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  * (pre-GNU) HISTORY
  51  *
  52  * Revision 2.4  91/05/14  17:53:22  mrt
  53  *      Correcting copyright
  54  *
  55  * Revision 2.3  91/02/14  14:17:47  mrt
  56  *      Added new Mach copyright
  57  *      [91/02/13  12:44:20  mrt]
  58  *
  59  * Revision 2.2  90/08/06  17:23:58  rpd
  60  *      Created.
  61  *
  62  */
  63
  64
  65 #include <mach.h>
  66 #include <mach/mig_errors.h>
  67 #include <stdlib.h>             /* For malloc and free.  */
  68 #include <assert.h>
  69
  70 #ifdef NDR_CHAR_ASCII           /* OSF Mach flavors have different names.  */
  71 # define mig_reply_header_t     mig_reply_error_t
  72 #endif
  73
  74 mach_msg_return_t
  75 __mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
  76                                                mach_msg_header_t *reply),
  77                            mach_msg_size_t max_size,
  78                            mach_port_t rcv_name,
  79                            mach_msg_option_t option,
  80                            mach_msg_timeout_t timeout)
  81 {
  82   register mig_reply_header_t *request, *reply;
  83   register mach_msg_return_t mr;
  84
  85   if (max_size == 0)
  86     {
  87 #ifdef MACH_RCV_LARGE
  88       option |= MACH_RCV_LARGE;
  89       max_size = 2 * __vm_page_size; /* Generic.  Good? XXX */
  90 #else
  91       max_size = 4 * __vm_page_size; /* XXX */
  92 #endif
  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           assert (reply->Head.msgh_size <= max_size);
 111
 112           switch (reply->RetCode)
 113             {
 114             case KERN_SUCCESS:
 115               /* Hunky dory.  */
 116               break;
 117
 118             case MIG_NO_REPLY:
 119               /* The server function wanted no reply sent.
 120                  Loop for another request.  */
 121               goto get_request;
 122
 123             default:
 124               /* Some error; destroy the request message to release any
 125                  port rights or VM it holds.  Don't destroy the reply port
 126                  right, so we can send an error message.  */
 127               request->Head.msgh_remote_port = MACH_PORT_NULL;
 128               __mach_msg_destroy (&request->Head);
 129               break;
 130             }
 131
 132           if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
 133             {
 134               /* No reply port, so destroy the reply.  */
 135               if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
 136                 __mach_msg_destroy (&reply->Head);
 137               goto get_request;
 138             }
 139
 140           /* Send the reply and the get next request.  */
 141
 142           {
 143             /* Swap the request and reply buffers.  mach_msg will read the
 144                reply message from the buffer we pass and write the new
 145                request message to the same buffer.  */
 146             void *tmp = request;
 147             request = reply;
 148             reply = tmp;
 149           }
 150
 151           mr = __mach_msg (&request->Head,
 152                            MACH_SEND_MSG|MACH_RCV_MSG|option,
 153                            request->Head.msgh_size, max_size, rcv_name,
 154                            timeout, MACH_PORT_NULL);
 155         }
 156
 157       /* A message error occurred.  */
 158
 159       switch (mr)
 160         {
 161         case MACH_RCV_TOO_LARGE:
 162 #ifdef MACH_RCV_LARGE
 163           /* The request message is larger than MAX_SIZE, and has not
 164              been dequeued.  The message header has the actual size of
 165              the message.  We recurse here in hopes that the compiler
 166              will optimize the tail-call and allocate some more stack
 167              space instead of way too much.  */
 168           return __mach_msg_server_timeout (demux, request->Head.msgh_size,
 169                                             rcv_name, option, timeout);
 170 #else
 171           /* XXX the kernel has destroyed the msg */
 172           break;
 173 #endif
 174
 175         case MACH_SEND_INVALID_DEST:
 176           /* The reply can't be delivered, so destroy it.  This error
 177              indicates only that the requester went away, so we
 178              continue and get the next request.  */
 179           __mach_msg_destroy (&request->Head);
 180           break;
 181
 182         default:
 183           /* Some other form of lossage; return to caller.  */
 184           return mr;
 185         }
 186     }
 187 }
 188 weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)
 189
 190 mach_msg_return_t
 191 __mach_msg_server (demux, max_size, rcv_name)
 192      boolean_t (*demux) (mach_msg_header_t *in, mach_msg_header_t *out);
 193      mach_msg_size_t max_size;
 194      mach_port_t rcv_name;
 195 {
 196   return __mach_msg_server_timeout (demux, max_size, rcv_name,
 197                                     MACH_MSG_OPTION_NONE,
 198                                     MACH_MSG_TIMEOUT_NONE);
 199 }
 200 weak_alias (__mach_msg_server, mach_msg_server)