Kill process in bash that runs more than specified time?

Question

I have a shutdown script for Oracle in /etc/init.d dir on "stop" command it does:

su oracle -c "lsnrctl stop >/dev/null"
su oracle -c "sqlplus sys/passwd as sysdba @/usr/local/PLATEX/scripts/orastop.sql >/dev/null"

.. The problem is when lsnrctl or sqlplus are unresponsive - in this case this "stop" script just never ends and server cant shutdown. The only way - is to "kill - 9 " that.

I'd like to rewrite script so that after 5min (for example) if command is not finished - it should be terminated.

How I can achieve this? Could you give me an example? I'm under Linux RHEL 5.1 + bash.

Answer 1

If able to use 3rd-party tools, I'd leverage one of the 3rd-party, pre-written helpers you can call from your script (doalarm and timeout are both mentioned by the BashFAQ entry on the subject).

If writing such a thing myself without using such tools, I'd probably do something like the following:

function try_proper_shutdown() {
  su oracle -c "lsnrctl stop >/dev/null"
  su oracle -c "sqlplus sys/passwd as sysdba @/usr/local/PLATEX/scripts/orastop.sql >/dev/null"
}

function resort_to_harsh_shutdown() {
  for progname in ora_this ora_that ; do
    killall -9 $progname
  done
  # also need to do a bunch of cleanup with ipcs/ipcrm here
}

# here's where we start the proper shutdown approach in the background
try_proper_shutdown &
child_pid=$!

# rather than keeping a counter, we check against the actual clock each cycle
# this prevents the script from running too long if it gets delayed somewhere
# other than sleep (or if the sleep commands don't actually sleep only the
# requested time -- they don't guarantee that they will).
end_time=$(( $(date '+%s') + (60 * 5) ))
while (( $(date '+%s') < end_time )); do
  if kill -0 $child_pid 2>/dev/null; then
    exit 0
  fi
  sleep 1
done

# okay, we timed out; stop the background process that's trying to shut down nicely
# (note that alone, this won't necessarily kill its children, just the subshell we
# forked off) and then make things happen.    
kill $child_pid
resort_to_harsh_shutdown