osfmk/ipc/mach_msg.c

   1 /*
   2  * Copyright (c) 2000-2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56 /*
  57  * NOTICE: This file was modified by McAfee Research in 2004 to introduce
  58  * support for mandatory and extensible security protections.  This notice
  59  * is included in support of clause 2.2 (b) of the Apple Public License,
  60  * Version 2.0.
  61  * Copyright (c) 2005 SPARTA, Inc.
  62  */
  63 /*
  64  */
  65 /*
  66  *      File:   ipc/mach_msg.c
  67  *      Author: Rich Draves
  68  *      Date:   1989
  69  *
  70  *      Exported message traps.  See mach/message.h.
  71  */
  72
  73 #include <mach/mach_types.h>
  74 #include <mach/kern_return.h>
  75 #include <mach/port.h>
  76 #include <mach/message.h>
  77 #include <mach/mig_errors.h>
  78 #include <mach/mach_traps.h>
  79
  80 #include <kern/kern_types.h>
  81 #include <kern/assert.h>
  82 #include <kern/counters.h>
  83 #include <kern/cpu_number.h>
  84 #include <kern/ipc_kobject.h>
  85 #include <kern/ipc_mig.h>
  86 #include <kern/task.h>
  87 #include <kern/thread.h>
  88 #include <kern/sched_prim.h>
  89 #include <kern/exception.h>
  90 #include <kern/misc_protos.h>
  91 #include <kern/kalloc.h>
  92 #include <kern/processor.h>
  93 #include <kern/syscall_subr.h>
  94
  95 #include <vm/vm_map.h>
  96
  97 #include <ipc/ipc_types.h>
  98 #include <ipc/ipc_kmsg.h>
  99 #include <ipc/ipc_mqueue.h>
 100 #include <ipc/ipc_object.h>
 101 #include <ipc/ipc_notify.h>
 102 #include <ipc/ipc_port.h>
 103 #include <ipc/ipc_pset.h>
 104 #include <ipc/ipc_space.h>
 105 #include <ipc/ipc_entry.h>
 106 #include <ipc/ipc_importance.h>
 107
 108 #include <machine/machine_routines.h>
 109 #include <security/mac_mach_internal.h>
 110
 111 #include <sys/kdebug.h>
 112
 113 #ifndef offsetof
 114 #define offsetof(type, member)  ((size_t)(&((type *)0)->member))
 115 #endif /* offsetof */
 116
 117 /*
 118  * Forward declarations - kernel internal routines
 119  */
 120
 121 mach_msg_return_t mach_msg_send(
 122         mach_msg_header_t       *msg,
 123         mach_msg_option_t       option,
 124         mach_msg_size_t         send_size,
 125         mach_msg_timeout_t      send_timeout,
 126         mach_port_name_t        notify);
 127
 128 mach_msg_return_t mach_msg_receive(
 129         mach_msg_header_t       *msg,
 130         mach_msg_option_t       option,
 131         mach_msg_size_t         rcv_size,
 132         mach_port_name_t        rcv_name,
 133         mach_msg_timeout_t      rcv_timeout,
 134         void                    (*continuation)(mach_msg_return_t),
 135         mach_msg_size_t         slist_size);
 136
 137
 138 mach_msg_return_t msg_receive_error(
 139         ipc_kmsg_t              kmsg,
 140         mach_vm_address_t       msg_addr,
 141         mach_msg_option_t       option,
 142         mach_port_seqno_t       seqno,
 143         ipc_space_t             space);
 144
 145 security_token_t KERNEL_SECURITY_TOKEN = KERNEL_SECURITY_TOKEN_VALUE;
 146 audit_token_t KERNEL_AUDIT_TOKEN = KERNEL_AUDIT_TOKEN_VALUE;
 147
 148 mach_msg_format_0_trailer_t trailer_template = {
 149         /* mach_msg_trailer_type_t */ MACH_MSG_TRAILER_FORMAT_0,
 150         /* mach_msg_trailer_size_t */ MACH_MSG_TRAILER_MINIMUM_SIZE,
 151         /* mach_port_seqno_t */       0,
 152         /* security_token_t */        KERNEL_SECURITY_TOKEN_VALUE
 153 };
 154
 155 /*
 156  *      Routine:        mach_msg_send [Kernel Internal]
 157  *      Purpose:
 158  *              Routine for kernel-task threads to send a message.
 159  *
 160  *              Unlike mach_msg_send_from_kernel(), this routine
 161  *              looks port names up in the kernel's port namespace
 162  *              and copies in the kernel virtual memory (instead
 163  *              of taking a vm_map_copy_t pointer for OOL descriptors).
 164  *      Conditions:
 165  *              Nothing locked.
 166  *      Returns:
 167  *              MACH_MSG_SUCCESS        Sent the message.
 168  *              MACH_SEND_MSG_TOO_SMALL Message smaller than a header.
 169  *              MACH_SEND_NO_BUFFER     Couldn't allocate buffer.
 170  *              MACH_SEND_INVALID_DATA  Couldn't copy message data.
 171  *              MACH_SEND_INVALID_HEADER
 172  *                      Illegal value in the message header bits.
 173  *              MACH_SEND_INVALID_DEST  The space is dead.
 174  *              MACH_SEND_INVALID_NOTIFY        Bad notify port.
 175  *              MACH_SEND_INVALID_DEST  Can't copyin destination port.
 176  *              MACH_SEND_INVALID_REPLY Can't copyin reply port.
 177  *              MACH_SEND_TIMED_OUT     Timeout expired without delivery.
 178  *              MACH_SEND_INTERRUPTED   Delivery interrupted.
 179  */
 180
 181 mach_msg_return_t
 182 mach_msg_send(
 183         mach_msg_header_t       *msg,
 184         mach_msg_option_t       option,
 185         mach_msg_size_t         send_size,
 186         mach_msg_timeout_t      send_timeout,
 187         __unused mach_port_name_t       notify)
 188 {
 189         ipc_space_t space = current_space();
 190         vm_map_t map = current_map();
 191         ipc_kmsg_t kmsg;
 192         mach_msg_return_t mr;
 193         mach_msg_size_t msg_and_trailer_size;
 194         mach_msg_max_trailer_t  *trailer;
 195
 196         if ((send_size < sizeof(mach_msg_header_t)) || (send_size & 3))
 197                 return MACH_SEND_MSG_TOO_SMALL;
 198
 199         if (send_size > MACH_MSG_SIZE_MAX - MAX_TRAILER_SIZE)
 200                 return MACH_SEND_TOO_LARGE;
 201
 202         msg_and_trailer_size = send_size + MAX_TRAILER_SIZE;
 203
 204         kmsg = ipc_kmsg_alloc(msg_and_trailer_size);
 205
 206         if (kmsg == IKM_NULL)
 207                 return MACH_SEND_NO_BUFFER;
 208
 209         (void) memcpy((void *) kmsg->ikm_header, (const void *) msg, send_size);
 210
 211         kmsg->ikm_header->msgh_size = send_size;
 212
 213         /*
 214          * reserve for the trailer the largest space (MAX_TRAILER_SIZE)
 215          * However, the internal size field of the trailer (msgh_trailer_size)
 216          * is initialized to the minimum (sizeof(mach_msg_trailer_t)), to optimize
 217          * the cases where no implicit data is requested.
 218          */
 219         trailer = (mach_msg_max_trailer_t *) ((vm_offset_t)kmsg->ikm_header + send_size);
 220         trailer->msgh_sender = current_thread()->task->sec_token;
 221         trailer->msgh_audit = current_thread()->task->audit_token;
 222         trailer->msgh_trailer_type = MACH_MSG_TRAILER_FORMAT_0;
 223         trailer->msgh_trailer_size = MACH_MSG_TRAILER_MINIMUM_SIZE;
 224
 225         mr = ipc_kmsg_copyin(kmsg, space, map, &option);
 226
 227         if (mr != MACH_MSG_SUCCESS) {
 228                 ipc_kmsg_free(kmsg);
 229                 return mr;
 230         }
 231
 232         mr = ipc_kmsg_send(kmsg, option, send_timeout);
 233
 234         if (mr != MACH_MSG_SUCCESS) {
 235             mr |= ipc_kmsg_copyout_pseudo(kmsg, space, map, MACH_MSG_BODY_NULL);
 236             (void) memcpy((void *) msg, (const void *) kmsg->ikm_header,
 237                           kmsg->ikm_header->msgh_size);
 238             ipc_kmsg_free(kmsg);
 239         }
 240
 241         return mr;
 242 }
 243
 244 /*
 245  * message header as seen at user-space
 246  * (for MACH_RCV_LARGE/IDENTITY updating)
 247  */
 248 typedef struct
 249 {
 250   mach_msg_bits_t       msgh_bits;
 251   mach_msg_size_t       msgh_size;
 252   mach_port_name_t      msgh_remote_port;
 253   mach_port_name_t      msgh_local_port;
 254   mach_msg_size_t       msgh_reserved;
 255   mach_msg_id_t         msgh_id;
 256 } mach_msg_user_header_t;
 257
 258 /*
 259  *      Routine:        mach_msg_receive_results
 260  *      Purpose:
 261  *              Receive a message.
 262  *      Conditions:
 263  *              Nothing locked.
 264  *      Returns:
 265  *              MACH_MSG_SUCCESS        Received a message.
 266  *              MACH_RCV_INVALID_NAME   The name doesn't denote a right,
 267  *                      or the denoted right is not receive or port set.
 268  *              MACH_RCV_IN_SET         Receive right is a member of a set.
 269  *              MACH_RCV_TOO_LARGE      Message wouldn't fit into buffer.
 270  *              MACH_RCV_TIMED_OUT      Timeout expired without a message.
 271  *              MACH_RCV_INTERRUPTED    Reception interrupted.
 272  *              MACH_RCV_PORT_DIED      Port/set died while receiving.
 273  *              MACH_RCV_PORT_CHANGED   Port moved into set while receiving.
 274  *              MACH_RCV_INVALID_DATA   Couldn't copy to user buffer.
 275  *              MACH_RCV_INVALID_NOTIFY Bad notify port.
 276  *              MACH_RCV_HEADER_ERROR
 277  */
 278
 279 mach_msg_return_t
 280 mach_msg_receive_results(void)
 281 {
 282         thread_t          self = current_thread();
 283         ipc_space_t       space = current_space();
 284         vm_map_t          map = current_map();
 285
 286         ipc_object_t      object = self->ith_object;
 287         mach_msg_return_t mr = self->ith_state;
 288         mach_vm_address_t msg_addr = self->ith_msg_addr;
 289         mach_msg_option_t option = self->ith_option;
 290         ipc_kmsg_t        kmsg = self->ith_kmsg;
 291         mach_port_seqno_t seqno = self->ith_seqno;
 292         mach_msg_trailer_size_t trailer_size;
 293
 294         io_release(object);
 295
 296         if (mr != MACH_MSG_SUCCESS) {
 297
 298           if (mr == MACH_RCV_TOO_LARGE ) {
 299             if (option & MACH_RCV_LARGE) {
 300               /*
 301                * We need to inform the user-level code that it needs more
 302                * space.  The value for how much space was returned in the
 303                * msize save area instead of the message (which was left on
 304                * the queue).
 305                */
 306               if (option & MACH_RCV_LARGE_IDENTITY) {
 307                       if (copyout((char *) &self->ith_receiver_name,
 308                                   msg_addr + offsetof(mach_msg_user_header_t, msgh_local_port),
 309                                   sizeof(mach_port_name_t)))
 310                               mr = MACH_RCV_INVALID_DATA;
 311               }
 312               if (copyout((char *) &self->ith_msize,
 313                           msg_addr + offsetof(mach_msg_user_header_t, msgh_size),
 314                           sizeof(mach_msg_size_t)))
 315                 mr = MACH_RCV_INVALID_DATA;
 316             } else {
 317
 318                 /* discard importance in message */
 319                 ipc_importance_clean(kmsg);
 320
 321                 if (msg_receive_error(kmsg, msg_addr, option, seqno, space)
 322                     == MACH_RCV_INVALID_DATA)
 323                     mr = MACH_RCV_INVALID_DATA;
 324             }
 325           }
 326           return mr;
 327         }
 328
 329 #if IMPORTANCE_INHERITANCE
 330
 331         /* adopt/transform any importance attributes carried in the message */
 332         ipc_importance_receive(kmsg, option);
 333
 334 #endif  /* IMPORTANCE_INHERITANCE */
 335
 336         trailer_size = ipc_kmsg_add_trailer(kmsg, space, option, self, seqno, FALSE,
 337                         kmsg->ikm_header->msgh_remote_port->ip_context);
 338         /*
 339          * If MACH_RCV_OVERWRITE was specified, try to get the scatter
 340          * list and verify it against the contents of the message.  If
 341          * there is any problem with it, we will continue without it as
 342          * normal.
 343          */
 344         if (option & MACH_RCV_OVERWRITE) {
 345                 mach_msg_size_t slist_size = self->ith_scatter_list_size;
 346                 mach_msg_body_t *slist;
 347
 348                 slist = ipc_kmsg_get_scatter(msg_addr, slist_size, kmsg);
 349                 mr = ipc_kmsg_copyout(kmsg, space, map, slist, option);
 350                 ipc_kmsg_free_scatter(slist, slist_size);
 351         } else {
 352                 mr = ipc_kmsg_copyout(kmsg, space, map, MACH_MSG_BODY_NULL, option);
 353         }
 354
 355         if (mr != MACH_MSG_SUCCESS) {
 356                 /* already received importance, so have to undo that here */
 357                 ipc_importance_unreceive(kmsg, option);
 358
 359                 if ((mr &~ MACH_MSG_MASK) == MACH_RCV_BODY_ERROR) {
 360                         if (ipc_kmsg_put(msg_addr, kmsg, kmsg->ikm_header->msgh_size +
 361                            trailer_size) == MACH_RCV_INVALID_DATA)
 362                                 mr = MACH_RCV_INVALID_DATA;
 363                 }
 364                 else {
 365                         if (msg_receive_error(kmsg, msg_addr, option, seqno, space)
 366                                                 == MACH_RCV_INVALID_DATA)
 367                                 mr = MACH_RCV_INVALID_DATA;
 368                 }
 369         } else {
 370                 mr = ipc_kmsg_put(msg_addr,
 371                                   kmsg,
 372                                   kmsg->ikm_header->msgh_size +
 373                                   trailer_size);
 374         }
 375
 376         return mr;
 377 }
 378
 379 /*
 380  *      Routine:        mach_msg_receive [Kernel Internal]
 381  *      Purpose:
 382  *              Routine for kernel-task threads to actively receive a message.
 383  *
 384  *              Unlike being dispatched to by ipc_kobject_server() or the
 385  *              reply part of mach_msg_rpc_from_kernel(), this routine
 386  *              looks up the receive port name in the kernel's port
 387  *              namespace and copies out received port rights to that namespace
 388  *              as well.  Out-of-line memory is copied out the kernel's
 389  *              address space (rather than just providing the vm_map_copy_t).
 390  *      Conditions:
 391  *              Nothing locked.
 392  *      Returns:
 393  *              MACH_MSG_SUCCESS        Received a message.
 394  *              See <mach/message.h> for list of MACH_RCV_XXX errors.
 395  */
 396 mach_msg_return_t
 397 mach_msg_receive(
 398         mach_msg_header_t       *msg,
 399         mach_msg_option_t       option,
 400         mach_msg_size_t         rcv_size,
 401         mach_port_name_t        rcv_name,
 402         mach_msg_timeout_t      rcv_timeout,
 403         void                    (*continuation)(mach_msg_return_t),
 404         mach_msg_size_t         slist_size)
 405 {
 406         thread_t self = current_thread();
 407         ipc_space_t space = current_space();
 408         ipc_object_t object;
 409         ipc_mqueue_t mqueue;
 410         mach_msg_return_t mr;
 411
 412         mr = ipc_mqueue_copyin(space, rcv_name, &mqueue, &object);
 413         if (mr != MACH_MSG_SUCCESS) {
 414                 return mr;
 415         }
 416         /* hold ref for object */
 417
 418         self->ith_msg_addr = CAST_DOWN(mach_vm_address_t, msg);
 419         self->ith_object = object;
 420         self->ith_msize = rcv_size;
 421         self->ith_option = option;
 422         self->ith_scatter_list_size = slist_size;
 423         self->ith_continuation = continuation;
 424
 425         ipc_mqueue_receive(mqueue, option, rcv_size, rcv_timeout, THREAD_ABORTSAFE);
 426         if ((option & MACH_RCV_TIMEOUT) && rcv_timeout == 0)
 427                 thread_poll_yield(self);
 428         return mach_msg_receive_results();
 429 }
 430
 431 void
 432 mach_msg_receive_continue(void)
 433 {
 434         thread_t self = current_thread();
 435
 436         (*self->ith_continuation)(mach_msg_receive_results());
 437 }
 438
 439
 440 /*
 441  *      Routine:        mach_msg_overwrite_trap [mach trap]
 442  *      Purpose:
 443  *              Possibly send a message; possibly receive a message.
 444  *      Conditions:
 445  *              Nothing locked.
 446  *      Returns:
 447  *              All of mach_msg_send and mach_msg_receive error codes.
 448  */
 449
 450 mach_msg_return_t
 451 mach_msg_overwrite_trap(
 452         struct mach_msg_overwrite_trap_args *args)
 453 {
 454         mach_vm_address_t       msg_addr = args->msg;
 455         mach_msg_option_t       option = args->option;
 456         mach_msg_size_t         send_size = args->send_size;
 457         mach_msg_size_t         rcv_size = args->rcv_size;
 458         mach_port_name_t        rcv_name = args->rcv_name;
 459         mach_msg_timeout_t      msg_timeout = args->timeout;
 460         __unused mach_port_name_t notify = args->notify;
 461         mach_vm_address_t       rcv_msg_addr = args->rcv_msg;
 462         mach_msg_size_t         scatter_list_size = 0; /* NOT INITIALIZED - but not used in pactice */
 463         __unused mach_port_seqno_t temp_seqno = 0;
 464
 465         mach_msg_return_t  mr = MACH_MSG_SUCCESS;
 466         vm_map_t map = current_map();
 467
 468         /* Only accept options allowed by the user */
 469         option &= MACH_MSG_OPTION_USER;
 470
 471         if (option & MACH_SEND_MSG) {
 472                 ipc_space_t space = current_space();
 473                 ipc_kmsg_t kmsg;
 474
 475                 mr = ipc_kmsg_get(msg_addr, send_size, &kmsg);
 476
 477                 if (mr != MACH_MSG_SUCCESS)
 478                         return mr;
 479
 480                 mr = ipc_kmsg_copyin(kmsg, space, map, &option);
 481
 482                 if (mr != MACH_MSG_SUCCESS) {
 483                         ipc_kmsg_free(kmsg);
 484                         return mr;
 485                 }
 486
 487                 mr = ipc_kmsg_send(kmsg, option, msg_timeout);
 488
 489                 if (mr != MACH_MSG_SUCCESS) {
 490                         mr |= ipc_kmsg_copyout_pseudo(kmsg, space, map, MACH_MSG_BODY_NULL);
 491                         (void) ipc_kmsg_put(msg_addr, kmsg, kmsg->ikm_header->msgh_size);
 492                         return mr;
 493                 }
 494
 495         }
 496
 497         if (option & MACH_RCV_MSG) {
 498                 thread_t self = current_thread();
 499                 ipc_space_t space = current_space();
 500                 ipc_object_t object;
 501                 ipc_mqueue_t mqueue;
 502
 503                 mr = ipc_mqueue_copyin(space, rcv_name, &mqueue, &object);
 504                 if (mr != MACH_MSG_SUCCESS) {
 505                         return mr;
 506                 }
 507                 /* hold ref for object */
 508
 509                 /*
 510                  * 1. MACH_RCV_OVERWRITE is on, and rcv_msg is our scatter list
 511                  *    and receive buffer
 512                  * 2. MACH_RCV_OVERWRITE is off, and rcv_msg might be the
 513                  *    alternate receive buffer (separate send and receive buffers).
 514                  */
 515                 if (option & MACH_RCV_OVERWRITE)
 516                         self->ith_msg_addr = rcv_msg_addr;
 517                 else if (rcv_msg_addr != (mach_vm_address_t)0)
 518                         self->ith_msg_addr = rcv_msg_addr;
 519                 else
 520                         self->ith_msg_addr = msg_addr;
 521                 self->ith_object = object;
 522                 self->ith_msize = rcv_size;
 523                 self->ith_option = option;
 524                 self->ith_scatter_list_size = scatter_list_size;
 525                 self->ith_receiver_name = MACH_PORT_NULL;
 526                 self->ith_continuation = thread_syscall_return;
 527
 528                 ipc_mqueue_receive(mqueue, option, rcv_size, msg_timeout, THREAD_ABORTSAFE);
 529                 if ((option & MACH_RCV_TIMEOUT) && msg_timeout == 0)
 530                         thread_poll_yield(self);
 531                 return mach_msg_receive_results();
 532         }
 533
 534         return MACH_MSG_SUCCESS;
 535 }
 536
 537 /*
 538  *      Routine:        mach_msg_trap [mach trap]
 539  *      Purpose:
 540  *              Possibly send a message; possibly receive a message.
 541  *      Conditions:
 542  *              Nothing locked.
 543  *      Returns:
 544  *              All of mach_msg_send and mach_msg_receive error codes.
 545  */
 546
 547 mach_msg_return_t
 548 mach_msg_trap(
 549         struct mach_msg_overwrite_trap_args *args)
 550 {
 551         kern_return_t kr;
 552         args->rcv_msg = (mach_vm_address_t)0;
 553
 554         kr = mach_msg_overwrite_trap(args);
 555         return kr;
 556 }
 557
 558
 559 /*
 560  *      Routine:        msg_receive_error       [internal]
 561  *      Purpose:
 562  *              Builds a minimal header/trailer and copies it to
 563  *              the user message buffer.  Invoked when in the case of a
 564  *              MACH_RCV_TOO_LARGE or MACH_RCV_BODY_ERROR error.
 565  *      Conditions:
 566  *              Nothing locked.
 567  *      Returns:
 568  *              MACH_MSG_SUCCESS        minimal header/trailer copied
 569  *              MACH_RCV_INVALID_DATA   copyout to user buffer failed
 570  */
 571
 572 mach_msg_return_t
 573 msg_receive_error(
 574         ipc_kmsg_t              kmsg,
 575         mach_vm_address_t       msg_addr,
 576         mach_msg_option_t       option,
 577         mach_port_seqno_t       seqno,
 578         ipc_space_t             space)
 579 {
 580         mach_vm_address_t       context;
 581         mach_msg_trailer_size_t trailer_size;
 582         mach_msg_max_trailer_t  *trailer;
 583
 584         context = kmsg->ikm_header->msgh_remote_port->ip_context;
 585
 586         /*
 587          * Copy out the destination port in the message.
 588          * Destroy all other rights and memory in the message.
 589          */
 590         ipc_kmsg_copyout_dest(kmsg, space);
 591
 592         /*
 593          * Build a minimal message with the requested trailer.
 594          */
 595         trailer = (mach_msg_max_trailer_t *)
 596                         ((vm_offset_t)kmsg->ikm_header +
 597                         round_msg(sizeof(mach_msg_header_t)));
 598         kmsg->ikm_header->msgh_size = sizeof(mach_msg_header_t);
 599         bcopy(  (char *)&trailer_template,
 600                 (char *)trailer,
 601                 sizeof(trailer_template));
 602
 603         trailer_size = ipc_kmsg_add_trailer(kmsg, space,
 604                         option, current_thread(), seqno,
 605                         TRUE, context);
 606
 607         /*
 608          * Copy the message to user space
 609          */
 610         if (ipc_kmsg_put(msg_addr, kmsg, kmsg->ikm_header->msgh_size +
 611                         trailer_size) == MACH_RCV_INVALID_DATA)
 612                 return(MACH_RCV_INVALID_DATA);
 613         else
 614                 return(MACH_MSG_SUCCESS);
 615 }