[newlib-cygwin] Cygwin: pty: Fix handle leak regarding attach_mutex.

[Ken Brown <kbrown@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=dcd564f65caa96a9dc5c0d17020b9674a1a36e32

commit dcd564f65caa96a9dc5c0d17020b9674a1a36e32
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Sun Oct 10 09:49:53 2021 +0900

    Cygwin: pty: Fix handle leak regarding attach_mutex.
    
    - If the process having master pty opened is forked, attach_mutex
      fails to be closed when master is closed. This patch fixes the
      issue.

Diff:
---
 winsup/cygwin/fhandler_console.cc | 2 +-
 winsup/cygwin/fhandler_tty.cc     | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/winsup/cygwin/fhandler_console.cc b/winsup/cygwin/fhandler_console.cc
index ee862b17d..aee5e8284 100644
--- a/winsup/cygwin/fhandler_console.cc
+++ b/winsup/cygwin/fhandler_console.cc
@@ -57,7 +57,7 @@ fhandler_console::console_state NO_COPY *fhandler_console::shared_console_info;
 bool NO_COPY fhandler_console::invisible_console;
 
 /* Mutex for AttachConsole()/FreeConsole() in fhandler_tty.cc */
-HANDLE NO_COPY attach_mutex;
+HANDLE attach_mutex;
 
 static inline void
 acquire_attach_mutex (DWORD t)
diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index 823dabf73..f523dafed 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -57,7 +57,7 @@ struct pipe_reply {
 };
 
 extern HANDLE attach_mutex; /* Defined in fhandler_console.cc */
-static LONG NO_COPY master_cnt = 0;
+static LONG master_cnt = 0;
 
 inline static bool pcon_pid_alive (DWORD pid);
 
@@ -2042,10 +2042,10 @@ fhandler_pty_master::close ()
 	    }
 	  release_output_mutex ();
 	  master_fwd_thread->terminate_thread ();
-	  if (InterlockedDecrement (&master_cnt) == 0)
-	    CloseHandle (attach_mutex);
 	}
     }
+  if (InterlockedDecrement (&master_cnt) == 0)
+    CloseHandle (attach_mutex);
 
   /* Check if the last master handle has been closed.  If so, set
      input_available_event to wake up potentially waiting slaves. */