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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#include "../kernfs/kernfs-internal.h"
21
22/*
23 * Determine ktype->sysfs_ops for the given kernfs_node. This function
24 * must be called while holding an active reference.
25 */
26static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
27{
28 struct kobject *kobj = kn->parent->priv;
29
30 if (kn->flags & KERNFS_LOCKDEP)
31 lockdep_assert_held(kn);
32 return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
33}
34
35/*
36 * Reads on sysfs are handled through seq_file, which takes care of hairy
37 * details like buffering and seeking. The following function pipes
38 * sysfs_ops->show() result through seq_file.
39 */
40static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
41{
42 struct kernfs_open_file *of = sf->private;
43 struct kobject *kobj = of->kn->parent->priv;
44 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
45 ssize_t count;
46 char *buf;
47
48 /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
49 count = seq_get_buf(sf, &buf);
50 if (count < PAGE_SIZE) {
51 seq_commit(sf, -1);
52 return 0;
53 }
54 memset(buf, 0, PAGE_SIZE);
55
56 /*
57 * Invoke show(). Control may reach here via seq file lseek even
58 * if @ops->show() isn't implemented.
59 */
60 if (ops->show) {
61 count = ops->show(kobj, of->kn->priv, buf);
62 if (count < 0)
63 return count;
64 }
65
66 /*
67 * The code works fine with PAGE_SIZE return but it's likely to
68 * indicate truncated result or overflow in normal use cases.
69 */
70 if (count >= (ssize_t)PAGE_SIZE) {
71 printk("fill_read_buffer: %pS returned bad count\n",
72 ops->show);
73 /* Try to struggle along */
74 count = PAGE_SIZE - 1;
75 }
76 seq_commit(sf, count);
77 return 0;
78}
79
80static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
81 size_t count, loff_t pos)
82{
83 struct bin_attribute *battr = of->kn->priv;
84 struct kobject *kobj = of->kn->parent->priv;
85 loff_t size = file_inode(of->file)->i_size;
86
87 if (!count)
88 return 0;
89
90 if (size) {
91 if (pos >= size)
92 return 0;
93 if (pos + count > size)
94 count = size - pos;
95 }
96
97 if (!battr->read)
98 return -EIO;
99
100 return battr->read(of->file, kobj, battr, buf, pos, count);
101}
102
103/* kernfs read callback for regular sysfs files with pre-alloc */
104static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
105 size_t count, loff_t pos)
106{
107 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
108 struct kobject *kobj = of->kn->parent->priv;
109 ssize_t len;
110
111 /*
112 * If buf != of->prealloc_buf, we don't know how
113 * large it is, so cannot safely pass it to ->show
114 */
115 if (WARN_ON_ONCE(buf != of->prealloc_buf))
116 return 0;
117 len = ops->show(kobj, of->kn->priv, buf);
118 if (len < 0)
119 return len;
120 if (pos) {
121 if (len <= pos)
122 return 0;
123 len -= pos;
124 memmove(buf, buf + pos, len);
125 }
126 return min_t(ssize_t, count, len);
127}
128
129/* kernfs write callback for regular sysfs files */
130static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
131 size_t count, loff_t pos)
132{
133 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
134 struct kobject *kobj = of->kn->parent->priv;
135
136 if (!count)
137 return 0;
138
139 return ops->store(kobj, of->kn->priv, buf, count);
140}
141
142/* kernfs write callback for bin sysfs files */
143static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
144 size_t count, loff_t pos)
145{
146 struct bin_attribute *battr = of->kn->priv;
147 struct kobject *kobj = of->kn->parent->priv;
148 loff_t size = file_inode(of->file)->i_size;
149
150 if (size) {
151 if (size <= pos)
152 return -EFBIG;
153 count = min_t(ssize_t, count, size - pos);
154 }
155 if (!count)
156 return 0;
157
158 if (!battr->write)
159 return -EIO;
160
161 return battr->write(of->file, kobj, battr, buf, pos, count);
162}
163
164static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
165 struct vm_area_struct *vma)
166{
167 struct bin_attribute *battr = of->kn->priv;
168 struct kobject *kobj = of->kn->parent->priv;
169
170 return battr->mmap(of->file, kobj, battr, vma);
171}
172
173void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
174{
175 struct kernfs_node *kn = kobj->sd, *tmp;
176
177 if (kn && dir)
178 kn = kernfs_find_and_get(kn, dir);
179 else
180 kernfs_get(kn);
181
182 if (kn && attr) {
183 tmp = kernfs_find_and_get(kn, attr);
184 kernfs_put(kn);
185 kn = tmp;
186 }
187
188 if (kn) {
189 kernfs_notify(kn);
190 kernfs_put(kn);
191 }
192}
193EXPORT_SYMBOL_GPL(sysfs_notify);
194
195static const struct kernfs_ops sysfs_file_kfops_empty = {
196};
197
198static const struct kernfs_ops sysfs_file_kfops_ro = {
199 .seq_show = sysfs_kf_seq_show,
200};
201
202static const struct kernfs_ops sysfs_file_kfops_wo = {
203 .write = sysfs_kf_write,
204};
205
206static const struct kernfs_ops sysfs_file_kfops_rw = {
207 .seq_show = sysfs_kf_seq_show,
208 .write = sysfs_kf_write,
209};
210
211static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
212 .read = sysfs_kf_read,
213 .prealloc = true,
214};
215
216static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
217 .write = sysfs_kf_write,
218 .prealloc = true,
219};
220
221static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
222 .read = sysfs_kf_read,
223 .write = sysfs_kf_write,
224 .prealloc = true,
225};
226
227static const struct kernfs_ops sysfs_bin_kfops_ro = {
228 .read = sysfs_kf_bin_read,
229};
230
231static const struct kernfs_ops sysfs_bin_kfops_wo = {
232 .write = sysfs_kf_bin_write,
233};
234
235static const struct kernfs_ops sysfs_bin_kfops_rw = {
236 .read = sysfs_kf_bin_read,
237 .write = sysfs_kf_bin_write,
238};
239
240static const struct kernfs_ops sysfs_bin_kfops_mmap = {
241 .read = sysfs_kf_bin_read,
242 .write = sysfs_kf_bin_write,
243 .mmap = sysfs_kf_bin_mmap,
244};
245
246int sysfs_add_file_mode_ns(struct kernfs_node *parent,
247 const struct attribute *attr, bool is_bin,
248 umode_t mode, const void *ns)
249{
250 struct lock_class_key *key = NULL;
251 const struct kernfs_ops *ops;
252 struct kernfs_node *kn;
253 loff_t size;
254
255 if (!is_bin) {
256 struct kobject *kobj = parent->priv;
257 const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
258
259 /* every kobject with an attribute needs a ktype assigned */
260 if (WARN(!sysfs_ops, KERN_ERR
261 "missing sysfs attribute operations for kobject: %s\n",
262 kobject_name(kobj)))
263 return -EINVAL;
264
265 if (sysfs_ops->show && sysfs_ops->store) {
266 if (mode & SYSFS_PREALLOC)
267 ops = &sysfs_prealloc_kfops_rw;
268 else
269 ops = &sysfs_file_kfops_rw;
270 } else if (sysfs_ops->show) {
271 if (mode & SYSFS_PREALLOC)
272 ops = &sysfs_prealloc_kfops_ro;
273 else
274 ops = &sysfs_file_kfops_ro;
275 } else if (sysfs_ops->store) {
276 if (mode & SYSFS_PREALLOC)
277 ops = &sysfs_prealloc_kfops_wo;
278 else
279 ops = &sysfs_file_kfops_wo;
280 } else
281 ops = &sysfs_file_kfops_empty;
282
283 size = PAGE_SIZE;
284 } else {
285 struct bin_attribute *battr = (void *)attr;
286
287 if (battr->mmap)
288 ops = &sysfs_bin_kfops_mmap;
289 else if (battr->read && battr->write)
290 ops = &sysfs_bin_kfops_rw;
291 else if (battr->read)
292 ops = &sysfs_bin_kfops_ro;
293 else if (battr->write)
294 ops = &sysfs_bin_kfops_wo;
295 else
296 ops = &sysfs_file_kfops_empty;
297
298 size = battr->size;
299 }
300
301#ifdef CONFIG_DEBUG_LOCK_ALLOC
302 if (!attr->ignore_lockdep)
303 key = attr->key ?: (struct lock_class_key *)&attr->skey;
304#endif
305 kn = __kernfs_create_file(parent, attr->name, mode & 0777, size, ops,
306 (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
315int sysfs_add_file(struct kernfs_node *parent, const struct attribute *attr,
316 bool is_bin)
317{
318 return sysfs_add_file_mode_ns(parent, attr, is_bin, attr->mode, NULL);
319}
320
321/**
322 * sysfs_create_file_ns - create an attribute file for an object with custom ns
323 * @kobj: object we're creating for
324 * @attr: attribute descriptor
325 * @ns: namespace the new file should belong to
326 */
327int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
328 const void *ns)
329{
330 BUG_ON(!kobj || !kobj->sd || !attr);
331
332 return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode, ns);
333
334}
335EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
336
337int sysfs_create_files(struct kobject *kobj, const struct attribute **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 int error;
362
363 if (group) {
364 parent = kernfs_find_and_get(kobj->sd, group);
365 } else {
366 parent = kobj->sd;
367 kernfs_get(parent);
368 }
369
370 if (!parent)
371 return -ENOENT;
372
373 error = sysfs_add_file(parent, attr, false);
374 kernfs_put(parent);
375
376 return error;
377}
378EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
379
380/**
381 * sysfs_chmod_file - update the modified mode value on an object attribute.
382 * @kobj: object we're acting for.
383 * @attr: attribute descriptor.
384 * @mode: file permissions.
385 *
386 */
387int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
388 umode_t mode)
389{
390 struct kernfs_node *kn;
391 struct iattr newattrs;
392 int rc;
393
394 kn = kernfs_find_and_get(kobj->sd, attr->name);
395 if (!kn)
396 return -ENOENT;
397
398 newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
399 newattrs.ia_valid = ATTR_MODE;
400
401 rc = kernfs_setattr(kn, &newattrs);
402
403 kernfs_put(kn);
404 return rc;
405}
406EXPORT_SYMBOL_GPL(sysfs_chmod_file);
407
408/**
409 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
410 * @kobj: object we're acting for
411 * @attr: attribute descriptor
412 * @ns: namespace tag of the file to remove
413 *
414 * Hash the attribute name and namespace tag and kill the victim.
415 */
416void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
417 const void *ns)
418{
419 struct kernfs_node *parent = kobj->sd;
420
421 kernfs_remove_by_name_ns(parent, attr->name, ns);
422}
423EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
424
425/**
426 * sysfs_remove_file_self - remove an object attribute from its own method
427 * @kobj: object we're acting for
428 * @attr: attribute descriptor
429 *
430 * See kernfs_remove_self() for details.
431 */
432bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
433{
434 struct kernfs_node *parent = kobj->sd;
435 struct kernfs_node *kn;
436 bool ret;
437
438 kn = kernfs_find_and_get(parent, attr->name);
439 if (WARN_ON_ONCE(!kn))
440 return false;
441
442 ret = kernfs_remove_self(kn);
443
444 kernfs_put(kn);
445 return ret;
446}
447
448void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
449{
450 int i;
451 for (i = 0; ptr[i]; i++)
452 sysfs_remove_file(kobj, ptr[i]);
453}
454EXPORT_SYMBOL_GPL(sysfs_remove_files);
455
456/**
457 * sysfs_remove_file_from_group - remove an attribute file from a group.
458 * @kobj: object we're acting for.
459 * @attr: attribute descriptor.
460 * @group: group name.
461 */
462void sysfs_remove_file_from_group(struct kobject *kobj,
463 const struct attribute *attr, const char *group)
464{
465 struct kernfs_node *parent;
466
467 if (group) {
468 parent = kernfs_find_and_get(kobj->sd, group);
469 } else {
470 parent = kobj->sd;
471 kernfs_get(parent);
472 }
473
474 if (parent) {
475 kernfs_remove_by_name(parent, attr->name);
476 kernfs_put(parent);
477 }
478}
479EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
480
481/**
482 * sysfs_create_bin_file - create binary file for object.
483 * @kobj: object.
484 * @attr: attribute descriptor.
485 */
486int sysfs_create_bin_file(struct kobject *kobj,
487 const struct bin_attribute *attr)
488{
489 BUG_ON(!kobj || !kobj->sd || !attr);
490
491 return sysfs_add_file(kobj->sd, &attr->attr, true);
492}
493EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
494
495/**
496 * sysfs_remove_bin_file - remove binary file for object.
497 * @kobj: object.
498 * @attr: attribute descriptor.
499 */
500void sysfs_remove_bin_file(struct kobject *kobj,
501 const struct bin_attribute *attr)
502{
503 kernfs_remove_by_name(kobj->sd, attr->attr.name);
504}
505EXPORT_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.rst 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#include <linux/mm.h>
19
20#include "sysfs.h"
21
22/*
23 * Determine ktype->sysfs_ops for the given kernfs_node. This function
24 * must be called while holding an active reference.
25 */
26static const struct sysfs_ops *sysfs_file_ops(struct kernfs_node *kn)
27{
28 struct kobject *kobj = kn->parent->priv;
29
30 if (kn->flags & KERNFS_LOCKDEP)
31 lockdep_assert_held(kn);
32 return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
33}
34
35/*
36 * Reads on sysfs are handled through seq_file, which takes care of hairy
37 * details like buffering and seeking. The following function pipes
38 * sysfs_ops->show() result through seq_file.
39 */
40static int sysfs_kf_seq_show(struct seq_file *sf, void *v)
41{
42 struct kernfs_open_file *of = sf->private;
43 struct kobject *kobj = of->kn->parent->priv;
44 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
45 ssize_t count;
46 char *buf;
47
48 if (WARN_ON_ONCE(!ops->show))
49 return -EINVAL;
50
51 /* acquire buffer and ensure that it's >= PAGE_SIZE and clear */
52 count = seq_get_buf(sf, &buf);
53 if (count < PAGE_SIZE) {
54 seq_commit(sf, -1);
55 return 0;
56 }
57 memset(buf, 0, PAGE_SIZE);
58
59 count = ops->show(kobj, of->kn->priv, buf);
60 if (count < 0)
61 return count;
62
63 /*
64 * The code works fine with PAGE_SIZE return but it's likely to
65 * indicate truncated result or overflow in normal use cases.
66 */
67 if (count >= (ssize_t)PAGE_SIZE) {
68 printk("fill_read_buffer: %pS returned bad count\n",
69 ops->show);
70 /* Try to struggle along */
71 count = PAGE_SIZE - 1;
72 }
73 seq_commit(sf, count);
74 return 0;
75}
76
77static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
78 size_t count, loff_t pos)
79{
80 struct bin_attribute *battr = of->kn->priv;
81 struct kobject *kobj = of->kn->parent->priv;
82 loff_t size = file_inode(of->file)->i_size;
83
84 if (!count)
85 return 0;
86
87 if (size) {
88 if (pos >= size)
89 return 0;
90 if (pos + count > size)
91 count = size - pos;
92 }
93
94 if (!battr->read && !battr->read_new)
95 return -EIO;
96
97 if (battr->read_new)
98 return battr->read_new(of->file, kobj, battr, buf, pos, count);
99
100 return battr->read(of->file, kobj, battr, buf, pos, count);
101}
102
103/* kernfs read callback for regular sysfs files with pre-alloc */
104static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
105 size_t count, loff_t pos)
106{
107 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
108 struct kobject *kobj = of->kn->parent->priv;
109 ssize_t len;
110
111 /*
112 * If buf != of->prealloc_buf, we don't know how
113 * large it is, so cannot safely pass it to ->show
114 */
115 if (WARN_ON_ONCE(buf != of->prealloc_buf))
116 return 0;
117 len = ops->show(kobj, of->kn->priv, buf);
118 if (len < 0)
119 return len;
120 if (pos) {
121 if (len <= pos)
122 return 0;
123 len -= pos;
124 memmove(buf, buf + pos, len);
125 }
126 return min_t(ssize_t, count, len);
127}
128
129/* kernfs write callback for regular sysfs files */
130static ssize_t sysfs_kf_write(struct kernfs_open_file *of, char *buf,
131 size_t count, loff_t pos)
132{
133 const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
134 struct kobject *kobj = of->kn->parent->priv;
135
136 if (!count)
137 return 0;
138
139 return ops->store(kobj, of->kn->priv, buf, count);
140}
141
142/* kernfs write callback for bin sysfs files */
143static ssize_t sysfs_kf_bin_write(struct kernfs_open_file *of, char *buf,
144 size_t count, loff_t pos)
145{
146 struct bin_attribute *battr = of->kn->priv;
147 struct kobject *kobj = of->kn->parent->priv;
148 loff_t size = file_inode(of->file)->i_size;
149
150 if (size) {
151 if (size <= pos)
152 return -EFBIG;
153 count = min_t(ssize_t, count, size - pos);
154 }
155 if (!count)
156 return 0;
157
158 if (!battr->write && !battr->write_new)
159 return -EIO;
160
161 if (battr->write_new)
162 return battr->write_new(of->file, kobj, battr, buf, pos, count);
163
164 return battr->write(of->file, kobj, battr, buf, pos, count);
165}
166
167static int sysfs_kf_bin_mmap(struct kernfs_open_file *of,
168 struct vm_area_struct *vma)
169{
170 struct bin_attribute *battr = of->kn->priv;
171 struct kobject *kobj = of->kn->parent->priv;
172
173 return battr->mmap(of->file, kobj, battr, vma);
174}
175
176static loff_t sysfs_kf_bin_llseek(struct kernfs_open_file *of, loff_t offset,
177 int whence)
178{
179 struct bin_attribute *battr = of->kn->priv;
180 struct kobject *kobj = of->kn->parent->priv;
181
182 if (battr->llseek)
183 return battr->llseek(of->file, kobj, battr, offset, whence);
184 else
185 return generic_file_llseek(of->file, offset, whence);
186}
187
188static int sysfs_kf_bin_open(struct kernfs_open_file *of)
189{
190 struct bin_attribute *battr = of->kn->priv;
191
192 if (battr->f_mapping)
193 of->file->f_mapping = battr->f_mapping();
194
195 return 0;
196}
197
198void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
199{
200 struct kernfs_node *kn = kobj->sd, *tmp;
201
202 if (kn && dir)
203 kn = kernfs_find_and_get(kn, dir);
204 else
205 kernfs_get(kn);
206
207 if (kn && attr) {
208 tmp = kernfs_find_and_get(kn, attr);
209 kernfs_put(kn);
210 kn = tmp;
211 }
212
213 if (kn) {
214 kernfs_notify(kn);
215 kernfs_put(kn);
216 }
217}
218EXPORT_SYMBOL_GPL(sysfs_notify);
219
220static const struct kernfs_ops sysfs_file_kfops_empty = {
221};
222
223static const struct kernfs_ops sysfs_file_kfops_ro = {
224 .seq_show = sysfs_kf_seq_show,
225};
226
227static const struct kernfs_ops sysfs_file_kfops_wo = {
228 .write = sysfs_kf_write,
229};
230
231static const struct kernfs_ops sysfs_file_kfops_rw = {
232 .seq_show = sysfs_kf_seq_show,
233 .write = sysfs_kf_write,
234};
235
236static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
237 .read = sysfs_kf_read,
238 .prealloc = true,
239};
240
241static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
242 .write = sysfs_kf_write,
243 .prealloc = true,
244};
245
246static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
247 .read = sysfs_kf_read,
248 .write = sysfs_kf_write,
249 .prealloc = true,
250};
251
252static const struct kernfs_ops sysfs_bin_kfops_ro = {
253 .read = sysfs_kf_bin_read,
254};
255
256static const struct kernfs_ops sysfs_bin_kfops_wo = {
257 .write = sysfs_kf_bin_write,
258};
259
260static const struct kernfs_ops sysfs_bin_kfops_rw = {
261 .read = sysfs_kf_bin_read,
262 .write = sysfs_kf_bin_write,
263};
264
265static const struct kernfs_ops sysfs_bin_kfops_mmap = {
266 .read = sysfs_kf_bin_read,
267 .write = sysfs_kf_bin_write,
268 .mmap = sysfs_kf_bin_mmap,
269 .open = sysfs_kf_bin_open,
270 .llseek = sysfs_kf_bin_llseek,
271};
272
273int sysfs_add_file_mode_ns(struct kernfs_node *parent,
274 const struct attribute *attr, umode_t mode, kuid_t uid,
275 kgid_t gid, const void *ns)
276{
277 struct kobject *kobj = parent->priv;
278 const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
279 struct lock_class_key *key = NULL;
280 const struct kernfs_ops *ops = NULL;
281 struct kernfs_node *kn;
282
283 /* every kobject with an attribute needs a ktype assigned */
284 if (WARN(!sysfs_ops, KERN_ERR
285 "missing sysfs attribute operations for kobject: %s\n",
286 kobject_name(kobj)))
287 return -EINVAL;
288
289 if (mode & SYSFS_PREALLOC) {
290 if (sysfs_ops->show && sysfs_ops->store)
291 ops = &sysfs_prealloc_kfops_rw;
292 else if (sysfs_ops->show)
293 ops = &sysfs_prealloc_kfops_ro;
294 else if (sysfs_ops->store)
295 ops = &sysfs_prealloc_kfops_wo;
296 } else {
297 if (sysfs_ops->show && sysfs_ops->store)
298 ops = &sysfs_file_kfops_rw;
299 else if (sysfs_ops->show)
300 ops = &sysfs_file_kfops_ro;
301 else if (sysfs_ops->store)
302 ops = &sysfs_file_kfops_wo;
303 }
304
305 if (!ops)
306 ops = &sysfs_file_kfops_empty;
307
308#ifdef CONFIG_DEBUG_LOCK_ALLOC
309 if (!attr->ignore_lockdep)
310 key = attr->key ?: (struct lock_class_key *)&attr->skey;
311#endif
312
313 kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
314 PAGE_SIZE, ops, (void *)attr, ns, key);
315 if (IS_ERR(kn)) {
316 if (PTR_ERR(kn) == -EEXIST)
317 sysfs_warn_dup(parent, attr->name);
318 return PTR_ERR(kn);
319 }
320 return 0;
321}
322
323int sysfs_add_bin_file_mode_ns(struct kernfs_node *parent,
324 const struct bin_attribute *battr, umode_t mode, size_t size,
325 kuid_t uid, kgid_t gid, const void *ns)
326{
327 const struct attribute *attr = &battr->attr;
328 struct lock_class_key *key = NULL;
329 const struct kernfs_ops *ops;
330 struct kernfs_node *kn;
331
332 if (battr->read && battr->read_new)
333 return -EINVAL;
334
335 if (battr->write && battr->write_new)
336 return -EINVAL;
337
338 if (battr->mmap)
339 ops = &sysfs_bin_kfops_mmap;
340 else if ((battr->read || battr->read_new) && (battr->write || battr->write_new))
341 ops = &sysfs_bin_kfops_rw;
342 else if (battr->read || battr->read_new)
343 ops = &sysfs_bin_kfops_ro;
344 else if (battr->write || battr->write_new)
345 ops = &sysfs_bin_kfops_wo;
346 else
347 ops = &sysfs_file_kfops_empty;
348
349#ifdef CONFIG_DEBUG_LOCK_ALLOC
350 if (!attr->ignore_lockdep)
351 key = attr->key ?: (struct lock_class_key *)&attr->skey;
352#endif
353
354 kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
355 size, ops, (void *)attr, ns, key);
356 if (IS_ERR(kn)) {
357 if (PTR_ERR(kn) == -EEXIST)
358 sysfs_warn_dup(parent, attr->name);
359 return PTR_ERR(kn);
360 }
361 return 0;
362}
363
364/**
365 * sysfs_create_file_ns - create an attribute file for an object with custom ns
366 * @kobj: object we're creating for
367 * @attr: attribute descriptor
368 * @ns: namespace the new file should belong to
369 */
370int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
371 const void *ns)
372{
373 kuid_t uid;
374 kgid_t gid;
375
376 if (WARN_ON(!kobj || !kobj->sd || !attr))
377 return -EINVAL;
378
379 kobject_get_ownership(kobj, &uid, &gid);
380 return sysfs_add_file_mode_ns(kobj->sd, attr, attr->mode, uid, gid, ns);
381}
382EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
383
384int sysfs_create_files(struct kobject *kobj, const struct attribute * const *ptr)
385{
386 int err = 0;
387 int i;
388
389 for (i = 0; ptr[i] && !err; i++)
390 err = sysfs_create_file(kobj, ptr[i]);
391 if (err)
392 while (--i >= 0)
393 sysfs_remove_file(kobj, ptr[i]);
394 return err;
395}
396EXPORT_SYMBOL_GPL(sysfs_create_files);
397
398/**
399 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
400 * @kobj: object we're acting for.
401 * @attr: attribute descriptor.
402 * @group: group name.
403 */
404int sysfs_add_file_to_group(struct kobject *kobj,
405 const struct attribute *attr, const char *group)
406{
407 struct kernfs_node *parent;
408 kuid_t uid;
409 kgid_t gid;
410 int error;
411
412 if (group) {
413 parent = kernfs_find_and_get(kobj->sd, group);
414 } else {
415 parent = kobj->sd;
416 kernfs_get(parent);
417 }
418
419 if (!parent)
420 return -ENOENT;
421
422 kobject_get_ownership(kobj, &uid, &gid);
423 error = sysfs_add_file_mode_ns(parent, attr, attr->mode, uid, gid,
424 NULL);
425 kernfs_put(parent);
426
427 return error;
428}
429EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
430
431/**
432 * sysfs_chmod_file - update the modified mode value on an object attribute.
433 * @kobj: object we're acting for.
434 * @attr: attribute descriptor.
435 * @mode: file permissions.
436 *
437 */
438int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
439 umode_t mode)
440{
441 struct kernfs_node *kn;
442 struct iattr newattrs;
443 int rc;
444
445 kn = kernfs_find_and_get(kobj->sd, attr->name);
446 if (!kn)
447 return -ENOENT;
448
449 newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
450 newattrs.ia_valid = ATTR_MODE;
451
452 rc = kernfs_setattr(kn, &newattrs);
453
454 kernfs_put(kn);
455 return rc;
456}
457EXPORT_SYMBOL_GPL(sysfs_chmod_file);
458
459/**
460 * sysfs_break_active_protection - break "active" protection
461 * @kobj: The kernel object @attr is associated with.
462 * @attr: The attribute to break the "active" protection for.
463 *
464 * With sysfs, just like kernfs, deletion of an attribute is postponed until
465 * all active .show() and .store() callbacks have finished unless this function
466 * is called. Hence this function is useful in methods that implement self
467 * deletion.
468 */
469struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj,
470 const struct attribute *attr)
471{
472 struct kernfs_node *kn;
473
474 kobject_get(kobj);
475 kn = kernfs_find_and_get(kobj->sd, attr->name);
476 if (kn)
477 kernfs_break_active_protection(kn);
478 else
479 kobject_put(kobj);
480 return kn;
481}
482EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
483
484/**
485 * sysfs_unbreak_active_protection - restore "active" protection
486 * @kn: Pointer returned by sysfs_break_active_protection().
487 *
488 * Undo the effects of sysfs_break_active_protection(). Since this function
489 * calls kernfs_put() on the kernfs node that corresponds to the 'attr'
490 * argument passed to sysfs_break_active_protection() that attribute may have
491 * been removed between the sysfs_break_active_protection() and
492 * sysfs_unbreak_active_protection() calls, it is not safe to access @kn after
493 * this function has returned.
494 */
495void sysfs_unbreak_active_protection(struct kernfs_node *kn)
496{
497 struct kobject *kobj = kn->parent->priv;
498
499 kernfs_unbreak_active_protection(kn);
500 kernfs_put(kn);
501 kobject_put(kobj);
502}
503EXPORT_SYMBOL_GPL(sysfs_unbreak_active_protection);
504
505/**
506 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
507 * @kobj: object we're acting for
508 * @attr: attribute descriptor
509 * @ns: namespace tag of the file to remove
510 *
511 * Hash the attribute name and namespace tag and kill the victim.
512 */
513void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
514 const void *ns)
515{
516 struct kernfs_node *parent = kobj->sd;
517
518 kernfs_remove_by_name_ns(parent, attr->name, ns);
519}
520EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
521
522/**
523 * sysfs_remove_file_self - remove an object attribute from its own method
524 * @kobj: object we're acting for
525 * @attr: attribute descriptor
526 *
527 * See kernfs_remove_self() for details.
528 */
529bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
530{
531 struct kernfs_node *parent = kobj->sd;
532 struct kernfs_node *kn;
533 bool ret;
534
535 kn = kernfs_find_and_get(parent, attr->name);
536 if (WARN_ON_ONCE(!kn))
537 return false;
538
539 ret = kernfs_remove_self(kn);
540
541 kernfs_put(kn);
542 return ret;
543}
544EXPORT_SYMBOL_GPL(sysfs_remove_file_self);
545
546void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr)
547{
548 int i;
549
550 for (i = 0; ptr[i]; i++)
551 sysfs_remove_file(kobj, ptr[i]);
552}
553EXPORT_SYMBOL_GPL(sysfs_remove_files);
554
555/**
556 * sysfs_remove_file_from_group - remove an attribute file from a group.
557 * @kobj: object we're acting for.
558 * @attr: attribute descriptor.
559 * @group: group name.
560 */
561void sysfs_remove_file_from_group(struct kobject *kobj,
562 const struct attribute *attr, const char *group)
563{
564 struct kernfs_node *parent;
565
566 if (group) {
567 parent = kernfs_find_and_get(kobj->sd, group);
568 } else {
569 parent = kobj->sd;
570 kernfs_get(parent);
571 }
572
573 if (parent) {
574 kernfs_remove_by_name(parent, attr->name);
575 kernfs_put(parent);
576 }
577}
578EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
579
580/**
581 * sysfs_create_bin_file - create binary file for object.
582 * @kobj: object.
583 * @attr: attribute descriptor.
584 */
585int sysfs_create_bin_file(struct kobject *kobj,
586 const struct bin_attribute *attr)
587{
588 kuid_t uid;
589 kgid_t gid;
590
591 if (WARN_ON(!kobj || !kobj->sd || !attr))
592 return -EINVAL;
593
594 kobject_get_ownership(kobj, &uid, &gid);
595 return sysfs_add_bin_file_mode_ns(kobj->sd, attr, attr->attr.mode,
596 attr->size, uid, gid, NULL);
597}
598EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
599
600/**
601 * sysfs_remove_bin_file - remove binary file for object.
602 * @kobj: object.
603 * @attr: attribute descriptor.
604 */
605void sysfs_remove_bin_file(struct kobject *kobj,
606 const struct bin_attribute *attr)
607{
608 kernfs_remove_by_name(kobj->sd, attr->attr.name);
609}
610EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
611
612static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid,
613 kgid_t kgid)
614{
615 struct iattr newattrs = {
616 .ia_valid = ATTR_UID | ATTR_GID,
617 .ia_uid = kuid,
618 .ia_gid = kgid,
619 };
620 return kernfs_setattr(kn, &newattrs);
621}
622
623/**
624 * sysfs_link_change_owner - change owner of a sysfs file.
625 * @kobj: object of the kernfs_node the symlink is located in.
626 * @targ: object of the kernfs_node the symlink points to.
627 * @name: name of the link.
628 * @kuid: new owner's kuid
629 * @kgid: new owner's kgid
630 *
631 * This function looks up the sysfs symlink entry @name under @kobj and changes
632 * the ownership to @kuid/@kgid. The symlink is looked up in the namespace of
633 * @targ.
634 *
635 * Returns 0 on success or error code on failure.
636 */
637int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ,
638 const char *name, kuid_t kuid, kgid_t kgid)
639{
640 struct kernfs_node *kn = NULL;
641 int error;
642
643 if (!name || !kobj->state_in_sysfs || !targ->state_in_sysfs)
644 return -EINVAL;
645
646 error = -ENOENT;
647 kn = kernfs_find_and_get_ns(kobj->sd, name, targ->sd->ns);
648 if (!kn)
649 goto out;
650
651 error = -EINVAL;
652 if (kernfs_type(kn) != KERNFS_LINK)
653 goto out;
654 if (kn->symlink.target_kn->priv != targ)
655 goto out;
656
657 error = internal_change_owner(kn, kuid, kgid);
658
659out:
660 kernfs_put(kn);
661 return error;
662}
663
664/**
665 * sysfs_file_change_owner - change owner of a sysfs file.
666 * @kobj: object.
667 * @name: name of the file to change.
668 * @kuid: new owner's kuid
669 * @kgid: new owner's kgid
670 *
671 * This function looks up the sysfs entry @name under @kobj and changes the
672 * ownership to @kuid/@kgid.
673 *
674 * Returns 0 on success or error code on failure.
675 */
676int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid,
677 kgid_t kgid)
678{
679 struct kernfs_node *kn;
680 int error;
681
682 if (!name)
683 return -EINVAL;
684
685 if (!kobj->state_in_sysfs)
686 return -EINVAL;
687
688 kn = kernfs_find_and_get(kobj->sd, name);
689 if (!kn)
690 return -ENOENT;
691
692 error = internal_change_owner(kn, kuid, kgid);
693
694 kernfs_put(kn);
695
696 return error;
697}
698EXPORT_SYMBOL_GPL(sysfs_file_change_owner);
699
700/**
701 * sysfs_change_owner - change owner of the given object.
702 * @kobj: object.
703 * @kuid: new owner's kuid
704 * @kgid: new owner's kgid
705 *
706 * Change the owner of the default directory, files, groups, and attributes of
707 * @kobj to @kuid/@kgid. Note that sysfs_change_owner mirrors how the sysfs
708 * entries for a kobject are added by driver core. In summary,
709 * sysfs_change_owner() takes care of the default directory entry for @kobj,
710 * the default attributes associated with the ktype of @kobj and the default
711 * attributes associated with the ktype of @kobj.
712 * Additional properties not added by driver core have to be changed by the
713 * driver or subsystem which created them. This is similar to how
714 * driver/subsystem specific entries are removed.
715 *
716 * Returns 0 on success or error code on failure.
717 */
718int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid)
719{
720 int error;
721 const struct kobj_type *ktype;
722
723 if (!kobj->state_in_sysfs)
724 return -EINVAL;
725
726 /* Change the owner of the kobject itself. */
727 error = internal_change_owner(kobj->sd, kuid, kgid);
728 if (error)
729 return error;
730
731 ktype = get_ktype(kobj);
732 if (ktype) {
733 /*
734 * Change owner of the default groups associated with the
735 * ktype of @kobj.
736 */
737 error = sysfs_groups_change_owner(kobj, ktype->default_groups,
738 kuid, kgid);
739 if (error)
740 return error;
741 }
742
743 return 0;
744}
745EXPORT_SYMBOL_GPL(sysfs_change_owner);
746
747/**
748 * sysfs_emit - scnprintf equivalent, aware of PAGE_SIZE buffer.
749 * @buf: start of PAGE_SIZE buffer.
750 * @fmt: format
751 * @...: optional arguments to @format
752 *
753 *
754 * Returns number of characters written to @buf.
755 */
756int sysfs_emit(char *buf, const char *fmt, ...)
757{
758 va_list args;
759 int len;
760
761 if (WARN(!buf || offset_in_page(buf),
762 "invalid sysfs_emit: buf:%p\n", buf))
763 return 0;
764
765 va_start(args, fmt);
766 len = vscnprintf(buf, PAGE_SIZE, fmt, args);
767 va_end(args);
768
769 return len;
770}
771EXPORT_SYMBOL_GPL(sysfs_emit);
772
773/**
774 * sysfs_emit_at - scnprintf equivalent, aware of PAGE_SIZE buffer.
775 * @buf: start of PAGE_SIZE buffer.
776 * @at: offset in @buf to start write in bytes
777 * @at must be >= 0 && < PAGE_SIZE
778 * @fmt: format
779 * @...: optional arguments to @fmt
780 *
781 *
782 * Returns number of characters written starting at &@buf[@at].
783 */
784int sysfs_emit_at(char *buf, int at, const char *fmt, ...)
785{
786 va_list args;
787 int len;
788
789 if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE,
790 "invalid sysfs_emit_at: buf:%p at:%d\n", buf, at))
791 return 0;
792
793 va_start(args, fmt);
794 len = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
795 va_end(args);
796
797 return len;
798}
799EXPORT_SYMBOL_GPL(sysfs_emit_at);
800
801/**
802 * sysfs_bin_attr_simple_read - read callback to simply copy from memory.
803 * @file: attribute file which is being read.
804 * @kobj: object to which the attribute belongs.
805 * @attr: attribute descriptor.
806 * @buf: destination buffer.
807 * @off: offset in bytes from which to read.
808 * @count: maximum number of bytes to read.
809 *
810 * Simple ->read() callback for bin_attributes backed by a buffer in memory.
811 * The @private and @size members in struct bin_attribute must be set to the
812 * buffer's location and size before the bin_attribute is created in sysfs.
813 *
814 * Bounds check for @off and @count is done in sysfs_kf_bin_read().
815 * Negative value check for @off is done in vfs_setpos() and default_llseek().
816 *
817 * Returns number of bytes written to @buf.
818 */
819ssize_t sysfs_bin_attr_simple_read(struct file *file, struct kobject *kobj,
820 struct bin_attribute *attr, char *buf,
821 loff_t off, size_t count)
822{
823 memcpy(buf, attr->private + off, count);
824 return count;
825}
826EXPORT_SYMBOL_GPL(sysfs_bin_attr_simple_read);