kobject.h revision 5c03c7ab886859eb195440dbb6ccb8c30c4e84cc 
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) 2006-2007 Greg Kroah-Hartman <greg@kroah.com>
7 * Copyright (c) 2006-2007 Novell Inc.
8 *
9 * This file is released under the GPLv2.
10 *
11 *
12 * Please read Documentation/kobject.txt before using the kobject
13 * interface, ESPECIALLY the parts about reference counts and object
14 * destructors.
15 */
16
17#ifndef _KOBJECT_H_
18#define _KOBJECT_H_
19
20#ifdef __KERNEL__
21
22#include <linux/types.h>
23#include <linux/list.h>
24#include <linux/sysfs.h>
25#include <linux/compiler.h>
26#include <linux/spinlock.h>
27#include <linux/kref.h>
28#include <linux/kernel.h>
29#include <linux/wait.h>
30#include <asm/atomic.h>
31
32#define KOBJ_NAME_LEN			20
33#define UEVENT_HELPER_PATH_LEN		256
34#define UEVENT_NUM_ENVP			32	/* number of env pointers */
35#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */
36
37/* path to the userspace helper executed on an event */
38extern char uevent_helper[];
39
40/* counter to tag the uevent, read only except for the kobject core */
41extern u64 uevent_seqnum;
42
43/*
44 * The actions here must match the index to the string array
45 * in lib/kobject_uevent.c
46 *
47 * Do not add new actions here without checking with the driver-core
48 * maintainers. Action strings are not meant to express subsystem
49 * or device specific properties. In most cases you want to send a
50 * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
51 * specific variables added to the event environment.
52 */
53enum kobject_action {
54	KOBJ_ADD,
55	KOBJ_REMOVE,
56	KOBJ_CHANGE,
57	KOBJ_MOVE,
58	KOBJ_ONLINE,
59	KOBJ_OFFLINE,
60	KOBJ_MAX
61};
62
63struct kobject {
64	const char		* k_name;
65	struct kref		kref;
66	struct list_head	entry;
67	struct kobject		* parent;
68	struct kset		* kset;
69	struct kobj_type	* ktype;
70	struct sysfs_dirent	* sd;
71};
72
73extern int kobject_set_name(struct kobject *, const char *, ...)
74	__attribute__((format(printf,2,3)));
75
76static inline const char * kobject_name(const struct kobject * kobj)
77{
78	return kobj->k_name;
79}
80
81extern void kobject_init(struct kobject *);
82extern void kobject_init_ng(struct kobject *kobj, struct kobj_type *ktype);
83extern int __must_check kobject_add(struct kobject *);
84extern int __must_check kobject_add_ng(struct kobject *kobj,
85				       struct kobject *parent,
86				       const char *fmt, ...);
87extern int __must_check kobject_init_and_add(struct kobject *kobj,
88					     struct kobj_type *ktype,
89					     struct kobject *parent,
90					     const char *fmt, ...);
91
92extern void kobject_del(struct kobject *);
93
94extern struct kobject * __must_check kobject_create(void);
95extern struct kobject * __must_check kobject_create_and_add(const char *name,
96						struct kobject *parent);
97
98extern int __must_check kobject_rename(struct kobject *, const char *new_name);
99extern int __must_check kobject_move(struct kobject *, struct kobject *);
100
101extern int __must_check kobject_register(struct kobject *);
102extern void kobject_unregister(struct kobject *);
103
104extern struct kobject * kobject_get(struct kobject *);
105extern void kobject_put(struct kobject *);
106
107extern char * kobject_get_path(struct kobject *, gfp_t);
108
109struct kobj_type {
110	void (*release)(struct kobject *);
111	struct sysfs_ops	* sysfs_ops;
112	struct attribute	** default_attrs;
113};
114
115struct kobj_uevent_env {
116	char *envp[UEVENT_NUM_ENVP];
117	int envp_idx;
118	char buf[UEVENT_BUFFER_SIZE];
119	int buflen;
120};
121
122struct kset_uevent_ops {
123	int (*filter)(struct kset *kset, struct kobject *kobj);
124	const char *(*name)(struct kset *kset, struct kobject *kobj);
125	int (*uevent)(struct kset *kset, struct kobject *kobj,
126		      struct kobj_uevent_env *env);
127};
128
129struct kobj_attribute {
130	struct attribute attr;
131	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
132			char *buf);
133	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
134			 const char *buf, size_t count);
135};
136
137extern struct sysfs_ops kobj_sysfs_ops;
138
139/**
140 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
141 *
142 * A kset defines a group of kobjects.  They can be individually
143 * different "types" but overall these kobjects all want to be grouped
144 * together and operated on in the same manner.  ksets are used to
145 * define the attribute callbacks and other common events that happen to
146 * a kobject.
147 *
148 * @list: the list of all kobjects for this kset
149 * @list_lock: a lock for iterating over the kobjects
150 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
151 * @uevent_ops: the set of uevent operations for this kset.  These are
152 * called whenever a kobject has something happen to it so that the kset
153 * can add new environment variables, or filter out the uevents if so
154 * desired.
155 */
156struct kset {
157	struct list_head	list;
158	spinlock_t		list_lock;
159	struct kobject		kobj;
160	struct kset_uevent_ops	*uevent_ops;
161};
162
163extern void kset_init(struct kset * k);
164extern int __must_check kset_add(struct kset * k);
165extern int __must_check kset_register(struct kset * k);
166extern void kset_unregister(struct kset * k);
167extern struct kset * __must_check kset_create_and_add(const char *name,
168						struct kset_uevent_ops *u,
169						struct kobject *parent_kobj);
170
171static inline struct kset * to_kset(struct kobject * kobj)
172{
173	return kobj ? container_of(kobj,struct kset,kobj) : NULL;
174}
175
176static inline struct kset * kset_get(struct kset * k)
177{
178	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
179}
180
181static inline void kset_put(struct kset * k)
182{
183	kobject_put(&k->kobj);
184}
185
186static inline struct kobj_type *get_ktype(struct kobject *kobj)
187{
188	return kobj->ktype;
189}
190
191extern struct kobject * kset_find_obj(struct kset *, const char *);
192
193
194/*
195 * Use this when initializing an embedded kset with no other
196 * fields to initialize.
197 */
198#define set_kset_name(str)	.kset = { .kobj = { .k_name = str } }
199
200
201/* The global /sys/kernel/ kset for people to chain off of */
202extern struct kset *kernel_kset;
203/* The global /sys/hypervisor/ kobject for people to chain off of */
204extern struct kobject *hypervisor_kobj;
205/* The global /sys/power/ kset for people to chain off of */
206extern struct kset *power_kset;
207/* The global /sys/firmware/ kobject for people to chain off of */
208extern struct kobject *firmware_kobj;
209
210extern int __must_check subsystem_register(struct kset *);
211extern void subsystem_unregister(struct kset *);
212
213#if defined(CONFIG_HOTPLUG)
214int kobject_uevent(struct kobject *kobj, enum kobject_action action);
215int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
216			char *envp[]);
217
218int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
219	__attribute__((format (printf, 2, 3)));
220
221int kobject_action_type(const char *buf, size_t count,
222			enum kobject_action *type);
223#else
224static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
225{ return 0; }
226static inline int kobject_uevent_env(struct kobject *kobj,
227				      enum kobject_action action,
228				      char *envp[])
229{ return 0; }
230
231static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
232{ return 0; }
233
234static inline int kobject_action_type(const char *buf, size_t count,
235			enum kobject_action *type)
236{ return -EINVAL; }
237#endif
238
239#endif /* __KERNEL__ */
240#endif /* _KOBJECT_H_ */
241