diff --git a/libbb/concat_path_file.c b/libbb/concat_path_file.c
index 61efa9c3e..c699a84f7 100644
--- a/libbb/concat_path_file.c
+++ b/libbb/concat_path_file.c
@@ -13,11 +13,14 @@ extern char *concat_path_file(const char *path, const char *filename)
 {
 	char *outbuf;
 	char *lc;
-	
+
+	if (!path)
+	    path="";
 	lc = last_char_is(path, '/');
 	if (filename[0] == '/')
 		filename++;
 	outbuf = xmalloc(strlen(path)+strlen(filename)+1+(lc==NULL));
-	sprintf(outbuf, (lc==NULL ? "%s/%s" : "%s%s"), path, filename);
+	sprintf(outbuf, "%s%s%s", path, (lc==NULL)? "/" : "", filename);
+
 	return outbuf;
 }
diff --git a/libbb/last_char_is.c b/libbb/last_char_is.c
index a95e57c35..4e2ee92ed 100644
--- a/libbb/last_char_is.c
+++ b/libbb/last_char_is.c
@@ -28,7 +28,10 @@
  */
 char * last_char_is(const char *s, int c)
 {
-	char *sret  = (char *)s+strlen(s)-1;
+	char *sret;
+	if (!s)
+	    return NULL;
+	sret  = (char *)s+strlen(s)-1;
 	if (sret>=s && *sret == c) { 
 		return sret;
 	} else {