Linux設備模型分析之kobject

內核版本：2.6.36

一、kobject應用舉例

Linux設備模型最基本的組成元素是kobject，我們先來看一個kobject的應用例子，該程序在Ubuntu 10.10, 2.6.32-38-generic-pae內核上調試通過。

 1#include <linux/device.h>  
 2#include <linux/module.h>  
 3#include <linux/kernel.h>  
 4#include <linux/init.h>  
 5#include <linux/string.h>  
 6#include <linux/sysfs.h>  
 7#include <linux/stat.h>  
 8  
 9MODULE_AUTHOR("haoyu");  
10MODULE_LICENSE("Dual BSD/GPL");  
11  
12void kobject_release(struct kobject *kobject);  
13ssize_t kobject_attr_show(struct kobject *kobject, struct attribute *attr,char *buf);  
14ssize_t kobject_attr_store(struct kobject *kobject,struct attribute *attr,const char *buf, size_t count);  
15  
16struct attribute kobject_attr1 = {  
17    .name = "kobject_attr1",  
18    .mode = S_IRWXUGO,  
19};  
20  
21struct attribute kobject_attr2 = {  
22    .name = "kobject_attr2",  
23    .mode = S_IRWXUGO,  
24};  
25  
26static struct attribute *kobject_def_attrs[] = {  
27    &kobject_attr1,  
28    &kobject_attr2,  
29    NULL,  
30};  
31  
32  
33struct sysfs_ops kobject_sysfs_ops =  
34{  
35    .show = kobject_attr_show,  
36    .store = kobject_attr_store,  
37};  
38  
39struct kobj_type ktype =  
40{  
41    .release = kobject_release,  
42    .sysfs_ops = &kobject_sysfs_ops,  
43    .default_attrs = kobject_def_attrs,  
44};  
45  
46void kobject_release(struct kobject *kobject)  
47{  
48    printk("kobject release.\n");  
49}  
50  
51ssize_t kobject_attr_show(struct kobject *kobject, struct attribute *attr,char *buf)  
52{  
53    printk("kobject attribute show.\n");  
54    if(strcmp(attr->name, "kobject_attr1") == 0)  
55        printk("kobject_attr1.\n");  
56    else if(strcmp(attr->name, "kobject_attr2") == 0)  
57        printk("kobject_attr2.\n");  
58    else  
59        printk("no this attribute.\n");  
60  
61    sprintf(buf,"%s\n",attr->name);  
62    return strlen(attr->name) + 2;  
63}  
64  
65ssize_t kobject_attr_store(struct kobject *kobject,struct attribute *attr,const char *buf, size_t count)  
66{  
67    printk("kobject attribute store.\n");  
68    if(strcmp(attr->name, "kobject_attr1") == 0)  
69        printk("kobject_attr1.\n");  
70    else if(strcmp(attr->name, "kobject_attr2") == 0)  
71        printk("kobject_attr2.\n");  
72    else  
73        printk("no this attribute.\n");  
74  
75    printk("buf = %s\n",buf);  
76    return count;  
77}  
78  
79struct kobject kobj;  
80static int kobject_test_init(void)  
81{  
82    printk("kboject test init.\n");  
83    kobject_init_and_add(&kobj,&ktype,NULL,"kobject_test");  
84    return 0;  
85}  
86  
87static void kobject_test_exit(void)  
88{  
89    printk("kobject test exit.\n");  
90    kobject_del(&kobj);  
91}  
92  
93module_init(kobject_test_init);  
94module_exit(kobject_test_exit);  
該模塊執行過程如下圖所示：