C Programming for System, Network, and Cloud Engineers: Techniques for Processes, Memory, Network Applications, and Linux Namespaces

Table of Contents....5

About the Author....13

About the Technical Reviewer....14

Acknowledgments....15

Introduction....16

Chapter 1: Basic Computer System Architecture and Essential Operating System Concepts....18

Basic Computer System Architecture....19

CPU Architecture....20

Memory Hierarchy....22

CPU and IO Device Interactions....23

Inspect System Configurations on a Linux OS....24

Operating System Responsibilities....28

Users Program Access to OS Services....30

OS Process Management Activities and Services....33

OS Role in Processes Management....34

OS Offering Services for User Programs....37

OS Role in Memory Management....38

OS IO Devices, File Management, and Protection Services....39

Importance of Compiler, Linker, and Loader....40

Compiler....41

Compiler Options for Application Performance Tuning....42

Compiler Options to Protect Application Code....43

Compiler Options to Handle Runtime Errors....45

Linking and Loading Options....46

Developers Must Know Linking Options to Handle Runtime Errors....47

Runtime Environment of a Process....48

Process Memory Layout....48

Process Execution Environment....51

Process and Memory Access-Related Issues....52

Process and IO Devices Access-Related Issues....55

Process Reliability and Security Issues....57

Process Memory Layout-Related Access Checkpoints....58

Careful About Shared Libraries Access....60

Interprocess Communication-Related Access Checkpoints....60

C Programmer Powers and Responsibilities....61

C Programming Powers....62

C Programmer Responsibilities....64

Summary....67

Chapter 2: Quick Revision of Powerful C Constructs....68

Procedure-Oriented Programming....69

Understand C Functions Memory Layout and Execution Procedure....73

Recursive Functions....88

Nested Functions in GNU C....94

Arrays....98

Powerful Ways for Organizing Arrays Data Elements and Accessing....101

Arrays: Indexing Ways for Accessing Data Structures....103

Hands-On Activities for Organizing Arrays Data Elements and Accessing Them Efficiently....108

Strings and Buffers....117

Strings Processing Hands-On Activities....122

C Structures....129

Passing Structure Variables Between Functions....132

Structure and Its Data Members Memory Layout....134

Hands-On Activity-1....135

Power of C Structures for Modeling....140

Data Structures Modeling....140

Protocols and Protocol Stack Modeling....143

Hands-On Activity-2....145

C Unions....149

An Important Use Case of Unions....151

Hands-On Activity....152

Summary....157

Practice Tasks....158

Chapter 3: Practice C Programming with Important Tools....160

Compilation and Linking Techniques for Enhancing Programming Skills....161

gcc Compilation Options for Performance Tuning....162

gcc Compilation Options for Linking....168

gcc Compilation Options for Secured Code....178

Memory Access Errors Handling Techniques and Tools....189

Memory and Other Important Errors Handling gcc Options for Reliable Code....189

Memory Error Handling Using Valgrind....198

Code Coverage Analysis for Avoiding Performance Issues....200

Code Coverage Tools (gcc and gcov) Usage Steps....202

Hands-On Activity....205

GDB: The GNU Project Debugger....212

Go Through a Code Execution and Inspect the Code and Data....212

Inspect the Code and Data Using gdb Commands....219

Handle Application Runtime Errors....226

Summary....236

Practice Tasks....237

Chapter 4: Power of C: Pointers....239

Importance of Pointer Programming....240

Basic Concepts of C Pointers....241

Basic Pointers....241

Multilevel Pointers....242

Use Cases of C Pointers....244

Efficient Communication Approach for Functions....245

Flexible Data Accessing Approaches....247

Pointers to Data Structures....248

Pointers to Arrays....248

Pointers to Structures....249

Pointers Flexible Traversals....250

Void Pointers to Implement Generic Data Structures....251

Efficient and Reliable Ways to Access Arrays and Strings Using Pointers....252

Pointers to Array Subparts....253

Pointers to Multidimensional Arrays....254

Pointers to Strings....255

Pointers to Simple Strings....256

Pointers to Array of Strings....256

Pointers to Array of Array of Strings....257

Hands-On Activities for Organizing Arrays Data Elements and Accessing Them Efficiently....258

Efficient and Reliable Ways to Access Structures Using Pointers....262

Basic Pointers Accessing Ways for Structures....263

Efficient Ways for Structure Variables Passing to Functions....263

Advanced Pointers Accessing Ways for Structures....265

Hands-On Activity....266

Pointers and Functions for Powerful Programming Techniques....271

Pointers to a Variety of Functions....272

Basic Function Pointers....272

Advanced Function Pointers....273

Typedef....274

Declare Array of Function Pointers....274

Declare a Pointer to a Function Returning an Array of Function Pointers....275

C Ways for Polymorphism....277

A Quick Example....277

Use typedef to Simplify Interface Name....278

Hands-On Activity....278

Summary....283

Practice Tasks....283

Chapter 5: C Programming for Memory Management....285

Introduction to Dynamic Memory Management....286

Importance of Dynamic Memory Management....286

Important C System Calls for Memory Management....287

Important C System Calls for Memory Management....290

C Library Functions for Basic Dynamic Memory Management....290

C System Calls for Extending Memory Blocks Dynamically....293

C System Calls for Handling Multiple Blocks of Memory Allocation....295

Error Handling Programming Techniques for Memory Management....297

Best Dynamic Memory Management Practices....297

Memory Error Handling Techniques Using Valgrind....301

Hands-On Activity Using Valgrind Tools....304

Setting Up Memory Buffers and Accessing Them in a Reliable Manner....309

Hands-On Activity-1....310

Hands-On Activity-2....316

Hands-On Activity-3....322

Summary....328

Practice Tasks....328

Chapter 6: Process and Thread Management Tasks for C Programmers....330

Introduction to Processes and Threads....331

Process Management Basic Activities Using Fork....332

Thread Management Basic Activities....334

Explore the Power of Process Management Using C Programming....339

Developers Role and Activities in Process Management....339

Creating a Specific Number of Processes....342

Control the Multiple Processes Execution Order....346

Create N Processes and Load Them with Executable Images....350

Safe and Reliable Programming Ways for Process Management....355

Importance of Parent and Child Processes Exit Order....357

Orphan Process....357

Zombie Process....359

Handle Carefully Data Sharing Activities Between Parent and Child Processes....360

Parent and Child Processes Segments....361

Use Valgrind to Check Processes for Memory Leaks....364

Sharing of File Descriptors Between Parent and Child Processes....365

Use Valgrind to Check File Descriptor Leaks....367

Reliable Ways of Executing a New Process in a Child Process....369

Importance of Interrupt Handling in Process Management....372

Explore Power of Threads Management Using C Programming....378

Developers Role in Threads Management....378

Creating Threads and Assigning Tasks....378

Challenges in Assigning Specific Tasks and Data to Threads....382

Common Threads Issues and Respective Solutions....385

Critical Section and Synchronization Issues Handling Tasks....385

Pthreads Mutex Objects for Locking and Synchronization....386

Mutex and Conditional Variable for Synchronization....388

Common Data Sharing Issues and Threads Performance....391

False Sharing....391

Hands-On Activity-1....393

Hands-On Activity-2....398

Safe and Reliable Programming Ways for Threads Management....402

Improve the Performance of a Multithreaded Application....402

Multithreading Application Performance Tuning....403

First Approach....406

Second Approach....407

Third Approach....409

Quickly Identify and Handle Threads Synchronization Issues....411

Identify Data Race Conditions Quickly....411

Identify Locking Issues Quickly....413

Summary....416

Practice Tasks....417

Chapter 7: Handle Interprocess Activities Using C Programming....419

Essential Linux Interprocess Communication (IPC) Approaches....420

Linux Basic Services for File Handling....421

Importance of dup and dup2....422

PIPEs....423

OS Role in Pipes Management....423

Use Case of PIPEs....424

FIFO....424

OS Role in FIFO Management....425

Use Case of FIFOs....426

Message Queues....426

OS Role in Message Queues Management....427

Use Case of Message Queues....428

Shared Memory....428

OS Role in Shared Memory Management....429

Use Case of Shared Memory....429

Semaphores....430

OS Role in Semaphores Management....430

Use Case of Semaphores....431

Explore C Programming and Linux IPC Tools for IPC Management....432

Usage of PIPEs in C....432

Sample C Program Using a Pipe....433

Developers Role in Case of Pipe Usage....435

Usage of FIFO in C....436

Sample C Program Using a FIFO....437

Developers Role in Case of FIFO Usage....440

Usage of Message Queues in C....441

Sample C Program Using a Message Queue....443

Developers Role in Case of Message Queue Usage....447

Usage of Shared Memory in C....448

Sample C Program Using a Shared Memory....449

Developers Role in Case of Shared Memory Usage....453

Explore C Ways to Implement Service Chaining and Asynchronous Programming....454

Hands-On Activity-1....455

Hands-On Activity-2....459

Hands-On Activity-3....465

Essential IPC Synchronization Handling Tools....471

Semaphores....472

Usage of Semaphore in C....473

Developers Role in Case of Shared Memory Usage....474

Hands-On Activity-1....475

Hands-On Activity-2....480

Summary....485

Practice Tasks....486

Chapter 8: Essential Network Socket Programming Skills....487

Quick Introduction to TCPIP Stack and Network Applications....488

TCPIP Stack....489

TCPIP Layers....489

TCPIP Stack and Network Interactions....491

Network Devices and Their TCPIP Stack Layers....492

Basics of Protocol Address....492

IP Address....493

TCP Socket Programming....495

TCP Rules....496

TCP Connection Setup....496

TCP Connection Shutdown....497

TCP Socket Programming Constructs....500

General TCP Server Program Structure....510

Multiprocess TCP Server Program Structure....512

General TCP Client Program Structure....514

TCP Socket Programming Practice....515

TCP Server Program for Waiting for Messages....516

TCP Client Program for Messages Exchange....520

Multiprocess TCP Server Program....524

UDP Socket Programming....529

UDP Socket Programming in C....531

Importance of Connection-Oriented Socket for UDP Clients....532

UDP Traffic Exchange System Calls....533

UDP Socket Programming in C....537

General UDP Server Program Structure....537

General UDP Connection-Less Client Program Structure....539

General UDP Connection-Oriented Client Program Structure....541

Hands-On Activity-1....543

C Programming Ways for Monitoring and Inspecting TCPUDP Applications Traffic....553

Packet Monitoring and Filtering Activities....553

Basic Traffic Monitoring and Inspecting Program Structure....554

Hands-On Activity-1....556

Hands-On Activity-2....561

Summary....565

Practice Tasks....565

Chapter 9: Essential Advanced Socket Programming Ways Using C Sockets....567

Important Socket Programming Approaches....568

Multiprocessing and Multithreading....570

Must-Know Socket Options....573

Non-blocking Socket Programming....578

Non-blocking Ways of Socket Programming....579

Usage of fcntl and select....579

Hands-On Activity-1....582

Hands-On Activity-2....592

Handle TCP Client-Server Performance and Reliability Issues....598

The Reliable TCP Server and Client....601

Hands-On Activity-1....611

Hands-On Activity-2....613

Hands-On Activity-3....616

Handle UDP Client-Server Performance and Reliability Issues....618

Hands-On Activity-1....619

Hands-On Activity-2....626

Summary....635

Practice Tasks....636

Chapter 10: Learn C Programming Skills for Virtualization....637

Introduction to Linux Namespaces....638

Linux Namespaces....639

Linux cgroups....641

Learn How to Program Linux Namespaces and cgroups....644

Detach a Process from Inherited Namespaces....644

Unshare System Call Usage....645

Detach from the UTS Namespace Using unshare....646

Detach from the User Namespace Using unshare....648

Detach from the Network Namespace Using unshare....649

Attach a Process with Existing Namespaces....650

Set Up a New Namespace Using unshare and Attach It with setns....651

Attach with an Existing UTS Namespace Using setns....652

Attach with Existing User and Network Namespaces....654

Clone New Processes with Suitable Namespaces....657

Start Multiple Processes with Necessary New Namespaces....659

Start a Process with Multiple Namespaces....662

Start a Process with Limited Namespaces and Attach New Namespaces Later....663

Learn Setting Up and Using Control Groups....666

Setting Up a Suitable Resource Control Group....667

Configure Resource Control Group Limits....667

Assign Processes to a cgroup....668

Experiment with Process and Memory Namespaces....669

Hands-On Activity-1....670

Hands-On Activity-2....675

Hands-On Activity-3....680

Hands-On Activity-4....685

Hands-On Activity-5....688

Experiment with Networking Namespaces....693

Learn Setting Up Network Namespaces....693

Practice Using iproute2....694

Various Virtual Networks Setups....696

Basic Virtual Network Setup....696

Interconnect Network Namespace and Host....698

Interconnect Two Different Subnet Network Namespaces....699

Hands-On Activity-1....702

Hands-On Activity-2....705

Hands-On Activity-3....708

Summary....713

Master essential C programming skills to develop efficient and reliable system software and applications. Whether you are a system, network, or cloud engineer―this comprehensive guide is designed to help you tackle complex C programming challenges.

Throughout this book, you will start by learning basic computer system architecture and essential operating systems concepts to implement reliable and efficient C code. You will then progress through essential C programming skills, including arrays, strings, unions, pointers, and memory management, while practicing runtime error handling and best practices. Next, you will be ready for more advanced topics, like system and network programming, before concluding with a deep dive into Linux namespaces and their role in virtualization in cloud environments.

With an emphasis on real-world applications and best practices, this book allows you to experiment with the foundational and advanced constructs for important use cases.

What You Will Learn:

• Implement reliable C programming techniques for handing arrays, struct, pointers, and memory.
• Inspect and manage C processes and threads in a runtime environment.
• Learn essential C socket programming skills, error handing, and usage of socket options to handle network applications reliability.
• Master fundamentals of virtualization concepts using C programming and Linux namespaces.

Who This Book is for:

Beginner System, Network and Cloud Engineers, though intermediate and advanced users will also benefit from mastering essential skill sand exploring advanced coverage.