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)

Finding a simple memory leak with Valgrind

Valgrind is a neat program for finding memory leaks and other memory-related bugs. It can even tell you if you put too much data inside an allocated memory area. These can all be hard bugs to find without a tool like Valgrind. Even if a program leaks memory or puts too much data in a memory area, it can still run fine for a long time. That's what makes those bugs so hard to find. But with Valgrind, we can check the program for all sorts of memory-related problems.

Getting started

For this recipe, you'll need the Valgrind tool installed on your computer. If you haven't already installed it, you can follow the instructions listed in the Technical requirements section of this chapter.

You'll also need the Make tool, the GCC compiler, and the Makefile from the Starting GDB recipe.

How to do it…

In this recipe, we'll write a program that allocates memory using calloc() but never frees it with free...