Date: Sun, 6 Mar 2005 17:09:21 +1030 From: Malcolm Kay <malcolm.kay@internode.on.net> To: <freebsd-questions@freebsd.org> Subject: Timeout in bourne scripts. Message-ID: <200503061709.21158.malcolm.kay@internode.on.net>
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I am running some bourne scripts which occassionally
lock up with a LAN failure during an 'rdist' transfer
or other 'ssh' based communication. I need some method
of making these operations timeout in the case of
problems without losing the exit when time out
doesn't happen.
I have attempted (successfully I think) to roll my own
but I feel sure I must be missing a previous invention
of the wheel.
For what it is worth here is a test of the code I am
proposing:
----to.sh---------------------------------------------------
#!/bin/sh
timeout()
{
debug()
{
#comment the next line to disable debug messages
#echo "$*"
}
base=/tmp/`basename $0`.$$
# use tmax for maximum time (i.e time in seconds to time out)
# use tres for time resolution (seconds) in testing for completion
report()
{
$@ &
echo $! > $base.pid
wait $!
echo $? > $base.stat
}
report "$@" &
sleep $tres
tmax=$(($tmax-$tres))
pid=`cat $base.pid`
debug pid=$pid
while [ $tmax -gt 0 ]
do
ps -p $pid >/dev/null || break
debug "seconds to time out=$tmax"
sleep $tres
tmax=$(($tmax-$tres))
done
[ $tmax -gt 0 ] || kill -KILL $pid > /dev/null 2> /dev/null
stat=`cat $base.stat`
rm -f $base.pid $base.stat
return $stat
}
#test using command line arguments
tmax=$1 tres=$2 timeout "$3"
echo status=$?
#check to see that no unexpected
# processes are still running
ps x
-------------------------------------------------------------------------
To test this I use soemthing like:
% ./to.sh 7 1 "sleep 5"
or
% ./to.sh 5 1 "sleep 7"
Any comments appreciated
Malcolm
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