I am running Ubuntu GNOME 14.04, using gdm display manager and gnome-shell environment and I need to achieve the following behaviour: after boot, a selected user is automatically logged in, but a password is still needed to access the session. Or in other words, after the user is automatically logged in, the screen is locked immediately.
The user login is specifically needed; it's not about starting a service at boot time (which is achievable with different means).
Is this behaviour possible? If so, how to do it in the most clean and non-hacky way? Changing the display manager or the environment is not an option.
Thanks for any input.
