Subprocess after fork

[wolfv]

Hi, thanks for the awesome crate – it's very useful.
I am trying to daemonize a process, but after daemonizing it I still need to start a Command (sub-process). Somehow the child just seems to abort.

Do you happen to know if this is a known issue? Do I need to set some permissions correctly? This is on macOS and I haven't tried Linux yet.

Cheers!

[wolfv]

I actually think that it's some interaction with tokio and not with the subprocess. Maybe we need to start a new tokio runtime in the child.

[xadaemon]

I actually think that it's some interaction with tokio and not with the subprocess. Maybe we need to start a new tokio runtime in the child.

Likely yes, remember that the child is a completely new process and tokio might not play well with that.

[xadaemon]

Try creating a simple POC to test the hypothesis I don't have a mac on hand right now where I could do a test to confirm, I might do a quick test on linux see what happens, but my guess it's tokio being unhappy about being forked

[xadaemon]

Actually tokio-rs/tokio#4301 this would point to that

[wolfv]

Thanks @neonimp – I'll close this issue for now and do some additional testing. If we come up with some solution, maybe we can add it to the examples :)

[xadaemon]

Not sure if tokio has something for this to work, but I would try to do the forking and then use one of the hooks provided by the lib to start tokio after the fork @wolfv

[xadaemon]

Yes, do a non tokio main that sets up the code and calls the demonization code, https://docs.rs/tokio/latest/tokio/runtime/index.html#usage then with a child hook and a parent hook start tokio and do whatever you may need to do.

[xadaemon]

Did you get a chance to test that theory @wolfv I will add it to the docs after some testing of my own otherwise