summary refs log tree commit diff
path: root/mach/msgserver.c
blob: d95e545985adf759aeb457f152ca0f756adfe596 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
/* Copyright (C) 1993-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

/* Based on CMU's mach_msg_server.c revision 2.4 of 91/05/14, and thus
   under the following copyright.  Rewritten by Roland McGrath (FSF)
   93/12/06 to use stack space instead of malloc, and to handle
   large messages with MACH_RCV_LARGE.  */

/*
 * Mach Operating System
 * Copyright (c) 1991,1990 Carnegie Mellon University
 * All Rights Reserved.
 *
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 *
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 *
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 * (pre-GNU) HISTORY
 *
 * Revision 2.4  91/05/14  17:53:22  mrt
 * 	Correcting copyright
 *
 * Revision 2.3  91/02/14  14:17:47  mrt
 * 	Added new Mach copyright
 * 	[91/02/13  12:44:20  mrt]
 *
 * Revision 2.2  90/08/06  17:23:58  rpd
 * 	Created.
 *
 */


#include <mach.h>
#include <mach/mig_errors.h>
#include <stdlib.h>		/* For malloc and free.  */
#include <assert.h>

#ifdef NDR_CHAR_ASCII		/* OSF Mach flavors have different names.  */
# define mig_reply_header_t	mig_reply_error_t
#endif

mach_msg_return_t
__mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
					       mach_msg_header_t *reply),
			   mach_msg_size_t max_size,
			   mach_port_t rcv_name,
			   mach_msg_option_t option,
			   mach_msg_timeout_t timeout)
{
  mig_reply_header_t *request, *reply;
  mach_msg_return_t mr;

  if (max_size == 0)
    {
#ifdef MACH_RCV_LARGE
      option |= MACH_RCV_LARGE;
      max_size = 2 * __vm_page_size; /* Generic.  Good? XXX */
#else
      max_size = 4 * __vm_page_size; /* XXX */
#endif
    }

  request = __alloca (max_size);
  reply = __alloca (max_size);

  while (1)
    {
    get_request:
      mr = __mach_msg (&request->Head, MACH_RCV_MSG|option,
		       0, max_size, rcv_name,
		       timeout, MACH_PORT_NULL);
      while (mr == MACH_MSG_SUCCESS)
	{
	  /* We have a request message.
	     Pass it to DEMUX for processing.  */

	  (void) (*demux) (&request->Head, &reply->Head);
	  assert (reply->Head.msgh_size <= max_size);

	  switch (reply->RetCode)
	    {
	    case KERN_SUCCESS:
	      /* Hunky dory.  */
	      break;

	    case MIG_NO_REPLY:
	      /* The server function wanted no reply sent.
		 Loop for another request.  */
	      goto get_request;

	    default:
	      /* Some error; destroy the request message to release any
		 port rights or VM it holds.  Don't destroy the reply port
		 right, so we can send an error message.  */
	      request->Head.msgh_remote_port = MACH_PORT_NULL;
	      __mach_msg_destroy (&request->Head);
	      break;
	    }

	  if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
	    {
	      /* No reply port, so destroy the reply.  */
	      if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
		__mach_msg_destroy (&reply->Head);
	      goto get_request;
	    }

	  /* Send the reply and the get next request.  */

	  {
	    /* Swap the request and reply buffers.  mach_msg will read the
	       reply message from the buffer we pass and write the new
	       request message to the same buffer.  */
	    void *tmp = request;
	    request = reply;
	    reply = tmp;
	  }

	  mr = __mach_msg (&request->Head,
			   MACH_SEND_MSG|MACH_RCV_MSG|option,
			   request->Head.msgh_size, max_size, rcv_name,
			   timeout, MACH_PORT_NULL);
	}

      /* A message error occurred.  */

      switch (mr)
	{
	case MACH_RCV_TOO_LARGE:
#ifdef MACH_RCV_LARGE
	  /* The request message is larger than MAX_SIZE, and has not
	     been dequeued.  The message header has the actual size of
	     the message.  We recurse here in hopes that the compiler
	     will optimize the tail-call and allocate some more stack
	     space instead of way too much.  */
	  return __mach_msg_server_timeout (demux, request->Head.msgh_size,
					    rcv_name, option, timeout);
#else
	  /* XXX the kernel has destroyed the msg */
	  break;
#endif

	case MACH_SEND_INVALID_DEST:
	  /* The reply can't be delivered, so destroy it.  This error
	     indicates only that the requester went away, so we
	     continue and get the next request.  */
	  __mach_msg_destroy (&request->Head);
	  break;

	default:
	  /* Some other form of lossage; return to caller.  */
	  return mr;
	}
    }
}
weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)

mach_msg_return_t
__mach_msg_server (boolean_t (*demux) (mach_msg_header_t *in,
				       mach_msg_header_t *out),
		   mach_msg_size_t max_size,
		   mach_port_t rcv_name)
{
  return __mach_msg_server_timeout (demux, max_size, rcv_name,
				    MACH_MSG_OPTION_NONE,
				    MACH_MSG_TIMEOUT_NONE);
}
weak_alias (__mach_msg_server, mach_msg_server)