kobject.h revision 6adf7554b9c70eac83251e00aa4a55f7dc830cec 
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 *
7 * This file is released under the GPLv2.
8 *
9 *
10 * Please read Documentation/kobject.txt before using the kobject
11 * interface, ESPECIALLY the parts about reference counts and object
12 * destructors.
13 */
14
15#ifndef _KOBJECT_H_
16#define _KOBJECT_H_
17
18#ifdef __KERNEL__
19
20#include <linux/types.h>
21#include <linux/list.h>
22#include <linux/sysfs.h>
23#include <linux/compiler.h>
24#include <linux/spinlock.h>
25#include <linux/kref.h>
26#include <linux/kernel.h>
27#include <linux/wait.h>
28#include <asm/atomic.h>
29
30#define KOBJ_NAME_LEN			20
31#define UEVENT_HELPER_PATH_LEN		256
32#define UEVENT_NUM_ENVP			32	/* number of env pointers */
33#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */
34
35/* path to the userspace helper executed on an event */
36extern char uevent_helper[];
37
38/* counter to tag the uevent, read only except for the kobject core */
39extern u64 uevent_seqnum;
40
41/*
42 * The actions here must match the index to the string array
43 * in lib/kobject_uevent.c
44 *
45 * Do not add new actions here without checking with the driver-core
46 * maintainers. Action strings are not meant to express subsystem
47 * or device specific properties. In most cases you want to send a
48 * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
49 * specific variables added to the event environment.
50 */
51enum kobject_action {
52	KOBJ_ADD,
53	KOBJ_REMOVE,
54	KOBJ_CHANGE,
55	KOBJ_MOVE,
56	KOBJ_ONLINE,
57	KOBJ_OFFLINE,
58	KOBJ_MAX
59};
60
61struct kobject {
62	const char		* k_name;
63	struct kref		kref;
64	struct list_head	entry;
65	struct kobject		* parent;
66	struct kset		* kset;
67	struct kobj_type	* ktype;
68	struct sysfs_dirent	* sd;
69};
70
71extern int kobject_set_name(struct kobject *, const char *, ...)
72	__attribute__((format(printf,2,3)));
73
74static inline const char * kobject_name(const struct kobject * kobj)
75{
76	return kobj->k_name;
77}
78
79extern void kobject_init(struct kobject *);
80extern void kobject_cleanup(struct kobject *);
81
82extern int __must_check kobject_add(struct kobject *);
83extern void kobject_del(struct kobject *);
84
85extern int __must_check kobject_rename(struct kobject *, const char *new_name);
86extern int __must_check kobject_move(struct kobject *, struct kobject *);
87
88extern int __must_check kobject_register(struct kobject *);
89extern void kobject_unregister(struct kobject *);
90
91extern struct kobject * kobject_get(struct kobject *);
92extern void kobject_put(struct kobject *);
93
94extern struct kobject *kobject_kset_add_dir(struct kset *kset,
95					    struct kobject *, const char *);
96extern struct kobject *kobject_add_dir(struct kobject *, const char *);
97
98extern char * kobject_get_path(struct kobject *, gfp_t);
99
100struct kobj_type {
101	void (*release)(struct kobject *);
102	struct sysfs_ops	* sysfs_ops;
103	struct attribute	** default_attrs;
104};
105
106struct kobj_uevent_env {
107	char *envp[UEVENT_NUM_ENVP];
108	int envp_idx;
109	char buf[UEVENT_BUFFER_SIZE];
110	int buflen;
111};
112
113struct kset_uevent_ops {
114	int (*filter)(struct kset *kset, struct kobject *kobj);
115	const char *(*name)(struct kset *kset, struct kobject *kobj);
116	int (*uevent)(struct kset *kset, struct kobject *kobj,
117		      struct kobj_uevent_env *env);
118};
119
120/**
121 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
122 *
123 * A kset defines a group of kobjects.  They can be individually
124 * different "types" but overall these kobjects all want to be grouped
125 * together and operated on in the same manner.  ksets are used to
126 * define the attribute callbacks and other common events that happen to
127 * a kobject.
128 *
129 * @ktype: the struct kobj_type for this specific kset
130 * @list: the list of all kobjects for this kset
131 * @list_lock: a lock for iterating over the kobjects
132 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
133 * @uevent_ops: the set of uevent operations for this kset.  These are
134 * called whenever a kobject has something happen to it so that the kset
135 * can add new environment variables, or filter out the uevents if so
136 * desired.
137 */
138struct kset {
139	struct kobj_type	*ktype;
140	struct list_head	list;
141	spinlock_t		list_lock;
142	struct kobject		kobj;
143	struct kset_uevent_ops	*uevent_ops;
144};
145
146
147extern void kset_init(struct kset * k);
148extern int __must_check kset_add(struct kset * k);
149extern int __must_check kset_register(struct kset * k);
150extern void kset_unregister(struct kset * k);
151
152static inline struct kset * to_kset(struct kobject * kobj)
153{
154	return kobj ? container_of(kobj,struct kset,kobj) : NULL;
155}
156
157static inline struct kset * kset_get(struct kset * k)
158{
159	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
160}
161
162static inline void kset_put(struct kset * k)
163{
164	kobject_put(&k->kobj);
165}
166
167static inline struct kobj_type * get_ktype(struct kobject * k)
168{
169	if (k->kset && k->kset->ktype)
170		return k->kset->ktype;
171	else
172		return k->ktype;
173}
174
175extern struct kobject * kset_find_obj(struct kset *, const char *);
176
177
178/*
179 * Use this when initializing an embedded kset with no other
180 * fields to initialize.
181 */
182#define set_kset_name(str)	.kset = { .kobj = { .k_name = str } }
183
184
185#define decl_subsys(_name,_type,_uevent_ops) \
186struct kset _name##_subsys = { \
187	.kobj = { .k_name = __stringify(_name) }, \
188	.ktype = _type, \
189	.uevent_ops =_uevent_ops, \
190}
191#define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
192struct kset _varname##_subsys = { \
193	.kobj = { .k_name = __stringify(_name) }, \
194	.ktype = _type, \
195	.uevent_ops =_uevent_ops, \
196}
197
198/* The global /sys/kernel/ subsystem for people to chain off of */
199extern struct kset kernel_subsys;
200/* The global /sys/hypervisor/ subsystem  */
201extern struct kset hypervisor_subsys;
202
203/*
204 * Helpers for setting the kset of registered objects.
205 * Often, a registered object belongs to a kset embedded in a
206 * subsystem. These do no magic, just make the resulting code
207 * easier to follow.
208 */
209
210/**
211 *	kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
212 *	@obj:		ptr to some object type.
213 *	@subsys:	a subsystem object (not a ptr).
214 *
215 *	Can be used for any object type with an embedded ->kobj.
216 */
217
218#define kobj_set_kset_s(obj,subsys) \
219	(obj)->kobj.kset = &(subsys)
220
221extern int __must_check subsystem_register(struct kset *);
222extern void subsystem_unregister(struct kset *);
223
224struct subsys_attribute {
225	struct attribute attr;
226	ssize_t (*show)(struct kset *, char *);
227	ssize_t (*store)(struct kset *, const char *, size_t);
228};
229
230extern int __must_check subsys_create_file(struct kset *,
231					struct subsys_attribute *);
232
233#if defined(CONFIG_HOTPLUG)
234int kobject_uevent(struct kobject *kobj, enum kobject_action action);
235int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
236			char *envp[]);
237
238int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
239	__attribute__((format (printf, 2, 3)));
240
241int kobject_action_type(const char *buf, size_t count,
242			enum kobject_action *type);
243#else
244static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
245{ return 0; }
246static inline int kobject_uevent_env(struct kobject *kobj,
247				      enum kobject_action action,
248				      char *envp[])
249{ return 0; }
250
251static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
252{ return 0; }
253
254static inline int kobject_action_type(const char *buf, size_t count,
255			enum kobject_action *type)
256{ return -EINVAL; }
257#endif
258
259#endif /* __KERNEL__ */
260#endif /* _KOBJECT_H_ */
261