Advanced Programming in the UNIX Environment W. Richard Stevens

Transcription

1 Advanced Programming in the UNIX Environment W. Richard Stevens ADDISON-WESLEY PUBLISHING COMPANY Reading, Massachusetts Menlo Park, California New York Don Mills, Ontario Wokingham, England Amsterdam Bonn Sydney Singapore Tokyo Madrid San Juan Paris Seoul Milan Mexico City Taipei

2 Preface Chapter Chapter Introduction Introduction 1 Logging In 1 Files and Directories 3 Input and Output 6 Programs and Processes 9 ANSI C Features 12 Error Handling 14 User Identification 16 Signals 17 Unix Time Values 19 System Calls and Library Functions 20 Summary 23 Unix Standardization and Implementations Introduction 25 Unix Standardization ANSI C IEEE POSIX X/Open XPG FIPS 28 Unix Implementations System V Release BSD xv 1 25 Vll

3 V1U 2.4 Relationship of Standards and Implementations Limits ANSI C Limits POSIX Limits XPG3 Limits sysconf, pathconf, and fpathconf Functions FIPS Requirements Summary of Limits Indeterminate Run-Time Limits Feature Test Macros Primitive System Data Types Conflicts Between Standards Summary 46 Chapter File I/O Introduction 47 File Descriptors open Function creat Function close Function lseek Function read Function write Function I/O Efficiency File Sharing Atomic Operations 60 dup and dup2 Functions fcntl Function 63 ioctl Function 67 /dev/fd 69 Summary Chapter 4. Files and Directories 4.1 Introduction stat, fstat, and lstat Functions 4.3 File Types Set-User-ID and Set-Group-ID File Access Permissions Ownership of New Files and Directories 4.7 access Function umask Function chmod and fchmod Functions Sticky Bit chown, fchown, and lchown Functions

4 File Size 90 File Truncation 91 Filesystems 92 link, unlink, remove, and rename Functions Symbolic Links 99 symlink and readlink Functions 102 File Times 102 utime Function 103 mkdir and rmdir Functions 106 Reading Directories 107 chdir, fchdir, and getcwd Functions 112 Special Device Files 114 sync and fsync Functions 116 Summary of File Access Permission Bits Summary Chapter Chapter Standard I/O Library Introduction 121 Streams and FILE Objects 121 Standard Input, Standard Output, and Standard Error Buffering 122 Opening a Stream 125 Reading and Writing a Stream 127 Line-at-a-Time I/O 130 Standard I/O Efficiency 131 Binary I/O 133 Positioning a Stream 135 Formatted I/O 136 Implementation Details 138 Temporary Files 140 Alternatives to Standard I/O 143 Summary 143 System Data Files and Information Introduction 145 Password File 145 Shadow Passwords 148 Group File 149 Supplementary Group IDs 150 Other Data Files 152 Login Accounting 153 System Identification 154 Time and Date Routines 155 Summary

5 Chapter 7. Chapter 8. Chapter 9. The Environment of a Unix Process 7.1 Introduction main Function Process Termination Command-Line Arguments Environment List Memory Layout of a C Program Shared Libraries Memory Allocation Environment Variables setjmp and longjmp Functions getrlimit and setrlimit Functions Summary 184 Process Control 8.1 Introduction Process Identifiers fork Function vfork Function exit Functions wait and waitpid Functions wait3 and wait4 Functions Race Conditions exec Functions Changing User IDs and Group IDs Interpreter Files system Function Process Accounting User Identification Process Times Summary 235 Process Relationships 9.1 Introduction Terminal Logins Network Logins Process Groups Sessions Controlling Terminal tcgetpgrp and tcsetpgrp Functions Job Control Shell Execution of Programs

6 XI 9.10 Orphaned Process Groups BSD Implementation Summary 261 Chapter 10. Signals Introduction Signal Concepts signal Function Unreliable Signals Interrupted System Calls Reentrant Functions SIGCLD Semantics Reliable Signal Terminology and Semantics kill and raise Functions alarm and pause Functions Signal Sets sigprocmask Function sigpending Function sigaction Function sigsetjmp and siglongjmp Functions sigsuspend Function abort Function system Function sleep Function Job-Control Signals Additional Features Summary 323 Chapter 11. Terminal I/O Introduction Overview Special Input Characters Getting and Setting Terminal Attributes Terminal Option Flags stty Command Baud Rate Functions Line Control Functions Terminal Identification Canonical Mode Noncanonical Mode Terminal Window Size termcap, terminfo, and curses Summary 360

7 XU Chapter 12. Advanced I/O Introduction 363 Nonblocking I/O 363 Record Locking 367 Streams 383 I/O Multiplexing select Function poll Function 400 Asynchronous I/O System V Release BSD 403 readv and writev Functions 404 readn and writen Functions 406 Memory Mapped I/O 407 Summary 413 Chapter Daemon Processes Introduction 415 Daemon Characteristics 415 Coding Rules 417 Error Logging SVR4 Streams log Driver BSD syslog Facility Client-Server Model 424 Summary Chapter 14. Interprocess Communication 14.1 Introduction Pipes popen and pclose Functions Coprocesses FIFOs System V IPC Identifiers and Keys Permission Structure Configuration Limits Advantages and Disadvantages 14.7 Message Queues Semaphores Shared Memory Client-Server Properties Summary

8 xiu Chapter 15. Chapter 16. Chapter 17. Chapter 18. Advanced Interprocess Communication 15.1 Introduction Stream Pipes Passing File Descriptors System V Release BSD BSD An Open Server, Version Client-Server Connection Functions System V Release BSD An Open Server, Version Summary 514 A Database Library 16.1 Introduction History The Library Implementation Overview Centralized or Decentralized? Concurrency Source Code Performance Summary 550 Communicating with a PostScript Printer 17.1 Introduction PostScript Communication Dynamics Printer Spooling Source Code Summary 578 A Modem Dialer 18.1 Introduction History Program Design Data Files Server Design Server Source Code Client Design Client Source Code Summary

9 XIV Chapter Appendix A. Appendix B. B.1 B.2 Appendix C. Bibliography Index Pseudo Terminals Introduction 631 Overview 631 Opening Pseudo-Terminal Devices System V Release BSD 640 pty_fork Function 641 pty Program 644 Using the pty Program 648 Advanced Features 655 Summary 656 Function Prototypes Miscellaneous Source Code Our Header File 679 Standard Error Routines 681 Solutions to Selected Exercises