book

Embedded Linux Systems with the Yocto Project

by Rudolf J. Streif

May 2016

Intermediate to advanced

480 pages

14h 16m

English

Pearson

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What This Book Is and What It Is NotWho Should Read This BookHow This Book Is OrganizedHands-on Experience

1.1 Why Linux for Embedded Systems?1.2 Embedded Linux Landscape1.2.1 Embedded Linux Distributions1.2.2 Embedded Linux Development Tools1.3 A Custom Linux Distribution—Why Is It Hard?1.4 A Word about Open Source Licensing1.5 Organizations, Relevant Bodies, and Standards1.5.1 The Linux Foundation1.5.2 The Apache Software Foundation1.5.3 Eclipse Foundation1.5.4 Linux Standard Base1.5.5 Consumer Electronics Workgroup1.6 Summary1.7 References
2.1 Jumpstarting Your First Yocto Project Build2.1.1 Prerequisites2.1.2 Obtaining the Yocto Project Tools2.1.3 Setting Up the Build Host2.1.4 Configuring a Build Environment2.1.5 Launching the Build2.1.6 Verifying the Build Results2.1.7 Yocto Project Build Appliance2.2 The Yocto Project Family2.3 A Little Bit of History2.3.1 OpenEmbedded2.3.2 BitBake2.3.3 Poky Linux2.3.4 The Yocto Project2.3.5 The OpenEmbedded and Yocto Project Relationship2.4 Yocto Project Terms2.5 Summary2.6 References
3.1 Building Open Source Software Packages3.1.1 Fetch3.1.2 Extract3.1.3 Patch3.1.4 Configure3.1.5 Build3.1.6 Install3.1.7 Package3.2 OpenEmbedded Workflow3.2.1 Metadata Files3.2.2 Workflow Process Steps3.3 OpenEmbedded Build System Architecture3.3.1 Build System Structure3.3.2 Build Environment Structure3.3.3 Metadata Layer Structure3.4 Summary3.5 References
4.1 Obtaining and Installing BitBake4.1.1 Using a Release Snapshot4.1.2 Cloning the BitBake Development Repository4.1.3 Building and Installing BitBake4.2 Running BitBake4.2.1 BitBake Execution Environment4.2.2 BitBake Command Line4.3 BitBake Metadata4.4 Metadata Syntax4.4.1 Comments4.4.2 Variables4.4.3 Inclusion4.4.4 Inheritance4.4.5 Executable Metadata4.4.6 Metadata Attributes4.4.7 Metadata Name (Key) Expansion4.5 Source Download4.5.1 Using the Fetch Class4.5.2 Fetcher Implementations4.5.3 Mirrors4.6 HelloWorld—BitBake Style4.7 Dependency Handling4.7.1 Provisioning4.7.2 Declaring Dependencies4.7.3 Multiple Providers4.8 Version Selection4.9 Variants4.10 Default Metadata4.10.1 Variables4.10.2 Tasks4.11 Summary4.12 References
5.1 Logging5.1.1 Log Files5.1.2 Using Logging Statements5.2 Task Execution5.2.1 Executing Specific Tasks5.2.2 Task Script Files5.3 Analyzing Metadata5.4 Development Shell5.5 Dependency Graphs5.6 Debugging Layers5.7 Summary
6.1 Linux or GNU/Linux?6.2 Anatomy of a Linux System6.3 Bootloader6.3.1 Role of the Bootloader6.3.2 Linux Bootloaders6.4 Kernel6.4.1 Major Linux Kernel Subsystems6.4.2 Linux Kernel Startup6.5 User Space6.6 Summary6.7 References
7.1 Core Images—Linux Distribution Blueprints7.1.1 Extending a Core Image through Local Configuration7.1.2 Testing Your Image with QEMU7.1.3 Verifying and Comparing Images Using the Build History7.1.4 Extending a Core Image with a Recipe7.1.5 Image Features7.1.6 Package Groups7.2 Building Images from Scratch7.3 Image Options7.3.1 Languages and Locales7.3.2 Package Management7.3.3 Image Size7.3.4 Root Filesystem Types7.3.5 Users, Groups, and Passwords7.3.6 Tweaking the Root Filesystem7.4 Distribution Configuration7.4.1 Standard Distribution Policies7.4.2 Poky Distribution Policy7.4.3 Distribution Features7.4.4 System Manager7.4.5 Default Distribution Setup7.5 External Layers7.6 Hob7.7 Summary
8.1 Recipe Layout and Conventions8.1.1 Recipe Filename8.1.2 Recipe Layout8.1.3 Formatting Guidelines8.2 Writing a New Recipe8.2.1 Establish the Recipe8.2.2 Fetch the Source Code8.2.3 Unpack the Source Code8.2.4 Patch the Source Code8.2.5 Add Licensing Information8.2.6 Configure the Source Code8.2.7 Compile8.2.8 Install the Build Output8.2.9 Setup System Services8.2.10 Package the Build Output8.2.11 Custom Installation Scripts8.2.12 Variants8.3 Recipe Examples8.3.1 C File Software Package8.3.2 Makefile-Based Software Package8.3.3 CMake-Based Software Package8.3.4 GNU Autotools-Based Software Package8.3.5 Externally Built Software Package8.4 Devtool8.4.1 Round-Trip Development Using Devtool8.4.2 Workflow for Existing Recipes8.5 Summary8.6 References
9.1 Kernel Configuration9.1.1 Menu Configuration9.1.2 Configuration Fragments9.2 Kernel Patches9.3 Kernel Recipes9.3.1 Building from a Linux Kernel Tree9.3.2 Building from Yocto Project Kernel Repositories9.4 Out-of-Tree Modules9.4.1 Developing a Kernel Module9.4.2 Creating a Recipe for a Third-Party Module9.4.3 Including the Module with the Root Filesystem9.4.4 Module Autoloading9.5 Device Tree9.6 Summary9.7 References
10.1 Yocto Project BSP Philosophy10.1.1 BSP Dependency Handling10.2 Building with a BSP10.2.1 Building for the BeagleBone10.2.2 External Yocto Project BSP10.3 Inside a Yocto Project BSP10.3.1 License Files10.3.2 Maintainers File10.3.3 README File10.3.4 README.sources File10.3.5 Prebuilt Binaries10.3.6 Layer Configuration File10.3.7 Machine Configuration Files10.3.8 Classes10.3.9 Recipe Files10.4 Creating a Yocto Project BSP10.4.1 Yocto Project BSP Tools10.4.2 Creating a BSP with the Yocto Project BSP Tools10.5 Tuning10.6 Creating Bootable Media Images10.6.1 Creating an Image with Cooked Mode10.6.2 Creating an Image with Raw Mode10.6.3 Kickstart Files10.6.4 Kickstart File Directives10.6.5 Plugins10.6.6 Transferring Images10.7 Summary10.8 References
11.1 Inside a Yocto Project ADT11.2 Setting Up a Yocto Project ADT11.2.1 Building a Toolchain Installer11.2.2 Installing the Toolchain11.2.3 Working with the Toolchain11.2.4 On-Target Execution11.2.5 Remote On-Target Debugging11.3 Building Applications11.3.1 Makefile-Based Applications11.3.2 Autotools-Based Applications11.4 Eclipse Integration11.4.1 Installing the Eclipse IDE11.4.2 Integrating a Yocto Project ADT11.4.3 Developing Applications11.4.4 Deploying, Running, and Testing on the Target11.5 Application Development Using an Emulated Target11.5.1 Preparing for Application Development with QEMU11.5.2 Building an Application and Launching It in QEMU11.6 Summary11.7 References
12.1 Managing Licenses12.1.1 License Tracking12.1.2 Common Licenses12.1.3 Commercially Licensed Packages12.1.4 License Deployment12.1.5 Blacklisting Licenses12.1.6 Providing License Manifest and Texts12.2 Managing Source Code12.3 Summary12.4 References
13.1 Toaster13.1.1 Toaster Operational Modes13.1.2 Toaster Setup13.1.3 Local Toaster Development13.1.4 Toaster Configuration13.1.5 Toaster Production Deployment13.1.6 Toaster Web User Interface13.2 Build History13.2.1 Enabling Build History13.2.2 Configuring Build History13.2.3 Pushing Build History to a Git Repository Server13.2.4 Understanding the Build History13.3 Source Mirrors13.3.1 Using Source Mirrors13.3.2 Setting Up Source Mirrors13.4 Autobuilder13.4.1 Installing Autobuilder13.4.2 Configuring Autobuilder13.5 Summary13.6 References
A.1 MIT License (MIT)A.2 GNU General Public License (GPL) Version 2PreambleTerms and Conditions for Copying, Distribution and ModificationNo WarrantyHow to Apply These Terms to Your New ProgramsA.3 GNU General Public License (GPL) Version 3PreambleTerms and ConditionsHow to Apply These Terms to Your New ProgramsA.4 Apache License Version 2.0TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTIONAPPENDIX: How to Apply the Apache License to Your Work

Content preview from Embedded Linux Systems with the Yocto Project

5. Troubleshooting

In This Chapter

5.1 Logging

5.2 Task Execution

5.3 Analyzing Metadata

5.4 Development Shell

5.5 Dependency Graphs

5.6 Debugging Layers

5.7 Summary

As a software developer, you are well aware that it is never a question of if but when there is an issue with building software. Troubleshooting failures of a complex build system can be a daunting task. Failures can be rooted in many different areas of the build system: the code in recipes and classes, configuration file settings, cross-development, the software package to be built, packaging, and more. It always comes down to

Locating and identifying the cause of the failure, ...