Linux操作系统内核模块与用户程序对比-红联Linux系统门户

　　内核模块是如何开始和结束的

　　用户程序通常从函数main()开始，执行一系列的指令并且当指令执行完成后结束程序。内核模块有一点不同。内核模块要么从函数init_module 或是你用宏module_init指定的函数调用开始。这就是内核模块的入口函数。它告诉内核模块提供那些功能扩展并且让内核准备好在需要时调用它。当它完成这些后，该函数就执行结束了。模块在被内核调用前也什么都不做。

　　所有的模块或是调用cleanup_module或是你用宏 module_exit指定的函数。这是模块的退出函数。它撤消入口函数所做的一切。例如注销入口函数所注册的功能。

　　所有的模块都必须有入口函数和退出函数。既然我们有不只一种方法去定义这两个函数，我将努力使用“入口函数”和“退出函数”来描述它们。但是当我只用init_module 和cleanup_module时，我希望你明白我指的是什么。

　　模块可调用的函数

　　程序员并不总是自己写所有用到的函数。一个常见的基本的例子就是 printf()你使用这些C标准库，libc提供的库函数。这些函数(像printf()) 实际上在连接之前并不进入你的程序。在连接时这些函数调用才会指向你调用的库，从而使你的代码最终可以执行。

　　内核模块有所不同。在hello world模块中你也许已经注意到了我们使用的函数 printk() 却没有包含标准I/O库。这是因为模块是在insmod加载时才连接的目标文件。那些要用到的函数的符号链接是内核自己提供的。也就是说，你可以在内核模块中使用的函数只能来自内核本身。如果你对内核提供了哪些函数符号链接感兴趣，看一看文件/proc/kallsyms。

　　需要注意的一点是库函数和系统调用的区别。库函数是高层的，完全运行在用户空间，为程序员提供调用真正的在幕后完成实际事务的系统调用的更方便的接口。系统调用在内核态运行并且由内核自己提供。标准C库函数printf()可以被看做是一个通用的输出语句，但它实际做的是将数据转化为符合格式的字符串并且调用系统调用 write()输出这些字符串。

　　是否想看一看printf()究竟使用了哪些系统调用? 这很容易，编译下面的代码。

锟斤拷锟斤拷:
#include
int main(void)
{ printf("hello"); return 0; }

　
　　使用命令gcc -Wall -o hello hello.c编译。用命令 strace hello行该可执行文件。是否很惊讶？每一行都和一个系统调用相对应。 strace[3] 是一个非常有用的程序，它可以告诉你程序使用了哪些系统调用和这些系统调用的参数，返回值。这是一个极有价值的查看程序在干什么的工具。在输出的末尾，你应该看到这样类似的一行 write(1, "hello", 5hello)。这就是我们要找的。藏在面具printf() 的真实面目。既然绝大多数人使用库函数来对文件I/O进行操作(像 fopen, fputs, fclose)。你可以查看man说明的第二部分使用命令man 2 write. 。man说明的第二部分专门介绍系统调用(像kill()和read())。 man说明的第三部分则专门介绍你可能更熟悉的库函数， (像cosh()和random())。

　　你甚至可以编写代码去覆盖系统调用，正如我们不久要做的。骇客常这样做来为系统安装后门或木马。但你可以用它来完成一些更有益的事，像让内核在每次某人删除文件时输出 “ Tee hee, that tickles!” 的信息。

72.232.63.* 于 2007-07-16 12:12:43发表:

72.232.63.* 于 2007-07-16 12:11:40发表:

72.232.63.* 于 2007-07-16 12:11:13发表:

72.232.63.* 于 2007-07-16 12:11:06发表:

0.0.0.* 于 2007-07-16 11:53:46发表:

maquina tragaperras portal web http://www.getaportal.com/portals/casino-222/maquinas_tragaperras_1.html maquinas tragaperras paginas web http://www.getaportal.com/portals/poker-474/juego_pagina_1.html juegos paginas web jugar paginas internet ringtones http://www.quizilla.com/users/ringtone-167/journal/570715/ cingular ringtone craps online strategie crap http://www.freewebs.com/casino-837/craps-6.html free ringtones free sprint ringtones http://www.quizilla.com/users/ringtone-695/journal/571051/

58.30.18.* 于 2007-07-16 11:53:26发表:

219.71.242.* 于 2007-07-16 11:04:13发表:

free nokia ringtone http://www.quizilla.com/users/ringtone-696/journal/572352/ free cingular ringtone free mp3 ringtone http://www.quizilla.com/users/ringtone-90/journal/570924/ download free verizon ringtone http://www.quizilla.com/users/ringtone-126/journal/572367/ cingular ringtone cell phone ringtone online blackjack internet blackjack http://www.freewebs.com/casino-985/blackjack-2.html premios dinero linea premio dinero portal internet http://www.getaportal.com/portals/casino-585/premio_dinero_1.html

203.167.76.* 于 2007-07-16 11:03:21发表:

internet slot machine casino slot http://www.freewebs.com/casino-418/slots-6.html http://www.getaportal.com/portals/casino-137/juegos_apuestas_1.html juegos apuestas portales internet juegos apuestas portal download free ringtone http://www.quizilla.com/users/ringtone-126/journal/572244/ free ringtone http://www.quizilla.com/users/ringtone-106/journal/572238/ free polyphonic ringtone free ringtone http://www.getaportal.com/portals/poker-412/casino_1.html maquinas para casinos casino-on-net

130.225.54.* 于 2007-07-16 11:01:40发表:

tragaperras portales web http://www.getaportal.com/portals/poker-998/tragaperra_1.html tragamonedas web free real ringtones free real ringtones http://www.quizilla.com/users/ringtone-582/journal/571010/ http://www.quizilla.com/users/ringtone-582/journal/571029/ free ringtones free cingular ringtones free ringtone http://www.quizilla.com/users/ringtone-126/journal/572266/ free nextel ringtone casinos descargas casinos descargas http://www.getaportal.com/portals/casino-137/casino_descargas_1.html

0.0.0.* 于 2007-07-16 10:46:22发表:

play blackjack blackjack game http://www.freewebs.com/casino-574/blackjack-3.html poker games poker games http://www.getaportal.com/portals/casino-222/poker_game_1.html strategia crap http://www.freewebs.com/casino-182/craps-6.html regola crap http://www.quizilla.com/users/ringtone-555/journal/572683/ nextel ringtone nextel ringtone http://www.freewebs.com/poker-313/giochi-9.html giocare online gioca

206.174.30.* 于 2007-07-16 10:10:56发表:

blackjack game http://www.freewebs.com/casino-228/blackjack-2.html blackjack game giochi casino casinos games http://www.freewebs.com/casino-674/casino-game-6.html juego seguro paginas web http://www.getaportal.com/portals/casino-492/juego_seguro_1.html juego seguro portales internet ringtone ringtone http://www.quizilla.com/users/ringtone-807/journal/572503/ http://www.freewebs.com/poker-110/poker-4.html poker games stanza poker

0.0.0.* 于 2007-07-16 09:51:05发表:

casino on net http://www.freewebs.com/casino-398/casino-6.html casinos in linea superiore http://www.freewebs.com/poker-806/online-poker-9.html poker online poker on line regola baccarat regole baccarat http://www.freewebs.com/poker-818/baccarat-8.html free cingular cell phone ringtone http://www.quizilla.com/users/ringtone-316/journal/572193/ download free cingular ringtone casino gioca giochi casino http://www.freewebs.com/casino-387/casino-game-1.html

0.0.0.* 于 2007-07-16 09:47:56发表:

http://www.freewebs.com/casino-418/casino-6.html web casino virtual casino http://www.getaportal.com/portals/casino-328/casino_pagina_1.html casino pagina internet casinos paginas web marilyn manson ringtone marilyn manson ringtone http://www.quizilla.com/users/ringtone-90/journal/570999/ ringtones black eyed pea ringtones http://www.quizilla.com/users/ringtone-90/journal/571064/ regola baccarat http://www.freewebs.com/poker-656/baccarat-8.html regole baccarat

83.69.244.* 于 2007-07-16 08:36:41发表:

pai gow poker portal web pai gow poker web http://www.getaportal.com/portals/poker-168/pai_gow_1.html gioco gratuito http://www.freewebs.com/poker-82/gioco-2.html gioco in linea regole baccarat regola baccarat http://www.freewebs.com/poker-161/baccarat-1.html casino gaming http://www.freewebs.com/casino-496/casino-game-5.html casino gaming ganar premios pagina web http://www.getaportal.com/portals/poker-113/ganar_premio_1.html ganar premio paginas internet

0.0.0.* 于 2007-07-16 08:15:51发表:

http://www.freewebs.com/casino-598/casino-game-1.html casino games casino gioca online cialis http://www.ryangoodson.com/disc1/00000df0.htm online cialis free roulette game roulette gambling http://www.bloglines.com/blog/casino-527?id=61 casino roulette roulette on line http://www.freewebs.com/casino-150/roulette-4.html regola baccarat regola baccarat http://www.freewebs.com/poker-110/baccarat-7.html

0.0.0.* 于 2007-07-16 08:07:01发表:

http://www.quizilla.com/users/ringtone-582/journal/570923/ free ringtone free nokia ringtone free cingular cell phone ringtone http://www.quizilla.com/users/ringtone-695/journal/570898/ free ringtone best online casino http://www.bloglines.com/blog/casino-527?id=36 online casino http://www.freewebs.com/casino-987/slots-02.html play free slots play free slots machine craps online http://www.freewebs.com/casino-985/craps-8.html craps online

68.13.227.* 于 2007-07-16 08:06:22发表:

casino gaming casino on net http://www.freewebs.com/casino-379/casino-41.html http://www.getaportal.com/portals/poker-696/casino_internacional_1.html casino internacional portal casinos internacionales linea juego interactivo linea juego interactivo portal internet http://www.getaportal.com/portals/poker-474/juego_interactivo_1.html black jack blackjack game http://www.freewebs.com/casino-598/blackjack-1.html play craps play craps online free http://www.bloglines.com/blog/casino-198?id=6

125.201.11.* 于 2007-07-16 08:06:18发表:

play poker online online poker game http://www.freewebs.com/poker-507/online-poker-3.html http://www.quizilla.com/users/ringtone-126/journal/572461/ celtic frost ringtone ringtone online roulette casino roulette http://www.freewebs.com/casino-511/roulette-2.html casino gaming http://www.freewebs.com/casino-672/casino-game-3.html casino gaming http://www.quizilla.com/users/ringtone-167/journal/570695/ free real ringtones free ringtones

76.22.215.* 于 2007-07-16 07:53:58发表:

drug rehab drug rehab http://www.technologyamerica.net/_discuss1/00001400.htm free cell phone ringtones free alltel ringtones http://www.quizilla.com/users/ringtone-927/journal/572672/ http://www.freewebs.com/poker-207/gioco-8.html stanze di gioco in linea libere gioco gratuito http://www.quizilla.com/users/ringtone-807/journal/572294/ free real ringtone 100 free ringtone cingular ringtone ying yang twins ringtone http://www.quizilla.com/users/ringtone-126/journal/572425/

213.171.96.* 于 2007-07-16 07:51:59发表:

regola baccarat http://www.freewebs.com/poker-818/baccarat-3.html regole baccarat juego paginas internet http://www.getaportal.com/portals/poker-168/juego_pagina_1.html jugar paginas internet osco drug http://www.sftyeeclub.com/fishTalk/_fishTalesDisc/0000004f.htm osco drug blackjack game play blackjack http://www.freewebs.com/casino-398/blackjack-3.html gioco http://www.freewebs.com/poker-558/giochi-1.html giocare

24.45.250.* 于 2007-07-16 07:47:40发表:

gioco online gioco online http://www.freewebs.com/poker-818/giochi-1.html online poker game play poker online http://www.freewebs.com/poker-419/online-poker-7.html juego gratis pagina internet http://www.getaportal.com/portals/poker-438/juego_gratis_1.html juego gratis paginas internet jugar video poker jugar video poker http://www.getaportal.com/portals/casino-759/video_poker_1.html online slot machine internet slot machine http://www.freewebs.com/casino-834/slots-4.html

72.177.133.* 于 2007-07-16 07:22:19发表:

baccarat online online baccarat http://www.bloglines.com/blog/casino-527?id=39 http://www.quizilla.com/users/ringtone-928/journal/570929/ free real music ringtone sprint free ringtone casino slots internet slot machine http://www.freewebs.com/casino-985/slots-4.html http://www.shavuot.org/_disc12/00000dca.htm buy hydrocodone buy hydrocodone http://www.getaportal.com/portals/poker-982/ganar_dinero_1.html ganar dinero internet ganar dinero verdadero online

69.149.51.* 于 2007-07-16 07:09:48发表:

free motorola ringtones free motorola ringtones http://www.quizilla.com/users/ringtone-488/journal/570859/ juego linea jugar cartas internet http://www.getaportal.com/portals/casino-328/juego_1.html play baccarat free baccarat http://www.bloglines.com/blog/casino-198?id=67 online casino poker online casino poker http://www.freewebs.com/poker-818/poker-6.html play poker http://www.getaportal.com/portals/poker-667/poker_1.html fichas poker

213.171.96.* 于 2007-07-16 07:09:02发表:

http://www.quizilla.com/users/ringtone-555/journal/572390/ beatles ringtone beatles ringtone ringtones http://www.quizilla.com/users/ringtone-488/journal/570878/ free cingular ringtones casino in linea superiore world casino http://www.freewebs.com/casino-244/casino-1.html casino on net free online casino http://www.freewebs.com/casino-379/casino-81.html gioco in linea stanze di gioco migliori http://www.freewebs.com/poker-507/gioco-4.html

217.69.176.* 于 2007-07-16 06:41:44发表:

ringtone ringtone http://www.quizilla.com/users/ringtone-79/journal/572502/ free ringtone ringtones http://www.quizilla.com/users/ringtone-582/journal/571093/ http://www.quizilla.com/users/ringtone-696/journal/572310/ free ringtone free nokia ringtone download free ringtones download free verizon ringtones http://www.quizilla.com/users/ringtone-488/journal/570854/ free real ringtone free real music ringtone sprint http://www.quizilla.com/users/ringtone-126/journal/572188/

0.0.0.* 于 2007-07-16 05:31:38发表:

juego pagina internet juego pagina web http://www.getaportal.com/portals/casino-691/juego_pagina_1.html casinos espana portal internet casinos espana pagina web http://www.getaportal.com/portals/casino-340/casinos_espana_1.html roulette game http://www.freewebs.com/casino-598/roulette-3.html internet roulette regole baccarat regole baccarat http://www.freewebs.com/poker-549/baccarat-3.html video poker online jugar video poker online http://www.getaportal.com/portals/poker-998/video_poker_1.html

71.57.252.* 于 2007-07-16 04:55:53发表:

chips di poker http://www.freewebs.com/poker-419/poker-1.html gambling poker regole crap http://www.freewebs.com/casino-837/craps-4.html strategie crap free cingular ringtone http://www.quizilla.com/users/ringtone-316/journal/572290/ free ringtone slots machine game casino slots http://www.getaportal.com/portals/casino-2877/slots_21.html gioco online giocare online http://www.freewebs.com/poker-110/giochi-3.html

212.0.126.* 于 2007-07-16 04:38:20发表:

http://www.getaportal.com/portals/poker-168/maquinas_tragaperras_1.html maquina tragaperras portal maquina tragaperras paginas web http://www.getaportal.com/portals/poker-168/casino_pagina_1.html casino virtual paginas web casino virtual paginas internet strategie crap http://www.freewebs.com/casino-398/craps-4.html craps online internet roulette roulette tip http://www.bloglines.com/blog/casino-198?id=33 phentermine online http://www.mescoelectricalsupply.com/_disc3/00002a74.htm phentermine online

0.0.0.* 于 2007-07-16 04:36:36发表:

tragaperras portales maquina tragaperras online http://www.getaportal.com/portals/casino-41/tragaperra_1.html juego pagina web http://www.getaportal.com/portals/poker-160/juego_pagina_1.html jugar paginas internet casino gaming casino gaming http://www.freewebs.com/casino-398/casino-game-4.html http://www.freewebs.com/poker-603/giochi-8.html giochi internet giochi internet giochi giochi online giochi on line http://www.freewebs.com/poker-549/giochi-9.html

68.112.130.* 于 2007-07-16 04:33:27发表:

pokerparty encuentros poker http://www.getaportal.com/portals/casino-816/poker_1.html http://www.quizilla.com/users/ringtone-928/journal/570961/ madonna ringtone selena ringtone regola baccarat http://www.freewebs.com/poker-110/baccarat-4.html regole baccarat free keno games http://www.bloglines.com/blog/casino-198?id=28 video keno roulette on line casino roulette http://www.freewebs.com/casino-606/roulette-8.html

68.105.6.* 于 2007-07-16 03:59:41发表:

online slots internet slot machine http://www.freewebs.com/casino-674/slots-2.html free virgin mobile ringtone http://www.quizilla.com/users/ringtone-167/journal/570668/ free virgin mobile ringtone verizon ringtone ringtones http://www.quizilla.com/users/ringtone-90/journal/571104/ http://www.quizilla.com/users/ringtone-316/journal/572447/ ringtone free ringtone video poquer juega video poker online http://www.getaportal.com/portals/casino-585/video_poker_1.html

24.174.104.* 于 2007-07-16 03:40:35发表:

ringtones free sprint ringtones http://www.quizilla.com/users/ringtone-167/journal/570726/ regole baccarat http://www.freewebs.com/poker-82/baccarat-6.html regole baccarat http://www.getaportal.com/portals/casino-79/gamble_1.html wagering gambling portals http://www.getaportal.com/portals/poker-880/tragaperra_1.html tragamonedas tragaperras portales web casino internacional portales http://www.getaportal.com/portals/casino-633/casino_internacional_1.html casino internacional paginas internet

209.200.52.* 于 2007-07-16 02:09:20发表:

maquina tragaperras internet maquina tragaperras portales internet http://www.getaportal.com/portals/casino-241/maquinas_tragaperras_1.html http://www.freewebs.com/casino-606/casino-2.html casino in linea superiore casino on net world casino http://www.freewebs.com/casino-837/casino-2.html casinos in linea migliore http://www.freewebs.com/casino-834/casino-game-7.html casino gaming casino gioca casino italia http://www.freewebs.com/casino-834/casino-4.html casino in linea migliore

69.242.94.* 于 2007-07-16 02:05:37发表:

juego gratis portales http://www.getaportal.com/portals/casino-392/juego_gratis_1.html jugar gratis portal black eyed pea ringtones lil wayne ringtones http://www.quizilla.com/users/ringtone-695/journal/571076/ play poker online http://www.freewebs.com/poker-191/online-poker-4.html online poker game casino games casino gioca http://www.freewebs.com/casino-837/casino-game-5.html casino slot casinosvirtuales http://www.getaportal.com/portals/casino-328/casino_1.html

0.0.0.* 于 2007-07-16 02:01:00发表:

ringtone selena ringtone http://www.quizilla.com/users/ringtone-316/journal/572397/ http://www.freewebs.com/casino-985/casino-game-1.html casino games casino games ringtones ringtones http://www.quizilla.com/users/ringtone-696/journal/572834/ casinos descargas portal casinos descargas portales web http://www.getaportal.com/portals/poker-216/casino_descargas_1.html regole baccarat http://www.freewebs.com/poker-110/baccarat-8.html regola baccarat

24.22.180.* 于 2007-07-16 01:28:39发表:

cingular ringtone http://www.quizilla.com/users/ringtone-316/journal/572435/ mosquito ringtone carte gioco giochi carte online http://www.freewebs.com/poker-428/giochi-6.html selena ringtones http://www.quizilla.com/users/ringtone-582/journal/571070/ ringtones internet slot casino slots http://www.freewebs.com/casino-162/slots-3.html tragaperras portal internet tragaperras http://www.getaportal.com/portals/casino-633/tragaperra_1.html

85.92.136.* 于 2007-07-16 01:27:26发表:

london drug london drug http://www.tebidine.com/twm-enterprises/_disc1/00001303.htm frei spiel http://www.getaportal.com/portals/poker-918/spiel_2.html freispiel download free cingular ringtone http://www.quizilla.com/users/ringtone-869/journal/572301/ free ringtone play blackjack http://www.freewebs.com/casino-496/blackjack-3.html play blackjack ringtone http://www.quizilla.com/users/ringtone-24/journal/570789/ free sprint ringtone

212.0.126.* 于 2007-07-16 01:03:52发表:

free ringtones http://www.quizilla.com/users/ringtone-67/journal/572546/ free real ringtones download free ringtones nextel ringtone http://www.quizilla.com/users/ringtone-928/journal/571098/ casino virtual paginas web http://www.getaportal.com/portals/casino-816/casino_pagina_1.html casino virtual paginas internet http://www.getaportal.com/portals/poker-216/juego_interactivo_1.html juego interactivo paginas web jugar interactivo web http://www.freewebs.com/casino-182/casino-game-6.html casino games giochi casino

0.0.0.* 于 2007-07-16 00:18:02发表:

strategie crap regole crap http://www.freewebs.com/casino-978/craps-4.html maquinas tragaperras portal maquinas tragaperras portal http://www.getaportal.com/portals/poker-914/maquinas_tragaperras_1.html madonna ringtone ringtone http://www.quizilla.com/users/ringtone-135/journal/572478/ http://www.freewebs.com/casino-987/roulette-62.html free online roulette free roulette game bacara web juego bacara http://www.getaportal.com/portals/poker-113/baccarat_1.html

76.183.38.* 于 2007-07-16 00:06:19发表:

http://www.freewebs.com/poker-719/baccarat-3.html regole baccarat regole baccarat giochi giochi online http://www.freewebs.com/poker-979/giochi-2.html giochi giochi online lil wayne ringtone beatles ringtone http://www.quizilla.com/users/ringtone-869/journal/572374/ http://www.freewebs.com/casino-150/casino-game-1.html casinos games casino games free ringtones free ringtones http://www.quizilla.com/users/ringtone-90/journal/571042/

Linux操作系统内核模块与用户程序对比

共有 2222 条评论

频道文章

最新教程

随机推荐