1 /* Copyright (C) 1993-2023 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, see
16 <https://www.gnu.org/licenses/>. */
17
18 /* Based on CMU's mach_msg_server.c revision 2.4 of 91/05/14, and thus
19 under the following copyright. Rewritten by Roland McGrath (FSF)
20 93/12/06 to use stack space instead of malloc, and to handle
21 large messages with MACH_RCV_LARGE. */
22
23 /*
24 * Mach Operating System
25 * Copyright (c) 1991,1990 Carnegie Mellon University
26 * All Rights Reserved.
27 *
28 * Permission to use, copy, modify and distribute this software and its
29 * documentation is hereby granted, provided that both the copyright
30 * notice and this permission notice appear in all copies of the
31 * software, derivative works or modified versions, and any portions
32 * thereof, and that both notices appear in supporting documentation.
33 *
34 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
35 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
36 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
37 *
38 * Carnegie Mellon requests users of this software to return to
39 *
40 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
41 * School of Computer Science
42 * Carnegie Mellon University
43 * Pittsburgh PA 15213-3890
44 *
45 * any improvements or extensions that they make and grant Carnegie Mellon
46 * the rights to redistribute these changes.
47 */
48 /*
49 * (pre-GNU) HISTORY
50 *
51 * Revision 2.4 91/05/14 17:53:22 mrt
52 * Correcting copyright
53 *
54 * Revision 2.3 91/02/14 14:17:47 mrt
55 * Added new Mach copyright
56 * [91/02/13 12:44:20 mrt]
57 *
58 * Revision 2.2 90/08/06 17:23:58 rpd
59 * Created.
60 *
61 */
62
63
64 #include <mach.h>
65 #include <mach/mig_errors.h>
66 #include <stdlib.h> /* For malloc and free. */
67 #include <assert.h>
68
69 #ifdef NDR_CHAR_ASCII /* OSF Mach flavors have different names. */
70 # define mig_reply_header_t mig_reply_error_t
71 #endif
72
73 mach_msg_return_t
74 __mach_msg_server_timeout (boolean_t (*demux) (mach_msg_header_t *request,
75 mach_msg_header_t *reply),
76 mach_msg_size_t max_size,
77 mach_port_t rcv_name,
78 mach_msg_option_t option,
79 mach_msg_timeout_t timeout)
80 {
81 mig_reply_header_t *request, *reply;
82 mach_msg_return_t mr;
83
84 if (max_size == 0)
85 {
86 #ifdef MACH_RCV_LARGE
87 option |= MACH_RCV_LARGE;
88 max_size = 2 * __vm_page_size; /* Generic. Good? XXX */
89 #else
90 max_size = 4 * __vm_page_size; /* XXX */
91 #endif
92 }
93
94 request = __alloca (max_size);
95 reply = __alloca (max_size);
96
97 while (1)
98 {
99 get_request:
100 mr = __mach_msg (&request->Head, MACH_RCV_MSG|option,
101 0, max_size, rcv_name,
102 timeout, MACH_PORT_NULL);
103 while (mr == MACH_MSG_SUCCESS)
104 {
105 /* We have a request message.
106 Pass it to DEMUX for processing. */
107
108 (void) (*demux) (&request->Head, &reply->Head);
109 assert (reply->Head.msgh_size <= max_size);
110
111 switch (reply->RetCode)
112 {
113 case KERN_SUCCESS:
114 /* Hunky dory. */
115 break;
116
117 case MIG_NO_REPLY:
118 /* The server function wanted no reply sent.
119 Loop for another request. */
120 goto get_request;
121
122 default:
123 /* Some error; destroy the request message to release any
124 port rights or VM it holds. Don't destroy the reply port
125 right, so we can send an error message. */
126 request->Head.msgh_remote_port = MACH_PORT_NULL;
127 __mach_msg_destroy (&request->Head);
128 break;
129 }
130
131 if (reply->Head.msgh_remote_port == MACH_PORT_NULL)
132 {
133 /* No reply port, so destroy the reply. */
134 if (reply->Head.msgh_bits & MACH_MSGH_BITS_COMPLEX)
135 __mach_msg_destroy (&reply->Head);
136 goto get_request;
137 }
138
139 /* Send the reply and the get next request. */
140
141 {
142 /* Swap the request and reply buffers. mach_msg will read the
143 reply message from the buffer we pass and write the new
144 request message to the same buffer. */
145 void *tmp = request;
146 request = reply;
147 reply = tmp;
148 }
149
150 mr = __mach_msg (&request->Head,
151 MACH_SEND_MSG|MACH_RCV_MSG|option,
152 request->Head.msgh_size, max_size, rcv_name,
153 timeout, MACH_PORT_NULL);
154 }
155
156 /* A message error occurred. */
157
158 switch (mr)
159 {
160 case MACH_RCV_TOO_LARGE:
161 #ifdef MACH_RCV_LARGE
162 /* The request message is larger than MAX_SIZE, and has not
163 been dequeued. The message header has the actual size of
164 the message. We recurse here in hopes that the compiler
165 will optimize the tail-call and allocate some more stack
166 space instead of way too much. */
167 return __mach_msg_server_timeout (demux, request->Head.msgh_size,
168 rcv_name, option, timeout);
169 #else
170 /* XXX the kernel has destroyed the msg */
171 break;
172 #endif
173
174 case MACH_SEND_INVALID_DEST:
175 /* The reply can't be delivered, so destroy it. This error
176 indicates only that the requester went away, so we
177 continue and get the next request. */
178 __mach_msg_destroy (&request->Head);
179 break;
180
181 default:
182 /* Some other form of lossage; return to caller. */
183 return mr;
184 }
185 }
186 }
187 weak_alias (__mach_msg_server_timeout, mach_msg_server_timeout)
188
189 mach_msg_return_t
190 __mach_msg_server (boolean_t (*demux) (mach_msg_header_t *in,
191 mach_msg_header_t *out),
192 mach_msg_size_t max_size,
193 mach_port_t rcv_name)
194 {
195 return __mach_msg_server_timeout (demux, max_size, rcv_name,
196 MACH_MSG_OPTION_NONE,
197 MACH_MSG_TIMEOUT_NONE);
198 }
199 weak_alias (__mach_msg_server, mach_msg_server)