Chapter 4. Generic optional arguments
Here we list the generic arguments that all modules can expect to be passed. They are not mandatory, and their absence should be accepted without comment by the module.
Use the pam_syslog(3) call to log debugging information to the system log files.
The module should not prompt the user for a password. Instead, it should obtain the previously typed password (by a call to
PAM_AUTHTOKitem), and use that. If that doesn't work, then the user will not be authenticated. (This option is intended for auth and passwd modules only).