kobject.h

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * kobject.h - generic kernel object infrastructure.
  4 *
  5 * Copyright (c) 2002-2003 Patrick Mochel
  6 * Copyright (c) 2002-2003 Open Source Development Labs
  7 * Copyright (c) 2006-2008 Greg Kroah-Hartman <greg@kroah.com>
  8 * Copyright (c) 2006-2008 Novell Inc.
  9 *
 10 * Please read Documentation/core-api/kobject.rst 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#include <linux/types.h>
 19#include <linux/list.h>
 20#include <linux/sysfs.h>
 21#include <linux/compiler.h>
 22#include <linux/container_of.h>
 23#include <linux/spinlock.h>
 24#include <linux/kref.h>
 25#include <linux/kobject_ns.h>
 26#include <linux/wait.h>
 27#include <linux/atomic.h>
 28#include <linux/workqueue.h>
 29#include <linux/uidgid.h>
 30
 31#define UEVENT_HELPER_PATH_LEN		256
 32#define UEVENT_NUM_ENVP			64	/* number of env pointers */
 33#define UEVENT_BUFFER_SIZE		2048	/* buffer for the variables */
 34
 35#ifdef CONFIG_UEVENT_HELPER
 36/* path to the userspace helper executed on an event */
 37extern char uevent_helper[];
 38#endif
 39
 40/* counter to tag the uevent, read only except for the kobject core */
 41extern atomic64_t 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_BIND,
 61	KOBJ_UNBIND,
 62};
 63
 64struct kobject {
 65	const char		*name;
 66	struct list_head	entry;
 67	struct kobject		*parent;
 68	struct kset		*kset;
 69	const struct kobj_type	*ktype;
 70	struct kernfs_node	*sd; /* sysfs directory entry */
 71	struct kref		kref;
 72
 73	unsigned int state_initialized:1;
 74	unsigned int state_in_sysfs:1;
 75	unsigned int state_add_uevent_sent:1;
 76	unsigned int state_remove_uevent_sent:1;
 77	unsigned int uevent_suppress:1;
 78
 79#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
 80	struct delayed_work	release;
 81#endif
 82};
 83
 84__printf(2, 3) int kobject_set_name(struct kobject *kobj, const char *name, ...);
 85__printf(2, 0) int kobject_set_name_vargs(struct kobject *kobj, const char *fmt, va_list vargs);
 86
 87static inline const char *kobject_name(const struct kobject *kobj)
 88{
 89	return kobj->name;
 90}
 91
 92void kobject_init(struct kobject *kobj, const struct kobj_type *ktype);
 93__printf(3, 4) __must_check int kobject_add(struct kobject *kobj,
 94					    struct kobject *parent,
 95					    const char *fmt, ...);
 96__printf(4, 5) __must_check int kobject_init_and_add(struct kobject *kobj,
 97						     const struct kobj_type *ktype,
 98						     struct kobject *parent,
 99						     const char *fmt, ...);
100
101void kobject_del(struct kobject *kobj);
102
103struct kobject * __must_check kobject_create_and_add(const char *name, struct kobject *parent);
104
105int __must_check kobject_rename(struct kobject *, const char *new_name);
106int __must_check kobject_move(struct kobject *, struct kobject *);
107
108struct kobject *kobject_get(struct kobject *kobj);
109struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj);
110void kobject_put(struct kobject *kobj);
111
112const void *kobject_namespace(const struct kobject *kobj);
113void kobject_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid);
114char *kobject_get_path(const struct kobject *kobj, gfp_t flag);
115
116struct kobj_type {
117	void (*release)(struct kobject *kobj);
118	const struct sysfs_ops *sysfs_ops;
119	const struct attribute_group **default_groups;
120	const struct kobj_ns_type_operations *(*child_ns_type)(const struct kobject *kobj);
121	const void *(*namespace)(const struct kobject *kobj);
122	void (*get_ownership)(const struct kobject *kobj, kuid_t *uid, kgid_t *gid);
123};
124
125struct kobj_uevent_env {
126	char *argv[3];
127	char *envp[UEVENT_NUM_ENVP];
128	int envp_idx;
129	char buf[UEVENT_BUFFER_SIZE];
130	int buflen;
131};
132
133struct kset_uevent_ops {
134	int (* const filter)(const struct kobject *kobj);
135	const char *(* const name)(const struct kobject *kobj);
136	int (* const uevent)(const struct kobject *kobj, struct kobj_uevent_env *env);
137};
138
139struct kobj_attribute {
140	struct attribute attr;
141	ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
142			char *buf);
143	ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
144			 const char *buf, size_t count);
145};
146
147extern const struct sysfs_ops kobj_sysfs_ops;
148
149struct sock;
150
151/**
152 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
153 *
154 * A kset defines a group of kobjects.  They can be individually
155 * different "types" but overall these kobjects all want to be grouped
156 * together and operated on in the same manner.  ksets are used to
157 * define the attribute callbacks and other common events that happen to
158 * a kobject.
159 *
160 * @list: the list of all kobjects for this kset
161 * @list_lock: a lock for iterating over the kobjects
162 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
163 * @uevent_ops: the set of uevent operations for this kset.  These are
164 * called whenever a kobject has something happen to it so that the kset
165 * can add new environment variables, or filter out the uevents if so
166 * desired.
167 */
168struct kset {
169	struct list_head list;
170	spinlock_t list_lock;
171	struct kobject kobj;
172	const struct kset_uevent_ops *uevent_ops;
173} __randomize_layout;
174
175void kset_init(struct kset *kset);
176int __must_check kset_register(struct kset *kset);
177void kset_unregister(struct kset *kset);
178struct kset * __must_check kset_create_and_add(const char *name, const struct kset_uevent_ops *u,
179					       struct kobject *parent_kobj);
180
181static inline struct kset *to_kset(struct kobject *kobj)
182{
183	return kobj ? container_of(kobj, struct kset, kobj) : NULL;
184}
185
186static inline struct kset *kset_get(struct kset *k)
187{
188	return k ? to_kset(kobject_get(&k->kobj)) : NULL;
189}
190
191static inline void kset_put(struct kset *k)
192{
193	kobject_put(&k->kobj);
194}
195
196static inline const struct kobj_type *get_ktype(const struct kobject *kobj)
197{
198	return kobj->ktype;
199}
200
201struct kobject *kset_find_obj(struct kset *, const char *);
202
203/* The global /sys/kernel/ kobject for people to chain off of */
204extern struct kobject *kernel_kobj;
205/* The global /sys/kernel/mm/ kobject for people to chain off of */
206extern struct kobject *mm_kobj;
207/* The global /sys/hypervisor/ kobject for people to chain off of */
208extern struct kobject *hypervisor_kobj;
209/* The global /sys/power/ kobject for people to chain off of */
210extern struct kobject *power_kobj;
211/* The global /sys/firmware/ kobject for people to chain off of */
212extern struct kobject *firmware_kobj;
213
214int kobject_uevent(struct kobject *kobj, enum kobject_action action);
215int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
216			char *envp[]);
217int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
218
219__printf(2, 3)
220int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
221
222#endif /* _KOBJECT_H_ */