* 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, 14 insertions, 0 deletions

diff --git a/winsup/cygwin/ntdll.h b/winsup/cygwin/ntdll.h
index 2582bf25f..c67a775ec 100644
--- a/winsup/cygwin/ntdll.h
+++ b/winsup/cygwin/ntdll.h
@@ -1102,6 +1102,18 @@ typedef enum _EVENT_INFORMATION_CLASS
   EventBasicInformation = 0
 } EVENT_INFORMATION_CLASS, *PEVENT_INFORMATION_CLASS;
 
+/* Checked on 64 bit. */
+typedef struct _SEMAPHORE_BASIC_INFORMATION
+{
+  LONG CurrentCount;
+  LONG MaximumCount;
+} SEMAPHORE_BASIC_INFORMATION, *PSEMAPHORE_BASIC_INFORMATION;
+
+typedef enum _SEMAPHORE_INFORMATION_CLASS
+{
+  SemaphoreBasicInformation = 0
+} SEMAPHORE_INFORMATION_CLASS, *PSEMAPHORE_INFORMATION_CLASS;
+
 typedef enum _THREAD_INFORMATION_CLASS
 {
   ThreadBasicInformation = 0,
@@ -1275,6 +1287,8 @@ extern "C"
 					  PVOID, ULONG, PULONG);
   NTSTATUS NTAPI NtQueryObject (HANDLE, OBJECT_INFORMATION_CLASS, VOID *,
 				ULONG, ULONG *);
+  NTSTATUS NTAPI NtQuerySemaphore (HANDLE, SEMAPHORE_INFORMATION_CLASS,
+				   PVOID, ULONG, PULONG);
   NTSTATUS NTAPI NtQuerySystemInformation (SYSTEM_INFORMATION_CLASS,
 					   PVOID, ULONG, PULONG);
   NTSTATUS WINAPI NtQuerySystemTime (PLARGE_INTEGER);