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/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 */
  37 extern char uevent_helper[];
  38 #endif
  39
  40 /* counter to tag the uevent, read only except for the kobject core */
  41 extern 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  */
  53 enum 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
  64 struct 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
  87 static inline const char *kobject_name(const struct kobject *kobj)
  88 {
  89         return kobj->name;
  90 }
  91
  92 void 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
 101 void kobject_del(struct kobject *kobj);
 102
 103 struct kobject * __must_check kobject_create_and_add(const char *name, struct kobject *parent);
 104
 105 int __must_check kobject_rename(struct kobject *, const char *new_name);
 106 int __must_check kobject_move(struct kobject *, struct kobject *);
 107
 108 struct kobject *kobject_get(struct kobject *kobj);
 109 struct kobject * __must_check kobject_get_unless_zero(struct kobject *kobj);
 110 void kobject_put(struct kobject *kobj);
 111
 112 const void *kobject_namespace(const struct kobject *kobj);
 113 void kobject_get_ownership(const struct kobject *kobj, kuid_t *uid, kgid_t *gid);
 114 char *kobject_get_path(const struct kobject *kobj, gfp_t flag);
 115
 116 struct 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
 125 struct 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
 133 struct 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
 139 struct 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
 147 extern const struct sysfs_ops kobj_sysfs_ops;
 148
 149 struct 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  */
 168 struct 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
 175 void kset_init(struct kset *kset);
 176 int __must_check kset_register(struct kset *kset);
 177 void kset_unregister(struct kset *kset);
 178 struct kset * __must_check kset_create_and_add(const char *name, const struct kset_uevent_ops *u,
 179                                                struct kobject *parent_kobj);
 180
 181 static inline struct kset *to_kset(struct kobject *kobj)
 182 {
 183         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 184 }
 185
 186 static inline struct kset *kset_get(struct kset *k)
 187 {
 188         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 189 }
 190
 191 static inline void kset_put(struct kset *k)
 192 {
 193         kobject_put(&k->kobj);
 194 }
 195
 196 static inline const struct kobj_type *get_ktype(const struct kobject *kobj)
 197 {
 198         return kobj->ktype;
 199 }
 200
 201 struct kobject *kset_find_obj(struct kset *, const char *);
 202
 203 /* The global /sys/kernel/ kobject for people to chain off of */
 204 extern struct kobject *kernel_kobj;
 205 /* The global /sys/kernel/mm/ kobject for people to chain off of */
 206 extern struct kobject *mm_kobj;
 207 /* The global /sys/hypervisor/ kobject for people to chain off of */
 208 extern struct kobject *hypervisor_kobj;
 209 /* The global /sys/power/ kobject for people to chain off of */
 210 extern struct kobject *power_kobj;
 211 /* The global /sys/firmware/ kobject for people to chain off of */
 212 extern struct kobject *firmware_kobj;
 213
 214 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 215 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 216                         char *envp[]);
 217 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
 218
 219 __printf(2, 3)
 220 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
 221
 222 #endif /* _KOBJECT_H_ */