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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 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);
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 /* 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
173static int sysfs_kf_bin_open(struct kernfs_open_file *of)
174{
175 struct bin_attribute *battr = of->kn->priv;
176
177 if (battr->mapping)
178 of->file->f_mapping = battr->mapping;
179
180 return 0;
181}
182
183void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr)
184{
185 struct kernfs_node *kn = kobj->sd, *tmp;
186
187 if (kn && dir)
188 kn = kernfs_find_and_get(kn, dir);
189 else
190 kernfs_get(kn);
191
192 if (kn && attr) {
193 tmp = kernfs_find_and_get(kn, attr);
194 kernfs_put(kn);
195 kn = tmp;
196 }
197
198 if (kn) {
199 kernfs_notify(kn);
200 kernfs_put(kn);
201 }
202}
203EXPORT_SYMBOL_GPL(sysfs_notify);
204
205static const struct kernfs_ops sysfs_file_kfops_empty = {
206};
207
208static const struct kernfs_ops sysfs_file_kfops_ro = {
209 .seq_show = sysfs_kf_seq_show,
210};
211
212static const struct kernfs_ops sysfs_file_kfops_wo = {
213 .write = sysfs_kf_write,
214};
215
216static const struct kernfs_ops sysfs_file_kfops_rw = {
217 .seq_show = sysfs_kf_seq_show,
218 .write = sysfs_kf_write,
219};
220
221static const struct kernfs_ops sysfs_prealloc_kfops_ro = {
222 .read = sysfs_kf_read,
223 .prealloc = true,
224};
225
226static const struct kernfs_ops sysfs_prealloc_kfops_wo = {
227 .write = sysfs_kf_write,
228 .prealloc = true,
229};
230
231static const struct kernfs_ops sysfs_prealloc_kfops_rw = {
232 .read = sysfs_kf_read,
233 .write = sysfs_kf_write,
234 .prealloc = true,
235};
236
237static const struct kernfs_ops sysfs_bin_kfops_ro = {
238 .read = sysfs_kf_bin_read,
239};
240
241static const struct kernfs_ops sysfs_bin_kfops_wo = {
242 .write = sysfs_kf_bin_write,
243};
244
245static const struct kernfs_ops sysfs_bin_kfops_rw = {
246 .read = sysfs_kf_bin_read,
247 .write = sysfs_kf_bin_write,
248};
249
250static const struct kernfs_ops sysfs_bin_kfops_mmap = {
251 .read = sysfs_kf_bin_read,
252 .write = sysfs_kf_bin_write,
253 .mmap = sysfs_kf_bin_mmap,
254 .open = sysfs_kf_bin_open,
255};
256
257int sysfs_add_file_mode_ns(struct kernfs_node *parent,
258 const struct attribute *attr, bool is_bin,
259 umode_t mode, kuid_t uid, kgid_t gid, const void *ns)
260{
261 struct lock_class_key *key = NULL;
262 const struct kernfs_ops *ops;
263 struct kernfs_node *kn;
264 loff_t size;
265
266 if (!is_bin) {
267 struct kobject *kobj = parent->priv;
268 const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops;
269
270 /* every kobject with an attribute needs a ktype assigned */
271 if (WARN(!sysfs_ops, KERN_ERR
272 "missing sysfs attribute operations for kobject: %s\n",
273 kobject_name(kobj)))
274 return -EINVAL;
275
276 if (sysfs_ops->show && sysfs_ops->store) {
277 if (mode & SYSFS_PREALLOC)
278 ops = &sysfs_prealloc_kfops_rw;
279 else
280 ops = &sysfs_file_kfops_rw;
281 } else if (sysfs_ops->show) {
282 if (mode & SYSFS_PREALLOC)
283 ops = &sysfs_prealloc_kfops_ro;
284 else
285 ops = &sysfs_file_kfops_ro;
286 } else if (sysfs_ops->store) {
287 if (mode & SYSFS_PREALLOC)
288 ops = &sysfs_prealloc_kfops_wo;
289 else
290 ops = &sysfs_file_kfops_wo;
291 } else
292 ops = &sysfs_file_kfops_empty;
293
294 size = PAGE_SIZE;
295 } else {
296 struct bin_attribute *battr = (void *)attr;
297
298 if (battr->mmap)
299 ops = &sysfs_bin_kfops_mmap;
300 else if (battr->read && battr->write)
301 ops = &sysfs_bin_kfops_rw;
302 else if (battr->read)
303 ops = &sysfs_bin_kfops_ro;
304 else if (battr->write)
305 ops = &sysfs_bin_kfops_wo;
306 else
307 ops = &sysfs_file_kfops_empty;
308
309 size = battr->size;
310 }
311
312#ifdef CONFIG_DEBUG_LOCK_ALLOC
313 if (!attr->ignore_lockdep)
314 key = attr->key ?: (struct lock_class_key *)&attr->skey;
315#endif
316
317 kn = __kernfs_create_file(parent, attr->name, mode & 0777, uid, gid,
318 size, ops, (void *)attr, ns, key);
319 if (IS_ERR(kn)) {
320 if (PTR_ERR(kn) == -EEXIST)
321 sysfs_warn_dup(parent, attr->name);
322 return PTR_ERR(kn);
323 }
324 return 0;
325}
326
327/**
328 * sysfs_create_file_ns - create an attribute file for an object with custom ns
329 * @kobj: object we're creating for
330 * @attr: attribute descriptor
331 * @ns: namespace the new file should belong to
332 */
333int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
334 const void *ns)
335{
336 kuid_t uid;
337 kgid_t gid;
338
339 if (WARN_ON(!kobj || !kobj->sd || !attr))
340 return -EINVAL;
341
342 kobject_get_ownership(kobj, &uid, &gid);
343 return sysfs_add_file_mode_ns(kobj->sd, attr, false, attr->mode,
344 uid, gid, ns);
345
346}
347EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
348
349int sysfs_create_files(struct kobject *kobj, const struct attribute * const *ptr)
350{
351 int err = 0;
352 int i;
353
354 for (i = 0; ptr[i] && !err; i++)
355 err = sysfs_create_file(kobj, ptr[i]);
356 if (err)
357 while (--i >= 0)
358 sysfs_remove_file(kobj, ptr[i]);
359 return err;
360}
361EXPORT_SYMBOL_GPL(sysfs_create_files);
362
363/**
364 * sysfs_add_file_to_group - add an attribute file to a pre-existing group.
365 * @kobj: object we're acting for.
366 * @attr: attribute descriptor.
367 * @group: group name.
368 */
369int sysfs_add_file_to_group(struct kobject *kobj,
370 const struct attribute *attr, const char *group)
371{
372 struct kernfs_node *parent;
373 kuid_t uid;
374 kgid_t gid;
375 int error;
376
377 if (group) {
378 parent = kernfs_find_and_get(kobj->sd, group);
379 } else {
380 parent = kobj->sd;
381 kernfs_get(parent);
382 }
383
384 if (!parent)
385 return -ENOENT;
386
387 kobject_get_ownership(kobj, &uid, &gid);
388 error = sysfs_add_file_mode_ns(parent, attr, false,
389 attr->mode, uid, gid, NULL);
390 kernfs_put(parent);
391
392 return error;
393}
394EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
395
396/**
397 * sysfs_chmod_file - update the modified mode value on an object attribute.
398 * @kobj: object we're acting for.
399 * @attr: attribute descriptor.
400 * @mode: file permissions.
401 *
402 */
403int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
404 umode_t mode)
405{
406 struct kernfs_node *kn;
407 struct iattr newattrs;
408 int rc;
409
410 kn = kernfs_find_and_get(kobj->sd, attr->name);
411 if (!kn)
412 return -ENOENT;
413
414 newattrs.ia_mode = (mode & S_IALLUGO) | (kn->mode & ~S_IALLUGO);
415 newattrs.ia_valid = ATTR_MODE;
416
417 rc = kernfs_setattr(kn, &newattrs);
418
419 kernfs_put(kn);
420 return rc;
421}
422EXPORT_SYMBOL_GPL(sysfs_chmod_file);
423
424/**
425 * sysfs_break_active_protection - break "active" protection
426 * @kobj: The kernel object @attr is associated with.
427 * @attr: The attribute to break the "active" protection for.
428 *
429 * With sysfs, just like kernfs, deletion of an attribute is postponed until
430 * all active .show() and .store() callbacks have finished unless this function
431 * is called. Hence this function is useful in methods that implement self
432 * deletion.
433 */
434struct kernfs_node *sysfs_break_active_protection(struct kobject *kobj,
435 const struct attribute *attr)
436{
437 struct kernfs_node *kn;
438
439 kobject_get(kobj);
440 kn = kernfs_find_and_get(kobj->sd, attr->name);
441 if (kn)
442 kernfs_break_active_protection(kn);
443 return kn;
444}
445EXPORT_SYMBOL_GPL(sysfs_break_active_protection);
446
447/**
448 * sysfs_unbreak_active_protection - restore "active" protection
449 * @kn: Pointer returned by sysfs_break_active_protection().
450 *
451 * Undo the effects of sysfs_break_active_protection(). Since this function
452 * calls kernfs_put() on the kernfs node that corresponds to the 'attr'
453 * argument passed to sysfs_break_active_protection() that attribute may have
454 * been removed between the sysfs_break_active_protection() and
455 * sysfs_unbreak_active_protection() calls, it is not safe to access @kn after
456 * this function has returned.
457 */
458void sysfs_unbreak_active_protection(struct kernfs_node *kn)
459{
460 struct kobject *kobj = kn->parent->priv;
461
462 kernfs_unbreak_active_protection(kn);
463 kernfs_put(kn);
464 kobject_put(kobj);
465}
466EXPORT_SYMBOL_GPL(sysfs_unbreak_active_protection);
467
468/**
469 * sysfs_remove_file_ns - remove an object attribute with a custom ns tag
470 * @kobj: object we're acting for
471 * @attr: attribute descriptor
472 * @ns: namespace tag of the file to remove
473 *
474 * Hash the attribute name and namespace tag and kill the victim.
475 */
476void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
477 const void *ns)
478{
479 struct kernfs_node *parent = kobj->sd;
480
481 kernfs_remove_by_name_ns(parent, attr->name, ns);
482}
483EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
484
485/**
486 * sysfs_remove_file_self - remove an object attribute from its own method
487 * @kobj: object we're acting for
488 * @attr: attribute descriptor
489 *
490 * See kernfs_remove_self() for details.
491 */
492bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
493{
494 struct kernfs_node *parent = kobj->sd;
495 struct kernfs_node *kn;
496 bool ret;
497
498 kn = kernfs_find_and_get(parent, attr->name);
499 if (WARN_ON_ONCE(!kn))
500 return false;
501
502 ret = kernfs_remove_self(kn);
503
504 kernfs_put(kn);
505 return ret;
506}
507EXPORT_SYMBOL_GPL(sysfs_remove_file_self);
508
509void sysfs_remove_files(struct kobject *kobj, const struct attribute * const *ptr)
510{
511 int i;
512
513 for (i = 0; ptr[i]; i++)
514 sysfs_remove_file(kobj, ptr[i]);
515}
516EXPORT_SYMBOL_GPL(sysfs_remove_files);
517
518/**
519 * sysfs_remove_file_from_group - remove an attribute file from a group.
520 * @kobj: object we're acting for.
521 * @attr: attribute descriptor.
522 * @group: group name.
523 */
524void sysfs_remove_file_from_group(struct kobject *kobj,
525 const struct attribute *attr, const char *group)
526{
527 struct kernfs_node *parent;
528
529 if (group) {
530 parent = kernfs_find_and_get(kobj->sd, group);
531 } else {
532 parent = kobj->sd;
533 kernfs_get(parent);
534 }
535
536 if (parent) {
537 kernfs_remove_by_name(parent, attr->name);
538 kernfs_put(parent);
539 }
540}
541EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
542
543/**
544 * sysfs_create_bin_file - create binary file for object.
545 * @kobj: object.
546 * @attr: attribute descriptor.
547 */
548int sysfs_create_bin_file(struct kobject *kobj,
549 const struct bin_attribute *attr)
550{
551 kuid_t uid;
552 kgid_t gid;
553
554 if (WARN_ON(!kobj || !kobj->sd || !attr))
555 return -EINVAL;
556
557 kobject_get_ownership(kobj, &uid, &gid);
558 return sysfs_add_file_mode_ns(kobj->sd, &attr->attr, true,
559 attr->attr.mode, uid, gid, NULL);
560}
561EXPORT_SYMBOL_GPL(sysfs_create_bin_file);
562
563/**
564 * sysfs_remove_bin_file - remove binary file for object.
565 * @kobj: object.
566 * @attr: attribute descriptor.
567 */
568void sysfs_remove_bin_file(struct kobject *kobj,
569 const struct bin_attribute *attr)
570{
571 kernfs_remove_by_name(kobj->sd, attr->attr.name);
572}
573EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
574
575static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid,
576 kgid_t kgid)
577{
578 struct iattr newattrs = {
579 .ia_valid = ATTR_UID | ATTR_GID,
580 .ia_uid = kuid,
581 .ia_gid = kgid,
582 };
583 return kernfs_setattr(kn, &newattrs);
584}
585
586/**
587 * sysfs_link_change_owner - change owner of a sysfs file.
588 * @kobj: object of the kernfs_node the symlink is located in.
589 * @targ: object of the kernfs_node the symlink points to.
590 * @name: name of the link.
591 * @kuid: new owner's kuid
592 * @kgid: new owner's kgid
593 *
594 * This function looks up the sysfs symlink entry @name under @kobj and changes
595 * the ownership to @kuid/@kgid. The symlink is looked up in the namespace of
596 * @targ.
597 *
598 * Returns 0 on success or error code on failure.
599 */
600int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ,
601 const char *name, kuid_t kuid, kgid_t kgid)
602{
603 struct kernfs_node *kn = NULL;
604 int error;
605
606 if (!name || !kobj->state_in_sysfs || !targ->state_in_sysfs)
607 return -EINVAL;
608
609 error = -ENOENT;
610 kn = kernfs_find_and_get_ns(kobj->sd, name, targ->sd->ns);
611 if (!kn)
612 goto out;
613
614 error = -EINVAL;
615 if (kernfs_type(kn) != KERNFS_LINK)
616 goto out;
617 if (kn->symlink.target_kn->priv != targ)
618 goto out;
619
620 error = internal_change_owner(kn, kuid, kgid);
621
622out:
623 kernfs_put(kn);
624 return error;
625}
626
627/**
628 * sysfs_file_change_owner - change owner of a sysfs file.
629 * @kobj: object.
630 * @name: name of the file to change.
631 * @kuid: new owner's kuid
632 * @kgid: new owner's kgid
633 *
634 * This function looks up the sysfs entry @name under @kobj and changes the
635 * ownership to @kuid/@kgid.
636 *
637 * Returns 0 on success or error code on failure.
638 */
639int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid,
640 kgid_t kgid)
641{
642 struct kernfs_node *kn;
643 int error;
644
645 if (!name)
646 return -EINVAL;
647
648 if (!kobj->state_in_sysfs)
649 return -EINVAL;
650
651 kn = kernfs_find_and_get(kobj->sd, name);
652 if (!kn)
653 return -ENOENT;
654
655 error = internal_change_owner(kn, kuid, kgid);
656
657 kernfs_put(kn);
658
659 return error;
660}
661EXPORT_SYMBOL_GPL(sysfs_file_change_owner);
662
663/**
664 * sysfs_change_owner - change owner of the given object.
665 * @kobj: object.
666 * @kuid: new owner's kuid
667 * @kgid: new owner's kgid
668 *
669 * Change the owner of the default directory, files, groups, and attributes of
670 * @kobj to @kuid/@kgid. Note that sysfs_change_owner mirrors how the sysfs
671 * entries for a kobject are added by driver core. In summary,
672 * sysfs_change_owner() takes care of the default directory entry for @kobj,
673 * the default attributes associated with the ktype of @kobj and the default
674 * attributes associated with the ktype of @kobj.
675 * Additional properties not added by driver core have to be changed by the
676 * driver or subsystem which created them. This is similar to how
677 * driver/subsystem specific entries are removed.
678 *
679 * Returns 0 on success or error code on failure.
680 */
681int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid)
682{
683 int error;
684 const struct kobj_type *ktype;
685
686 if (!kobj->state_in_sysfs)
687 return -EINVAL;
688
689 /* Change the owner of the kobject itself. */
690 error = internal_change_owner(kobj->sd, kuid, kgid);
691 if (error)
692 return error;
693
694 ktype = get_ktype(kobj);
695 if (ktype) {
696 struct attribute **kattr;
697
698 /*
699 * Change owner of the default attributes associated with the
700 * ktype of @kobj.
701 */
702 for (kattr = ktype->default_attrs; kattr && *kattr; kattr++) {
703 error = sysfs_file_change_owner(kobj, (*kattr)->name,
704 kuid, kgid);
705 if (error)
706 return error;
707 }
708
709 /*
710 * Change owner of the default groups associated with the
711 * ktype of @kobj.
712 */
713 error = sysfs_groups_change_owner(kobj, ktype->default_groups,
714 kuid, kgid);
715 if (error)
716 return error;
717 }
718
719 return 0;
720}
721EXPORT_SYMBOL_GPL(sysfs_change_owner);
722
723/**
724 * sysfs_emit - scnprintf equivalent, aware of PAGE_SIZE buffer.
725 * @buf: start of PAGE_SIZE buffer.
726 * @fmt: format
727 * @...: optional arguments to @format
728 *
729 *
730 * Returns number of characters written to @buf.
731 */
732int sysfs_emit(char *buf, const char *fmt, ...)
733{
734 va_list args;
735 int len;
736
737 if (WARN(!buf || offset_in_page(buf),
738 "invalid sysfs_emit: buf:%p\n", buf))
739 return 0;
740
741 va_start(args, fmt);
742 len = vscnprintf(buf, PAGE_SIZE, fmt, args);
743 va_end(args);
744
745 return len;
746}
747EXPORT_SYMBOL_GPL(sysfs_emit);
748
749/**
750 * sysfs_emit_at - scnprintf equivalent, aware of PAGE_SIZE buffer.
751 * @buf: start of PAGE_SIZE buffer.
752 * @at: offset in @buf to start write in bytes
753 * @at must be >= 0 && < PAGE_SIZE
754 * @fmt: format
755 * @...: optional arguments to @fmt
756 *
757 *
758 * Returns number of characters written starting at &@buf[@at].
759 */
760int sysfs_emit_at(char *buf, int at, const char *fmt, ...)
761{
762 va_list args;
763 int len;
764
765 if (WARN(!buf || offset_in_page(buf) || at < 0 || at >= PAGE_SIZE,
766 "invalid sysfs_emit_at: buf:%p at:%d\n", buf, at))
767 return 0;
768
769 va_start(args, fmt);
770 len = vscnprintf(buf + at, PAGE_SIZE - at, fmt, args);
771 va_end(args);
772
773 return len;
774}
775EXPORT_SYMBOL_GPL(sysfs_emit_at);