| /* |
| * pthread_mutex_consistent.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 |
| */ |
| |
| /* |
| * From the Sun Multi-threaded Programming Guide |
| * |
| * robustness defines the behavior when the owner of the mutex terminates without unlocking the |
| * mutex, usually because its process terminated abnormally. The value of robustness that is |
| * defined in pthread.h is PTHREAD_MUTEX_ROBUST or PTHREAD_MUTEX_STALLED. The |
| * default value is PTHREAD_MUTEX_STALLED . |
| * ■ PTHREAD_MUTEX_STALLED |
| * When the owner of the mutex terminates without unlocking the mutex, all subsequent calls |
| * to pthread_mutex_lock() are blocked from progress in an unspecified manner. |
| * ■ PTHREAD_MUTEX_ROBUST |
| * When the owner of the mutex terminates without unlocking the mutex, the mutex is |
| * unlocked. The next owner of this mutex acquires the mutex with an error return of |
| * EOWNERDEAD. |
| * Note – Your application must always check the return code from pthread_mutex_lock() for |
| * a mutex initialized with the PTHREAD_MUTEX_ROBUST attribute. |
| * ■ The new owner of this mutex should make the state protected by the mutex consistent. |
| * This state might have been left inconsistent when the previous owner terminated. |
| * ■ If the new owner is able to make the state consistent, call |
| * pthread_mutex_consistent() for the mutex before unlocking the mutex. This |
| * marks the mutex as consistent and subsequent calls to pthread_mutex_lock() and |
| * pthread_mutex_unlock() will behave in the normal manner. |
| * ■ If the new owner is not able to make the state consistent, do not call |
| * pthread_mutex_consistent() for the mutex, but unlock the mutex. |
| * All waiters are woken up and all subsequent calls to pthread_mutex_lock() fail to |
| * acquire the mutex. The return code is ENOTRECOVERABLE. The mutex can be made |
| * consistent by calling pthread_mutex_destroy() to uninitialize the mutex, and calling |
| * pthread_mutex_int() to reinitialize the mutex.However, the state that was protected |
| * by the mutex remains inconsistent and some form of application recovery is required. |
| * ■ If the thread that acquires the lock with EOWNERDEAD terminates without unlocking the |
| * mutex, the next owner acquires the lock with an EOWNERDEAD return code. |
| */ |
| #if !defined(_UWIN) |
| /*# include <process.h> */ |
| #endif |
| #include "pthread.h" |
| #include "implement.h" |
| |
| INLINE |
| int |
| ptw32_robust_mutex_inherit(pthread_mutex_t * mutex) |
| { |
| int result; |
| pthread_mutex_t mx = *mutex; |
| ptw32_robust_node_t* robust = mx->robustNode; |
| |
| switch ((LONG)PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG( |
| (PTW32_INTERLOCKED_LONGPTR)&robust->stateInconsistent, |
| (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_INCONSISTENT, |
| (PTW32_INTERLOCKED_LONG)-1 /* The terminating thread sets this */)) |
| { |
| case -1L: |
| result = EOWNERDEAD; |
| break; |
| case (LONG)PTW32_ROBUST_NOTRECOVERABLE: |
| result = ENOTRECOVERABLE; |
| break; |
| default: |
| result = 0; |
| break; |
| } |
| |
| return result; |
| } |
| |
| /* |
| * The next two internal support functions depend on only being |
| * called by the thread that owns the robust mutex. This enables |
| * us to avoid additional locks. |
| * Any mutex currently in the thread's robust mutex list is held |
| * by the thread, again eliminating the need for locks. |
| * The forward/backward links allow the thread to unlock mutexes |
| * in any order, not necessarily the reverse locking order. |
| * This is all possible because it is an error if a thread that |
| * does not own the [robust] mutex attempts to unlock it. |
| */ |
| |
| INLINE |
| void |
| ptw32_robust_mutex_add(pthread_mutex_t* mutex, pthread_t self) |
| { |
| ptw32_robust_node_t** list; |
| pthread_mutex_t mx = *mutex; |
| ptw32_thread_t* tp = (ptw32_thread_t*)self.p; |
| ptw32_robust_node_t* robust = mx->robustNode; |
| |
| list = &tp->robustMxList; |
| mx->ownerThread = self; |
| if (NULL == *list) |
| { |
| robust->prev = NULL; |
| robust->next = NULL; |
| *list = robust; |
| } |
| else |
| { |
| robust->prev = NULL; |
| robust->next = *list; |
| (*list)->prev = robust; |
| *list = robust; |
| } |
| } |
| |
| INLINE |
| void |
| ptw32_robust_mutex_remove(pthread_mutex_t* mutex, ptw32_thread_t* otp) |
| { |
| ptw32_robust_node_t** list; |
| pthread_mutex_t mx = *mutex; |
| ptw32_robust_node_t* robust = mx->robustNode; |
| |
| list = &(((ptw32_thread_t*)mx->ownerThread.p)->robustMxList); |
| mx->ownerThread.p = otp; |
| if (robust->next != NULL) |
| { |
| robust->next->prev = robust->prev; |
| } |
| if (robust->prev != NULL) |
| { |
| robust->prev->next = robust->next; |
| } |
| if (*list == robust) |
| { |
| *list = robust->next; |
| } |
| } |
| |
| |
| int |
| pthread_mutex_consistent (pthread_mutex_t* mutex) |
| { |
| pthread_mutex_t mx = *mutex; |
| int result = 0; |
| |
| /* |
| * Let the system deal with invalid pointers. |
| */ |
| if (mx == NULL) |
| { |
| return EINVAL; |
| } |
| |
| if (mx->kind >= 0 |
| || (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_INCONSISTENT != PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG( |
| (PTW32_INTERLOCKED_LONGPTR)&mx->robustNode->stateInconsistent, |
| (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_CONSISTENT, |
| (PTW32_INTERLOCKED_LONG)PTW32_ROBUST_INCONSISTENT)) |
| { |
| result = EINVAL; |
| } |
| |
| return (result); |
| } |
| |