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

Applying a patch


For cases where we need to apply a patch to an existing package, we should use FILESEXTRAPATHS, which includes new directories in the searching algorithm, making the extra file visible to BitBake, as shown here:

FILESEXTRAPATHS_prepend := "${THISDIR}/${PN}-${PV}:"
SRC_URI += "file://mypatch.patch"

In the preceding example, THISDIR expands to the current directory, and PN and PV expand to the package name and package version, respectively. This new path is then included in the directories list used for file searching. The use of the _prepend operator is important as it guarantees that our provided file is used, even if a file with the same name is added in the lower priority layers in future.

BitBake assumes that every file with a .patch extension is a patch and applies them accordingly.