From: Martin Hostettler <textshell@uchuujin.de>
Date: Sat, 15 Dec 2018 14:34:21 +0000 (+0100)
Subject: vt: Implement parsing for >, =, < private sequences.
X-Git-Tag: v5.1-rc1~143^2~40
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5445447b62e0cf69a6f8b62df51c1ef6f2cd56fe;p=thirdparty%2Flinux.git

vt: Implement parsing for >, =, < private sequences.

Private sequences can start with '>', '=' and (in theory) '<'.
Implement correct parsing for these. The newly parsable sequences are
cleanly ignored as it is customary with terminal emulators.

This allows the vt to ignore various sequences used by more capable
terminal implementations such as "Secondary Device Attributes",
"Tertiary Device Attributes" and various advanced configuration commands
that don't have dedicated terminfo entries.

Signed-off-by: Martin Hostettler <textshell@uchuujin.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index b59feeaaf02b2..ec61f83562456 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2236,9 +2236,21 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			vc->vc_state=ESfunckey;
 			return;
 		}
-		vc->vc_priv = (c == '?') ? EPdec : EPecma;
-		if (vc->vc_priv != EPecma)
+		switch (c) {
+		case '?':
+			vc->vc_priv = EPdec;
+			return;
+		case '>':
+			vc->vc_priv = EPgt;
+			return;
+		case '=':
+			vc->vc_priv = EPeq;
 			return;
+		case '<':
+			vc->vc_priv = EPlt;
+			return;
+		}
+		vc->vc_priv = EPecma;
 		/* fall through */
 	case ESgetpars:
 		if (c == ';' && vc->vc_npar < NPAR - 1) {
@@ -2252,10 +2264,12 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 		vc->vc_state = ESnormal;
 		switch(c) {
 		case 'h':
-			set_mode(vc, 1);
+			if (vc->vc_priv <= EPdec)
+				set_mode(vc, 1);
 			return;
 		case 'l':
-			set_mode(vc, 0);
+			if (vc->vc_priv <= EPdec)
+				set_mode(vc, 0);
 			return;
 		case 'c':
 			if (vc->vc_priv == EPdec) {