1 /*
2 * pthread_rwlock_timedwrlock.c
3 *
4 * Description:
5 * This translation unit implements read/write lock primitives.
6 *
7 * --------------------------------------------------------------------------
8 *
9 * Pthreads-win32 - POSIX Threads Library for Win32
10 * Copyright(C) 1998 John E. Bossom
11 * Copyright(C) 1999,2005 Pthreads-win32 contributors
12 *
13 * Contact Email: rpj@callisto.canberra.edu.au
14 *
15 * The current list of contributors is contained
16 * in the file CONTRIBUTORS included with the source
17 * code distribution. The list can also be seen at the
18 * following World Wide Web location:
19 * http://sources.redhat.com/pthreads-win32/contributors.html
20 *
21 * This library is free software; you can redistribute it and/or
22 * modify it under the terms of the GNU Lesser General Public
23 * License as published by the Free Software Foundation; either
24 * version 2 of the License, or (at your option) any later version.
25 *
26 * This library is distributed in the hope that it will be useful,
27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
29 * Lesser General Public License for more details.
30 *
31 * You should have received a copy of the GNU Lesser General Public
32 * License along with this library in the file COPYING.LIB;
33 * if not, write to the Free Software Foundation, Inc.,
34 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
35 */
36
37 #include <limits.h>
38
39 #include "pthread.h"
40 #include "implement.h"
41
42 int
pthread_rwlock_timedwrlock(pthread_rwlock_t * rwlock,const struct timespec * abstime)43 pthread_rwlock_timedwrlock (pthread_rwlock_t * rwlock,
44 const struct timespec *abstime)
45 {
46 int result;
47 pthread_rwlock_t rwl;
48
49 if (rwlock == NULL || *rwlock == NULL)
50 {
51 return EINVAL;
52 }
53
54 /*
55 * We do a quick check to see if we need to do more work
56 * to initialise a static rwlock. We check
57 * again inside the guarded section of ptw32_rwlock_check_need_init()
58 * to avoid race conditions.
59 */
60 if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
61 {
62 result = ptw32_rwlock_check_need_init (rwlock);
63
64 if (result != 0 && result != EBUSY)
65 {
66 return result;
67 }
68 }
69
70 rwl = *rwlock;
71
72 if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
73 {
74 return EINVAL;
75 }
76
77 if ((result =
78 pthread_mutex_timedlock (&(rwl->mtxExclusiveAccess), abstime)) != 0)
79 {
80 return result;
81 }
82
83 if ((result =
84 pthread_mutex_timedlock (&(rwl->mtxSharedAccessCompleted),
85 abstime)) != 0)
86 {
87 (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
88 return result;
89 }
90
91 if (rwl->nExclusiveAccessCount == 0)
92 {
93 if (rwl->nCompletedSharedAccessCount > 0)
94 {
95 rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
96 rwl->nCompletedSharedAccessCount = 0;
97 }
98
99 if (rwl->nSharedAccessCount > 0)
100 {
101 rwl->nCompletedSharedAccessCount = -rwl->nSharedAccessCount;
102
103 /*
104 * This routine may be a cancelation point
105 * according to POSIX 1003.1j section 18.1.2.
106 */
107 #if defined(_MSC_VER) && _MSC_VER < 1400
108 #pragma inline_depth(0)
109 #endif
110 pthread_cleanup_push (ptw32_rwlock_cancelwrwait, (void *) rwl);
111
112 do
113 {
114 result =
115 pthread_cond_timedwait (&(rwl->cndSharedAccessCompleted),
116 &(rwl->mtxSharedAccessCompleted),
117 abstime);
118 }
119 while (result == 0 && rwl->nCompletedSharedAccessCount < 0);
120
121 pthread_cleanup_pop ((result != 0) ? 1 : 0);
122 #if defined(_MSC_VER) && _MSC_VER < 1400
123 #pragma inline_depth()
124 #endif
125
126 if (result == 0)
127 {
128 rwl->nSharedAccessCount = 0;
129 }
130 }
131 }
132
133 if (result == 0)
134 {
135 rwl->nExclusiveAccessCount++;
136 }
137
138 return result;
139 }
140