From 7354ec8f2bd0e5b730170abd9eface9681720fd8 Mon Sep 17 00:00:00 2001
From: Vincent Bernat <bernat@luffy.cx>
Date: Sun, 23 Jun 2013 09:25:02 +0200
Subject: [PATCH] compat: add `strndup()` compatibility function

This function does not exist on OS X 10.6 for example. This was a long
time GNU extension.
---
 configure.ac         |  2 +-
 src/compat/compat.h  |  4 ++++
 src/compat/strndup.c | 22 ++++++++++++++++++++++
 3 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 src/compat/strndup.c

diff --git a/configure.ac b/configure.ac
index ce765756..ac71aac2 100644
--- a/configure.ac
+++ b/configure.ac
@@ -96,7 +96,7 @@ AC_CONFIG_LIBOBJ_DIR([src/compat])
 AC_FUNC_MALLOC
 AC_FUNC_REALLOC
 AC_SEARCH_LIBS([setproctitle], [util bsd])
-AC_REPLACE_FUNCS([strlcpy strnlen fgetln setproctitle])
+AC_REPLACE_FUNCS([strlcpy strnlen strndup fgetln setproctitle])
 AC_CHECK_FUNCS([setresuid setresgid])
 
 case " $LIBS " in
diff --git a/src/compat/compat.h b/src/compat/compat.h
index 8a72bf57..643a7828 100644
--- a/src/compat/compat.h
+++ b/src/compat/compat.h
@@ -49,6 +49,10 @@ size_t	strlcpy(char *, const char *, size_t);
 size_t	strnlen(const char *, size_t);
 #endif
 
+#if !HAVE_STRNDUP
+char	*strndup(const char *, size_t);
+#endif
+
 #if !HAVE_FGETLN
 char *fgetln(FILE *, size_t *);
 #endif
diff --git a/src/compat/strndup.c b/src/compat/strndup.c
new file mode 100644
index 00000000..f0f1f3e8
--- /dev/null
+++ b/src/compat/strndup.c
@@ -0,0 +1,22 @@
+/* -*- mode: c; c-file-style: "openbsd" -*- */
+
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * Similar to `strdup()` but copies at most n bytes.
+ */
+char*
+strndup(const char *string, size_t maxlen)
+{
+	char *result;
+	/* We may use `strnlen()` but it may be unavailable. */
+	const char *end = memchr(string, '\0', maxlen);
+	size_t len = end?(size_t)(end - string):maxlen;
+
+	result = malloc(len + 1);
+	if (!result) return 0;
+
+	memcpy(result, string, len);
+	return result;
+}
-- 
2.39.5