The two Perl modules "Encode" and "MIME::Parser" are required by controlchan.
To reduce load, controlchan keeps a copy of control.ctl and control.ctl.local in memory and checks permissions (including any required PGP headers) before any scripts are called. These two configuration files are automatically reloaded when controlchan notices they have been modified. Also, the default case of an unrecognized control article is handled internally. The "drop" case is handled with far less fuss.
Normally, controlchan is invoked by innd as configured in newsfeeds. An example entry is below. Make sure that the newsgroup "control.cancel" exists so that controlchan does not have to scan through cancels, which it will not be processing anyway.
controlchan!\ :!*,control,control.*,!control.cancel\ :AC,Tc,Wnsm\ :<pathbin in inn.conf>/controlchan
controlchan can also be manually invoked with a mere path to a file (containing a complete control article with its headers and its body) or a token on its standard input:
echo '/path/to/a/control/article' | controlchan echo '@0303465234000000000000235AE000000002@' | controlchan
Note that in the (very, very unlikely) event that you need to process ihave/sendme control messages, be sure that logipaddr is set to false in inn.conf, because in this case controlchan needs a site name, not an IP address.
controlchan tries to report all log messages through syslog(3), unless connected to an interactive terminal. To enable syslog(3)'ing for versions of Perl prior to 5.6.0, you will need to have run h2ph on your system include files at some point (this is required to make "Sys::Syslog" work). If you have not done so, do this:
cd /usr/include h2ph * sys/*
If you run FreeBSD, you will need to run the following in addition: