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
  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 #ifdef CONFIG_UEVENT_HELPER
  35 /* path to the userspace helper executed on an event */
  36 extern char uevent_helper[];
  37 #endif
  38
  39 /* counter to tag the uevent, read only except for the kobject core */
  40 extern u64 uevent_seqnum;
  41
  42 /*
  43  * The actions here must match the index to the string array
  44  * in lib/kobject_uevent.c
  45  *
  46  * Do not add new actions here without checking with the driver-core
  47  * maintainers. Action strings are not meant to express subsystem
  48  * or device specific properties. In most cases you want to send a
  49  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  50  * specific variables added to the event environment.
  51  */
  52 enum kobject_action {
  53         KOBJ_ADD,
  54         KOBJ_REMOVE,
  55         KOBJ_CHANGE,
  56         KOBJ_MOVE,
  57         KOBJ_ONLINE,
  58         KOBJ_OFFLINE,
  59         KOBJ_BIND,
  60         KOBJ_UNBIND,
  61         KOBJ_MAX
  62 };
  63
  64 struct 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
  82 extern __printf(2, 3)
  83 int kobject_set_name(struct kobject *kobj, const char *name, ...);
  84 extern __printf(2, 0)
  85 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
  86                            va_list vargs);
  87
  88 static inline const char *kobject_name(const struct kobject *kobj)
  89 {
  90         return kobj->name;
  91 }
  92
  93 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
  94 extern __printf(3, 4) __must_check
  95 int kobject_add(struct kobject *kobj, struct kobject *parent,
  96                 const char *fmt, ...);
  97 extern __printf(4, 5) __must_check
  98 int kobject_init_and_add(struct kobject *kobj,
  99                          struct kobj_type *ktype, struct kobject *parent,
 100                          const char *fmt, ...);
 101
 102 extern void kobject_del(struct kobject *kobj);
 103
 104 extern struct kobject * __must_check kobject_create(void);
 105 extern struct kobject * __must_check kobject_create_and_add(const char *name,
 106                                                 struct kobject *parent);
 107
 108 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
 109 extern int __must_check kobject_move(struct kobject *, struct kobject *);
 110
 111 extern struct kobject *kobject_get(struct kobject *kobj);
 112 extern struct kobject * __must_check kobject_get_unless_zero(
 113                                                 struct kobject *kobj);
 114 extern void kobject_put(struct kobject *kobj);
 115
 116 extern const void *kobject_namespace(struct kobject *kobj);
 117 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
 118
 119 struct kobj_type {
 120         void (*release)(struct kobject *kobj);
 121         const struct sysfs_ops *sysfs_ops;
 122         struct attribute **default_attrs;
 123         const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
 124         const void *(*namespace)(struct kobject *kobj);
 125 };
 126
 127 struct kobj_uevent_env {
 128         char *argv[3];
 129         char *envp[UEVENT_NUM_ENVP];
 130         int envp_idx;
 131         char buf[UEVENT_BUFFER_SIZE];
 132         int buflen;
 133 };
 134
 135 struct kset_uevent_ops {
 136         int (* const filter)(struct kset *kset, struct kobject *kobj);
 137         const char *(* const name)(struct kset *kset, struct kobject *kobj);
 138         int (* const uevent)(struct kset *kset, struct kobject *kobj,
 139                       struct kobj_uevent_env *env);
 140 };
 141
 142 struct kobj_attribute {
 143         struct attribute attr;
 144         ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
 145                         char *buf);
 146         ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
 147                          const char *buf, size_t count);
 148 };
 149
 150 extern const struct sysfs_ops kobj_sysfs_ops;
 151
 152 struct sock;
 153
 154 /**
 155  * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
 156  *
 157  * A kset defines a group of kobjects.  They can be individually
 158  * different "types" but overall these kobjects all want to be grouped
 159  * together and operated on in the same manner.  ksets are used to
 160  * define the attribute callbacks and other common events that happen to
 161  * a kobject.
 162  *
 163  * @list: the list of all kobjects for this kset
 164  * @list_lock: a lock for iterating over the kobjects
 165  * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
 166  * @uevent_ops: the set of uevent operations for this kset.  These are
 167  * called whenever a kobject has something happen to it so that the kset
 168  * can add new environment variables, or filter out the uevents if so
 169  * desired.
 170  */
 171 struct kset {
 172         struct list_head list;
 173         spinlock_t list_lock;
 174         struct kobject kobj;
 175         const struct kset_uevent_ops *uevent_ops;
 176 } __randomize_layout;
 177
 178 extern void kset_init(struct kset *kset);
 179 extern int __must_check kset_register(struct kset *kset);
 180 extern void kset_unregister(struct kset *kset);
 181 extern struct kset * __must_check kset_create_and_add(const char *name,
 182                                                 const struct kset_uevent_ops *u,
 183                                                 struct kobject *parent_kobj);
 184
 185 static inline struct kset *to_kset(struct kobject *kobj)
 186 {
 187         return kobj ? container_of(kobj, struct kset, kobj) : NULL;
 188 }
 189
 190 static inline struct kset *kset_get(struct kset *k)
 191 {
 192         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 193 }
 194
 195 static inline void kset_put(struct kset *k)
 196 {
 197         kobject_put(&k->kobj);
 198 }
 199
 200 static inline struct kobj_type *get_ktype(struct kobject *kobj)
 201 {
 202         return kobj->ktype;
 203 }
 204
 205 extern struct kobject *kset_find_obj(struct kset *, const char *);
 206
 207 /* The global /sys/kernel/ kobject for people to chain off of */
 208 extern struct kobject *kernel_kobj;
 209 /* The global /sys/kernel/mm/ kobject for people to chain off of */
 210 extern struct kobject *mm_kobj;
 211 /* The global /sys/hypervisor/ kobject for people to chain off of */
 212 extern struct kobject *hypervisor_kobj;
 213 /* The global /sys/power/ kobject for people to chain off of */
 214 extern struct kobject *power_kobj;
 215 /* The global /sys/firmware/ kobject for people to chain off of */
 216 extern struct kobject *firmware_kobj;
 217
 218 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 219 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 220                         char *envp[]);
 221 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
 222
 223 __printf(2, 3)
 224 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
 225
 226 #endif /* _KOBJECT_H_ */