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
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
|
/*
* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <stdlib.h>
#include <errno.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
int
pthread_cond_init(pthread_cond_t * cond, const pthread_condattr_t * cond_attr)
{
enum pthread_cond_type type;
int rval = 0;
/*
* Check if a pointer to a condition variable attribute structure was
* passed by the caller:
*/
if (cond_attr != NULL) {
/* Default to a fast condition variable: */
type = cond_attr->c_type;
} else {
/* Default to a fast condition variable: */
type = COND_TYPE_FAST;
}
/* Process according to condition variable type: */
switch (type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Nothing to do here. */
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Check for no errors: */
if (rval == 0) {
/* Initialise the condition variable structure: */
_thread_queue_init(&cond->c_queue);
cond->c_flags |= COND_FLAGS_INITED;
cond->c_type = type;
}
/* Return the completion status: */
return (rval);
}
int
pthread_cond_destroy(pthread_cond_t * cond)
{
int rval = 0;
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Nothing to do here. */
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Check for errors: */
if (rval == 0) {
/* Destroy the contents of the condition structure: */
_thread_queue_init(&cond->c_queue);
cond->c_flags = 0;
}
/* Return the completion status: */
return (rval);
}
int
pthread_cond_wait(pthread_cond_t * cond, pthread_mutex_t * mutex)
{
int rval = 0;
int status;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Queue the running thread for the condition variable: */
_thread_queue_enq(&cond->c_queue, _thread_run);
/* Unlock the mutex: */
pthread_mutex_unlock(mutex);
/* Schedule the next thread: */
_thread_kern_sched_state(PS_COND_WAIT, __FILE__, __LINE__);
/* Block signals: */
_thread_kern_sig_block(NULL);
/* Lock the mutex: */
rval = pthread_mutex_lock(mutex);
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
int
pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex,
const struct timespec * abstime)
{
int rval = 0;
int status;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Set the wakeup time: */
_thread_run->wakeup_time.ts_sec = abstime->ts_sec;
_thread_run->wakeup_time.ts_nsec = abstime->ts_nsec;
/* Reset the timeout flag: */
_thread_run->timeout = 0;
/* Queue the running thread for the condition variable: */
_thread_queue_enq(&cond->c_queue, _thread_run);
/* Unlock the mutex: */
if ((rval = pthread_mutex_unlock(mutex)) != 0) {
/*
* Cannot unlock the mutex, so remove the running
* thread from the condition variable queue:
*/
_thread_queue_deq(&cond->c_queue);
} else {
/* Schedule the next thread: */
_thread_kern_sched_state(PS_COND_WAIT, __FILE__, __LINE__);
/* Block signals: */
_thread_kern_sig_block(NULL);
/* Lock the mutex: */
if ((rval = pthread_mutex_lock(mutex)) != 0) {
}
/* Check if the wait timed out: */
else if (_thread_run->timeout) {
/* Return a timeout error: */
_thread_seterrno(_thread_run, EAGAIN);
rval = -1;
}
}
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
int
pthread_cond_signal(pthread_cond_t * cond)
{
int rval = 0;
int status;
pthread_t pthread;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Bring the next thread off the condition queue: */
if ((pthread = _thread_queue_deq(&cond->c_queue)) != NULL) {
/* Allow the thread to run: */
pthread->state = PS_RUNNING;
}
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
int
pthread_cond_broadcast(pthread_cond_t * cond)
{
int rval = 0;
int status;
pthread_t pthread;
/* Block signals: */
_thread_kern_sig_block(&status);
/* Process according to condition variable type: */
switch (cond->c_type) {
/* Fast condition variable: */
case COND_TYPE_FAST:
/* Enter a loop to bring all threads off the condition queue: */
while ((pthread = _thread_queue_deq(&cond->c_queue)) != NULL) {
/* Allow the thread to run: */
pthread->state = PS_RUNNING;
}
break;
/* Trap invalid condition variable types: */
default:
/* Return an invalid argument error: */
_thread_seterrno(_thread_run, EINVAL);
rval = -1;
break;
}
/* Unblock signals: */
_thread_kern_sig_unblock(status);
/* Return the completion status: */
return (rval);
}
#endif
|
