Cygwin: pthread_cond_wait: Do as Linux and BSD do.

POSIX states as follows about pthread_cond_wait:
If a signal is delivered to a thread waiting for a condition variable,
upon return from the signal handler the thread resumes waiting for the
condition variable as if it was not interrupted, or it returns zero
due to spurious wakeup.

Cygwin so far employs the latter behaviour, while Linux and BSD employ
the former one.

Align Cygwin behaviour to Linux and BSD.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index 7084657e0f2d0104ebde7ecab58911af3d10707b..8cae82cfeeb56b388a2795b4c2a4c95533189db4 100644 (file)
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -1266,24 +1266,14 @@ pthread_cond::wait (pthread_mutex_t mutex, PLARGE_INTEGER timeout)
   ++mutex->condwaits;
   mutex->unlock ();
 
-  rv = cygwait (sem_wait, timeout, cw_cancel | cw_sig_eintr);
+  rv = cygwait (sem_wait, timeout, cw_cancel | cw_sig_restart);
 
   mtx_out.lock ();
 
-  if (rv != WAIT_OBJECT_0)
-    {
-      /*
-       * It might happen that a signal is sent while the thread got canceled
-       * or timed out. Try to take one.
-       * If the thread gets one than a signal|broadcast is in progress.
-       */
-      if (WaitForSingleObject (sem_wait, 0) == WAIT_OBJECT_0)
-       /*
-        * thread got cancelled ot timed out while a signalling is in progress.
-        * Set wait result back to signaled
-        */
-       rv = WAIT_OBJECT_0;
-    }
+  if (rv != WAIT_OBJECT_0 && WaitForSingleObject (sem_wait, 0) == WAIT_OBJECT_0)
+    /* Thread got cancelled ot timed out while a signalling is in progress.
+       Set wait result back to signaled */
+    rv = WAIT_OBJECT_0;
 
   InterlockedDecrement (&waiting);
 
@@ -1301,13 +1291,6 @@ pthread_cond::wait (pthread_mutex_t mutex, PLARGE_INTEGER timeout)
 
   if (rv == WAIT_CANCELED)
     pthread::static_cancel_self ();
-  else if (rv == WAIT_SIGNALED)
-    /* SUSv3 states:  If a signal is delivered to a thread waiting for a
-       condition variable, upon return from the signal handler the thread
-       resumes waiting for the condition variable as if it was not
-       interrupted, or it shall return zero due to spurious wakeup.
-       We opt for the latter choice here. */
-    return 0;
   else if (rv == WAIT_TIMEOUT)
     return ETIMEDOUT;