linux内核事件通知,Linux内核基础--事件通知链(notifier chain)

迈不过友情╰ 2023-01-19 15:59 273阅读 0赞

1.4. 简单一例：

通过上面所述，notifier\_chain机制只能在内核个子系统间使用，因此，这里使用3个模块：test\_notifier\_chain\_0、test\_notifier\_chain\_1、test\_notifier\_chain\_2；当 test\_notifier\_chain\_2通过module\_init初始化模块时发出事件TESTCHAIN\_2\_INIT；然后 test\_notifier\_chain\_1作出相应的处理：打印 test\_notifier\_chain\_2正在初始化。

/\* test\_chain\_0.c ：0. 申明一个通知链；1. 向内核注册通知链；2. 定义事件； 3. 导出符号，因而必需最后退出\*/

\#include

\#include /\* printk() \*/

\#include /\* everything() \*/

\#define TESTCHAIN\_INIT 0x52U

static RAW\_NOTIFIER\_HEAD(test\_chain);

/\* define our own notifier\_call\_chain \*/

static int call\_test\_notifiers(unsigned long val, void \*v)

return raw\_notifier\_call\_chain(&test\_chain, val, v);

EXPORT\_SYMBOL(call\_test\_notifiers);

/\* define our own notifier\_chain\_register func \*/

static int register\_test\_notifier(struct notifier\_block \*nb)

int err;

err = raw\_notifier\_chain\_register(&test\_chain, nb);

if(err)

goto out;

out:

return err;

EXPORT\_SYMBOL(register\_test\_notifier);

static int \_\_init test\_chain\_0\_init(void)

printk(KERN\_DEBUG "I'm in test\_chain\_0\\n");

return 0;

static void \_\_exit test\_chain\_0\_exit(void)

printk(KERN\_DEBUG "Goodbye to test\_chain\_0\\n");

// call\_test\_notifiers(TESTCHAIN\_EXIT, (int \*)NULL);

MODULE\_LICENSE("GPL v2");

MODULE\_AUTHOR("fishOnFly");

module\_init(test\_chain\_0\_init);

module\_exit(test\_chain\_0\_exit);

/\* test\_chain\_1.c ：1. 定义回调函数；2. 定义notifier\_block；3. 向chain\_0注册notifier\_block；\*/

\#include

\#include /\* printk() \*/

\#include /\* everything() \*/

extern int register\_test\_notifier(struct notifier\_block \*nb);

\#define TESTCHAIN\_INIT 0x52U

/\* realize the notifier\_call func \*/

int test\_init\_event(struct notifier\_block \*nb, unsigned long event,

void \*v)

switch(event)\{

case TESTCHAIN\_INIT:

printk(KERN\_DEBUG "I got the chain event: test\_chain\_2 is on the way of init\\n");

break;

default:

break;

return NOTIFY\_DONE;

/\* define a notifier\_block \*/

static struct notifier\_block test\_init\_notifier = \{

.notifier\_call = test\_init\_event,

\};

static int \_\_init test\_chain\_1\_init(void)

printk(KERN\_DEBUG "I'm in test\_chain\_1\\n");

return 0;

static void \_\_exit test\_chain\_1\_exit(void)

printk(KERN\_DEBUG "Goodbye to test\_clain\_l\\n");

MODULE\_LICENSE("GPL");

MODULE\_AUTHOR("fishOnFly");

module\_init(test\_chain\_1\_init);

module\_exit(test\_chain\_1\_exit);

/\* test\_chain\_2.c：发出通知链事件\*/

\#include

\#include /\* printk() \*/

\#include /\* everything() \*/

extern int call\_test\_notifiers(unsigned long val, void \*v);

\#define TESTCHAIN\_INIT 0x52U

static int \_\_init test\_chain\_2\_init(void)

printk(KERN\_DEBUG "I'm in test\_chain\_2\\n");

call\_test\_notifiers(TESTCHAIN\_INIT, "no\_use");

return 0;

static void \_\_exit test\_chain\_2\_exit(void)

printk(KERN\_DEBUG "Goodbye to test\_chain\_2\\n");

MODULE\_LICENSE("GPL v2");

MODULE\_AUTHOR("fishOnFly");

module\_init(test\_chain\_2\_init);

module\_exit(test\_chain\_2\_exit);

\# Makefile

\# Comment/uncomment the following line to disable/enable debugging

\# DEBUG = y

\# Add your debugging flag (or not) to CFLAGS

ifeq ($(DEBUG),y)

DEBFLAGS = -O -g -DSCULL\_DEBUG \# "-O" is needed to expand inlines

else

DEBFLAGS = -O2

endif

ifneq ($(KERNELRELEASE),)

\# call from kernel build system

obj-m := test\_chain\_0.o test\_chain\_1.o test\_chain\_2.o

else

KERNELDIR ?= /lib/modules/$(shell uname -r)/build

PWD := $(shell pwd)

modules:

$(MAKE) -C $(KERNELDIR) M=$(PWD) modules

endif

clean:

rm -rf \*.o \*~ core .depend .\*.cmd \*.ko \*.mod.c .tmp\_versions

depend .depend dep:

$(CC) $(CFLAGS) -M \*.c > .depend

ifeq (.depend,$(wildcard .depend))

include .depend

endif

\[wang2@iwooing: notifier\_chian\]$ sudo insmod./test\_chain\_0.ko

\[wang2@iwooing: notifier\_chian\]$ sudo insmod./test\_chain\_1.ko

\[wang2@iwooing: notifier\_chian\]$ sudo insmod./test\_chain\_2.ko

\[wang2@iwooing: notifier\_chian\]$ dmesg

\[ 5950.112649\] I'm in test\_chain\_0

\[ 5956.766610\] I'm in test\_chain\_1

\[ 5962.570003\] I'm in test\_chain\_2

\[ 5962.570008\] I got the chain event: test\_chain\_2 is on the way of init

\[ 6464.042975\] Goodbye to test\_chain\_2

\[ 6466.368030\] Goodbye to test\_clain\_l

\[ 6468.371479\] Goodbye to test\_chain\_0![0b1331709591d260c1c78e86d0c51c18.png][]

[0b1331709591d260c1c78e86d0c51c18.png]: /images/20221021/947b6285e5da48dda4d448ab5b9652ad.png

linux内核事件通知,Linux内核基础--事件通知链(notifier chain)

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