GNOME Breakability Issues -- options and actions breaking Gnome and Sugar

[martin.langhoff]

From field reports, when Gnome is available

• Users delete or rename ~/Activities, rendering Sugar unusable
• Users disable networking in nm-applet, and Sugar does not re-enable it
• Users push GNOME config settings until GNOME is unusable
• Users place files in random places

We may split these into subitems.

[greenfeld]

I had the idea to set the Activities, etc., directories read only if not immutable (via chattr or similar) whenever a user switches from Sugar to Gnome, and release the restriction when they switch from Gnome to Sugar.

Martin likes this but had the further idea of doing this from olpc-session depending on which Window manager it decides to start. Personally I wonder if the latter will cause unnecessary delays and/or SD card writing.

Chattr might be a better way of doing this if we're concerned activities like controlling the permissions of certain files in their directories. I seriously doubt many of them use chattr to do it as it would confuse most people when removing items.

[Quozl]

Interesting, but ... the controls you are all suggesting (protecting or hiding) are also available with the user-id barrier. Why not place the GNOME and Sugar environments in different usernames? What use case is there for sharing files between the two environments that can't be satisfied by other means?

Moving /home/olpc/Activities to some other location for the duration of a GNOME session should not create any significant delay or SD card writing. Only one file, the directory, moves. A move is not atomic, contrary to popular belief, but the ext3 journal should take care of power loss during move. In olpc-session execution next time, the directory will have been either moved or not moved.

[greenfeld]

I thought of using two different users as well; but that was considered undesirable since children/teachers may want to share content between Sugar and GNOME.

Some light usage of SElinux or similar also could work too.

[Quozl]

Again, I ask, if learners and teachers may want to share content between Sugar and GNOME, how on earth are they going to do it? There's no filesystem access in Sugar, there's no Journal access in GNOME. What sharing method is documented for teachers? And if content is shared, will sharing across a protective directory boundary (/home/olpc vs /home/gnome) be any harder?

[greenfeld]

I presume that those in favor of not using two separate users are planning for a future where GNOME and Sugar can share items to an extent with a single user. Teachers in some deployments supposedly are taught to use USB sticks, which bypasses this entire issue.

A two-user approach might also factor into those deployments that are trying to have multiple users use one laptop. (Perhaps Sugar eventually will have a login manager.)

In any case, we could divide this into long-term and short-term fixes, although changing the two-user fix into a one-user approach could be a bit of a pain.

A quick kludge with two users to allow sharing between Sugar and Gnome could be to add a new icon for an external mounted "drive" which really was a setgid dropbox directory. GNOME could then point to that with a folder shortcut.

[martin.langhoff]

Right now, there is no user-friendly way to share files within the system; true. But a gnome-vfs plugin that allows access to the Journal is within reach.

If we separate users, it does become a whole lot harder down the road. And separating users this late in the cycle is a large undertaking.

[godiard]

I didn't tried yet, but this http://git.sugarlabs.org/datastore-fuse can solve the sharing files between Sugar and Gnome.