Extensible CceWrap With Capabilities
====================================

This document describes the changes to be to ccewrap in order to gmake it's
configuration more extensible.  

As it currently stands, ccewrap has a very simple configuration called
/etc/ccewrap.conf .  The format of this file is simple: simply state the name of
the program you wish to let ccewrap work with.  Ccewrap currently checks two
things: the credentials of the user against cce and the existance of the
executable in the config file.  It then proceeds to setuid itself to the calling
user's uid.

The proposed change is to use a drop config directory named /etc/ccewrap.d/ that
would allow modules to simple drop in .xml files to register themselves with
ccewrap.  This is the approach that was taken with cce and has proven quite
effective. 

The syntax of entries for the XML ccewrap config file is as follows:

	- A "program" element that has the following attributes
		- "name" - the name of the program to configure
	- A "capability" element.  All "capability" elements must have "program"
	  elements as their parents.  This element has the following attributes:
	  	- "requires" - A name of a capability that cce can understand,
		  or "" to allow any user to run this program.
		- "user" - Optional - Default = "" - The username that
		  this program would be run as if the capability name is
		  matched.

All "program" elements will have a default "Capability" element with require=""
and user="".

When a client application invokes ccewrap, they will be required to supply a new
environment variable named CCE_REQUESTUSER.  This variable represents the
username of the user that the calling application wishes to run the wrapper as.
This environment variable will always default to requesting the calling user
when left blank. 

In keeping with our idea that admin==god, if a user authenticates and their
.systemAdministrator flag is set, then to run an application, it need only be
present in the configuration files.  No checks to see whether this user matches
the required capabilities will be done.  To explictly have a program run as
the actual user rather than as root, the CCE_REQUESTUSER environment variable
must be explicitly set to something other than blank or NULL.

To maintain backwards compatibility, the old configuration file
/etc/ccewrap.conf will still be read and used for configuration with the
previously mentioned defaults although it's use may eventually become
deprecated.