Killing the children with the parent

Question

I have a program spawning and communicating with CPU heavy, unstable processes, not created by me. If my app crashes or is killed by SIGKILL, I want the subproc

Answer 1

I've seen very nasty ways of "clean-up" using things like ps xuawww | grep myApp | awk '{ print $1}' | xargs -n1 kill -9

The client process, if popened, can catch SIG_PIPE and die. There are many ways to go about this, but it really depends on a lot of factors. If you throw some ping code (ping to parent) in the child, you can ensure that a SIG_PIPE is issued on death. If it catches it, which it should, it'll terminate. You'd need bidirectional communication for this to work correctly... or to always block against the client as the originator of communication. If you don't want to modify the child, ignore this.

Assuming that you don't expect the actual Python interpreter to segfault, you could add each PID to a sequence, and then kill on exit. This should be safe for exiting and even uncaught exceptions. Python has facilities to perform exit code... for clean-up.

Here's some safer nasty: Append each child PID to a file, including your master process (separate file). Use file locking. Build a watchdog daemon that looks at the flock() state of your master pid. If it's not locked, kill every PID in your child PID list. Run the same code on startup.

More nasty: Write the PIDs to files, as above, then invoke your app in a sub-shell: (./myMaster; ./killMyChildren)