Re: [gdm-list] Face recognition for linux login ...

[José Miguel Buenaposada Biencinto <josemiguel buenaposada urjc es>]

First of all, forgive me for answering so late :-(.

Thanks for your advice .... it works!!!

JM.


Brian Cameron wrote:

>
> José:
>
> All gdm GUI's run as the "gdm" user (refer to User/Group settings
> in the GDM configuration).  The default values are gdm:gdm.
>
> Note that GDM saves it's Xauthority cookies in /var/lib/gdm
> (some distros may modify the servauthdir directory, but this is
> the normal default for most distros so you shouldn't hardcode
> this directory and make it configurable for your PAM module).
> So you should be able to grab the Xauth cookie from here.  I
> believe the file named .cookie is the cookie that the root user
> can use when GDM is showing the GUI.
>
> Since your PAM module code should be running as root, grabbing
> and using the Xauth key for the gdm user should be possible to
> do.
>
> I hope this helps.  Let me know.
>
> Brian
>
>> First of all I have to introduce myself, I'm a Computer Vision
>> researcher interested in human computer interaction. And
>> I apologize if this is a bit off-topic (although it could not be).
>>
>> Some time ago I asked for advice in the gdm-list about
>> implementing face recognition for linux login on gdm:
>>
>> http://mail.gnome.org/archives/gdm-list/2004-September/msg00001.html
>>
>> And Bob Doolittle sugested to implement such a thing as a PAM module:
>>
>> http://mail.gnome.org/archives/gdm-list/2004-September/msg00016.html
>>
>> Anyhow, we are now developing the face recognition driven linux login
>> (on a master thesis) using a PAM module. The problem we have now is
>> how to deal with the Xserver security (when using Xauthority) in
>> order to show
>> a graphical window with the video aside the gdm login window.
>>
>> What we are doing is to fork a process in the PAM module to run
>> the face recognition loop on the the child process. And when we try
>> to show
>> a simple graphical window the X server don't allow us to connect ... we
>> are not even logged into the system and we are not using the rigth
>> Xauthority
>> magic cookie !!
>>
>> And the question is, what is the unix user from which the gdm is
>> running?
>> what can we do to launch a window from a process aside the gdm login
>> window?
>>
>> Please, answer me directly as I'm not in the list.
>>
>> Many thanks for any advice.
>> Jose M. Buenaposada.
>>
>