mach/msgserver.c

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