Thoughts about HAL, Ivman and Pmount.

Artem Kachitchkine Artem.Kachitchkin at Sun.COM
Thu Oct 27 15:17:56 PDT 2005

> How do you mean external? But if automounting is done on system level
> (not user session), for example by ivman running as ivman.plugdev,
> shouldn't ivman set the correct ownership (like "ivman.plugdev" and then
> let all users who should be able to access and unmount media be part of
> the "plugdev" group)

A device must belong to somebody. It should probably belong to root by 
default. Root can take permanent ownership of the device and mount it so 
it's accessible to all. There's nothing preventing you from running 
root's instance of a volume manager outside any root session.

> It doesn't work if all users log into the box trough X terminals. (the
> console isn't used by any user)

It all comes down to the question of device ownership. Unfortunately, 
there isn't a universal algorithm to associate X terminals with devices( 
although there are heuristics, but they don't work for everyone). So the 
sysadmin needs to associate devices with users through another policy, 
such as multiseat.conf. It's true that currently HAL and volume managers 
are not particularly multiuser-friendly, and it's a problem. But the 
problem can't be solved entirely within HAL.

>>This should be
>>fixed by a mufy ownership policy and a mufy volume manager. I'm
>>working on a HAL extension to make this easier to implement, but
>>that's just one piece of the puzzle.
> Sounds interesting, would you like to tell more about this?

Sure, see:

>>It's kind of a stretch to compare these two. HAL is a system-wide 
>>service with system-wide settings. Volume managers such as g-v-m and 
>>ivman are user applications with per-user settings.
> But ivman has double functions, it's also used as a system service with
> system settings.
> (It's then running as ivman.plugdev and using /etc/ivman/*.xml config
> files)

I'm inclined to look at it as belonging to one of the users - root.

> But maybe I should get a better volume manager instead?

I was alluding to that :)


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