Update streams

The XO contacts OLPC on average once a day in order to see if there is a new build which it should be running. Each XO can be subscribed to one of a number of "update streams":

• none - never update me.
• stable - latest stable build
• testing - release candidates or stable upgrade testing
• joyride - not yet implemented, but will someday give you the latest joyride build automatically.

See https://activation.laptop.org/streams/ for the full list.

The stream an XO is subscribed to is determined as follows:

1. If there is a file named /security/update-stream containing a stream name, use it.
2. Otherwise, if there is a file named /etc/olpc-update/update-stream with a stream name, use this. (This is used in joyride builds to ensure the joyride machines are by default subscribed to joyride, not stable.)
3. Otherwise, if the laptop belongs to an 'update group' in OLPC's database, and the update group names a default stream, use it. (This allows us to remotely upgrade XOs in school deployments.)
4. Otherwise, use the default update stream specified by the server, which is currently 'stable'.

Automatic update prevention

In a root shell:

# echo none > /security/update-stream