Coda File System

Re: coda looses group ownership

From: Enrico Weigelt <>
Date: Tue, 27 Feb 2007 14:49:05 +0100
* Davor Ocelic <> wrote:


> I find Unix permissions too restricted and getting messed up 
> all the time when you try to do user magic with them.
> For system stuff, Unix permissions are ok, but for higher-level 
> thinking and user convenience, ACLs in AFS or Coda style are great.

It always depends on what you're doing with the machines. 

When I came to GNU/Linux about 12 years ago, I used to use
Novell 4.x, which supported ACLs. Well, it required some
rethinking and from a plain-user view it wasn't comfortable. 
But over the years I learned to like it, since its simple
and effient - good for environments where confortability is 
not required (ie. webservers, really few useres per system,...)

The big problem is how to bring these two different concepts
together. Maybe it's good first to think about how we could 
(partially) simulate ACLs in the classical unix permission
system: each distinct ACL (in Novell words: trustee set) is 
represented by an group. 

And now some diferrent view: what does an unix permission
mean in ACL words ? Well, each file has an ACL with the
    * 1. ownership: the one who's allowed to change the ACL
    * 2. permissions for the one who owns the file
    * 3. permissions for some group 
    * 4. permissions for the 'world'-group (all users)
As long as we've got this structure (the admin will have to 
take care of that), we can easily map ACLs to unix permissions 
and vice versa. Venus can maintain an table of mappings between 
local and coda groups. 

So, for example if I run chgrp on some file, it actually
replaces the group in the 3rd trustee.

 Enrico Weigelt    ==   metux IT service

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Received on 2007-02-27 08:52:01