Unable to install printer

Sebastian Roth

@tatanas said in Unable to install printer:

How Fog client checks if a printer is already installed ?

Check out this part of the fog-client code: https://github.com/FOGProject/fog-client/blob/85da019cbd8a939e69fea42779f1bc53b06323cb/Modules/PrinterManager/PrinterManager.cs#L81

Matthieu Jacquart · Fog 1.5.9.138 Debian 11 Vmware ESXi

@tatanas Hi, it looks like same problem I’m facing since few month too, no workaround for now…
https://forums.fogproject.org/topic/15185/problem-mapping-network-printer-after-upgrade-to-1-5-9-60?_=1631803438100
Matthieu

tatanas

@sebastian-roth
Don’t hesitate if you need help debugging.
I’m using the module a lot and this bug is very frustating…

@Matthieu-Jacquart
The bug was there in 1.5.8 too and I think it wasn’t before.

tatanas

So it seems the list “_configuredPrinters” contains the printer that I want to install.
Is it the host’s printers list configured through the fog server web ?
And the “installedPrinters” list will be the printers already installed on the host ?

tatanas

I can understand “…already exists” but what does “… already configured” mean ?

Here is a sample of the log when I try to install a printer which is not already installed on the host :

 22/09/2021 15:58 PrinterManager Adding printers
 22/09/2021 15:58 Printer Adding: B503-LASER (fog)
 22/09/2021 15:59 PrinterManager PrintUI return code = 0
 22/09/2021 15:59 PrinterManager Restarting spooler

...

 22/09/2021 16:02 PrinterManager Adding printers
 22/09/2021 16:02 PrinterManager B503-LASER (fog) has already been configured

...

 22/09/2021 16:04 PrinterManager Adding printers
 22/09/2021 16:04 PrinterManager B503-LASER (fog) has already been configured

I you want, I can give you a remote access to this computer.

tatanas

More details :
I tried adding 2 Fog managed printers and the ports are created (IP_X.X.X.X with the associated IP) but not the printers.
I would say the printui method (even if return code is 0) is not working properly.

Sebastian Roth

@tatanas Finally I found some time to look into this in more depth. Most of the fog-client code came from Joe who is not actively working on this project anymore. While I try to fix things in the fog-client as much as I can I don’t know it well.

As far as I understand things the problem might occour because _configuredPrinters is an internal list the fog-client keeps to know which printer was configured earlier already to skip that on the next loop. But obviously a situation can arise where the rundll32 PrintUI calls return but still the printer is not setup correctly. In that case the fog-client code add it to its internal list of _configuredPrinters and won’t try to configure it until you restart the fog-client service (FOGService in Windows service managment).

So what we need to find out is why this part is not working as it should: https://github.com/FOGProject/fog-client/blob/master/Modules/PrinterManager/Windows/WindowsPrinterManager.cs#L124

tatanas

@sebastian-roth We need detailed log of printui command result.
The command in the client code is the same I have used to test from command line (test was ok), so it’s strange it doesn’t work.

Sebastian Roth

@tatanas Maybe there is some message in the Windows event log? Just a quick idea from the top of my head. I will try to find some time to help you on getting fog-client compiled soon as well.

tatanas

@sebastian-roth I checked Windows event log (spooler log) and didn’t find anything regarding the printer installation.
Thanks for your time.

tatanas

Ok, thanks to you I can build the Fog Client (https://forums.fogproject.org/topic/15757/fog-client-build).
I would like to log the result of the printui command in WindowsPrinterManager.cs at line 41.
I added “> c:\printui.log” but it doesn’t work.

using (var proc = Process.Start("rundll32.exe", $" printui.dll,PrintUIEntry {cmdLine} > c:\\printui.log"))

I don’t know C# so I suppose I could use a method to get Standard Output ?

Sebastian Roth

@tatanas This answer on stackoverflow looks promising: https://stackoverflow.com/a/18529868

tatanas

@sebastian-roth Here are the changes I made in the WindowsPrinterManager.cs at line 41:

using (Process proc = new Process())
{
	proc.StartInfo.FileName = "rundll32.exe";
	proc.StartInfo.Arguments = $" printui.dll,PrintUIEntry {cmdLine}";
        proc.StartInfo.RedirectStandardOutput = true;
	proc.StartInfo.UseShellExecute = false;
	proc.Start();
	var output = proc.StandardOutput.ReadToEnd();
	proc.WaitForExit(30*1000);

        if (proc.HasExited)
        {
              Log.Entry(LogName, "PrintUI return code = " + proc.ExitCode);
	      Log.Entry(LogName, "PrintUI Output = " + output);
        }
        else
        {
              Log.Entry(LogName, "PrintUI has not finished in a timely fashion, abandoning process");
        }
}

replacing

using (var proc = Process.Start("rundll32.exe", $" printui.dll,PrintUIEntry {cmdLine}"))
{
...
}

Unfortunatly, printui does not return anything…

Logging the “cmdLine” variable returns this when the first installation attempts:

cmdLine = /if /b "B503-LASER (fog)" /f "\\@IP_NAS\applications\Imprimantes\HP_LJ_M401\hpcm401u.inf" /r "IP_X.X.X.X" /m "HP LaserJet 400 M401 PCL 6" /q

After that, cmdLine is not used anymore and we’ve got “already configured”.
I never pass in the procedure

public override void Configure(Printer printer, bool verbose = false)
{
...
}

tatanas

I made some tests. The same printui command in local works fine.
So if it’s working in local it should works with fog client which means the added printer is removed/deleted from the host as soon as it’s installed ? It could explain why we can’t see the printer in the host list and why fog client says it’s already configured.

tatanas

Last news :

The script never goes in the “Remove” method, so my last suggestion is wrong.
I made a mistake about the “Configure” method. It is going into this method but it passes into

if (string.IsNullOrEmpty(printer.ConfigFile)) return;

and never execute

PrintUI($"/Sr /n \"{printer.Name}\" /a \"{printer.ConfigFile}\" m f g p", verbose);

EDIT : it is the same behaviour on a computer without problem… I’m lost

Sebastian Roth

@tatanas said in Unable to install printer:

I never pass in the procedure
public override void Configure(Printer printer, bool verbose = false)

Can you please explain what you mean by that?

tatanas

@sebastian-roth Sorry I made a mistake, like I said in my previous post, the “Configure” method is called but does nothing (always enter the second “if”).

tatanas

This problem is very strange.
I was testing on a win7 computer which can’t install printers (fog client 0.12).
I push a old fog image on it and with the same 0.12 client, it now works.
It is not really up to date and the problem appears on win10 too (different version).

Sebastian Roth

@tatanas Maybe the changes that came when MS fixed the printer nightmare issue is causing the problem.

george1421

@sebastian-roth said in Unable to install printer:

Maybe the changes that came when MS fixed the printer nightmare issue

I had to deal with this last week on my campus. (TBH I only skimmed this thread, so this may be a bit off point). The windows accumulative patch for September for both the servers and workstations broke printing for me on the older legacy systems. If you have a currently supported and fully patch version of 2012, 2016, 2019, or what ever is being patched on windows 10 printing worked normally. If you had anything less than 2012 or unpatched win10 or less the users could not print to a current windows print server or install new printers.

It appears in the sept patch MS turned on encrypted communications on the print spooler. I can’t find the article I found at the moment but the workaround is to disable the encryption using the registry key here: https://borncity.com/win/2021/09/20/windows-september-2021-update-workaround-fr-druckprobleme/ Look at the post by Benjamin. I’m not saying this is your problem here with the fog client, but setting this registry value to 0 will allow legacy windows devices to print to contemporary windows print spoolers.

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