Rilegato

ISBN 10: 0321219147 ISBN 13: 9780321219145

Casa editrice: Addison-Wesley Professional, 2004

"The first edition of this book has always been kept within arm's reach of my desk due to the wonderful explanations of all areas of the Linux userspace API. This second edition greatly overshadows the first one, and will replace it."
--Greg Kroah-Hartman, Linux kernel programmer

Develop Software that Leverages the Full Power of Today's Linux

Linux Application Development, Second Edition, is the definitive reference for Linux programmers at all levels of experience, including C programmers moving from other operating systems. Building on their widely praised first edition, leading Linux programmers Michael Johnson and Erik Troan systematically present the key APIs and techniques you need to create robust, secure, efficient software or to port existing code to Linux.

This book has been fully updated for the Linux 2.6 kernel, GNU C library version 2.3, the latest POSIX standards, and the Single Unix Specification, Issue 6. Its deep coverage of Linux-specific extensions and features helps you take advantage of the full power of contemporary Linux. Along the way, the authors share insights, tips, and tricks for developers working with any recent Linux distribution, and virtually any version of Unix.

Topics include

• Developing in Linux: understanding the operating system, licensing,
• and documentation
• The development environment: compilers, linker and loader, and unique
• debugging tools
• System programming: process models, file handling, signal processing, directory operations, and job control
• Terminals, sockets, timers, virtual consoles, and the Linux console
• Development libraries: string matching, terminal handling, command-line parsing, authentication, and more
• Hundreds of downloadable code samples

New to this edition

• The GNU C library (glibc), underlying standards, and test macros
• Writing secure Linux programs, system daemons, and utilities
• Significantly expanded coverage of memory debugging, including Valgrind and mpr
• Greatly improved coverage of regular expressions
• IPv6 networking coverage, including new system library interfaces for using IPv6 and IPv4 interchangeably
• Coverage of strace, ltrace, real-time signals, poll and epoll system calls, popt library improvements, Pluggable Authentication Modules (PAM), qdbm, and much more
• Improved index and glossary, plus line-numbered code examples

About the Author:

Michael K. Johnson is an operating system engineer at Specifix. He was formerly an operating system developer for Red Hat, where he managed the kernel team for three and a half years, and was founding technical leader of the Fedora Project. He occasionally teaches full-day tutorials on Linux application development.

Erik W. Troan, cofounder and Executive VP of Operating Systems at Specifix, was formerly Vice President of Product Engineering at Red Hat, where he was responsible for specifying and building technologies such as RPM, Linux operating systems, the Red Hat Network, high-performance Web servers, and the infrastructure for Red Hat's Web site.

Excerpt. © Reprinted by permission. All rights reserved.:

We wrote this book for experienced (or not-so-experienced, but eager-to-learn) programmers who want to develop Linux software or to port software from other platforms to Linux. This is the book we wish we had when we were learning to program for Linux, and the book we now keep on our desks for reference. As soon as we wrote the first three chapters of the first edition, we were using the drafts as reference material while we worked.

This second edition removes outdated information, adds new information, and introduces an online version. You can now browse and search the entire content of this book at http://ladweb.net/ to make this book even more useful to you.

Linux is designed to be similar to Unix. This book gives you a good background in Unix programming basics and style. Linux is not fundamentally different from Unix; it differs in some details, but no more than one Unix version typically differs from another Unix version. This book is very much a Unix programming guide that is written from a Linux viewpoint and with specific Linux information.

Linux also has unique extensions, such as its direct screen access capabilities (see Chapter 21), and it has features that are used more often on it than on other systems, such as the popt library (see Chapter 26). This book covers many of those extensions and features so that you can write programs that truly take advantage of Linux.

• If you are a C programmer, but you know neither Unix nor Linux, reading this book cover-to-cover and working with the examples should put you well on the road to being a competent Linux programmer. With the aid of system-specific documentation, you should find the transition to any version of Unix easy.
• If you are already a proficient Unix programmer, you will find that this book makes your transition to Linux easier. We have tried very hard to make it easy for you to find precisely the information you need to know. We also carefully and clearly cover topics that sometimes trip up even experienced Unix programmers, such as process and session groups, job control, and tty handling.
• If you are already a Linux programmer, this book covers confusing topics clearly and will make many of your programming tasks easier. Nearly every chapter will stand alone for you, because you already possess the essential knowledge of Linux on which they are based. No matter how experienced you are, you will find material here that you will appreciate having at your elbow.

This book is different from typical Unix programming texts because it is unabashedly specific to a particular operating system. We do not try to cover all the differences between different Unix-like systems; to do so would not be useful to Linux programmers, Unix programmers, or C programmers unfamiliar with Linux or Unix. We know from our own experience that once you learn how to program well for any Unix-like system, the others are easy to learn.

This book does not cover all the details of Linux programming. It does not explain the basic interface specified by ANSI/ISO C---other books do that quite well. It does not cover the wealth of other programming languages available for Linux, and it does not cover the graphical programming libraries that are identical no matter what system you are using. Instead, we point you to books that specialize in those areas. Without extraordinary verbosity, we cover the information you need to know to go from being a C programmer for another system, such as Windows, Macintosh, or even DOS, to being a C programmer for Linux.

Linux Application Development is written in four parts:

• The first part introduces you to Linux---the operating system, license terms, and online system documentation.
• The second part covers the most important facets of the development environment---the compilers, linker and loader, and some debugging tools that are not widely used on other platforms.
• The third part is the heart of the book---it describes the interface to the kernel and to system libraries that are meant primarily as an interface to the kernel. In this section, only Chapters 19, 20, and 21 are very Linux-specific; most of this section covers general Unix programming from a Linux perspective. A new chapter in this second edition, Chapter 22, covers the basics of writing secure programs.
• The fourth part rounds out your knowledge---it includes descriptions of some important libraries that provide interfaces that are more independent of the kernel. These libraries are, properly speaking, not Linux-specific, but several are used more often on Linux systems than on other systems.

If you are already familiar with Linux or Unix programming, you will be able to read the chapters in this book in any order, skipping any that do not interest you. If you are not familiar with either Linux or Unix, most of the chapters will stand alone, but you will probably want to read Chapters 1, 2, 4, 5, 9, 10, 11, and 14 first, as they give you most of what you need to know to read the other chapters. In particular, Chapters 10, 11, and 14 form the core of the Unix and Linux programming model.

The following books, although they may overlap a little here and there, mostly complement this book by being simpler, more advanced, or on related topics.

• The C Programming Language, second edition concisely teaches ANSI standard C programming, with scant reference to the operating system. It recommends that readers have either some programming knowledge or "access to a more knowledgeable colleague."
• Practical C Programming teaches C programming and style in a step-by-step, easy-to-follow manner that is designed for people with no prior programming experience.
• Programming with GNU Software is an introduction to the GNU programming environment, including chapters on running the C compiler, the debugger, the make utility, and the RCS source code control system.
• Advanced Programming in the UNIX Environment covers most important Unix and Unix-like systems, although it predates Linux. It covers similar material to the final two parts of Linux Application Development: system calls and shared libraries. It also provides many examples and explains the difference between various Unix versions.
• UNIX Network Programming thoroughly covers network programming, including legacy types of networking that are not available on Linux, at least as we write this. While reading this book, stick to the Berkeley socket interface (see Chapter 17) to maintain maximum portability. This book may be useful if you need to make a few slight changes to port your Linux network program to some brand of Unix.
• A Practical Guide to Red Hat Linux 8 is a 1,500-page tome that contains introductions to using Linux, shell programming, and system administration. While this book does mention Red Hat Linux 8, most of the information it contains applies to all flavors of Linux. It also contains a summary reference to many of the utilities that are included with a Linux system.
• Linux in a Nutshell is smaller and shorter and concentrates on a summary utility reference derived from O'Reilly's earlier nutshell references.
• Linux Device Drivers, second edition teaches those who have never touched operating system code, as well as those who have, how to write Linux device drivers.

See the bibliography for an extensive list of related titles.

All the source code in this book comes from working examples that we have tested while writing. All of the source code in this book is available in electronic format at http://ladweb.net/ In the interest of clarity, some short source code segmentscheck only for likely errors that document how the system works rather than check for all possible errors. However, in the full programs in the book and on our Web site, we have made an attempt (we are not perfect) to check for all reasonable errors.

This book will teach you which functions to use and how they fit together; we encourage you to learn also how to use the reference documentation, the great majority of which was included with your system. Chpater 3 discusses how to find online information on your Linux system.

Linux is a rapidly developing operating system, and by the time you read this book, some facts (although we hope little substance) will no doubt have changed. We wrote this book in reference to the Linux 2.6 kernel and the GNU C library version 2.3.

With your help, we will maintain a list of errata and changes on the World Wide Web at http://ladweb.net/errata.html

We welcome your comments sent to lad-comments@ladweb.net. We will read your comments, although we cannot promise to respond to them individually.

Second Edition

Additions to and modifications from the first to the second edition include:

• The whole book has been updated to take into account the new Single Unix Specification, issue 6; the updated version of the POSIX standard.
• A table of example source code has been added to make it easier to find sample programs.
• Small segments of example source code now are listed with line numbers printed, making it easier for you to orient yourself in respect to each entire soure code example.
• Chapter 1 has an updated and expanded history of Linux development.
• Chapter 4 now discusses the strace and ltrace utilities.
• Chapter 6 is a new chapter that discusses the GNU C library (glibc) and the standards on which it is based. Of particular interest, it explains how (and why) to use feature test macros. It also describes some basic types used by system calls discussed throughout the book, how to discover the capabilities of your system at run time, covers some miscellaneous sy...