kobject.h revision 4ff6abff832fbc6cb1d769f6106c841bc2b09f63 
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_and_add(const char *name,
95						struct kobject *parent);
96
97extern int __must_check kobject_rename(struct kobject *, const char *new_name);
98extern int __must_check kobject_move(struct kobject *, struct kobject *);
99
100extern int __must_check kobject_register(struct kobject *);
101extern void kobject_unregister(struct kobject *);
102
103extern struct kobject * kobject_get(struct kobject *);
104extern void kobject_put(struct kobject *);
105
106extern struct kobject *kobject_kset_add_dir(struct kset *kset,
107					    struct kobject *, const char *);
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
131/**
132 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
133 *
134 * A kset defines a group of kobjects.  They can be individually
135 * different "types" but overall these kobjects all want to be grouped
136 * together and operated on in the same manner.  ksets are used to
137 * define the attribute callbacks and other common events that happen to
138 * a kobject.
139 *
140 * @list: the list of all kobjects for this kset
141 * @list_lock: a lock for iterating over the kobjects
142 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
143 * @uevent_ops: the set of uevent operations for this kset.  These are
144 * called whenever a kobject has something happen to it so that the kset
145 * can add new environment variables, or filter out the uevents if so
146 * desired.
147 */
148struct kset {
149	struct list_head	list;
150	spinlock_t		list_lock;
151	struct kobject		kobj;
152	struct kset_uevent_ops	*uevent_ops;
153};
154
155extern void kset_init(struct kset * k);
156extern int __must_check kset_add(struct kset * k);
157extern int __must_check kset_register(struct kset * k);
158extern void kset_unregister(struct kset * k);
159extern struct kset * __must_check kset_create_and_add(const char *name,
160						struct kset_uevent_ops *u,
161						struct kobject *parent_kobj);
162
163static inline struct kset * to_kset(struct kobject * kobj)
164{
165	return kobj ? container_of(kobj,struct kset,kobj) : NULL;
166}
167
168static inline struct kset * kset_get(struct kset * k)
169{
170	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
171}
172
173static inline void kset_put(struct kset * k)
174{
175	kobject_put(&k->kobj);
176}
177
178static inline struct kobj_type *get_ktype(struct kobject *kobj)
179{
180	return kobj->ktype;
181}
182
183extern struct kobject * kset_find_obj(struct kset *, const char *);
184
185
186/*
187 * Use this when initializing an embedded kset with no other
188 * fields to initialize.
189 */
190#define set_kset_name(str)	.kset = { .kobj = { .k_name = str } }
191
192
193#define decl_subsys(_name,_uevent_ops) \
194struct kset _name##_subsys = { \
195	.kobj = { .k_name = __stringify(_name) }, \
196	.uevent_ops =_uevent_ops, \
197}
198#define decl_subsys_name(_varname,_name,_uevent_ops) \
199struct kset _varname##_subsys = { \
200	.kobj = { .k_name = __stringify(_name) }, \
201	.uevent_ops =_uevent_ops, \
202}
203
204/* The global /sys/kernel/ subsystem for people to chain off of */
205extern struct kset kernel_subsys;
206/* The global /sys/hypervisor/ subsystem  */
207extern struct kset hypervisor_subsys;
208
209extern int __must_check subsystem_register(struct kset *);
210extern void subsystem_unregister(struct kset *);
211
212struct subsys_attribute {
213	struct attribute attr;
214	ssize_t (*show)(struct kset *, char *);
215	ssize_t (*store)(struct kset *, const char *, size_t);
216};
217
218extern int __must_check subsys_create_file(struct kset *,
219					struct subsys_attribute *);
220
221#if defined(CONFIG_HOTPLUG)
222int kobject_uevent(struct kobject *kobj, enum kobject_action action);
223int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
224			char *envp[]);
225
226int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
227	__attribute__((format (printf, 2, 3)));
228
229int kobject_action_type(const char *buf, size_t count,
230			enum kobject_action *type);
231#else
232static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
233{ return 0; }
234static inline int kobject_uevent_env(struct kobject *kobj,
235				      enum kobject_action action,
236				      char *envp[])
237{ return 0; }
238
239static inline int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
240{ return 0; }
241
242static inline int kobject_action_type(const char *buf, size_t count,
243			enum kobject_action *type)
244{ return -EINVAL; }
245#endif
246
247#endif /* __KERNEL__ */
248#endif /* _KOBJECT_H_ */
249