* exceptions.cc (ctrl_c_handler): Don't send SIGHUP on

CTRL_LOGOFF_EVENT to processes running in invisible Windows Stations.
	* window.cc (has_visible_window_station): New function.
	* winsup.h: Add declaration for has_visible_window_station.

winsup/cygwin/window.cc

@@ -247,3 +247,23 @@ ualarm (useconds_t value, useconds_t interval)
   return (otimer.it_value.tv_sec * 1000000) + otimer.it_value.tv_usec;
 }
 
+bool
+has_visible_window_station (void)
+{
+  HWINSTA station_hdl;
+  USEROBJECTFLAGS uof;
+  DWORD len;
+
+  /* Check if the process is associated with a visible window station.
+     These are processes running on the local desktop as well as processes
+     running in terminal server sessions.
+     Processes running in a service session not explicitely associated
+     with the desktop (using the "Allow service to interact with desktop"
+     property) are running in an invisible window station. */
+  if ((station_hdl = GetProcessWindowStation ())
+      && GetUserObjectInformationA (station_hdl, UOI_FLAGS, &uof,
+				    sizeof uof, &len)
+      && (uof.dwFlags & WSF_VISIBLE))
+    return true;
+  return false;
+}