klprPDE - CUPS to LPRng + Kerberos Authentication
Copyright 2004, NC State University
Refer to the installer license dialog for license information.

           Modified by Patrick Powell
          Mon Jan 31 15:58:30 PST 2005

Introduction

The klprPDE package is a Printer Dialog Extension(PDE) and cups
backend which implements printing to a kerberized LPRng print server.
The PDE runs in user space at print time and loads whenever the
standard Apple print dialog is called to get and cache a kerberos
ticket for the print server(s). The cups klpr backend is a version
of the LPRng lpr client which takes cups arguments and reads the
cached kerberos service tickets.

This free software is released free under a BSD type license.

This note is a modified version of the original note
on the http://www.ncsu.edu/mac/software/klprpde.html site.

klprPDE Authors: 
Hua Ying Ling - Code, design, and implementation.
Everette Gray Allen - Concept, direction, testing and documentation.
Email: help@ncsu.edu

Warranty:
                NO WARRANTY

  BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
REPAIR OR CORRECTION.

  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR
REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES,
INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING
OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED
TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY
YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.

Credits:

The authors wrote the printer dialog extension in this package.
The cups backend was modifed from work done by the following folks:
Patrick Powell wrote LPRng.  See http://www.lprng.org/. Our cups
backend is a version of the lpr command line tool from LPRng version
3.8.12 modified to accept cups style options and a path to the
ticket cache file.  Sam Hartman wrote the modifications of LPRng
version 3.8.12 to make it work with the MacOS X kerberos model. The
source distribution contains his modifications with his permission.

In addition, Rick Cochran at Cornell CIT has provided testing,
review and debugging for this code.

Requirements:

MacOS X 10.3.  klprPDE will not work on earlier versions of MacOS
X due to a known bug in kerberos credential caching.
There is no version for MacOS 9 or 10.0/1 since cups is not available
in those OS versions.  There never will be a port to any other
operating system.  It is possible to use the klprPDE derivative of
our work from Reed University on other versions of MacOS X.  See:
http://www.reed.edu/~nobles/reed/osx_klpr.html

Note that this version may work with later versions of MaxOS X,
as long as the CUPS PDE interface does not change and the Kerberos
library support is present.

(From the original notice:)
#  Download
#      Binary Installer - http://www.ncsu.edu/mac/downloads/klprPDE.zip
#      Source - http://www.ncsu.edu/mac/downloads/klprPDE.src.zip
#      License - http://www.ncsu.edu/mac/software/license.html

Installation:
  a) configure LPRng with: 
       configure --enable-kerberos --enable-klprpde
     OPTIONAL:
      --with-klpr_auth=kerberos   - use original kerberos authentication
      --with-klpr_auth=k5conn     - use k5conn authentication
     OPTIONAL:
       --disable-require_configfiles - client programs require lpd.conf, printcap
  b) compile and install using:
       make install
  c) copy or make a symbolic link to lpr:
      ln -s /usr/local/bin/lpr /usr/libexec/cups/backend/klpr
    OR
      cp /usr/local/bin/lpr /usr/libexec/cups/backend/klpr
  d)  Install klprPDE.plugin in /Library/Printers/PPD Plugins/klprPDE.plugin
    (copy the directory and files:
      cp -r klprPDE.plugin '/Library/Printers/PPD Plugins/klprPDE.plugin'
    OR
      mv klprPDE.plugin '/Library/Printers/PPD Plugins/klprPDE.plugin'

Configuration:

The configuration files are at:
  /Library/Printers/PPD Plugins/klprPDE.plugin/Contents/Resources/Settings.strings

There is no GUI interface to edit this files.  Edit the file with
a text editor like TextEdit, BBEdit, pico, vi, emacs, etc.  Text
enclosed in /* */ is ignored (C style comments) for Settings.strings
only.  Settings.strings is within the klprPDE bundle and should
look like this:

FILE:
  /Library/Printers/PPD Plugins/klprPDE.plugin/Contents/Resources/Settings.strings

CONTENTS:

/*====== These strings are CASE SENSITIVE ========*/

/* these strings are matched in this order
- print server  (the hostname of the print server)
- printer type
- service name
    at least one of these must match the printer or job settings
    or the PDE will not load
*/

/*
  if the hostname of the print server matches the first string
  then the use the second string as the service name*/
  Example:
  "net-print.cit.cornell.edu" = "lpr/net-print.cit.cornell.edu@CIT.CORNELL.EDU";
  "page3.cit.cornell.edu" = "lpr/page3.cit.cornell.edu@CIT.CORNELL.EDU";
  "irene.cit.cornell.edu" = "lpr/irene.cit.cornell.edu@CIT.CORNELL.EDU";
*/


/*
  if the printer type matches the first string
  then use the second string as the service name
  By default, the printer type is 'klpr'
  Example:
   "klpr" = "lpr/printservername.whatever.dom@REALM.WHATEVER.DOM";
*/

/*
  Match 'Service Name' - the default name for the service
  Example:
    "Service Name" = "lpr/printservername.whatever.dom@REALM.WHATEVER.DOM";
*/

=====

The lpd.conf file does not have to be present.

Server Configuration:

The server should accept connections without any problems.  If you want to
enforce Kerberos authentication:

ACCEPT SERVICE=R AUTH=kerberos,k5conn
REJECT SERVICE=R


Known Issues

1) There is no preference interface.  Preference changes must be
made by editing /Library/Printers/PPD
Plugins/klprPDE.plugin/Contents/Resources/Settings.strings
with a text editor like BBEdit, pico, vi,
emacs, etc.

2) Applications with custom print dialogs like some major Adobe
apps. will never load Apple's default print dialog which means the
PDE code will never execute.  The work-around is to use the Printer
button in the custom dialogs to get the standard Apple print dialog
so the PDE to run.