kobject.h revision aab0de245150c09e61c30962feb16aacde508dc3 
1/*
2 * kobject.h - generic kernel object infrastructure.
3 *
4 * Copyright (c) 2002-2003 Patrick Mochel
5 * Copyright (c) 2002-2003 Open Source Development Labs
6 * Copyright (c) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
7 * Copyright (c) 2006-2008 Novell Inc.
8 *
9 * This file is released under the GPLv2.
10 *
11 * Please read Documentation/kobject.txt before using the kobject
12 * interface, ESPECIALLY the parts about reference counts and object
13 * destructors.
14 */
15
16#ifndef _KOBJECT_H_
17#define _KOBJECT_H_
18
19#include <linux/types.h>
20#include <linux/list.h>
21#include <linux/sysfs.h>
22#include <linux/compiler.h>
23#include <linux/spinlock.h>
24#include <linux/kref.h>
25#include <linux/kernel.h>
26#include <linux/wait.h>
27#include <asm/atomic.h>
28
29#define UEVENT_HELPER_PATH_LEN		256
30#define UEVENT_NUM_ENVP			32	/* number of env pointers */
31#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */
32
33/* path to the userspace helper executed on an event */
34extern char uevent_helper[];
35
36/* counter to tag the uevent, read only except for the kobject core */
37extern u64 uevent_seqnum;
38
39/*
40 * The actions here must match the index to the string array
41 * in lib/kobject_uevent.c
42 *
43 * Do not add new actions here without checking with the driver-core
44 * maintainers. Action strings are not meant to express subsystem
45 * or device specific properties. In most cases you want to send a
46 * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
47 * specific variables added to the event environment.
48 */
49enum kobject_action {
50	KOBJ_ADD,
51	KOBJ_REMOVE,
52	KOBJ_CHANGE,
53	KOBJ_MOVE,
54	KOBJ_ONLINE,
55	KOBJ_OFFLINE,
56	KOBJ_MAX
57};
58
59struct kobject {
60	const char		*name;
61	struct kref		kref;
62	struct list_head	entry;
63	struct kobject		*parent;
64	struct kset		*kset;
65	struct kobj_type	*ktype;
66	struct sysfs_dirent	*sd;
67	unsigned int state_initialized:1;
68	unsigned int state_in_sysfs:1;
69	unsigned int state_add_uevent_sent:1;
70	unsigned int state_remove_uevent_sent:1;
71};
72
73extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
74			    __attribute__((format(printf, 2, 3)));
75
76static inline const char *kobject_name(const struct kobject *kobj)
77{
78	return kobj->name;
79}
80
81extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
82extern int __must_check kobject_add(struct kobject *kobj,
83				    struct kobject *parent,
84				    const char *fmt, ...);
85extern int __must_check kobject_init_and_add(struct kobject *kobj,
86					     struct kobj_type *ktype,
87					     struct kobject *parent,
88					     const char *fmt, ...);
89
90extern void kobject_del(struct kobject *kobj);
91
92extern struct kobject * __must_check kobject_create(void);
93extern struct kobject * __must_check kobject_create_and_add(const char *name,
94						struct kobject *parent);
95
96extern int __must_check kobject_rename(struct kobject *, const char *new_name);
97extern int __must_check kobject_move(struct kobject *, struct kobject *);
98
99extern struct kobject *kobject_get(struct kobject *kobj);
100extern void kobject_put(struct kobject *kobj);
101
102extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
103
104struct kobj_type {
105	void (*release)(struct kobject *kobj);
106	struct sysfs_ops *sysfs_ops;
107	struct attribute **default_attrs;
108};
109
110struct kobj_uevent_env {
111	char *envp[UEVENT_NUM_ENVP];
112	int envp_idx;
113	char buf[UEVENT_BUFFER_SIZE];
114	int buflen;
115};
116
117struct kset_uevent_ops {
118	int (*filter)(struct kset *kset, struct kobject *kobj);
119	const char *(*name)(struct kset *kset, struct kobject *kobj);
120	int (*uevent)(struct kset *kset, struct kobject *kobj,
121		      struct kobj_uevent_env *env);
122};
123
124struct kobj_attribute {
125	struct attribute attr;
126	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
127			char *buf);
128	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
129			 const char *buf, size_t count);
130};
131
132extern struct sysfs_ops kobj_sysfs_ops;
133
134/**
135 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
136 *
137 * A kset defines a group of kobjects.  They can be individually
138 * different "types" but overall these kobjects all want to be grouped
139 * together and operated on in the same manner.  ksets are used to
140 * define the attribute callbacks and other common events that happen to
141 * a kobject.
142 *
143 * @list: the list of all kobjects for this kset
144 * @list_lock: a lock for iterating over the kobjects
145 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
146 * @uevent_ops: the set of uevent operations for this kset.  These are
147 * called whenever a kobject has something happen to it so that the kset
148 * can add new environment variables, or filter out the uevents if so
149 * desired.
150 */
151struct kset {
152	struct list_head list;
153	spinlock_t list_lock;
154	struct kobject kobj;
155	struct kset_uevent_ops *uevent_ops;
156};
157
158extern void kset_init(struct kset *kset);
159extern int __must_check kset_register(struct kset *kset);
160extern void kset_unregister(struct kset *kset);
161extern struct kset * __must_check kset_create_and_add(const char *name,
162						struct kset_uevent_ops *u,
163						struct kobject *parent_kobj);
164
165static inline struct kset *to_kset(struct kobject *kobj)
166{
167	return kobj ? container_of(kobj, struct kset, kobj) : NULL;
168}
169
170static inline struct kset *kset_get(struct kset *k)
171{
172	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
173}
174
175static inline void kset_put(struct kset *k)
176{
177	kobject_put(&k->kobj);
178}
179
180static inline struct kobj_type *get_ktype(struct kobject *kobj)
181{
182	return kobj->ktype;
183}
184
185extern struct kobject *kset_find_obj(struct kset *, const char *);
186
187/* The global /sys/kernel/ kobject for people to chain off of */
188extern struct kobject *kernel_kobj;
189/* The global /sys/hypervisor/ kobject for people to chain off of */
190extern struct kobject *hypervisor_kobj;
191/* The global /sys/power/ kobject for people to chain off of */
192extern struct kobject *power_kobj;
193/* The global /sys/firmware/ kobject for people to chain off of */
194extern struct kobject *firmware_kobj;
195
196#if defined(CONFIG_HOTPLUG)
197int kobject_uevent(struct kobject *kobj, enum kobject_action action);
198int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
199			char *envp[]);
200
201int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
202	__attribute__((format (printf, 2, 3)));
203
204int kobject_action_type(const char *buf, size_t count,
205			enum kobject_action *type);
206#else
207static inline int kobject_uevent(struct kobject *kobj,
208				 enum kobject_action action)
209{ return 0; }
210static inline int kobject_uevent_env(struct kobject *kobj,
211				      enum kobject_action action,
212				      char *envp[])
213{ return 0; }
214
215static inline int add_uevent_var(struct kobj_uevent_env *env,
216				 const char *format, ...)
217{ return 0; }
218
219static inline int kobject_action_type(const char *buf, size_t count,
220				      enum kobject_action *type)
221{ return -EINVAL; }
222#endif
223
224#endif /* _KOBJECT_H_ */
225