[kernel] 转 sys创建目录和文件

#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kobject.h>
#include <linux/device.h>

static struct kobject *k_obj = NULL;
static struct kobject *k_obj_2 = NULL;

static char node_one_buf[20] = {0};

static ssize_t sysfs_demo_show_node_one(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{
pr_info("enter, node: %s\n", attr->attr.name);
return sprintf(buf, "%s: %s\n", attr->attr.name, node_one_buf);
}

static ssize_t sysfs_demo_store_node_one(struct kobject *kobj, struct kobj_attribute *attr, const char * buf, size_t n)
{
pr_info("enter, node: %s\n", attr->attr.name);

sprintf(node_one_buf, "%s", buf);

return n;
}

static struct kobj_attribute node_one_attribute =
__ATTR(node_one, S_IWUSR|S_IRUGO, sysfs_demo_show_node_one, sysfs_demo_store_node_one);

static ssize_t sysfs_demo_show_node_two(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{

return sprintf(buf, "%s\n", attr->attr.name);
}

static struct kobj_attribute node_two_attribute =
__ATTR(node_two, S_IWUSR|S_IRUGO, sysfs_demo_show_node_two, NULL);

static struct attribute *sysfs_demo_attributes[] = {
&node_one_attribute.attr,
&node_two_attribute.attr,
NULL
};

static const struct attribute_group sysfs_demo_attr_group = {
.attrs = sysfs_demo_attributes,
};

static char node_three_buf[20] = {0};

static ssize_t sysfs_demo_show_node_three(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{
pr_info("enter, node: %s\n", attr->attr.name);
return sprintf(buf, "%s: %s\n", attr->attr.name, node_three_buf);
}

static ssize_t sysfs_demo_store_node_three(struct kobject *kobj, struct kobj_attribute *attr, const char * buf, size_t n)
{
pr_info("enter, node: %s\n", attr->attr.name);

sprintf(node_three_buf, "%s", buf);

return n;
}

static struct kobj_attribute node_three_attribute =
__ATTR(node_three, S_IWUSR|S_IRUGO, sysfs_demo_show_node_three, sysfs_demo_store_node_three);

static ssize_t sysfs_demo_show_node_four(struct kobject *kobj, struct kobj_attribute *attr, char * buf)
{

return sprintf(buf, "%s\n", attr->attr.name);
}

static struct kobj_attribute node_four_attribute =
__ATTR(node_four, S_IWUSR|S_IRUGO, sysfs_demo_show_node_four, NULL);

static struct attribute *sysfs_demo2_attributes[] = {
&node_three_attribute.attr,
&node_four_attribute.attr,
NULL
};

static const struct attribute_group sysfs_demo2_attr_group = {
.attrs = sysfs_demo2_attributes,
};

static int __init sysfs_demo_init(void)
{
if ((k_obj = kobject_create_and_add("sysfs_demo", NULL)) == NULL ) {
pr_err("sysfs_demo sys node create error \n");
goto out;
}

if(sysfs_create_group(k_obj, &sysfs_demo_attr_group) ) {
pr_err("sysfs_create_group failed\n");
goto out2;
}

if ((k_obj_2 = kobject_create_and_add("sysfs_demo_2", k_obj)) == NULL ) {
pr_err("hwinfo sys node create error \n");
goto out3;
}

if(sysfs_create_group(k_obj_2, &sysfs_demo2_attr_group) ) {
pr_err("sysfs_create_group failed\n");
goto out4;
}

pr_info("enter.\n");
return 0;
out4:
kobject_put(k_obj_2);
out3:
sysfs_remove_group(k_obj, &sysfs_demo_attr_group);
out2:
kobject_put(k_obj);
out:
return -1;
}
module_init(sysfs_demo_init);

static void __exit sysfs_demo_exit(void)
{
pr_info("enter.\n");

if (k_obj) {
sysfs_remove_group(k_obj, &sysfs_demo_attr_group);
if (k_obj_2) {
sysfs_remove_group(k_obj_2, &sysfs_demo2_attr_group);
kobject_put(k_obj_2);
}
kobject_put(k_obj);
}

}
module_exit(sysfs_demo_exit);

MODULE_LICENSE("GPL");