[newlib-cygwin/cygwin-3_3-branch] Cygwin: console: Fix interference issue regarding master thread.

[Takashi Yano <tyan0@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=f9f06a4607adb9dfcc4fbf88ed2ba0653943677d

commit f9f06a4607adb9dfcc4fbf88ed2ba0653943677d
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Thu Nov 18 12:28:53 2021 +0900

    Cygwin: console: Fix interference issue regarding master thread.
    
    - This patch fixes the issue that ReadConsoleInputW() call in the
      master thread interferes with the input process of non-cygwin apps.

Diff:
---
 winsup/cygwin/fhandler.h          |  1 +
 winsup/cygwin/fhandler_console.cc | 11 +++++++++++
 2 files changed, 12 insertions(+)

diff --git a/winsup/cygwin/fhandler.h b/winsup/cygwin/fhandler.h
index c033f7816..f9baff852 100644
--- a/winsup/cygwin/fhandler.h
+++ b/winsup/cygwin/fhandler.h
@@ -2042,6 +2042,7 @@ class dev_console
   char cons_rabuf[40];  // cannot get longer than char buf[40] in char_command
   char *cons_rapoi;
   bool cursor_key_app_mode;
+  bool disable_master_thread;
 
   inline UINT get_console_cp ();
   DWORD con_to_str (char *d, int dlen, WCHAR w);
diff --git a/winsup/cygwin/fhandler_console.cc b/winsup/cygwin/fhandler_console.cc
index a7e9723bd..4b7922dea 100644
--- a/winsup/cygwin/fhandler_console.cc
+++ b/winsup/cygwin/fhandler_console.cc
@@ -208,6 +208,12 @@ fhandler_console::cons_master_thread (handle_set_t *p, tty *ttyp)
       DWORD total_read, n, i;
       INPUT_RECORD input_rec[INREC_SIZE];
 
+      if (con.disable_master_thread)
+	{
+	  cygwait (40);
+	  continue;
+	}
+
       WaitForSingleObject (p->input_mutex, INFINITE);
       total_read = 0;
       switch (cygwait (p->input_handle, (DWORD) 0))
@@ -427,6 +433,7 @@ fhandler_console::setup ()
       con.cons_rapoi = NULL;
       shared_console_info->tty_min_state.is_console = true;
       con.cursor_key_app_mode = false;
+      con.disable_master_thread = false;
     }
 }
 
@@ -480,6 +487,8 @@ fhandler_console::set_input_mode (tty::cons_mode m, const termios *t,
 	flags |= ENABLE_VIRTUAL_TERMINAL_INPUT;
       else
 	flags |= ENABLE_MOUSE_INPUT;
+      if (shared_console_info)
+	con.disable_master_thread = false;
       break;
     case tty::native:
       if (t->c_lflag & ECHO)
@@ -492,6 +501,8 @@ fhandler_console::set_input_mode (tty::cons_mode m, const termios *t,
 	flags &= ~ENABLE_ECHO_INPUT;
       if (t->c_lflag & ISIG)
 	flags |= ENABLE_PROCESSED_INPUT;
+      if (shared_console_info)
+	con.disable_master_thread = true;
       break;
     }
   SetConsoleMode (p->input_handle, flags);