sysfs: Add support for permanently empty directories to serve as mount points.
[deliverable/linux.git] / include / linux / sysfs.h
1 /*
2 * sysfs.h - definitions for the device driver filesystem
3 *
4 * Copyright (c) 2001,2002 Patrick Mochel
5 * Copyright (c) 2004 Silicon Graphics, Inc.
6 * Copyright (c) 2007 SUSE Linux Products GmbH
7 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
8 *
9 * Please see Documentation/filesystems/sysfs.txt for more information.
10 */
11
12 #ifndef _SYSFS_H_
13 #define _SYSFS_H_
14
15 #include <linux/kernfs.h>
16 #include <linux/compiler.h>
17 #include <linux/errno.h>
18 #include <linux/list.h>
19 #include <linux/lockdep.h>
20 #include <linux/kobject_ns.h>
21 #include <linux/stat.h>
22 #include <linux/atomic.h>
23
24 struct kobject;
25 struct module;
26 struct bin_attribute;
27 enum kobj_ns_type;
28
29 struct attribute {
30 const char *name;
31 umode_t mode;
32 #ifdef CONFIG_DEBUG_LOCK_ALLOC
33 bool ignore_lockdep:1;
34 struct lock_class_key *key;
35 struct lock_class_key skey;
36 #endif
37 };
38
39 /**
40 * sysfs_attr_init - initialize a dynamically allocated sysfs attribute
41 * @attr: struct attribute to initialize
42 *
43 * Initialize a dynamically allocated struct attribute so we can
44 * make lockdep happy. This is a new requirement for attributes
45 * and initially this is only needed when lockdep is enabled.
46 * Lockdep gives a nice error when your attribute is added to
47 * sysfs if you don't have this.
48 */
49 #ifdef CONFIG_DEBUG_LOCK_ALLOC
50 #define sysfs_attr_init(attr) \
51 do { \
52 static struct lock_class_key __key; \
53 \
54 (attr)->key = &__key; \
55 } while (0)
56 #else
57 #define sysfs_attr_init(attr) do {} while (0)
58 #endif
59
60 /**
61 * struct attribute_group - data structure used to declare an attribute group.
62 * @name: Optional: Attribute group name
63 * If specified, the attribute group will be created in
64 * a new subdirectory with this name.
65 * @is_visible: Optional: Function to return permissions associated with an
66 * attribute of the group. Will be called repeatedly for each
67 * attribute in the group. Only read/write permissions as well as
68 * SYSFS_PREALLOC are accepted. Must return 0 if an attribute is
69 * not visible. The returned value will replace static permissions
70 * defined in struct attribute or struct bin_attribute.
71 * @attrs: Pointer to NULL terminated list of attributes.
72 * @bin_attrs: Pointer to NULL terminated list of binary attributes.
73 * Either attrs or bin_attrs or both must be provided.
74 */
75 struct attribute_group {
76 const char *name;
77 umode_t (*is_visible)(struct kobject *,
78 struct attribute *, int);
79 struct attribute **attrs;
80 struct bin_attribute **bin_attrs;
81 };
82
83 /**
84 * Use these macros to make defining attributes easier. See include/linux/device.h
85 * for examples..
86 */
87
88 #define SYSFS_PREALLOC 010000
89
90 #define __ATTR(_name, _mode, _show, _store) { \
91 .attr = {.name = __stringify(_name), \
92 .mode = VERIFY_OCTAL_PERMISSIONS(_mode) }, \
93 .show = _show, \
94 .store = _store, \
95 }
96
97 #define __ATTR_PREALLOC(_name, _mode, _show, _store) { \
98 .attr = {.name = __stringify(_name), \
99 .mode = SYSFS_PREALLOC | VERIFY_OCTAL_PERMISSIONS(_mode) },\
100 .show = _show, \
101 .store = _store, \
102 }
103
104 #define __ATTR_RO(_name) { \
105 .attr = { .name = __stringify(_name), .mode = S_IRUGO }, \
106 .show = _name##_show, \
107 }
108
109 #define __ATTR_WO(_name) { \
110 .attr = { .name = __stringify(_name), .mode = S_IWUSR }, \
111 .store = _name##_store, \
112 }
113
114 #define __ATTR_RW(_name) __ATTR(_name, (S_IWUSR | S_IRUGO), \
115 _name##_show, _name##_store)
116
117 #define __ATTR_NULL { .attr = { .name = NULL } }
118
119 #ifdef CONFIG_DEBUG_LOCK_ALLOC
120 #define __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) { \
121 .attr = {.name = __stringify(_name), .mode = _mode, \
122 .ignore_lockdep = true }, \
123 .show = _show, \
124 .store = _store, \
125 }
126 #else
127 #define __ATTR_IGNORE_LOCKDEP __ATTR
128 #endif
129
130 #define __ATTRIBUTE_GROUPS(_name) \
131 static const struct attribute_group *_name##_groups[] = { \
132 &_name##_group, \
133 NULL, \
134 }
135
136 #define ATTRIBUTE_GROUPS(_name) \
137 static const struct attribute_group _name##_group = { \
138 .attrs = _name##_attrs, \
139 }; \
140 __ATTRIBUTE_GROUPS(_name)
141
142 struct file;
143 struct vm_area_struct;
144
145 struct bin_attribute {
146 struct attribute attr;
147 size_t size;
148 void *private;
149 ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *,
150 char *, loff_t, size_t);
151 ssize_t (*write)(struct file *, struct kobject *, struct bin_attribute *,
152 char *, loff_t, size_t);
153 int (*mmap)(struct file *, struct kobject *, struct bin_attribute *attr,
154 struct vm_area_struct *vma);
155 };
156
157 /**
158 * sysfs_bin_attr_init - initialize a dynamically allocated bin_attribute
159 * @attr: struct bin_attribute to initialize
160 *
161 * Initialize a dynamically allocated struct bin_attribute so we
162 * can make lockdep happy. This is a new requirement for
163 * attributes and initially this is only needed when lockdep is
164 * enabled. Lockdep gives a nice error when your attribute is
165 * added to sysfs if you don't have this.
166 */
167 #define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&(bin_attr)->attr)
168
169 /* macros to create static binary attributes easier */
170 #define __BIN_ATTR(_name, _mode, _read, _write, _size) { \
171 .attr = { .name = __stringify(_name), .mode = _mode }, \
172 .read = _read, \
173 .write = _write, \
174 .size = _size, \
175 }
176
177 #define __BIN_ATTR_RO(_name, _size) { \
178 .attr = { .name = __stringify(_name), .mode = S_IRUGO }, \
179 .read = _name##_read, \
180 .size = _size, \
181 }
182
183 #define __BIN_ATTR_RW(_name, _size) __BIN_ATTR(_name, \
184 (S_IWUSR | S_IRUGO), _name##_read, \
185 _name##_write, _size)
186
187 #define __BIN_ATTR_NULL __ATTR_NULL
188
189 #define BIN_ATTR(_name, _mode, _read, _write, _size) \
190 struct bin_attribute bin_attr_##_name = __BIN_ATTR(_name, _mode, _read, \
191 _write, _size)
192
193 #define BIN_ATTR_RO(_name, _size) \
194 struct bin_attribute bin_attr_##_name = __BIN_ATTR_RO(_name, _size)
195
196 #define BIN_ATTR_RW(_name, _size) \
197 struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
198
199 struct sysfs_ops {
200 ssize_t (*show)(struct kobject *, struct attribute *, char *);
201 ssize_t (*store)(struct kobject *, struct attribute *, const char *, size_t);
202 };
203
204 #ifdef CONFIG_SYSFS
205
206 int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns);
207 void sysfs_remove_dir(struct kobject *kobj);
208 int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
209 const void *new_ns);
210 int __must_check sysfs_move_dir_ns(struct kobject *kobj,
211 struct kobject *new_parent_kobj,
212 const void *new_ns);
213 int __must_check sysfs_create_mount_point(struct kobject *parent_kobj,
214 const char *name);
215 void sysfs_remove_mount_point(struct kobject *parent_kobj,
216 const char *name);
217
218 int __must_check sysfs_create_file_ns(struct kobject *kobj,
219 const struct attribute *attr,
220 const void *ns);
221 int __must_check sysfs_create_files(struct kobject *kobj,
222 const struct attribute **attr);
223 int __must_check sysfs_chmod_file(struct kobject *kobj,
224 const struct attribute *attr, umode_t mode);
225 void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
226 const void *ns);
227 bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr);
228 void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr);
229
230 int __must_check sysfs_create_bin_file(struct kobject *kobj,
231 const struct bin_attribute *attr);
232 void sysfs_remove_bin_file(struct kobject *kobj,
233 const struct bin_attribute *attr);
234
235 int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
236 const char *name);
237 int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
238 struct kobject *target,
239 const char *name);
240 void sysfs_remove_link(struct kobject *kobj, const char *name);
241
242 int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *target,
243 const char *old_name, const char *new_name,
244 const void *new_ns);
245
246 void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
247 const char *name);
248
249 int __must_check sysfs_create_group(struct kobject *kobj,
250 const struct attribute_group *grp);
251 int __must_check sysfs_create_groups(struct kobject *kobj,
252 const struct attribute_group **groups);
253 int sysfs_update_group(struct kobject *kobj,
254 const struct attribute_group *grp);
255 void sysfs_remove_group(struct kobject *kobj,
256 const struct attribute_group *grp);
257 void sysfs_remove_groups(struct kobject *kobj,
258 const struct attribute_group **groups);
259 int sysfs_add_file_to_group(struct kobject *kobj,
260 const struct attribute *attr, const char *group);
261 void sysfs_remove_file_from_group(struct kobject *kobj,
262 const struct attribute *attr, const char *group);
263 int sysfs_merge_group(struct kobject *kobj,
264 const struct attribute_group *grp);
265 void sysfs_unmerge_group(struct kobject *kobj,
266 const struct attribute_group *grp);
267 int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
268 struct kobject *target, const char *link_name);
269 void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
270 const char *link_name);
271
272 void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
273
274 int __must_check sysfs_init(void);
275
276 static inline void sysfs_enable_ns(struct kernfs_node *kn)
277 {
278 return kernfs_enable_ns(kn);
279 }
280
281 #else /* CONFIG_SYSFS */
282
283 static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
284 {
285 return 0;
286 }
287
288 static inline void sysfs_remove_dir(struct kobject *kobj)
289 {
290 }
291
292 static inline int sysfs_rename_dir_ns(struct kobject *kobj,
293 const char *new_name, const void *new_ns)
294 {
295 return 0;
296 }
297
298 static inline int sysfs_move_dir_ns(struct kobject *kobj,
299 struct kobject *new_parent_kobj,
300 const void *new_ns)
301 {
302 return 0;
303 }
304
305 static inline int sysfs_create_mount_point(struct kobject *parent_kobj,
306 const char *name)
307 {
308 return 0;
309 }
310
311 static inline void sysfs_remove_mount_point(struct kobject *parent_kobj,
312 const char *name)
313 {
314 }
315
316 static inline int sysfs_create_file_ns(struct kobject *kobj,
317 const struct attribute *attr,
318 const void *ns)
319 {
320 return 0;
321 }
322
323 static inline int sysfs_create_files(struct kobject *kobj,
324 const struct attribute **attr)
325 {
326 return 0;
327 }
328
329 static inline int sysfs_chmod_file(struct kobject *kobj,
330 const struct attribute *attr, umode_t mode)
331 {
332 return 0;
333 }
334
335 static inline void sysfs_remove_file_ns(struct kobject *kobj,
336 const struct attribute *attr,
337 const void *ns)
338 {
339 }
340
341 static inline bool sysfs_remove_file_self(struct kobject *kobj,
342 const struct attribute *attr)
343 {
344 return false;
345 }
346
347 static inline void sysfs_remove_files(struct kobject *kobj,
348 const struct attribute **attr)
349 {
350 }
351
352 static inline int sysfs_create_bin_file(struct kobject *kobj,
353 const struct bin_attribute *attr)
354 {
355 return 0;
356 }
357
358 static inline void sysfs_remove_bin_file(struct kobject *kobj,
359 const struct bin_attribute *attr)
360 {
361 }
362
363 static inline int sysfs_create_link(struct kobject *kobj,
364 struct kobject *target, const char *name)
365 {
366 return 0;
367 }
368
369 static inline int sysfs_create_link_nowarn(struct kobject *kobj,
370 struct kobject *target,
371 const char *name)
372 {
373 return 0;
374 }
375
376 static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
377 {
378 }
379
380 static inline int sysfs_rename_link_ns(struct kobject *k, struct kobject *t,
381 const char *old_name,
382 const char *new_name, const void *ns)
383 {
384 return 0;
385 }
386
387 static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
388 const char *name)
389 {
390 }
391
392 static inline int sysfs_create_group(struct kobject *kobj,
393 const struct attribute_group *grp)
394 {
395 return 0;
396 }
397
398 static inline int sysfs_create_groups(struct kobject *kobj,
399 const struct attribute_group **groups)
400 {
401 return 0;
402 }
403
404 static inline int sysfs_update_group(struct kobject *kobj,
405 const struct attribute_group *grp)
406 {
407 return 0;
408 }
409
410 static inline void sysfs_remove_group(struct kobject *kobj,
411 const struct attribute_group *grp)
412 {
413 }
414
415 static inline void sysfs_remove_groups(struct kobject *kobj,
416 const struct attribute_group **groups)
417 {
418 }
419
420 static inline int sysfs_add_file_to_group(struct kobject *kobj,
421 const struct attribute *attr, const char *group)
422 {
423 return 0;
424 }
425
426 static inline void sysfs_remove_file_from_group(struct kobject *kobj,
427 const struct attribute *attr, const char *group)
428 {
429 }
430
431 static inline int sysfs_merge_group(struct kobject *kobj,
432 const struct attribute_group *grp)
433 {
434 return 0;
435 }
436
437 static inline void sysfs_unmerge_group(struct kobject *kobj,
438 const struct attribute_group *grp)
439 {
440 }
441
442 static inline int sysfs_add_link_to_group(struct kobject *kobj,
443 const char *group_name, struct kobject *target,
444 const char *link_name)
445 {
446 return 0;
447 }
448
449 static inline void sysfs_remove_link_from_group(struct kobject *kobj,
450 const char *group_name, const char *link_name)
451 {
452 }
453
454 static inline void sysfs_notify(struct kobject *kobj, const char *dir,
455 const char *attr)
456 {
457 }
458
459 static inline int __must_check sysfs_init(void)
460 {
461 return 0;
462 }
463
464 static inline void sysfs_enable_ns(struct kernfs_node *kn)
465 {
466 }
467
468 #endif /* CONFIG_SYSFS */
469
470 static inline int __must_check sysfs_create_file(struct kobject *kobj,
471 const struct attribute *attr)
472 {
473 return sysfs_create_file_ns(kobj, attr, NULL);
474 }
475
476 static inline void sysfs_remove_file(struct kobject *kobj,
477 const struct attribute *attr)
478 {
479 sysfs_remove_file_ns(kobj, attr, NULL);
480 }
481
482 static inline int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
483 const char *old_name, const char *new_name)
484 {
485 return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL);
486 }
487
488 static inline void sysfs_notify_dirent(struct kernfs_node *kn)
489 {
490 kernfs_notify(kn);
491 }
492
493 static inline struct kernfs_node *sysfs_get_dirent(struct kernfs_node *parent,
494 const unsigned char *name)
495 {
496 return kernfs_find_and_get(parent, name);
497 }
498
499 static inline struct kernfs_node *sysfs_get(struct kernfs_node *kn)
500 {
501 kernfs_get(kn);
502 return kn;
503 }
504
505 static inline void sysfs_put(struct kernfs_node *kn)
506 {
507 kernfs_put(kn);
508 }
509
510 #endif /* _SYSFS_H_ */
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