On Tue, 2 May 2006, Hans-Werner Hilse wrote:
Based on the suggestions of Uwe and Vladimir, I tried trap 'pkill -TERM -P $$; kill -s TERM $$' TERM <do something> . /path/to/child.sh <do something else> Doesn't work, yet. Note that child.sh is a shell script that may execute some other command (like rsync), so the "." by itself may not be enough.This can't work because of this (man bash): --snip If bash is waiting for a command to complete and receives a signal for which a trap has been set, the trap will not be executed until the command completes. --snip
Oops...!
What instead works (just tested): --snip #!/bin/sh COMMAND="sleep 120" # First we background: $COMMAND & # Save the PID CHILDPID=$! # Trap the signal: trap "kill -TERM $CHILDPID" TERM # And wait for the Child to finish: wait $CHILDPID # reset signal handling: trap - TERM --snip
Backgrounding is really not an option. The whole setup is to be supervised by daemontools.
Note that the code could hit a racing condition and should therefore not carelessly run by root on a machine with untrusted users. This is: The process may have finished before setting the signal handler. Other processes *might* reuse the PID afterwards and might get sig-TERM-ed until resetting the signal handler again. Probably a minor, depending on the script's usage.
Precisely the kind of thing I want to avoid. I think I need to reformulate my setup.
Thanks. Jorge Almeida -- [email protected] mailing list
