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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/sysfs/file.c - sysfs regular (text) file implementation
4 *
5 * Copyright (c) 2001-3 Patrick Mochel
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#include <linux/module.h>
13#include <linux/kobject.h>
14#include <linux/slab.h>
15#include <linux/list.h>
16#include <linux/mutex.h>
17#include <linux/seq_file.h>
18
19#include "sysfs.h"
20
21/*
22 * Determine ktype->sysfs_ops for the given kernfs_node. This function
23 * must be called while holding an active reference.
24 */
25static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
26{
27 struct kobject *kobj = kn->parent->priv;
28
29 if (kn->flags & KERNFS_LOCKDEP)
30 lockdep_assert_held(kn);
31 return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
32}
33
34/*
35 * Reads on sysfs are handled through seq_file, which takes care of hairy
36 * details like buffering and seeking. The following function pipes
37 * sysfs_ops->show() result through seq_file.
38 */
39static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
40{
41 struct kernfs_open_file *of = sf->private;
42 struct kobject *kobj = of->kn->parent->priv;
43 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
44 ssize_t count;
45 char *buf;
46
47 /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
48 count = seq_get_buf(sf, &buf);
49 if (count < PAGE_SIZE) {
50 seq_commit(sf, -1);
51 return 0;
52 }
53 memset(buf, 0, PAGE_SIZE);
54
55 /*
56 * Invoke show(). Control may reach here via seq file lseek even
57 * if @ops->show() isn't implemented.
58 */
59 if (ops->show) {
60 count = ops->show(kobj, of->kn->priv, buf);
61 if (count < 0)
62 return count;
63 }
64
65 /*
66 * The code works fine with PAGE_SIZE return but it's likely to
67 * indicate truncated result or overflow in normal use cases.
68 */
69 if (count >= (ssize_t)PAGE_SIZE) {
70 printk("fill_read_buffer: %pS returned bad count\n",
71 ops->show);
72 /* Try to struggle along */
73 count = PAGE_SIZE - 1;
74 }
75 seq_commit(sf, count);
76 return 0;
77}
78
79static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
80 size_t count, loff_t pos)
81{
82 struct bin_attribute *battr = of->kn->priv;
83 struct kobject *kobj = of->kn->parent->priv;
84 loff_t size = file_inode(of->file)->i_size;
85
86 if (!count)
87 return 0;
88
89 if (size) {
90 if (pos >= size)
91 return 0;
92 if (pos + count > size)
93 count = size - pos;
94 }
95
96 if (!battr->read)
97 return -EIO;
98
99 return battr->read(of->file, kobj, battr, buf, pos, count);
100}
101
102/* kernfs read callback for regular sysfs files with pre-alloc */
103static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
104 size_t count, loff_t pos)
105{
106 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
107 struct kobject *kobj = of->kn->parent->priv;
108 ssize_t len;
109
110 /*
111 * If buf != of->prealloc_buf, we don't know how
112 * large it is, so cannot safely pass it to ->show
113 */
114 if (WARN_ON_ONCE(buf != of->prealloc_buf))
115 return 0;
116 len = ops->show(kobj, of->kn->priv, buf);
117 if (len < 0)
118 return len;
119 if (pos) {
120 if (len <= pos)
121 return 0;
122 len -= pos;
123 memmove(buf, buf + pos, len);
124 }
125 return min_t(ssize_t, count, len);
126}
127
128/* kernfs write callback for regular sysfs files */
129static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
130 size_t count, loff_t pos)
131{
132 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
133 struct kobject *kobj = of->kn->parent->priv;
134
135 if (!count)
136 return 0;
137
138 return ops->store(kobj, of->kn->priv, buf, count);
139}
140
141/* kernfs write callback for bin sysfs files */
142static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
143 size_t count, loff_t pos)
144{
145 struct bin_attribute *battr = of->kn->priv;
146 struct kobject *kobj = of->kn->parent->priv;
147 loff_t size = file_inode(of->file)->i_size;
148
149 if (size) {
150 if (size <= pos)
151 return -EFBIG;
152 count = min_t(ssize_t, count, size - pos);
153 }
154 if (!count)
155 return 0;
156
157 if (!battr->write)
158 return -EIO;
159
160 return battr->write(of->file, kobj, battr, buf, pos, count);
161}
162
163static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
164 struct vm_area_struct *vma)
165{
166 struct bin_attribute *battr = of->kn->priv;
167 struct kobject *kobj = of->kn->parent->priv;
168
169 return battr->mmap(of->file, kobj, battr, vma);
170}
171
172void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
173{
174 struct kernfs_node *kn = kobj->sd, *tmp;
175
176 if (kn && dir)
177 kn = kernfs_find_and_get(kn, dir);
178 else
179 kernfs_get(kn);
180
181 if (kn && attr) {
182 tmp = kernfs_find_and_get(kn, attr);
183 kernfs_put(kn);
184 kn = tmp;
185 }
186
187 if (kn) {
188 kernfs_notify(kn);
189 kernfs_put(kn);
190 }
191}
192EXPORT_SYMBOL_GPL(sysfs_notify);
193
194static const struct kernfs_ops sysfs_file_kfops_empty = {
195};
196
197static const struct kernfs_ops sysfs_file_kfops_ro = {
198 .seq_show = sysfs_kf_seq_show,
199};
200
201static const struct kernfs_ops sysfs_file_kfops_wo = {
202 .write = sysfs_kf_write,
203};
204
205static const struct kernfs_ops sysfs_file_kfops_rw = {
206 .seq_show = sysfs_kf_seq_show,
207 .write = sysfs_kf_write,
208};
209
210static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
211 .read = sysfs_kf_read,
212 .prealloc = true,
213};
214
215static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
216 .write = sysfs_kf_write,
217 .prealloc = true,
218};
219
220static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
221 .read = sysfs_kf_read,
222 .write = sysfs_kf_write,
223 .prealloc = true,
224};
225
226static const struct kernfs_ops sysfs_bin_kfops_ro = {
227 .read = sysfs_kf_bin_read,
228};
229
230static const struct kernfs_ops sysfs_bin_kfops_wo = {
231 .write = sysfs_kf_bin_write,
232};
233
234static const struct kernfs_ops sysfs_bin_kfops_rw = {
235 .read = sysfs_kf_bin_read,
236 .write = sysfs_kf_bin_write,
237};
238
239static const struct kernfs_ops sysfs_bin_kfops_mmap = {
240 .read = sysfs_kf_bin_read,
241 .write = sysfs_kf_bin_write,
242 .mmap = sysfs_kf_bin_mmap,
243};
244
245int sysfs_add_file_mode_ns(struct kernfs_node *parent,
246 const struct attribute *attr, bool is_bin,
247 umode_t mode, kuid_t uid, kgid_t gid, const void *ns)
248{
249 struct lock_class_key *key = NULL;
250 const struct kernfs_ops *ops;
251 struct kernfs_node *kn;
252 loff_t size;
253
254 if (!is_bin) {
255 struct kobject *kobj = parent->priv;
256 const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
257
258 /* every kobject with an attribute needs a ktype assigned */
259 if (WARN(!sysfs_ops, KERN_ERR
260 "missing sysfs attribute operations for kobject: %s\n",
261 kobject_name(kobj)))
262 return -EINVAL;
263
264 if (sysfs_ops->show && sysfs_ops->store) {
265 if (mode & SYSFS_PREALLOC)
266 ops = &sysfs_prealloc_kfops_rw;
267 else
268 ops = &sysfs_file_kfops_rw;
269 } else if (sysfs_ops->show) {
270 if (mode & SYSFS_PREALLOC)
271 ops = &sysfs_prealloc_kfops_ro;
272 else
273 ops = &sysfs_file_kfops_ro;
274 } else if (sysfs_ops->store) {
275 if (mode & SYSFS_PREALLOC)
276 ops = &sysfs_prealloc_kfops_wo;
277 else
278 ops = &sysfs_file_kfops_wo;
279 } else
280 ops = &sysfs_file_kfops_empty;
281
282 size = PAGE_SIZE;
283 } else {
284 struct bin_attribute *battr = (void *)attr;
285
286 if (battr->mmap)
287 ops = &sysfs_bin_kfops_mmap;
288 else if (battr->read && battr->write)
289 ops = &sysfs_bin_kfops_rw;
290 else if (battr->read)
291 ops = &sysfs_bin_kfops_ro;
292 else if (battr->write)
293 ops = &sysfs_bin_kfops_wo;
294 else
295 ops = &sysfs_file_kfops_empty;
296
297 size = battr->size;
298 }
299
300#ifdef CONFIG_DEBUG_LOCK_ALLOC
301 if (!attr->ignore_lockdep)
302 key = attr->key ?: (struct lock_class_key *)&attr->skey;
303#endif
304
305 kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
306 size, ops, (void *)attr, ns, key);
307 if (IS_ERR(kn)) {
308 if (PTR_ERR(kn) == -EEXIST)
309 sysfs_warn_dup(parent, attr->name);
310 return PTR_ERR(kn);
311 }
312 return 0;
313}
314
315/**
316 * sysfs_create_file_ns - create an attribute file for an object with custom ns
317 * @kobj: object we're creating for
318 * @attr: attribute descriptor
319 * @ns: namespace the new file should belong to
320 */
321int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
322 const void *ns)
323{
324 kuid_t uid;
325 kgid_t gid;
326
327 if (WARN_ON(!kobj || !kobj->sd || !attr))
328 return -EINVAL;
329
330 kobject_get_ownership(kobj, &uid, &gid);
331 return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode,
332 uid, gid, ns);
333
334}
335EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
336
337int sysfs_create_files(struct kobject *kobj, const struct attribute * const *ptr)
338{
339 int err = 0;
340 int i;
341
342 for (i = 0; ptr[i] && !err; i++)
343 err = sysfs_create_file(kobj, ptr[i]);
344 if (err)
345 while (--i >= 0)
346 sysfs_remove_file(kobj, ptr[i]);
347 return err;
348}
349EXPORT_SYMBOL_GPL(sysfs_create_files);
350
351/**
352 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
353 * @kobj: object we're acting for.
354 * @attr: attribute descriptor.
355 * @group: group name.
356 */
357int sysfs_add_file_to_group(struct kobject *kobj,
358 const struct attribute *attr, const char *group)
359{
360 struct kernfs_node *parent;
361 kuid_t uid;
362 kgid_t gid;
363 int error;
364
365 if (group) {
366 parent = kernfs_find_and_get(kobj->sd, group);
367 } else {
368 parent = kobj->sd;
369 kernfs_get(parent);
370 }
371
372 if (!parent)
373 return -ENOENT;
374
375 kobject_get_ownership(kobj, &uid, &gid);
376 error = sysfs_add_file_mode_ns(parent, attr, false,
377 attr->mode, uid, gid, NULL);
378 kernfs_put(parent);
379
380 return error;
381}
382EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
383
384/**
385 * sysfs_chmod_file - update the modified mode value on an object attribute.
386 * @kobj: object we're acting for.
387 * @attr: attribute descriptor.
388 * @mode: file permissions.
389 *
390 */
391int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
392 umode_t mode)
393{
394 struct kernfs_node *kn;
395 struct iattr newattrs;
396 int rc;
397
398 kn = kernfs_find_and_get(kobj->sd, attr->name);
399 if (!kn)
400 return -ENOENT;
401
402 newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
403 newattrs.ia_valid = ATTR_MODE;
404
405 rc = kernfs_setattr(kn, &newattrs);
406
407 kernfs_put(kn);
408 return rc;
409}
410EXPORT_SYMBOL_GPL(sysfs_chmod_file);
411
412/**
413 * sysfs_break_active_protection - break "active" protection
414 * @kobj: The kernel object @attr is associated with.
415 * @attr: The attribute to break the "active" protection for.
416 *
417 * With sysfs, just like kernfs, deletion of an attribute is postponed until
418 * all active .show() and .store() callbacks have finished unless this function
419 * is called. Hence this function is useful in methods that implement self
420 * deletion.
421 */
422struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj,
423 const struct attribute *attr)
424{
425 struct kernfs_node *kn;
426
427 kobject_get(kobj);
428 kn = kernfs_find_and_get(kobj->sd, attr->name);
429 if (kn)
430 kernfs_break_active_protection(kn);
431 return kn;
432}
433EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
434
435/**
436 * sysfs_unbreak_active_protection - restore "active" protection
437 * @kn: Pointer returned by sysfs_break_active_protection().
438 *
439 * Undo the effects of sysfs_break_active_protection(). Since this function
440 * calls kernfs_put() on the kernfs node that corresponds to the 'attr'
441 * argument passed to sysfs_break_active_protection() that attribute may have
442 * been removed between the sysfs_break_active_protection() and
443 * sysfs_unbreak_active_protection() calls, it is not safe to access @kn after
444 * this function has returned.
445 */
446void sysfs_unbreak_active_protection(struct kernfs_node *kn)
447{
448 struct kobject *kobj = kn->parent->priv;
449
450 kernfs_unbreak_active_protection(kn);
451 kernfs_put(kn);
452 kobject_put(kobj);
453}
454EXPORT_SYMBOL_GPL(sysfs_unbreak_active_protection);
455
456/**
457 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
458 * @kobj: object we're acting for
459 * @attr: attribute descriptor
460 * @ns: namespace tag of the file to remove
461 *
462 * Hash the attribute name and namespace tag and kill the victim.
463 */
464void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
465 const void *ns)
466{
467 struct kernfs_node *parent = kobj->sd;
468
469 kernfs_remove_by_name_ns(parent, attr->name, ns);
470}
471EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
472
473/**
474 * sysfs_remove_file_self - remove an object attribute from its own method
475 * @kobj: object we're acting for
476 * @attr: attribute descriptor
477 *
478 * See kernfs_remove_self() for details.
479 */
480bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
481{
482 struct kernfs_node *parent = kobj->sd;
483 struct kernfs_node *kn;
484 bool ret;
485
486 kn = kernfs_find_and_get(parent, attr->name);
487 if (WARN_ON_ONCE(!kn))
488 return false;
489
490 ret = kernfs_remove_self(kn);
491
492 kernfs_put(kn);
493 return ret;
494}
495
496void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr)
497{
498 int i;
499
500 for (i = 0; ptr[i]; i++)
501 sysfs_remove_file(kobj, ptr[i]);
502}
503EXPORT_SYMBOL_GPL(sysfs_remove_files);
504
505/**
506 * sysfs_remove_file_from_group - remove an attribute file from a group.
507 * @kobj: object we're acting for.
508 * @attr: attribute descriptor.
509 * @group: group name.
510 */
511void sysfs_remove_file_from_group(struct kobject *kobj,
512 const struct attribute *attr, const char *group)
513{
514 struct kernfs_node *parent;
515
516 if (group) {
517 parent = kernfs_find_and_get(kobj->sd, group);
518 } else {
519 parent = kobj->sd;
520 kernfs_get(parent);
521 }
522
523 if (parent) {
524 kernfs_remove_by_name(parent, attr->name);
525 kernfs_put(parent);
526 }
527}
528EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
529
530/**
531 * sysfs_create_bin_file - create binary file for object.
532 * @kobj: object.
533 * @attr: attribute descriptor.
534 */
535int sysfs_create_bin_file(struct kobject *kobj,
536 const struct bin_attribute *attr)
537{
538 kuid_t uid;
539 kgid_t gid;
540
541 if (WARN_ON(!kobj || !kobj->sd || !attr))
542 return -EINVAL;
543
544 kobject_get_ownership(kobj, &uid, &gid);
545 return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true,
546 attr->attr.mode, uid, gid, NULL);
547}
548EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
549
550/**
551 * sysfs_remove_bin_file - remove binary file for object.
552 * @kobj: object.
553 * @attr: attribute descriptor.
554 */
555void sysfs_remove_bin_file(struct kobject *kobj,
556 const struct bin_attribute *attr)
557{
558 kernfs_remove_by_name(kobj->sd, attr->attr.name);
559}
560EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
1/*
2 * fs/sysfs/file.c - sysfs regular (text) file implementation
3 *
4 * Copyright (c) 2001-3 Patrick Mochel
5 * Copyright (c) 2007 SUSE Linux Products GmbH
6 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
7 *
8 * This file is released under the GPLv2.
9 *
10 * Please see Documentation/filesystems/sysfs.txt for more information.
11 */
12
13#include <linux/module.h>
14#include <linux/kobject.h>
15#include <linux/kallsyms.h>
16#include <linux/slab.h>
17#include <linux/list.h>
18#include <linux/mutex.h>
19#include <linux/seq_file.h>
20
21#include "sysfs.h"
22#include "../kernfs/kernfs-internal.h"
23
24/*
25 * Determine ktype->sysfs_ops for the given kernfs_node. This function
26 * must be called while holding an active reference.
27 */
28static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
29{
30 struct kobject *kobj = kn->parent->priv;
31
32 if (kn->flags & KERNFS_LOCKDEP)
33 lockdep_assert_held(kn);
34 return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
35}
36
37/*
38 * Reads on sysfs are handled through seq_file, which takes care of hairy
39 * details like buffering and seeking. The following function pipes
40 * sysfs_ops->show() result through seq_file.
41 */
42static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
43{
44 struct kernfs_open_file *of = sf->private;
45 struct kobject *kobj = of->kn->parent->priv;
46 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
47 ssize_t count;
48 char *buf;
49
50 /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
51 count = seq_get_buf(sf, &buf);
52 if (count < PAGE_SIZE) {
53 seq_commit(sf, -1);
54 return 0;
55 }
56 memset(buf, 0, PAGE_SIZE);
57
58 /*
59 * Invoke show(). Control may reach here via seq file lseek even
60 * if @ops->show() isn't implemented.
61 */
62 if (ops->show) {
63 count = ops->show(kobj, of->kn->priv, buf);
64 if (count < 0)
65 return count;
66 }
67
68 /*
69 * The code works fine with PAGE_SIZE return but it's likely to
70 * indicate truncated result or overflow in normal use cases.
71 */
72 if (count >= (ssize_t)PAGE_SIZE) {
73 print_symbol("fill_read_buffer: %s returned bad count\n",
74 (unsigned long)ops->show);
75 /* Try to struggle along */
76 count = PAGE_SIZE - 1;
77 }
78 seq_commit(sf, count);
79 return 0;
80}
81
82static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
83 size_t count, loff_t pos)
84{
85 struct bin_attribute *battr = of->kn->priv;
86 struct kobject *kobj = of->kn->parent->priv;
87 loff_t size = file_inode(of->file)->i_size;
88
89 if (!count)
90 return 0;
91
92 if (size) {
93 if (pos >= size)
94 return 0;
95 if (pos + count > size)
96 count = size - pos;
97 }
98
99 if (!battr->read)
100 return -EIO;
101
102 return battr->read(of->file, kobj, battr, buf, pos, count);
103}
104
105/* kernfs read callback for regular sysfs files with pre-alloc */
106static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
107 size_t count, loff_t pos)
108{
109 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
110 struct kobject *kobj = of->kn->parent->priv;
111 size_t len;
112
113 /*
114 * If buf != of->prealloc_buf, we don't know how
115 * large it is, so cannot safely pass it to ->show
116 */
117 if (pos || WARN_ON_ONCE(buf != of->prealloc_buf))
118 return 0;
119 len = ops->show(kobj, of->kn->priv, buf);
120 return min(count, len);
121}
122
123/* kernfs write callback for regular sysfs files */
124static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
125 size_t count, loff_t pos)
126{
127 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
128 struct kobject *kobj = of->kn->parent->priv;
129
130 if (!count)
131 return 0;
132
133 return ops->store(kobj, of->kn->priv, buf, count);
134}
135
136/* kernfs write callback for bin sysfs files */
137static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
138 size_t count, loff_t pos)
139{
140 struct bin_attribute *battr = of->kn->priv;
141 struct kobject *kobj = of->kn->parent->priv;
142 loff_t size = file_inode(of->file)->i_size;
143
144 if (size) {
145 if (size <= pos)
146 return -EFBIG;
147 count = min_t(ssize_t, count, size - pos);
148 }
149 if (!count)
150 return 0;
151
152 if (!battr->write)
153 return -EIO;
154
155 return battr->write(of->file, kobj, battr, buf, pos, count);
156}
157
158static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
159 struct vm_area_struct *vma)
160{
161 struct bin_attribute *battr = of->kn->priv;
162 struct kobject *kobj = of->kn->parent->priv;
163
164 return battr->mmap(of->file, kobj, battr, vma);
165}
166
167void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
168{
169 struct kernfs_node *kn = kobj->sd, *tmp;
170
171 if (kn && dir)
172 kn = kernfs_find_and_get(kn, dir);
173 else
174 kernfs_get(kn);
175
176 if (kn && attr) {
177 tmp = kernfs_find_and_get(kn, attr);
178 kernfs_put(kn);
179 kn = tmp;
180 }
181
182 if (kn) {
183 kernfs_notify(kn);
184 kernfs_put(kn);
185 }
186}
187EXPORT_SYMBOL_GPL(sysfs_notify);
188
189static const struct kernfs_ops sysfs_file_kfops_empty = {
190};
191
192static const struct kernfs_ops sysfs_file_kfops_ro = {
193 .seq_show = sysfs_kf_seq_show,
194};
195
196static const struct kernfs_ops sysfs_file_kfops_wo = {
197 .write = sysfs_kf_write,
198};
199
200static const struct kernfs_ops sysfs_file_kfops_rw = {
201 .seq_show = sysfs_kf_seq_show,
202 .write = sysfs_kf_write,
203};
204
205static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
206 .read = sysfs_kf_read,
207 .prealloc = true,
208};
209
210static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
211 .write = sysfs_kf_write,
212 .prealloc = true,
213};
214
215static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
216 .read = sysfs_kf_read,
217 .write = sysfs_kf_write,
218 .prealloc = true,
219};
220
221static const struct kernfs_ops sysfs_bin_kfops_ro = {
222 .read = sysfs_kf_bin_read,
223};
224
225static const struct kernfs_ops sysfs_bin_kfops_wo = {
226 .write = sysfs_kf_bin_write,
227};
228
229static const struct kernfs_ops sysfs_bin_kfops_rw = {
230 .read = sysfs_kf_bin_read,
231 .write = sysfs_kf_bin_write,
232};
233
234static const struct kernfs_ops sysfs_bin_kfops_mmap = {
235 .read = sysfs_kf_bin_read,
236 .write = sysfs_kf_bin_write,
237 .mmap = sysfs_kf_bin_mmap,
238};
239
240int sysfs_add_file_mode_ns(struct kernfs_node *parent,
241 const struct attribute *attr, bool is_bin,
242 umode_t mode, const void *ns)
243{
244 struct lock_class_key *key = NULL;
245 const struct kernfs_ops *ops;
246 struct kernfs_node *kn;
247 loff_t size;
248
249 if (!is_bin) {
250 struct kobject *kobj = parent->priv;
251 const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
252
253 /* every kobject with an attribute needs a ktype assigned */
254 if (WARN(!sysfs_ops, KERN_ERR
255 "missing sysfs attribute operations for kobject: %s\n",
256 kobject_name(kobj)))
257 return -EINVAL;
258
259 if (sysfs_ops->show && sysfs_ops->store) {
260 if (mode & SYSFS_PREALLOC)
261 ops = &sysfs_prealloc_kfops_rw;
262 else
263 ops = &sysfs_file_kfops_rw;
264 } else if (sysfs_ops->show) {
265 if (mode & SYSFS_PREALLOC)
266 ops = &sysfs_prealloc_kfops_ro;
267 else
268 ops = &sysfs_file_kfops_ro;
269 } else if (sysfs_ops->store) {
270 if (mode & SYSFS_PREALLOC)
271 ops = &sysfs_prealloc_kfops_wo;
272 else
273 ops = &sysfs_file_kfops_wo;
274 } else
275 ops = &sysfs_file_kfops_empty;
276
277 size = PAGE_SIZE;
278 } else {
279 struct bin_attribute *battr = (void *)attr;
280
281 if (battr->mmap)
282 ops = &sysfs_bin_kfops_mmap;
283 else if (battr->read && battr->write)
284 ops = &sysfs_bin_kfops_rw;
285 else if (battr->read)
286 ops = &sysfs_bin_kfops_ro;
287 else if (battr->write)
288 ops = &sysfs_bin_kfops_wo;
289 else
290 ops = &sysfs_file_kfops_empty;
291
292 size = battr->size;
293 }
294
295#ifdef CONFIG_DEBUG_LOCK_ALLOC
296 if (!attr->ignore_lockdep)
297 key = attr->key ?: (struct lock_class_key *)&attr->skey;
298#endif
299 kn = __kernfs_create_file(parent, attr->name, mode & 0777, size, ops,
300 (void *)attr, ns, key);
301 if (IS_ERR(kn)) {
302 if (PTR_ERR(kn) == -EEXIST)
303 sysfs_warn_dup(parent, attr->name);
304 return PTR_ERR(kn);
305 }
306 return 0;
307}
308
309int sysfs_add_file(struct kernfs_node *parent, const struct attribute *attr,
310 bool is_bin)
311{
312 return sysfs_add_file_mode_ns(parent, attr, is_bin, attr->mode, NULL);
313}
314
315/**
316 * sysfs_create_file_ns - create an attribute file for an object with custom ns
317 * @kobj: object we're creating for
318 * @attr: attribute descriptor
319 * @ns: namespace the new file should belong to
320 */
321int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
322 const void *ns)
323{
324 BUG_ON(!kobj || !kobj->sd || !attr);
325
326 return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode, ns);
327
328}
329EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
330
331int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
332{
333 int err = 0;
334 int i;
335
336 for (i = 0; ptr[i] && !err; i++)
337 err = sysfs_create_file(kobj, ptr[i]);
338 if (err)
339 while (--i >= 0)
340 sysfs_remove_file(kobj, ptr[i]);
341 return err;
342}
343EXPORT_SYMBOL_GPL(sysfs_create_files);
344
345/**
346 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
347 * @kobj: object we're acting for.
348 * @attr: attribute descriptor.
349 * @group: group name.
350 */
351int sysfs_add_file_to_group(struct kobject *kobj,
352 const struct attribute *attr, const char *group)
353{
354 struct kernfs_node *parent;
355 int error;
356
357 if (group) {
358 parent = kernfs_find_and_get(kobj->sd, group);
359 } else {
360 parent = kobj->sd;
361 kernfs_get(parent);
362 }
363
364 if (!parent)
365 return -ENOENT;
366
367 error = sysfs_add_file(parent, attr, false);
368 kernfs_put(parent);
369
370 return error;
371}
372EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
373
374/**
375 * sysfs_chmod_file - update the modified mode value on an object attribute.
376 * @kobj: object we're acting for.
377 * @attr: attribute descriptor.
378 * @mode: file permissions.
379 *
380 */
381int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
382 umode_t mode)
383{
384 struct kernfs_node *kn;
385 struct iattr newattrs;
386 int rc;
387
388 kn = kernfs_find_and_get(kobj->sd, attr->name);
389 if (!kn)
390 return -ENOENT;
391
392 newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
393 newattrs.ia_valid = ATTR_MODE;
394
395 rc = kernfs_setattr(kn, &newattrs);
396
397 kernfs_put(kn);
398 return rc;
399}
400EXPORT_SYMBOL_GPL(sysfs_chmod_file);
401
402/**
403 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
404 * @kobj: object we're acting for
405 * @attr: attribute descriptor
406 * @ns: namespace tag of the file to remove
407 *
408 * Hash the attribute name and namespace tag and kill the victim.
409 */
410void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
411 const void *ns)
412{
413 struct kernfs_node *parent = kobj->sd;
414
415 kernfs_remove_by_name_ns(parent, attr->name, ns);
416}
417EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
418
419/**
420 * sysfs_remove_file_self - remove an object attribute from its own method
421 * @kobj: object we're acting for
422 * @attr: attribute descriptor
423 *
424 * See kernfs_remove_self() for details.
425 */
426bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
427{
428 struct kernfs_node *parent = kobj->sd;
429 struct kernfs_node *kn;
430 bool ret;
431
432 kn = kernfs_find_and_get(parent, attr->name);
433 if (WARN_ON_ONCE(!kn))
434 return false;
435
436 ret = kernfs_remove_self(kn);
437
438 kernfs_put(kn);
439 return ret;
440}
441
442void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
443{
444 int i;
445 for (i = 0; ptr[i]; i++)
446 sysfs_remove_file(kobj, ptr[i]);
447}
448EXPORT_SYMBOL_GPL(sysfs_remove_files);
449
450/**
451 * sysfs_remove_file_from_group - remove an attribute file from a group.
452 * @kobj: object we're acting for.
453 * @attr: attribute descriptor.
454 * @group: group name.
455 */
456void sysfs_remove_file_from_group(struct kobject *kobj,
457 const struct attribute *attr, const char *group)
458{
459 struct kernfs_node *parent;
460
461 if (group) {
462 parent = kernfs_find_and_get(kobj->sd, group);
463 } else {
464 parent = kobj->sd;
465 kernfs_get(parent);
466 }
467
468 if (parent) {
469 kernfs_remove_by_name(parent, attr->name);
470 kernfs_put(parent);
471 }
472}
473EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
474
475/**
476 * sysfs_create_bin_file - create binary file for object.
477 * @kobj: object.
478 * @attr: attribute descriptor.
479 */
480int sysfs_create_bin_file(struct kobject *kobj,
481 const struct bin_attribute *attr)
482{
483 BUG_ON(!kobj || !kobj->sd || !attr);
484
485 return sysfs_add_file(kobj->sd, &attr->attr, true);
486}
487EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
488
489/**
490 * sysfs_remove_bin_file - remove binary file for object.
491 * @kobj: object.
492 * @attr: attribute descriptor.
493 */
494void sysfs_remove_bin_file(struct kobject *kobj,
495 const struct bin_attribute *attr)
496{
497 kernfs_remove_by_name(kobj->sd, attr->attr.name);
498}
499EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);