1 /* 2 * pthread_rwlock_timedrdlock.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 (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 <limits.h> 38 39 #include "pthread.h" 40 #include "implement.h" 41 42 int 43 pthread_rwlock_timedrdlock (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 (++rwl->nSharedAccessCount == INT_MAX) 84 { 85 if ((result = 86 pthread_mutex_timedlock (&(rwl->mtxSharedAccessCompleted), 87 abstime)) != 0) 88 { 89 if (result == ETIMEDOUT) 90 { 91 ++rwl->nCompletedSharedAccessCount; 92 } 93 (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess)); 94 return result; 95 } 96 97 rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount; 98 rwl->nCompletedSharedAccessCount = 0; 99 100 if ((result = 101 pthread_mutex_unlock (&(rwl->mtxSharedAccessCompleted))) != 0) 102 { 103 (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess)); 104 return result; 105 } 106 } 107 108 return (pthread_mutex_unlock (&(rwl->mtxExclusiveAccess))); 109 } 110