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francma / wob

A lightweight overlay volume/backlight/progress/anything bar for Wayland.
ISC License
896 stars 49 forks source link

main: Handle poll close events. #53

Closed KalilDev closed 4 years ago

KalilDev commented 4 years ago

Previously, wob would ignore POLLHUP and get stuck on the for(;;) loop in main, using 100% cpu. Do you want me to add tests or an minimal repro?

francma commented 4 years ago

That's a good catch. I think it can be reproduced by deleting the named pipe.

I think it would be better to remove the if check before reading and let the fgets == NULL check do that for us (maybe only handle POLLERR). If I'm reading man page for poll correctly, there can be both POLLIN and POLLHUP flags set at the same time so it's should be more correct to move the POLLHUP check at the end of the default switch case.

KalilDev commented 4 years ago

Okayy, did it as you sugested. Sorry for the sloppy code, im not too familiar with C. The test case is an simple program that outputs some values and then exits. When piping it to wob it got stuck on the for loop as expected, and after the commit, wob exits gracefully. I subscribed to POLLERR events and handled them so the user is notified of the problem. The case where both POLLIN and POLLHUP should be handled now, but i couldn't recreate this case, if you have any suggestions.

francma commented 4 years ago

Decided to write my own fix for this b144c3cceb09b22483b0f66ea420d677d3dc425d

Unexpectedly closed fd can be simulated via sleep 1 | wob.