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Kill process in bash that runs more than specified time?

Answer 1

+6 A:

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

Charles Duffy 2009-10-04 14:03:21

AFAIR we could use WAITPID in bash? And what about waitpid + WHOHANG option in while-loop that measure time that past since exec and terminates then? (I think instead of "if [[ ! -e /proc/$child_pid ]] ; then" construction?)

zmische 2009-10-04 14:22:05

You recall incorrectly; bash's wait construct accepts a pid as an argument, but nothing else (no timeout, so you lose much of the power of the actual waitpid syscall).

Charles Duffy 2009-10-04 14:23:36

...but yes, if we could do that, it would be *much* less evil. :)

Charles Duffy 2009-10-04 14:26:32

Updated to remove the /proc/$child_pid reference.

Charles Duffy 2009-10-04 14:31:33

I looked through my past projects and found, that I'd used waitpid in PERL when forking childs for multithreading of the script. So you were right - no waitpid with params in bash!

zmische 2009-10-04 16:13:57

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Kill process in bash that runs more than specified time?

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