From 8121b606e843c001d5ca5213d24099e04ebc62ca Mon Sep 17 00:00:00 2001
From: Takashi Yano via Cygwin-patches <cygwin-patches@cygwin.com>
Date: Tue, 30 Jun 2020 20:12:13 +0900
Subject: [PATCH] Cygwin: pty: Discard CSI > Pm m sequence from native windows
 apps.

- If vim is started from WSL (Ubuntu) which is executed in pseudo
  console in mintty, shift key and ctrl key do not work. Though
  this issue is similar to the issue resolved by commit
  4527541ec66af8d82bb9dba5d25afdf489d71271, that commit is not
  effective for this issue. This patch fixes the issue by discarding
  "CSI > Pm m" in fhandler_pty_master::pty_master_fwd_thread().
---
 winsup/cygwin/fhandler_tty.cc | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index 126249d9f..0f95cec2e 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -3316,6 +3316,34 @@ fhandler_pty_master::pty_master_fwd_thread ()
 		continue;
 	      }
 
+	  /* Remove CSI > Pm m */
+	  state = 0;
+	  start_at = 0;
+	  for (DWORD i=0; i<rlen; i++)
+	    if (outbuf[i] == '\033')
+	      {
+		start_at = i;
+		state = 1;
+		continue;
+	      }
+	    else if ((state == 1 && outbuf[i] == '[') ||
+		     (state == 2 && outbuf[i] == '>'))
+	      {
+		state ++;
+		continue;
+	      }
+	    else if (state == 3 && (isdigit (outbuf[i]) || outbuf[i] == ';'))
+	      continue;
+	    else if (state == 3 && outbuf[i] == 'm')
+	      {
+		memmove (&outbuf[start_at], &outbuf[i+1], rlen-i-1);
+		rlen = wlen = start_at + rlen - i - 1;
+		state = 0;
+		continue;
+	      }
+	    else
+	      state = 0;
+
 	  size_t nlen;
 	  char *buf = convert_mb_str
 	    (get_ttyp ()->term_code_page, &nlen, CP_UTF8, ptr, wlen);