forked from xythian/wp-lambdamoo
-
Notifications
You must be signed in to change notification settings - Fork 0
/
net_mp_fake.c
190 lines (164 loc) · 4.5 KB
/
net_mp_fake.c
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
/******************************************************************************
Copyright (c) 1992, 1995, 1996 Xerox Corporation. All rights reserved.
Portions of this code were written by Stephen White, aka ghond.
Use and copying of this software and preparation of derivative works based
upon this software are permitted. Any distribution of this software or
derivative works must comply with all applicable United States export
control laws. This software is made available AS IS, and Xerox Corporation
makes no warranty about the software, its performance or its conformity to
any specification. Any person obtaining a copy of this software is requested
to send their name and post office or electronic mail address to:
Pavel Curtis
Xerox PARC
3333 Coyote Hill Rd.
Palo Alto, CA 94304
*****************************************************************************/
/* Multiplexing wait implementation using fstat (only works for FIFOs) */
#include "my-types.h"
#include "my-stat.h"
#include "my-unistd.h" /* sleep() */
#include "net_mplex.h"
#include "options.h"
#include "storage.h"
#if (NETWORK_PROTOCOL != NP_LOCAL) || (NETWORK_STYLE != NS_SYSV)
#error Configuration Error: this code can only be used with the FIFO protocol
#endif
typedef enum {
Read, Write
} Direction;
typedef struct {
int fd;
Direction dir;
} Port;
static Port *ports = 0;
static int num_ports = 0;
static int max_ports = 0;
static char *readable = 0;
static char *writable = 0;
static int rw_size = 0;
void
mplex_clear(void)
{
int i;
num_ports = 0;
for (i = 0; i < rw_size; i++)
readable[i] = writable[i] = 0;
}
static void
add_common(int fd, Direction dir)
{
if (fd >= rw_size) { /* Grow readable/writable arrays */
int new_size = (fd + 9) / 10 * 10 + 1;
char *new_readable = (char *) mymalloc(new_size * sizeof(char),
M_NETWORK);
char *new_writable = (char *) mymalloc(new_size * sizeof(char),
M_NETWORK);
int i;
for (i = 0; i < new_size; i++)
new_readable[i] = new_writable[i] = 0;
if (readable != 0) {
myfree(readable, M_NETWORK);
myfree(writable, M_NETWORK);
}
readable = new_readable;
writable = new_writable;
rw_size = new_size;
}
if (num_ports == max_ports) { /* Grow ports array */
int new_max = max_ports + 10;
Port *new_ports = mymalloc(new_max * sizeof(Port), M_NETWORK);
int i;
for (i = 0; i < max_ports; i++)
new_ports[i] = ports[i];
if (ports != 0)
myfree(ports, M_NETWORK);
ports = new_ports;
max_ports = new_max;
}
ports[num_ports].fd = fd;
ports[num_ports++].dir = dir;
}
void
mplex_add_reader(int fd)
{
add_common(fd, Read);
}
void
mplex_add_writer(int fd)
{
add_common(fd, Write);
}
int
mplex_wait(unsigned timeout)
{
struct stat st;
int i, got_one = 0;
while (1) {
for (i = 0; i < num_ports; i++) {
fstat(ports[i].fd, &st);
if (ports[i].dir == Read) {
if (st.st_size > 0) {
readable[ports[i].fd] = 1;
got_one = 1;
}
} else {
/* The following is a bit of unavoidable crockery. Since we
* don't know how much the server wants to write, and since
* writes of less than the size of a FIFO buffer are atomic,
* we can't really tell whether or not a write() will be
* successful. This approximation keeps us from ever
* busy-waiting.
*/
if (st.st_size == 0) {
writable[ports[i].fd] = 1;
got_one = 1;
}
}
}
if (got_one)
break;
else if (timeout-- > 0)
sleep(1);
}
return !got_one;
}
int
mplex_is_readable(int fd)
{
return (fd < rw_size) ? readable[fd] : 0;
}
int
mplex_is_writable(int fd)
{
return (fd < rw_size) ? writable[fd] : 0;
}
char rcsid_net_mp_fake[] = "$Id$";
/* $Log$
/* Revision 1.2 1997/03/03 04:19:03 nop
/* GNU Indent normalization
/*
* Revision 1.1.1.1 1997/03/03 03:45:02 nop
* LambdaMOO 1.8.0p5
*
* Revision 2.1 1996/02/08 06:36:06 pavel
* Updated copyright notice for 1996. Release 1.8.0beta1.
*
* Revision 2.0 1995/11/30 04:46:24 pavel
* New baseline version, corresponding to release 1.8.0alpha1.
*
* Revision 1.5 1992/10/23 23:03:47 pavel
* Added copyright notice.
*
* Revision 1.4 1992/10/23 19:38:16 pavel
* #includes "my-stat.h" instead of <sys/stat.h>.
*
* Revision 1.3 1992/10/21 03:02:35 pavel
* Converted to use new automatic configuration system.
*
* Revision 1.2 1992/10/02 18:50:25 pavel
* Removed useless #include of log.h.
*
* Revision 1.1 1992/10/02 17:54:10 pavel
* Initial RCS-controlled version.
*/