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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
24
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
37
38
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
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
58
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
68
69
70 if (count >= (ssize_t)PAGE_SIZE) {
71 printk("fill_read_buffer: %pS returned bad count\n",
72 ops->show);
73
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
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
113
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
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
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->f_mapping)
178 of->file->f_mapping = battr->f_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
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
329
330
331
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
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367
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);
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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);
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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
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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);
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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
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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
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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
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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
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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}
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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}
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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);
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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
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
700
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
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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);
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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);
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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);
776