Raymii.org

Hi there!

I'm Remy, a developer from The Netherlands with a focus on C++, C, some C#, Linux and embedded systems.

I currently work on a C++ and Qt stack running on Yocto Linux. It controls hardware, runs the UI and has a few utilities for IoT connectivity and configuration. Technologies I'm fluid in include C, C# & C++, Windows (MFC/Win32), .NET (Core, Xaml, Framework and C++/CLI), Flash, Qt, Ansible, Bash & PowerShell. I was Linux and UNIX sysadmin for over 10 years before I got into development.

To read more or get in touch, click here. This is my personal website, these articles do not reflect or are based on work, opinions or policies of any of my (previous) employers. Any resemblance to reality is pure coincidence.

Latest Items

My go-to C++ code for asynchronous work processing on a separate thread

You probably recognise this situation. You're working on your code and realise that the thing you're writing might take long, be blocking or is batch-wise. It might be resizing images, calling some API or processing hardware inputs or a stream of incoming messages. These tasks, if not handled efficiently, can halt your application, leaving it unresponsive. To avoid this, one solution is to offload these time-consuming operations to a separate thread, allowing the main application to continue executing without interruptions. In this article, I'll show you how you can implement asynchronous work processing in C++ using a worker thread. This example class is my go-to for this situation and is easily adapted to handle more complex use cases. It has a queue of work items and uses a std::thread, a std::mutex combined with a std::condition_variable to manage work asynchronously, processing items one by one.

The Adventure of the Missing Syscall: Error 38

Sherlock Holmes tackles a modern computing dilemma involving a missing system call. In this case, a frustrated developer attempts to port an embedded device running Yocto to a newer version, only to be met with Error 38 due to a missing syscall. Holmes and Watson delve into the intricacies of kernel versions, glibc, and system calls to uncover the truth behind the missing syscall_397 and provide a logical solution.

Logging all C++ destructors, poor mans run-time tracing

I recently faced a challenging issue with an application that wasn't shutting down correctly, either segfaulting or terminating without an active exception. Running the program via valgrind to check for memory leaks wasn't possible because the program couldn’t perform its cleanup if it didn't shut down correctly. This article covers adding runtime instrumentation provided by gcc to log destructors. This helped me figure out what was still left over from the closed-source framework in use preventing correct shutdowns or causing segfaults. It includes example code, setup instructions and insights into handling shutdown issues in large, multi-threaded codebases.

Compiling TETRIS from 1992 on OpenVMS x86 in 2024!

Since DECWindows / CDE now works on OpenVMS x86 (from 9.2-3 onwards) there is much fun stuff to do. Back in 2021 I wrote an article on the CDE desktop on Alpha / AXPbox and also an article on how to run CDE on modern linux, since it's still developed. Both articles included a game, GENERIC-TETRIS from 1992, written by Qiang Alex Zhao. After getting the (remote) desktop working I wanted to compile and run Tetris to continue this lineage, from VAX, to Alpha, to Linux/CDE, to x86 VMS. I haven't got an Itanium to run it on, but if anyone has one left willing to send this way, feel free to contact me. This article includes the precompiled tetris binary for OpenVMS x86 and instructions to compile the source. The code required some minor modifications which I'll also cover, but that's not surprising for code that hasn't changed much since 1992 to be compiled in 2024. This article also shows you how to install curl on OpenVMS.

OpenVMS x86 E9.2-3 fixes CDE (DECWindows) and adds a Guest Console (no serial port required anymore)

I'm a big fan of OpenVMS. You can read all my OpenVMS articles here. Since the licensing changes to the Hobbyist Program, I applied and was included in to the Ambassador Program. A new update of the X86 field test is released and this includes to major changes for hobbyists. One is a new feature, the Guest Console, which makes installing easier by no longer requiring a serial port and fiddling with Putty or your telnet client and the second is a fix to the C/C++ compiler which, (probably by accident), fixes CDE and DECWindows. The Common Desktop Environment (CDE) is still under development and can be installed on Linux quite easily. This post shows the two new features, the Guest Console and CDE working.

OpenVMS 9.2 for x86, Getting Started part 1, install guide with VirtualBox

OpenVMS on x86 is now available for hobbyists! Almost a year after the official release. This is a part 1 of my getting started guide, showing you how to install OpenVMS on VirtualBox on Windows 10/11. More parts will follow, documenting license installation, network setup, ssh, application installation etc.

Create Kubernetes user restricted to one namespace with resource limits

This guide shows you how to use Role-based access control (RBAC) to create a user account that only has rights for one specific namespace. I'll also show you how to limit the resource usage of that Namespace. Last but not least, I'll also show you how to create a kubeconfig file for that specific user.

nameConstraints on your Self Signed Root CA in Kubernetes with cert-manager

If you have set up a Self Signed Root CA for your local Kubernetes Cluster and have trusted the Root Certificate, you are at risk if the key is compromised. If the key is stolen, it can be used to create trusted certificates for everything. Luckily there is something we can do, using nameConstraints to limit the scope of the Root Certificate to, in our case, a single domain (k3s.homelab.mydomain.org). This means that if your key would be compromised, it would only be able to issue certificates for anything under that domain, not your bank for example.

Self-signed Root CA in Kubernetes with k3s, cert-manager and traefik. Bonus howto on regular certificates

Now that I'm learning Kubernetes for a few weeks, I'm finally at the point where I was 20 years ago with regular boring old tech, being able to host multiple domains, password protection and high available clusters. It seems we have to re-invent the wheel every time but in the end, it's just resume-driven development, the underlying stack costs more, is way more complex but for the user, nothing changes, they see the same website as always. Not all change is progress. Enough of being a curmudgeon, time to continue with Kubernetes. In this episode of 'Remy discovers Kubernetes', I'm setting up cert-manager, not with Lets Encrypt, but with a self-signed certificate authority. I'll also show you how to set up a regular certificate, one you've for example bought somewhere. I'll also cover nameConstraints to make the risk of compromise of your trusted root ca lower.

OpenSSL get entire certificate chain from a domain or loop over entire chain in file

The openssl x509 command can be used to get information from a certificate. If you supply a filename, the command will only use the topmost certificate in the file, not all certificates in the file, like in the case of a certificate chain. The openssl s_client -connect command can connect to a server and show all certificates served by that server. The command I'm providing in this snippet splits up all certificates found in a file or as the result of openssl s_client and allows openssl x509 to loop over each one individually.

Password protect web services in Kubernetes (k3s/traefik) with basic auth

Now that I have a high-available local kubernetes cluster and am experimenting with deploying apps, it's also time to look into securing those apps using certificates and passwords. In this case I'm going to set up password authentication, like a .htaccess file in Apache2, to protect the Longhorn dashboad, which by default requires no authentication. This means deploying an Ingress, a Middleware and a Secret.

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