Robust mutexes merged from devel branchpost_merge_with_ROBUST_MUTEXES

1 files changed, 190 insertions, 0 deletions

diff --git a/pthread_mutex_consistent.c b/pthread_mutex_consistent.c
new file mode 100755
index 0000000..b5dcc15
--- /dev/null
+++ b/pthread_mutex_consistent.c
@@ -0,0 +1,190 @@
+/*
+ * 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.
+ */
+#ifndef _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 (PTW32_INTERLOCKED_COMPARE_EXCHANGE(
+            (LPLONG)&robust->stateInconsistent,
+            (LONG)PTW32_ROBUST_INCONSISTENT,
+            -1L /* 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
+        || (LONG)PTW32_ROBUST_INCONSISTENT != PTW32_INTERLOCKED_COMPARE_EXCHANGE(
+                                                (LPLONG)&mx->robustNode->stateInconsistent,
+                                                (LONG)PTW32_ROBUST_CONSISTENT,
+                                                (LONG)PTW32_ROBUST_INCONSISTENT))
+    {
+      result = EINVAL;
+    }
+
+  return (result);
+}
+