPLEX) == 0)
        return MACH_MSG_SUCCESS;
    
        mr = ipc_kmsg_copyin_body( kmsg, space, map);

        /* unreachable if !DEBUG */
        __unreachable_ok_push
        if (DEBUG_KPRINT_SYSCALL_PREDICATE(DEBUG_KPRINT_SYSCALL_IPC_MASK))
        {
                kprintf("body:\n");
                uint32_t i;
                for(i=0;i*4 < (kmsg->ikm_header->msgh_size - sizeof(mach_msg_header_t));i++)
                {
                        kprintf("%.4x\n",((uint32_t *)(kmsg->ikm_header + 1))[i]);
                }
        }
        __unreachable_ok_pop

        return mr;
}

/*
 *      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.
 *      Conditions:
 *              Nothing locked.
 */

mach_msg_return_t
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 */
        if (!IO_VALID(remote))
                return MACH_SEND_INVALID_DEST;

        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_SUCCESS;
        }
    {
        mach_msg_descriptor_t   *saddr;
        mach_msg_body_t         *body;
        mach_msg_type_number_t  i, count;

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

        for (i = 0; i < count; i++, 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 = (mach_msg_ool_ports_descriptor_t *)&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 */
                }
            }
        }
    }
    return MACH_MSG_SUCCESS;
}

#if IKM_SUPPORT_LEGACY
mach_msg_return_t
ipc_kmsg_copyin_from_kernel_legacy(
        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 */
        if (!IO_VALID(remote))
                return MACH_SEND_INVALID_DEST;

        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_SUCCESS;
        }
    {
        mach_msg_legacy_descriptor_t    *saddr;
        mach_msg_descriptor_t   *daddr;
        mach_msg_body_t         *body;
        mach_msg_type_number_t  i, count;

        body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
        saddr = (typeof(saddr)) (body + 1);
        count = body->msgh_descriptor_count;

    if(count) {
        vm_offset_t dsc_adjust = 4*count;
        memmove((char *)(((vm_offset_t)kmsg->ikm_header) - dsc_adjust), kmsg->ikm_header, sizeof(mach_msg_base_t));
        kmsg->ikm_header = (mach_msg_header_t *)((vm_offset_t)kmsg->ikm_header - dsc_adjust);
        /* Update the message size for the larger in-kernel representation */
        kmsg->ikm_header->msgh_size += dsc_adjust;
    }
    daddr = (mach_msg_descriptor_t *)((vm_offset_t)kmsg->ikm_header + sizeof(mach_msg_base_t));

        for (i = 0; i < count; i++, saddr++, daddr++) {
            switch (saddr->type.type) {
            
                case MACH_MSG_PORT_DESCRIPTOR: {
                    mach_msg_type_name_t        name;
                    ipc_object_t                object;
                    mach_msg_legacy_port_descriptor_t   *dsc;
                    mach_msg_port_descriptor_t  *dest_dsc;
                
                    dsc = (typeof(dsc))&saddr->port;
            dest_dsc = &daddr->port;
                
                    /* this is really the type SEND, SEND_ONCE, etc. */
                    name = dsc->disposition;
                    object = (ipc_object_t) CAST_MACH_NAME_TO_PORT(dsc->name);
                    dest_dsc->disposition = ipc_object_copyin_type(name);
            dest_dsc->name = (mach_port_t)object;
            dest_dsc->type = MACH_MSG_PORT_DESCRIPTOR;
                
                    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 ((dest_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 special. */

                    mach_msg_ool_descriptor32_t *source_dsc = &saddr->out_of_line32;
                    mach_msg_ool_descriptor_t   *dest_dsc = (typeof(dest_dsc))&daddr->out_of_line;

            vm_offset_t             address = source_dsc->address;
            vm_size_t                           size = source_dsc->size;
            boolean_t                           deallocate = source_dsc->deallocate;
            mach_msg_copy_options_t             copy = source_dsc->copy;
            mach_msg_descriptor_type_t  type = source_dsc->type;

            dest_dsc->address = (void *)address;
            dest_dsc->size = size;
            dest_dsc->deallocate = deallocate;
            dest_dsc->copy = copy;
            dest_dsc->type = type;
                    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     *dest_dsc;
                
                    mach_msg_ool_ports_descriptor32_t   *source_dsc = &saddr->ool_ports32;
            dest_dsc = (typeof(dest_dsc))&daddr->ool_ports;

            boolean_t deallocate = source_dsc->deallocate;
            mach_msg_copy_options_t copy = source_dsc->copy;
            mach_msg_size_t port_count = source_dsc->count;
            mach_msg_type_name_t disposition = source_dsc->disposition;

                    /* this is really the type SEND, SEND_ONCE, etc. */
                    name = disposition;
                    disposition = ipc_object_copyin_type(name);
                
                    objects = (ipc_object_t *) (uintptr_t)source_dsc->address;
                
                    for ( j = 0; j < port_count; j++) {
                        ipc_object_t object = objects[j];
                        
                        if (!IO_VALID(object))
                            continue;
                        
                        ipc_object_copyin_from_kernel(object, name);
    
                        if ((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;
                    }

            dest_dsc->address = objects;
            dest_dsc->deallocate = deallocate;
            dest_dsc->copy = copy;
            dest_dsc->disposition = disposition;
            dest_dsc->type = MACH_MSG_OOL_PORTS_DESCRIPTOR;
            dest_dsc->count = port_count;
                    break;
                }
                default: {
#if     MACH_ASSERT
                    panic("ipc_kmsg_copyin_from_kernel:  bad descriptor");
#endif  /* MACH_ASSERT */
                }
            }
        }
    }
    return MACH_MSG_SUCCESS;
}
#endif /* IKM_SUPPORT_LEGACY */

/*
 *      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.
 *      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(
        ipc_kmsg_t              kmsg,
        ipc_space_t             space,
        mach_msg_option_t       option)
{
        mach_msg_header_t *msg = kmsg->ikm_header;
        mach_msg_bits_t mbits = msg->msgh_bits;
        ipc_port_t dest = (ipc_port_t) msg->msgh_remote_port;

        assert(IP_VALID(dest));

        /*
         * While we still hold a reference on the received-from port,
         * process all send-possible notfications we received along with
         * the message.
         */
        ipc_port_spnotify(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);
        mach_msg_type_name_t voucher_type = MACH_MSGH_BITS_VOUCHER(mbits);
        ipc_port_t reply = msg->msgh_local_port;
        ipc_port_t release_reply_port = IP_NULL;
        mach_port_name_t dest_name, reply_name;

        ipc_port_t voucher = kmsg->ikm_voucher;
        ipc_port_t release_voucher_port = IP_NULL;
        mach_port_name_t voucher_name;

        uint32_t entries_held = 0;
        boolean_t need_write_lock = FALSE;
        kern_return_t kr;

        /*
         * Reserve any potentially needed entries in the target space.
         * We'll free any unused before unlocking the space.
         */
        if (IP_VALID(reply)) {
                entries_held++;
                need_write_lock = TRUE;
        }
        if (IP_VALID(voucher)) {
                assert(voucher_type == MACH_MSG_TYPE_MOVE_SEND); 

                if ((option & MACH_RCV_VOUCHER) != 0)
                        entries_held++;
                need_write_lock = TRUE;
        }

        if (need_write_lock) {

                is_write_lock(space);

                while(entries_held) {
                        if (!is_active(space)) {
                                is_write_unlock(space);
                                return (MACH_RCV_HEADER_ERROR|
                                        MACH_MSG_IPC_SPACE);
                        }
                                
                        kr = ipc_entries_hold(space, entries_held);
                        if (KERN_SUCCESS == kr)
                                break;

                        kr = ipc_entry_grow_table(space, ITS_SIZE_NONE);
                        if (KERN_SUCCESS != kr)
                                return(MACH_RCV_HEADER_ERROR|
                                       MACH_MSG_IPC_SPACE);
                        /* space was unlocked and relocked - retry */
                }

                /* Handle reply port. */
                if (IP_VALID(reply)) {
                        ipc_entry_t entry;

                        /* Is there already an entry we can use? */
                        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 */
                                assert(entry->ie_bits & MACH_PORT_TYPE_SEND_RECEIVE);
                        } else {
                                ip_lock(reply);
                                if (!ip_active(reply)) {
                                        ip_unlock(reply);
                                        
                                        release_reply_port = reply;
                                        reply = IP_DEAD;
                                        reply_name = MACH_PORT_DEAD;
                                        goto done_with_reply;
                                }
                                
                                /* claim a held entry for the reply port */
                                assert(entries_held > 0);
                                entries_held--;
                                ipc_entry_claim(space, &reply_name, &entry);
                                assert(IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE);
                                assert(entry->ie_object == IO_NULL); 
                                entry->ie_object = (ipc_object_t) reply;
                        }

                        /* 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);
                        assert(kr == KERN_SUCCESS);
                        /* reply port is unlocked */
                } else
                        reply_name = CAST_MACH_PORT_TO_NAME(reply);

        done_with_reply:

                /* Handle voucher port. */
                if (voucher_type != MACH_MSGH_BITS_ZERO) {
                        assert(voucher_type == MACH_MSG_TYPE_MOVE_SEND);

                        if (!IP_VALID(voucher)) {
                                if ((option & MACH_RCV_VOUCHER) == 0) {
                                        voucher_type = MACH_MSGH_BITS_ZERO;
                                }
                                voucher_name = MACH_PORT_NULL;
                                goto done_with_voucher;
                        }
                        
                        /* clear voucher from its hiding place back in the kmsg */
                        kmsg->ikm_voucher = IP_NULL;

                        if ((option & MACH_RCV_VOUCHER) != 0) {
                                ipc_entry_t entry;

                                if (ipc_right_reverse(space, (ipc_object_t) voucher,
                                                      &voucher_name, &entry)) {
                                        /* voucher port locked */
                                        assert(entry->ie_bits & MACH_PORT_TYPE_SEND);
                                } else {
                                        assert(entries_held > 0);
                                        entries_held--;
                                        ipc_entry_claim(space, &voucher_name, &entry);
                                        assert(IE_BITS_TYPE(entry->ie_bits) == MACH_PORT_TYPE_NONE);
                                        assert(entry->ie_object == IO_NULL); 
                                        entry->ie_object = (ipc_object_t) voucher;
                                        ip_lock(voucher);
                                }
                                /* space is locked and active */

                                assert(ip_active(voucher));
                                assert(ip_kotype(voucher) == IKOT_VOUCHER);
                                kr = ipc_right_copyout(space, voucher_name, entry,
                                                       MACH_MSG_TYPE_MOVE_SEND, TRUE, 
                                                       (ipc_object_t) voucher);
                                /* voucher port is unlocked */
                        } else {
                                voucher_type = MACH_MSGH_BITS_ZERO;
                                release_voucher_port = voucher;
                                voucher_name = MACH_PORT_NULL;
                        }
                } else {
                        voucher_name = msg->msgh_voucher_port;
                }

        done_with_voucher:

                ip_lock(dest);
                is_write_unlock(space);

        } else {
                /*
                 *      No reply or voucher port!  This is an easy case.
                 *      We only need to have the space locked
                 *      when locking the destination.
                 */

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

                ip_lock(dest);
                is_read_unlock(space);

                reply_name = CAST_MACH_PORT_TO_NAME(reply);

                if (voucher_type != MACH_MSGH_BITS_ZERO) {
                        assert(voucher_type == MACH_MSG_TYPE_MOVE_SEND);
                        if ((option & MACH_RCV_VOUCHER) == 0) {
                                voucher_type = MACH_MSGH_BITS_ZERO;
                        }
                        voucher_name = MACH_PORT_NULL;
                } else {
                        voucher_name = msg->msgh_voucher_port;
                }
        }

        /*
         *      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.
         */

        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_unlock(dest);
                ip_release(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))
                ip_release(reply);

        if (IP_VALID(release_reply_port)) {
                if (reply_type == MACH_MSG_TYPE_PORT_SEND_ONCE)
                        ipc_port_release_sonce(release_reply_port);
                else
                        ipc_port_release_send(release_reply_port);
        }

        if (IP_VALID(release_voucher_port))
                ipc_port_release_send(release_voucher_port);


        if ((option & MACH_RCV_VOUCHER) != 0) {
            KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_IPC, MACH_IPC_MSG_RECV) | DBG_FUNC_NONE,
                                  VM_KERNEL_ADDRPERM((uintptr_t)kmsg),
                                  (uintptr_t)kmsg->ikm_header->msgh_bits,
                                  (uintptr_t)kmsg->ikm_header->msgh_id,
                                  VM_KERNEL_ADDRPERM((uintptr_t)unsafe_convert_port_to_voucher(voucher)),
                                  0);
        } else {
            KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_IPC, MACH_IPC_MSG_RECV_VOUCHER_REFUSED) | DBG_FUNC_NONE,
                                  VM_KERNEL_ADDRPERM((uintptr_t)kmsg),
                                  (uintptr_t)kmsg->ikm_header->msgh_bits,
                                  (uintptr_t)kmsg->ikm_header->msgh_id,
                                  VM_KERNEL_ADDRPERM((uintptr_t)unsafe_convert_port_to_voucher(voucher)),
                                  0);
        }

        msg->msgh_bits = MACH_MSGH_BITS_SET(reply_type, dest_type,
                                            voucher_type, mbits);
        msg->msgh_local_port = CAST_MACH_NAME_TO_PORT(dest_name);
        msg->msgh_remote_port = CAST_MACH_NAME_TO_PORT(reply_name);
        msg->msgh_voucher_port = voucher_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 = CAST_MACH_PORT_TO_NAME(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;
}

mach_msg_descriptor_t *
ipc_kmsg_copyout_port_descriptor(mach_msg_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        ipc_space_t space,
        kern_return_t *mr);
mach_msg_descriptor_t *
ipc_kmsg_copyout_port_descriptor(mach_msg_descriptor_t *dsc,
        mach_msg_descriptor_t *dest_dsc,
        ipc_space_t space, 
        kern_return_t *mr)
{
    mach_port_t                 port;
    mach_port_name_t            name;
    mach_msg_type_name_t                disp;


    /* Copyout port right carried in the message */
    port = dsc->port.name;
    disp = dsc->port.disposition;
    *mr |= ipc_kmsg_copyout_object(space, 
            (ipc_object_t)port, 
            disp, 
            &name);

    if(current_task() == kernel_task)
    {
        mach_msg_port_descriptor_t *user_dsc = (typeof(user_dsc))dest_dsc;
        user_dsc--; // point to the start of this port descriptor
        user_dsc->name = CAST_MACH_NAME_TO_PORT(name);
        user_dsc->disposition = disp;
        user_dsc->type = MACH_MSG_PORT_DESCRIPTOR;
        dest_dsc = (typeof(dest_dsc))user_dsc;
    } else {
        mach_msg_legacy_port_descriptor_t *user_dsc = (typeof(user_dsc))dest_dsc;
        user_dsc--; // point to the start of this port descriptor
        user_dsc->name = CAST_MACH_PORT_TO_NAME(name);
        user_dsc->disposition = disp;
        user_dsc->type = MACH_MSG_PORT_DESCRIPTOR;
        dest_dsc = (typeof(dest_dsc))user_dsc;
    }

    return (mach_msg_descriptor_t *)dest_dsc;
}

mach_msg_descriptor_t *
ipc_kmsg_copyout_ool_descriptor(mach_msg_ool_descriptor_t *dsc, mach_msg_descriptor_t *user_dsc, int is_64bit, vm_map_t map, mach_msg_return_t *mr);
mach_msg_descriptor_t *
ipc_kmsg_copyout_ool_descriptor(mach_msg_ool_descriptor_t *dsc, mach_msg_descriptor_t *user_dsc, int is_64bit, vm_map_t map, mach_msg_return_t *mr)
{
    vm_map_copy_t                       copy;
    vm_map_address_t                    rcv_addr;
    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);

    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) {
        kern_return_t kr;

        rcv_addr = 0;
        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(current_task() == kernel_task)
    {
        mach_msg_ool_descriptor_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;
        user_ool_dsc--;

        user_ool_dsc->address = (void *)(uintptr_t)rcv_addr;
        user_ool_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
            TRUE : FALSE;
        user_ool_dsc->copy = copy_options;
        user_ool_dsc->type = dsc_type;
        user_ool_dsc->size = size;

        user_dsc = (typeof(user_dsc))user_ool_dsc;
    } else if (is_64bit) {
        mach_msg_ool_descriptor64_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;
        user_ool_dsc--;

        user_ool_dsc->address = rcv_addr;
        user_ool_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
            TRUE : FALSE;
        user_ool_dsc->copy = copy_options;
        user_ool_dsc->type = dsc_type;
        user_ool_dsc->size = size;

        user_dsc = (typeof(user_dsc))user_ool_dsc;
    } else {
        mach_msg_ool_descriptor32_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;
        user_ool_dsc--;

        user_ool_dsc->address = CAST_DOWN_EXPLICIT(uint32_t, rcv_addr);
        user_ool_dsc->size = size;
        user_ool_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
            TRUE : FALSE;
        user_ool_dsc->copy = copy_options;
        user_ool_dsc->type = dsc_type;

        user_dsc = (typeof(user_dsc))user_ool_dsc;
    }
    return user_dsc;
}

mach_msg_descriptor_t *
ipc_kmsg_copyout_ool_ports_descriptor(mach_msg_ool_ports_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        int is_64bit,
        vm_map_t map,
        ipc_space_t space,
        ipc_kmsg_t kmsg,
        mach_msg_return_t *mr);
mach_msg_descriptor_t *
ipc_kmsg_copyout_ool_ports_descriptor(mach_msg_ool_ports_descriptor_t *dsc,
        mach_msg_descriptor_t *user_dsc,
        int is_64bit,
        vm_map_t map,
        ipc_space_t space,
        ipc_kmsg_t kmsg,
        mach_msg_return_t *mr)
{
    mach_vm_offset_t            rcv_addr = 0;
    mach_msg_type_name_t                disp;
    mach_msg_type_number_t              count, i;
    vm_size_t                           ports_length, names_length;

    mach_msg_copy_options_t copy_options = MACH_MSG_VIRTUAL_COPY;

    //SKIP_PORT_DESCRIPTORS(saddr, sdsc_count);

    count = dsc->count;
    disp = dsc->disposition;
    ports_length = count * sizeof(mach_port_t);
    names_length = count * sizeof(mach_port_name_t);

    if (ports_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 0
        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);
        }
#endif

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

            kern_return_t kr;
            if ((kr = mach_vm_allocate(map, &rcv_addr, 
                            (mach_vm_size_t)names_length,
                            anywhere)) != KERN_SUCCESS) {
                ipc_kmsg_clean_body(kmsg, 1, (mach_msg_descriptor_t *)dsc);
                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) {
            mach_port_t *objects = (mach_port_t *) dsc->address;
            mach_port_name_t *names = (mach_port_name_t *) dsc->address;

            /* copyout port rights carried in the message */

            for ( i = 0; i < count ; i++) {
                ipc_object_t object = (ipc_object_t)objects[i];

                *mr |= ipc_kmsg_copyout_object(space, object,
                        disp, &names[i]);
            }

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

    /*
     * Now update the descriptor based on the information
     * calculated above.
     */
    if(current_task() == kernel_task) {
        mach_msg_ool_ports_descriptor_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;
        user_ool_dsc--;

        user_ool_dsc->address = (void *)(uintptr_t)rcv_addr;
        user_ool_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
            TRUE : FALSE;
        user_ool_dsc->copy = copy_options;
        user_ool_dsc->disposition = disp;
        user_ool_dsc->type = MACH_MSG_OOL_PORTS_DESCRIPTOR;
        user_ool_dsc->count = count;

        user_dsc = (typeof(user_dsc))user_ool_dsc;
    } if (is_64bit) {
        mach_msg_ool_ports_descriptor64_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;
        user_ool_dsc--;

        user_ool_dsc->address = rcv_addr;
        user_ool_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
            TRUE : FALSE;
        user_ool_dsc->copy = copy_options;
        user_ool_dsc->disposition = disp;
        user_ool_dsc->type = MACH_MSG_OOL_PORTS_DESCRIPTOR;
        user_ool_dsc->count = count;

        user_dsc = (typeof(user_dsc))user_ool_dsc;
    } else {
        mach_msg_ool_ports_descriptor32_t *user_ool_dsc = (typeof(user_ool_dsc))user_dsc;
        user_ool_dsc--;

        user_ool_dsc->address = CAST_DOWN_EXPLICIT(uint32_t, rcv_addr);
        user_ool_dsc->count = count;
        user_ool_dsc->deallocate = (copy_options == MACH_MSG_VIRTUAL_COPY) ?
            TRUE : FALSE;
        user_ool_dsc->copy = copy_options;
        user_ool_dsc->disposition = disp;
        user_ool_dsc->type = MACH_MSG_OOL_PORTS_DESCRIPTOR;

        user_dsc = (typeof(user_dsc))user_ool_dsc;
    }
    return user_dsc;
}

/*
 *      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       *kern_dsc, *user_dsc;
    mach_msg_descriptor_t       *saddr;
    mach_msg_type_number_t      dsc_count, sdsc_count;
    int i;
    mach_msg_return_t           mr = MACH_MSG_SUCCESS;
    boolean_t                   is_task_64bit = (map->max_offset > VM_MAX_ADDRESS);

    body = (mach_msg_body_t *) (kmsg->ikm_header + 1);
    dsc_count = body->msgh_descriptor_count;
    kern_dsc = (mach_msg_descriptor_t *) (body + 1);
    /* Point user_dsc just after the end of all the descriptors */
    user_dsc = &kern_dsc[dsc_count];

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

    /* Now process the descriptors */
    for (i = dsc_count-1; i >= 0; i--) {
        switch (kern_dsc[i].type.type) {

            case MACH_MSG_PORT_DESCRIPTOR: 
                user_dsc = ipc_kmsg_copyout_port_descriptor(&kern_dsc[i], user_dsc, space, &mr);
                break;
            case MACH_MSG_OOL_VOLATILE_DESCRIPTOR:
            case MACH_MSG_OOL_DESCRIPTOR : 
                user_dsc = ipc_kmsg_copyout_ool_descriptor(
                        (mach_msg_ool_descriptor_t *)&kern_dsc[i], user_dsc, is_task_64bit, map, &mr);
                break;
            case MACH_MSG_OOL_PORTS_DESCRIPTOR : 
                user_dsc = ipc_kmsg_copyout_ool_ports_descriptor(
                        (mach_msg_ool_ports_descriptor_t *)&kern_dsc[i], user_dsc, is_task_64bit, map, space, kmsg, &mr);
                break;
            default : {
                          panic("untyped IPC copyout body: invalid message descriptor");
                      }
        }
    }

    if(user_dsc != kern_dsc) {
        vm_offset_t dsc_adjust = (vm_offset_t)user_dsc - (vm_offset_t)kern_dsc;
        memmove((char *)((vm_offset_t)kmsg->ikm_header + dsc_adjust), kmsg->ikm_header, sizeof(mach_msg_base_t));
        kmsg->ikm_header = (mach_msg_header_t *)((vm_offset_t)kmsg->ikm_header + dsc_adjust);
        /* Update the message size for the smaller user representation */
        kmsg->ikm_header->msgh_size -= (mach_msg_size_t)dsc_adjust;
    }

    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;

    boolean_t is_task_64bit = (map->max_offset > VM_MAX_ADDRESS);

#if defined(__LP64__)
        send_size -= LEGACY_HEADER_SIZE_DELTA;
#endif

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

        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:
                    if(!is_task_64bit)
                        send_size -= DESC_SIZE_ADJUSTMENT;
                    break;
                case MACH_MSG_PORT_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_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_msg_body_t         *slist,
         mach_msg_option_t      option)
{
        mach_msg_return_t mr;

        mr = ipc_kmsg_copyout_header(kmsg, space, option);
        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;
        ipc_object_t voucher = (ipc_object_t) kmsg->ikm_voucher;
        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_msg_type_name_t voucher_type = MACH_MSGH_BITS_VOUCHER(mbits);
        mach_port_name_t voucher_name = kmsg->ikm_header->msgh_voucher_port;
        mach_port_name_t dest_name, reply_name;
        mach_msg_return_t mr;

        assert(IO_VALID(dest));

#if 0
        /*
         * If we did this here, it looks like we wouldn't need the undo logic
         * at the end of ipc_kmsg_send() in the error cases.  Not sure which
         * would be more elegant to keep.
         */
        ipc_importance_clean(kmsg);
#else
        /* just assert it is already clean */
        ipc_importance_assert_clean(kmsg);
#endif

        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_USER;
        kmsg->ikm_header->msgh_remote_port = CAST_MACH_NAME_TO_PORT(dest_name);
        kmsg->ikm_header->msgh_local_port = CAST_MACH_NAME_TO_PORT(reply_name);

        if (IO_VALID(voucher)) {
                assert(voucher_type == MACH_MSG_TYPE_MOVE_SEND);

                kmsg->ikm_voucher = IP_NULL;
                mr |= ipc_kmsg_copyout_object(space, voucher, voucher_type, &voucher_name);
                kmsg->ikm_header->msgh_voucher_port = voucher_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;
        ipc_object_t voucher;
        mach_msg_type_name_t dest_type;
        mach_msg_type_name_t reply_type;
        mach_msg_type_name_t voucher_type;
        mach_port_name_t dest_name, reply_name, voucher_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;
        voucher = (ipc_object_t) kmsg->ikm_voucher;
        voucher_name = kmsg->ikm_header->msgh_voucher_port;
        dest_type = MACH_MSGH_BITS_REMOTE(mbits);
        reply_type = MACH_MSGH_BITS_LOCAL(mbits);
        voucher_type = MACH_MSGH_BITS_VOUCHER(mbits);

        assert(IO_VALID(dest));

        ipc_importance_assert_clean(kmsg);

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

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

        if (IO_VALID(voucher)) {
                assert(voucher_type == MACH_MSG_TYPE_MOVE_SEND);

                kmsg->ikm_voucher = IP_NULL;
                ipc_object_destroy((ipc_object_t)voucher, voucher_type);
                voucher_name = MACH_PORT_NULL;
        }

        kmsg->ikm_header->msgh_bits = MACH_MSGH_BITS_SET(reply_type, dest_type,
                                                         voucher_type, mbits);
        kmsg->ikm_header->msgh_local_port = CAST_MACH_NAME_TO_PORT(dest_name);
        kmsg->ikm_header->msgh_remote_port = CAST_MACH_NAME_TO_PORT(reply_name);
        kmsg->ikm_header->msgh_voucher_port = voucher_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_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_unlock(dest);
                io_release(dest);
                dest_name = MACH_PORT_DEAD;
        }

        reply_name = CAST_MACH_PORT_TO_NAME(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 =  CAST_MACH_NAME_TO_PORT(dest_name);
        kmsg->ikm_header->msgh_remote_port = CAST_MACH_NAME_TO_PORT(reply_name);
}

#if IKM_SUPPORT_LEGACY
void
ipc_kmsg_copyout_to_kernel_legacy(
        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_unlock(dest);
                io_release(dest);
                dest_name = MACH_PORT_DEAD;
        }

        reply_name = CAST_MACH_PORT_TO_NAME(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 =  CAST_MACH_NAME_TO_PORT(dest_name);
        kmsg->ikm_header->msgh_remote_port = CAST_MACH_NAME_TO_PORT(reply_name);

    mach_msg_descriptor_t *saddr;
    mach_msg_legacy_descriptor_t *daddr;
    mach_msg_type_number_t i, count = ((mach_msg_base_t *)kmsg->ikm_header)->body.msgh_descriptor_count;
    saddr = (mach_msg_descriptor_t *) (((mach_msg_base_t *)kmsg->ikm_header) + 1);
    saddr = &saddr[count-1];
    daddr = (mach_msg_legacy_descriptor_t *)&saddr[count];
    daddr--;

    vm_offset_t dsc_adjust = 0;

    for (i = 0; i < count; i++, saddr--, daddr--) {
    switch (saddr->type.type) {
        case MACH_MSG_PORT_DESCRIPTOR: {
        mach_msg_port_descriptor_t *dsc = &saddr->port;
        mach_msg_legacy_port_descriptor_t *dest_dsc = &daddr->port;

        mach_port_t name = dsc->name;
        mach_msg_type_name_t disposition = dsc->disposition;

        dest_dsc->name = CAST_MACH_PORT_TO_NAME(name);
        dest_dsc->disposition = disposition;
        dest_dsc->type = MACH_MSG_PORT_DESCRIPTOR;
        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 special. */

        mach_msg_ool_descriptor_t       *source_dsc = (typeof(source_dsc))&saddr->out_of_line;

            mach_msg_ool_descriptor32_t *dest_dsc = &daddr->out_of_line32;

        vm_offset_t                         address = (vm_offset_t)source_dsc->address;
        vm_size_t                       size = source_dsc->size;
        boolean_t                       deallocate = source_dsc->deallocate;
        mach_msg_copy_options_t         copy = source_dsc->copy;
        mach_msg_descriptor_type_t  type = source_dsc->type;

        dest_dsc->address = address;
        dest_dsc->size = size;
        dest_dsc->deallocate = deallocate;
        dest_dsc->copy = copy;
        dest_dsc->type = type;
        break;
        }
    case MACH_MSG_OOL_PORTS_DESCRIPTOR: {
        mach_msg_ool_ports_descriptor_t         *source_dsc = (typeof(source_dsc))&saddr->ool_ports;

            mach_msg_ool_ports_descriptor32_t   *dest_dsc = &daddr->ool_ports32;

        vm_offset_t                         address = (vm_offset_t)source_dsc->address;
        vm_size_t                       port_count = source_dsc->count;
        boolean_t                       deallocate = source_dsc->deallocate;
        mach_msg_copy_options_t         copy = source_dsc->copy;
        mach_msg_descriptor_type_t  type = source_dsc->type;

        dest_dsc->address = address;
        dest_dsc->count = port_count;
        dest_dsc->deallocate = deallocate;
        dest_dsc->copy = copy;
        dest_dsc->type = type;
        break;
        }
        default: {
#if     MACH_ASSERT
        panic("ipc_kmsg_copyin_from_kernel:  bad descriptor");
#endif  /* MACH_ASSERT */
                 }
    }
    }

    if(count) {
        dsc_adjust = 4*count;
        memmove((char *)((vm_offset_t)kmsg->ikm_header + dsc_adjust), kmsg->ikm_header, sizeof(mach_msg_base_t));
        kmsg->ikm_header = (mach_msg_header_t *)((vm_offset_t)kmsg->ikm_header + dsc_adjust);
        /* Update the message size for the smaller user representation */
        kmsg->ikm_header->msgh_size -= dsc_adjust;
    }
}
#endif /* IKM_SUPPORT_LEGACY */


mach_msg_trailer_size_t
ipc_kmsg_add_trailer(ipc_kmsg_t kmsg, ipc_space_t space __unused, 
                mach_msg_option_t option, thread_t thread, 
                mach_port_seqno_t seqno, boolean_t minimal_trailer,
                mach_vm_offset_t context)
{
        mach_msg_max_trailer_t *trailer;

        (void)thread;
        trailer = (mach_msg_max_trailer_t *)
                ((vm_offset_t)kmsg->ikm_header +
                 round_msg(kmsg->ikm_header->msgh_size));

        if (!(option & MACH_RCV_TRAILER_MASK)) {
                return trailer->msgh_trailer_size;
        }

        trailer->msgh_seqno = seqno;
        trailer->msgh_context = context;
        trailer->msgh_trailer_size = REQUESTED_TRAILER_SIZE(thread_is_64bit(thread), option);

        if (minimal_trailer) { 
                goto done;
        }

        if (MACH_RCV_TRAILER_ELEMENTS(option) >= 
                        MACH_RCV_TRAILER_ELEMENTS(MACH_RCV_TRAILER_AV)){
                trailer->msgh_ad = 0;
        }

        /*
         * The ipc_kmsg_t holds a reference to the label of a label
         * handle, not the port. We must get a reference to the port
         * and a send right to copyout to the receiver.
         */

        if (option & MACH_RCV_TRAILER_ELEMENTS (MACH_RCV_TRAILER_LABELS)) {
                trailer->msgh_labels.sender = 0;
        }

done:

        return trailer->msgh_trailer_size;
}