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Mastering Embedded Linux Programming - Third Edition

You're reading from  Mastering Embedded Linux Programming - Third Edition

Product type Book
Published in May 2021
Publisher Packt
ISBN-13 9781789530384
Pages 758 pages
Edition 3rd Edition
Languages
Authors (2):
Frank Vasquez Frank Vasquez
Profile icon Frank Vasquez
Chris Simmonds Chris Simmonds
Profile icon Chris Simmonds
View More author details

Table of Contents (27) Chapters

Preface Section 1: Elements of Embedded Linux
Chapter 1: Starting Out Chapter 2: Learning about Toolchains Chapter 3: All about Bootloaders Chapter 4: Configuring and Building the Kernel Chapter 5: Building a Root Filesystem Chapter 6: Selecting a Build System Chapter 7: Developing with Yocto Chapter 8: Yocto Under the Hood Section 2: System Architecture and Design Decisions
Chapter 9: Creating a Storage Strategy Chapter 10: Updating Software in the Field Chapter 11: Interfacing with Device Drivers Chapter 12: Prototyping with Breakout Boards Chapter 13: Starting Up – The init Program Chapter 14: Starting with BusyBox runit Chapter 15: Managing Power Section 3: Writing Embedded Applications
Chapter 16: Packaging Python Chapter 17: Learning about Processes and Threads Chapter 18: Managing Memory Section 4: Debugging and Optimizing Performance
Chapter 19: Debugging with GDB Chapter 20: Profiling and Tracing Chapter 21: Real-Time Programming Other Books You May Enjoy

A better way of managing device nodes

Creating device nodes statically with mknod is quite hard work and inflexible. There are other ways to create device nodes automatically on demand:

  • devtmpfs: This is a pseudo filesystem that you mount over /dev at boot time.
    The kernel populates it with device nodes for all the devices that the kernel currently knows about, and it creates nodes for new devices as they are detected at runtime. The nodes are owned by root and have default permissions of 0600. Some well-known device nodes, such as /dev/null and /dev/random, override the default to 0666. To see exactly how this is done, take a look at the Linux source file drivers/char/mem.c and see how struct memdev is initialized.
  • mdev: This is a BusyBox applet that is used to populate a directory with device nodes and to create new nodes as needed. There is a configuration file, /etc/mdev.conf, which contains rules for ownership and the mode of the nodes.
  • udev: This is the mainstream...
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