Catching SIGINT to cleanup from a MongoDB mapReduce command

FooCommand.php

<?php

namespace OpenSky\Bundle\MainBundle\Command;

use Symfony\Bundle\FrameworkBundle\Command\Command;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Input\InputOption;
use Symfony\Component\Console\Output\OutputInterface;

class FooCommand extends Command
{
    protected function configure()
    {
        $this
            ->setName('foo')
            ->addOption('timeout', 't', InputOption::VALUE_REQUIRED, 'MongoCursor timeout', 0)
        ;
    }

    protected function execute(InputInterface $input, OutputInterface $output)
    {
        $tmp = uniqid('foo.');
        $output->writeln(sprintf('Using <info>%s</info> as the temporary collection.', $tmp));

        \MongoCursor::$timeout = $input->getOption('timeout');
        $dm = $this->container->get('doctrine.odm.mongodb.document_manager');
        $db = $dm->getDocumentDatabase('OpenSky\Bundle\MainBundle\Document\Foo');

        $cleanup = function() use ($db, $tmp, $output) {
            $db->$tmp->drop();
            $output->writeln(sprintf('Dropped temporary collection <info>%s</info>.', $tmp));
            exit;
        };

        declare(ticks = 1) {
            pcntl_signal(\SIGINT, $cleanup);

            $db->command(array(
                'mapreduce' => 'seller_followers',
                'map' => new \MongoCode('...'),
                'reduce' => new \MongoCode('...'),
                'out' => $tmp,
            ));
        }

        call_user_func($cleanup);
    }
}