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 #include <linux/android_kabi.h>
31
32 #define UEVENT_HELPER_PATH_LEN 256
33 #define UEVENT_NUM_ENVP 64 /* number of env pointers */
34 #define UEVENT_BUFFER_SIZE 2048 /* buffer for the variables */
35
36 #ifdef CONFIG_UEVENT_HELPER
37 /* path to the userspace helper executed on an event */
38 extern char uevent_helper[];
39 #endif
40
41 /* counter to tag the uevent, read only except for the kobject core */
42 extern u64 uevent_seqnum;
43
44 /*
45 * The actions here must match the index to the string array
46 * in lib/kobject_uevent.c
47 *
48 * Do not add new actions here without checking with the driver-core
49 * maintainers. Action strings are not meant to express subsystem
50 * or device specific properties. In most cases you want to send a
51 * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
52 * specific variables added to the event environment.
53 */
54 enum kobject_action {
55 KOBJ_ADD,
56 KOBJ_REMOVE,
57 KOBJ_CHANGE,
58 KOBJ_MOVE,
59 KOBJ_ONLINE,
60 KOBJ_OFFLINE,
61 KOBJ_BIND,
62 KOBJ_UNBIND,
63 };
64
65 struct 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 ANDROID_KABI_RESERVE(1);
83 ANDROID_KABI_RESERVE(2);
84 ANDROID_KABI_RESERVE(3);
85 ANDROID_KABI_RESERVE(4);
86 };
87
88 extern __printf(2, 3)
89 int kobject_set_name(struct kobject *kobj, const char *name, ...);
90 extern __printf(2, 0)
91 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
92 va_list vargs);
93
kobject_name(const struct kobject * kobj)94 static inline const char *kobject_name(const struct kobject *kobj)
95 {
96 return kobj->name;
97 }
98
99 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
100 extern __printf(3, 4) __must_check
101 int kobject_add(struct kobject *kobj, struct kobject *parent,
102 const char *fmt, ...);
103 extern __printf(4, 5) __must_check
104 int kobject_init_and_add(struct kobject *kobj,
105 struct kobj_type *ktype, struct kobject *parent,
106 const char *fmt, ...);
107
108 extern void kobject_del(struct kobject *kobj);
109
110 extern struct kobject * __must_check kobject_create(void);
111 extern struct kobject * __must_check kobject_create_and_add(const char *name,
112 struct kobject *parent);
113
114 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
115 extern int __must_check kobject_move(struct kobject *, struct kobject *);
116
117 extern struct kobject *kobject_get(struct kobject *kobj);
118 extern struct kobject * __must_check kobject_get_unless_zero(
119 struct kobject *kobj);
120 extern void kobject_put(struct kobject *kobj);
121
122 extern const void *kobject_namespace(struct kobject *kobj);
123 extern void kobject_get_ownership(struct kobject *kobj,
124 kuid_t *uid, kgid_t *gid);
125 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
126
127 /**
128 * kobject_has_children - Returns whether a kobject has children.
129 * @kobj: the object to test
130 *
131 * This will return whether a kobject has other kobjects as children.
132 *
133 * It does NOT account for the presence of attribute files, only sub
134 * directories. It also assumes there is no concurrent addition or
135 * removal of such children, and thus relies on external locking.
136 */
kobject_has_children(struct kobject * kobj)137 static inline bool kobject_has_children(struct kobject *kobj)
138 {
139 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
140
141 return kobj->sd && kobj->sd->dir.subdirs;
142 }
143
144 struct kobj_type {
145 void (*release)(struct kobject *kobj);
146 const struct sysfs_ops *sysfs_ops;
147 struct attribute **default_attrs; /* use default_groups instead */
148 const struct attribute_group **default_groups;
149 const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
150 const void *(*namespace)(struct kobject *kobj);
151 void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);
152
153 ANDROID_KABI_RESERVE(1);
154 ANDROID_KABI_RESERVE(2);
155 ANDROID_KABI_RESERVE(3);
156 ANDROID_KABI_RESERVE(4);
157 };
158
159 struct kobj_uevent_env {
160 char *argv[3];
161 char *envp[UEVENT_NUM_ENVP];
162 int envp_idx;
163 char buf[UEVENT_BUFFER_SIZE];
164 int buflen;
165 };
166
167 struct kset_uevent_ops {
168 int (* const filter)(struct kset *kset, struct kobject *kobj);
169 const char *(* const name)(struct kset *kset, struct kobject *kobj);
170 int (* const uevent)(struct kset *kset, struct kobject *kobj,
171 struct kobj_uevent_env *env);
172 };
173
174 struct kobj_attribute {
175 struct attribute attr;
176 ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
177 char *buf);
178 ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
179 const char *buf, size_t count);
180 };
181
182 extern const struct sysfs_ops kobj_sysfs_ops;
183
184 struct sock;
185
186 /**
187 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
188 *
189 * A kset defines a group of kobjects. They can be individually
190 * different "types" but overall these kobjects all want to be grouped
191 * together and operated on in the same manner. ksets are used to
192 * define the attribute callbacks and other common events that happen to
193 * a kobject.
194 *
195 * @list: the list of all kobjects for this kset
196 * @list_lock: a lock for iterating over the kobjects
197 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
198 * @uevent_ops: the set of uevent operations for this kset. These are
199 * called whenever a kobject has something happen to it so that the kset
200 * can add new environment variables, or filter out the uevents if so
201 * desired.
202 */
203 struct kset {
204 struct list_head list;
205 spinlock_t list_lock;
206 struct kobject kobj;
207 const struct kset_uevent_ops *uevent_ops;
208
209 ANDROID_KABI_RESERVE(1);
210 ANDROID_KABI_RESERVE(2);
211 ANDROID_KABI_RESERVE(3);
212 ANDROID_KABI_RESERVE(4);
213 } __randomize_layout;
214
215 extern void kset_init(struct kset *kset);
216 extern int __must_check kset_register(struct kset *kset);
217 extern void kset_unregister(struct kset *kset);
218 extern struct kset * __must_check kset_create_and_add(const char *name,
219 const struct kset_uevent_ops *u,
220 struct kobject *parent_kobj);
221
to_kset(struct kobject * kobj)222 static inline struct kset *to_kset(struct kobject *kobj)
223 {
224 return kobj ? container_of(kobj, struct kset, kobj) : NULL;
225 }
226
kset_get(struct kset * k)227 static inline struct kset *kset_get(struct kset *k)
228 {
229 return k ? to_kset(kobject_get(&k->kobj)) : NULL;
230 }
231
kset_put(struct kset * k)232 static inline void kset_put(struct kset *k)
233 {
234 kobject_put(&k->kobj);
235 }
236
get_ktype(struct kobject * kobj)237 static inline struct kobj_type *get_ktype(struct kobject *kobj)
238 {
239 return kobj->ktype;
240 }
241
242 extern struct kobject *kset_find_obj(struct kset *, const char *);
243
244 /* The global /sys/kernel/ kobject for people to chain off of */
245 extern struct kobject *kernel_kobj;
246 /* The global /sys/kernel/mm/ kobject for people to chain off of */
247 extern struct kobject *mm_kobj;
248 /* The global /sys/hypervisor/ kobject for people to chain off of */
249 extern struct kobject *hypervisor_kobj;
250 /* The global /sys/power/ kobject for people to chain off of */
251 extern struct kobject *power_kobj;
252 /* The global /sys/firmware/ kobject for people to chain off of */
253 extern struct kobject *firmware_kobj;
254
255 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
256 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
257 char *envp[]);
258 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
259
260 __printf(2, 3)
261 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
262
263 #endif /* _KOBJECT_H_ */
264