I got the idea of implementing a user access-control
daemon. I coded a simple program called utmpd which
role is to force logout users violating a defined rule.

Eg.: We set the configuration file to kill user "test",
every time he logs in to the system from Monday to Friday.
Every time the user "test" tries to log in at these days
(Mon,Thu,...Fri) he receives a message on his terminal:

"You are not allowed to log in on this day!"

and gets killed.

Other options that utmpd supports are :

DENY_TIME (denied access at predefined time,
time ranges...)

WDENY_TIME (explained above)

HOST_DENY (killing users loged from certain
hosts (eg. microsoft.com !sorceforge.net ))

MAX_IDLE (sets the maximum idle a user can reach)

I hope someone will find my program useful and try to use it, else my work was partially wasted.

http://utmpdix.sourceforge.net/

I don't want to dismiss your programming efforts, but can you comment on what your daemon does that isn't possible by other means or how is differs from existing solutions? Cause the examples you gave are already available through eg pam_time, hosts.[allow|deny], autolog, idled, ...