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Re: CD burning without root priviligdes



On Wednesday 13 November 2002 12:28, Frank Van Damme wrote:
> On Wednesday 13 November 2002 03:48, Carlos Carvalho wrote:
> > I'm glad to finally see a discussion of this subject. I find the
> > structure of CD recording software in Linux quite outdated and
> > inadequate for a multi-user environment (note that this isn't a KDE
> > problem). The software was clearly conceived to be used by someone
> > with root access sitting on the console of the machine, which is
> > almost the opposite of what is necessary for a CD-recorder server.
> 
> It's ugly allright... but why does writing cd's need root privilegies? Isn't 
> it an inadequacy in the kernel?
> 
> > I'd like to have something similar to what we have for scanners: a
> > daemon (that may run as root if necessary) waiting for connections
> > through the net and operating the device, or interfacing with a
> > driver. The user interacts remotely with a client software (of course
> > the user may via localhost as well). This approach has many
> > advantages:
> 
> Oh no... not another daemon... 

If you hate daemons: How about a program started via hotplug(?) when
a cd is inserted? >;-)

> > a) it removes permissions problems from the scene;
> > b) no need for authentication of users, because it's not the user that
> >    has access, it's the daemon. Access to the daemon is controlled by
> >    standard methods (firewall, tcp wrappers, etc.);
> 
> Er, maybe. You mean because the daemon runs as root? Then it just places the 
> permission problem somewhere else: with the daemon. There should always be a 
> way to go without daemons in any case (if you're just using the writer
> locally).

Right but a daemon is much more flexible how do deal with authorization and access
rights.   Having to logout/in from/to X session to activate new group group member ship
is something like rebooting Windoof after every software installation.  Stupid but necessary
(and no:  su/ssh etc is no good solution of Mum and Dad).   I'm really curious
what solution the debian desktop project will develop.
 
> > c) it allows the use of the recorder by users in other machines. This
> >    way we can have a diskless machine with just a recorder and users
> >    connect from a login server via the client software. I have here a
> >    scanner connected to such a machine that also controls the printers
> >    and works as a X-term, while the login server remains locked in
> >    another room and users reach it from X-terminals.

yes, yes please ;)
> 
> Let me guess: ltsp addon? :-)
> 
> The only thing I can think of that currently comes close is webcdrwriter. It's 
> a java applet client-side and a daemon that operates cdrecord server-side.
> 
> > I use this approach for CD readers, floppy drives, scanners,
> > printers, zip drives, but I cannot do it for CD recorders :-( :-(
> 
> Floppy drives? without mounting them on the server you mean? how? 

with floppy:/a and mtools one can work with floppies without mounting them.
And for remote access:

ds10[1] ~ # apt-cache search floppyd
floppyd - Daemon for remote access to floppy drives
> 
> (I burned a few floppy controllers a while ago)
> 
> > I understand that cdrecord and family were written at a time when
> > recording a CD was a delicate operation. However with the fast
> > machines and network of today the picture has changed completely, and
> > it seems to me that a revamp is really necessary. In the process we
> > could perhaps get rid of scsi emulation...
> 
> Uh-oh... and now comes the argumentation "today, we all have pretty big 
> machines so we can afford to make an overhead-producing  daemon :-/
> I like cdrecord for its power, flexibility, performance, stability and low 
> system requirements. Maybe it's better to remove the need for root 
> privilegies completely (what is a multiuser system worth if you have to do 
> anything that's useful with root privilegies?) Maybe cdrecord doesn't need to 
> get trashed, it may be just enough to make it run as a client of that fancy 
> daemon you're intending to code :-) in a way like now gui clients use 
> cdrecord.
> 
>     /----------------\     /----------\    /--------\
> So: | $kde*cd*burner |=--->| cdrecord |=-->| kernel |
>     \----------------/     \----------/    \--------/
> 
>                  ||
>                  \/
>     /----------------\     /------------\     /----------\     /--------\
>     | $kde_cd_burner |=--->| netCDaemon |=--->| cdrecord |=--->| kernel |   
>     \----------------/     \------------/     \----------/     \--------/
> 
> 
> btw, I think freebsd already writes cds without scsi emulation isn't it?

linux > 2.5.44 can do it.  http://linux.bkbits.net:8080/linux-2.5/ChangeSet@..1.786.1.22?nav=index.html|tags

torvalds
1.781.29.3
Remove ide-cd reliance on "struct packet_struct", make it use
the native "struct request" fields instead.
    
Simplify and clean up sense data handling.

This makes IDE CD-RW burning possible without ide-scsi.c

> > The same strategy is used in the Network Audio System (NAS) developed
> > by NCD and available in the libaudio-dev package. Next is the camera :-)
> 
> Artsd has network transpareency doesn't it?

Yes, but I could not come up with good solution to run artsd on an X-terminal.

artsd -> nas daemon is also possible but when I tried ( ~ 1 year ago) the output
was horrible.  Same sample played several time with a time offset.  that was
on a 100mb switched network).    Does NAS work for someone?  Worth to try
again?
> 
> > Any volunteers? :-)
> 
> Within a few months maybe ;-)

please s/maybe//  :)

Achim
> 
> Frank
> 
> 
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> 

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