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

What should be in the root filesystem?

The kernel will get a root filesystem, either as an initramfs passed as a pointer from the bootloader or by mounting the block device given on the kernel command line by the root= parameter. Once it has a root filesystem, the kernel will execute the first program, by default named init, as described in the Early user space section in Chapter 4, Configuring and Building the Kernel. Then, as far as the kernel is concerned, its job is complete. It is up to the init program to begin starting other programs and bring the system to life.

To make a minimal root filesystem, you need these components:

  • init: This is the program that starts everything off, usually by running a series of scripts. I will describe how init works in much more detail in Chapter 13, Starting Up – The init Program.
  • Shell: You need a shell to give you a command prompt but, more importantly, also to run the shell scripts called by init and other programs.
  • ...