Corrected implementation of timed wait on condition variables. First

the timeout is given as a wall-time not an interval as was previously
implemented.  Second, the interpretation of ETIMEDOUT behavior was
incorrect as all possible error cases needed to be checked before
this error was returned.  This caused problems when the wall-time
specified was in the past.

2 files changed, 104 insertions, 58 deletions

diff --git a/c/src/exec/posix/src/cond.c b/c/src/exec/posix/src/cond.c
index e9ff4711dc..c480422f19 100644
--- a/c/src/exec/posix/src/cond.c
+++ b/c/src/exec/posix/src/cond.c
@@ -363,12 +363,14 @@ int pthread_cond_broadcast(
 int _POSIX_Condition_variables_Wait_support(
   pthread_cond_t            *cond,
   pthread_mutex_t           *mutex,
-  Watchdog_Interval          timeout
+  Watchdog_Interval          timeout,
+  boolean                    already_timedout
 )
 {
   register POSIX_Condition_variables_Control *the_cond;
   Objects_Locations                           location;
   int                                         status;
+  int                                         mutex_status;
  
   if ( !_POSIX_Mutex_Get( mutex, &location ) ) {
      return EINVAL;
@@ -391,38 +393,44 @@ int _POSIX_Condition_variables_Wait_support(
         return EINVAL;
       }
  
-      the_cond->Mutex = *mutex;
- 
-      status = pthread_mutex_unlock( mutex );
-/* XXX ignore this for now 
-      if ( status ) {
+      (void) pthread_mutex_unlock( mutex );
+/* XXX ignore this for now  since behavior is undefined
+      if ( mutex_status ) {
         _Thread_Enable_dispatch();
         return EINVAL;
       }
 */
+
+      if ( !already_timedout ) {
+        the_cond->Mutex = *mutex;
  
-      _Thread_queue_Enter_critical_section( &the_cond->Wait_queue );
-      _Thread_Executing->Wait.return_code = 0;
-      _Thread_Executing->Wait.queue       = &the_cond->Wait_queue;
-      _Thread_Executing->Wait.id          = *cond;
+        _Thread_queue_Enter_critical_section( &the_cond->Wait_queue );
+        _Thread_Executing->Wait.return_code = 0;
+        _Thread_Executing->Wait.queue       = &the_cond->Wait_queue;
+        _Thread_Executing->Wait.id          = *cond;
 
-      _Thread_queue_Enqueue( &the_cond->Wait_queue, timeout );
+        _Thread_queue_Enqueue( &the_cond->Wait_queue, timeout );
 
-      _Thread_Enable_dispatch();
+        _Thread_Enable_dispatch();
 
-      /*
-       *  Switch ourself out because we blocked as a result of the 
-       *  _Thread_queue_Enqueue.
-       */
+        /*
+         *  Switch ourself out because we blocked as a result of the 
+         *  _Thread_queue_Enqueue.
+         */
 
-      if ( _Thread_Executing->Wait.return_code )
-        return _Thread_Executing->Wait.return_code;
+        status = _Thread_Executing->Wait.return_code;
+        if ( status && status != ETIMEDOUT )
+          return status;
 
-      status = pthread_mutex_lock( mutex );
-      if ( status )
+      }
+      else
+        status = ETIMEDOUT;
+
+      mutex_status = pthread_mutex_lock( mutex );
+      if ( mutex_status )
         return EINVAL;
     
-      return _Thread_Executing->Wait.return_code;
+      return status;
   }
   return POSIX_BOTTOM_REACHED();
 }
@@ -440,7 +448,8 @@ int pthread_cond_wait(
   return _POSIX_Condition_variables_Wait_support(
     cond,
     mutex,
-    THREAD_QUEUE_WAIT_FOREVER
+    THREAD_QUEUE_WAIT_FOREVER,
+    FALSE
   );
 }
  
@@ -455,20 +464,34 @@ int pthread_cond_timedwait(
   const struct timespec *abstime
 )
 {
+  Watchdog_Interval timeout;
+  struct timespec   current_time;
+  struct timespec   difference;
+  boolean           already_timedout = FALSE;
+
   if ( !abstime )
     return EINVAL;
 
-/* XXX need to fully address an error occuring in the total timespec */
+  /*
+   *  The abstime is a walltime.  We turn it into an interval.
+   */
 
-  if ( abstime->tv_sec < 0 || abstime->tv_nsec < 0 )
-    return EINVAL;
+  (void) clock_gettime( CLOCK_REALTIME, &current_time );
+
+  /* XXX probably some error checking should go here */
+
+  _POSIX_Timespec_subtract( &current_time, abstime, &difference );
+
+  if ( ( difference.tv_sec < 0 ) || ( ( difference.tv_sec == 0 ) &&
+       ( difference.tv_nsec < 0 ) ) )
+    already_timedout = TRUE;   
+
+  timeout = _POSIX_Timespec_to_interval( &difference );
 
-  if ( abstime->tv_nsec >= TOD_NANOSECONDS_PER_SECOND )
-    return EINVAL;
- 
   return _POSIX_Condition_variables_Wait_support(
     cond,
     mutex,
-    _POSIX_Timespec_to_interval( abstime )
+    timeout,
+    already_timedout
   );
 }
diff --git a/cpukit/posix/src/cond.c b/cpukit/posix/src/cond.c
index e9ff4711dc..c480422f19 100644
--- a/cpukit/posix/src/cond.c
+++ b/cpukit/posix/src/cond.c
@@ -363,12 +363,14 @@ int pthread_cond_broadcast(
 int _POSIX_Condition_variables_Wait_support(
   pthread_cond_t            *cond,
   pthread_mutex_t           *mutex,
-  Watchdog_Interval          timeout
+  Watchdog_Interval          timeout,
+  boolean                    already_timedout
 )
 {
   register POSIX_Condition_variables_Control *the_cond;
   Objects_Locations                           location;
   int                                         status;
+  int                                         mutex_status;
  
   if ( !_POSIX_Mutex_Get( mutex, &location ) ) {
      return EINVAL;
@@ -391,38 +393,44 @@ int _POSIX_Condition_variables_Wait_support(
         return EINVAL;
       }
  
-      the_cond->Mutex = *mutex;
- 
-      status = pthread_mutex_unlock( mutex );
-/* XXX ignore this for now 
-      if ( status ) {
+      (void) pthread_mutex_unlock( mutex );
+/* XXX ignore this for now  since behavior is undefined
+      if ( mutex_status ) {
         _Thread_Enable_dispatch();
         return EINVAL;
       }
 */
+
+      if ( !already_timedout ) {
+        the_cond->Mutex = *mutex;
  
-      _Thread_queue_Enter_critical_section( &the_cond->Wait_queue );
-      _Thread_Executing->Wait.return_code = 0;
-      _Thread_Executing->Wait.queue       = &the_cond->Wait_queue;
-      _Thread_Executing->Wait.id          = *cond;
+        _Thread_queue_Enter_critical_section( &the_cond->Wait_queue );
+        _Thread_Executing->Wait.return_code = 0;
+        _Thread_Executing->Wait.queue       = &the_cond->Wait_queue;
+        _Thread_Executing->Wait.id          = *cond;
 
-      _Thread_queue_Enqueue( &the_cond->Wait_queue, timeout );
+        _Thread_queue_Enqueue( &the_cond->Wait_queue, timeout );
 
-      _Thread_Enable_dispatch();
+        _Thread_Enable_dispatch();
 
-      /*
-       *  Switch ourself out because we blocked as a result of the 
-       *  _Thread_queue_Enqueue.
-       */
+        /*
+         *  Switch ourself out because we blocked as a result of the 
+         *  _Thread_queue_Enqueue.
+         */
 
-      if ( _Thread_Executing->Wait.return_code )
-        return _Thread_Executing->Wait.return_code;
+        status = _Thread_Executing->Wait.return_code;
+        if ( status && status != ETIMEDOUT )
+          return status;
 
-      status = pthread_mutex_lock( mutex );
-      if ( status )
+      }
+      else
+        status = ETIMEDOUT;
+
+      mutex_status = pthread_mutex_lock( mutex );
+      if ( mutex_status )
         return EINVAL;
     
-      return _Thread_Executing->Wait.return_code;
+      return status;
   }
   return POSIX_BOTTOM_REACHED();
 }
@@ -440,7 +448,8 @@ int pthread_cond_wait(
   return _POSIX_Condition_variables_Wait_support(
     cond,
     mutex,
-    THREAD_QUEUE_WAIT_FOREVER
+    THREAD_QUEUE_WAIT_FOREVER,
+    FALSE
   );
 }
  
@@ -455,20 +464,34 @@ int pthread_cond_timedwait(
   const struct timespec *abstime
 )
 {
+  Watchdog_Interval timeout;
+  struct timespec   current_time;
+  struct timespec   difference;
+  boolean           already_timedout = FALSE;
+
   if ( !abstime )
     return EINVAL;
 
-/* XXX need to fully address an error occuring in the total timespec */
+  /*
+   *  The abstime is a walltime.  We turn it into an interval.
+   */
 
-  if ( abstime->tv_sec < 0 || abstime->tv_nsec < 0 )
-    return EINVAL;
+  (void) clock_gettime( CLOCK_REALTIME, &current_time );
+
+  /* XXX probably some error checking should go here */
+
+  _POSIX_Timespec_subtract( &current_time, abstime, &difference );
+
+  if ( ( difference.tv_sec < 0 ) || ( ( difference.tv_sec == 0 ) &&
+       ( difference.tv_nsec < 0 ) ) )
+    already_timedout = TRUE;   
+
+  timeout = _POSIX_Timespec_to_interval( &difference );
 
-  if ( abstime->tv_nsec >= TOD_NANOSECONDS_PER_SECOND )
-    return EINVAL;
- 
   return _POSIX_Condition_variables_Wait_support(
     cond,
     mutex,
-    _POSIX_Timespec_to_interval( abstime )
+    timeout,
+    already_timedout
   );
 }