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)

Setting access rights and ownership

In the previous recipe, we learned how to read the access rights of files and folders. In this recipe, we'll learn how to set access rights, using both the chmod command and the chmod() system call. We will also learn how to change the owner and group of a file, using both the chown command and the chown() system call.

Knowing how to set access rights properly will help you keep your systems and files secure.

Getting ready

For this recipe, you'll only need what's listed in the Technical requirements section of this chapter. It's also a good idea to read the previous recipe to understand permissions in Linux. You will also need the my-stat-v2 program from the previous recipe.

How to do it…

These steps will teach us how to change the access rights and ownership of files and directories.

Access rights

We will start by setting the access rights of a file by using the chmod command. We will then write a...