Autologin when pam allows

[necauqua]

I am not sure how correct my request is, but for example standard lightdm greeter allows you to login without entering your password when some pam module gives you sufficient rights to do so.

So when you have some pam module with 'sufficient' qualifier (or how it is called) and that module gives you permissions without interaction somehow, you can have such button or just automatically log in.

In my case it's pam_usb - on Ubuntu when i plug my USB key (with pamusb.conf configured for my user ofc) in it shows just Log in > button in place of password field.

[prikhi]

So basically, start with a password box & if pam gives autologin access then switch to a "Log In" button, or just automatically log in? I'd be down to support this but I can't give an estimate on when I'd be able to get to it & it'll probably require a bit of code restructuring.

I know the lightdm library provides some lightdm_greeter_*_autologin_* functions but I don't know if they integrate with pam, will have to checkout how the default gtk-greeter does it.

[necauqua]

You can test it with pamusb and any flash drive (i might have mislead you in calling my old flashstick a 'key').
You can have a config options for choosing between button and just autologin?
Although idk what to do when using a screenlocker, always the button maybe?