Book Image

Mastering Embedded Linux Programming - Third Edition

By : Frank Vasquez, Chris Simmonds
5 (3)
Book Image

Mastering Embedded Linux Programming - Third Edition

5 (3)
By: Frank Vasquez, Chris Simmonds

Overview of this book

If you’re looking for a book that will demystify embedded Linux, then you’ve come to the right place. Mastering Embedded Linux Programming is a fully comprehensive guide that can serve both as means to learn new things or as a handy reference. The first few chapters of this book will break down the fundamental elements that underpin all embedded Linux projects: the toolchain, the bootloader, the kernel, and the root filesystem. After that, you will learn how to create each of these elements from scratch and automate the process using Buildroot and the Yocto Project. As you progress, the book will show you how to implement an effective storage strategy for flash memory chips and install updates to a device remotely once it’s deployed. You’ll also learn about the key aspects of writing code for embedded Linux, such as how to access hardware from apps, the implications of writing multi-threaded code, and techniques to manage memory in an efficient way. The final chapters demonstrate how to debug your code, whether it resides in apps or in the Linux kernel itself. You’ll also cover the different tracers and profilers that are available for Linux so that you can quickly pinpoint any performance bottlenecks in your system. By the end of this Linux book, you’ll be able to create efficient and secure embedded devices using Linux.
Table of Contents (27 chapters)
1
Section 1: Elements of Embedded Linux
10
Section 2: System Architecture and Design Decisions
18
Section 3: Writing Embedded Applications
22
Section 4: Debugging and Optimizing Performance

Using Mender for local updates

So much for the theory. In the next two sections of this chapter, I want to demonstrate how the principles I have talked about so far work in practice. For these examples, I will use Mender. Mender uses a symmetric A/B image update mechanism, with a fallback in the event of a failed update. It can operate in standalone mode for local updates, or in managed mode for OTA updates. I will begin with standalone mode.

Mender is written and supported by mender.io (https://mender.io). There is much more information about the software in the documentation section of the website. I will not delve deeply into the configuration of the software here since my aim is to illustrate the principles of software updates. Let's begin with the Mender client.

Building the Mender client

The Mender client is available as a Yocto meta layer. These examples use the Dunfell release of the Yocto Project, which is the same one that we used in Chapter 6, Selecting a Build...