LightDM - Dec 2015 - normal to have 2 persistant lightdm processes?

Under Ubuntu 14.04 with plain Openbox, lightdm, and
lightdm-gtk-greeter, lxtask shows me 2 lightdm processes all of the
time, whereas I would have expected 1. The output of

ps aux | grep lightdm | grep -v grep

is

root       894  0.0  0.1  35192  3492 ?        SLsl 22:19   0:00 lightdm
root      2766  1.9  1.3  98744 26980 tty7     Ssl+ 22:49   0:45
/usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0
-nolisten tcp vt7 -novtswitch
root      2852  0.0  0.1  19876  3796 ?        Sl   22:49   0:00
lightdm --session-child 12 19

So is that as it should be or have I broken something? If it is as it
should be, maybe you could point me toward something to read on the
topic. Thanks.

Hi,

Yes, it is normal to have two processes.

The first lightdm process is the daemon (PID 894). When you log in, PAM
requires that we start a child process to run the PAM functions inside.
LightDM does this by setting up some pipes to communicate with the daemon
and then re-running itself with --session-child (PID 2852). PAM then (as
root) does whatever it is configured for to authenticate the user and set
up this process to be suitable as your session. Once that is complete we
fork another process, drop permissions and actually run your session. We
need to keep the session child open so when your session ends, we can run
the cleanup process with PAM.

Hope this helps!
--Robert

On Tue, 15 Dec 2015 at 08:04 Plmalternate Plmalternate <
plmalternate at gmail.com> wrote:
> Under Ubuntu 14.04 with plain Openbox, lightdm, and
> lightdm-gtk-greeter, lxtask shows me 2 lightdm processes all of the
> time, whereas I would have expected 1. The output of
>
> ps aux | grep lightdm | grep -v grep
>
> is
>
> root       894  0.0  0.1  35192  3492 ?        SLsl 22:19   0:00 lightdm
> root      2766  1.9  1.3  98744 26980 tty7     Ssl+ 22:49   0:45
> /usr/bin/X -core :0 -seat seat0 -auth /var/run/lightdm/root/:0
> -nolisten tcp vt7 -novtswitch
> root      2852  0.0  0.1  19876  3796 ?        Sl   22:49   0:00
> lightdm --session-child 12 19
>
> So is that as it should be or have I broken something? If it is as it
> should be, maybe you could point me toward something to read on the
> topic. Thanks.
> _______________________________________________
> LightDM mailing list
> LightDM at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/lightdm
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.freedesktop.org/archives/lightdm/attachments/20151214/2cccc915/attachment.html>