pj VS shadow

I wrote a 'subreaper' program to capture and kill such things some time ago. It's pretty basic, having options to pass on signals, start killing subprocesses if it receives a signal, or killing subprocesses after the initial subprocess dies. There is an undocumented --all that prints logs, kills on stats and doesn't start killing when the main program dies. I use it for killing test subprocesses or capturing things to terminals that would otherwise double-fork out of them, allowing me to kill them and all their subprocesses with a ctrl-c.

https://github.com/knome/pj

>Linux is in the middle of adding new APIs like pidfd_send_signal, but none of them are aimed at improving the situation with grandchildren.

While my subreaper is vulnerable to pid reuse, but I think it could be fixed by having it do this:

    loop

Cool, will be interested to see how this develops! tokio's loom framework has been a big help in testing some tricky concurrency code I've worked on.

Folks interested in this space might also be interested in the system I spend most of my time working on: Shadow. It also performs deterministic simulation of a network of hosts, but it intercepts network and system interactions at the syscall level via seccomp. As such it can work with binaries compiled from ~any language, usually without any code modification or special compilation. https://shadow.github.io/

Nice writeup! I've also had to dig a bit into this area in my work on shadow.

It is no longer active. If you are asking about Shadow, check out https://shadow.github.io

I do share this hesitation. I think for simple cases iterators are usually fine, but I've definitely run into cases where an iterator adapter caused unexpected performance problems. e.g. https://github.com/shadow/shadow/pull/2543

Yes. Though I'm not sure I see the connection to the OP...?

The example I'm most familiar with, because I work on it, is Shadow. We used ptrace for a bit but now use seccomp.

https://github.com/shadow/shadow/

For anyone interested in following current development on Shadow, we've been publishing a series of updates. Most recent: https://github.com/shadow/shadow/discussions/1274

The previous update has links back to the whole series; I stopped including it in the most-recent update since it was getting a bit cumbersome: https://github.com/shadow/shadow/discussions/1060