Script for Killing Process of Long Running Time in Linux/Unix

[monkfan]

Dear experts,

Since some of the process spawned by particular user/pid takes too long time to run. I have this particular task I want to achieve with Perl:

1. Get PID and running time info of a particular Username
2. Check how long is the running time.
3. Kill that process if it exceed a pre-defined threshold.

I intend to do a cron job for this Perl script.

Is there any simple way to do that with Perl? My main concern is No.1 and 2. Is there any CPAN module that get that information? For killing a process, maybe I can just use Perl's 'system' command.

[Corion]

See

1. Proc::ProcessTable
2. and the kill command in Perl

[tuxz0r]

Another possible solution, since you mentioned the system() call, is to make it a one liner,

ps -lf | grep "user" |  perl -ane '($h,$m,$s) = split /:/,$F[13]; kill
+ 9, $F[3] if ($h > 1);'

You can change the criteria for killing the process, but in this case I pick any with a TIME greater than 1 hour.

Though, this will be dependent on the particulars of the 'ps' command on your flavor of unix, most notably whether it's a BSD or SySV flavor. BSD has the -u option to select only those processes for a user, but the other does not which is why I typically just use grep "username".

If your particular ps is different, you'll only have to change the indexes into @F. In the above case, the TIME is at index 13 in the format "00:00:00" and the PID of the process is index 3 and is just an integer.

[monkfan]

Thanks so much. That's just what we need.
BTW do you know how can I put that one-liner in CRONTAB?

$ crontab -e

[tuxz0r]

You can put it in crontab directly (everything after the first five fields is considered the command),

* * * * * ps -lf | grep "user" |  perl -ane '($h,$m,$s) = split /:/,$F
+[13]; kill 9, $F[3] if ($h > 1);'

or, wrap it in a shell script and call the shell script from your crontab entry instead.

#!/bin/sh
# longprockill.sh
ps -lf | grep "user" |  perl -ane '($h,$m,$s) = split /:/,$F[13]; kill
+ 9, $F[3] if ($h > 1);'

And call it crontab like so,

* * * * * longprockill.sh

[Fletch]

Just to throw this (possibly) related tidbit out: If you're interested in / worried about how much CPU time (as opposed to wall clock time) the process is using you might look at setting RLIMIT_CPU (either by your systems per-user login defaults, or your shell's ulimit command, or from Perl with BSD::Resource). Setting that sends a signal to the process when it has over stayed its welcome and run too long (on CPU doing actual work time).

[weismat]

Alternatively you may use Unix::PID.