kobject.h revision 0f4dafc0563c6c49e17fe14b3f5f356e4c4b8806 
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	unsigned int state_initialized:1;
72	unsigned int state_name_set:1;
73	unsigned int state_in_sysfs:1;
74	unsigned int state_add_uevent_sent:1;
75	unsigned int state_remove_uevent_sent:1;
76};
77
78extern int kobject_set_name(struct kobject *, const char *, ...)
79	__attribute__((format(printf,2,3)));
80
81static inline const char * kobject_name(const struct kobject * kobj)
82{
83	return kobj->k_name;
84}
85
86extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
87extern int __must_check kobject_add(struct kobject *kobj,
88				    struct kobject *parent,
89				    const char *fmt, ...);
90extern int __must_check kobject_init_and_add(struct kobject *kobj,
91					     struct kobj_type *ktype,
92					     struct kobject *parent,
93					     const char *fmt, ...);
94
95extern void kobject_del(struct kobject *);
96
97extern struct kobject * __must_check kobject_create(void);
98extern struct kobject * __must_check kobject_create_and_add(const char *name,
99						struct kobject *parent);
100
101extern int __must_check kobject_rename(struct kobject *, const char *new_name);
102extern int __must_check kobject_move(struct kobject *, struct kobject *);
103
104extern void kobject_unregister(struct kobject *);
105
106extern struct kobject * kobject_get(struct kobject *);
107extern void kobject_put(struct kobject *);
108
109extern char * kobject_get_path(struct kobject *, gfp_t);
110
111struct kobj_type {
112	void (*release)(struct kobject *);
113	struct sysfs_ops	* sysfs_ops;
114	struct attribute	** default_attrs;
115};
116
117struct kobj_uevent_env {
118	char *envp[UEVENT_NUM_ENVP];
119	int envp_idx;
120	char buf[UEVENT_BUFFER_SIZE];
121	int buflen;
122};
123
124struct kset_uevent_ops {
125	int (*filter)(struct kset *kset, struct kobject *kobj);
126	const char *(*name)(struct kset *kset, struct kobject *kobj);
127	int (*uevent)(struct kset *kset, struct kobject *kobj,
128		      struct kobj_uevent_env *env);
129};
130
131struct kobj_attribute {
132	struct attribute attr;
133	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
134			char *buf);
135	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
136			 const char *buf, size_t count);
137};
138
139extern struct sysfs_ops kobj_sysfs_ops;
140
141/**
142 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
143 *
144 * A kset defines a group of kobjects.  They can be individually
145 * different "types" but overall these kobjects all want to be grouped
146 * together and operated on in the same manner.  ksets are used to
147 * define the attribute callbacks and other common events that happen to
148 * a kobject.
149 *
150 * @list: the list of all kobjects for this kset
151 * @list_lock: a lock for iterating over the kobjects
152 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
153 * @uevent_ops: the set of uevent operations for this kset.  These are
154 * called whenever a kobject has something happen to it so that the kset
155 * can add new environment variables, or filter out the uevents if so
156 * desired.
157 */
158struct kset {
159	struct list_head	list;
160	spinlock_t		list_lock;
161	struct kobject		kobj;
162	struct kset_uevent_ops	*uevent_ops;
163};
164
165extern void kset_init(struct kset * k);
166extern int __must_check kset_register(struct kset * k);
167extern void kset_unregister(struct kset * k);
168extern struct kset * __must_check kset_create_and_add(const char *name,
169						struct kset_uevent_ops *u,
170						struct kobject *parent_kobj);
171
172static inline struct kset * to_kset(struct kobject * kobj)
173{
174	return kobj ? container_of(kobj,struct kset,kobj) : NULL;
175}
176
177static inline struct kset * kset_get(struct kset * k)
178{
179	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
180}
181
182static inline void kset_put(struct kset * k)
183{
184	kobject_put(&k->kobj);
185}
186
187static inline struct kobj_type *get_ktype(struct kobject *kobj)
188{
189	return kobj->ktype;
190}
191
192extern struct kobject * kset_find_obj(struct kset *, const char *);
193
194
195/*
196 * Use this when initializing an embedded kset with no other
197 * fields to initialize.
198 */
199#define set_kset_name(str)	.kset = { .kobj = { .k_name = str } }
200
201
202/* The global /sys/kernel/ kobject for people to chain off of */
203extern struct kobject *kernel_kobj;
204/* The global /sys/hypervisor/ kobject for people to chain off of */
205extern struct kobject *hypervisor_kobj;
206/* The global /sys/power/ kobject for people to chain off of */
207extern struct kobject *power_kobj;
208/* The global /sys/firmware/ kobject for people to chain off of */
209extern struct kobject *firmware_kobj;
210
211#if defined(CONFIG_HOTPLUG)
212int kobject_uevent(struct kobject *kobj, enum kobject_action action);
213int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
214			char *envp[]);
215
216int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
217	__attribute__((format (printf, 2, 3)));
218
219int kobject_action_type(const char *buf, size_t count,
220			enum kobject_action *type);
221#else
222static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
223{ return 0; }
224static inline int kobject_uevent_env(struct kobject *kobj,
225				      enum kobject_action action,
226				      char *envp[])
227{ return 0; }
228
229static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
230{ return 0; }
231
232static inline int kobject_action_type(const char *buf, size_t count,
233			enum kobject_action *type)
234{ return -EINVAL; }
235#endif
236
237#endif /* __KERNEL__ */
238#endif /* _KOBJECT_H_ */
239