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 1.3  1995/01/21 15:00:57  roland
  53  * Converted to use weak aliases with macros from libc-symbols.h.
  54  *
  55  * Revision 1.2  1994/10/10  07:20:14  roland
  56  * Increase default MAX_SIZE to two pages.
  57  *
  58  * Revision 1.1  1993/12/06  23:25:25  roland
  59  * entered into RCS
  60  *
  61  * Revision 2.4  91/05/14  17:53:22  mrt
  62  *      Correcting copyright
  63  *
  64  * Revision 2.3  91/02/14  14:17:47  mrt
  65  *      Added new Mach copyright
  66  *      [91/02/13  12:44:20  mrt]
  67  *
  68  * Revision 2.2  90/08/06  17:23:58  rpd
  69  *      Created.
  70  *
  71  */
  72
  73
  74 #include <mach.h>
  75 #include <mach/mig_errors.h>
  76 #include <stdlib.h>             /* For malloc and free.  */
  77
  78 mach_msg_return_t
  79 __mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
  80                                                mach_msg_header_t *reply),
  81                            mach_msg_size_t max_size,
  82                            mach_port_t rcv_name,
  83                            mach_msg_option_t option,
  84                            mach_msg_timeout_t timeout)
  85 {
  86   register mig_reply_header_t *request, *reply;
  87   register mach_msg_return_t mr;
  88
  89   if (max_size == 0)
  90     {
  91       option |= MACH_RCV_LARGE;
  92       max_size = 2 * __vm_page_size; /* Generic.  Good? XXX */
  93     }
  94
  95   request = __alloca (max_size);
  96   reply = __alloca (max_size);
  97
  98   while (1)
  99     {
 100     get_request:
 101       mr = __mach_msg (&request->Head, MACH_RCV_MSG|option,
 102                        0, max_size, rcv_name,
 103                        timeout, MACH_PORT_NULL);
 104       while (mr == MACH_MSG_SUCCESS)
 105         {
 106           /* We have a request message.
 107              Pass it to DEMUX for processing.  */
 108
 109           (void) (*demux) (&request->Head, &reply->Head);
 110
 111           switch (reply->RetCode)
 112             {
 113             case KERN_SUCCESS:
 114               /* Hunky dory.  */
 115               break;
 116
 117             case MIG_NO_REPLY:
 118               /* The server function wanted no reply sent.
 119                  Loop for another request.  */
 120               goto get_request;
 121
 122             default:
 123               /* Some error; destroy the request message to release any
 124                  port rights or VM it holds.  Don't destroy the reply port
 125                  right, so we can send an error message.  */
 126               request->Head.msgh_remote_port = MACH_PORT_NULL;
 127               __mach_msg_destroy (&request->Head);
 128               break;
 129             }
 130
 131           if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
 132             {
 133               /* No reply port, so destroy the reply.  */
 134               if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
 135                 __mach_msg_destroy (&reply->Head);
 136               goto get_request;
 137             }
 138
 139           /* Send the reply and the get next request.  */
 140
 141           {
 142             /* Swap the request and reply buffers.  mach_msg will read the
 143                reply message from the buffer we pass and write the new
 144                request message to the same buffer.  */
 145             void *tmp = request;
 146             request = reply;
 147             reply = tmp;
 148           }
 149
 150           mr = __mach_msg (&request->Head,
 151                            MACH_SEND_MSG|MACH_RCV_MSG|option,
 152                            request->Head.msgh_size, max_size, rcv_name,
 153                            timeout, MACH_PORT_NULL);
 154         }
 155
 156       /* A message error occurred.  */
 157
 158       switch (mr)
 159         {
 160         case MACH_RCV_TOO_LARGE:
 161           /* The request message is larger than MAX_SIZE, and has not
 162              been dequued.  The message header has the actual size of
 163              the message.  We recurse here in hopes that the compiler
 164              will optimize the tail-call and allocate some more stack
 165              space instead of way too much.  */
 166           return __mach_msg_server_timeout (demux, request->Head.msgh_size,
 167                                             rcv_name, option, timeout);
 168
 169         case MACH_SEND_INVALID_DEST:
 170           /* The reply can't be delivered, so destroy it.  This error
 171              indicates only that the requestor went away, so we
 172              continue and get the next request.  */
 173           __mach_msg_destroy (&request->Head);
 174           break;
 175
 176         default:
 177           /* Some other form of lossage; return to caller.  */
 178           return mr;
 179         }
 180     }
 181 }
 182 weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)
 183
 184 mach_msg_return_t
 185 __mach_msg_server (demux, max_size, rcv_name)
 186      boolean_t (*demux) ();
 187      mach_msg_size_t max_size;
 188      mach_port_t rcv_name;
 189 {
 190   return __mach_msg_server_timeout (demux, max_size, rcv_name,
 191                                     MACH_MSG_OPTION_NONE,
 192                                     MACH_MSG_TIMEOUT_NONE);
 193 }
 194 weak_alias (__mach_msg_server, mach_msg_server)