This is the code repository for [Mastering Embedded Linux Programming – Third Edition](https://www.packtpub.com/product/mastering-embedded-linux-programming-third-edition/9781789530384?utm_source=github&utm_medium=repository&utm_campaign=9781789530384), published by Packt.
**Create fast and reliable embedded solutions with Linux 5.4 and the Yocto Project 3.1 (Dunfell)**
## What is this book about?
Embedded Linux runs many of the devices we use every day. From smart TVs and Wi-Fi routers to test equipment and industrial controllers, all of them have Linux at their heart. The Linux OS is one of the foundational technologies comprising the core of the Internet of Things (IoT). This book starts by breaking 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.
This book covers the following exciting features:
* Use Buildroot and the Yocto Project to create embedded Linux systems
* Troubleshoot BitBake build failures and streamline your Yocto development workflow
* Update IoT devices securely in the field using Mender or balena
* Prototype peripheral additions by reading schematics, modifying device trees, soldering breakout boards, and probing pins with a logic analyzer
* Interact with hardware without having to write kernel device drivers
If you feel this book is for you, get your [copy](https://www.amazon.com/dp/1789530385) today!
## Instructions and Navigations
All of the code is organized into folders. For example, `Chapter02`.
The code will look like the following:
```
if (test expression)
{
Statement upon condition is true
}
```
**Following is what you need for this book:**
If you’re a systems software engineer or system administrator who wants to learn Linux implementation on embedded devices, then this book is for you. Embedded systems engineers accustomed to programming for low-power microcontrollers can use this book to help make the leap to high-speed systems on chips that can run Linux. Anyone responsible for developing new hardware that needs to run Linux will also find this book useful. Basic working knowledge of the POSIX standard, C programming, and shell scripting is assumed.
With the following software and hardware list you can run all code examples present in the book (Chapter 1-21).
### Software and Hardware List
| Chapters | Software/Hardware Required | OS Required |
| ----------------------------- | --------------------------- | ----------------------------- |
| 3, 4, 5, 6, 9, 11, 12, 15, 21 | BeagleBone Black | Not Applicable |
| 4, 6, 7, 10, 14, 19, 20 | Raspberry Pi 4 | Not Applicable |
| 4, 5, 6 | QEMU (32-bit arm) | Linux (Any) |
| 6, 7, 8, 10, 13, 19, 21 | Yocto Project 3.1 (Dunfell) | Compatible Linux Distribution |
| 6, 12, 13, 14, 19, 20, 21 | Buildroot 2020.02 LTS | Linux (Any) |
| 2, 3, 4, 5 | Crosstool-NG 1.24.0 | Linux (Any) |
| 3, 9 | U-Boot v2021.01 | Linux (Any) |
| 4 | Linux Kernel 5.4 | Linux (Any) |
We also provide a PDF file that has color images of the screenshots/diagrams used in this book. [Click here to download it](http://www.packtpub.com/sites/default/files/downloads/9781789530384_ColorImages.pdf).
## Errata
**Preface**: In the **Download Color Images** section link `https://static.packt-cdn.com/downloads/9781801071000_ColorImages.pdf` _should be_ https://static.packt-cdn.com/downloads/9781789530384_ColorImages.pdf
**Page 18**: The command to install the software required for Chapter 2 is formatted incorectly. There should be a `\` before every newline we wish to escape so that the shell does not execute the command prematurely.
```bash
$ sudo apt-get install autoconf automake bison bzip2 cmake \
flex g++ gawk gcc gettext git gperf help2man libncurses5-dev \
libstdc++6 libtool libtool-bin make patch python3-dev rsync \
texinfo unzip wget xz-utils
```
**Page 28**: The `bin/ct-ng build` command fails for three reasons. First, it cannot download the `isl-0.20` source tarball. Next, it cannot download the `expat-2.2.6` source tarball. Lastly, it cannot compile `binutils` becasue `"error: 'string' in namespace 'std' does not name a type"`. The fix for the first two errors is to download the `isl-0.20` and `expat-2.2.6` source tarballs from different hosts.
```bash
$ cd ~/src
$ wget https://libisl.sourceforge.io/isl-0.20.tar.bz2
$ wget https://github.com/libexpat/libexpat/releases/download/R_2_2_6/expat-2.2.6.tar.bz2
```
The fix for the third error is to insert `#include