Launchd at logout

Question

launchd allows you to start an application, say open a text editor, just as user gets the desktop (after logging into console) using the RunAtLoad option. Now, even though https://developer.apple.com/library/mac/documentation/macosx/conceptual/bpsystem startup/chapters/CustomLogin.html says otherwise, the logout script still works in 10.9. But it does not seem to behave the same way. What I want to do is
User tells computer to log her out of the console
Application is loaded and waits on user input.
User does her thing with said application and closes it
Logout procedure is completed and we are back to the login screen.
How can I do step 2?

Answer 1

The normal approach for this kind of thing is to have an app running in the background which blocks logout. If you create an applescript like the following, save it as a stay-open application, and then run it, you'll get the basic effect:
on quit
  display dialog "No logout till I say so..."
  if button returned of the result is "ok" then
  continue quit
  end if
end quit
This will cancel logout unless you click the "ok" button. You will (of course) want something more complex, but this should get you started.