From 42faed412857d4a0069d982d5c8cfe138b7a0197 Mon Sep 17 00:00:00 2001
From: Corinna Vinschen <corinna@vinschen.de>
Date: Sat, 30 Apr 2011 10:20:25 +0000
Subject: [PATCH] 	* thread.h (class pthread): Add bool member canceled. 
 * thread.cc (pthread::pthread): Initialize canceled to false. 
 (pthread::cancel): Set canceled before setting cancel_event. 
 (pthread::testcancel): Check for canceled.  Only wait for cancel_event 
 if canceled is true.  Explain why. 	(pthread::_fixup_after_fork): Set
 canceled to false.

---
 winsup/cygwin/ChangeLog |  9 +++++++++
 winsup/cygwin/thread.cc | 16 +++++++++++++---
 winsup/cygwin/thread.h  |  1 +
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 08d5533e4..5b0d8ae7b 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,12 @@
+2011-04-30  Corinna Vinschen  <corinna@vinschen.de>
+
+	* thread.h (class pthread): Add bool member canceled.
+	* thread.cc (pthread::pthread): Initialize canceled to false.
+	(pthread::cancel): Set canceled before setting cancel_event.
+	(pthread::testcancel): Check for canceled.  Only wait for cancel_event
+	if canceled is true.  Explain why.
+	(pthread::_fixup_after_fork): Set canceled to false.
+
 2011-04-29  Corinna Vinschen  <corinna@vinschen.de>
 
 	* errno.cc (errmap): Sort.  Map ERROR_EXE_MACHINE_TYPE_MISMATCH to
diff --git a/winsup/cygwin/thread.cc b/winsup/cygwin/thread.cc
index a9e5f77c0..10fc2c66b 100644
--- a/winsup/cygwin/thread.cc
+++ b/winsup/cygwin/thread.cc
@@ -378,7 +378,7 @@ List<pthread> pthread::threads;
 
 /* member methods */
 pthread::pthread ():verifyable_object (PTHREAD_MAGIC), win32_obj_id (0),
-		    valid (false), suspended (false),
+		    valid (false), suspended (false), canceled (false),
 		    cancelstate (0), canceltype (0), cancel_event (0),
 		    joiner (NULL), next (NULL), cleanup_stack (NULL)
 {
@@ -538,6 +538,7 @@ pthread::cancel ()
     {
       // cancel deferred
       mutex.unlock ();
+      canceled = true;
       SetEvent (cancel_event);
       return 0;
     }
@@ -871,8 +872,16 @@ pthread::testcancel ()
   if (cancelstate == PTHREAD_CANCEL_DISABLE)
     return;
 
-  if (IsEventSignalled (cancel_event))
-    cancel_self ();
+  /* We check for the canceled flag first.  This allows to use the
+     pthread_testcancel function a lot without adding the overhead of
+     an OS call.  Only if the thread is marked as canceled, we wait for
+     cancel_event being really set, on the off-chance that pthread_cancel
+     gets interrupted before calling SetEvent. */
+  if (canceled)
+    {
+      WaitForSingleObject (cancel_event, INFINITE);
+      cancel_self ();
+    }
 }
 
 void
@@ -1039,6 +1048,7 @@ pthread::_fixup_after_fork ()
       magic = 0;
       valid = false;
       win32_obj_id = NULL;
+      canceled = false;
       cancel_event = NULL;
     }
 }
diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h
index f96714f49..2453630f8 100644
--- a/winsup/cygwin/thread.h
+++ b/winsup/cygwin/thread.h
@@ -366,6 +366,7 @@ public:
   void *return_ptr;
   bool valid;
   bool suspended;
+  bool canceled;
   int cancelstate, canceltype;
   _cygtls *cygtls;
   HANDLE cancel_event;
-- 
2.43.5