[X2Go-Dev] Bug#1334: Bidirectional clipboard mode stops working with Windows 10 x2goclient

[Aki Ketolainen]

Package: x2goclient
Version: 4.1.2.0

I'm using x2goclient 4.1.2.0 on Windows 10. I have found two ways that
break the bidirectional clipboard mode, one for the MATE desktop and
one for the Plasma 4 desktop (both on the x2go server).

1) MATE desktop

- Open a connection to your x2go server.

- In Windows 10: Open a text editor. I use Notepad++.
- Write a single character in the editor, then select it and use copy.

- In MATE desktop: Open a text editor. I use pluma.
- Press spacebar once and then select the empty space with ctrl+a.
- Use paste to paste the clipboard contents. At this point the
clipboard
functionality breaks.

2) Plasma 4 desktop

- Open a connection to your x2go server.

- In Windows 10: Open a text editor. I use Notepad++.
- Write a single character in the editor, then select it and use copy.

- In Plasma 4 desktop: Open a text editor. I use emacs. If I use KWrite
there is no problem.
- In an empty emacs buffer, press spacebar once, press cursor left and
then use ctrl+space to mark the selection starting point and press
cursor right once to select the empty space.
- Use ctrl+y to yank the contents of the clipboard. At this point
the clipboard functionality breaks and emacs goes into a loop
consuming
100% CPU.

Both of these break the Windows 10 side clipboard so that it doesn't
work
until I restart the computer.

The client machine's OS: Windows 10 64-bit
The client machine's version of X2GoClient, PyHoca-GUI or Pyhoca-CLI:
4.1.20
Any relevant session settings in X2GoClient, PyHoca-GUI or Pyhoca-CLI:
no
The server's OS: MATE desktop: Fedora 27 x86_64, Plasma 4 desktop:
CentOS 6 x86_64
The server's version of the x2goserver package: MATE desktop:
x2goserver-4.1.0.2-0.0x2go1.1.git20180801.1642.main.fc27.x86_64, Plasma
4 desktop: x2goserver-4.0.1.19-3.el6.x86_64
The server's version of the x2goserver-xsession package: MATE desktop:
x2goserver-xsession-4.1.0.2-0.0x2go1.1.git20180801.1642.main.fc27.x86_64,
Plasma 4 desktop: not installed
The server's version of the nxagent package: MATE desktop:
nxagent-3.5.99.16-0.0build1.1.git20180719.2988.main.fc27.x86_64, Plasma
4 desktop: nxagent-3.5.0.32-3.1.x86_64
The server's version of any other relevant packages (e.g., if the bug as
about MATE integration, the version of x2gomatebindings): MATE desktop:
not installed
Any relevant settings in X2GoServer (that you changed from the
defaults): MATE desktop: enabled BIG-REQUESTS

Best regards,

Aki

[Ulrich Sibiller]

Thanks! This sounds a bit like a off-by-one problem in the clipboard code.

However, to break this down further I want to rule out some
components. First, can you please verify if this is somehow
reproducable on a Linux client?

Next I would like to try and take x2go out of the equation:
- run vcxsrv on windows (vcxsrv.exe -multiwindow -ac :121)
- ssh to the Linux server (e.g. with putty) and point the DISPLAY
variable to the VcXsrv on windows (export
DISPLAY=:<windowsmachine>:121) Note: you might have to disable the
windows firewall
- run nxagent -ac :123 in the shell on the server -> you will get the
nxagent window on you Windows desktop
- in a second shell on the server point the DISPLAY variable to :123
and start the MATE session (export DISPLAY=:123;
STARTUP=mate-session dbus-run-session /etc/X11/Xsession)
Now repeat your editor tests.

Uli

Post by Aki Ketolainen
Package: x2goclient
Version: 4.1.2.0
I'm using x2goclient 4.1.2.0 on Windows 10. I have found two ways that
break the bidirectional clipboard mode, one for the MATE desktop and
one for the Plasma 4 desktop (both on the x2go server).
1) MATE desktop
- Open a connection to your x2go server.
- In Windows 10: Open a text editor. I use Notepad++.
- Write a single character in the editor, then select it and use copy.
- In MATE desktop: Open a text editor. I use pluma.
- Press spacebar once and then select the empty space with ctrl+a.
- Use paste to paste the clipboard contents. At this point the
clipboard
functionality breaks.
2) Plasma 4 desktop
- Open a connection to your x2go server.
- In Windows 10: Open a text editor. I use Notepad++.
- Write a single character in the editor, then select it and use copy.
- In Plasma 4 desktop: Open a text editor. I use emacs. If I use KWrite
there is no problem.
- In an empty emacs buffer, press spacebar once, press cursor left and
then use ctrl+space to mark the selection starting point and press
cursor right once to select the empty space.
- Use ctrl+y to yank the contents of the clipboard. At this point
the clipboard functionality breaks and emacs goes into a loop
consuming
100% CPU.
Both of these break the Windows 10 side clipboard so that it doesn't
work
until I restart the computer.
The client machine's OS: Windows 10 64-bit
4.1.20
no
CentOS 6 x86_64
x2goserver-4.1.0.2-0.0x2go1.1.git20180801.1642.main.fc27.x86_64, Plasma
4 desktop: x2goserver-4.0.1.19-3.el6.x86_64
x2goserver-xsession-4.1.0.2-0.0x2go1.1.git20180801.1642.main.fc27.x86_64,
Plasma 4 desktop: not installed
nxagent-3.5.99.16-0.0build1.1.git20180719.2988.main.fc27.x86_64, Plasma
4 desktop: nxagent-3.5.0.32-3.1.x86_64
The server's version of any other relevant packages (e.g., if the bug as
not installed
Any relevant settings in X2GoServer (that you changed from the
defaults): MATE desktop: enabled BIG-REQUESTS
Best regards,
Aki
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[Aki Ketolainen]

Package: x2goclient
Version: 4.1.2.0

Post by Ulrich Sibiller
Thanks! This sounds a bit like a off-by-one problem in the clipboard code.
However, to break this down further I want to rule out some
components. First, can you please verify if this is somehow
reproducable on a Linux client?

The bidirectional clipboard mode doesn't break with the Linux
x2goclient,
in either MATE desktop or Plasma 4 desktop. I'm using x2goclient
v4.1.1.1
on Fedora 27 client machine.

Post by Ulrich Sibiller
- run vcxsrv on windows (vcxsrv.exe -multiwindow -ac :121)
- ssh to the Linux server (e.g. with putty) and point the DISPLAY
variable to the VcXsrv on windows (export
DISPLAY=:<windowsmachine>:121)
Note: you might have to disable the windows firewall
- run nxagent -ac :123 in the shell on the server -> you will get the
nxagent window on you Windows desktop
- in a second shell on the server point the DISPLAY variable to :123
and start the MATE session (export DISPLAY=:123;
STARTUP=mate-session dbus-run-session /etc/X11/Xsession)
Now repeat your editor tests.
Uli

I used PuTTY's X11 forwarding/tunneling to do this. The bidirectional
clipboard mode breaks in the same way with this method in both MATE
desktop and Plasma 4 desktop.

Best regards,

Aki

[Aki Ketolainen]

I tested x2goclient with mobaxterm too. With it the bidirectional
clipboard
mode keeps on working, it just doesn't support that case that you've
selected a single space in your x2go server's text editor and try to
paste
on top of it.

I tested this in Windows 8 and there was no rdpclip.exe process running.

Best regards,

Aki