Using io_uring to make a high-performance... finger server May 24, 2021 on Drew DeVault's blog
I’m working on adding a wrapper for the Linux io_uring interface to my secret programming language project. To help learn more about io_uring and to test out the interface I was designing, I needed a small project whose design was well-suited for the value-add of io_uring. The Finger protocol is perfect for this! After being designed in the 70’s and then completely forgotten about for 50 years, it’s the perfect small and simple network protocol to test drive this new interface with.
In short, finger will reach out to a remote server and ask for information about a user. It was used back in the day to find contact details like the user’s phone number, office address, email address, sometimes their favorite piece of ASCII art, and, later, a summary of the things they were working on at the moment. The somewhat provocative name allegedly comes from an older usage of the word to mean “a snitch” or a member of the FBI. The last useful RFC related to Finger is RFC 1288, circa 1999, which will be our reference for this server. If you want to give it a test drive, try this to ping the server we’ll be discussing today:
You might also have the finger command installed locally (try running “finger drew@drewdevault.com”), and you can try out the Castor browser by sourcehut user ~julienxx for a graphical experience.
