Re: Planning Gnome Scan Inclusion

[David Zeuthen <david fubar dk>]

On Sun, 2006-09-10 at 17:52 +0200, �ienne Bersac wrote:
> Hi,
> 
> > Ideally, you just patch gnome-hardware-manager [1] to share the scanner,
> > e.g. the g-h-m UI exposes an option in the UI
> > 
> >  [ ] Share scanners on the network
> 
> The problem is : addon has to configure saned (which is systemwide) in
> order to share devices. And that need a xinetd restart or similar. 

No no no, this is not necessary. And it's really fugly. So, g-h-m should
be able to start a saned process for every scanner that would be shared
in the desktop session. This will work because you already privileges to
access the hardware.

Ideally saned wouldn't need a configuration file, ideally you'd just
pass whatever options you need to saned. This would include the

 1) what scanner to share; and
 2) what TCP port to listen to

and maybe more. No configuration file needed. Configuration files are
just bad, it's from the days when people used a shell to get work done.

So, looking at 

 http://gd.tuwien.ac.at/linuxcommand.org/man_pages/saned1.html

it seems this is not exactly the case though it's close. So if I was
you, I'd either 

 a) send mail to the SANE people asking them for a saned that does
    what you want. May be easier if you attach a patch :-)

 b) If a) doesn't work just fork saned to do the right thing and include
    that in g-h-m

> I
> don't think that doing this in session space is good. 

Doing things like this in the desktop session is the only sane (pun
intended) way; there is simply no excuse for doing things like this
system-wide, it's just broken and doesn't work for a lot of cases,
especially not if you have more than one scanner attached. There's the
security angle too, you really really really don't want saned to run as
root if you can avoid it. This is because it listens on a network port.

Plus, I would certainly object strongly to a HAL addon that does crazy
things like rewriting inetd.conf and restarting other daemons.
Especially when the fix is easy, just ask the SANE developers for a),
I'm sure (I hope at least) they can see it's the right thing to do.

> Does users share
> printers in a per session basis ?

Sure, printers should too, everything is moving to user-owned
preferences (w/ lock-down) and moving all policy / configuration to the
desktop session. It's the only way to do things right. Doing things
system-wide is just a bad thing we picked up from the UNIX way of doing
things. It's just wrong for so many things [1] :-)

(that said, I'm not sure the CUPS people agree but we all have different
views on how a well-designed system looks.)

Does this make sense? I hope it doesn't scare you off too much, I just
think it's the right thing to do. What do you think?

    David

[1] : though obviously it's right for some things such as sshd