Old houses with hard-to-snake rooms have relied on pull chain lamps to get central lighting. Ten years ago there were a variety of pull chain lamps marketed online and through big box stores as such. That has changed slowly, such that now there are only really three options.
First, there's a cheap ($10) version that typically comes with a square diffuser glass. This mounts to the ceiling about as well as a soda can with a nail through it. Don't buy it unless it's an emergency. It'll be a wobbly reminder of a job half done, and the switch is going to break in 18 months.
The one advantage the $10 version has is that its switch is vertically oriented. This is very important to reduce side-loads on the fixture and switch.
The second option is a round lamp with a bucket-shaped diffuser that has its switch on the side. This version is also wobbly, and the weirdly oriented switch means a tenant is going to be pulling hard to the side to get it to work. Say goodbye to that chain, the switch and maybe to your diffuser glass, too.
Replacement switches can be purchased in most box stores, but the wiring inside the cheap lamps is far too short to safely cut and replace the switch. Don't bother.
Option three is to purchase a ceiling fan light kit. These are much sturdier and have the all-important feature of a central, vertically oriented switch. Not all light kits are marketed to be ceiling mountable. Check that the model is ceiling mountable (flush mountable) before purchasing.
Light kits may come with a variety of finishes inside the box. For $20, with an average life of many years, this makes them a far better value than the $10 fixture that could die after 18 months.
Whatever you do, the best advice is now to hire a licensed electrician to snake in a wall switch and forget about pull chain lamps forever. Wall switches probably don't fail even after 30 years, and they expand your choices for light fixtures enormously. They will be far less headache for you over the long term, and cheaper, too, even with the cost of the electrical figured in.