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)

Controlling and terminating processes using signals

Now that we know a bit more about processes, it's time to move on to signals and learn how we can kill and control a process using signals. In this recipe, we will also write our first C program, which will have a signal handler.

Getting ready

For this recipe, you'll only need what's listed in the Technical requirements section of this chapter.

How to do it…

In this recipe, we'll explore how to control and terminate processes with signals. Let's get started:

  1. Let's start by listing the signals we can send to a process using the kill command. The list you get from this command is rather long, so it's not been included here. The most interesting—and used—signals are the first 31:
    $> kill -L
  2. Let's see how some of these signals work. We can send the STOP signal (number 19) to a process, which has the same effect as we saw when hitting Ctrl+Z in sleep...