Having a controller on 404 urls using Laravel 5

I need to have a custom controller triggered when user hits a not-existing url or when I programmatically force an App::abort(404).

How can I do it?

My 404 views need some data, and a simple blade View (or a ViewComposer) is not enough.

Thanks

PS catch-all urls is not functional, because they don't catch programmatically launched 404.

via Chebli Mohamed