[395de1]: sem_timedwait.c Maximize Restore History

Download this file

sem_timedwait.c    239 lines (210 with data), 6.4 kB

  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
/*
* -------------------------------------------------------------
*
* Module: sem_timedwait.c
*
* Purpose:
* Semaphores aren't actually part of the PThreads standard.
* They are defined by the POSIX Standard:
*
* POSIX 1003.1b-1993 (POSIX.1b)
*
* -------------------------------------------------------------
*
* --------------------------------------------------------------------------
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2005 Pthreads-win32 contributors
*
* Contact Email: rpj@callisto.canberra.edu.au
*
* The current list of contributors is contained
* in the file CONTRIBUTORS included with the source
* code distribution. The list can also be seen at the
* following World Wide Web location:
* http://sources.redhat.com/pthreads-win32/contributors.html
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library in the file COPYING.LIB;
* if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include "pthread.h"
#include "semaphore.h"
#include "implement.h"
typedef struct {
sem_t sem;
int * resultPtr;
} sem_timedwait_cleanup_args_t;
static void PTW32_CDECL
ptw32_sem_timedwait_cleanup (void * args)
{
sem_timedwait_cleanup_args_t * a = (sem_timedwait_cleanup_args_t *)args;
sem_t s = a->sem;
if (pthread_mutex_lock (&s->lock) == 0)
{
/*
* We either timed out or were cancelled.
* If someone has posted between then and now we try to take the semaphore.
* Otherwise the semaphore count may be wrong after we
* return. In the case of a cancellation, it is as if we
* were cancelled just before we return (after taking the semaphore)
* which is ok.
*/
if (WaitForSingleObject(s->sem, 0) == WAIT_OBJECT_0)
{
/* We got the semaphore on the second attempt */
*(a->resultPtr) = 0;
}
else
{
/* Indicate we're no longer waiting */
s->value++;
#ifdef NEED_SEM
if (s->value > 0)
{
s->leftToUnblock = 0;
}
#else
/*
* Don't release the W32 sema, it doesn't need adjustment
* because it doesn't record the number of waiters.
*/
#endif
}
(void) pthread_mutex_unlock (&s->lock);
}
}
int
sem_timedwait (sem_t * sem, const struct timespec *abstime)
/*
* ------------------------------------------------------
* DOCPUBLIC
* This function waits on a semaphore possibly until
* 'abstime' time.
*
* PARAMETERS
* sem
* pointer to an instance of sem_t
*
* abstime
* pointer to an instance of struct timespec
*
* DESCRIPTION
* This function waits on a semaphore. If the
* semaphore value is greater than zero, it decreases
* its value by one. If the semaphore value is zero, then
* the calling thread (or process) is blocked until it can
* successfully decrease the value or until interrupted by
* a signal.
*
* If 'abstime' is a NULL pointer then this function will
* block until it can successfully decrease the value or
* until interrupted by a signal.
*
* RESULTS
* 0 successfully decreased semaphore,
* -1 failed, error in errno
* ERRNO
* EINVAL 'sem' is not a valid semaphore,
* ENOSYS semaphores are not supported,
* EINTR the function was interrupted by a signal,
* EDEADLK a deadlock condition was detected.
* ETIMEDOUT abstime elapsed before success.
*
* ------------------------------------------------------
*/
{
int result = 0;
sem_t s = *sem;
pthread_testcancel();
if (sem == NULL)
{
result = EINVAL;
}
else
{
DWORD milliseconds;
if (abstime == NULL)
{
milliseconds = INFINITE;
}
else
{
/*
* Calculate timeout as milliseconds from current system time.
*/
milliseconds = ptw32_relmillisecs (abstime);
}
if ((result = pthread_mutex_lock (&s->lock)) == 0)
{
int v;
/* See sem_destroy.c
*/
if (*sem == NULL)
{
(void) pthread_mutex_unlock (&s->lock);
errno = EINVAL;
return -1;
}
v = --s->value;
(void) pthread_mutex_unlock (&s->lock);
if (v < 0)
{
#ifdef NEED_SEM
int timedout;
#endif
sem_timedwait_cleanup_args_t cleanup_args;
cleanup_args.sem = s;
cleanup_args.resultPtr = &result;
#if defined(_MSC_VER) && _MSC_VER < 800
#pragma inline_depth(0)
#endif
/* Must wait */
pthread_cleanup_push(ptw32_sem_timedwait_cleanup, (void *) &cleanup_args);
#ifdef NEED_SEM
timedout =
#endif
result = pthreadCancelableTimedWait (s->sem, milliseconds);
pthread_cleanup_pop(result);
#if defined(_MSC_VER) && _MSC_VER < 800
#pragma inline_depth()
#endif
#ifdef NEED_SEM
if (!timedout && pthread_mutex_lock (&s->lock) == 0)
{
if (*sem == NULL)
{
(void) pthread_mutex_unlock (&s->lock);
errno = EINVAL;
return -1;
}
if (s->leftToUnblock > 0)
{
--s->leftToUnblock;
SetEvent(s->sem);
}
(void) pthread_mutex_unlock (&s->lock);
}
#endif /* NEED_SEM */
}
}
}
if (result != 0)
{
errno = result;
return -1;
}
return 0;
} /* sem_timedwait */