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
|
/*
* BRLTTY - A background process providing access to the console screen (when in
* text mode) for a blind person using a refreshable braille display.
*
* Copyright (C) 1995-2025 by The BRLTTY Developers.
*
* BRLTTY comes with ABSOLUTELY NO WARRANTY.
*
* This is free software, placed 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. Please see the file LICENSE-LGPL for details.
*
* Web Page: http://brltty.app/
*
* This software is maintained by Dave Mielke <dave@mielke.cc>.
*/
#include "prologue.h"
#include <string.h>
#include <errno.h>
#include <sys/msg.h>
#include "log.h"
#include "msg_queue.h"
#include "async_event.h"
#include "thread.h"
typedef struct {
MessageType type;
char content[];
} Message;
#define MESSAGE(name, length) \
unsigned char name##_bytes[sizeof(MessageType) + (length)]; \
Message *name = (void *)name##_bytes;
int
sendMessage (int queue, MessageType type, const void *content, size_t length, int flags) {
MESSAGE(message, length);
if (!content) {
length = 0;
} else if (length) {
memcpy(message->content, content, length);
}
message->type = type;
if (msgsnd(queue, message, length, flags) != -1) return 1;
logSystemError("msgsnd");
return 0;
}
ssize_t
receiveMessage (int queue, MessageType *type, void *buffer, size_t size, int flags) {
MESSAGE(message, size);
if (!buffer) size = 0;
ssize_t length = msgrcv(queue, message, size, *type, flags);
if (length != -1) {
*type = message->type;
if (length) memcpy(buffer, message->content, length);
} else if (errno != EIDRM) {
logSystemError("msgrcv");
}
return length;
}
typedef struct {
AsyncEvent *event;
pthread_t thread;
MessageHandler *handler;
void *data;
int queue;
MessageType type;
size_t size;
} MessageReceiverArgument;
ASYNC_EVENT_CALLBACK(handleReceivedMessage) {
MessageReceiverArgument *mra = parameters->eventData;
MessageHandlerParameters *mhp = parameters->signalData;
if (mhp) {
mra->handler(mhp);
free(mhp);
} else {
void *result;
pthread_join(mra->thread, &result);
asyncDiscardEvent(mra->event);
free(mra);
}
}
THREAD_FUNCTION(messageReceiverThread) {
MessageReceiverArgument *mra = argument;
char buffer[mra->size];
while (1) {
MessageType type = mra->type;
ssize_t length = receiveMessage(mra->queue, &type, buffer, mra->size, 0);
if (length != -1) {
MessageHandlerParameters *mhp;
if ((mhp = malloc(sizeof(*mhp) + length))) {
memset(mhp, 0, sizeof(*mhp));
mhp->data = mra->data;
mhp->type = type;
mhp->length = length;
memcpy(mhp->content, buffer, mhp->length);
if (asyncSignalEvent(mra->event, mhp)) continue;
free(mhp);
} else {
logMallocError();
}
}
break;
}
asyncSignalEvent(mra->event, NULL);
return NULL;
}
int
startMessageReceiver (const char *name, int queue, MessageType type, size_t size, MessageHandler *handler, void *data) {
MessageReceiverArgument *mra;
if ((mra = malloc(sizeof(*mra)))) {
memset(mra, 0, sizeof(*mra));
mra->handler = handler;
mra->data = data;
mra->queue = queue;
mra->type = type;
mra->size = size;
if ((mra->event = asyncNewEvent(handleReceivedMessage, mra))) {
int threadCreationError = createThread(name, &mra->thread, NULL, messageReceiverThread, mra);
if (!threadCreationError) {
logMessage(LOG_DEBUG, "message receiver started: %s", name);
return 1;
}
asyncDiscardEvent(mra->event);
}
free(mra);
} else {
logMallocError();
}
logMessage(LOG_WARNING, "message receiver not started: %s", name);
return 0;
}
|
