Book Image

Linux System Programming Techniques

By : Jack-Benny Persson
Book Image

Linux System Programming Techniques

By: Jack-Benny Persson

Overview of this book

Linux is the world's most popular open source operating system (OS). Linux System Programming Techniques will enable you to extend the Linux OS with your own system programs and communicate with other programs on the system. The book begins by exploring the Linux filesystem, its basic commands, built-in manual pages, the GNU compiler collection (GCC), and Linux system calls. You'll then discover how to handle errors in your programs and will learn to catch errors and print relevant information about them. The book takes you through multiple recipes on how to read and write files on the system, using both streams and file descriptors. As you advance, you'll delve into forking, creating zombie processes, and daemons, along with recipes on how to handle daemons using systemd. After this, you'll find out how to create shared libraries and start exploring different types of interprocess communication (IPC). In the later chapters, recipes on how to write programs using POSIX threads and how to debug your programs using the GNU debugger (GDB) and Valgrind will also be covered. By the end of this Linux book, you will be able to develop your own system programs for Linux, including daemons, tools, clients, and filters.
Table of Contents (14 chapters)

Chapter 7: Using systemd to Handle Your Daemons

Now that we know how to build our own daemons, it's time to see how we can get Linux to handle them using systemd. In this chapter, we will learn what systemd is, how to start and stop services, what unit files are, and how to create them. We will also learn how daemons are logged to systemd and how we read those logs.

We will then learn about different kinds of services and daemons that systemd can handle and put the daemon from the previous chapter under systemd control.

In this chapter, we'll cover the following recipes:

  • Getting to know systemd
  • Writing a unit file for a daemon
  • Enabling and disabling a service—and starting and stopping it
  • Creating a more modern daemon for systemd
  • Making the new daemon a systemd service
  • Reading the journal