commit 528d39b011afb7ef6fd794ba6b74155d4e69bc68
from: NRK <nrk@disroot.org>
via: Hiltjo Posthuma <hiltjo@codemadness.org>
date: Fri Sep  2 11:00:48 2022 UTC

tab-complete: figure out the size before copying

we already need to know the string length since `cursor` needs to be
adjusted.

so just calculate the length beforehand and use `memcpy` to copy exactly
as much as needed (as opposed to `strncpy` which always writes `n`
bytes).

commit - 32db2b125190d366be472ccb7cad833248696144
commit + 528d39b011afb7ef6fd794ba6b74155d4e69bc68
blob - 969f6d80622579da4b69dd65893aba7869b3d2b1
blob + 6b285df1cc5e66febdabc4f4997db298737ce419
--- dmenu.c
+++ dmenu.c
@@ -517,9 +517,9 @@ insert:
 	case XK_Tab:
 		if (!sel)
 			return;
-		strncpy(text, sel->text, sizeof text - 1);
+		cursor = strnlen(sel->text, sizeof text - 1);
+		memcpy(text, sel->text, cursor);
 		text[sizeof text - 1] = '\0';
-		cursor = strlen(text);
 		match();
 		break;
 	}