unix_update - Helper binary that updates the password of a given user
unix_update is a helper program for the pam_unix module that updates
the password of a given user. It is not intended to be run directly
from the command line and logs a security violation if done so.
The purpose of the helper is to enable tighter confinement of login and
password changing services. The helper is thus called only when SELinux
is enabled and in the enforcing mode on the system.
The interface of the helper - command line options, and input/output
data format are internal to the pam_unix module and it should not be
called directly from applications.
Written by Tomas Mraz and other various people.