2 files changed, 23 insertions, 0 deletions
diff --git a/src/string_util.c b/src/string_util.c
index b76b257ba..5d9feccf9 100644
--- a/src/string_util.c
+++ b/src/string_util.c
@@ -48,6 +48,21 @@ string_array_contains(const char *const* haystack, const char *needle)
 	return false;
 }
 
+#ifndef HAVE_STRNLEN
+
+size_t
+strnlen(const char *s, size_t max)
+{
+	assert(s != NULL);
+
+	const char *t = memchr(s, 0, max);
+	return t != NULL
+		? (size_t)(t - s)
+		: max;
+}
+
+#endif
+
 #if !defined(HAVE_STRNDUP)
 
 char *
diff --git a/src/string_util.h b/src/string_util.h
index 374fd0f91..62de53873 100644
--- a/src/string_util.h
+++ b/src/string_util.h
@@ -83,6 +83,14 @@ strchug_fast(char *p)
 bool
 string_array_contains(const char *const* haystack, const char *needle);
 
+#ifndef HAVE_STRNLEN
+
+gcc_pure
+size_t
+strnlen(const char *s, size_t max);
+
+#endif
+
 #if !defined(HAVE_STRNDUP)
 
 /**