Linux内核模块编程指南2.6：免费开源

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《Linux内核模块编程指南2.6》是由Peter Jay Salzman、Michael Burian和Ori Pomerantz共同编著的一本开源书籍，于2001年由Salzman撰写，后续更新至2.6.4版本。该书在2007年5月18日发布，遵循开放源代码许可证（Open Software License, OSL）v1.1，允许用户在不侵犯版权的前提下自由复制、修改或分发。本书的目标是提供一个详细的指南，帮助读者理解和学习如何编写Linux内核模块，即可以直接加载到Linux内核中的可动态加载的代码段。它涵盖了从模块的基本结构、编译过程、初始化和卸载机制，到内存管理、系统调用接口、信号处理和错误处理等核心概念。作者鼓励广泛地分享此书，无论是个人学习还是商业用途，只要保留原始版权声明，并遵守OSL协议的规定即可，无需事先得到作者的特别许可。对于衍生作品和翻译，必须同样按照OSL授权，并确保原始版权信息不受改动。如果读者在书中添加了新的内容，也必须将其置于相同的开放许可之下。这是一本实用且自由的资源，适合Linux开发者深入理解并实践内核模块开发技术。通过阅读和实践这本书，读者能够提升自己的Linux内核编程技能，参与到开源社区的贡献中去。

printk(KERN_INFO "Hello, world 4\n");

return 0;

}

static void __exit cleanup_hello_4(void)

{

printk(KERN_INFO "Goodbye, world 4\n");

}

module_init(init_hello_4);

module_exit(cleanup_hello_4);

* You can use strings, like this:

* Get rid of taint message by declaring code as GPL.

MODULE_LICENSE("GPL");

* Or with defines, like this:

MODULE_AUTHOR(DRIVER_AUTHOR); /* Who wrote this module? */

MODULE_DESCRIPTION(DRIVER_DESC); /* What does this module do */

* This module uses /dev/testdevice. The MODULE_SUPPORTED_DEVICE macro might

* be used in the future to help automatic configuration of modules, but is

* currently unused other than for documentation purposes.

MODULE_SUPPORTED_DEVICE("testdevice");

2.6. Passing Command Line Arguments to a Module

Modules can take command line arguments, but not with the argc/argv you might be used to.

To allow arguments to be passed to your module, declare the variables that will take the values of the

command line arguments as global and then use the module_param() macro, (defined in

linux/moduleparam.h) to set the mechanism up. At runtime, insmod will fill the variables with any

command line arguments that are given, like ./insmod mymodule.ko myvariable=5. The variable

declarations and macros should be placed at the beginning of the module for clarity. The example code should

clear up my admittedly lousy explanation.

The module_param() macro takes 3 arguments: the name of the variable, its type and permissions for the

corresponding file in sysfs. Integer types can be signed as usual or unsigned. If you'd like to use arrays of

integers or strings see module_param_array() and module_param_string().

int myint = 3;

module_param(myint, int, 0);

Arrays are supported too, but things are a bit different now than they were in the 2.4. days. To keep track of

the number of parameters you need to pass a pointer to a count variable as third parameter. At your option,

you could also ignore the count and pass NULL instead. We show both possibilities here:

The Linux Kernel Module Programming Guide

Chapter 2. Hello World 11

int myintarray[2];

module_param_array(myintarray, int, NULL, 0); /* not interested in count */

int myshortarray[4];

int count;

module_parm_array(myshortarray, short, , 0); /* put count into "count" variable */

A good use for this is to have the module variable's default values set, like an port or IO address. If the

variables contain the default values, then perform autodetection (explained elsewhere). Otherwise, keep the

current value. This will be made clear later on.

Lastly, there's a macro function, MODULE_PARM_DESC(), that is used to document arguments that the

module can take. It takes two parameters: a variable name and a free form string describing that variable.

Example 2−7. hello−5.c

* hello−5.c − Demonstrates command line argument passing to a module.

#include <linux/module.h>

#include <linux/moduleparam.h>

#include <linux/kernel.h>

#include <linux/init.h>

#include <linux/stat.h>

MODULE_LICENSE("GPL");

MODULE_AUTHOR("Peter Jay Salzman");

static short int myshort = 1;

static int myint = 420;

static long int mylong = 9999;

static char *mystring = "blah";

static int myintArray[2] = { −1, −1 };

static int arr_argc = 0;

* module_param(foo, int, 0000)

* The first param is the parameters name

* The second param is it's data type

* The final argument is the permissions bits,

* for exposing parameters in sysfs (if non−zero) at a later stage.

module_param(myshort, short, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);

MODULE_PARM_DESC(myshort, "A short integer");

module_param(myint, int, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);

MODULE_PARM_DESC(myint, "An integer");

module_param(mylong, long, S_IRUSR);

MODULE_PARM_DESC(mylong, "A long integer");

module_param(mystring, charp, 0000);

MODULE_PARM_DESC(mystring, "A character string");

* module_param_array(name, type, num, perm);

* The first param is the parameter's (in this case the array's) name

* The second param is the data type of the elements of the array

* The third argument is a pointer to the variable that will store the number

* of elements of the array initialized by the user at module loading time

* The fourth argument is the permission bits

The Linux Kernel Module Programming Guide

Chapter 2. Hello World 12

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Linux内核模块编程指南2.6：免费开源

The Linux Kernel Module Programming Guide 2.6.pdf

The Linux Kernel Module Programming Guide 2.6 中文版

The Linux Kernel Module Programming Guide 2.6 pdf版

The Linux Kernel Module Programming Guide 2.6 例程

The Linux Kernel Module Programming Guide 2.6中文版

The Linux Kernel Module Programming Guide 2.6中英文版本

The Linux Kernel Module Programming Guide 2.6英文doc版

The Linux Kernel Module Programming Guide 2.6 中文版+英文版

The Linux Kernel Module Programming Guide 2.6 中英文對照版

The Linux Kernel Module Programming Guide.pdf

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