kres: added missing nil check for dname2str

diff --git a/daemon/lua/kres.lua b/daemon/lua/kres.lua
index 61cac2267aa5ce8d0dbe55b3a60c50cf57e80227..9d690cfef22d0cc944a99fd4a9daf08241e26f93 100644 (file)
--- a/daemon/lua/kres.lua
+++ b/daemon/lua/kres.lua
@@ -251,7 +251,11 @@ ffi.metatype( sockaddr_t, {
 
 -- Pretty print for domain name
 local function dname2str(dname)
-       return ffi.string(ffi.gc(C.knot_dname_to_str(nil, dname, 0), C.free))
+       if dname == nil then return end
+       local text_name = ffi.gc(C.knot_dname_to_str(nil, dname, 0), C.free)
+       if text_name ~= nil then
+               return ffi.string(text_name)
+       end
 end
 
 -- Convert dname pointer to wireformat string