Chapter 1.UNIX System Overview 1
1.1 Introduction 1
1.2 UNIX Architecture 1
1.3 Logging In 2
1.4 Files and Directories 4
1.5 Input and Output 8
1.6 Programs and Processes 10
1.7 Error Handling 14
1.8 User Identification 16
1.9 Signals 18
1.10 Time Values 20
1.11 System Calls and Library Functions 21
1.12 Summary 23
Chapter 2.UNIX Standardization and Implementations 25
2.1 Introduction 25
2.2 UNIX Standardization 25
2.2.1 ISO C 25
2.2.2 IEEE POSIX 26
2.2.3 The Single UNIX Specification 29
2.2.4 FIPS 33
2.3 UNIX System Implementations 33
2.3.1 UNIX System V Release 4 33
2.3.2 4.4BSD 34
2.3.3 FreeBSD 35
2.3.4 Linux 35
2.3.5 Mac OS X 35
2.3.6 Solaris 35
2.3.7 Other UNIX Systems 36
2.4 Relationship of Standards and Implementations 36
2.5 Limits 36
2.5.1 ISO C Limits 38
2.5.2 POSIX Limits 38
2.5.3 XSI Limits 40
2.5.4 sysconf, pathconf, and fpathconf Functions 41
2.5.5 Indeterminate Runtime Limits 48
2.6 Options 52
2.7 Feature Test Macros 55
2.8 Primitive System Data Types 56
2.9 Conflicts Between Standards 56
2.10 Summary 58
Chapter 3. File I/O 59
3.1 Introduction 59
3.2 File Descriptors 59
3.3 open Function 60
3.4 creat Function 62
3.5 close Function 63
3.6 lseek Function 63
3.7 read Function 67
3.8 write Function 68
3.9 I/O Efficiency 68
3.10 File Sharing 70
3.11 Atomic Operations 74
3.12 dup and dup2 Functions 76
3.13 sync, fsync, and fdatasync Functions 77
3.14 fcntl Function 78
3.15 ioctl Function 83
3.16 /dev/fd 84
3.17 Summary 85
Chapter 4. Files and Directories 87
4.1 Introduction 87
4.2 stat, fstat, and lstat Functions 87
4.3 File Types 88
4.4 Set-User-ID and Set-Group-ID 91
4.5 File Access Permissions 92
4.6 Ownership of New Files and Directories 95
4.7 access Function 95
4.8 umask Function 97
4.9 chmod and fchmod Functions 99
4.10 Sticky Bit 101
4.11 chown, fchown, and lchown Functions 102
4.12 File Size 103
4.13 File Truncation 105
4.14 File Systems 105
4.15 link, unlink, remove, and rename Functions 108
4.16 Symbolic Links 112
4.17 symlink and readlink Functions 115
4.18 File Times 115
4.19 utime Function 116
4.20 mkdir and rmdir Functions 119
4.21 Reading Directories 120
4.22 chdir, fchdir, and getcwd Functions 125
4.23 Device Special Files 127
4.24 Summary of File Access Permission Bits 130
4.25 Summary 130
Chapter 5. Standard I/O Library 133
5.1 Introduction 133
5.2 Streams and FILE Objects 133
5.3 Standard Input, Standard Output, and Standard Error 135
5.4 Buffering 135
5.5 Opening a Stream 138
5.6 Reading and Writing a Stream 140
5.7 Line-at-a-Time I/O 142
5.8 Standard I/O Efficiency 143
5.9 Binary I/O 145
5.10 Positioning a Stream 147
5.11 Formatted I/O 149
5.12 Implementation Details 153
5.13 Temporary Files 155
5.14 Alternatives to Standard I/O 159
5.15 Summary 159
Chapter 6. System Data Files and Information 161
6.1 Introduction 161
6.2 Password File 161
6.3 Shadow Passwords 165
6.4 Group File 166
6.5 Supplementary Group IDs 167
6.6 Implementation Differences 169
6.7 Other Data Files 169
6.8 Login Accounting 170
6.9 System Identification 171
6.10 Time and Date Routines 173
6.11 Summary 177
Chapter 7. Process Environment 179
7.1 Introduction 179
7.2 main Function 179
7.3 Process Termination 180
7.4 Command-Line Arguments 185
7.5 Environment List 185
7.6 Memory Layout of a C Program 186
7.7 Shared Libraries 188
7.8 Memory Allocation 189
7.9 Environment Variables 192
7.10 setjmp and longjmp Functions 195
7.11 getrlimit and setrlimit Functions 202
7.12 Summary 206
Chapter 8. Process Control 209
8.1 Introduction 209
8.2 Process Identifiers 209
8.3 fork Function 211
8.4 vfork Function 216
8.5 exit Functions 218
8.6 wait and waitpid Functions 220
8.7 waitid Function 226
8.8 wait3 and wait4 Functions 227
8.9 Race Conditions 227
8.10 exec Functions 231
8.11 Changing User IDs and Group IDs 237
8.12 Interpreter Files 242
8.13 system Function 246
8.14 Process Accounting 250
8.15 User Identification 256
8.16 Process Times 257
8.17 Summary 259
Chapter 9. Process Relationships 261
9.1 Introduction 261
9.2 Terminal Logins 261
9.3 Network Logins 266
9.4 Process Groups 269
9.5 Sessions 270
9.6 Controlling Terminal 272
9.7 tcgetpgrp, tcsetpgrp, and tcgetsid Functions 273
9.8 Job Control 274
9.9 Shell Execution of Programs 278
9.10 Orphaned Process Groups 282
9.11 FreeBSD Implementation 285
9.12 Summary 287
Chapter 10. Signals 289
10.1 Introduction 289
10.2 Signal Concepts 289
10.3 signal Function 298
10.4 Unreliable Signals 301
10.5 Interrupted System Calls 303
10.6 Reentrant Functions 305
10.7 SIGCLD Semantics 308
10.8 Reliable-Signal Terminology and Semantics 310
10.9 kill and raise Functions 311
10.10 alarm and pause Functions 313
10.11 Signal Sets 318
10.12 sigprocmask Function 320
10.13 s igpending Function 322
10.14 sigaction Function 324
10.15 sigsetjmp and siglongjmp Functions 329
10.16 sigsuspend Function 333
10.17 abort Function 340
10.18 system Function 342
10.19 sleep Function 347
10.20 Job-Control Signals 349
10.21 Additional Features 352
10.22 Summary 353
Chapter 11. Threads 355
11.1 Introduction 355
11.2 Thread Concepts 355
11.3 Thread Identification 356
11.4 Thread Creation 357
11.5 Thread Termination 360
11.6 Thread Synchronization 368
11.7 Summary 385
Chapter 12. Thread Control 387
12.1 Introduction 387
12.2 Thread Limits 387
12.3 Thread Attributes 388
12.4 Synchronization Attributes 393
12.5 Reentrancy 401
12.6 Thread-Specific Data 406
12.7 Cancel Options 410
12.8 Threads and Signals 413
12.9 Threads and fork 416
12.10 Threads and I/O 420
12.11 Summary 420
Chapter 13. Daemon Processes 423
13.1 Introduction 423
13.2 Daemon Characteristics 423
13.3 Coding Rules 425
13.4 Error Logging 428
13.5 Single-Instance Daemons 432
13.6 Daemon Conventions 434
13.7 Client-Server Model 439
13.8 Summary 439
Chapter 14. Advanced I/O 441
14.1 Introduction 441
14.2 Nonblocking I/O 441
14.3 Record Locking 444
14.4 STREAMS 460
14.5 I/O Multiplexing 472
14.5.1 select and pselect Functions 474
14.5.2 poll Function 479
14.6 Asynchronous I/O 481
14.6.1 System V Asynchronous I/O 481
14.6.2 BSD Asynchronous I/O 482
14.7 readv and writev Functions 483
14.8 readn and writen Functions 485
14.9 Memory-Mapped I/O 487
14.10 Summary 492
Chapter 15. Interprocess Communication 495
15.1 Introduction 495
15.2 Pipes 496
15.3 popen and pclose Functions 503
15.4 Coprocesses 510
15.5 FIFOs 514
15.6 XSI IPC 518
15.6.1 Identifiers and Keys 518
15.6.2 Permission Structure 520
15.6.3 Configuration Limits 521
15.6.4 Advantages and Disadvantages 521
15.7 Message Queues 522
15.8 Semaphores 527
15.9 Shared Memory 533
15.10 Client-Server Properties 541
15.11 Summary 543
Chapter 16. Network IPC: Sockets 545
16.1 Introduction 545
16.2 Socket Descriptors 546
16.3 Addressing 549
16.3.1 Byte Ordering 549
16.3.2 Address Formats 551
16.3.3 Address Lookup 553
16.3.4 Associating Addresses with Sockets 560
16.4 Connection Establishment 561
16.5 Data Transfer 565
16.6 Socket Options 579
16.7 Out-of-Band Data 581
16.8 Nonblocking and Asynchronous I/O 582
16.9 Summary 583
Chapter 17. Advanced IPC 585
17.1 Introduction 585
17.2 STREAMS-Based Pipes 585
17.2.1 Naming STREAMS Pipes 589
17.2.2 Unique Connections 590
17.3 UNIX Domain Sockets 594
17.3.1 Naming UNIX Domain Sockets 595
17.3.2 Unique Connections 597
17.4 Passing File Descriptors 601
17.4.1 Passing File Descriptors over STREAMS-Based Pipes 604
17.4.2 Passing File Descriptors over UNIX Domain Sockets 606
17.5 An Open Server, Version 1 615
17.6 An Open Server, Version 2 620
17.7 Summary 629
Chapter 18. Terminal I/O 631
18.1 Introduction 631
18.2 Overview 631
18.3 Special Input Characters 638
18.4 Getting and Setting Terminal Attributes 643
18.5 Terminal Option Flags 643
18.6 stty Command 651
18.7 Baud Rate Functions 652
18.8 Line Control Functions 653
18.9 Terminal Identification 654
18.10 Canonical Mode 660
18.11 Noncanonical Mode 663
18.12 Terminal Window Size 670
18.13 termcap, terminfo, and curses 672
18.14 Summary 673
Chapter 19. Pseudo Terminals 675
19.1 Introduction 675
19.2 Overview 675
19.3 Opening Pseudo-Terminal Devices 681
19.3.1 STREAMS-Based Pseudo Terminals 683
19.3.2 BSD-Based Pseudo Terminals 686
19.3.3 Linux-Based Pseudo Terminals 689
19.4 pty_fork Function 691
19.5 pty Program 694
19.6 Using the pty Program 698
19.7 Advanced Features 705
19.8 Summary 706
Chapter 20. A Database Library 709
20.1 Introduction 709
20.2 History 709
20.3 The Library 710
20.4 Implementation Overview 712
20.5 Centralized or Decentralized? 716
20.6 Concurrency 718
20.7 Building the Library 719
20.8 Source Code 719
20.9 Performance 747
20.10 Summary 752
Chapter 21. Communicating with a Network Printer 753
21.1 Introduction 753
21.2 The Internet Printing Protocol 753
21.3 The Hypertext Transfer Protocol 756
21.4 Printer Spooling 757
21.5 Source Code 758
21.6 Summary 805
Appendix A. Function Prototypes 807
Appendix B. Miscellaneous Source Code 843
B.1 Our Header File 843
B.2 Standard Error Routines 846
Appendix C. Solutions to Selected Exercises 853
Bibliography 885
Index 891