[Dev] Tizen 3.0 proposal for fixing OSP/WRT/Core hard-coded UID issue

Jussi Laako jussi.laako at linux.intel.com
Thu Oct 17 08:42:17 GMT 2013

On 17.10.2013 10:28, Łukasz Stelmach wrote:
> FWIW, there is no such thing as X11 session. X11 is just a display
> server (almost) everyone can connect to.

Well, nitpicking, xdm initiates sessions when you login locally or 
remotely through port 6000. I still remember running one single Linux 
server and having number of X11 terminals connecting to it for user 
sessions, for example HP's 9000-series X11 terminal with Intel i960 CPU 
and Windows machines with WinaXe (http://www.labf.com/winaxe/).

Or more generally, to cover X11 over rsh/rlogin/ssh anything with a 
separate session id/tty and having independent DISPLAY environment set.

> Last time I talked to Lenart Pottering, he was aiming the model I've
> described with his systemd-logind. First time user logs in a session is
> started and it is closed when the last shell dies. The only problem I
> can see here is: is it possible to heave more than one active seat?

Somehow I always get upset when I hear that name. First pulseaudio cuts 
number of corners and now systemd. Oh well, that just breaks things that 
traditionally used to work on Unix.

Of course there shouldn't be any limit how many sessions/seats a single 
user can have simultaneously. It is completely normal for me to have a 
local session open on desktop 24/365 and then I randomly login to from 
various places over ssh or xdm and run applications. When application 
fires up services from the remote login I expect dialogs related to that 
session to appear on that seat. With normal DISPLAY environment and 
dbus-daemon --session started as part of login with random bus address 
this works just fine.

Those services who expect to have exclusive access to something in $HOME 
are broken by design and probably also misbehave in multithreaded 
environment too and thus cannot exploit benefits of parallelism. 
Databases support basic locking and transactions.

> I havn't myself too. However, I've heard Gnome, for example, does have
> some problems running in more than one session for the same user (I've
> heard the issues are because of the way some information is stored and
> shared in ~/.gnome* directories, I havn't seen it myself)

Most of the things go through either gconf or sqlite and neither should 
have as such problems with multi-access when used correctly.

Anyway, this is going off-topic. For Tizen we just need to define if 
this is generally supported case or not. What is more important feature 
is possibility to transfer sessions between seats.

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