Switch user incompatible with automatic mounting of media?




I am using Debian Lenny (Testing) with multiple users.  The automatic
mounting of media and SD cards is creating problems.  Is there a
solution, or should this be filed as a bug or suggestion?  I have
searched the Gnome Bugzilla and have not found anything like it.

Usually there are three users signed on, created using the System - Log
Out - Switch User menu item.  We switch back and forth using that menu
item, or more often with <Ctrl><Alt>F7, F8, or F9.

The system has a USB memory card interface.

By default at install time, in System - Preferences - Removable Drives
and Media, the options "Mount removable drives when inserted", "Mount
removable drives when hot-plugged", and "Browse removable media when
inserted" are enabled for all users.

If three users are logged in, and an SD card is inserted in the USB
interface, the system mounts the SD card.  However, the "owner" of the
mounted volume can be any one of the users who is logged in.  If the
"owner" is not the active user (i.e. the one whose desktop is displayed
and is actually using the system) then the active user can't write to
the SD since he doesn't own it.  Nor can he unmount the SD card!  Since
the other user's screens may be locked, he can't switch to their
desktops to unmount either!

Not only that, a Nautilus window for the SD card appears on the desktop
of all the users who are logged in.  If the SD card is unmounted, the
window remains, but its content goes up a level in the directory
hierarchy.  If the SD card is inserted and unmounted multiple times, the
desktops of all the logged in users become cluttered with multiple
Nautilus windows.

I think a similar problem occurs when CDs or DVDs are inserted.

The basic problem here is that there are ambiguities - when the
card/media is inserted it is not clear which user should own the mounted
media, or which desktop will be used to browse it.

The only solution I can see at present is to disable the three options
mentioned above.  But they must be disabled for every possible user,
which is painful.

Possibly the default settings of the three options could be changed so
that they are disabled, although I have not figured out how to do that.

In any case, it seems that significant effort has been put into coding
these options to make the system more user friendly, and to simply
disable them is undesirable.

Is there another solution?  I'd like to know.

If not, here is a suggestion: ---------------

Modify these options so that they are only acted on by an instance of
GDM  IF it is the instance that is active (i.e. visible on the screen)
AND the screen is not locked.  This would eliminate the ambiguity.  The
user who is actually using the system would own the mounted volume, and
would be the only user to see it.


There is a further complication in the case of my system:

This system has two seats.  In addition to the seat described above,
there is a second seat which could have any of the users logged in.

To avoid ambiguity in that situation, an additional condition could be
added, i.e. that if there is more than one active screen that is not
locked, then no action would be taken.

A complete way of dealing with a multi-seat system is probably another
project - e.g. could some devices/USB ports "belong" to one  seat, and
some be shared?

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