| /* |
| * pthread_mutex_trylock.c |
| * |
| * Description: |
| * This translation unit implements mutual exclusion (mutex) primitives. |
| * |
| * -------------------------------------------------------------------------- |
| * |
| * Pthreads-win32 - POSIX Threads Library for Win32 |
| * Copyright(C) 1998 John E. Bossom |
| * Copyright(C) 1999,2005 Pthreads-win32 contributors |
| * |
| * Contact Email: rpj@callisto.canberra.edu.au |
| * |
| * The current list of contributors is contained |
| * in the file CONTRIBUTORS included with the source |
| * code distribution. The list can also be seen at the |
| * following World Wide Web location: |
| * http://sources.redhat.com/pthreads-win32/contributors.html |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library in the file COPYING.LIB; |
| * if not, write to the Free Software Foundation, Inc., |
| * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA |
| */ |
| |
| #include "pthread.h" |
| #include "implement.h" |
| |
| |
| int |
| pthread_mutex_trylock (pthread_mutex_t * mutex) |
| { |
| pthread_mutex_t mx; |
| int kind; |
| int result = 0; |
| |
| /* |
| * Let the system deal with invalid pointers. |
| */ |
| |
| /* |
| * We do a quick check to see if we need to do more work |
| * to initialise a static mutex. We check |
| * again inside the guarded section of ptw32_mutex_check_need_init() |
| * to avoid race conditions. |
| */ |
| if (*mutex >= PTHREAD_ERRORCHECK_MUTEX_INITIALIZER) |
| { |
| if ((result = ptw32_mutex_check_need_init (mutex)) != 0) |
| { |
| return (result); |
| } |
| } |
| |
| mx = *mutex; |
| kind = mx->kind; |
| |
| if (kind >= 0) |
| { |
| /* Non-robust */ |
| if (0 == (PTW32_INTERLOCKED_LONG) PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ( |
| (PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx, |
| (PTW32_INTERLOCKED_LONG) 1, |
| (PTW32_INTERLOCKED_LONG) 0)) |
| { |
| if (kind != PTHREAD_MUTEX_NORMAL) |
| { |
| mx->recursive_count = 1; |
| mx->ownerThread = pthread_self (); |
| } |
| } |
| else |
| { |
| if (kind == PTHREAD_MUTEX_RECURSIVE && |
| pthread_equal (mx->ownerThread, pthread_self ())) |
| { |
| mx->recursive_count++; |
| } |
| else |
| { |
| result = EBUSY; |
| } |
| } |
| } |
| else |
| { |
| /* |
| * Robust types |
| * All types record the current owner thread. |
| * The mutex is added to a per thread list when ownership is acquired. |
| */ |
| pthread_t self; |
| ptw32_robust_state_t* statePtr = &mx->robustNode->stateInconsistent; |
| |
| if ((PTW32_INTERLOCKED_LONG)PTW32_ROBUST_NOTRECOVERABLE == |
| PTW32_INTERLOCKED_EXCHANGE_ADD_LONG( |
| (PTW32_INTERLOCKED_LONGPTR)statePtr, |
| (PTW32_INTERLOCKED_LONG)0)) |
| { |
| return ENOTRECOVERABLE; |
| } |
| |
| self = pthread_self(); |
| kind = -kind - 1; /* Convert to non-robust range */ |
| |
| if (0 == (PTW32_INTERLOCKED_LONG) PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ( |
| (PTW32_INTERLOCKED_LONGPTR) &mx->lock_idx, |
| (PTW32_INTERLOCKED_LONG) 1, |
| (PTW32_INTERLOCKED_LONG) 0)) |
| { |
| if (kind != PTHREAD_MUTEX_NORMAL) |
| { |
| mx->recursive_count = 1; |
| } |
| ptw32_robust_mutex_add(mutex, self); |
| } |
| else |
| { |
| if (PTHREAD_MUTEX_RECURSIVE == kind && |
| pthread_equal (mx->ownerThread, pthread_self ())) |
| { |
| mx->recursive_count++; |
| } |
| else |
| { |
| if (EOWNERDEAD == (result = ptw32_robust_mutex_inherit(mutex))) |
| { |
| mx->recursive_count = 1; |
| ptw32_robust_mutex_add(mutex, self); |
| } |
| else |
| { |
| if (0 == result) |
| { |
| result = EBUSY; |
| } |
| } |
| } |
| } |
| } |
| |
| return (result); |
| } |