Asking the user to mount a device

[Martin Pitt]

Hello Brennan,

Brennan Vincent [2009-09-07 23:41 -0700]:
> I have two partitions on my hard drive: one containing Ubuntu and the
> other containing Vista. The Vista partition is called "OS". It is not
> mounted on boot, but it appears in the Gnome "Places" menu. When
> clicked, the user is asked to grant root privileges in order to mount
> the device in the proper place (/media/OS).
> 
> My question is: what is the mechanism for this? 

In Karmic it works roughly like this:

 * All storage devices are detected by the Kernel, and put into /sys.
   Look at /sys/block/*. This also contains the information whether a
   device is removable or fixed.

 * udev reads /sys and imports these devices into its database. It
   also does some probing to find out the file system, partition type,
   etc. Look at /lib/udev/rules.d/60-persistent-storage.rules and
   /lib/udev/rules.d/95-devkit-disks.rules

   http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev.html

 * GNOME, in particular gvfs, reads the udev database and creates
   "volumes" for them: "gvfs-mount -li" displays the status
   This is what appears in the places menu.

 * When you try to mount a device, gvfs contacts DeviceKit-disks over
   D-Bus (since mounting needs root, it can't do it itself), and
   DK-disks does the mount into /media, either by label or by UUID.

   http://hal.freedesktop.org/docs/DeviceKit-disks/

In Ubuntu 9.04 and below, the udev/devicekit-disks part was done by
"Hal", but that's being deprecated now.

Martin
-- 
Martin Pitt                        | http://www.piware.de
Ubuntu Developer (www.ubuntu.com)  | Debian Developer  (www.debian.org)