kobject.h revision 12e339ac6e31a34fe42396aec8fb1c0b43caf61e 
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 *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 *);
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 void kobject_unregister(struct kobject *);
100
101extern struct kobject * kobject_get(struct kobject *);
102extern void kobject_put(struct kobject *);
103
104extern char * kobject_get_path(struct kobject *, gfp_t);
105
106struct kobj_type {
107	void (*release)(struct kobject *);
108	struct sysfs_ops	* sysfs_ops;
109	struct attribute	** default_attrs;
110};
111
112struct kobj_uevent_env {
113	char *envp[UEVENT_NUM_ENVP];
114	int envp_idx;
115	char buf[UEVENT_BUFFER_SIZE];
116	int buflen;
117};
118
119struct kset_uevent_ops {
120	int (*filter)(struct kset *kset, struct kobject *kobj);
121	const char *(*name)(struct kset *kset, struct kobject *kobj);
122	int (*uevent)(struct kset *kset, struct kobject *kobj,
123		      struct kobj_uevent_env *env);
124};
125
126struct kobj_attribute {
127	struct attribute attr;
128	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
129			char *buf);
130	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
131			 const char *buf, size_t count);
132};
133
134extern struct sysfs_ops kobj_sysfs_ops;
135
136/**
137 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
138 *
139 * A kset defines a group of kobjects.  They can be individually
140 * different "types" but overall these kobjects all want to be grouped
141 * together and operated on in the same manner.  ksets are used to
142 * define the attribute callbacks and other common events that happen to
143 * a kobject.
144 *
145 * @list: the list of all kobjects for this kset
146 * @list_lock: a lock for iterating over the kobjects
147 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
148 * @uevent_ops: the set of uevent operations for this kset.  These are
149 * called whenever a kobject has something happen to it so that the kset
150 * can add new environment variables, or filter out the uevents if so
151 * desired.
152 */
153struct kset {
154	struct list_head	list;
155	spinlock_t		list_lock;
156	struct kobject		kobj;
157	struct kset_uevent_ops	*uevent_ops;
158};
159
160extern void kset_init(struct kset * k);
161extern int __must_check kset_register(struct kset * k);
162extern void kset_unregister(struct kset * k);
163extern struct kset * __must_check kset_create_and_add(const char *name,
164						struct kset_uevent_ops *u,
165						struct kobject *parent_kobj);
166
167static inline struct kset * to_kset(struct kobject * kobj)
168{
169	return kobj ? container_of(kobj,struct kset,kobj) : NULL;
170}
171
172static inline struct kset * kset_get(struct kset * k)
173{
174	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
175}
176
177static inline void kset_put(struct kset * k)
178{
179	kobject_put(&k->kobj);
180}
181
182static inline struct kobj_type *get_ktype(struct kobject *kobj)
183{
184	return kobj->ktype;
185}
186
187extern struct kobject * kset_find_obj(struct kset *, const char *);
188
189
190/*
191 * Use this when initializing an embedded kset with no other
192 * fields to initialize.
193 */
194#define set_kset_name(str)	.kset = { .kobj = { .k_name = str } }
195
196
197/* The global /sys/kernel/ kobject for people to chain off of */
198extern struct kobject *kernel_kobj;
199/* The global /sys/hypervisor/ kobject for people to chain off of */
200extern struct kobject *hypervisor_kobj;
201/* The global /sys/power/ kobject for people to chain off of */
202extern struct kobject *power_kobj;
203/* The global /sys/firmware/ kobject for people to chain off of */
204extern struct kobject *firmware_kobj;
205
206#if defined(CONFIG_HOTPLUG)
207int kobject_uevent(struct kobject *kobj, enum kobject_action action);
208int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
209			char *envp[]);
210
211int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
212	__attribute__((format (printf, 2, 3)));
213
214int kobject_action_type(const char *buf, size_t count,
215			enum kobject_action *type);
216#else
217static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
218{ return 0; }
219static inline int kobject_uevent_env(struct kobject *kobj,
220				      enum kobject_action action,
221				      char *envp[])
222{ return 0; }
223
224static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
225{ return 0; }
226
227static inline int kobject_action_type(const char *buf, size_t count,
228			enum kobject_action *type)
229{ return -EINVAL; }
230#endif
231
232#endif /* __KERNEL__ */
233#endif /* _KOBJECT_H_ */
234