Add a selfpipe to runsvdir to synchronize signal handling with i/o, just as the runit and runsv programs do. This makes SIGCHLD handling faster. Improve the readproctitle log and standard error processing with a buffer.

Did you consider the possibility of using signalfds?

If the runsvdir program is built on a system that supports inotify(7), it now uses the inotify API to watch the services directory dir.

This is great to see, thank you!

I did actually do some work on a similar patch myself, but I couldn't get everything right. Perhaps I will take a look at the two versions when I get time in case there's anything I spotted.

Add a selfpipe to runsvdir to synchronize signal handling with i/o, just as the runit and runsv programs do. This makes SIGCHLD handling faster. Improve the readproctitle log and standard error processing with a buffer.

Did you consider the possibility of using signalfds?

No, for me the selfpipe trick works just fine and is well tested.

If the runsvdir program is built on a system that supports inotify(7), it now uses the inotify API to watch the services directory dir.

I did actually do some work on a similar patch myself, but I couldn't get everything right. Perhaps I will take a look at the two versions when I get time in case there's anything I spotted.

Review, testing, bug fixing welcome!

With inotify(7), the current implementation doesn't work correctly if dir is the first of a chain of symlinks to the services directory. In this case runsvdir only gets events on changes in the first and last element of the chain, not the intermediates.