st

commit f114bcedd113017d907aad32031db92c050f4bf3
parent 98610fcd37f655d44586323dc86c1d013c2798ce
Author: sasha <sasha.code@posteo.mx>
Date:   Sun, 27 Jul 2025 05:43:47 +0000

Eat up "CSI 58" sequences

This is used in the wild by systemd systemctl for example and st
misinterpreted it as "blink", because it didn't know "58", then saw "5"
as "blink", and then didn't know "245".

This should print "foo" as normal text:

    printf '\e[58:5:245mfoo\n'
    printf '\e[58:2:50:100:200mfoo\n'

Diffstat:
M
st.c
 | 
6
++++++

1 file changed, 6 insertions(+), 0 deletions(-)
diff --git a/st.c b/st.c
@@ -1430,6 +1430,12 @@ tsetattr(const int *attr, int l)
 		case 49:
 			term.c.attr.bg = defaultbg;
 			break;
+		case 58:
+			/* This starts a sequence to change the color of
+			 * "underline" pixels. We don't support that and
+			 * instead eat up a following "5;n" or "2;r;g;b". */
+			tdefcolor(attr, &i, l);
+			break;
 		default:
 			if (BETWEEN(attr[i], 30, 37)) {
 				term.c.attr.fg = attr[i] - 30;