Cygwin: pty: Fix failure to clear switch_to_nat_pipe flag.

After the commit fbfea31dd9, switch_to_nat_pipe is not cleared
properly when non-cygwin app is terminated in the case where the
pseudo console is disabled. This is because get_winpid_to_hand_over()
sometimes returns PID of cygwin process even though it should return
only PID of non-cygwin process. This patch fixes the issue by adding
a new argument which requests only PID of non-cygwin process to
get_console_process_id().

Fixes: fbfea31dd9 ("Cygwin: pty: Avoid cutting the branch the pty master is sitting on.")
Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>

winsup/cygwin/fhandler/pty.cc

@@ -85,7 +85,8 @@ inline static bool process_alive (DWORD pid);
      stub_only: return only stub process's pid of non-cygwin process. */
 DWORD
 fhandler_pty_common::get_console_process_id (DWORD pid, bool match,
-					     bool cygwin, bool stub_only)
+					     bool cygwin, bool stub_only,
+					     bool nat)
 {
   tmp_pathbuf tp;
   DWORD *list = (DWORD *) tp.c_get ();
@@ -109,6 +110,8 @@ fhandler_pty_common::get_console_process_id (DWORD pid, bool match,
 	else
 	  {
 	    pinfo p (cygwin_pid (list[i]));
+	    if (nat && !!p && !ISSTATE(p, PID_NOTCYGWIN))
+	      continue;
 	    if (!!p && p->exec_dwProcessId)
 	      {
 		res_pri = stub_only ? p->exec_dwProcessId : list[i];
@@ -3511,9 +3514,11 @@ fhandler_pty_slave::get_winpid_to_hand_over (tty *ttyp,
     {
       /* Search another native process which attaches to the same console */
       DWORD current_pid = myself->exec_dwProcessId ?: myself->dwProcessId;
-      switch_to = get_console_process_id (current_pid, false, true, true);
+      switch_to = get_console_process_id (current_pid,
+					  false, true, true, true);
       if (!switch_to)
-	switch_to = get_console_process_id (current_pid, false, true, false);
+	switch_to = get_console_process_id (current_pid,
+					    false, true, false, true);
     }
   return switch_to;
 }

winsup/cygwin/local_includes/fhandler.h

@@ -2399,7 +2399,8 @@ class fhandler_pty_common: public fhandler_termios
   void resize_pseudo_console (struct winsize *);
   static DWORD get_console_process_id (DWORD pid, bool match,
 				       bool cygwin = false,
-				       bool stub_only = false);
+				       bool stub_only = false,
+				       bool nat = false);
   bool to_be_read_from_nat_pipe (void);
   static DWORD attach_console_temporarily (DWORD target_pid);
   static void resume_from_temporarily_attach (DWORD resume_pid);

winsup/cygwin/release/3.4.9

@@ -0,0 +1,6 @@
+Bug Fixes
+---------
+
+- Fix a bug introduced in cygwin 3.4.0 that switch_to_nat_pipe flag is
+  not cleared properly when non-cygwin app is terminated in the case
+  where pseudo console is not activated.