Module data is data associated with a module handle that is available
for the whole module loading time so it can be used also during
different operations.
We use cgo handles to preserve the life of the go objects so any value
can be associated with a pam transaction.
In order to properly test the interaction of a module transaction from
the application point of view, we need to perform operation in the
module and ensure that the expected values are returned and handled
In order to do this, without using the PAM apis that we want to test,
use a simple trick:
- Create an application that works as server using an unix socket
- Create a module that connects to it
- Pass the socket to the module via the module service file arguments
- Add some basic protocol that allows the application to send a request
and to the module to reply to that.
- Use reflection and serialization to automatically call module methods
and return the values to the application where we do the check
