mach/msgserver.c

   1 /* Copyright (C) 1993,94,95,96,2001,02 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    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 1.9  2002/02/18 20:56:35  roland
  53  * 2002-02-18  Roland McGrath  <roland@frob.com>
  54  *
  55  *      * mach/msgserver.c (__mach_msg_server_timeout) [! MACH_RCV_LARGE]:
  56  *      Double MAX_SIZE and don't retry on MACH_RCV_TOO_LARGE.
  57  *
  58  * Revision 1.8  2002/02/17 07:13:32  roland
  59  * 2002-02-16  Roland McGrath  <roland@frob.com>
  60  *
  61  *      * mach/msgserver.c [NDR_CHAR_ASCII] (mig_reply_header_t): #define as
  62  *      mig_reply_error_t for OSF Mach variant.
  63  *
  64  * Revision 1.7  2001/07/06 04:55:34  aj
  65  * Update to LGPL v2.1.
  66  *
  67  * Revision 1.6  2001/04/09 21:23:38  roland
  68  * 2001-04-07  Roland McGrath  <roland@frob.com>
  69  *
  70  *      * mach/msgserver.c (__mach_msg_server_timeout): Add an assert.
  71  *
  72  * Revision 1.5  1996/12/20 01:32:35  drepper
  73  * Update from main archive 961219
  74  *
  75  * Revision 1.5  1996/12/19 20:23:45  drepper
  76  * Spelling corrections.
  77  *
  78  * Revision 1.4  1996/01/29 15:44:23  roland
  79  * Declare DEMUX arg with prototype.
  80  *
  81  * Revision 1.3  1995/01/21  15:00:57  roland
  82  * Converted to use weak aliases with macros from libc-symbols.h.
  83  *
  84  * Revision 1.2  1994/10/10  07:20:14  roland
  85  * Increase default MAX_SIZE to two pages.
  86  *
  87  * Revision 1.1  1993/12/06  23:25:25  roland
  88  * entered into RCS
  89  *
  90  * Revision 2.4  91/05/14  17:53:22  mrt
  91  *      Correcting copyright
  92  *
  93  * Revision 2.3  91/02/14  14:17:47  mrt
  94  *      Added new Mach copyright
  95  *      [91/02/13  12:44:20  mrt]
  96  *
  97  * Revision 2.2  90/08/06  17:23:58  rpd
  98  *      Created.
  99  *
 100  */
 101
 102
 103 #include <mach.h>
 104 #include <mach/mig_errors.h>
 105 #include <stdlib.h>             /* For malloc and free.  */
 106 #include <assert.h>
 107
 108 #ifdef NDR_CHAR_ASCII           /* OSF Mach flavors have different names.  */
 109 # define mig_reply_header_t     mig_reply_error_t
 110 #endif
 111
 112 mach_msg_return_t
 113 __mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
 114                                                mach_msg_header_t *reply),
 115                            mach_msg_size_t max_size,
 116                            mach_port_t rcv_name,
 117                            mach_msg_option_t option,
 118                            mach_msg_timeout_t timeout)
 119 {
 120   register mig_reply_header_t *request, *reply;
 121   register mach_msg_return_t mr;
 122
 123   if (max_size == 0)
 124     {
 125 #ifdef MACH_RCV_LARGE
 126       option |= MACH_RCV_LARGE;
 127       max_size = 2 * __vm_page_size; /* Generic.  Good? XXX */
 128 #else
 129       max_size = 4 * __vm_page_size; /* XXX */
 130 #endif
 131     }
 132
 133   request = __alloca (max_size);
 134   reply = __alloca (max_size);
 135
 136   while (1)
 137     {
 138     get_request:
 139       mr = __mach_msg (&request->Head, MACH_RCV_MSG|option,
 140                        0, max_size, rcv_name,
 141                        timeout, MACH_PORT_NULL);
 142       while (mr == MACH_MSG_SUCCESS)
 143         {
 144           /* We have a request message.
 145              Pass it to DEMUX for processing.  */
 146
 147           (void) (*demux) (&request->Head, &reply->Head);
 148           assert (reply->Head.msgh_size <= max_size);
 149
 150           switch (reply->RetCode)
 151             {
 152             case KERN_SUCCESS:
 153               /* Hunky dory.  */
 154               break;
 155
 156             case MIG_NO_REPLY:
 157               /* The server function wanted no reply sent.
 158                  Loop for another request.  */
 159               goto get_request;
 160
 161             default:
 162               /* Some error; destroy the request message to release any
 163                  port rights or VM it holds.  Don't destroy the reply port
 164                  right, so we can send an error message.  */
 165               request->Head.msgh_remote_port = MACH_PORT_NULL;
 166               __mach_msg_destroy (&request->Head);
 167               break;
 168             }
 169
 170           if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
 171             {
 172               /* No reply port, so destroy the reply.  */
 173               if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
 174                 __mach_msg_destroy (&reply->Head);
 175               goto get_request;
 176             }
 177
 178           /* Send the reply and the get next request.  */
 179
 180           {
 181             /* Swap the request and reply buffers.  mach_msg will read the
 182                reply message from the buffer we pass and write the new
 183                request message to the same buffer.  */
 184             void *tmp = request;
 185             request = reply;
 186             reply = tmp;
 187           }
 188
 189           mr = __mach_msg (&request->Head,
 190                            MACH_SEND_MSG|MACH_RCV_MSG|option,
 191                            request->Head.msgh_size, max_size, rcv_name,
 192                            timeout, MACH_PORT_NULL);
 193         }
 194
 195       /* A message error occurred.  */
 196
 197       switch (mr)
 198         {
 199         case MACH_RCV_TOO_LARGE:
 200 #ifdef MACH_RCV_LARGE
 201           /* The request message is larger than MAX_SIZE, and has not
 202              been dequeued.  The message header has the actual size of
 203              the message.  We recurse here in hopes that the compiler
 204              will optimize the tail-call and allocate some more stack
 205              space instead of way too much.  */
 206           return __mach_msg_server_timeout (demux, request->Head.msgh_size,
 207                                             rcv_name, option, timeout);
 208 #else
 209           /* XXX the kernel has destroyed the msg */
 210           break;
 211 #endif
 212
 213         case MACH_SEND_INVALID_DEST:
 214           /* The reply can't be delivered, so destroy it.  This error
 215              indicates only that the requester went away, so we
 216              continue and get the next request.  */
 217           __mach_msg_destroy (&request->Head);
 218           break;
 219
 220         default:
 221           /* Some other form of lossage; return to caller.  */
 222           return mr;
 223         }
 224     }
 225 }
 226 weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)
 227
 228 mach_msg_return_t
 229 __mach_msg_server (demux, max_size, rcv_name)
 230      boolean_t (*demux) (mach_msg_header_t *in, mach_msg_header_t *out);
 231      mach_msg_size_t max_size;
 232      mach_port_t rcv_name;
 233 {
 234   return __mach_msg_server_timeout (demux, max_size, rcv_name,
 235                                     MACH_MSG_OPTION_NONE,
 236                                     MACH_MSG_TIMEOUT_NONE);
 237 }
 238 weak_alias (__mach_msg_server, mach_msg_server)