How do login managers work?

ButterflyMelissa · 12-20-2020, 01:44 PM

Hi all,
The title basically says it all.
I'd like to delve into ncurses using C as an effort to further my programming skills.
I do have a Bachelor degree, but I have nog been given any C...strange. I feel like a car mechanic that has no clue how to change tires...
So. Just to set a goal...
Thanks a bunch
Lov ya
Melissa

SoftSprocket · 12-20-2020, 02:40 PM

init manages logins. It calls getty (or I guess agetty) and then invokes login to check credentials.

ncurses is independent of the terminal so writing ncurses programs don't require you manage the terminal.

michaelk · 12-20-2020, 09:46 PM

agetty is the program that manages login to the console or virtual terminal. Graphical display managers i.e. xdm, ldm, gdm etc display the login prompt from the desktop.

xdm was the original display manager and might provide a starting point.

https://en.wikipedia.org/wiki/X_display_manager
https://www.linuxjournal.com/article/4720

ncurses is a library that provides an API to create text based visual i.e GUI like interface for the console. Midnight commander which is a file manager is an example of an ncurses application.

While the tldp is dated it does provide somewhat of a beginning guide.
https://tldp.org/HOWTO/NCURSES-Programming-HOWTO/