From: NeilBrown <neilb@suse.de>
Date: Fri, 27 Dec 2019 04:45:53 +0000 (+1100)
Subject: vpatch: guard against patch list being empty.
X-Git-Tag: v1.2~6
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=987dc1497f7a6530b053270c8e4644c75e862ca5;p=wiggle.git

vpatch: guard against patch list being empty.

Mostly and empty list works, but get_prev() can
mess up - so fix it.

Signed-off-by: NeilBrown <neil@brown.name>
---

diff --git a/vpatch.c b/vpatch.c
index 9c37562..a1aa035 100644
--- a/vpatch.c
+++ b/vpatch.c
@@ -2427,7 +2427,7 @@ static void calc_one(struct plist *pl, FILE *f, int reverse,
 static int get_prev(int pos, struct plist *pl, int n, int mode)
 {
 	int found = 0;
-	if (pos == -1)
+	if (pos == -1 || pl == NULL)
 		return pos;
 	do {
 		if (pl[pos].prev == -1)