From: Keith Packard <keithp@keithp.com>
Date: Sun, 10 Dec 2017 08:02:34 +0000 (-0800)
Subject: altos/scheme: Avoid crashing with non-list in length
X-Git-Tag: 1.8.3~1^2~21^2
X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=commitdiff_plain;h=abb856cd66e00d739e4efb1930b5c168eaf48029

altos/scheme: Avoid crashing with non-list in length

Use ao_scheme_cons_cdr to fetch the next list element as that returns
NULL for non-cons elements.

Signed-off-by: Keith Packard <keithp@keithp.com>
---

diff --git a/src/scheme/ao_scheme_cons.c b/src/scheme/ao_scheme_cons.c
index 03dad956..21ee10cc 100644
--- a/src/scheme/ao_scheme_cons.c
+++ b/src/scheme/ao_scheme_cons.c
@@ -195,7 +195,7 @@ ao_scheme_cons_length(struct ao_scheme_cons *cons)
 	int	len = 0;
 	while (cons) {
 		len++;
-		cons = ao_scheme_poly_cons(cons->cdr);
+		cons = ao_scheme_cons_cdr(cons);
 	}
 	return len;
 }