sub spawn
{
    my ($timeout, @cmd) = @_;

    defined( my $child_pid = open(CHILD_OUTPUT, "-|" )
        or die "fork: $!";

    if ($child_pid)
    {
        # parent
        eval
        {
            local $SIG{ALRM} = sub { timeout($child_pid); };
            alarm $timeout;
            while (<CHILD_OUTPUT>)
            {
                # log it
            }
            close(CHILD_OUTPUT) or warn "process $child_pid exited: $?";
            alarm 0;
        };

        if ($@)
        {
            print "oops: $@";
        }
    }
    else
    {
        # child
        exec @cmd or die "exec: $!";
    }
}