This module is highly inspired by the PAM module written by nahil1.
This module gives the ability to authenticate if a given bluetooth device is connected to your computer.
To use this module you will need the bluetoothctl utils, you can install it on Arch Linux with this command:
sudo pacman -S bluez-utils
First modify the MAC_ADDRESS value in pam_bluetooth.c to match the MAC address of your device.
Then to install this module you should use the following commands:
make
sudo make install
Now that the module has been installed you will have to modify your PAM configuration. Just add the following line to the appropriate config file in /etc/pam.d
auth sufficient pam_bluetooth.so