From: Rusty Russell <rusty@rustcorp.com.au>
Date: Mon, 9 Jan 2023 02:19:22 +0000 (+1030)
Subject: rbuf: avoid doing memchr(NULL, ..., 0).
X-Git-Url: http://git.ozlabs.org/?a=commitdiff_plain;h=d87a25dc5510f47ed876985f6014dbfa4a96f1aa;p=ccan

rbuf: avoid doing memchr(NULL, ..., 0).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/ccan/rbuf/rbuf.c b/ccan/rbuf/rbuf.c
index d8d658d3..cc10cf3d 100644
--- a/ccan/rbuf/rbuf.c
+++ b/ccan/rbuf/rbuf.c
@@ -74,9 +74,11 @@ char *rbuf_read_str(struct rbuf *rbuf, char term)
 	ssize_t r = 0;
 	size_t prev = 0;
 
-	while (!(p = memchr(membuf_elems(&rbuf->m) + prev,
-			    term,
-			    membuf_num_elems(&rbuf->m) - prev))) {
+	/* memchr(NULL, ..., 0) is illegal.  FML. */
+	while (membuf_num_elems(&rbuf->m) == prev
+	       || !(p = memchr(membuf_elems(&rbuf->m) + prev,
+			       term,
+			       membuf_num_elems(&rbuf->m) - prev))) {
 		prev += r;
 		r = get_more(rbuf);
 		if (r < 0)