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/kobject.txt 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                 32      /* 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        KOBJ_MAX
  63};
  64
  65struct kobject {
  66        const char              *name;
  67        struct list_head        entry;
  68        struct kobject          *parent;
  69        struct kset             *kset;
  70        struct kobj_type        *ktype;
  71        struct kernfs_node      *sd; /* sysfs directory entry */
  72        struct kref             kref;
  73#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
  74        struct delayed_work     release;
  75#endif
  76        unsigned int state_initialized:1;
  77        unsigned int state_in_sysfs:1;
  78        unsigned int state_add_uevent_sent:1;
  79        unsigned int state_remove_uevent_sent:1;
  80        unsigned int uevent_suppress:1;
  81};
  82
  83extern __printf(2, 3)
  84int kobject_set_name(struct kobject *kobj, const char *name, ...);
  85extern __printf(2, 0)
  86int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
  87                           va_list vargs);
  88
  89static inline const char *kobject_name(const struct kobject *kobj)
  90{
  91        return kobj->name;
  92}
  93
  94extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  95extern __printf(3, 4) __must_check
  96int kobject_add(struct kobject *kobj, struct kobject *parent,
  97                const char *fmt, ...);
  98extern __printf(4, 5) __must_check
  99int kobject_init_and_add(struct kobject *kobj,
 100                         struct kobj_type *ktype, struct kobject *parent,
 101                         const char *fmt, ...);
 102
 103extern void kobject_del(struct kobject *kobj);
 104
 105extern struct kobject * __must_check kobject_create(void);
 106extern struct kobject * __must_check kobject_create_and_add(const char *name,
 107                                                struct kobject *parent);
 108
 109extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 110extern int __must_check kobject_move(struct kobject *, struct kobject *);
 111
 112extern struct kobject *kobject_get(struct kobject *kobj);
 113extern struct kobject * __must_check kobject_get_unless_zero(
 114                                                struct kobject *kobj);
 115extern void kobject_put(struct kobject *kobj);
 116
 117extern const void *kobject_namespace(struct kobject *kobj);
 118extern void kobject_get_ownership(struct kobject *kobj,
 119                                  kuid_t *uid, kgid_t *gid);
 120extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 121
 122/**
 123 * kobject_has_children - Returns whether a kobject has children.
 124 * @kobj: the object to test
 125 *
 126 * This will return whether a kobject has other kobjects as children.
 127 *
 128 * It does NOT account for the presence of attribute files, only sub
 129 * directories. It also assumes there is no concurrent addition or
 130 * removal of such children, and thus relies on external locking.
 131 */
 132static inline bool kobject_has_children(struct kobject *kobj)
 133{
 134        WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
 135
 136        return kobj->sd && kobj->sd->dir.subdirs;
 137}
 138
 139struct kobj_type {
 140        void (*release)(struct kobject *kobj);
 141        const struct sysfs_ops *sysfs_ops;
 142        struct attribute **default_attrs;       /* use default_groups instead */
 143        const struct attribute_group **default_groups;
 144        const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 145        const void *(*namespace)(struct kobject *kobj);
 146        void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);
 147};
 148
 149struct kobj_uevent_env {
 150        char *argv[3];
 151        char *envp[UEVENT_NUM_ENVP];
 152        int envp_idx;
 153        char buf[UEVENT_BUFFER_SIZE];
 154        int buflen;
 155};
 156
 157struct kset_uevent_ops {
 158        int (* const filter)(struct kset *kset, struct kobject *kobj);
 159        const char *(* const name)(struct kset *kset, struct kobject *kobj);
 160        int (* const uevent)(struct kset *kset, struct kobject *kobj,
 161                      struct kobj_uevent_env *env);
 162};
 163
 164struct kobj_attribute {
 165        struct attribute attr;
 166        ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 167                        char *buf);
 168        ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 169                         const char *buf, size_t count);
 170};
 171
 172extern const struct sysfs_ops kobj_sysfs_ops;
 173
 174struct sock;
 175
 176/**
 177 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 178 *
 179 * A kset defines a group of kobjects.  They can be individually
 180 * different "types" but overall these kobjects all want to be grouped
 181 * together and operated on in the same manner.  ksets are used to
 182 * define the attribute callbacks and other common events that happen to
 183 * a kobject.
 184 *
 185 * @list: the list of all kobjects for this kset
 186 * @list_lock: a lock for iterating over the kobjects
 187 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 188 * @uevent_ops: the set of uevent operations for this kset.  These are
 189 * called whenever a kobject has something happen to it so that the kset
 190 * can add new environment variables, or filter out the uevents if so
 191 * desired.
 192 */
 193struct kset {
 194        struct list_head list;
 195        spinlock_t list_lock;
 196        struct kobject kobj;
 197        const struct kset_uevent_ops *uevent_ops;
 198} __randomize_layout;
 199
 200extern void kset_init(struct kset *kset);
 201extern int __must_check kset_register(struct kset *kset);
 202extern void kset_unregister(struct kset *kset);
 203extern struct kset * __must_check kset_create_and_add(const char *name,
 204                                                const struct kset_uevent_ops *u,
 205                                                struct kobject *parent_kobj);
 206
 207static inline struct kset *to_kset(struct kobject *kobj)
 208{
 209        return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 210}
 211
 212static inline struct kset *kset_get(struct kset *k)
 213{
 214        return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 215}
 216
 217static inline void kset_put(struct kset *k)
 218{
 219        kobject_put(&k->kobj);
 220}
 221
 222static inline struct kobj_type *get_ktype(struct kobject *kobj)
 223{
 224        return kobj->ktype;
 225}
 226
 227extern struct kobject *kset_find_obj(struct kset *, const char *);
 228
 229/* The global /sys/kernel/ kobject for people to chain off of */
 230extern struct kobject *kernel_kobj;
 231/* The global /sys/kernel/mm/ kobject for people to chain off of */
 232extern struct kobject *mm_kobj;
 233/* The global /sys/hypervisor/ kobject for people to chain off of */
 234extern struct kobject *hypervisor_kobj;
 235/* The global /sys/power/ kobject for people to chain off of */
 236extern struct kobject *power_kobj;
 237/* The global /sys/firmware/ kobject for people to chain off of */
 238extern struct kobject *firmware_kobj;
 239
 240int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 241int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 242                        char *envp[]);
 243int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
 244
 245__printf(2, 3)
 246int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
 247
 248#endif /* _KOBJECT_H_ */
 249