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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 ssize_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 (WARN_ON_ONCE(buf != of->prealloc_buf))
118 return 0;
119 len = ops->show(kobj, of->kn->priv, buf);
120 if (len < 0)
121 return len;
122 if (pos) {
123 if (len <= pos)
124 return 0;
125 len -= pos;
126 memmove(buf, buf + pos, len);
127 }
128 return min_t(ssize_t, count, len);
129}
130
131/* kernfs write callback for regular sysfs files */
132static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
133 size_t count, loff_t pos)
134{
135 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
136 struct kobject *kobj = of->kn->parent->priv;
137
138 if (!count)
139 return 0;
140
141 return ops->store(kobj, of->kn->priv, buf, count);
142}
143
144/* kernfs write callback for bin sysfs files */
145static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
146 size_t count, loff_t pos)
147{
148 struct bin_attribute *battr = of->kn->priv;
149 struct kobject *kobj = of->kn->parent->priv;
150 loff_t size = file_inode(of->file)->i_size;
151
152 if (size) {
153 if (size <= pos)
154 return -EFBIG;
155 count = min_t(ssize_t, count, size - pos);
156 }
157 if (!count)
158 return 0;
159
160 if (!battr->write)
161 return -EIO;
162
163 return battr->write(of->file, kobj, battr, buf, pos, count);
164}
165
166static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
167 struct vm_area_struct *vma)
168{
169 struct bin_attribute *battr = of->kn->priv;
170 struct kobject *kobj = of->kn->parent->priv;
171
172 return battr->mmap(of->file, kobj, battr, vma);
173}
174
175void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
176{
177 struct kernfs_node *kn = kobj->sd, *tmp;
178
179 if (kn && dir)
180 kn = kernfs_find_and_get(kn, dir);
181 else
182 kernfs_get(kn);
183
184 if (kn && attr) {
185 tmp = kernfs_find_and_get(kn, attr);
186 kernfs_put(kn);
187 kn = tmp;
188 }
189
190 if (kn) {
191 kernfs_notify(kn);
192 kernfs_put(kn);
193 }
194}
195EXPORT_SYMBOL_GPL(sysfs_notify);
196
197static const struct kernfs_ops sysfs_file_kfops_empty = {
198};
199
200static const struct kernfs_ops sysfs_file_kfops_ro = {
201 .seq_show = sysfs_kf_seq_show,
202};
203
204static const struct kernfs_ops sysfs_file_kfops_wo = {
205 .write = sysfs_kf_write,
206};
207
208static const struct kernfs_ops sysfs_file_kfops_rw = {
209 .seq_show = sysfs_kf_seq_show,
210 .write = sysfs_kf_write,
211};
212
213static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
214 .read = sysfs_kf_read,
215 .prealloc = true,
216};
217
218static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
219 .write = sysfs_kf_write,
220 .prealloc = true,
221};
222
223static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
224 .read = sysfs_kf_read,
225 .write = sysfs_kf_write,
226 .prealloc = true,
227};
228
229static const struct kernfs_ops sysfs_bin_kfops_ro = {
230 .read = sysfs_kf_bin_read,
231};
232
233static const struct kernfs_ops sysfs_bin_kfops_wo = {
234 .write = sysfs_kf_bin_write,
235};
236
237static const struct kernfs_ops sysfs_bin_kfops_rw = {
238 .read = sysfs_kf_bin_read,
239 .write = sysfs_kf_bin_write,
240};
241
242static const struct kernfs_ops sysfs_bin_kfops_mmap = {
243 .read = sysfs_kf_bin_read,
244 .write = sysfs_kf_bin_write,
245 .mmap = sysfs_kf_bin_mmap,
246};
247
248int sysfs_add_file_mode_ns(struct kernfs_node *parent,
249 const struct attribute *attr, bool is_bin,
250 umode_t mode, const void *ns)
251{
252 struct lock_class_key *key = NULL;
253 const struct kernfs_ops *ops;
254 struct kernfs_node *kn;
255 loff_t size;
256
257 if (!is_bin) {
258 struct kobject *kobj = parent->priv;
259 const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
260
261 /* every kobject with an attribute needs a ktype assigned */
262 if (WARN(!sysfs_ops, KERN_ERR
263 "missing sysfs attribute operations for kobject: %s\n",
264 kobject_name(kobj)))
265 return -EINVAL;
266
267 if (sysfs_ops->show && sysfs_ops->store) {
268 if (mode & SYSFS_PREALLOC)
269 ops = &sysfs_prealloc_kfops_rw;
270 else
271 ops = &sysfs_file_kfops_rw;
272 } else if (sysfs_ops->show) {
273 if (mode & SYSFS_PREALLOC)
274 ops = &sysfs_prealloc_kfops_ro;
275 else
276 ops = &sysfs_file_kfops_ro;
277 } else if (sysfs_ops->store) {
278 if (mode & SYSFS_PREALLOC)
279 ops = &sysfs_prealloc_kfops_wo;
280 else
281 ops = &sysfs_file_kfops_wo;
282 } else
283 ops = &sysfs_file_kfops_empty;
284
285 size = PAGE_SIZE;
286 } else {
287 struct bin_attribute *battr = (void *)attr;
288
289 if (battr->mmap)
290 ops = &sysfs_bin_kfops_mmap;
291 else if (battr->read && battr->write)
292 ops = &sysfs_bin_kfops_rw;
293 else if (battr->read)
294 ops = &sysfs_bin_kfops_ro;
295 else if (battr->write)
296 ops = &sysfs_bin_kfops_wo;
297 else
298 ops = &sysfs_file_kfops_empty;
299
300 size = battr->size;
301 }
302
303#ifdef CONFIG_DEBUG_LOCK_ALLOC
304 if (!attr->ignore_lockdep)
305 key = attr->key ?: (struct lock_class_key *)&attr->skey;
306#endif
307 kn = __kernfs_create_file(parent, attr->name, mode & 0777, size, ops,
308 (void *)attr, ns, key);
309 if (IS_ERR(kn)) {
310 if (PTR_ERR(kn) == -EEXIST)
311 sysfs_warn_dup(parent, attr->name);
312 return PTR_ERR(kn);
313 }
314 return 0;
315}
316
317int sysfs_add_file(struct kernfs_node *parent, const struct attribute *attr,
318 bool is_bin)
319{
320 return sysfs_add_file_mode_ns(parent, attr, is_bin, attr->mode, NULL);
321}
322
323/**
324 * sysfs_create_file_ns - create an attribute file for an object with custom ns
325 * @kobj: object we're creating for
326 * @attr: attribute descriptor
327 * @ns: namespace the new file should belong to
328 */
329int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
330 const void *ns)
331{
332 BUG_ON(!kobj || !kobj->sd || !attr);
333
334 return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode, ns);
335
336}
337EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
338
339int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
340{
341 int err = 0;
342 int i;
343
344 for (i = 0; ptr[i] && !err; i++)
345 err = sysfs_create_file(kobj, ptr[i]);
346 if (err)
347 while (--i >= 0)
348 sysfs_remove_file(kobj, ptr[i]);
349 return err;
350}
351EXPORT_SYMBOL_GPL(sysfs_create_files);
352
353/**
354 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
355 * @kobj: object we're acting for.
356 * @attr: attribute descriptor.
357 * @group: group name.
358 */
359int sysfs_add_file_to_group(struct kobject *kobj,
360 const struct attribute *attr, const char *group)
361{
362 struct kernfs_node *parent;
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 error = sysfs_add_file(parent, attr, false);
376 kernfs_put(parent);
377
378 return error;
379}
380EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
381
382/**
383 * sysfs_chmod_file - update the modified mode value on an object attribute.
384 * @kobj: object we're acting for.
385 * @attr: attribute descriptor.
386 * @mode: file permissions.
387 *
388 */
389int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
390 umode_t mode)
391{
392 struct kernfs_node *kn;
393 struct iattr newattrs;
394 int rc;
395
396 kn = kernfs_find_and_get(kobj->sd, attr->name);
397 if (!kn)
398 return -ENOENT;
399
400 newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
401 newattrs.ia_valid = ATTR_MODE;
402
403 rc = kernfs_setattr(kn, &newattrs);
404
405 kernfs_put(kn);
406 return rc;
407}
408EXPORT_SYMBOL_GPL(sysfs_chmod_file);
409
410/**
411 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
412 * @kobj: object we're acting for
413 * @attr: attribute descriptor
414 * @ns: namespace tag of the file to remove
415 *
416 * Hash the attribute name and namespace tag and kill the victim.
417 */
418void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
419 const void *ns)
420{
421 struct kernfs_node *parent = kobj->sd;
422
423 kernfs_remove_by_name_ns(parent, attr->name, ns);
424}
425EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
426
427/**
428 * sysfs_remove_file_self - remove an object attribute from its own method
429 * @kobj: object we're acting for
430 * @attr: attribute descriptor
431 *
432 * See kernfs_remove_self() for details.
433 */
434bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
435{
436 struct kernfs_node *parent = kobj->sd;
437 struct kernfs_node *kn;
438 bool ret;
439
440 kn = kernfs_find_and_get(parent, attr->name);
441 if (WARN_ON_ONCE(!kn))
442 return false;
443
444 ret = kernfs_remove_self(kn);
445
446 kernfs_put(kn);
447 return ret;
448}
449
450void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
451{
452 int i;
453 for (i = 0; ptr[i]; i++)
454 sysfs_remove_file(kobj, ptr[i]);
455}
456EXPORT_SYMBOL_GPL(sysfs_remove_files);
457
458/**
459 * sysfs_remove_file_from_group - remove an attribute file from a group.
460 * @kobj: object we're acting for.
461 * @attr: attribute descriptor.
462 * @group: group name.
463 */
464void sysfs_remove_file_from_group(struct kobject *kobj,
465 const struct attribute *attr, const char *group)
466{
467 struct kernfs_node *parent;
468
469 if (group) {
470 parent = kernfs_find_and_get(kobj->sd, group);
471 } else {
472 parent = kobj->sd;
473 kernfs_get(parent);
474 }
475
476 if (parent) {
477 kernfs_remove_by_name(parent, attr->name);
478 kernfs_put(parent);
479 }
480}
481EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
482
483/**
484 * sysfs_create_bin_file - create binary file for object.
485 * @kobj: object.
486 * @attr: attribute descriptor.
487 */
488int sysfs_create_bin_file(struct kobject *kobj,
489 const struct bin_attribute *attr)
490{
491 BUG_ON(!kobj || !kobj->sd || !attr);
492
493 return sysfs_add_file(kobj->sd, &attr->attr, true);
494}
495EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
496
497/**
498 * sysfs_remove_bin_file - remove binary file for object.
499 * @kobj: object.
500 * @attr: attribute descriptor.
501 */
502void sysfs_remove_bin_file(struct kobject *kobj,
503 const struct bin_attribute *attr)
504{
505 kernfs_remove_by_name(kobj->sd, attr->attr.name);
506}
507EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
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);