Ubuntu 10.04 加载/卸载 自定义 module

hello.c

01	// Defining __KERNEL__ and MODULE allows us to access kernel-level code not usually available to userspace programs.

02	#undef __KERNEL__

03	#define __KERNEL__

04

05	#undef MODULE

06	#define MODULE

07

08	// Linux Kernel/LKM headers: module.h is needed by all modules and kernel.h is needed for KERN_INFO.

09	#include <linux/module.h>    // included for all kernel modules

10	#include <linux/kernel.h>    // included for KERN_INFO

11	#include <linux/init.h>        // included for __init and __exit macros

12

13	static int __init hello_init(void)

14

{

15	printk(KERN_INFO "Hello world!\n");

16	return 0;    // Non-zero return means that the module couldn't be loaded.

17

}

18

19	static void __exit hello_cleanup(void)

20

{

21	printk(KERN_INFO "Cleaning up module.\n");

22

}

23

24	module_init(hello_init);

25	module_exit(hello_cleanup);

Makefile

1	obj-m := hello.o

2	KDIR := /lib/modules/$(shell uname -r)/build

3	PWD := $(shell pwd)

4

5

all:

6	$(MAKE) -C $(KDIR) M=$(PWD) modules

7

8

clean:

9	$(MAKE) -C $(KDIR) M=$(PWD) clean

执行命令: make

你也许会得到如下错误：

01	In file included from /usr/src/linux-headers-2.6.32-38-generic/include/linux/list.h:6,

02	from /usr/src/linux-headers-2.6.32-38-generic/include/linux/module.h:9,

03	from hello_module.c:1:

04	/usr/src/linux-headers-2.6.32-38-generic/include/linux/prefetch.h:14:27: error: asm/processor.h: No such file or directory

05	/usr/src/linux-headers-2.6.32-38-generic/include/linux/prefetch.h:15:23: error: asm/cache.h: No such file or directory

06	In file included from /usr/src/linux-headers-2.6.32-38-generic/include/linux/module.h:9,

07	from hello_module.c:1:

08	/usr/src/linux-headers-2.6.32-38-generic/include/linux/list.h:7:24: error: asm/system.h: No such file or directory

09	In file included from /usr/src/linux-headers-2.6.32-38-generic/include/linux/kernel.h:11,

10	from /usr/src/linux-headers-2.6.32-38-

11

12

......

你需要做如下操作：

Install and prepare module-assistant.

1

$ sudo -i

2	$ apt-get install module-assistant

3	$ m-a prepare

4

5

6	$  sudo apt-get install build-essential linux-headers-$(uname -r)

然后再次输入命令：make

1

$ make

2	make -C /lib/modules/2.6.32-38-generic/build M=/home/jerikc/studydir/linux/module modules

3	make[1]: Entering directory `/usr/src/linux-headers-2.6.32-38-generic'

4	CC [M]  /home/jerikc/studydir/linux/module/hello.o

5	Building modules, stage 2.

6	MODPOST 1 modules

7	CC      /home/jerikc/studydir/linux/module/hello.mod.o

8	LD [M]  /home/jerikc/studydir/linux/module/hello.ko

9	make[1]: Leaving directory `/usr/src/linux-headers-2.6.32-38-generic'

OK，成功得到hello.ko，下面进行测试：

加载module：

1	<span></span>$ sudo insmod hello.ko

验证：

1	$ tail /var/log/syslog

1	Aug 25 12:29:07 ubuntu dhclient: DHCPREQUEST of 192.168.10.129 on eth0 to 192.168.10.254 port 67

2	Aug 25 12:29:07 ubuntu dhclient: DHCPACK of 192.168.10.129 from 192.168.10.254

3	Aug 25 12:29:07 ubuntu dhclient: bound to 192.168.10.129 -- renewal in 865 seconds.

4	Aug 25 12:33:32 ubuntu kernel: [ 1886.549673] Hello world!

或者使用lsmod查看module信息：

1

$ lsmod

2	Module                  Size  Used by

3	hello                    596  0

4	...                      ...  ...

卸载module：

1	$ sudo rmmod hello

1	$ tail /var/log/syslog

view source

print ?

1	Aug 25 12:43:32 ubuntu dhclient: DHCPREQUEST of 192.168.10.129 on eth0 to 192.168.10.254 port 67

2	Aug 25 12:43:32 ubuntu dhclient: DHCPACK of 192.168.10.129 from 192.168.10.254

3	Aug 25 12:43:32 ubuntu dhclient: bound to 192.168.10.129 -- renewal in 702 seconds.

4	Aug 25 12:51:07 ubuntu kernel: [ 2939.379275] Cleaning up module.

实验完毕!