LXR linux/include/linux/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/spinlock.h>
  23#include <linux/kref.h>
  24#include <linux/kobject_ns.h>
  25#include <linux/kernel.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 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_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        struct kobj_type        *ktype;
  70        struct kernfs_node      *sd; /* sysfs directory entry */
  71        struct kref             kref;
  72#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
  73        struct delayed_work     release;
  74#endif
  75        unsigned int state_initialized:1;
  76        unsigned int state_in_sysfs:1;
  77        unsigned int state_add_uevent_sent:1;
  78        unsigned int state_remove_uevent_sent:1;
  79        unsigned int uevent_suppress:1;
  80};
  81
  82extern __printf(2, 3)
  83int kobject_set_name(struct kobject *kobj, const char *name, ...);
  84extern __printf(2, 0)
  85int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
  86                           va_list vargs);
  87
  88static inline const char *kobject_name(const struct kobject *kobj)
  89{
  90        return kobj->name;
  91}
  92
  93extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  94extern __printf(3, 4) __must_check
  95int kobject_add(struct kobject *kobj, struct kobject *parent,
  96                const char *fmt, ...);
  97extern __printf(4, 5) __must_check
  98int kobject_init_and_add(struct kobject *kobj,
  99                         struct kobj_type *ktype, struct kobject *parent,
 100                         const char *fmt, ...);
 101
 102extern void kobject_del(struct kobject *kobj);
 103
 104extern struct kobject * __must_check kobject_create_and_add(const char *name,
 105                                                struct kobject *parent);
 106
 107extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 108extern int __must_check kobject_move(struct kobject *, struct kobject *);
 109
 110extern struct kobject *kobject_get(struct kobject *kobj);
 111extern struct kobject * __must_check kobject_get_unless_zero(
 112                                                struct kobject *kobj);
 113extern void kobject_put(struct kobject *kobj);
 114
 115extern const void *kobject_namespace(struct kobject *kobj);
 116extern void kobject_get_ownership(struct kobject *kobj,
 117                                  kuid_t *uid, kgid_t *gid);
 118extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 119
 120/**
 121 * kobject_has_children - Returns whether a kobject has children.
 122 * @kobj: the object to test
 123 *
 124 * This will return whether a kobject has other kobjects as children.
 125 *
 126 * It does NOT account for the presence of attribute files, only sub
 127 * directories. It also assumes there is no concurrent addition or
 128 * removal of such children, and thus relies on external locking.
 129 */
 130static inline bool kobject_has_children(struct kobject *kobj)
 131{
 132        WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
 133
 134        return kobj->sd && kobj->sd->dir.subdirs;
 135}
 136
 137struct kobj_type {
 138        void (*release)(struct kobject *kobj);
 139        const struct sysfs_ops *sysfs_ops;
 140        struct attribute **default_attrs;       /* use default_groups instead */
 141        const struct attribute_group **default_groups;
 142        const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 143        const void *(*namespace)(struct kobject *kobj);
 144        void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);
 145};
 146
 147struct kobj_uevent_env {
 148        char *argv[3];
 149        char *envp[UEVENT_NUM_ENVP];
 150        int envp_idx;
 151        char buf[UEVENT_BUFFER_SIZE];
 152        int buflen;
 153};
 154
 155struct kset_uevent_ops {
 156        int (* const filter)(struct kset *kset, struct kobject *kobj);
 157        const char *(* const name)(struct kset *kset, struct kobject *kobj);
 158        int (* const uevent)(struct kset *kset, struct kobject *kobj,
 159                      struct kobj_uevent_env *env);
 160};
 161
 162struct kobj_attribute {
 163        struct attribute attr;
 164        ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 165                        char *buf);
 166        ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 167                         const char *buf, size_t count);
 168};
 169
 170extern const struct sysfs_ops kobj_sysfs_ops;
 171
 172struct sock;
 173
 174/**
 175 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 176 *
 177 * A kset defines a group of kobjects.  They can be individually
 178 * different "types" but overall these kobjects all want to be grouped
 179 * together and operated on in the same manner.  ksets are used to
 180 * define the attribute callbacks and other common events that happen to
 181 * a kobject.
 182 *
 183 * @list: the list of all kobjects for this kset
 184 * @list_lock: a lock for iterating over the kobjects
 185 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 186 * @uevent_ops: the set of uevent operations for this kset.  These are
 187 * called whenever a kobject has something happen to it so that the kset
 188 * can add new environment variables, or filter out the uevents if so
 189 * desired.
 190 */
 191struct kset {
 192        struct list_head list;
 193        spinlock_t list_lock;
 194        struct kobject kobj;
 195        const struct kset_uevent_ops *uevent_ops;
 196} __randomize_layout;
 197
 198extern void kset_init(struct kset *kset);
 199extern int __must_check kset_register(struct kset *kset);
 200extern void kset_unregister(struct kset *kset);
 201extern struct kset * __must_check kset_create_and_add(const char *name,
 202                                                const struct kset_uevent_ops *u,
 203                                                struct kobject *parent_kobj);
 204
 205static inline struct kset *to_kset(struct kobject *kobj)
 206{
 207        return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 208}
 209
 210static inline struct kset *kset_get(struct kset *k)
 211{
 212        return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 213}
 214
 215static inline void kset_put(struct kset *k)
 216{
 217        kobject_put(&k->kobj);
 218}
 219
 220static inline struct kobj_type *get_ktype(struct kobject *kobj)
 221{
 222        return kobj->ktype;
 223}
 224
 225extern struct kobject *kset_find_obj(struct kset *, const char *);
 226
 227/* The global /sys/kernel/ kobject for people to chain off of */
 228extern struct kobject *kernel_kobj;
 229/* The global /sys/kernel/mm/ kobject for people to chain off of */
 230extern struct kobject *mm_kobj;
 231/* The global /sys/hypervisor/ kobject for people to chain off of */
 232extern struct kobject *hypervisor_kobj;
 233/* The global /sys/power/ kobject for people to chain off of */
 234extern struct kobject *power_kobj;
 235/* The global /sys/firmware/ kobject for people to chain off of */
 236extern struct kobject *firmware_kobj;
 237
 238int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 239int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 240                        char *envp[]);
 241int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
 242
 243__printf(2, 3)
 244int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
 245
 246#endif /* _KOBJECT_H_ */
 247