Linux interactive agent asks to install/update Zenity while it is already there

[Yvan-Masson]

Hi,

Thanks again for all the work you do.

I am running MeshCentral 0.6.99. I tried to use the interactive agent on a Ubuntu 20.04 laptop today, but it failed saying The graphical version of this installer cannot run on this system. Try installing/updating Zenity, and run again. I checked and Zenity was installed (3.32.0-5).

I tried to run the same interactive agent in an Ubuntu 20.04 live image, and it works properly. Any idea why it failed on this particular laptop? Sorry I am really bad at reading .js… I don't have this laptop at home but can do a few tests in the following days if needed.

[krayon007]

From a terminal window on your laptop, can you run the following two commands wherever your agent is installed, and let me know the result?

./meshagent -exec "console.log(require('message-box').zenity);process.exit();"

./meshagent -exec "console.log(require('message-box').zenity.extra);process.exit();"

[krayon007]

If the second command returns false, I suspect your Linux system is configured to use wayland. If that's the case you need to do the following 3 things:

1. Open /etc/gdm/custom.conf or /etc/gdm3/custom.conf
2. Uncomment: WaylandEnable=false.
3. Add the following line to the [daemon] section:
   DefaultSession=gnome-xorg.desktop

[krayon007]

If the previous suggestion corrects your issue, I'll add a check for this, so that it gives you a better suggested solution.

[Yvan-Masson]

Thanks Bryan for the answer.

I ran these two commands and both fail with this message:

The graphical version of this installer cannot run on this system.
Try installing/updating Zenity, and run again.

You can also run the text version from the command line with the following command(s): 
./meshcentral -connect

I double checked, the session does not run with Wayland (and indeed, running ./meshagent -connect works perfectly). Also, just to confirm, I run zenity myself on this computer for personal scripts so it is properly installed and working.

[krayon007]

Ok sorry, I meant run it with the agent, not the installer...
But you can run the commands on the installer too, if you add the --no-embedded=1 switch at the end... So try running these two commands for me, and tell me the result:

./meshcentral -exec "console.log(require('message-box').zenity);process.exit();" --no-embedded=1
./meshcentral -exec "console.log(require('message-box').zenity.extra);process.exit();" --no-embedded=1

[krayon007]

You're not connected to your linux machine via an SSH session are you? I have Ubuntu 20 running with the same version of zenity... The only way this should fail, is if the agent can't find the xserver instance for the current session.

[Yvan-Masson]

Thanks for your answer. The commands I previously ran was with the interactive agent, not the installer.
Here is the output of the last commands you gave me:

./meshcentral -exec "console.log(require('message-box').zenity);process.exit();" --no-embedded=1
{ path: /usr/bin/zenity, timeout: false }

./meshcentral -exec "console.log(require('message-box').zenity.extra);process.exit();" --no-embedded=1
false

I always logged normally, not via SSH. I just checked, $DISPLAY has the usual value :0.

[krayon007]

Ok, how about this command:
./meshcentral -exec "try{var u=require('user-sessions').consoleUid();var x=require('monitor-info').getXInfo(u);console.log(x);}catch(e){console.log(e);}process.exit();" --no-embedded=1

[Yvan-Masson]

Sorry for the delay, I have been quite busy and the computer where there is this issue is no easily reachable.

Your last command returns nobody logged into console. Note that I tried this command with server and corresponding interactive agent in versions 0.7.9, 0.7.10 and 0.7.14.

[krayon007]

if you just run the command: who what does it return?

[Yvan-Masson]

You are right, who does not return anything (but return code is 0)… I notice that /var/run/utmp and /var/run/wtmp are missing, I will have to investigate. I suppose who is expected to return something: you could just change the error message for this particular case, or you can state that this issue should never arise :-)

Anyway, thanks for your work on debugging this issue, I am sorry the problem was on my side.

Regards,
Yvan

[krayon007]

You are right, who does not return anything (but return code is 0)… I notice that /var/run/utmp and /var/run/wtmp are missing, I will have to investigate. I suppose who is expected to return something: you could just change the error message for this particular case, or you can state that this issue should never arise :-)

Anyway, thanks for your work on debugging this issue, I am sorry the problem was on my side.

Regards,
Yvan

Interesting... I do remember Puppy Linux behaves similarly, as it doesn't return anything for 'who', among a few other oddities... I had some work-arounds for Puppy Linux around this for a few other things, but I don't think I ran the binary installer on Puppy Linux, so I'll take a look at that when I get back...

[krayon007]

You are right, who does not return anything (but return code is 0)… I notice that /var/run/utmp and /var/run/wtmp are missing, I will have to investigate. I suppose who is expected to return something: you could just change the error message for this particular case, or you can state that this issue should never arise :-)

Anyway, thanks for your work on debugging this issue, I am sorry the problem was on my side.

Regards,
Yvan

ok, I just cofirmed Puppy Linux does almost the exact same thing... It gives the same error message.. Altho in puppy linux's case, who doesn't exist, which is what I used to work around this issue for other use cases. (But I didn't for the binary installer)...

In your case tho, you said who exists, it just doesn't return anything... But you said /var/run/utmp is also missing... This is the same with Puppy Linux, so I will probably include this in the work-around... I'll do testing with Puppy Linux, and send you something you can test on your system when I get it working.

[krayon007]

On a side note, is your ubuntu system configured with no users? Puppy linux essentially does not have any users, as when you power it on, you are automatically logged in as a root user. This is why /var/run/utmp is missing and who doesn't exist on Puppy Linux.

[Yvan-Masson]

I forgot about Puppy Linux's existence :-)

I can not tell why this Ubuntu computer has this weirdness, I think I installed it in a very classical manner (i.e. with the graphical installer) and did not configure anything fancy on it. Do no hesitate to ask if you want me to do some test.

[krayon007]

Did you set up Ubuntu to autologin? Or do you actually have to specify a username/password to login?

[krayon007]

did you do a clean install or an upgrade of your ubuntu machine? From what I can tell online, it looks like there used to be a bug in systemd, that caused this issue during an OS update. But it looked like you could just manually create utmp and wtmp, to restore functionality.

[Yvan-Masson]

I think I did a clean install of this computer. But indeed, autologin might be enabled, I will have to check, probably only next week…

[Yvan-Masson]

In case you are interested in this strange Ubuntu issue, I spent some time on it without success. Autologin was indeed enabled. I can create /var/run/utmp with proper owner/group/permissions but it is deleted on each reboot, even if I disable autologin in lightdm. I also had a very quick look to systemctl status systemd-update-utmp.service and it seems to be OK. I have no other idea right now.

Feel free to close this issue as this computer's issue seems to be very uncommon and might not deserve a workaround in the mesh agent…