Issues while creating thinlinc sessions

ThinLinc
1

Hello,
We recently install thinlinc 4.14.0 version on Ubuntu 20.04 for one of our customer.
When the customer tries to connect to the server using the thinlinc client it gives error

No LSB modules are available.
--- End system information ---
Cannot find xsri. Background image support not available.
Running /opt/thinlinc/etc/xstartup.d/01-set-display.sh (make the DISPLAY environment variable include the hostname)
Running /opt/thinlinc/etc/xstartup.d/01-tl-kinit.sh (Obtaining Kerberos ticket)
/opt/thinlinc/libexec/xprop failed: stderr:
/opt/thinlinc/libexec/xprop:  unable to open display 'thinlinc01.abc.com:10'

Unable to fetch SSO attribute TL_SENSITIVE_PARAMS
/opt/thinlinc/libexec/xprop failed: stderr:
/opt/thinlinc/libexec/xprop:  unable to open display 'thinlinc01.abc.com:10'

Unable to fetch SSO attribute TL_SENSITIVE_PARAMS
Running /opt/thinlinc/etc/xstartup.d/02-set-xhost.sh (allow X11 connections from all hosts)
xhost:  unable to open display "thinlinc01.abc.com:10"
Running /opt/thinlinc/etc/xstartup.d/02-tl-dbus-launch.sh (Starting session D-Bus server)
Existing session D-Bus server found.
Setting initial D-Bus and systemd environment...
Running /opt/thinlinc/etc/xstartup.d/11-tl-set-title (Setting client window title)
Running /opt/thinlinc/etc/xstartup.d/12-tl-default-keyboard (Configuring default keyboard layout)
Setting default keyboard layout to "us(alt-intl)"
Cannot open display "thinlinc01.abc.com:10"
Running /opt/thinlinc/etc/xstartup.d/15-tl-shadow-notify (Enabling notifications when the session is shadowed)
Can't open display: thinlinc01.abc.com:10
Running /opt/thinlinc/etc/xstartup.d/20-tl-select-profile.sh (Choosing a profile)
Running /opt/thinlinc/etc/xstartup.d/30-tl-xdg-user-dirs (Translating standard folders)
Running /opt/thinlinc/etc/xstartup.d/40-tl-mount-localdrives (Mounting local drives)
Running /opt/thinlinc/etc/xstartup.d/41-tl-lp-redir-launch (Setting up printer port redirection)
Unable to open DISPLAY, exiting ...
Running /opt/thinlinc/etc/xstartup.d/43-tl-pulseaudio-launch.sh (Starting session PulseAudio server)
Unable to open DISPLAY, exiting ...
Failed to start session PulseAudio server
Running /opt/thinlinc/etc/xstartup.d/50-tl-wait-smartcard (Waiting for smart card connection)
Stopping initial window manager...

Thu Jan 19 12:29:52 2023
 Connections: accepted: 127.0.0.1::59980
Openbox-Message: Failed to open the display from the DISPLAY environment variable.
 SConnection: Client needs protocol version 3.8
Done.
 SConnection: Client requests security type VncAuth(2)
 VNCSConnST:  Replacing existing connection
 VNCSConnST:  Server default pixel format depth 24 (32bpp) little-endian rgb888
Executing profile: xfce
Using XDG session: xfce
Updating D-Bus and systemd environment...
Executing XDG session command: startxfce4
/bin/startxfce4: X server already running on display thinlinc01.abc.com:10
xrdb: Connection refused
xrdb: Can't open display 'thinlinc01.abc.com:10'
Unable to init server: Could not connect: Connection refused
xfce4-session: Cannot open display: .
Type 'xfce4-session --help' for usage.
Profile command exited with exit code 1
Running /opt/thinlinc/etc/xlogout.d/tl-kdestroy.sh
kdestroy: No credentials cache found while destroying cache
Running /opt/thinlinc/etc/xlogout.d/tl-log-rotation.sh
Running /opt/thinlinc/etc/xlogout.d/tl-umount-localdrives
tl-xinit: client terminated and returned 0
tl-xinit: Terminating X server...
X connection to :10 broken (explicit kill or server shutdown).^M
 VNCSConnST:  closing 127.0.0.1::59980: Server shutdown
 EncodeManager: Framebuffer updates: 1
 EncodeManager:   Tight:
 EncodeManager:     Solid: 4 rects, 786.272 kpixels
 EncodeManager:            64 B (1:49142.8 ratio)
 EncodeManager:     Indexed RLE: 1 rects, 160 pixels
 EncodeManager:                  85 B (1:7.67059 ratio)
 EncodeManager:   Total: 5 rects, 786.432 kpixels
 EncodeManager:          149 B (1:21112.7 ratio)
 ComparingUpdateTracker: 0 pixels in / 0 pixels out
 ComparingUpdateTracker: (1:-nan ratio)
tl-xinit: X server has terminated
tl-xinit: deleting ../10.1674125836.ended
tl-xinit: Session terminated. Exiting.

When we manually setup the DISPLAY to :10 it works then but not when it gets set via 01-set-display.sh script which thinlinc provides which sets DISPLAY to {HOSTNAME}{DISPLAY}

Can you please help out here ?

2

Hello,

Neither /opt/thinlinc/etc/xstartup.d/01-set-display.sh or /opt/thinlinc/etc/xstartup.d/02-set-xhost.sh is something that ships with ThinLinc 4.14.0, so this must be some custom modifications made by someone else, which we know little about.

Regards,
Martin

3

Hi we were facing the exact issue which was described in [Thinlinc-technical] Export DISPLAY into Thinlinc session. And the idea of 01-set-display.sh was proposed there.
By default right now the DISPLAY gets assigned to :10 when we login to thinlinc server using the the thinlinc client . Now, when i login to different server from the thinlinc server via ssh there DISPLAY variable gets exported as :10 too and xclock or xeyes don’t work there.

How can i fix or achieve this ?

4

Hello,

Ok, I see.
That solution was proposed by another ThinLinc user, and is not something that is officially from us. Is there any special reason why you would like to do it that way? A lot has changed since that post from 2015, and I don’t think Xvnc listens to tcp anymore.

Could a better approach be to use X11 Forwarding (i.e., ssh -X)?

Kind regards,
Martin

5

Not by default since ThinLinc 4.10. Relevant bug:

https://bugzilla.cendio.com/show_bug.cgi?id=7350