grounding wire from ceiling with no place to attach to the fixture?
Preferred solution in that case is to attach the safety-ground wire to the box with a screw (if the box is metal), or wrap it around one of the fixture's mounting screws. As long as it makes a circuit to the box and the body of the fixture, it's doing it's job. (Of course if the fixture is non-conductive, it doesn't need grounding.)