README.md

noparent

Prevents the process from finding out the PID of its parent.

notes

This is useful to protect our monitors from an owned child process doing something like:

kill(getppid(), SIGTERM);

We do this by double-forking and killing the intermediary process. This means that getppid() in the child will be 1 (the init process). We use a pipe to communicate the child's PID to the nopareent process so that we can wait for it to exit and close ourself -- ensuring that SIGCHLD is delivered up the stream.

example

$ echo PID:$$ PPID:$PPID
PID:11193 PPID:7132
$ /bin/sh -c 'echo PID:$$ PPID:$PPID'
PID:26160 PPID:11193
$ ./noparent /bin/sh -c 'echo PID:$$ PPID:$PPID'
PID:26202 PPID:1