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