mach/msgserver.c

   1 /* Copyright (C) 1993, 1994, 1995, 1996, 2001 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 not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, 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 1.6  2001/04/09 21:23:38  roland
  53  * 2001-04-07  Roland McGrath  <roland@frob.com>
  54  *
  55  *      * mach/msgserver.c (__mach_msg_server_timeout): Add an assert.
  56  *
  57  * Revision 1.5  1996/12/20 01:32:35  drepper
  58  * Update from main archive 961219
  59  *
  60  * Revision 1.5  1996/12/19 20:23:45  drepper
  61  * Spelling corrections.
  62  *
  63  * Revision 1.4  1996/01/29 15:44:23  roland
  64  * Declare DEMUX arg with prototype.
  65  *
  66  * Revision 1.3  1995/01/21  15:00:57  roland
  67  * Converted to use weak aliases with macros from libc-symbols.h.
  68  *
  69  * Revision 1.2  1994/10/10  07:20:14  roland
  70  * Increase default MAX_SIZE to two pages.
  71  *
  72  * Revision 1.1  1993/12/06  23:25:25  roland
  73  * entered into RCS
  74  *
  75  * Revision 2.4  91/05/14  17:53:22  mrt
  76  *      Correcting copyright
  77  *
  78  * Revision 2.3  91/02/14  14:17:47  mrt
  79  *      Added new Mach copyright
  80  *      [91/02/13  12:44:20  mrt]
  81  *
  82  * Revision 2.2  90/08/06  17:23:58  rpd
  83  *      Created.
  84  *
  85  */
  86
  87
  88 #include <mach.h>
  89 #include <mach/mig_errors.h>
  90 #include <stdlib.h>             /* For malloc and free.  */
  91 #include <assert.h>
  92
  93 mach_msg_return_t
  94 __mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
  95                                                mach_msg_header_t *reply),
  96                            mach_msg_size_t max_size,
  97                            mach_port_t rcv_name,
  98                            mach_msg_option_t option,
  99                            mach_msg_timeout_t timeout)
 100 {
 101   register mig_reply_header_t *request, *reply;
 102   register mach_msg_return_t mr;
 103
 104   if (max_size == 0)
 105     {
 106       option |= MACH_RCV_LARGE;
 107       max_size = 2 * __vm_page_size; /* Generic.  Good? XXX */
 108     }
 109
 110   request = __alloca (max_size);
 111   reply = __alloca (max_size);
 112
 113   while (1)
 114     {
 115     get_request:
 116       mr = __mach_msg (&request->Head, MACH_RCV_MSG|option,
 117                        0, max_size, rcv_name,
 118                        timeout, MACH_PORT_NULL);
 119       while (mr == MACH_MSG_SUCCESS)
 120         {
 121           /* We have a request message.
 122              Pass it to DEMUX for processing.  */
 123
 124           (void) (*demux) (&request->Head, &reply->Head);
 125           assert (reply->Head.msgh_size <= max_size);
 126
 127           switch (reply->RetCode)
 128             {
 129             case KERN_SUCCESS:
 130               /* Hunky dory.  */
 131               break;
 132
 133             case MIG_NO_REPLY:
 134               /* The server function wanted no reply sent.
 135                  Loop for another request.  */
 136               goto get_request;
 137
 138             default:
 139               /* Some error; destroy the request message to release any
 140                  port rights or VM it holds.  Don't destroy the reply port
 141                  right, so we can send an error message.  */
 142               request->Head.msgh_remote_port = MACH_PORT_NULL;
 143               __mach_msg_destroy (&request->Head);
 144               break;
 145             }
 146
 147           if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
 148             {
 149               /* No reply port, so destroy the reply.  */
 150               if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
 151                 __mach_msg_destroy (&reply->Head);
 152               goto get_request;
 153             }
 154
 155           /* Send the reply and the get next request.  */
 156
 157           {
 158             /* Swap the request and reply buffers.  mach_msg will read the
 159                reply message from the buffer we pass and write the new
 160                request message to the same buffer.  */
 161             void *tmp = request;
 162             request = reply;
 163             reply = tmp;
 164           }
 165
 166           mr = __mach_msg (&request->Head,
 167                            MACH_SEND_MSG|MACH_RCV_MSG|option,
 168                            request->Head.msgh_size, max_size, rcv_name,
 169                            timeout, MACH_PORT_NULL);
 170         }
 171
 172       /* A message error occurred.  */
 173
 174       switch (mr)
 175         {
 176         case MACH_RCV_TOO_LARGE:
 177           /* The request message is larger than MAX_SIZE, and has not
 178              been dequeued.  The message header has the actual size of
 179              the message.  We recurse here in hopes that the compiler
 180              will optimize the tail-call and allocate some more stack
 181              space instead of way too much.  */
 182           return __mach_msg_server_timeout (demux, request->Head.msgh_size,
 183                                             rcv_name, option, timeout);
 184
 185         case MACH_SEND_INVALID_DEST:
 186           /* The reply can't be delivered, so destroy it.  This error
 187              indicates only that the requester went away, so we
 188              continue and get the next request.  */
 189           __mach_msg_destroy (&request->Head);
 190           break;
 191
 192         default:
 193           /* Some other form of lossage; return to caller.  */
 194           return mr;
 195         }
 196     }
 197 }
 198 weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)
 199
 200 mach_msg_return_t
 201 __mach_msg_server (demux, max_size, rcv_name)
 202      boolean_t (*demux) (mach_msg_header_t *in, mach_msg_header_t *out);
 203      mach_msg_size_t max_size;
 204      mach_port_t rcv_name;
 205 {
 206   return __mach_msg_server_timeout (demux, max_size, rcv_name,
 207                                     MACH_MSG_OPTION_NONE,
 208                                     MACH_MSG_TIMEOUT_NONE);
 209 }
 210 weak_alias (__mach_msg_server, mach_msg_server)