Book Image

Embedded Linux Development using Yocto Projects - Second Edition

By : Otavio Salvador, Daiane Angolini
Book Image

Embedded Linux Development using Yocto Projects - Second Edition

By: Otavio Salvador, Daiane Angolini

Overview of this book

Yocto Project is turning out to be the best integration framework for creating reliable embedded Linux projects. It has the edge over other frameworks because of its features such as less development time and improved reliability and robustness. Embedded Linux Development using Yocto Project starts with an in-depth explanation of all Yocto Project tools, to help you perform different Linux-based tasks. The book then moves on to in-depth explanations of Poky and BitBake. It also includes some practical use cases for building a Linux subsystem project using Yocto Project tools available for embedded Linux. The book also covers topics such as SDK, recipetool, and others. By the end of the book, you will have learned how to generate and run an image for real hardware boards and will have gained hands-on experience at building efficient Linux systems using Yocto Project.
Table of Contents (22 chapters)
Title Page
Credits
About the Authors
About the Reviewer
www.PacktPub.com
Customer Feedback
Preface
7
Diving into BitBake Metadata
Index

Using metadata


The amount of metadata used by BitBake is enormous. To get the maximum benefit out of using Poky, we must master it. As we learned in Chapter 4, Grasping the BitBake Tool, metadata can be classified into the following three major areas:

  • Configuration (the .conf files): Configuration files define the global content that is used to provide information and configure how the classes and recipes will work
  • Classes (the .bbclass files): Classes are available to the whole system and can be inherited by recipes to easily maintain and avoid code duplication
  • Recipes (the .bb or .bbappend files): The recipes describe the tasks to be run and provide the required information to allow BitBake to generate the required task chain. They are the most commonly used type of metadata as they are where we put it all at work. The most common types of recipes generate packages and images.

The classes and recipes are written in a mix of Python and shell scripting code. When a recipe is executed by BitBake...