Linux内核 简化版kset-example.c解析
文章由LinuxBoy分享于2019-04-01 12:04:55
Linux内核 简化版kset-example.c解析
Linux内核 简化版kset-example.c解析
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- #include <linux/kobject.h>
- #include <linux/string.h>
- #include <linux/sysfs.h>
- #include <linux/slab.h>
- #include <linux/module.h>
- #include <linux/init.h>
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- struct foo_obj {
- struct kobject kobj;
- int foo;
- int baz;
- int bar;
- };
-
- #define to_foo_obj(x) container_of(x, struct foo_obj, kobj)
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-
- struct foo_attribute {
- struct attribute attr;
- ssize_t (*show)(struct foo_obj *foo, struct foo_attribute *attr, char *buf);
- ssize_t (*store)(struct foo_obj *foo, struct foo_attribute *attr, const char *buf, size_t count);
- };
- #define to_foo_attr(x) container_of(x, struct foo_attribute, attr)
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-
-
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- static ssize_t foo_attr_show(struct kobject *kobj,
- struct attribute *attr,
- char *buf)
- {
- struct foo_attribute *attribute;
- struct foo_obj *foo;
-
- attribute = to_foo_attr(attr);
- foo = to_foo_obj(kobj);
-
- if (!attribute->show)
- return -EIO;
-
- return attribute->show(foo, attribute, buf);
- }
-
-
-
-
- static ssize_t foo_attr_store(struct kobject *kobj,
- struct attribute *attr,
- const char *buf, size_t len)
- {
- struct foo_attribute *attribute;
- struct foo_obj *foo;
-
- attribute = to_foo_attr(attr);
- foo = to_foo_obj(kobj);
-
- if (!attribute->store)
- return -EIO;
-
- return attribute->store(foo, attribute, buf, len);
- }
-
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-
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- static const struct sysfs_ops foo_sysfs_ops = {
- .show = foo_attr_show,
- .store = foo_attr_store,
- };
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- static void foo_release(struct kobject *kobj)
- {
- struct foo_obj *foo;
-
- foo = to_foo_obj(kobj);
- kfree(foo);
- }
-
-
-
-
- static ssize_t foo_show(struct foo_obj *foo_obj, struct foo_attribute *attr,
- char *buf)
- {
- return sprintf(buf, "%d\n", foo_obj->foo);
- }
-
-
-
-
- static ssize_t foo_store(struct foo_obj *foo_obj, struct foo_attribute *attr,
- const char *buf, size_t count)
- {
- sscanf(buf, "%du", &foo_obj->foo);
- return count;
- }
-
- static struct foo_attribute foo_attribute =
- __ATTR(foo, 0666, foo_show, foo_store);
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-
-
-
- static struct attribute *foo_default_attrs[] = {
- &foo_attribute.attr,
- NULL,
- };
-
-
-
-
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- static struct kobj_type foo_ktype = {
- .sysfs_ops = &foo_sysfs_ops,
- .release = foo_release,
- .default_attrs = foo_default_attrs,
- };
-
- static struct kset *example_kset;
- static struct foo_obj *foo_obj;
-
- static struct foo_obj *create_foo_obj(const char *name)
- {
- struct foo_obj *foo;
- int retval;
-
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- foo = kzalloc(sizeof(*foo), GFP_KERNEL);
- if (!foo)
- return NULL;
-
- foo->kobj.kset = example_kset;
-
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- retval = kobject_init_and_add(&foo->kobj, &foo_ktype, NULL, "%s", name);
- if (retval) {
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- kobject_put(&foo->kobj);
- return NULL;
- }
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- kobject_uevent(&foo->kobj, KOBJ_ADD);
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- return foo;
- }
-
- static void destroy_foo_obj(struct foo_obj *foo)
- {
-
- kobject_put(&foo->kobj);
- }
-
- static int __init example_init(void)
- {
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- example_kset = kset_create_and_add("kset_example", NULL, kernel_kobj);
- if (!example_kset)
- return -ENOMEM;
-
- foo_obj = create_foo_obj("foo");
- if (!foo_obj)
- goto foo_error;
-
- return 0;
-
- foo_error:
- return -EINVAL;
- }
-
- static void __exit example_exit(void)
- {
- destroy_foo_obj(foo_obj);
- kset_unregister(example_kset);
- }
-
- module_init(example_init);
- module_exit(example_exit);
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("lewiyon <lewiyon@hotmail.com>");
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