Cygwin: pty: Revise the code to wait for completion of forwarding.

- With this patch, the code to wait for completion of forwarding of
  output from non-cygwin app is revised so that it can more reliably
  detect the completion.

3 files changed, 12 insertions, 7 deletions

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index 7e065c46a..7e733e49a 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -1118,7 +1118,7 @@ fhandler_pty_slave::reset_switch_to_pcon (void)
       if (WaitForSingleObject (h_gdb_process, 0) == WAIT_TIMEOUT)
 	{
 	  if (isHybrid)
-	    get_ttyp ()->wait_pcon_fwd (false);
+	    get_ttyp ()->wait_pcon_fwd ();
 	}
       else
 	{
@@ -2705,6 +2705,9 @@ fhandler_pty_master::pty_master_fwd_thread (const master_fwd_thread_param_t *p)
   for (;;)
     {
       p->ttyp->pcon_last_time = GetTickCount ();
+      DWORD n;
+      p->ttyp->pcon_fwd_not_empty =
+	::bytes_available (n, p->from_slave_nat) && n;
       if (!ReadFile (p->from_slave_nat, outbuf, NT_MAX_PATH, &rlen, NULL))
 	{
 	  termios_printf ("ReadFile for forwarding failed, %E");
diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc
index 789528856..da75b8dd2 100644
--- a/winsup/cygwin/tty.cc
+++ b/winsup/cygwin/tty.cc
@@ -240,6 +240,7 @@ tty::init ()
   pcon_pid = 0;
   term_code_page = 0;
   pcon_last_time = 0;
+  pcon_fwd_not_empty = false;
   pcon_start = false;
   pcon_start_pid = 0;
   pcon_cap_checked = false;
@@ -367,7 +368,7 @@ tty_min::setpgid (int pid)
 }
 
 void
-tty::wait_pcon_fwd (bool init)
+tty::wait_pcon_fwd ()
 {
   /* The forwarding in pseudo console sometimes stops for
      16-32 msec even if it already has data to transfer.
@@ -377,11 +378,11 @@ tty::wait_pcon_fwd (bool init)
      thread when the last data is transfered. */
   const int sleep_in_pcon = 16;
   const int time_to_wait = sleep_in_pcon * 2 + 1/* margine */;
-  if (init)
-    pcon_last_time = GetTickCount ();
-  while (GetTickCount () - pcon_last_time < time_to_wait)
+  int elapsed;
+  while (pcon_fwd_not_empty
+	 || (elapsed = GetTickCount () - pcon_last_time) < time_to_wait)
     {
-      int tw = time_to_wait - (GetTickCount () - pcon_last_time);
+      int tw = pcon_fwd_not_empty ? 10 : (time_to_wait - elapsed);
       cygwait (tw);
     }
 }
diff --git a/winsup/cygwin/tty.h b/winsup/cygwin/tty.h
index 519d7c0d5..2cd12a665 100644
--- a/winsup/cygwin/tty.h
+++ b/winsup/cygwin/tty.h
@@ -116,6 +116,7 @@ private:
   DWORD pcon_pid;
   UINT term_code_page;
   DWORD pcon_last_time;
+  bool pcon_fwd_not_empty;
   HANDLE h_pcon_write_pipe;
   HANDLE h_pcon_condrv_reference;
   HANDLE h_pcon_conhost_process;
@@ -166,7 +167,7 @@ public:
   void set_master_ctl_closed () {master_pid = -1;}
   static void __stdcall create_master (int);
   static void __stdcall init_session ();
-  void wait_pcon_fwd (bool init = true);
+  void wait_pcon_fwd ();
   bool pcon_input_state_eq (xfer_dir x) { return pcon_input_state == x; }
   bool pcon_fg (pid_t pgid);
   friend class fhandler_pty_common;