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 */
37 extern char uevent_helper[];
38 #endif
39
40 /* counter to tag the uevent, read only except for the kobject core */
41 extern 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 */
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 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
kobject_name(const struct kobject * kobj)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 void kobject_get_ownership(struct kobject *kobj,
118 kuid_t *uid, kgid_t *gid);
119 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
120
121 /**
122 * kobject_has_children - Returns whether a kobject has children.
123 * @kobj: the object to test
124 *
125 * This will return whether a kobject has other kobjects as children.
126 *
127 * It does NOT account for the presence of attribute files, only sub
128 * directories. It also assumes there is no concurrent addition or
129 * removal of such children, and thus relies on external locking.
130 */
kobject_has_children(struct kobject * kobj)131 static inline bool kobject_has_children(struct kobject *kobj)
132 {
133 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
134
135 return kobj->sd && kobj->sd->dir.subdirs;
136 }
137
138 struct kobj_type {
139 void (*release)(struct kobject *kobj);
140 const struct sysfs_ops *sysfs_ops;
141 struct attribute **default_attrs; /* use default_groups instead */
142 const struct attribute_group **default_groups;
143 const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
144 const void *(*namespace)(struct kobject *kobj);
145 void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);
146 };
147
148 struct kobj_uevent_env {
149 char *argv[3];
150 char *envp[UEVENT_NUM_ENVP];
151 int envp_idx;
152 char buf[UEVENT_BUFFER_SIZE];
153 int buflen;
154 };
155
156 struct kset_uevent_ops {
157 int (* const filter)(struct kset *kset, struct kobject *kobj);
158 const char *(* const name)(struct kset *kset, struct kobject *kobj);
159 int (* const uevent)(struct kset *kset, struct kobject *kobj,
160 struct kobj_uevent_env *env);
161 };
162
163 struct kobj_attribute {
164 struct attribute attr;
165 ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
166 char *buf);
167 ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
168 const char *buf, size_t count);
169 };
170
171 extern const struct sysfs_ops kobj_sysfs_ops;
172
173 struct sock;
174
175 /**
176 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
177 *
178 * A kset defines a group of kobjects. They can be individually
179 * different "types" but overall these kobjects all want to be grouped
180 * together and operated on in the same manner. ksets are used to
181 * define the attribute callbacks and other common events that happen to
182 * a kobject.
183 *
184 * @list: the list of all kobjects for this kset
185 * @list_lock: a lock for iterating over the kobjects
186 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
187 * @uevent_ops: the set of uevent operations for this kset. These are
188 * called whenever a kobject has something happen to it so that the kset
189 * can add new environment variables, or filter out the uevents if so
190 * desired.
191 */
192 struct kset {
193 struct list_head list;
194 spinlock_t list_lock;
195 struct kobject kobj;
196 const struct kset_uevent_ops *uevent_ops;
197 } __randomize_layout;
198
199 extern void kset_init(struct kset *kset);
200 extern int __must_check kset_register(struct kset *kset);
201 extern void kset_unregister(struct kset *kset);
202 extern struct kset * __must_check kset_create_and_add(const char *name,
203 const struct kset_uevent_ops *u,
204 struct kobject *parent_kobj);
205
to_kset(struct kobject * kobj)206 static inline struct kset *to_kset(struct kobject *kobj)
207 {
208 return kobj ? container_of(kobj, struct kset, kobj) : NULL;
209 }
210
kset_get(struct kset * k)211 static inline struct kset *kset_get(struct kset *k)
212 {
213 return k ? to_kset(kobject_get(&k->kobj)) : NULL;
214 }
215
kset_put(struct kset * k)216 static inline void kset_put(struct kset *k)
217 {
218 kobject_put(&k->kobj);
219 }
220
get_ktype(struct kobject * kobj)221 static inline struct kobj_type *get_ktype(struct kobject *kobj)
222 {
223 return kobj->ktype;
224 }
225
226 extern struct kobject *kset_find_obj(struct kset *, const char *);
227
228 /* The global /sys/kernel/ kobject for people to chain off of */
229 extern struct kobject *kernel_kobj;
230 /* The global /sys/kernel/mm/ kobject for people to chain off of */
231 extern struct kobject *mm_kobj;
232 /* The global /sys/hypervisor/ kobject for people to chain off of */
233 extern struct kobject *hypervisor_kobj;
234 /* The global /sys/power/ kobject for people to chain off of */
235 extern struct kobject *power_kobj;
236 /* The global /sys/firmware/ kobject for people to chain off of */
237 extern struct kobject *firmware_kobj;
238
239 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
240 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
241 char *envp[]);
242 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
243
244 __printf(2, 3)
245 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
246
247 #endif /* _KOBJECT_H_ */
248