Need to auto-login after logout on ubuntu

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http://unix.stackexchange.com – I've set up a kiosk using Ubuntu 12.04, and I'd like to have it autologin after a user logs out or if the screen locks, in case someone manages to get back to lightdm or tries to login to the non-kiosk account after a reboot. I've tried setting display-setup-script in lightdm.conf to run xautolock to trigger restarting lightdm, but that just causes Ubuntu startup in low graphics mode. So basically, if lightdm is active instead of a user being logged in, log in the kiosk user. (HowTos)