Linux程序设计 英文版PDF电子书下载

PART Ⅰ Files and Users 1

Chapter 1 Introduction 3

1.1 The Linux/Unix File Model 4

1.1.1 Files and Permissions 4

1.1.2 Directories and Filenames 6

1.1.3 Executable Files 7

1.1.4 Devices 9

1.2 The Linux/Unix Process Model 10

1.2.1 Pipes：Hooking Processes Together 12

1.3 Standard C vs.Original C 12

1.4 Why GNU Programs Are Better 14

1.4.1 Program Design 15

1.4.2 Program Behavior 16

1.4.3 C Code Programming 16

1.4.4 Things That Make a GNU Program Better 17

1.4.5 Parting Thoughts about the"GNU Coding Standards" 19

1.5 Portability Revisited 19

1.6 Suggested Reading 20

1.7 Summary 21

Exercises 22

Chapter 2 Arguments,Options,and the Environment 23

2.1 Option and Argument Conventions 24

2.1.1 POSIX Conventions 25

2.1.2 GNU Long Options 27

2.2 Basic Command-Line Processing 28

2.2.1 The V7 echo Program 29

2.3 Option Parsing：getopt()and getopt_long() 30

2.3.1 Single-Letter Options 30

2.3.2 GNU getopt()and Option Ordering 33

2.3.3 Long Options 34

2.3.3.1 Long Options Table 34

2.3.3.2 Long Options,POSIX Style 37

2.3.3.3 getopt_long()Return Value Summary 37

2.3.3.4 GNU getopt()or getopt_long()in User Programs 39

2.4 The Environment 40

2.4.1 Environment Management Functions 41

2.4.2 The Entire Environment：environ 43

2.4.3 GNU env 44

2.5 Summary 49

Exercises 50

Chapter 3 User-Level Memory Management 51

3.1 Linux/Unix Address Space 52

3.2 Memory Allocation 56

3.2.1 Library Calls：malloc(),calloc(),realloc(),free() 56

3.2.1.1 Examining C Language Details 57

3.2.1.2 Initially Allocating Memory：malloc() 58

3.2.1.3 Releasing Memory：free() 60

3.2.1.4 Changing Size：realloc() 62

3.2.1.5 Allocating and Zero-filling：calloc() 65

3.2.1.6 Summarizing from the GNU Coding Standards 66

3.2.1.7 Using Private Allocators 67

3.2.1.8 Example：Reading Arbitrarily Long Lines 67

3.2.1.9 GLIBC Only：Reading Entire Lines：getline()and getdelim() 73

3.2.2 String Copying：strdup() 74

3.2.3 System Calls：brk()and sbrk() 75

3.2.4 Lazy Programmer Calls：alloca() 76

3.2.5 Address Space Examination 78

3.3 Summary 80

Exercises 81

Chapter 4 Files and File I/O 83

4.1 Introducing the Linux/Unix I/O Model 84

4.2 Presenting a Basic Program Structure 84

4.3 Determining What Went Wrong 86

4.3.1 Values for errno 87

4.3.2 Error Message Style 90

4.4 Doing Input and Output 91

4.4.1 Understanding File Descriptors 92

4.4.2 Opening and Closing Files 93

4.4.2.1 Mapping FILE Variables to File Descriptors 95

4.4.2.2 Closing All Open Files 96

4.4.3 Reading and Writing 96

4.4.4 Example：Unix cat 99

4.5 Random Access：Moving Around within a File 102

4.6 Creating Files 106

4.6.1 Specifying Initial File Permissions 106

4.6.2 Creating Files with creat() 109

4.6.3 Revisiting open() 110

4.7 Forcing Data to Disk 113

4.8 Setting File Length 114

4.9 Summary 115

Exercises 115

Chapter 5 Directories and File Metadata 117

5.1 Considering Directory Contents 118

5.1.1 Definitions 118

5.1.2 Directory Contents 120

5.1.3 Hard Links 122

5.1.3.1 The GNU link Program 123

5.1.3.2 Dot and Dot-Dot 125

5.1.4 File Renaming 125

5.1.5 File Removal 126

5.1.5.1 Removing Open Files 127

5.1.5.2 Using ISO C：remove() 127

5.1.6 Symbolic Links 128

5.2 Creating and Removing Directories 130

5.3 Reading Directories 132

5.3.1 Basic Directory Reading 133

5.3.1.1 Portability Considerations 136

5.3.1.2 Linux and BSD Directory Entries 137

5.3.2 BSD Directory Positioning Functions 138

5.4 Obtaining Information about Files 139

5.4.1 Linux File Types 139

5.4.2 Retrieving File Information 141

5.4.3 Linux Only：Specifying Higher-Precision File Times 143

5.4.4 Determining File Type 144

5.4.4.1 Device Information 147

5.4.4.2 The V7 cat Revisited 150

5.4.5 Working with Symbolic Links 151

5.5 Changing Ownership,Permission,and Modification Times 155

5.5.1 Changing File Ownership：chown(),fchown(),and lchown() 155

5.5.2 Changing Permissions：chmod()and fchmod() 156

5.5.3 Changing Timestamps：utime() 157

5.5.3.1 Faking utime(file,NULL) 159

5.5.4 Using fchown()and fchmod()for Security 161

5.6 Summary 162

Exercises 163

Chapter 6 General Library Interfaces—Part 1 165

6.1 Times and Dates 166

6.1.1 Retrieving the Current Time：time()and difftime() 167

6.1.2 Breaking Down Times：gmtime()and localtime() 168

6.1.3 Formatting Dates and Times 170

6.1.3.1 Simple Time Formatting：asctime()and ctime() 170

6.1.3.2 Complex Time Formatting：strftime() 171

6.1.4 Converting a Broken-Down Time to a time_t 176

6.1.5 Getting Time-Zone Information 178

6.1.5.1 BSD Systems Gotcha：timezone(),Not timezone 179

6.2 Sorting and Searching Functions 181

6.2.1 Sorting：qsort() 181

6.2.1.1 Example：Sorting Employees 183

6.2.1.2 Example：Sorting Directory Contents 188

6.2.2 Binary Searching：bsearch() 191

6.3 User and Group Names 195

6.3.1 User Database 196

6.3.2 Group Database 199

6.4 Terminals：isatty() 202

6.5 Suggested Reading 203

6.6 Summary 203

Exercises 205

Chapter 7 Putting It All Together：ls 207

7.1 V7 ls Options 208

7.2 V7 ls Code 209

7.3 Summary 225

Exercises 226

Chapter 8 Filesystems and Directory Walks 227

8.1 Mounting and Unmounting Filesystems 228

8.1.1 Reviewing the Background 228

8.1.2 Looking at Different Filesystem Types 232

8.1.3 Mounting Filesystems：mount 236

8.1.4 Unmounting Filesystems：umount 237

8.2 Files for Filesystem Administration 238

8.2.1 Using Mount Options 239

8.2.2 Working with Mounted Filesystems：getmntent() 241

8.3 Retrieving Per-Filesystem Information 244

8.3.1 POSIX Style：statvfs()and fstatvfs() 244

8.3.2 Linux Style：statfs()and fstatfs() 252

8.4 Moving Around in the File Hierarchy 256

8.4.1 Changing Directory：chdir()and fchdir() 256

8.4.2 Getting the Current Directory：getcwd() 258

8.4.3 Walking a Hierarchy：nftw() 260

8.4.3.1 The nftw()Interface 261

8.4.3.2 The nftw()Callback Function 263

8.5 Walking a File Tree：GNU du 269

8.6 Changing the Root Directory：chroot() 276

8.7 Summary 277

Exercises 278

PART Ⅱ Processes,IPC,and Internationalization 281

Chapter 9 Process Management and Pipes 283

9.1 Process Creation and Management 284

9.1.1 Creating a Process：fork() 284

9.1.1.1 After the fork()：Shared and Distinct Attributes 285

9.1.1.2 File Descriptor Sharing 286

9.1.1.3 File Descriptor Sharing and close() 288

9.1.2 Identifying a Process：getpid()and getppid() 289

9.1.3 Setting Process Priority：nice() 291

9.1.3.1 POSIX vs.Reality 293

9.1.4 Starting New Programs：The exec()Family 293

9.1.4.1 The execve()System Call 294

9.1.4.2 Wrapper Functions：execl()et al 295

9.1.4.3 Program Names and argv[0] 297

9.1.4.4 Attributes Inherited across exec() 298

9.1.5 Terminating a Process 300

9.1.5.1 Defining Process Exit Status 300

9.1.5.2 Returning from main() 301

9.1.5.3 Exiting Functions 302

9.1.6 Recovering a Child's Exit Status 305

9.1.6.1 Using POSOX Functions：wait()and waitpid() 306

9.1.6.2 Using BSD Functions：wait3()and wait4() 310

9.2 Process Groups 312

9.2.1 Job Control Overview 312

9.2.2 Process Group Identification：getpgrp()and getpgid() 314

9.2.3 Process Group Setting：setpgid()and setpgrp() 314

9.3 Basic Interprocess Communication：Pipes and FIFOs 315

9.3.1 Pipes 315

9.3.1.1 Creating Pipes 316

9.3.1.2 Pipe Buffering 318

9.3.2 FIFOs 319

9.4 File Descriptor Management 320

9.4.1 Duplicating Open Files：dup()and dup2() 321

9.4.2 Creating Nonlinear Pipelines：/dev/fd/XX 326

9.4.3 Managing File Attributes：fcntl() 328

9.4.3.1 The Close-on-exec Flag 329

9.4.3.2 File Descriptor Duplication 331

9.4.3.3 Manipulation of File Status Flags and Access Modes 332

9.4.3.4 Nonblocking I/O for Pipes and FIFOs 333

9.4.3.5 fcntl()Summary 336

9.5 Example：Two-Way Pipes in gawk 337

9.6 Suggested Reading 341

9.7 Summary 342

Exercises 344

Chapter 10 Signals 347

10.1 Introduction 348

10.2 Signal Actions 348

10.3 Standard C Signals：signal()and raise() 349

10.3.1 The signal()Function 349

10.3.2 Sending Signals Programmatically：raise() 353

10.4 Signal Handlers in Action 353

10.4.1 Traditional Systems 353

10.4.2 BSD and GNU/Linux 356

10.4.3 Ignoring Signals 356

10.4.4 Restartable System Calls 357

10.4.4.1 Example：GNU Coreutils safe_read()and safe_write() 359

10.4.4.2 GLIBC Only：TEMP_FAILURE_RETRY() 360

10.4.5 Race Conditions and sig_atomic_t(ISO C) 361

10.4.6 Additional Caveats 363

10.4.7 Our Story So Far,Episode I 363

10.5 The System V Release 3 Signal APIs：sigset()et al 365

10.6 POSIX Signals 367

10.6.1 Uncovering the Problem 367

10.6.2 Signal Sets：sigset_t and Related Functions 368

10.6.3 Managing the Signal Mask：sigprocmask()et al 369

10.6.4 Catching Signals：sigaction() 370

10.6.5 Retrieving Pending Signals：sigpending() 375

10.6.6 Making Functions Interruptible：siginterrupt() 376

10.6.7 Sending Signals：kill()and killpg() 376

10.6.8 Our Story So Far.Episode Ⅱ 378

10.7 Signals for Interprocess Communication 379

10.8 Important Special-Purpose Signals 382

10.8.1 Alarm Clocks：sleep(),alarm(),and SIGALRM 382

10.8.1.1 Harder but with More Control：alarm()and SIGALRM 382

10.8.1.2 Simple and Easy：sleep() 383

10.8.2 Job Control Signals 383

10.8.3 Parental Supervision：Three Different Strategies 385

10.8.3.1 Poor Parenting：Ignoring Children Completely 385

10.8.3.2 Permissive Parenting：Supervising Minimally 386

10.8.3.3 Strict Parental Control 393

10.9 Signals Across fork()and exec() 398

10.10 Summary 399

Exercises 401

Chapter 11 Permissions and User and Group ID Numbers 403

11.1 Checking Permissions 404

11.1.1 Real and Effective IDs 405

11.1.2 Setuid and Setgid Bits 406

11.2 Retrieving User and Group IDs 407

11.3 Checking As the Real User：access() 410

11.4 Checking as the Effective User：euidaccess()(GLIBC) 412

11.5 Setting Extra Permission Bits for Directories 412

11.5.1 Default Group for New Files and Directories 412

11.5.2 Directories and the Sticky Bit 414

11.6 Setting Real and Effective IDs 415

11.6.1 Changing the Group Set 416

11.6.2 Changing the Real and Effective IDs 416

11.6.3 Using the Setuid and Setgid Bits 419

11.7 Working with All Three IDs：getresuid()and setresuid()(Linux) 421

11.8 Crossing a Security Minefield：Setuid root 422

11.9 Suggested Reading 423

11.10 Summary 424

Exercises 426

Chapter 12 General Library Interfaces—Part 2 427

12.1 Assertion Statements：assert() 428

12.2 Low-Level Memory：The memXXX()Functions 432

12.2.1 Setting Memory：memset() 432

12.2.2 Copying Memory：memcpy(),memmove(),and memccpy() 433

12.2.3 Comparing Memory Blocks：memcmp() 434

12.2.4 Searching for a Byte Value：memchr() 435

12.3 Temporary Files 436

12.3.1 Generating Temporary Filenames(Bad) 437

12.3.2 Creating and Opening Temporary Files(Good) 441

12.3.3 Using the TMPDIR Environment Variable 443

12.4 Committing Suicide：abort() 445

12.5 Nonlocal Gotos 446

12.5.1 Using Standard Functions：setjmp()and longjmp() 447

12.5.2 Handling Signal Masks：sigsetjmp()and siglongjmp() 449

12.5.3 Observing Important Caveats 450

12.6 Pseudorandom Numbers 454

12.6.1 Standard C：rand()and srand() 455

12.6.2 POSIX Functions：random()and srandom() 457

12.6.3 The/dev/random and/dev/urandom Special Files 460

12.7 Metacharacter Expansions 461

12.7.1 Simple Pattern Matching：fnmatch() 462

12.7.2 Filename Expansion：glob()and globfree() 464

12.7.3 Shell Word Expansion：wordexp()and wordfree() 470

12.8 Regular Expressions 471

12.9 Suggested Reading 480

12.10 Summary 481

Exercises 482

Chapter 13 Internationalization and Localization 485

13.1 Introduction 486

13.2 Locales and the C Library 487

13.2.1 Locale Categories and Environment Variables 487

13.2.2 Setting the Locale：setlocale() 489

13.2.3 String Collation：strcoll()and strxfrm() 490

13.2.4 Low-Level Numeric and Monetary Formatting：localeconv() 494

13.2.5 High-Level Numeric and Monetary Formatting：strfmon()and printf() 498

13.2.6 Example：Formatting Numeric Values in gawk 501

13.2.7 Formatting Date and Time Values：ctime()and strftime() 503

13.2.8 Other Locale Information：nl_langinfo() 504

13.3 Dynamic Translation of Program Messages 507

13.3.1 Setting the Text Domain：textdomain() 507

13.3.2 Translating Messages：gettext() 508

13.3.3 Working with Plurals：ngettext() 509

13.3.4 Making gettext()Easy to Use 510

13.3.4.1 Portable Programs："gettext.h: 511

13.3.4.2 GLIBC Only：＜libintl.h＞ 513

13.3.5 Rearranging Word Order with printf() 514

13.3.6 Testing Translations in a Private Directory 515

13.3.7 Preparing Internationalized Programs 516

13.3.8 Creating Translations 517

13.4 Can You Spell That for Me,Please? 521

13.4.1 Wide Characters 523

13.4.2 Multibyte Character Encodings 523

13.4.3 Languages 524

13.4.4 Conclusion 525

13.5 Suggested Reading 526

13.6 Summary 526

Exercises 527

Chapter 14 Extended Interfaces 529

14.1 Allocating Aligned Memory：posix_memalign()and memalign() 530

14.2 Locking Files 531

14.2.1 File Locking Concepts 531

14.2.2 POSIX Locking：fcntl()and lockf() 533

14.2.2.1 Describing a Lock 533

14.2.2.2 Obtaining and Releasing Locks 536

14.2.2.3 Observing Locking Caveats 538

14.2.3 BSD Locking：flock() 539

14.2.4 Mandatory Locking 540

14.3 More Precise Times 543

14.3.1 Microsecond Times：gettimeofday() 544

14.3.2 Microsecond File Times：utimes() 545

14.3.3 Interval Timers：setitimer()and getitimer() 546

14.3.4 More Exact Pauses：nanosleep() 550

14.4 Advanced Searching with Binary Trees 551

14.4.1 Introduction to Binary Trees 551

14.4.2 Tree Management Functions 554

14.4.3 Tree Insertion：tsearch() 554

14.4.4 Tree Lookup and Use of A Returned Pointer：tfind()and tsearch() 555

14.4.5 Tree Traversal：twalk() 557

14.4.6 Tree Node Removal and Tree Deletion：tdelete()and tdestroy() 561

14.5 Summary 562

Exercises 563

PART Ⅲ Debugging and Final project 565

Chapter 15 Debugging 567

15.1 First Things First 568

15.2 Compilation for Debugging 569

15.3 GDB Basics 570

15.3.1 Running GDB 571

15.3.2 Setting Breakpoints,Single-Stepping,and Setting Watchpoints 574

15.4 Programming for Debugging 577

15.4.1 Compile-Time Debugging Code 577

15.4.1.1 Use Debugging Macros 577

15.4.1.2 Avoid Expression Macros If Possible 580

15.4.1.3 Reorder Code If Necessary 582

15.4.1.4 Use Debugging Helper Functions 584

15.4.1.5 Avoid Unions When Possible 591

15.4.2 Runtime Debugging Code 595

15.4.2.1 Add Debugging Options and Variables 595

15.4.2.2 Use Special Environment Variables 597

15.4.2.3 Add Logging Code 601

15.4.2.4 Runtime Debugging Files 602

15.4.2.5 Add Special Hooks for Breakpoints 603

15.5 Debugging Tools 605

15.5.1 The dbug Library—A Sophisticated printf() 606

15.5.2 Memory Allocation Debuggers 612

15.5.2.1 GNU/Linux mtrace 613

15.5.2.2 Electric Fence 614

15.5.2.3 Debugging Malloc：dmalloc 619

15.5.2.4 Valgrind：A Versatile Tool 623

15.5.2.5 Other Malloc Debuggers 629

15.5.3 A Modern lint 631

15.6 Software Testing 632

15.7 Debugging Rules 633

15.8 Suggested Reading 637

15.9 Summary 638

Exercises 639

Chapter 16 A Project That Ties Everything Together 641

16.1 Project Description 642

16.2 Suggested Reading 644

PART Ⅳ Appendixes 647

Appendix A Teach Yourself Programming in Ten Years 649

Appendix B Caldera Ancient UNIX License 655

Appendix C GNU General Public License 657

Index 667