1 /*
2 * pthread_mutex_destroy.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_destroy(pthread_mutex_t * mutex)42 pthread_mutex_destroy (pthread_mutex_t * mutex)
43 {
44 int result = 0;
45 pthread_mutex_t mx;
46
47 /*
48 * Let the system deal with invalid pointers.
49 */
50
51 /*
52 * Check to see if we have something to delete.
53 */
54 if (*mutex < PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
55 {
56 mx = *mutex;
57
58 result = pthread_mutex_trylock (&mx);
59
60 /*
61 * If trylock succeeded and the mutex is not recursively locked it
62 * can be destroyed.
63 */
64 if (0 == result || ENOTRECOVERABLE == result)
65 {
66 if (mx->kind != PTHREAD_MUTEX_RECURSIVE || 1 == mx->recursive_count)
67 {
68 /*
69 * FIXME!!!
70 * The mutex isn't held by another thread but we could still
71 * be too late invalidating the mutex below since another thread
72 * may already have entered mutex_lock and the check for a valid
73 * *mutex != NULL.
74 */
75 *mutex = NULL;
76
77 result = (0 == result)?pthread_mutex_unlock(&mx):0;
78
79 if (0 == result)
80 {
81 if (mx->robustNode != NULL)
82 {
83 free(mx->robustNode);
84 }
85 if (!CloseHandle (mx->event))
86 {
87 *mutex = mx;
88 result = EINVAL;
89 }
90 else
91 {
92 free (mx);
93 }
94 }
95 else
96 {
97 /*
98 * Restore the mutex before we return the error.
99 */
100 *mutex = mx;
101 }
102 }
103 else /* mx->recursive_count > 1 */
104 {
105 /*
106 * The mutex must be recursive and already locked by us (this thread).
107 */
108 mx->recursive_count--; /* Undo effect of pthread_mutex_trylock() above */
109 result = EBUSY;
110 }
111 }
112 }
113 else
114 {
115 ptw32_mcs_local_node_t node;
116
117 /*
118 * See notes in ptw32_mutex_check_need_init() above also.
119 */
120
121 ptw32_mcs_lock_acquire(&ptw32_mutex_test_init_lock, &node);
122
123 /*
124 * Check again.
125 */
126 if (*mutex >= PTHREAD_ERRORCHECK_MUTEX_INITIALIZER)
127 {
128 /*
129 * This is all we need to do to destroy a statically
130 * initialised mutex that has not yet been used (initialised).
131 * If we get to here, another thread
132 * waiting to initialise this mutex will get an EINVAL.
133 */
134 *mutex = NULL;
135 }
136 else
137 {
138 /*
139 * The mutex has been initialised while we were waiting
140 * so assume it's in use.
141 */
142 result = EBUSY;
143 }
144 ptw32_mcs_lock_release(&node);
145 }
146
147 return (result);
148 }
149