Return the list of basic PAM services everyone would want.

Return a standard Unix-style PAM service for NAME. When ALLOW-EMPTY-PASSWORDS? is true, allow empty passwords. When ALLOW-ROOT? is true, allow root to run the command without authentication. When MOTD is true, it should be a file-like object used as the message-of-the-day. When LOGIN-UID? is true, require the 'pam_loginuid' module; that module sets /proc/self/loginuid, which the libc 'getlogin' function relies on. When GNUPG? is true, require the 'pam_gnupg.so' module; that module hands over the login password to 'gpg-agent'.

The "root" PAM service, which collects <pam-service> instance and turns them into a /etc/pam.d directory, including the <pam-service> listed in BASE. TRANSFORM is a procedure that takes a <pam-service> and returns a <pam-service>. It can be used to implement cross-cutting concerns that affect all the PAM services.

Convert a pam-limits-entry record to a string.

Construct a pam-limits-entry ensuring that the provided values are valid.