[LightDM] can't connect to display before login

[Alfonso Fiore]

Hello Robert and thank you.

a user at ubuntuforums.org suggests an other way:

http://ubuntuforums.org/showthread.php?t=1860295

create a file /etc/init/x11vnc.conf which does:

start on login-session-start
script
/usr/bin/x11vnc -auth /var/run/lightdm/root/:0 -noxrecord -noxfixes
-noxdamage -rfbauth /etc/x11vnc.pass -forever -bg -rfbport 5900 -o
/var/log/x11vnc.log
end script

and it works!

Thanks a lot for the support!

On Mon, Oct 24, 2011 at 10:51 PM, Robert Ancell <robert.ancell at gmail.com>wrote:

> Hi Alfonso,
>
> display-setup-script is run once the X server starts and before anyone
> logs in.  session-setup-script is run before a session is started.
>
> Set:
> [SeatDefaults]
> display-setup-script=/my/script
>
> And set /my/script to :
> sudo /usr/bin/x11vnc -noxrecord -noxfixes -noxdamage -rfbauth
> /etc/x11vnc.pass -forever -bg -rfbport 5900 -o > /tmp/x11vnc.log
>
> Should do the trick (haven't tested it myself).
>
> On 19 October 2011 14:51, Alfonso Fiore <alfonso.fiore at gmail.com> wrote:
> > hi guys,
> > it took quite some reading (actually a lot of bad reading and very little
> > good reading in the log of x11vnc) but I found a solution.
> > Simply I needed to find and use the raw display manager MIT-MAGIC-COOKIE
> as
> > per x11vnc logfile:
> > ===============================================
> > ** If NO ONE is logged into an X session yet, but there is a greeter
> login
> >    program like "gdm", "kdm", "xdm", or "dtlogin" running, you will need
> >    to find and use the raw display manager MIT-MAGIC-COOKIE file.
> > Sometimes the command "ps wwwwaux | grep auth" can reveal the file
> location.
> > ===============================================
> > which lead me to the right command:
> > sudo /usr/bin/x11vnc -auth /var/run/lightdm/root/:0 -noxrecord -noxfixes
> > -noxdamage -rfbauth /etc/x11vnc.pass -forever -bg -rfbport 5900 -o
> > /tmp/x11vnc.log
> > only one question: do you know if lightDM offers a way to run this
> command
> > once lightDM has finished loading?
> > Thank you,
> > alfonso
> > On Wed, Oct 19, 2011 at 1:26 AM, Alfonso Fiore <alfonso.fiore at gmail.com>
> > wrote:
> >>
> >> Hi Robert, Guido,
> >> thank you.
> >> Indeed the log file was a smart idea ;-)
> >> I found quite a telling line there:
> >> [+0.01s] WARNING: Can't start VNC server, Xvn is not in the path
> >> in fact I used x11vnc and I didn't have any Xvnc installed.
> >> So you were all correct, but I still didn't manage :(
> >> I tried installing tightvncserver but I got access to a new session, but
> >> instead I'm looking to enable desktop sharing. I tried for a good hour
> to
> >> find how to share the main desktop with tightvnc and then I gave up.
> >> So I tried also installing vnc4server which has some problem regarding
> >> authentication. I get an error in my client: "no password configured for
> vnc
> >> auth" but also I wasn't capable to debug this either. It has probably to
> do
> >> with pam, but I didn't manage to debug the issue:
> >> lightdm.log:[+0.90s] DEBUG: pam_start("lightdm-autologin", "lightdm") ->
> >> (0x8bef588, 0)
> >> lightdm.log:[+0.90s] DEBUG: pam_authenticate(0x8bef588, 0) -> 0
> (Success)
> >> lightdm.log:[+0.90s] DEBUG: pam_acct_mgmt(0x8bef588, 0) -> 0 (Success)
> >> lightdm.log:[+0.91s] DEBUG: pam_set_item(0x8bef588, 3, ":0") -> 0
> >> (Success)
> >> lightdm.log:[+0.92s] DEBUG: pam_open_session(0x8bef588, 0) -> 0
> (Success)
> >> lightdm.log:[+0.95s] DEBUG: pam_setcred(0x8bef588, PAM_ESTABLISH_CRED)
> ->
> >> 0 (Success)
> >> lightdm.log:[+1.50s] DEBUG: pam_start("lightdm", "alfonso") ->
> (0x8c06588,
> >> 0)
> >> I see Xvnc is started as /usr/bin/Xvnc :6 -auth /var/run/lightdm/root/:6
> >> -inetd -nolisten tcp but I don't see the -rfbauth to point to the
> password
> >> file. Is there a chance to manually add such option?
> >> If I run for example "Xvnc :0 -rfbauth /etc/x11vnc.pass" directly at
> >> prompt I can authenticate but still I don't get to share the main
> desktop.
> >> I also tried to create a symbolic link from x11vnc to Xvnc since I know
> >> x11vnc works fine, but since x11vnc doesn't have options for running
> with
> >> inetd, it didn't work.
> >> Incidentally, at least in Ubuntu 11.10, /var/log/lightdm has
> >> permissions drwxr-xr-x but lightdm tries to create log files there with
> >> user lightdm and fails. So I had to change permissions to 777.
> >> e.g.
> >> [+246.83s] WARNING: Failed to open log file
> >> /var/log/lightdm/xvnc-6-greeter.log: Permission denied
> >> Actually, kind of bad news...
> >> From
> >> here:
> http://grumpymole.blogspot.com/2006/12/xubuntu-remote-desktop-with-vnc4server.html?showComment=1167878940000#c1198657880206490449
> >> I gather that only x11vnc can share the desktop (is it true?)
> >> This is what I'm trying to achieve. Any chance lightdm can support
> x11vnc
> >> as well?
> >> Thank you.
> >> Good night,
> >> alfonso
> >> On Wed, Oct 19, 2011 at 12:11 AM, Robert Ancell <
> robert.ancell at gmail.com>
> >> wrote:
> >>>
> >>> There are multiple Xvnc servers available on Ubuntu, the
> >>> tightvncserver package contains one.
> >>>
> >>> On 19 October 2011 09:08, Guido Berhoerster <gber at opensuse.org> wrote:
> >>> > * Alfonso Fiore <alfonso.fiore at gmail.com> [2011-10-18 23:44]:
> >>> >> Hello Guido,
> >>> >>
> >>> >> thank you so much. It sounds great.
> >>> >>
> >>> >> Now my /etc/lightdm/lightdm.conf looks like:
> >>> >>
> >>> >> [SeatDefaults]
> >>> >> greeter-session=unity-greeter
> >>> >> user-session=ubuntu
> >>> >>
> >>> >> [VNCServer]
> >>> >> enabled=true
> >>> >> port=5900
> >>> >>
> >>> >> but after restarting lightdm (sudo restart lightdm) the port is not
> >>> >> open:
> >>> >>
> >>> >> dude at box:~$ netstat -ln | grep 5900
> >>> >> dude at box:~$
> >>> >>
> >>> >> I also tried to reboot, but the result is the same.
> >>> >>
> >>> >> do you have any suggestion? maybe some missing package?
> >>> >
> >>> > Do you have Xvnc installed? I don't know what package it's in
> >>> > since I don't use Ubuntu.
> >>> > --
> >>> > Guido Berhoerster
> >>> > _______________________________________________
> >>> > LightDM mailing list
> >>> > LightDM at lists.freedesktop.org
> >>> > http://lists.freedesktop.org/mailman/listinfo/lightdm
> >>> >
> >>
> >
> >
> > _______________________________________________
> > LightDM mailing list
> > LightDM at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/lightdm
> >
> >
>
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