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
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/* This file is part of the Project Athena Zephyr Notification System.
* It is one of the source files comprising zwgc, the Zephyr WindowGram
* client.
*
* Created by: Marc Horowitz <marc@athena.mit.edu>
*
* $Id$
*
* Copyright (c) 1989 by the Massachusetts Institute of Technology.
* For copying and distribution information, see the file
* "mit-copyright.h".
*/
#include <sysdep.h>
#if (!defined(lint) && !defined(SABER))
static const char rcsid_mux_c[] = "$Id$";
#endif
/****************************************************************************/
/* */
/* Module containing code to wait on multiple file descriptors: */
/* */
/****************************************************************************/
#include <zephyr/zephyr.h>
#include "main.h"
#include "mux.h"
#include "error.h"
#include "zwgc.h"
#include "pointer.h"
#ifdef CMU_ZWGCPLUS
#include "plus.h"
#endif
#ifdef _AIX
#include <sys/select.h>
#endif
/*
* mux_end_loop_p - Setting this to true during a mux_loop causes the mux_loop
* to be exited.
*/
int mux_end_loop_p;
/*
* have_tty - is defined to be true if there is a controlling tty for this
* process. When we can no longer access the controlling tty,
* the process will die.
*/
static int have_tty = 0;
/*
* max_source - the maximum file descriptor that a handler was ever
* registered for:
*/
static int max_source = -1;
/*
* Which file descriptors we're waiting on for input & the accompanying
* input handlers & their arguments:
*/
static fd_set input_sources;
static void (*input_handler[MAX_SOURCES])(void *);
static pointer input_handler_arg[MAX_SOURCES];
static int check_tty(void);
/*
* void mux_init()
* Requires: mux_init has never been called before
* Effects: Initializes the mux module. Must be called before
* any other mux call.
*/
void
mux_init(void)
{
int i;
FD_ZERO(&input_sources);
for (i=0; i<MAX_SOURCES; i++)
input_handler[i] = NULL;
have_tty = check_tty();
}
/*
* void mux_add_input_source(int descriptor; void (*handler)(); pointer arg)
* Requires: 0<=descriptor<MAX_SOURCES, mux_init has been called
* Modifies: Removes the previous input handler if any for descriptor
* Effects: Registers handler as the input handler for file descriptor
* descriptor. When mux_loop() is running and input is
* available on descriptor, handler will be called with
* argument arg.
*/
void
mux_add_input_source(int descriptor,
void (*handler)(void *),
pointer arg)
{
#ifdef DEBUG
if(descriptor < 0 || descriptor >= MAX_SOURCES)
abort(); /* <<<>>> */
#endif
input_handler[descriptor] = handler;
input_handler_arg[descriptor] = arg;
FD_SET(descriptor, &input_sources);
if(descriptor > max_source)
max_source = descriptor;
}
/*
* void mux_loop()
* Requires: mux_init has been called.
* Effects: Loops until mux_end_loop_p becomes true. (Sets
* mux_end_loop_p false to start). Whenever input is
* available on an input source which has a registered
* handler (see mux_add_input_source), that handler is
* called with its argument. It is guaranteed that if
* input is available on a source, its respective input
* handler, if any, will eventually be called. No other
* ordering guarantees are made. When some signal handler
* or input handler eventually sets mux_end_loop_p to
* true, we return.
*/
void
mux_loop(void)
{
int i, nfds;
fd_set inputs, outputs;
struct timeval tv, *tvp;
mux_end_loop_p = 0;
for (;;) {
/*
* Exit if mux_end_loop_p has been set to true by a handler:
*/
if (mux_end_loop_p)
break;
tvp = NULL;
tv.tv_sec = 0;
if (have_tty) {
#ifdef CMU_ZWGCPLUS
tv.tv_sec = plus_timequeue_events();
if (tv.tv_sec > 10) tv.tv_sec = 10;
#else
tv.tv_sec = 10;
#endif
tv.tv_usec = 0;
#ifdef CMU_ZWGCPLUS
} else {
tv.tv_sec = plus_timequeue_events();
tv.tv_usec = 0;
#endif
}
if (tv.tv_sec)
tvp = &tv;
/*
* Do a select on all the file descriptors we care about to
* wait until at least one of them has input available:
*/
inputs = input_sources;
FD_ZERO(&outputs);
#ifdef HAVE_ARES
nfds = ares_fds(achannel, &inputs, &outputs);
if (nfds < max_source + 1)
nfds = max_source + 1;
tvp = ares_timeout(achannel, tvp, &tv);
#else
nfds = max_source + 1;
#endif
i = select(nfds, &inputs, &outputs, NULL, tvp);
if (i == -1) {
if (errno == EINTR)
continue; /* on a signal restart checking mux_loop_end_p */
else
FATAL_TRAP( errno, "while selecting" );
}
else if (i == 0) {
if (have_tty && !check_tty()) {
mux_end_loop_p = 1;
continue;
}
}
#ifdef HAVE_ARES
ares_process(achannel, &inputs, &outputs);
#endif
/*
* Call all input handlers whose corresponding file descriptors have
* input:
*/
for(i=0; i<=max_source; i++)
if (FD_ISSET(i, &inputs) && input_handler[i]) {
#ifdef DEBUG
if (zwgc_debug)
fprintf(stderr,
"mux_loop...activity on fd %d, calling %x(%x)\n",
i,input_handler[i],input_handler_arg[i]);
#endif
input_handler[i](input_handler_arg[i]);
}
}
}
static int
check_tty(void)
{
register int result;
int pgrp;
int tty = open("/dev/tty", O_RDONLY|O_NDELAY);
if (tty < 0) return 0;
#if defined(_POSIX_VERSION)
result = ( ((pgrp = tcgetpgrp(tty)) < 0) ? 0 : 1 );
#else
result = ( (ioctl(tty, TIOCGPGRP, &pgrp) < 0) ? 0 : 1 );
#endif
close(tty);
return(result);
}
|
