GDM failsafe session query

[Roger Burroughes <roger inf ed ac uk>]

Folks,

	I have a question about failsafe sessions when a user's home
directory isn't available (for whatever reason). I've been trying to
track down what happens (or doesn't happen), but without much
success...

	When a user starts logging-in via GDM using the standard
greeter (and assuming there is no home directory available for this
user - everything works OK when it IS available), a warning message is
displayed:

   "Your home directory is listed as:
    '/home/infteach'
    but it does not appear to exist.
    Do you want to log in with the root
    directory as your home directory?

    It is unlikely anything else will work unless
    you use a failsafe session"

	(This message is displayed even when a failsafe session is
explicitly selected from the "Session" menu.) 

	Selecting "Yes" (I'd like a failsafe session please) from the
warning message dialogue box just returns you to the "Username:"
prompt in the login window (Quiver=true is set in gdm.conf - and it
doesn't quiver - so this, plus the fact that it gets to the point of
LOOKING for a home directory, makes me think that authentication is
OK).

	I'm assuming that it SHOULD be possible to login with a
failsafe session in these circumstances (no home directory), but I
can't find out where it's failing. It must fail fairly early on, as
it's not even trying to run /etc/X11/gdm/Xsession (no
/tmp/xses-infteach is created).

	The "home directory... does not appear to exist" message comes
from daemon/slave.c - but this contains nearly 4,000 lines of code,
and my C-debugging skills are, alas, somewhat limited.

	Does anybody have any pointers or clues as to what's happening
here? Once gdm-binary has called gdmlogin, what is the next in line to
be called? Or could my problem be within gdmlogin? (Although I have
looked at what documentation I can find, I couldn't see an execution
path for the various components of a successful login.)


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Roger Burroughes				| University of Edinburgh
Phone:	+44 (0)131 650 4447                     | School of Informatics
Fax:	+44 (0)131 650 4587			| 2 Buccleuch Place
Email:  R Burroughes ed ac uk                   | Edinburgh EH8 9LW Scotland
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