kobject.h revision f67f129e519fa87f8ebd236b6336fe43f31ee141 
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) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
7 * Copyright (c) 2006-2008 Novell Inc.
8 *
9 * This file is released under the GPLv2.
10 *
11 * Please read Documentation/kobject.txt before using the kobject
12 * interface, ESPECIALLY the parts about reference counts and object
13 * destructors.
14 */
15
16#ifndef _KOBJECT_H_
17#define _KOBJECT_H_
18
19#include <linux/types.h>
20#include <linux/list.h>
21#include <linux/sysfs.h>
22#include <linux/compiler.h>
23#include <linux/spinlock.h>
24#include <linux/kref.h>
25#include <linux/kernel.h>
26#include <linux/wait.h>
27#include <asm/atomic.h>
28
29#define UEVENT_HELPER_PATH_LEN		256
30#define UEVENT_NUM_ENVP			32	/* number of env pointers */
31#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */
32
33/* path to the userspace helper executed on an event */
34extern char uevent_helper[];
35
36/* counter to tag the uevent, read only except for the kobject core */
37extern u64 uevent_seqnum;
38
39/*
40 * The actions here must match the index to the string array
41 * in lib/kobject_uevent.c
42 *
43 * Do not add new actions here without checking with the driver-core
44 * maintainers. Action strings are not meant to express subsystem
45 * or device specific properties. In most cases you want to send a
46 * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
47 * specific variables added to the event environment.
48 */
49enum kobject_action {
50	KOBJ_ADD,
51	KOBJ_REMOVE,
52	KOBJ_CHANGE,
53	KOBJ_MOVE,
54	KOBJ_ONLINE,
55	KOBJ_OFFLINE,
56	KOBJ_MAX
57};
58
59struct kobject {
60	const char		*name;
61	struct list_head	entry;
62	struct kobject		*parent;
63	struct kset		*kset;
64	struct kobj_type	*ktype;
65	struct sysfs_dirent	*sd;
66	struct kref		kref;
67	unsigned int state_initialized:1;
68	unsigned int state_in_sysfs:1;
69	unsigned int state_add_uevent_sent:1;
70	unsigned int state_remove_uevent_sent:1;
71	unsigned int uevent_suppress:1;
72};
73
74extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
75			    __attribute__((format(printf, 2, 3)));
76extern int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
77				  va_list vargs);
78
79static inline const char *kobject_name(const struct kobject *kobj)
80{
81	return kobj->name;
82}
83
84extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
85extern int __must_check kobject_add(struct kobject *kobj,
86				    struct kobject *parent,
87				    const char *fmt, ...);
88extern int __must_check kobject_init_and_add(struct kobject *kobj,
89					     struct kobj_type *ktype,
90					     struct kobject *parent,
91					     const char *fmt, ...);
92
93extern void kobject_del(struct kobject *kobj);
94
95extern struct kobject * __must_check kobject_create(void);
96extern struct kobject * __must_check kobject_create_and_add(const char *name,
97						struct kobject *parent);
98
99extern int __must_check kobject_rename(struct kobject *, const char *new_name);
100extern int __must_check kobject_move(struct kobject *, struct kobject *);
101
102extern struct kobject *kobject_get(struct kobject *kobj);
103extern void kobject_put(struct kobject *kobj);
104
105extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
106
107struct kobj_type {
108	void (*release)(struct kobject *kobj);
109	struct sysfs_ops *sysfs_ops;
110	struct attribute **default_attrs;
111};
112
113struct kobj_uevent_env {
114	char *envp[UEVENT_NUM_ENVP];
115	int envp_idx;
116	char buf[UEVENT_BUFFER_SIZE];
117	int buflen;
118};
119
120struct kset_uevent_ops {
121	int (*filter)(struct kset *kset, struct kobject *kobj);
122	const char *(*name)(struct kset *kset, struct kobject *kobj);
123	int (*uevent)(struct kset *kset, struct kobject *kobj,
124		      struct kobj_uevent_env *env);
125};
126
127struct kobj_attribute {
128	struct attribute attr;
129	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
130			char *buf);
131	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
132			 const char *buf, size_t count);
133};
134
135extern struct sysfs_ops kobj_sysfs_ops;
136
137/**
138 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
139 *
140 * A kset defines a group of kobjects.  They can be individually
141 * different "types" but overall these kobjects all want to be grouped
142 * together and operated on in the same manner.  ksets are used to
143 * define the attribute callbacks and other common events that happen to
144 * a kobject.
145 *
146 * @list: the list of all kobjects for this kset
147 * @list_lock: a lock for iterating over the kobjects
148 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
149 * @uevent_ops: the set of uevent operations for this kset.  These are
150 * called whenever a kobject has something happen to it so that the kset
151 * can add new environment variables, or filter out the uevents if so
152 * desired.
153 */
154struct kset {
155	struct list_head list;
156	spinlock_t list_lock;
157	struct kobject kobj;
158	struct kset_uevent_ops *uevent_ops;
159};
160
161extern void kset_init(struct kset *kset);
162extern int __must_check kset_register(struct kset *kset);
163extern void kset_unregister(struct kset *kset);
164extern struct kset * __must_check kset_create_and_add(const char *name,
165						struct kset_uevent_ops *u,
166						struct kobject *parent_kobj);
167
168static inline struct kset *to_kset(struct kobject *kobj)
169{
170	return kobj ? container_of(kobj, struct kset, kobj) : NULL;
171}
172
173static inline struct kset *kset_get(struct kset *k)
174{
175	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
176}
177
178static inline void kset_put(struct kset *k)
179{
180	kobject_put(&k->kobj);
181}
182
183static inline struct kobj_type *get_ktype(struct kobject *kobj)
184{
185	return kobj->ktype;
186}
187
188extern struct kobject *kset_find_obj(struct kset *, const char *);
189
190/* The global /sys/kernel/ kobject for people to chain off of */
191extern struct kobject *kernel_kobj;
192/* The global /sys/kernel/mm/ kobject for people to chain off of */
193extern struct kobject *mm_kobj;
194/* The global /sys/hypervisor/ kobject for people to chain off of */
195extern struct kobject *hypervisor_kobj;
196/* The global /sys/power/ kobject for people to chain off of */
197extern struct kobject *power_kobj;
198/* The global /sys/firmware/ kobject for people to chain off of */
199extern struct kobject *firmware_kobj;
200
201#if defined(CONFIG_HOTPLUG)
202int kobject_uevent(struct kobject *kobj, enum kobject_action action);
203int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
204			char *envp[]);
205
206int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
207	__attribute__((format (printf, 2, 3)));
208
209int kobject_action_type(const char *buf, size_t count,
210			enum kobject_action *type);
211#else
212static inline int kobject_uevent(struct kobject *kobj,
213				 enum kobject_action action)
214{ return 0; }
215static inline int kobject_uevent_env(struct kobject *kobj,
216				      enum kobject_action action,
217				      char *envp[])
218{ return 0; }
219
220static inline int add_uevent_var(struct kobj_uevent_env *env,
221				 const char *format, ...)
222{ return 0; }
223
224static inline int kobject_action_type(const char *buf, size_t count,
225				      enum kobject_action *type)
226{ return -EINVAL; }
227#endif
228
229#endif /* _KOBJECT_H_ */
230