Re: ownership of devices

[Martin P Holland <nospam [at] noether.freeserve.co.uk>]

Thanks for your message Stephen. I'm finding this quite interesting; I hope
everyone else is too :-)

On Fri, 27 Aug 1999, Stephen wrote:

>Well, this shouldn't happen at login; that is broken design.

Nod.

>It
>should be done when a request is made to the kernel to use a device
>service. (I don't know that that is possible using kmod, although
>kerneld can do anything; still in theory.) There should also be a
>service whereby a client can grab a device, and reserve it for own
>use, presumably with a timeout.

Well it seems to me that RH aren't putting their faith in kmod. I noticed that
the RH rc.sysinit script doesn't trust kmod to load the sounds stuff and loads
it manually with modeprobe at boot time. I'm not sure what for. Perhaps they're
gearing up for audio boot messages: Sound modules failed to load correctly
that sort of thing.

> Martin> After all my only other user is jacqui and she knows the
> Martin> root password anyhow.
>
>In that situation you could just chmod a+rw all the audio, fb, and
>removable block devices.

Ha if only! Well I don't really want to do this anyway but my experience of
changing permissions in dev is that RH in nanny mode resets the permissions.
E.g. if I login as martin, chmod 666 /dev/dsp, (hey I own it!) and then logout
again then it's back to it 600 state when I login again. Actually I guess if you
are going to give martin ownership of /dev/dsp then you had better make sure
you clean up any mess he might cause. So perhaps this ownership thing and
the permissions reset are connected. I wonder if it would recreate /dev/dsp if
I deleted it? It certainly doesn't reset permissions with all the devices
because it is tolerating the change in permissions I gave to my modem device
/dev/ttyS1

>I would prefer figuring out how to make it
>work as intended, but (even though I suspect in principle you feel
>that way too) it sounds like that's not a priority for you right now.

I do have limited energy for this at the moment but I would be interested
to know a bit more about this. However, since I haven't
seen anyone else complain about this on usenet maybe the redhat developers
won't feel hard-pressed to change things from the way they are now.

> Martin> Strangely although martin owns the floppy device this
> Martin> doesn't seem to stop jacqui reading and writing to it. So
> Martin> that isn't broken. It just seems to be the sound that
> Martin> doesn't play well, if you excuse the pun.
>
>Probably the permissions on the floppy device allow everybody to read
>and write (see above). Mounting will probably depend on the
>permissions of the /dev directory as well as the floppy mount point.

So what was the point of chowning the /dev/fd0 /dev/fd0D360 /dev/fd0D720 /dev/fd0H1440 /dev/fd0H360 /dev/fd0H720 /dev/fd0d360 /dev/fd0h1200 /dev/fd0h360 /dev/fd0h720 /dev/fd1 /dev/fd1D360 /dev/fd1D720 /dev/fd1H1440 /dev/fd1H360 /dev/fd1H720 /dev/fd1d360 /dev/fd1h1200 /dev/fd1h360 /dev/fd1h720

> Martin> Well I may give it a go when I play at home networking
> Martin> (when funds permit).
>
>Even in Japan, funding a HAN only requires giving up beer (or orange
>juice) for a week. ;-) Go for it! (Assuming you've got two desktop
>boxes; PCMCIA cards are still expensive :-( ).

It's the second box :-)

[snip useful info about debian]

Thanks for that.

atb
Martin
--
http://www.shef.ac.uk/~pm1mph

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