running LightDM in test mode doesn't work

[iGadget]

As described on https://wiki.ubuntu.com/LightDM, I should be able to run lightdm --test-mode in a console. However, when I try that, I first get this error:

matthijs@Simba:~$ lightdm --test-mode
Running inside an X server requires Xephyr to be installed but it cannot be found. Please install it or update your PATH environment variable.

When I then install the xserver-xephyr package and try again, a small window opens for less than a second and then closes again. No errors, no testing environment. Nothing.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: lightdm 0.9.7-0ubuntu2
ProcVersionSignature: Ubuntu 3.0.0-11.18-generic 3.0.4
Uname: Linux 3.0.0-11-generic x86_64
ApportVersion: 1.23-0ubuntu1
Architecture: amd64
Date: Mon Sep 26 22:01:52 2011
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Alpha amd64 (20110803.1)
SourcePackage: lightdm
UpgradeStatus: Upgraded to oneiric on 2011-09-22 (3 days ago)

[iGadget (igadget)]

This is the output of lightdm --test-mode --debug:

matthijs@Simba:~$ lightdm --test-mode --debug
** (lightdm:5521): DEBUG: Logging to /home/matthijs/.cache/lightdm/log/lightdm.log
** (lightdm:5521): DEBUG: Starting Light Display Manager 0.9.7, UID=1000 PID=5521
** (lightdm:5521): DEBUG: Loaded configuration from /etc/lightdm/lightdm.conf
** (lightdm:5521): DEBUG: Using D-Bus name org.freedesktop.DisplayManager
** (lightdm:5521): DEBUG: Running in user mode
** (lightdm:5521): DEBUG: Using Xephyr for X servers
** (lightdm:5521): DEBUG: Registered seat module xlocal
** (lightdm:5521): DEBUG: Registered seat module xremote
** (lightdm:5521): DEBUG: Adding default seat
** (lightdm:5521): DEBUG: Starting seat
** (lightdm:5521): DEBUG: Starting new display for greeter
** (lightdm:5521): DEBUG: Starting local X display
** (lightdm:5521): DEBUG: Logging to /home/matthijs/.cache/lightdm/log/:1.log
** (lightdm:5521): DEBUG: Writing X server authority to /home/matthijs/.cache/lightdm/run/root/:1
** (lightdm:5521): DEBUG: Launching X Server
** (lightdm:5521): DEBUG: Launching process 5525: DISPLAY=:0 XAUTHORITY=/home/matthijs/.Xauthority /usr/bin/Xephyr :1 -auth /home/matthijs/.cache/lightdm/run/root/:1 -nolisten tcp
** (lightdm:5521): DEBUG: Waiting for ready signal from X server :1
** (lightdm:5521): DEBUG: Acquired bus name
** (lightdm:5521): DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0
** (lightdm:5521): DEBUG: Got signal 10 from process 5525
** (lightdm:5521): DEBUG: Got signal from X server :1
** (lightdm:5521): DEBUG: Connecting to XServer :1
** (lightdm:5521): DEBUG: Starting greeter session
** (lightdm:5521): DEBUG: pam_start("lightdm", "matthijs") -> (0x20ed930, 0)
** (lightdm:5521): DEBUG: Starting session lightdm-gtk-greeter as user matthijs logging to /home/matthijs/.cache/lightdm/log/:1-greeter.log
** (lightdm:5521): DEBUG: Launching session
** (lightdm:5521): DEBUG: PAM returns environment ''
** (lightdm:5521): DEBUG: Adding session authority to /home/matthijs/.Xauthority (written in session process)
** (lightdm:5521): DEBUG: Launching process 5527: LIGHTDM_FROM_SERVER_FD=16 DISPLAY=:1 HOME=/home/matthijs XDG_SESSION_COOKIE=ed87da5adc4c91b5ec47fcd60228ac83-1317064036.211475-1584743962 GDMSESSION=lightdm-gtk-greeter DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-PH8ngJ2MiL,guid=d399fa3ba164838dd0471e5c00000037 LIGHTDM_TO_SERVER_FD=19 LDM_BUS=SESSION USERNAME=matthijs XAUTHORITY=/home/matthijs/.Xauthority DESKTOP_SESSION=lightdm-gtk-greeter USER=matthijs PATH=/usr/lib/lightdm/lightdm:/usr/local/bin:/usr/bin:/bin SHELL=/bin/bash /usr/lib/lightdm/lightdm-greeter-session 'lightdm-gtk-greeter'
** (lightdm:5521): DEBUG: Process 5527 exited with return value 0
** (lightdm:5521): DEBUG: Greeter quit
** (lightdm:5521): DEBUG: Stopping display
** (lightdm:5521): DEBUG: Sending signal 15 to process 5525
** (lightdm:5521): DEBUG: Removing session authority from /home/matthijs/.Xauthority
** (lightdm:5521): DEBUG: Process 5525 exited with return value 0
** (lightdm:5521): DEBUG: X server stopped
** (lightdm:5521): DEBUG: Removing X server authority /home/matthijs/.cache/lightdm/run/root/:1
** (lightdm:5521): DEBUG: Displ...

[Jason Conti (jconti)]

The greeters were moved to /usr/sbin but the PATH only contains /usr/lib/lightdm/lightdm:/usr/local/bin:/usr/bin:/bin. They used to be in libexecdir which is manually added to the path in session.c:session_start.

The greeter log at ~/.cache/lightdm/log/:1-greeter.log contains:

exec: 33: lightdm-gtk-greeter: not found

which is from /usr/lib/lightdm/lightdm-greeter-session. As a workaround until this is fixed, adding /usr/sbin to PATH before the exec on line 33 in that file will allow the greeter to start.

This isn't an issue when lightdm runs normally because /usr/sbin is part of the environment received from pam, but some of the setup is skipped in the --test-mode session, and in the log above the pam environment is empty.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Robert Ancell (robert-ancell)]

Fixed in 0.9.9

[Launchpad Janitor (janitor)]

This bug was fixed in the package lightdm - 1.0.0-0ubuntu1

---------------
lightdm (1.0.0-0ubuntu1) oneiric; urgency=low

  [ Steve Langasek ]
  * don't start on graphics-device-added; reintroducing this reverted the fix
    for bug #615549 from maverick without explanation.
  * clean up the completely illegible start rule for debian/lightdm.upstart,
    killing off the unnecessary parentheses
  * debian/lightdm.upstart: when lightdm is shut down by a runlevel call,
    emit an upstart event that can be caught by plymouth so it can
    distinguish between the DM shutting down for a runlevel change vs. other
    causes. LP: #854329.

  [ Robert Ancell ]
  * New upstream release.
    [ 0.9.8 ]
    - GetSeatForCookie and GetSessionForCookie are now deprecated. They
      remain for now but use the XDG_SEAT_PATH and XDG_SESSION_PATH
      environment variables instead.
    - Change log filenames to be unique across different display types.
    - Fix up script hooks, add regression tests for them
    - Complete removal of X code from the core of LightDM, so it can better
      support various display types
    - Add ability to set the language of a user from the greeter (LP: #803858)
    - Set LANG variable based on the user language
    - Add language selector into GTK greeter (disabled by default)
    - Allow TCP/IP connections if xserver-allow-tcp is true
    - Allow lightdm --version to be run as non-root
    - Automatically respond to PAM messages without prompts (LP: #783598)
    - Create 'AddLocalXSeat' D-Bus method, and require root to use 'AddSeat'
    - Fix multi-seat configuration picking the same display number (LP: #851362)
    - Use correct D-Bus and power interface in liblightdm-qt (LP: #852803)
    - Run pam_setcred inside the session process so pam_group works
      (LP: #851347)
    - Make sure one session is always selected in the GTK greeter (LP: #819177)
    [ 1.0.0 ]
    - Explicitly grab keyboard focus in GTK greeter
    - Fix removed power and a11y menu items in GTK greeter
    - Put system binary directory into path when running in test mode
      (LP: #860003)
    - Call pam_getenvlist after pam_setcred

  [ Lionel Le Folgoc ]
  * Make the gtk greeter easily themable by derivatives: (LP: #845549)
    - rename lightdm-gtk-greeter.conf to lightdm-gtk-greeter-ubuntu.conf,
      and handle the move in maintainer scripts.
    - manage /etc/lightdm/lightdm-gtk-greeter.conf with update-alternatives,
      by default it uses /etc/lightdm/lightdm-gtk-greeter-ubuntu.conf with a
      very low priority.
  * debian/control: lightdm-gtk-greeter provides lightdm-gtk-greeter-config.
 -- Robert Ancell <email address hidden> Wed, 28 Sep 2011 16:00:20 +1000

[Zsolt Lauter (lauterzsolti)]

Got exactly the same.

 L ~ : lightdm --test-mode
Running inside an X server requires Xephyr to be installed but it cannot be found. Please install it or update your PATH environment variable.
 L ~ : cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=15.10
DISTRIB_CODENAME=wily
DISTRIB_DESCRIPTION="Ubuntu 15.10"