Book Image

Mastering Embedded Linux Programming

By : Chris Simmonds
Book Image

Mastering Embedded Linux Programming

By: Chris Simmonds

Overview of this book

Mastering Embedded Linux Programming takes you through the product cycle and gives you an in-depth description of the components and options that are available at each stage. You will begin by learning about toolchains, bootloaders, the Linux kernel, and how to configure a root filesystem to create a basic working device. You will then learn how to use the two most commonly used build systems, Buildroot and Yocto, to speed up and simplify the development process. Building on this solid base, the next section considers how to make best use of raw NAND/NOR flash memory and managed flash eMMC chips, including mechanisms for increasing the lifetime of the devices and to perform reliable in-field updates. Next, you need to consider what techniques are best suited to writing applications for your device. We will then see how functions are split between processes and the usage of POSIX threads, which have a big impact on the responsiveness and performance of the final device The closing sections look at the techniques available to developers for profiling and tracing applications and kernel code using perf and ftrace.
Table of Contents (22 chapters)
Mastering Embedded Linux Programming
About the Author
About the Reviewers

Updating in the field

There have been several well-publicized security flaws, including Heartbleed (a bug in the OpenSSL libraries) and Shellshock (a bug in the bash shell), both of which could have serious consequences for embedded Linux devices that are currently deployed. For this reason alone, it is highly desirable to have a mechanism to update devices in the field so that you can fix security problems as they arise. There are other good reasons as well: to deploy other bug fixes and feature updates.

The guiding principle of update mechanisms is that they should do no harm, remembering Murphy's Law: if it can go wrong, it will go wrong, eventually. Any update mechanism must be:

  • Robust: It must not render the device inoperable. I will talk about updates being atomic; either the system is updated successfully or not updated at all and continues to run as before.

  • Failsafe: It must handle interrupted updates gracefully.

  • Secure: It must not allow unauthorized updates, otherwise it will become...