kobject.h revision b38360a284f8acab4ae431b387c05a4e19ff4129 
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/kobject_ns.h>
26#include <linux/kernel.h>
27#include <linux/wait.h>
28#include <asm/atomic.h>
29
30#define UEVENT_HELPER_PATH_LEN		256
31#define UEVENT_NUM_ENVP			32	/* number of env pointers */
32#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */
33
34/* path to the userspace helper executed on an event */
35extern char uevent_helper[];
36
37/* counter to tag the uevent, read only except for the kobject core */
38extern u64 uevent_seqnum;
39
40/*
41 * The actions here must match the index to the string array
42 * in lib/kobject_uevent.c
43 *
44 * Do not add new actions here without checking with the driver-core
45 * maintainers. Action strings are not meant to express subsystem
46 * or device specific properties. In most cases you want to send a
47 * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
48 * specific variables added to the event environment.
49 */
50enum kobject_action {
51	KOBJ_ADD,
52	KOBJ_REMOVE,
53	KOBJ_CHANGE,
54	KOBJ_MOVE,
55	KOBJ_ONLINE,
56	KOBJ_OFFLINE,
57	KOBJ_MAX
58};
59
60struct kobject {
61	const char		*name;
62	struct list_head	entry;
63	struct kobject		*parent;
64	struct kset		*kset;
65	struct kobj_type	*ktype;
66	struct sysfs_dirent	*sd;
67	struct kref		kref;
68	unsigned int state_initialized:1;
69	unsigned int state_in_sysfs:1;
70	unsigned int state_add_uevent_sent:1;
71	unsigned int state_remove_uevent_sent:1;
72	unsigned int uevent_suppress:1;
73};
74
75extern int kobject_set_name(struct kobject *kobj, const char *name, ...)
76			    __attribute__((format(printf, 2, 3)));
77extern int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
78				  va_list vargs);
79
80static inline const char *kobject_name(const struct kobject *kobj)
81{
82	return kobj->name;
83}
84
85extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
86extern int __must_check kobject_add(struct kobject *kobj,
87				    struct kobject *parent,
88				    const char *fmt, ...)
89	__attribute__((format(printf, 3, 4)));
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	__attribute__((format(printf, 4, 5)));
95
96extern void kobject_del(struct kobject *kobj);
97
98extern struct kobject * __must_check kobject_create(void);
99extern struct kobject * __must_check kobject_create_and_add(const char *name,
100						struct kobject *parent);
101
102extern int __must_check kobject_rename(struct kobject *, const char *new_name);
103extern int __must_check kobject_move(struct kobject *, struct kobject *);
104
105extern struct kobject *kobject_get(struct kobject *kobj);
106extern void kobject_put(struct kobject *kobj);
107
108extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
109
110struct kobj_type {
111	void (*release)(struct kobject *kobj);
112	const struct sysfs_ops *sysfs_ops;
113	struct attribute **default_attrs;
114	const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
115	const void *(*namespace)(struct kobject *kobj);
116};
117
118struct kobj_uevent_env {
119	char *envp[UEVENT_NUM_ENVP];
120	int envp_idx;
121	char buf[UEVENT_BUFFER_SIZE];
122	int buflen;
123};
124
125struct kset_uevent_ops {
126	int (* const filter)(struct kset *kset, struct kobject *kobj);
127	const char *(* const name)(struct kset *kset, struct kobject *kobj);
128	int (* const uevent)(struct kset *kset, struct kobject *kobj,
129		      struct kobj_uevent_env *env);
130};
131
132struct kobj_attribute {
133	struct attribute attr;
134	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
135			char *buf);
136	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
137			 const char *buf, size_t count);
138};
139
140extern const struct sysfs_ops kobj_sysfs_ops;
141
142struct sock;
143
144/**
145 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
146 *
147 * A kset defines a group of kobjects.  They can be individually
148 * different "types" but overall these kobjects all want to be grouped
149 * together and operated on in the same manner.  ksets are used to
150 * define the attribute callbacks and other common events that happen to
151 * a kobject.
152 *
153 * @list: the list of all kobjects for this kset
154 * @list_lock: a lock for iterating over the kobjects
155 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
156 * @uevent_ops: the set of uevent operations for this kset.  These are
157 * called whenever a kobject has something happen to it so that the kset
158 * can add new environment variables, or filter out the uevents if so
159 * desired.
160 */
161struct kset {
162	struct list_head list;
163	spinlock_t list_lock;
164	struct kobject kobj;
165	const struct kset_uevent_ops *uevent_ops;
166};
167
168extern void kset_init(struct kset *kset);
169extern int __must_check kset_register(struct kset *kset);
170extern void kset_unregister(struct kset *kset);
171extern struct kset * __must_check kset_create_and_add(const char *name,
172						const struct kset_uevent_ops *u,
173						struct kobject *parent_kobj);
174
175static inline struct kset *to_kset(struct kobject *kobj)
176{
177	return kobj ? container_of(kobj, struct kset, kobj) : NULL;
178}
179
180static inline struct kset *kset_get(struct kset *k)
181{
182	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
183}
184
185static inline void kset_put(struct kset *k)
186{
187	kobject_put(&k->kobj);
188}
189
190static inline struct kobj_type *get_ktype(struct kobject *kobj)
191{
192	return kobj->ktype;
193}
194
195extern struct kobject *kset_find_obj(struct kset *, const char *);
196extern struct kobject *kset_find_obj_hinted(struct kset *, const char *,
197						struct kobject *);
198
199/* The global /sys/kernel/ kobject for people to chain off of */
200extern struct kobject *kernel_kobj;
201/* The global /sys/kernel/mm/ kobject for people to chain off of */
202extern struct kobject *mm_kobj;
203/* The global /sys/hypervisor/ kobject for people to chain off of */
204extern struct kobject *hypervisor_kobj;
205/* The global /sys/power/ kobject for people to chain off of */
206extern struct kobject *power_kobj;
207/* The global /sys/firmware/ kobject for people to chain off of */
208extern struct kobject *firmware_kobj;
209
210#if defined(CONFIG_HOTPLUG)
211int kobject_uevent(struct kobject *kobj, enum kobject_action action);
212int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
213			char *envp[]);
214
215int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
216	__attribute__((format (printf, 2, 3)));
217
218int kobject_action_type(const char *buf, size_t count,
219			enum kobject_action *type);
220#else
221static inline int kobject_uevent(struct kobject *kobj,
222				 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 __attribute__((format(printf, 2, 3)))
230int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
231{ return 0; }
232
233static inline int kobject_action_type(const char *buf, size_t count,
234				      enum kobject_action *type)
235{ return -EINVAL; }
236#endif
237
238#endif /* _KOBJECT_H_ */
239