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 (at) 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 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
