Wiring a pull chain pendant light fixture
The switch is supposed to be in the hot wire, and in your lamp the black goes to and from the switch. In the house wiring the hot wire is the one with the black insulation, the neutral has white insulation and the ground is often bare, but may be green insulation.

In your lamp base the black goes through the switch and was at one time connected to four smaller  black wires, but the connection has been broken. If you want to connect a flat polarized grounded cord to this lamp, know that the center wire in the cord is the ground (connect to the bare wire in the fixture and, of the two outside wires, the smooth one is the hot (connect to black of light fixture) and the ribbed one is the neutral (connect to white of light fixture).

EDIT

If you want to do this, you would have to attach the fixture to an electrical box (e.g., a pancake box) which would be surface mounted where you want the lamp. The cord would come out a hole in the back or side of the box and the cord would have to have a "strain relief" on it. metal pancake box

But for all the trouble you'd have to go through (and some expense) to repair and adapt this fixture, it would be better to just buy a new fixture that is designed to do what you want.