mach/msgserver.c

   1 /* Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 /* Based on CMU's mach_msg_server.c revision 2.4 of 91/05/14, and thus
  20    under the following copyright.  Rewritten by Roland McGrath (FSF)
  21    93/12/06 to use stack space instead of malloc, and to handle
  22    large messages with MACH_RCV_LARGE.  */
  23
  24 /*
  25  * Mach Operating System
  26  * Copyright (c) 1991,1990 Carnegie Mellon University
  27  * All Rights Reserved.
  28  *
  29  * Permission to use, copy, modify and distribute this software and its
  30  * documentation is hereby granted, provided that both the copyright
  31  * notice and this permission notice appear in all copies of the
  32  * software, derivative works or modified versions, and any portions
  33  * thereof, and that both notices appear in supporting documentation.
  34  *
  35  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  36  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  37  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  38  *
  39  * Carnegie Mellon requests users of this software to return to
  40  *
  41  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  42  *  School of Computer Science
  43  *  Carnegie Mellon University
  44  *  Pittsburgh PA 15213-3890
  45  *
  46  * any improvements or extensions that they make and grant Carnegie Mellon
  47  * the rights to redistribute these changes.
  48  */
  49 /*
  50  * HISTORY
  51  * $Log$
  52  * Revision 1.4  1996/01/29 15:44:23  roland
  53  * Declare DEMUX arg with prototype.
  54  *
  55  * Revision 1.3  1995/01/21  15:00:57  roland
  56  * Converted to use weak aliases with macros from libc-symbols.h.
  57  *
  58  * Revision 1.2  1994/10/10  07:20:14  roland
  59  * Increase default MAX_SIZE to two pages.
  60  *
  61  * Revision 1.1  1993/12/06  23:25:25  roland
  62  * entered into RCS
  63  *
  64  * Revision 2.4  91/05/14  17:53:22  mrt
  65  *      Correcting copyright
  66  *
  67  * Revision 2.3  91/02/14  14:17:47  mrt
  68  *      Added new Mach copyright
  69  *      [91/02/13  12:44:20  mrt]
  70  *
  71  * Revision 2.2  90/08/06  17:23:58  rpd
  72  *      Created.
  73  *
  74  */
  75
  76
  77 #include <mach.h>
  78 #include <mach/mig_errors.h>
  79 #include <stdlib.h>             /* For malloc and free.  */
  80
  81 mach_msg_return_t
  82 __mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
  83                                                mach_msg_header_t *reply),
  84                            mach_msg_size_t max_size,
  85                            mach_port_t rcv_name,
  86                            mach_msg_option_t option,
  87                            mach_msg_timeout_t timeout)
  88 {
  89   register mig_reply_header_t *request, *reply;
  90   register mach_msg_return_t mr;
  91
  92   if (max_size == 0)
  93     {
  94       option |= MACH_RCV_LARGE;
  95       max_size = 2 * __vm_page_size; /* Generic.  Good? XXX */
  96     }
  97
  98   request = __alloca (max_size);
  99   reply = __alloca (max_size);
 100
 101   while (1)
 102     {
 103     get_request:
 104       mr = __mach_msg (&request->Head, MACH_RCV_MSG|option,
 105                        0, max_size, rcv_name,
 106                        timeout, MACH_PORT_NULL);
 107       while (mr == MACH_MSG_SUCCESS)
 108         {
 109           /* We have a request message.
 110              Pass it to DEMUX for processing.  */
 111
 112           (void) (*demux) (&request->Head, &reply->Head);
 113
 114           switch (reply->RetCode)
 115             {
 116             case KERN_SUCCESS:
 117               /* Hunky dory.  */
 118               break;
 119
 120             case MIG_NO_REPLY:
 121               /* The server function wanted no reply sent.
 122                  Loop for another request.  */
 123               goto get_request;
 124
 125             default:
 126               /* Some error; destroy the request message to release any
 127                  port rights or VM it holds.  Don't destroy the reply port
 128                  right, so we can send an error message.  */
 129               request->Head.msgh_remote_port = MACH_PORT_NULL;
 130               __mach_msg_destroy (&request->Head);
 131               break;
 132             }
 133
 134           if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
 135             {
 136               /* No reply port, so destroy the reply.  */
 137               if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
 138                 __mach_msg_destroy (&reply->Head);
 139               goto get_request;
 140             }
 141
 142           /* Send the reply and the get next request.  */
 143
 144           {
 145             /* Swap the request and reply buffers.  mach_msg will read the
 146                reply message from the buffer we pass and write the new
 147                request message to the same buffer.  */
 148             void *tmp = request;
 149             request = reply;
 150             reply = tmp;
 151           }
 152
 153           mr = __mach_msg (&request->Head,
 154                            MACH_SEND_MSG|MACH_RCV_MSG|option,
 155                            request->Head.msgh_size, max_size, rcv_name,
 156                            timeout, MACH_PORT_NULL);
 157         }
 158
 159       /* A message error occurred.  */
 160
 161       switch (mr)
 162         {
 163         case MACH_RCV_TOO_LARGE:
 164           /* The request message is larger than MAX_SIZE, and has not
 165              been dequued.  The message header has the actual size of
 166              the message.  We recurse here in hopes that the compiler
 167              will optimize the tail-call and allocate some more stack
 168              space instead of way too much.  */
 169           return __mach_msg_server_timeout (demux, request->Head.msgh_size,
 170                                             rcv_name, option, timeout);
 171
 172         case MACH_SEND_INVALID_DEST:
 173           /* The reply can't be delivered, so destroy it.  This error
 174              indicates only that the requestor went away, so we
 175              continue and get the next request.  */
 176           __mach_msg_destroy (&request->Head);
 177           break;
 178
 179         default:
 180           /* Some other form of lossage; return to caller.  */
 181           return mr;
 182         }
 183     }
 184 }
 185 weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)
 186
 187 mach_msg_return_t
 188 __mach_msg_server (demux, max_size, rcv_name)
 189      boolean_t (*demux) (mach_msg_header_t *in, mach_msg_header_t *out);
 190      mach_msg_size_t max_size;
 191      mach_port_t rcv_name;
 192 {
 193   return __mach_msg_server_timeout (demux, max_size, rcv_name,
 194                                     MACH_MSG_OPTION_NONE,
 195                                     MACH_MSG_TIMEOUT_NONE);
 196 }
 197 weak_alias (__mach_msg_server, mach_msg_server)