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)

Communicating with a pipe

In this recipe, we'll create a program that forks and then communicates between two processes using a pipe. Sometimes, when we fork a process, the parent and the child need a way to communicate. A pipe is often a simple way to do just that.

Knowing how to communicate and interchange data between a parent and a child process is important when you're writing more complex programs.

Getting ready

For this recipe, we'll only need the GCC compiler, the Make tool, and the generic Makefile.

How to do it…

Let's write a simple program that forks:

  1. Write the following code in a file and name it pipe-example.c. We'll go through the code step by step. Remember that all the code goes in the same file.

We'll start with the include lines and the main() function. Then, we'll create an integer array of size 2. The pipe will use that array later. The first integer in the array (0) is the file descriptor for...