Linux programming by example : the fundamentals = Linux程序设计 /

preface

part i files and users

chapter 1 introduction

1.1 the linux/unix file model

1.1.1 files and permissions

1.1.2 directories and filenames

1.1.3 executable files

1.1.4 devices

1.2 the linux/unix process model

1.2.1 pipes: hooking processes together

1.3 standard c vs. original c

1.4 why gnu programs are better

1.4.1 program design

1.4.2 program behavior

1.4.3 c code programming

1.4.4 things that make a gnu program better

1.4.5 parting thoughts about the "gnu coding standards"

1.5 portability revisited

1.6 suggested reading

1.7 summary

.exercises

chapter 2 arguments, options, and the environment

2.1 option and argument conventions

2.1.1 posix conventions

2.1.2 gnu long options

2.2 basic command-line processing

2.2.1 the v7 echo program

2.3 option parsing: getopt ( ) and getope long ( )

2.3.1 single-letter options

2.3.2 gnu getopt ( ) and option ordering

2.3.3 long options

2.3.3.1 long options table

2.3.3.2 long options, posix style

2.3.3.3 getopt_long ( ) return value summary

2.3.3.4 gnu getopt ( ) or getopt long ( ) in user programs

2.4 the environment

2.4.1 environment management functions

2.4.2 the entire environment: environ

2.4.3 gnu env

2.5 summary

exercises

chapter 3 user-level memory management

3.1 linux/unix address space

3.2 memory allocation

3.2.1 library calls: malloe (), calloc ( ), realloc ( ), free ( )

3.2.1.1 examining c language details

3.2.1.2 initially allocating memory: malloc ( )

3.2.1.3 releasing memory: free ( )

3.2.1.4 changing size: realloc ( )

3.2.1.5 allocating and zero-filling: calloc ( )

3.2.1.6 summarizing from the gnu coding standards

3.2.1.7 using private allocators

3.2.1.8 example: reading arbitrarily long lines

3.2.1.9 glibc only: reading entire lines: getline ( ) and getdelim ( )

3.2.2 string copying: strdup ( )

3.2.3 system calls: brk ( ) and sbrk ( )

3.2.4 lazy programmer calls: alloea ( )

3.2.5 address space examination

3.3 summary

exercises

chapter 4 files and file i/o

4.1 introducing the linux/unix ilo model

4.2 presenting a basic program structure

4.3 determining what went wrong

4.3.1 values for errno

4.3.2 error message style

4.4 doing input and output

4.4.1 understanding file descriptors

4.4.2 opening and closing files

4.4.2.1 mapping file * variables to file descriptors

4.4.2.2 closing all open files

4.4.3 reading and writing

4.4.4 example: unix cat

4.5 random access: moving around within a file

4.6 creating files

4.6.1 specifying initial file permissions

4.6.2 creating files with creat ( )

4.6.3 revisiting open ( )

4.7 forcing data to disk

4.8 setting file length

4.9 summary

exercises

chapter s directories and file metadata

5.1 considering directory contents

5.1.1 definitions

5.1.2 directory contents

5.1.3 hard links

5.1.3.1 the gnu link program

5.1.3.2 dot and dot-dot

5.1.4 file renaming

5.1.5 file removal

5.1.5.1 removing open files

5.1.5.2 using iso c: remove ( )

5.1.6 symbolic links

5.2 creating and removing directories

5.3 reading directories

5.3.1 basic directory reading

5.3.1.1 portability considerations

5.3.1.2 linux and bsd directory entries

5.3.2 bsd directory positioning functions

5.4 obtaining information about files

5.4.1 linux file types

5.4.2 retrieving file information

5.4.3 linux only: specifying higher-precision file times

5.4.4 determining file type

5.4.4.1 device information

5.4.4.2 the v7 cat revisited

5.4.5 working with symbolic links

5.5 changing ownership, permission, and modification times

5.5.1 changing file ownership: chown (), fchown (), and lchown ( )

5.5.2 changing permissions: cb. mod ( ) and fchmod { )

5.5.3 changing timestamps: ut ime ( )

5.5.3.1 faking utime (file, null)

5.5.4 using fchown ( ) and fchmod ( ) for security

5.6 summary

exercises

chapter 6 general library interfaces -- part 1

6.1 times and dates

6.1.1 retrieving the current time: time ( ) and d i f f time ( )

6.1.2 breaking down times: gmtime ( ) and localtime ( )

6.1.3 formatting dates and times

6.1.3.1 simple time formatting: asctirae ( ) and crime ( )

6.1.3.2 complex time formatting: strftime ( )

6.1.4 converting a broken-down time to a time_t

6.1.5 getting time-zone information

6.1.5.1 bsd systems gotcha: timezone (), not timezone

6.2 sorting and searching functions

6.2.1 sorting: qsort ( ) .

6.2.1.1 example: sorting employees

6.2.1.2 example: sorting directory contents

6.2.2 binary searching: bsearch ( )

6.3 user and group names

6.3.1 user database

6.3.2 group database

6.4 terminals: isatty ( )

6.5 suggested reading

6.6 summary

exercises

chapter 7 putting it all together:. ls

7.1 v7 ls options

7.2 v7 ls code

7.3 summary

exercises

chapter 8 filesystems and directory walks

8. 1 mounting and unmounting filesystems

8.1.1 reviewing the background

8.1.2 looking at different filesystem types

8.1.3 mounting filesystems: mount

8.1.4 unmounting filesystems: umount

8.2 files for filesystem administration

8.2.1 using mount options

8.2.2 working with mounted filesystems: getrontent ( )

8.3 retrieving per-filesystem information

8.3.1 posix style: statvfs() and fstatvfs()

8.3.2 linux style: statfs( ) and fstatfs ( )

8.4 moving around in the file hierarchy

8.4.1 changing directory: chdir ( ) and fchdir ( )

8.4.2 getting the current directory: getcwd ( )

8.4.3 walking a hierarchy: nftw ( )

8.4.3.1 the nftw( ) interface

8.4.3.2 the nftw ( ) callback function

8.5 walking a file tree: gnu du

8.6 changing the root directory: ehroot ( )

8.7 summary

exercises

part ii processes, ipc, and internationalization

chapter 9 process management and pipes

9.1 process creation and management

9. 1. 1 creating a process: fork( )

9.1.1.1 after the fork( ): shared and distinct attributes

9.1.1.2 file descriptor sharing

9.1.1.3 file descriptor sharing and close ( )

9.1.2 identifying a process: getpid ( ) and getppid ( )

9.1.3 setting process priority: nice ( )

9.1.3.1 posix vs. reality

9.1.4 starting new programs: the exec ( ) family

9.1.4.1 the execve ( ) system call

9.1.4.2 wrapper functions: execl ( ) et al

9.1.4.3 program names and argv [0]

9.1.4.4 attributes inherited across exec ( )

9.1.5 terminating a process

9.1.5.1 defining process exit status

9.1.5.2 returning from main( )

9.1.5.3 exiting functions

9.1.6 recovering a child's exit status

9.1.6.1 using posix functions: wait ( ) and waitpid ( )

9.1.6.2 using bsd functions: wait3 ( ) and wait4 ( }

9.2 process groups

9.2.1 job control overview

9.2.2 process group identification: getpgrp ( ) and getpgid ( )

9.2.3 process group setting: setpgid ( ) and setpgrp ( )

9.3 basic interprocess communication: pipes and fifos

9.3.1 pipes

9.3.1.1 creating pipes

9.3.1.2 pipe buffering

9.3.2 fifos

9.4 file descriptor management

9.4.1 duplicating open files: dup ( ) and dup2 ( )

9.4.2 creating nonlinear pipelines: /der/fd/xx

9.4.3 managing file attributes: fentl ( )

9.4.3.1 the close-on-exec flag

9.4.3.2 file descriptor duplication

9.4.3.3 manipulation of file status flags and access modes

9.4.3.4 nonblocking i/o for pipes and fifos

9.4.3.5 fentl () summary

9.5 example: two-way pipes in gawk

9.6 suggested reading

9.7 summary

exercises

chapter 10 signals

10.1 introduction

10.2 signal actions

10.3 standard c signals: signal ( ) and raise ( )

10.3.1 the signal() function

10.3.2 sending signals programmatically: raise ( )

10.4 signal handlers in action

10.4.1 traditional systems

10.4.2 bsd and gnu/linux

10.4.3 ignoring signals

10.4.4 restartable system calls

10.4.4.1 example: gnu coreutils safe_read ( ) and safe_write ( )

10.4.4.2 glibc only: temp_failure_retry ( )

10.4.5 race conditions and sig_atomic_t (iso c)

10.4.6 additional caveats

10.4.7 our story so far, episode i

10.5 the system v release 3 signal apis: sigset ( ) et al

10.6 posix signals

10.6.1 uncovering the problem

10.6.2 signal sets: sigset_t and related functions

10.6.3 managing the signal mask: sigprocmask ( ) et al

10.6.4 catching signals: sigaction ( )

10.6.5 retrieving pending signals: sigpending ( )

10.6.6 making functions interruptible: siginterrupt ( )

10.6.7 sending signals: kill ( ) and killpg ( )

10.6.8 our story so far, episode ii

10.7 signals for interprocess communication

10.8 important special-purpose signals

10.8.1 alarm clocks: sleep ( ), alarm ( ), and sigalrm

10.8.1.1 harder but with more control: alarm ( ) and sigalrm

10.8.1.2 simple and easy: sleep ( )

10.8.2 job control signals

10.8.3 parental supervision: three different strategies

10.8.3.1 poor parenting: ignoring children completely

10.8.3.2 permissive parenting: supervising minimally

10.8.3.3 strict parental control

10.9 signals across fork ( ) and exec ( )

10.10 summary ~

exercises

chapter 11 permissions and user and group id numbers

11.1 checking permissions

11.1.1 real and effective ids

11.1.2 setuid and setgid bits

11.2 retrieving user and group ids

11.3 checking as the real user: access ( )

11.4 checking as the effective user: euidaccess ( ) (glibc)

! 1.5 setting extra permission bits for directories

11.5.1 default group for new files and directories

11.5.2 directories and the sticky bit

11.6 setting real and effective ids

11.6.1 changing the group set

11.6.2 changing the real and effective ids

11.6.3 using the setuid and setgid bits

11.7 working with all three ids: getresuid ( ) and setresuid ( ) (linux)

11.8 crossing a security minefield: setuid root

11.9 suggested reading

11.10 summary

exercises

chapter 12 general library interfaces -- part 2

12.1 assertion statements: assert ( )

12.2 low-level memory: the memxxx ( ) functions

12.2.1 setting memory: memset ( )

12.2.2 copying memory: memcpy (), memmove (), and memccpy ( }

12.2.3 comparing memory blocks: memcmp ( )

12.2.4 searching for a byte value: memehr ( )

12.3 temporary files

12.3.1 generating temporary filenames (bad)

12.3.2 creating and opening temporary files (good)

12.3.3 using the tmpdir environment variable

12.4 committing suicide: abort ( )

12.5 nonlocal gotos

12.5.1 using standard functions: setjmp ( ) and longjmp ( )

12.5.2 handling signal masks: sigsetjmp ( ) and siglongjmp ( )

12.5.3 observing important caveats

12.6 pseudorandom numbers

12.6.1 standard c: rand ( ) and srand ( )

12.6.2 posix functions: random ( ) and srandom ( )

12.6.3 the/dev/random and/dev/urandom special files

12.7 metacharacter expansions

12.7.1 simple pattern matching: fnmatch( )

12.7.2 filename expansion: glob ( ) and globfree ( )

12.7.3 shell word expansion: wordexp ( ) and wordfree ( )

12.8 regular expressions

12.9 suggested reading

12.10 summary

exercises

chapter 13 internationalization and localization

13.1 introduction

13.2 locales and the c library

13.2.1 locale categories and environment variables

13.2.2 setting the locale: setlocale()

13.2.3 string collation: strcoll ( ) and strxfrm()

13.2.4 low-level numeric and monetary formatting: localeconv ( )

13.2.5 high-level numeric and monetary formatting: strfmon ( )and print f ( )

13.2.6 example: formatting numeric values in gawk

13.2.7 formatting date and time values: ctime ( ) and strftime ( )

13.2.8 other locale information: nl_langinfo ( )

13.3 dynamic translation of program messages

13.3.1 setting the text domain: textdomain ( )

13.3.2 translating messages: gettext ( )

13.3.3 working with plurals: ngettext ( )

13.3.4 making gettext ( ) easy to use

13.3.4.1 portable programs: "gettext.h"
13.3.4.2 glibc only: [libintl.h]

13.3.5 rearranging word order with printf ( )

13.3.6 testing translations in a private directory

13.3.7 preparing internationalized programs

13.3.8 creating translations

13.4 can you spell that for me, please?

13.4.1 wide characters

13.4.2 multibyte character encodings

13.4.3 languages

13.4.4 conclusion

13.5 suggested reading

13.6 summary

exercises

chapter 14 extended interfaces

14.1 allocating aligned memory: posix memalign ( ) and memalign ( )

14.2 locking files

14.2.1 file locking concepts

14.2.2 posix locking: fcntl ( ) and locke ( )

14.2.2.1 describing a lock

14.2.2.2 obtaining and releasing locks

14.2.2.3 observing locking caveats

14.2.3 bsd locking: flock ()

14.2.4 mandatory locking

14.3 more precise times

14.3.1 microsecond times: gettimeofday( )

14.3.2 microsecond file times: utiraes ( )

14.3.3 interval timers: setitimer ( ) and getitimer ( )

14.3.4 more exact pauses: nanosleep ( )

14.4 advanced searching with binary trees

14.4.1 introduction to binary trees

14.4.2 tree management functions

14.4.3 tree insertion: tsearch()

14.4.4 tree lookup and use of a returned pointer: tfind ( ) andtsearch ( )

14.4.5 tree traversal: twalk( )

14.4.6 tree node removal and tree deletion: tdelete ( ) and tdestroy ( )

14.5 summary

exercises

part iii debugging and final project

chapter 15 debugging

15.1 first things first
15.2 compilation for debugging

15.3 gdb basics ~

15.3.1 running gdb

15.3.2 setting breakpoints, single-stepping, and setting watchpoints

15.4 programming for debugging

15.4.1 compile-time debugging code

15.4.1.1 use debugging macros

15.4.1.2 avoid expression macros if possible

15.4.1.3 reorder code if necessary

15.4.1.4 use debugging helper functions

15.4.1.5 avoid unions when possible

15.4.2 runtime debugging code

15.4.2.1 add debugging options and variables

15.4.2.2 use special environment variables

15.4.2.3 add logging code

15.4.2.4 runtime debugging files

15.4.2.5 add special hooks for breakpoints

15.5 debugging tools

15.5.1 the 0bug library—a sophisticated printf ( )

15.5.2 memory allocation debuggers

15.5.2.1 gnu/linux retrace

15.5.2.2 electric fence

15.5.2.3 debugging malloc: dmalloc

15.5.2.4 valgrind: a versatile tool

15.5.2.5 other malloc debuggers

15.5.3 a modern lint

15.6 software testing

15.7 debugging rules

15.8 suggested reading

15.9 summary

exercises

chapter 16 a project that ties everything together
16.1 project description

16.2 suggested reading

part iv appendixes

appendix a teach yourself programming in ten years

appendix b caldera ancient unix license

appendix c gnu general public license

index