1 /*
2 * pthread_mutex_unlock.c
3 *
4 * Description:
5 * This translation unit implements mutual exclusion (mutex) 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 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
35 */
36
37 #include "pthread.h"
38 #include "implement.h"
39
40
41 int
pthread_mutex_unlock(pthread_mutex_t * mutex)42 pthread_mutex_unlock (pthread_mutex_t * mutex)
43 {
44 int result = 0;
45 int kind;
46 pthread_mutex_t mx;
47
48 /*
49 * Let the system deal with invalid pointers.
50 */
51
52 mx = *mutex;
53
54 /*
55 * If the thread calling us holds the mutex then there is no
56 * race condition. If another thread holds the
57 * lock then we shouldn't be in here.
58 */
59 if (mx < PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
60 {
61 kind = mx->kind;
62
63 if (kind >= 0)
64 {
65 if (kind == PTHREAD_MUTEX_NORMAL)
66 {
67 LONG idx;
68
69 idx = (LONG) PTW32_INTERLOCKED_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR)&mx->lock_idx,
70 (PTW32_INTERLOCKED_LONG)0);
71 if (idx != 0)
72 {
73 if (idx < 0)
74 {
75 /*
76 * Someone may be waiting on that mutex.
77 */
78 if (SetEvent (mx->event) == 0)
79 {
80 result = EINVAL;
81 }
82 }
83 }
84 }
85 else
86 {
87 if (pthread_equal (mx->ownerThread, pthread_self()))
88 {
89 if (kind != PTHREAD_MUTEX_RECURSIVE
90 || 0 == --mx->recursive_count)
91 {
92 mx->ownerThread.p = NULL;
93
94 if ((LONG) PTW32_INTERLOCKED_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR)&mx->lock_idx,
95 (PTW32_INTERLOCKED_LONG)0) < 0L)
96 {
97 /* Someone may be waiting on that mutex */
98 if (SetEvent (mx->event) == 0)
99 {
100 result = EINVAL;
101 }
102 }
103 }
104 }
105 else
106 {
107 result = EPERM;
108 }
109 }
110 }
111 else
112 {
113 /* Robust types */
114 pthread_t self = pthread_self();
115 kind = -kind - 1; /* Convert to non-robust range */
116
117 /*
118 * The thread must own the lock regardless of type if the mutex
119 * is robust.
120 */
121 if (pthread_equal (mx->ownerThread, self))
122 {
123 PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG((PTW32_INTERLOCKED_LONGPTR) &mx->robustNode->stateInconsistent,
124 (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_NOTRECOVERABLE,
125 (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_INCONSISTENT);
126 if (PTHREAD_MUTEX_NORMAL == kind)
127 {
128 ptw32_robust_mutex_remove(mutex, NULL);
129
130 if ((LONG) PTW32_INTERLOCKED_EXCHANGE_LONG((PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx,
131 (PTW32_INTERLOCKED_LONG) 0) < 0)
132 {
133 /*
134 * Someone may be waiting on that mutex.
135 */
136 if (SetEvent (mx->event) == 0)
137 {
138 result = EINVAL;
139 }
140 }
141 }
142 else
143 {
144 if (kind != PTHREAD_MUTEX_RECURSIVE
145 || 0 == --mx->recursive_count)
146 {
147 ptw32_robust_mutex_remove(mutex, NULL);
148
149 if ((LONG) PTW32_INTERLOCKED_EXCHANGE_LONG((PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx,
150 (PTW32_INTERLOCKED_LONG) 0) < 0)
151 {
152 /*
153 * Someone may be waiting on that mutex.
154 */
155 if (SetEvent (mx->event) == 0)
156 {
157 result = EINVAL;
158 }
159 }
160 }
161 }
162 }
163 else
164 {
165 result = EPERM;
166 }
167 }
168 }
169 else if (mx != PTHREAD_MUTEX_INITIALIZER)
170 {
171 result = EINVAL;
172 }
173
174 return (result);
175 }
176