On Wed, 1 Apr 2009 04:46:10 +0000 Jacob Meuser
<jake...@sdf.lonestar.org> wrote:

> On Tue, Mar 31, 2009 at 07:13:33PM -0700, OpenBSD wrote:
> > Hello
> > 
> > Could somebody please tell me how to use a dvd-rw as user?
> > I'am trying to install Slackware using qemu, and the dvd does not
> > work properly, it works well as root. I've tried adding the user to
> > operator group, users group, and declaring it at fstab without
> > optimum results.
> 
> by default root can read and write /dev/rcd0c.  operator group can
> only read.
> 
> you need to be able to write to /dev/rcd0c to put a filesystem on
> a cd/dvd.
> 
> you can change the permissions on /dev/rcd0c or use sudo.

Using sudo is a great way to handle this situation, but this depends 
on how much you trust the user, and whether or not you can properly 
configure /etc/sudoers with visudo.

NOTE: Jake only said "change the permissions" but he did not say to
change them permanently on disk. Of course, changing permissions
permanently on disk is an option, but in many situations it is not
the best option.

If as root you fumble-finger the chown/chmod command on your devices,
stuff a user into the wrong group, or don't fully understand all the
esoteric issues involved in device permissions, you could easily be 
in a world of hurt.

If you really want to go the route of changing permissions on a
workstation, the best way to do it is using the existing features
available /etc/fbtab to change permissions on devices automatically 
and temporarily at user login and logout. See man fbtab for details.

This exact situation of an unprivileged local user needing access to
devices is the reason why fbtab exists.

-- 
J.C. Roberts

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