[systemd-devel] systemd v4[01] and graphical login managers

[Christian Hesse]

Lennart Poettering <lennart at poettering.net> on Thu, 9 Feb 2012 22:29:38 +0100:
> On Thu, 09.02.12 20:57, Christian Hesse (list at eworm.de) wrote: 
> > > systemd-logind tracks open sessions by keeping open a FIFO fd to the PAM
> > > session client. When the session client dies then systemd will see that
> > > as EOF. Now, if the PAM client side eagerly closes all fds it finds this
> > > will trigger an immediate end of session.
> > 
> > Can I help tracking this down? Let me know what to do.
> 
> Well, strace the PAM client which invokes the PAM session hooks and
> figure out where exactly the fifo is closed and by what piece of
> code. The FIFO fd is received via a dbus reply (which you'll see as a
> recvmsg() with an SCM_RIGHTS param, followed by an fcntl(F_DUPFD)), and
> you'd need to trace where it gets closed in the parent process.

Here is my trace:
http://www.eworm.de/tmp/lightdm.log

I think this is the code closing the fd:
http://bazaar.launchpad.net/~lightdm-team/lightdm/trunk/view/head:/src/pam-session.c#L393
-- 
Best regards,
Chris
                         O< ascii ribbon campaign
                   stop html mail - www.asciiribbon.org