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 #include <linux/android_kabi.h>
31
32 #define UEVENT_HELPER_PATH_LEN 256
33 #define UEVENT_NUM_ENVP 32 /* 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 KOBJ_MAX
64 };
65
66 struct kobject {
67 const char *name;
68 struct list_head entry;
69 struct kobject *parent;
70 struct kset *kset;
71 struct kobj_type *ktype;
72 struct kernfs_node *sd; /* sysfs directory entry */
73 struct kref kref;
74 #ifdef CONFIG_DEBUG_KOBJECT_RELEASE
75 struct delayed_work release;
76 #endif
77 unsigned int state_initialized:1;
78 unsigned int state_in_sysfs:1;
79 unsigned int state_add_uevent_sent:1;
80 unsigned int state_remove_uevent_sent:1;
81 unsigned int uevent_suppress:1;
82
83 ANDROID_KABI_RESERVE(1);
84 ANDROID_KABI_RESERVE(2);
85 ANDROID_KABI_RESERVE(3);
86 ANDROID_KABI_RESERVE(4);
87 };
88
89 extern __printf(2, 3)
90 int kobject_set_name(struct kobject *kobj, const char *name, ...);
91 extern __printf(2, 0)
92 int kobject_set_name_vargs(struct kobject *kobj, const char *fmt,
93 va_list vargs);
94
kobject_name(const struct kobject * kobj)95 static inline const char *kobject_name(const struct kobject *kobj)
96 {
97 return kobj->name;
98 }
99
100 extern void kobject_init(struct kobject *kobj, struct kobj_type *ktype);
101 extern __printf(3, 4) __must_check
102 int kobject_add(struct kobject *kobj, struct kobject *parent,
103 const char *fmt, ...);
104 extern __printf(4, 5) __must_check
105 int kobject_init_and_add(struct kobject *kobj,
106 struct kobj_type *ktype, struct kobject *parent,
107 const char *fmt, ...);
108
109 extern void kobject_del(struct kobject *kobj);
110
111 extern struct kobject * __must_check kobject_create(void);
112 extern struct kobject * __must_check kobject_create_and_add(const char *name,
113 struct kobject *parent);
114
115 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
116 extern int __must_check kobject_move(struct kobject *, struct kobject *);
117
118 extern struct kobject *kobject_get(struct kobject *kobj);
119 extern struct kobject * __must_check kobject_get_unless_zero(
120 struct kobject *kobj);
121 extern void kobject_put(struct kobject *kobj);
122
123 extern const void *kobject_namespace(struct kobject *kobj);
124 extern void kobject_get_ownership(struct kobject *kobj,
125 kuid_t *uid, kgid_t *gid);
126 extern char *kobject_get_path(struct kobject *kobj, gfp_t flag);
127
128 /**
129 * kobject_has_children - Returns whether a kobject has children.
130 * @kobj: the object to test
131 *
132 * This will return whether a kobject has other kobjects as children.
133 *
134 * It does NOT account for the presence of attribute files, only sub
135 * directories. It also assumes there is no concurrent addition or
136 * removal of such children, and thus relies on external locking.
137 */
kobject_has_children(struct kobject * kobj)138 static inline bool kobject_has_children(struct kobject *kobj)
139 {
140 WARN_ON_ONCE(kref_read(&kobj->kref) == 0);
141
142 return kobj->sd && kobj->sd->dir.subdirs;
143 }
144
145 struct kobj_type {
146 void (*release)(struct kobject *kobj);
147 const struct sysfs_ops *sysfs_ops;
148 struct attribute **default_attrs; /* use default_groups instead */
149 const struct attribute_group **default_groups;
150 const struct kobj_ns_type_operations *(*child_ns_type)(struct kobject *kobj);
151 const void *(*namespace)(struct kobject *kobj);
152 void (*get_ownership)(struct kobject *kobj, kuid_t *uid, kgid_t *gid);
153
154 ANDROID_KABI_RESERVE(1);
155 ANDROID_KABI_RESERVE(2);
156 ANDROID_KABI_RESERVE(3);
157 ANDROID_KABI_RESERVE(4);
158 };
159
160 struct kobj_uevent_env {
161 char *argv[3];
162 char *envp[UEVENT_NUM_ENVP];
163 int envp_idx;
164 char buf[UEVENT_BUFFER_SIZE];
165 int buflen;
166 };
167
168 struct kset_uevent_ops {
169 int (* const filter)(struct kset *kset, struct kobject *kobj);
170 const char *(* const name)(struct kset *kset, struct kobject *kobj);
171 int (* const uevent)(struct kset *kset, struct kobject *kobj,
172 struct kobj_uevent_env *env);
173 };
174
175 struct kobj_attribute {
176 struct attribute attr;
177 ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr,
178 char *buf);
179 ssize_t (*store)(struct kobject *kobj, struct kobj_attribute *attr,
180 const char *buf, size_t count);
181 };
182
183 extern const struct sysfs_ops kobj_sysfs_ops;
184
185 struct sock;
186
187 /**
188 * struct kset - a set of kobjects of a specific type, belonging to a specific subsystem.
189 *
190 * A kset defines a group of kobjects. They can be individually
191 * different "types" but overall these kobjects all want to be grouped
192 * together and operated on in the same manner. ksets are used to
193 * define the attribute callbacks and other common events that happen to
194 * a kobject.
195 *
196 * @list: the list of all kobjects for this kset
197 * @list_lock: a lock for iterating over the kobjects
198 * @kobj: the embedded kobject for this kset (recursion, isn't it fun...)
199 * @uevent_ops: the set of uevent operations for this kset. These are
200 * called whenever a kobject has something happen to it so that the kset
201 * can add new environment variables, or filter out the uevents if so
202 * desired.
203 */
204 struct kset {
205 struct list_head list;
206 spinlock_t list_lock;
207 struct kobject kobj;
208 const struct kset_uevent_ops *uevent_ops;
209
210 ANDROID_KABI_RESERVE(1);
211 ANDROID_KABI_RESERVE(2);
212 ANDROID_KABI_RESERVE(3);
213 ANDROID_KABI_RESERVE(4);
214 } __randomize_layout;
215
216 extern void kset_init(struct kset *kset);
217 extern int __must_check kset_register(struct kset *kset);
218 extern void kset_unregister(struct kset *kset);
219 extern struct kset * __must_check kset_create_and_add(const char *name,
220 const struct kset_uevent_ops *u,
221 struct kobject *parent_kobj);
222
to_kset(struct kobject * kobj)223 static inline struct kset *to_kset(struct kobject *kobj)
224 {
225 return kobj ? container_of(kobj, struct kset, kobj) : NULL;
226 }
227
kset_get(struct kset * k)228 static inline struct kset *kset_get(struct kset *k)
229 {
230 return k ? to_kset(kobject_get(&k->kobj)) : NULL;
231 }
232
kset_put(struct kset * k)233 static inline void kset_put(struct kset *k)
234 {
235 kobject_put(&k->kobj);
236 }
237
get_ktype(struct kobject * kobj)238 static inline struct kobj_type *get_ktype(struct kobject *kobj)
239 {
240 return kobj->ktype;
241 }
242
243 extern struct kobject *kset_find_obj(struct kset *, const char *);
244
245 /* The global /sys/kernel/ kobject for people to chain off of */
246 extern struct kobject *kernel_kobj;
247 /* The global /sys/kernel/mm/ kobject for people to chain off of */
248 extern struct kobject *mm_kobj;
249 /* The global /sys/hypervisor/ kobject for people to chain off of */
250 extern struct kobject *hypervisor_kobj;
251 /* The global /sys/power/ kobject for people to chain off of */
252 extern struct kobject *power_kobj;
253 /* The global /sys/firmware/ kobject for people to chain off of */
254 extern struct kobject *firmware_kobj;
255
256 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
257 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
258 char *envp[]);
259 int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count);
260
261 __printf(2, 3)
262 int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...);
263
264 #endif /* _KOBJECT_H_ */
265