[Dev] User ID allocation

Piotr Bartosiewicz p.bartosiewi at partner.samsung.com
Thu May 22 16:58:40 GMT 2014

On 22.05.2014 18:14, Thiago Macieira wrote:
> Em qui 22 maio 2014, às 17:59:44, Michal Witanowski escreveu:
>> In the first scenario UID are shifted at the image build time, so after
>> first system boot everything is set up correctly (we don't need any
>> additional shifts here). Migration will be more tricky: firstly we will dump
>> current host image, shift UIDs of file system (by n x 10000) and then flash
>> a minimal Tizen image and install our daemon whose UID will match the one
>> existing in the containers. This is required because of dbus authorization
>> mechanism. If we won't ensure the UID for our demon is free, the
>> communication between the containers will fail.
> >From the original post, the need for having the same UID comes from the fact
> that you're using D-Bus communication to a session bus. The bus daemon
> enforces that all sockets come from processes under the same UID.
> However, that doesn't explain why a system daemon is connecting to a user's
> session bus. That should never happen. Only services inside the session should
> connect to the session bus.
Who wrote that daemon is connecting to a session bus? It's not true!
In our solution we have three complete tizen systems: host system,
first container named private and second container named business.
There is a daemon on the host system which manages containers and
additionally has an ability co communicate with them by connecting to
theirs dbus system sockets (to clarify: there is no connection to session
sockets, there is no connection to host system socket, there are only
two independent connections between host daemon and containers
system dbus).

> In any case, I still don't understand the problem. You're talking about a pair
> of UIDs and flashing the device...

The problem is that we need some user IDs to be the same in the host
tizen as in the container tizen (you can think of them as an independent

Piotr Bartosiewicz
Samsung R&D Institute Poland
Samsung Electronics

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