kobject.h revision f0e7e1bd77d450ebfa12153b90f93ad46616ab4a 
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_cleanup(struct kobject *);
83
84extern int __must_check kobject_add(struct kobject *);
85extern void kobject_del(struct kobject *);
86
87extern int __must_check kobject_rename(struct kobject *, const char *new_name);
88extern int __must_check kobject_move(struct kobject *, struct kobject *);
89
90extern int __must_check kobject_register(struct kobject *);
91extern void kobject_unregister(struct kobject *);
92
93extern struct kobject * kobject_get(struct kobject *);
94extern void kobject_put(struct kobject *);
95
96extern struct kobject *kobject_kset_add_dir(struct kset *kset,
97					    struct kobject *, const char *);
98extern struct kobject *kobject_add_dir(struct kobject *, const char *);
99
100extern char * kobject_get_path(struct kobject *, gfp_t);
101
102struct kobj_type {
103	void (*release)(struct kobject *);
104	struct sysfs_ops	* sysfs_ops;
105	struct attribute	** default_attrs;
106};
107
108struct kobj_uevent_env {
109	char *envp[UEVENT_NUM_ENVP];
110	int envp_idx;
111	char buf[UEVENT_BUFFER_SIZE];
112	int buflen;
113};
114
115struct kset_uevent_ops {
116	int (*filter)(struct kset *kset, struct kobject *kobj);
117	const char *(*name)(struct kset *kset, struct kobject *kobj);
118	int (*uevent)(struct kset *kset, struct kobject *kobj,
119		      struct kobj_uevent_env *env);
120};
121
122/**
123 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
124 *
125 * A kset defines a group of kobjects.  They can be individually
126 * different "types" but overall these kobjects all want to be grouped
127 * together and operated on in the same manner.  ksets are used to
128 * define the attribute callbacks and other common events that happen to
129 * a kobject.
130 *
131 * @ktype: the struct kobj_type for this specific kset
132 * @list: the list of all kobjects for this kset
133 * @list_lock: a lock for iterating over the kobjects
134 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
135 * @uevent_ops: the set of uevent operations for this kset.  These are
136 * called whenever a kobject has something happen to it so that the kset
137 * can add new environment variables, or filter out the uevents if so
138 * desired.
139 */
140struct kset {
141	struct kobj_type	*ktype;
142	struct list_head	list;
143	spinlock_t		list_lock;
144	struct kobject		kobj;
145	struct kset_uevent_ops	*uevent_ops;
146};
147
148
149extern void kset_init(struct kset * k);
150extern int __must_check kset_add(struct kset * k);
151extern int __must_check kset_register(struct kset * k);
152extern void kset_unregister(struct kset * k);
153
154static inline struct kset * to_kset(struct kobject * kobj)
155{
156	return kobj ? container_of(kobj,struct kset,kobj) : NULL;
157}
158
159static inline struct kset * kset_get(struct kset * k)
160{
161	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
162}
163
164static inline void kset_put(struct kset * k)
165{
166	kobject_put(&k->kobj);
167}
168
169static inline struct kobj_type * get_ktype(struct kobject * k)
170{
171	if (k->kset && k->kset->ktype)
172		return k->kset->ktype;
173	else
174		return k->ktype;
175}
176
177extern struct kobject * kset_find_obj(struct kset *, const char *);
178
179
180/*
181 * Use this when initializing an embedded kset with no other
182 * fields to initialize.
183 */
184#define set_kset_name(str)	.kset = { .kobj = { .k_name = str } }
185
186
187#define decl_subsys(_name,_type,_uevent_ops) \
188struct kset _name##_subsys = { \
189	.kobj = { .k_name = __stringify(_name) }, \
190	.ktype = _type, \
191	.uevent_ops =_uevent_ops, \
192}
193#define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
194struct kset _varname##_subsys = { \
195	.kobj = { .k_name = __stringify(_name) }, \
196	.ktype = _type, \
197	.uevent_ops =_uevent_ops, \
198}
199
200/* The global /sys/kernel/ subsystem for people to chain off of */
201extern struct kset kernel_subsys;
202/* The global /sys/hypervisor/ subsystem  */
203extern struct kset hypervisor_subsys;
204
205/*
206 * Helpers for setting the kset of registered objects.
207 * Often, a registered object belongs to a kset embedded in a
208 * subsystem. These do no magic, just make the resulting code
209 * easier to follow.
210 */
211
212/**
213 *	kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
214 *	@obj:		ptr to some object type.
215 *	@subsys:	a subsystem object (not a ptr).
216 *
217 *	Can be used for any object type with an embedded ->kobj.
218 */
219
220#define kobj_set_kset_s(obj,subsys) \
221	(obj)->kobj.kset = &(subsys)
222
223extern int __must_check subsystem_register(struct kset *);
224extern void subsystem_unregister(struct kset *);
225
226struct subsys_attribute {
227	struct attribute attr;
228	ssize_t (*show)(struct kset *, char *);
229	ssize_t (*store)(struct kset *, const char *, size_t);
230};
231
232extern int __must_check subsys_create_file(struct kset *,
233					struct subsys_attribute *);
234
235#if defined(CONFIG_HOTPLUG)
236int kobject_uevent(struct kobject *kobj, enum kobject_action action);
237int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
238			char *envp[]);
239
240int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
241	__attribute__((format (printf, 2, 3)));
242
243int kobject_action_type(const char *buf, size_t count,
244			enum kobject_action *type);
245#else
246static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
247{ return 0; }
248static inline int kobject_uevent_env(struct kobject *kobj,
249				      enum kobject_action action,
250				      char *envp[])
251{ return 0; }
252
253static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
254{ return 0; }
255
256static inline int kobject_action_type(const char *buf, size_t count,
257			enum kobject_action *type)
258{ return -EINVAL; }
259#endif
260
261#endif /* __KERNEL__ */
262#endif /* _KOBJECT_H_ */
263