On May 17, 12:35 pm, kelly.terry.jo...@gmail.com (Kelly Jones) wrote:
> These 3 lines of code:
>
> if (fork()) {sleep 10; exit(0);}
> $SIG{'CHLD'} = 'IGNORE';
> exit(system("/usr/lib/nagios/plugins/check_ping -H google.com -w
> 500,20% -c 1000,40% 1> /tmp/stdout.txt 2> /tmp/stderr.txt; echo $? >
> /tmp/res.txt"));
>
> return "PING WARNING - Packet loss = 0%, RTA = 62.08
> ms|rta=62.077999ms;500.000000;1000.000000;0.000000 pl=0%;20;40;0" into
> /tmp/stdout.txt and 256 into /tmp/res.txt (/tmp/stderr.txt remains
> empty).
>
> If I comment out the 2nd line, it returns "PING OK - Packet loss = 0%,
> RTA = 62.86 ms|rta=62.862999ms;500.000000;1000.000000;0.000000
> pl=0%;20;40;0" in /tmp/stdout.txt and 256 into /tmp/res.txt (weird?),
> with /tmp/stderr.txt remaining empty.
>
> Why does SIG{CHLD} affect whether I get "PING WARNING" or "PING OK"?
>
> I ran this test several times, so this isn't google.com being slow/fast issue.
>
> I also realize that the first result ("PING WARNING") is odd, since
> the RTA and packet loss look fine.
>
\
I'm not sure why your code is written this way. Why does
the parent just sleep and exit? Are you perhaps trying to
avoid a stalled fork parent if check_ping bogs down...?
(check 'perldoc -q timeout' for better options.)
Since, check_ping fails in both cases ("256 in /tmp/res.txt),
did you the check_ping docs for conditions that generate
errors..? Does that particular check_ping call run ok from
the command line?
If you're trying to avoid a zombie and don't want to simply
comment out the signal ignore, why not just do a wait,
since the 'system' call will block until check_ping finishes
anyway:
my $pid = fork();
die "fork error: $!" unless defined $pid;
if ($pid) # parent
{
my $child = waitpid( $pid, 0 );
print "reaped: $child check_ping exit status: $?\n";
}
elsif (defined $pid) # child
{
exec("/usr/lib/nagios/plugins/check_ping -H ... ")
or warn " can't exec: $!";
}
--
Charles DeRykus
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