From 835c9df64b90dd08282766c73b1374fbc4132d97 Mon Sep 17 00:00:00 2001
From: Vincent Bernat <vincent.bernat@dailymotion.com>
Date: Fri, 11 Jan 2013 18:53:10 +0100
Subject: [PATCH] compat: add `strnlen()` which may be absent on some older
 systems

---
 configure.ac         |  2 +-
 src/compat/compat.h  |  4 ++++
 src/compat/strnlen.c | 14 ++++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 src/compat/strnlen.c

diff --git a/configure.ac b/configure.ac
index 8d494fc3..1e86355e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -93,7 +93,7 @@ lldp_CHECK___PROGNAME
 AC_CONFIG_LIBOBJ_DIR([src/compat])
 AC_FUNC_MALLOC
 AC_FUNC_REALLOC
-AC_REPLACE_FUNCS([strlcpy])
+AC_REPLACE_FUNCS([strlcpy strnlen])
 AC_CHECK_FUNCS([setresuid setresgid])
 
 AC_SEARCH_LIBS([__res_init], resolv bind, AC_DEFINE([HAVE_RES_INIT], 1, [Define to indicate that res_init() exists]),
diff --git a/src/compat/compat.h b/src/compat/compat.h
index 9f432866..0374a4ef 100644
--- a/src/compat/compat.h
+++ b/src/compat/compat.h
@@ -39,6 +39,10 @@
 size_t	strlcpy(char *, const char *, size_t);
 #endif
 
+#if !HAVE_STRNLEN
+size_t	strnlen(const char *, size_t);
+#endif
+
 #if !HAVE_MALLOC
 void *malloc(size_t size);
 #endif
diff --git a/src/compat/strnlen.c b/src/compat/strnlen.c
new file mode 100644
index 00000000..8bc3525c
--- /dev/null
+++ b/src/compat/strnlen.c
@@ -0,0 +1,14 @@
+/* -*- mode: c; c-file-style: "openbsd" -*- */
+
+#include <string.h>
+
+/*
+ * Determine the length of a fixed-size string. This is really a
+ * wrapper around `memchr()`.
+ */
+size_t
+strnlen(const char *string, size_t maxlen)
+{
+	const char *end = memchr(string, '\0', maxlen);
+	return end?(size_t)(end - string):maxlen;
+}
-- 
2.39.2