* ntdll.h (struct _SEMAPHORE_BASIC_INFORMATION): Define.

	(enum _SEMAPHORE_INFORMATION_CLASS): Define.
	(NtQuerySemaphore): Declare.
	* thread.h (class semaphore): Add member startvalue.
	(semaphore::fixup_before_fork): New inline method.
	(semaphore::_fixup_before_fork): Declare.
	* thread.cc (MTinterface::fixup_before_fork): Additionally call
	semaphore::fixup_before_fork.
	(semaphore::semaphore): Set currentvalue to -1.  Set startvalue to
	incoming initializer value.
	(semaphore::_getvalue): Just query semaphore using NtQuerySemaphore
	rather then using WFSO/Release.
	(semaphore::_post): Drop setting currentvalue.  It's not thread-safe.
	(semaphore::_trywait): Ditto.
	(semaphore::_timedwait): Ditto.
	(semaphore::_wait): Ditto.
	(semaphore::_fixup_before_fork): New method, setting currentvalue from
	actual windows semaphore right before fork.
	(semaphore::_fixup_after_fork): Drop kludge from 2013-07-10.  Drop
	FIXME comment.

1 files changed, 6 insertions, 0 deletions

diff --git a/winsup/cygwin/thread.h b/winsup/cygwin/thread.h
index c87c620eb..badffcb79 100644
--- a/winsup/cygwin/thread.h
+++ b/winsup/cygwin/thread.h
@@ -638,6 +638,7 @@ public:
   HANDLE win32_obj_id;
   int shared;
   LONG currentvalue;
+  LONG startvalue;
   int fd;
   unsigned long long hash;
   LUID luid;
@@ -648,6 +649,10 @@ public:
   ~semaphore ();
 
   class semaphore * next;
+  static void fixup_before_fork ()
+  {
+    semaphores.for_each (&semaphore::_fixup_before_fork);
+  }
   static void fixup_after_fork ()
   {
     semaphores.fixup_after_fork ();
@@ -666,6 +671,7 @@ private:
   int _trywait ();
   int _timedwait (const struct timespec *abstime);
 
+  void _fixup_before_fork ();
   void _fixup_after_fork ();
   void _terminate ();