3. May 2021

How to add/remove device driver from command-line on Windows

Windows operating system contains a tool that allows manipulation with system drivers stored in .INF and .CAT files. The operation requires Administrator privileges.

Command to install the driver:

pnputil /add-driver my-driver.inf /install

The correct installation display the following result:

Microsoft PnP Utility

Adding driver package:  my-driver.inf
Driver package added successfully.
Published Name:         oem3.inf

Total driver packages:  1
Added driver packages:  1

To verify the result you can plug the device and it should pick the correct driver. The system copied content from my-driver.inf to C:\Windows\INF\oem3.inf. The number in file name might be different.

The remove the driver from the system and perform uninstallation of the driver from devices type following command:

pnputil /remove-driver my-driver.inf /uninstall

Expected result:

Microsoft PnP Utility

Driver package deleted successfully.
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27. April 2021

Quick way to clear all Windows Defender exclusions

Windows Defender has support for a list of exclusions that won’t be considered for scanning. The UI for manipulating with exclusions is quite simple and does not allow operations on multiple exclusions at once. Fortunately, there are PowerShell commands which can help.

These commands are Add-MpPreference, Get-MpPreference, and Remove-MpPreference.

Following commands allows to quickly remove all exclusions of Path. The command must be started in Administrator’s shell:

$Paths=(Get-MpPreference).ExclusionPath
foreach ($Path in $Paths) { Remove-MpPreference -ExclusionPath $Path }

A similar principle can be applied on the rest of the exclusions: ExclusionExtension, ExclusionIpAddress, ExclusionProcess

$Extensions=(Get-MpPreference).ExclusionExtension
foreach ($Extension in $Extensions) { Remove-MpPreference -ExclusionExtension $Extension }

$Processes=(Get-MpPreference).ExclusionProcess
foreach ($Process in $Processes) { Remove-MpPreference -ExclusionProcess $Process }
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22. April 2021

How to run Linux GUI application on Windows WSL2 with MobaXterm and Windows Terminal

MobaXterm is a great software that allows running applications from Linux on Windows in a nice integrated way without the need of installing extra XServer.

MobaXterm has also support for WSL2 which makes it easy to launch Linux GUI applications from Linux on Windows.

After installation of Linux distribution like Ubuntu or openSUSE on WSL2, you will find new sessions with the prefix WSL in MobaXterm. Simply click the session label and a new terminal will be automatically configured to talk to the local XServer.

Now you can start any GUI command, e.g. xeyes.

The same XServer from MobaXterm can be used also from other terminals and shells like Windows Terminal. It’s sufficient to export environment variable DISPLAY in the Linux WSL2 session:

export DISPLAY=127.0.0.1:0.0
xeyes

Note: xeyes are part of x11-apps, you can install them by command

sudo apt install x11-apps
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20. April 2021

How to statically link Rust application for Windows

Rust compiler can generate a single binary that contains all dependencies. This is a great feature for creating stand-alone tools or tools for containers.

There is one gotcha for Windows which does not appear on a developer’s machine. When you move the application to a brand new installation of Windows or you try to start the in Windows Docker Container which contains Windows for Datacenters the app won’t start.

Why? The system is missing Microsoft Visual C++ Redistributable 2015-2019 (vc_redist) which you can download from microsoft.com.

It’s quite inconvenient to force the user to install the package in the case of a stand-alone Rust tool. The package installation even requires elevation of privileges.

The alternative approach to distributing vc_redist is to statically link CRT library into the application. It will result in a slightly bigger application around +100KB.

It’s necessary to tell rustc to perform static linking of CRT.

In the project create file .cargo/config.toml:

[target.x86_64-pc-windows-msvc]
rustflags = ["-C", "target-feature=+crt-static"]

Rebuild the application and the new binary is statically linked and can run even on Windows 8 without vc_redist.

The interesting part is how to determine the proper target name which is on the first line of the example configuration. Many examples on the internet are referring to target.i686-pc-windows-msvc which does not work. Use the following command to determine parts of the name of the target:

rustc --print cfg
target_arch="x86_64"
target_endian="little"
target_env="msvc"
target_family="windows"
target_feature="fxsr"
target_feature="sse"
target_feature="sse2"
target_os="windows"
target_pointer_width="64"
target_vendor="pc"
windows

The target name is composed of values on the lines above.

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19. April 2021

How to do an ICMP ping of a Service in Kubernetes

When moving software to the cloud you may encounter a component that relies on good old ICMP ping.

The problem is that Kubernetes does not support ICMP ping between services. Nigel Poulton described reasons in his post.

But what if the software depends on ICMP ping because it’s hardcoded since days of the pre-cloud era?

One way to solve the problem and make ICMP ping between Service working in Kubernetes is to use the following trick which has two steps:
– open TCP tunnel which forwards a port of service to localhost
– define host alias in /etc/hosts pointing to 127.0.0.1

The trick is based on the simple idea that you can ping localhost and talk to the port with local address which is then forwarded to the desired address.

Commands to add ICMP ping to service “myservice”:

socat tcp-listen:8000,reuseaddr,fork tcp:myservice:8000
echo "127.0.0.1 myservice" >>/etc/hosts

Test:

ping myservice
nc -z myservice 8000

The solution is definitely not 100% bullet-proof, but it can be a good workaround until the software is fixed.

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