Hello, I'm having a bit of a problem with using $SIG{ALRM} to kill a child process.

I wrote this script to take two arguments, alarm time and command to execute. The script is called runtimed: 
my $status = 0;
my $maxTime = shift @ARGV;
my $runCmd = join ' ', @ARGV;

$SIG{ALRM} = sub { die "timeout" };

eval {
        alarm($maxTime);
        `$runCmd`;
        alarm(0);
};

if ($@) {
        if ($@ =~ /timeout/) {
                local $SIG{'HUP'} = 'IGNORE';
                kill('HUP', -$$);
                $status = 1;
        }
}

exit $status;

[download]
I want be able to call runtimed from different scripts, with different times and commands to execute.

Here's the test script I call it with: 
my $FIND = '/usr/bin/find';
&finder($FIND, ' . -name somename -print');

sub finder {
        my ($cmdName,$cmdOptions) = @_;
        my $cmdExecute = $cmdName . $cmdOptions;
        chdir "/";
        my $res = `/usr/bin/perl runtimed 3 $cmdExecute`;
        print "$res\n";
        return 0;
}

[download]
I use the test script to call runtimed with a three-second alarm and a find command to execute.

The result I get is that the test script dies after three seconds, but the find command continues to run. If I hard-code the alarm time and the find command into runtimed and just execute that, it kills the find command.

I'm using Perl version 5.8.0 on Red Hat Linux 3.2.2-5. I've read about Perl "safe" signals and how those sometimes aren't able to break in and kill a child process. I don't think this is my problem, though, since I'm able to kill the find command if I hard-code it into runtimed.

Thanks for any help,

Ryan

In reply to SIG{ALRM} Question by rrucker

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