Re: udev and dbus

[Greg KH <greg@kroah.com>]

On Wed, Mar 10, 2004 at 05:31:09PM +0100, David Zeuthen wrote:
> 
>  1. Remove dbus support from udev and make udev call /sbin/hotplug with
>     a single positional parameter, 'udev', and the environment variables
>     DEVPATH pointing to the appropriate directory in sysfs, ACTION
>     assuming 'add' respectively 'remove' and DEVICE_FILE pointing to
>     the created / removed special device file.
> 
>     This way, applications, like HAL, interested in the event can simply
>     install a small program in /etc/hotplug.d/[udev,default] to do
>     whatever they want with the event, like sending it to a daemon
>     possibly through what may be the IPC-flavour of the month :-)
> 
>     (yes, this might be abusing the hotplug multiplexor)

Yes, that is abusing the hotplug multiplexor.  I don't like it :)

>  2. Move dbus support from udev to udevd, make sure udevd never
>     exits, and let udevd own the org.kernel.udev service. I guess
>     this would imply building two udevd binaries; one with
>     dbus support and one without (for early boot) and make the small
>     one load the big one upon receiving SIGUSR1. I think Marco
>     d'Itri came up with this approach.

But then udevd would have to know the name that udev created for the
device.  Not good.

>     However, using this approach, we can also offer queries on the
>     udev database using dbus instead of using udevinfo. That would
>     be nice.

How would you do this?  udevinfo does queries, not udevd.

>  3. Remove dbus support and if applications are interested in sending
>     out events using IPC like dbus, they just install a udev callout.
> 
>     I'm not sure this is easy today as all the callout rules are in
>     a single file instead of a directory with rule files. I may be
>     wrong on this though.

Yeah, that would be a "post" type callout.  Again not nice.

My main question is, what is the problem with udev and dbus today?  What
is causing problems?  Is it only on pathilogical systems that don't have
their dbus libraries mounted before udev wants to run?  If so, then tell
those users to fix their systems :)

thanks,

greg k-h


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