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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
4 *
5 * Copyright (c) 2003 Patrick Mochel
6 * Copyright (c) 2003 Open Source Development Lab
7 * Copyright (c) 2013 Greg Kroah-Hartman
8 * Copyright (c) 2013 The Linux Foundation
9 */
10
11#include <linux/kobject.h>
12#include <linux/module.h>
13#include <linux/dcache.h>
14#include <linux/namei.h>
15#include <linux/err.h>
16#include <linux/fs.h>
17#include "sysfs.h"
18
19
20static void remove_files(struct kernfs_node *parent,
21 const struct attribute_group *grp)
22{
23 struct attribute *const *attr;
24 struct bin_attribute *const *bin_attr;
25
26 if (grp->attrs)
27 for (attr = grp->attrs; *attr; attr++)
28 kernfs_remove_by_name(parent, (*attr)->name);
29 if (grp->bin_attrs)
30 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
31 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
32}
33
34static umode_t __first_visible(const struct attribute_group *grp, struct kobject *kobj)
35{
36 if (grp->attrs && grp->attrs[0] && grp->is_visible)
37 return grp->is_visible(kobj, grp->attrs[0], 0);
38
39 if (grp->bin_attrs && grp->bin_attrs[0] && grp->is_bin_visible)
40 return grp->is_bin_visible(kobj, grp->bin_attrs[0], 0);
41
42 return 0;
43}
44
45static int create_files(struct kernfs_node *parent, struct kobject *kobj,
46 kuid_t uid, kgid_t gid,
47 const struct attribute_group *grp, int update)
48{
49 struct attribute *const *attr;
50 struct bin_attribute *const *bin_attr;
51 int error = 0, i;
52
53 if (grp->attrs) {
54 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
55 umode_t mode = (*attr)->mode;
56
57 /*
58 * In update mode, we're changing the permissions or
59 * visibility. Do this by first removing then
60 * re-adding (if required) the file.
61 */
62 if (update)
63 kernfs_remove_by_name(parent, (*attr)->name);
64 if (grp->is_visible) {
65 mode = grp->is_visible(kobj, *attr, i);
66 mode &= ~SYSFS_GROUP_INVISIBLE;
67 if (!mode)
68 continue;
69 }
70
71 WARN(mode & ~(SYSFS_PREALLOC | 0664),
72 "Attribute %s: Invalid permissions 0%o\n",
73 (*attr)->name, mode);
74
75 mode &= SYSFS_PREALLOC | 0664;
76 error = sysfs_add_file_mode_ns(parent, *attr, mode, uid,
77 gid, NULL);
78 if (unlikely(error))
79 break;
80 }
81 if (error) {
82 remove_files(parent, grp);
83 goto exit;
84 }
85 }
86
87 if (grp->bin_attrs) {
88 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
89 umode_t mode = (*bin_attr)->attr.mode;
90
91 if (update)
92 kernfs_remove_by_name(parent,
93 (*bin_attr)->attr.name);
94 if (grp->is_bin_visible) {
95 mode = grp->is_bin_visible(kobj, *bin_attr, i);
96 mode &= ~SYSFS_GROUP_INVISIBLE;
97 if (!mode)
98 continue;
99 }
100
101 WARN(mode & ~(SYSFS_PREALLOC | 0664),
102 "Attribute %s: Invalid permissions 0%o\n",
103 (*bin_attr)->attr.name, mode);
104
105 mode &= SYSFS_PREALLOC | 0664;
106 error = sysfs_add_bin_file_mode_ns(parent, *bin_attr,
107 mode, uid, gid,
108 NULL);
109 if (error)
110 break;
111 }
112 if (error)
113 remove_files(parent, grp);
114 }
115exit:
116 return error;
117}
118
119
120static int internal_create_group(struct kobject *kobj, int update,
121 const struct attribute_group *grp)
122{
123 struct kernfs_node *kn;
124 kuid_t uid;
125 kgid_t gid;
126 int error;
127
128 if (WARN_ON(!kobj || (!update && !kobj->sd)))
129 return -EINVAL;
130
131 /* Updates may happen before the object has been instantiated */
132 if (unlikely(update && !kobj->sd))
133 return -EINVAL;
134
135 if (!grp->attrs && !grp->bin_attrs) {
136 pr_debug("sysfs: (bin_)attrs not set by subsystem for group: %s/%s, skipping\n",
137 kobj->name, grp->name ?: "");
138 return 0;
139 }
140
141 kobject_get_ownership(kobj, &uid, &gid);
142 if (grp->name) {
143 umode_t mode = __first_visible(grp, kobj);
144
145 if (mode & SYSFS_GROUP_INVISIBLE)
146 mode = 0;
147 else
148 mode = S_IRWXU | S_IRUGO | S_IXUGO;
149
150 if (update) {
151 kn = kernfs_find_and_get(kobj->sd, grp->name);
152 if (!kn) {
153 pr_debug("attr grp %s/%s not created yet\n",
154 kobj->name, grp->name);
155 /* may have been invisible prior to this update */
156 update = 0;
157 } else if (!mode) {
158 sysfs_remove_group(kobj, grp);
159 kernfs_put(kn);
160 return 0;
161 }
162 }
163
164 if (!update) {
165 if (!mode)
166 return 0;
167 kn = kernfs_create_dir_ns(kobj->sd, grp->name, mode,
168 uid, gid, kobj, NULL);
169 if (IS_ERR(kn)) {
170 if (PTR_ERR(kn) == -EEXIST)
171 sysfs_warn_dup(kobj->sd, grp->name);
172 return PTR_ERR(kn);
173 }
174 }
175 } else {
176 kn = kobj->sd;
177 }
178
179 kernfs_get(kn);
180 error = create_files(kn, kobj, uid, gid, grp, update);
181 if (error) {
182 if (grp->name)
183 kernfs_remove(kn);
184 }
185 kernfs_put(kn);
186
187 if (grp->name && update)
188 kernfs_put(kn);
189
190 return error;
191}
192
193/**
194 * sysfs_create_group - given a directory kobject, create an attribute group
195 * @kobj: The kobject to create the group on
196 * @grp: The attribute group to create
197 *
198 * This function creates a group for the first time. It will explicitly
199 * warn and error if any of the attribute files being created already exist.
200 *
201 * Returns 0 on success or error code on failure.
202 */
203int sysfs_create_group(struct kobject *kobj,
204 const struct attribute_group *grp)
205{
206 return internal_create_group(kobj, 0, grp);
207}
208EXPORT_SYMBOL_GPL(sysfs_create_group);
209
210static int internal_create_groups(struct kobject *kobj, int update,
211 const struct attribute_group **groups)
212{
213 int error = 0;
214 int i;
215
216 if (!groups)
217 return 0;
218
219 for (i = 0; groups[i]; i++) {
220 error = internal_create_group(kobj, update, groups[i]);
221 if (error) {
222 while (--i >= 0)
223 sysfs_remove_group(kobj, groups[i]);
224 break;
225 }
226 }
227 return error;
228}
229
230/**
231 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
232 * @kobj: The kobject to create the group on
233 * @groups: The attribute groups to create, NULL terminated
234 *
235 * This function creates a bunch of attribute groups. If an error occurs when
236 * creating a group, all previously created groups will be removed, unwinding
237 * everything back to the original state when this function was called.
238 * It will explicitly warn and error if any of the attribute files being
239 * created already exist.
240 *
241 * Returns 0 on success or error code from sysfs_create_group on failure.
242 */
243int sysfs_create_groups(struct kobject *kobj,
244 const struct attribute_group **groups)
245{
246 return internal_create_groups(kobj, 0, groups);
247}
248EXPORT_SYMBOL_GPL(sysfs_create_groups);
249
250/**
251 * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
252 * @kobj: The kobject to update the group on
253 * @groups: The attribute groups to update, NULL terminated
254 *
255 * This function update a bunch of attribute groups. If an error occurs when
256 * updating a group, all previously updated groups will be removed together
257 * with already existing (not updated) attributes.
258 *
259 * Returns 0 on success or error code from sysfs_update_group on failure.
260 */
261int sysfs_update_groups(struct kobject *kobj,
262 const struct attribute_group **groups)
263{
264 return internal_create_groups(kobj, 1, groups);
265}
266EXPORT_SYMBOL_GPL(sysfs_update_groups);
267
268/**
269 * sysfs_update_group - given a directory kobject, update an attribute group
270 * @kobj: The kobject to update the group on
271 * @grp: The attribute group to update
272 *
273 * This function updates an attribute group. Unlike
274 * sysfs_create_group(), it will explicitly not warn or error if any
275 * of the attribute files being created already exist. Furthermore,
276 * if the visibility of the files has changed through the is_visible()
277 * callback, it will update the permissions and add or remove the
278 * relevant files. Changing a group's name (subdirectory name under
279 * kobj's directory in sysfs) is not allowed.
280 *
281 * The primary use for this function is to call it after making a change
282 * that affects group visibility.
283 *
284 * Returns 0 on success or error code on failure.
285 */
286int sysfs_update_group(struct kobject *kobj,
287 const struct attribute_group *grp)
288{
289 return internal_create_group(kobj, 1, grp);
290}
291EXPORT_SYMBOL_GPL(sysfs_update_group);
292
293/**
294 * sysfs_remove_group: remove a group from a kobject
295 * @kobj: kobject to remove the group from
296 * @grp: group to remove
297 *
298 * This function removes a group of attributes from a kobject. The attributes
299 * previously have to have been created for this group, otherwise it will fail.
300 */
301void sysfs_remove_group(struct kobject *kobj,
302 const struct attribute_group *grp)
303{
304 struct kernfs_node *parent = kobj->sd;
305 struct kernfs_node *kn;
306
307 if (grp->name) {
308 kn = kernfs_find_and_get(parent, grp->name);
309 if (!kn) {
310 pr_debug("sysfs group '%s' not found for kobject '%s'\n",
311 grp->name, kobject_name(kobj));
312 return;
313 }
314 } else {
315 kn = parent;
316 kernfs_get(kn);
317 }
318
319 remove_files(kn, grp);
320 if (grp->name)
321 kernfs_remove(kn);
322
323 kernfs_put(kn);
324}
325EXPORT_SYMBOL_GPL(sysfs_remove_group);
326
327/**
328 * sysfs_remove_groups - remove a list of groups
329 *
330 * @kobj: The kobject for the groups to be removed from
331 * @groups: NULL terminated list of groups to be removed
332 *
333 * If groups is not NULL, remove the specified groups from the kobject.
334 */
335void sysfs_remove_groups(struct kobject *kobj,
336 const struct attribute_group **groups)
337{
338 int i;
339
340 if (!groups)
341 return;
342 for (i = 0; groups[i]; i++)
343 sysfs_remove_group(kobj, groups[i]);
344}
345EXPORT_SYMBOL_GPL(sysfs_remove_groups);
346
347/**
348 * sysfs_merge_group - merge files into a pre-existing named attribute group.
349 * @kobj: The kobject containing the group.
350 * @grp: The files to create and the attribute group they belong to.
351 *
352 * This function returns an error if the group doesn't exist, the .name field is
353 * NULL or any of the files already exist in that group, in which case none of
354 * the new files are created.
355 */
356int sysfs_merge_group(struct kobject *kobj,
357 const struct attribute_group *grp)
358{
359 struct kernfs_node *parent;
360 kuid_t uid;
361 kgid_t gid;
362 int error = 0;
363 struct attribute *const *attr;
364 int i;
365
366 parent = kernfs_find_and_get(kobj->sd, grp->name);
367 if (!parent)
368 return -ENOENT;
369
370 kobject_get_ownership(kobj, &uid, &gid);
371
372 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
373 error = sysfs_add_file_mode_ns(parent, *attr, (*attr)->mode,
374 uid, gid, NULL);
375 if (error) {
376 while (--i >= 0)
377 kernfs_remove_by_name(parent, (*--attr)->name);
378 }
379 kernfs_put(parent);
380
381 return error;
382}
383EXPORT_SYMBOL_GPL(sysfs_merge_group);
384
385/**
386 * sysfs_unmerge_group - remove files from a pre-existing named attribute group.
387 * @kobj: The kobject containing the group.
388 * @grp: The files to remove and the attribute group they belong to.
389 */
390void sysfs_unmerge_group(struct kobject *kobj,
391 const struct attribute_group *grp)
392{
393 struct kernfs_node *parent;
394 struct attribute *const *attr;
395
396 parent = kernfs_find_and_get(kobj->sd, grp->name);
397 if (parent) {
398 for (attr = grp->attrs; *attr; ++attr)
399 kernfs_remove_by_name(parent, (*attr)->name);
400 kernfs_put(parent);
401 }
402}
403EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
404
405/**
406 * sysfs_add_link_to_group - add a symlink to an attribute group.
407 * @kobj: The kobject containing the group.
408 * @group_name: The name of the group.
409 * @target: The target kobject of the symlink to create.
410 * @link_name: The name of the symlink to create.
411 */
412int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
413 struct kobject *target, const char *link_name)
414{
415 struct kernfs_node *parent;
416 int error = 0;
417
418 parent = kernfs_find_and_get(kobj->sd, group_name);
419 if (!parent)
420 return -ENOENT;
421
422 error = sysfs_create_link_sd(parent, target, link_name);
423 kernfs_put(parent);
424
425 return error;
426}
427EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
428
429/**
430 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
431 * @kobj: The kobject containing the group.
432 * @group_name: The name of the group.
433 * @link_name: The name of the symlink to remove.
434 */
435void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
436 const char *link_name)
437{
438 struct kernfs_node *parent;
439
440 parent = kernfs_find_and_get(kobj->sd, group_name);
441 if (parent) {
442 kernfs_remove_by_name(parent, link_name);
443 kernfs_put(parent);
444 }
445}
446EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
447
448/**
449 * compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
450 * to a group or an attribute
451 * @kobj: The kobject containing the group.
452 * @target_kobj: The target kobject.
453 * @target_name: The name of the target group or attribute.
454 * @symlink_name: The name of the symlink file (target_name will be
455 * considered if symlink_name is NULL).
456 */
457int compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
458 struct kobject *target_kobj,
459 const char *target_name,
460 const char *symlink_name)
461{
462 struct kernfs_node *target;
463 struct kernfs_node *entry;
464 struct kernfs_node *link;
465
466 /*
467 * We don't own @target_kobj and it may be removed at any time.
468 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
469 * for details.
470 */
471 spin_lock(&sysfs_symlink_target_lock);
472 target = target_kobj->sd;
473 if (target)
474 kernfs_get(target);
475 spin_unlock(&sysfs_symlink_target_lock);
476 if (!target)
477 return -ENOENT;
478
479 entry = kernfs_find_and_get(target, target_name);
480 if (!entry) {
481 kernfs_put(target);
482 return -ENOENT;
483 }
484
485 if (!symlink_name)
486 symlink_name = target_name;
487
488 link = kernfs_create_link(kobj->sd, symlink_name, entry);
489 if (PTR_ERR(link) == -EEXIST)
490 sysfs_warn_dup(kobj->sd, symlink_name);
491
492 kernfs_put(entry);
493 kernfs_put(target);
494 return PTR_ERR_OR_ZERO(link);
495}
496EXPORT_SYMBOL_GPL(compat_only_sysfs_link_entry_to_kobj);
497
498static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
499 const struct attribute_group *grp,
500 struct iattr *newattrs)
501{
502 struct kernfs_node *kn;
503 int error;
504
505 if (grp->attrs) {
506 struct attribute *const *attr;
507
508 for (attr = grp->attrs; *attr; attr++) {
509 kn = kernfs_find_and_get(grp_kn, (*attr)->name);
510 if (!kn)
511 return -ENOENT;
512
513 error = kernfs_setattr(kn, newattrs);
514 kernfs_put(kn);
515 if (error)
516 return error;
517 }
518 }
519
520 if (grp->bin_attrs) {
521 struct bin_attribute *const *bin_attr;
522
523 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
524 kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
525 if (!kn)
526 return -ENOENT;
527
528 error = kernfs_setattr(kn, newattrs);
529 kernfs_put(kn);
530 if (error)
531 return error;
532 }
533 }
534
535 return 0;
536}
537
538/**
539 * sysfs_group_change_owner - change owner of an attribute group.
540 * @kobj: The kobject containing the group.
541 * @grp: The attribute group.
542 * @kuid: new owner's kuid
543 * @kgid: new owner's kgid
544 *
545 * Returns 0 on success or error code on failure.
546 */
547int sysfs_group_change_owner(struct kobject *kobj,
548 const struct attribute_group *grp, kuid_t kuid,
549 kgid_t kgid)
550{
551 struct kernfs_node *grp_kn;
552 int error;
553 struct iattr newattrs = {
554 .ia_valid = ATTR_UID | ATTR_GID,
555 .ia_uid = kuid,
556 .ia_gid = kgid,
557 };
558
559 if (!kobj->state_in_sysfs)
560 return -EINVAL;
561
562 if (grp->name) {
563 grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
564 } else {
565 kernfs_get(kobj->sd);
566 grp_kn = kobj->sd;
567 }
568 if (!grp_kn)
569 return -ENOENT;
570
571 error = kernfs_setattr(grp_kn, &newattrs);
572 if (!error)
573 error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
574
575 kernfs_put(grp_kn);
576
577 return error;
578}
579EXPORT_SYMBOL_GPL(sysfs_group_change_owner);
580
581/**
582 * sysfs_groups_change_owner - change owner of a set of attribute groups.
583 * @kobj: The kobject containing the groups.
584 * @groups: The attribute groups.
585 * @kuid: new owner's kuid
586 * @kgid: new owner's kgid
587 *
588 * Returns 0 on success or error code on failure.
589 */
590int sysfs_groups_change_owner(struct kobject *kobj,
591 const struct attribute_group **groups,
592 kuid_t kuid, kgid_t kgid)
593{
594 int error = 0, i;
595
596 if (!kobj->state_in_sysfs)
597 return -EINVAL;
598
599 if (!groups)
600 return 0;
601
602 for (i = 0; groups[i]; i++) {
603 error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
604 if (error)
605 break;
606 }
607
608 return error;
609}
610EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);
1/*
2 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
3 *
4 * Copyright (c) 2003 Patrick Mochel
5 * Copyright (c) 2003 Open Source Development Lab
6 * Copyright (c) 2013 Greg Kroah-Hartman
7 * Copyright (c) 2013 The Linux Foundation
8 *
9 * This file is released undert the GPL v2.
10 *
11 */
12
13#include <linux/kobject.h>
14#include <linux/module.h>
15#include <linux/dcache.h>
16#include <linux/namei.h>
17#include <linux/err.h>
18#include "sysfs.h"
19
20
21static void remove_files(struct kernfs_node *parent,
22 const struct attribute_group *grp)
23{
24 struct attribute *const *attr;
25 struct bin_attribute *const *bin_attr;
26
27 if (grp->attrs)
28 for (attr = grp->attrs; *attr; attr++)
29 kernfs_remove_by_name(parent, (*attr)->name);
30 if (grp->bin_attrs)
31 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
32 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
33}
34
35static int create_files(struct kernfs_node *parent, struct kobject *kobj,
36 const struct attribute_group *grp, int update)
37{
38 struct attribute *const *attr;
39 struct bin_attribute *const *bin_attr;
40 int error = 0, i;
41
42 if (grp->attrs) {
43 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
44 umode_t mode = (*attr)->mode;
45
46 /*
47 * In update mode, we're changing the permissions or
48 * visibility. Do this by first removing then
49 * re-adding (if required) the file.
50 */
51 if (update)
52 kernfs_remove_by_name(parent, (*attr)->name);
53 if (grp->is_visible) {
54 mode = grp->is_visible(kobj, *attr, i);
55 if (!mode)
56 continue;
57 }
58
59 WARN(mode & ~(SYSFS_PREALLOC | 0664),
60 "Attribute %s: Invalid permissions 0%o\n",
61 (*attr)->name, mode);
62
63 mode &= SYSFS_PREALLOC | 0664;
64 error = sysfs_add_file_mode_ns(parent, *attr, false,
65 mode, NULL);
66 if (unlikely(error))
67 break;
68 }
69 if (error) {
70 remove_files(parent, grp);
71 goto exit;
72 }
73 }
74
75 if (grp->bin_attrs) {
76 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
77 umode_t mode = (*bin_attr)->attr.mode;
78
79 if (update)
80 kernfs_remove_by_name(parent,
81 (*bin_attr)->attr.name);
82 if (grp->is_bin_visible) {
83 mode = grp->is_bin_visible(kobj, *bin_attr, i);
84 if (!mode)
85 continue;
86 }
87
88 WARN(mode & ~(SYSFS_PREALLOC | 0664),
89 "Attribute %s: Invalid permissions 0%o\n",
90 (*bin_attr)->attr.name, mode);
91
92 mode &= SYSFS_PREALLOC | 0664;
93 error = sysfs_add_file_mode_ns(parent,
94 &(*bin_attr)->attr, true,
95 mode, NULL);
96 if (error)
97 break;
98 }
99 if (error)
100 remove_files(parent, grp);
101 }
102exit:
103 return error;
104}
105
106
107static int internal_create_group(struct kobject *kobj, int update,
108 const struct attribute_group *grp)
109{
110 struct kernfs_node *kn;
111 int error;
112
113 BUG_ON(!kobj || (!update && !kobj->sd));
114
115 /* Updates may happen before the object has been instantiated */
116 if (unlikely(update && !kobj->sd))
117 return -EINVAL;
118 if (!grp->attrs && !grp->bin_attrs) {
119 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
120 kobj->name, grp->name ?: "");
121 return -EINVAL;
122 }
123 if (grp->name) {
124 kn = kernfs_create_dir(kobj->sd, grp->name,
125 S_IRWXU | S_IRUGO | S_IXUGO, kobj);
126 if (IS_ERR(kn)) {
127 if (PTR_ERR(kn) == -EEXIST)
128 sysfs_warn_dup(kobj->sd, grp->name);
129 return PTR_ERR(kn);
130 }
131 } else
132 kn = kobj->sd;
133 kernfs_get(kn);
134 error = create_files(kn, kobj, grp, update);
135 if (error) {
136 if (grp->name)
137 kernfs_remove(kn);
138 }
139 kernfs_put(kn);
140 return error;
141}
142
143/**
144 * sysfs_create_group - given a directory kobject, create an attribute group
145 * @kobj: The kobject to create the group on
146 * @grp: The attribute group to create
147 *
148 * This function creates a group for the first time. It will explicitly
149 * warn and error if any of the attribute files being created already exist.
150 *
151 * Returns 0 on success or error code on failure.
152 */
153int sysfs_create_group(struct kobject *kobj,
154 const struct attribute_group *grp)
155{
156 return internal_create_group(kobj, 0, grp);
157}
158EXPORT_SYMBOL_GPL(sysfs_create_group);
159
160/**
161 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
162 * @kobj: The kobject to create the group on
163 * @groups: The attribute groups to create, NULL terminated
164 *
165 * This function creates a bunch of attribute groups. If an error occurs when
166 * creating a group, all previously created groups will be removed, unwinding
167 * everything back to the original state when this function was called.
168 * It will explicitly warn and error if any of the attribute files being
169 * created already exist.
170 *
171 * Returns 0 on success or error code from sysfs_create_group on failure.
172 */
173int sysfs_create_groups(struct kobject *kobj,
174 const struct attribute_group **groups)
175{
176 int error = 0;
177 int i;
178
179 if (!groups)
180 return 0;
181
182 for (i = 0; groups[i]; i++) {
183 error = sysfs_create_group(kobj, groups[i]);
184 if (error) {
185 while (--i >= 0)
186 sysfs_remove_group(kobj, groups[i]);
187 break;
188 }
189 }
190 return error;
191}
192EXPORT_SYMBOL_GPL(sysfs_create_groups);
193
194/**
195 * sysfs_update_group - given a directory kobject, update an attribute group
196 * @kobj: The kobject to update the group on
197 * @grp: The attribute group to update
198 *
199 * This function updates an attribute group. Unlike
200 * sysfs_create_group(), it will explicitly not warn or error if any
201 * of the attribute files being created already exist. Furthermore,
202 * if the visibility of the files has changed through the is_visible()
203 * callback, it will update the permissions and add or remove the
204 * relevant files.
205 *
206 * The primary use for this function is to call it after making a change
207 * that affects group visibility.
208 *
209 * Returns 0 on success or error code on failure.
210 */
211int sysfs_update_group(struct kobject *kobj,
212 const struct attribute_group *grp)
213{
214 return internal_create_group(kobj, 1, grp);
215}
216EXPORT_SYMBOL_GPL(sysfs_update_group);
217
218/**
219 * sysfs_remove_group: remove a group from a kobject
220 * @kobj: kobject to remove the group from
221 * @grp: group to remove
222 *
223 * This function removes a group of attributes from a kobject. The attributes
224 * previously have to have been created for this group, otherwise it will fail.
225 */
226void sysfs_remove_group(struct kobject *kobj,
227 const struct attribute_group *grp)
228{
229 struct kernfs_node *parent = kobj->sd;
230 struct kernfs_node *kn;
231
232 if (grp->name) {
233 kn = kernfs_find_and_get(parent, grp->name);
234 if (!kn) {
235 WARN(!kn, KERN_WARNING
236 "sysfs group %p not found for kobject '%s'\n",
237 grp, kobject_name(kobj));
238 return;
239 }
240 } else {
241 kn = parent;
242 kernfs_get(kn);
243 }
244
245 remove_files(kn, grp);
246 if (grp->name)
247 kernfs_remove(kn);
248
249 kernfs_put(kn);
250}
251EXPORT_SYMBOL_GPL(sysfs_remove_group);
252
253/**
254 * sysfs_remove_groups - remove a list of groups
255 *
256 * @kobj: The kobject for the groups to be removed from
257 * @groups: NULL terminated list of groups to be removed
258 *
259 * If groups is not NULL, remove the specified groups from the kobject.
260 */
261void sysfs_remove_groups(struct kobject *kobj,
262 const struct attribute_group **groups)
263{
264 int i;
265
266 if (!groups)
267 return;
268 for (i = 0; groups[i]; i++)
269 sysfs_remove_group(kobj, groups[i]);
270}
271EXPORT_SYMBOL_GPL(sysfs_remove_groups);
272
273/**
274 * sysfs_merge_group - merge files into a pre-existing attribute group.
275 * @kobj: The kobject containing the group.
276 * @grp: The files to create and the attribute group they belong to.
277 *
278 * This function returns an error if the group doesn't exist or any of the
279 * files already exist in that group, in which case none of the new files
280 * are created.
281 */
282int sysfs_merge_group(struct kobject *kobj,
283 const struct attribute_group *grp)
284{
285 struct kernfs_node *parent;
286 int error = 0;
287 struct attribute *const *attr;
288 int i;
289
290 parent = kernfs_find_and_get(kobj->sd, grp->name);
291 if (!parent)
292 return -ENOENT;
293
294 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
295 error = sysfs_add_file(parent, *attr, false);
296 if (error) {
297 while (--i >= 0)
298 kernfs_remove_by_name(parent, (*--attr)->name);
299 }
300 kernfs_put(parent);
301
302 return error;
303}
304EXPORT_SYMBOL_GPL(sysfs_merge_group);
305
306/**
307 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
308 * @kobj: The kobject containing the group.
309 * @grp: The files to remove and the attribute group they belong to.
310 */
311void sysfs_unmerge_group(struct kobject *kobj,
312 const struct attribute_group *grp)
313{
314 struct kernfs_node *parent;
315 struct attribute *const *attr;
316
317 parent = kernfs_find_and_get(kobj->sd, grp->name);
318 if (parent) {
319 for (attr = grp->attrs; *attr; ++attr)
320 kernfs_remove_by_name(parent, (*attr)->name);
321 kernfs_put(parent);
322 }
323}
324EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
325
326/**
327 * sysfs_add_link_to_group - add a symlink to an attribute group.
328 * @kobj: The kobject containing the group.
329 * @group_name: The name of the group.
330 * @target: The target kobject of the symlink to create.
331 * @link_name: The name of the symlink to create.
332 */
333int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
334 struct kobject *target, const char *link_name)
335{
336 struct kernfs_node *parent;
337 int error = 0;
338
339 parent = kernfs_find_and_get(kobj->sd, group_name);
340 if (!parent)
341 return -ENOENT;
342
343 error = sysfs_create_link_sd(parent, target, link_name);
344 kernfs_put(parent);
345
346 return error;
347}
348EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
349
350/**
351 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
352 * @kobj: The kobject containing the group.
353 * @group_name: The name of the group.
354 * @link_name: The name of the symlink to remove.
355 */
356void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
357 const char *link_name)
358{
359 struct kernfs_node *parent;
360
361 parent = kernfs_find_and_get(kobj->sd, group_name);
362 if (parent) {
363 kernfs_remove_by_name(parent, link_name);
364 kernfs_put(parent);
365 }
366}
367EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
368
369/**
370 * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
371 * to a group or an attribute
372 * @kobj: The kobject containing the group.
373 * @target_kobj: The target kobject.
374 * @target_name: The name of the target group or attribute.
375 */
376int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
377 struct kobject *target_kobj,
378 const char *target_name)
379{
380 struct kernfs_node *target;
381 struct kernfs_node *entry;
382 struct kernfs_node *link;
383
384 /*
385 * We don't own @target_kobj and it may be removed at any time.
386 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
387 * for details.
388 */
389 spin_lock(&sysfs_symlink_target_lock);
390 target = target_kobj->sd;
391 if (target)
392 kernfs_get(target);
393 spin_unlock(&sysfs_symlink_target_lock);
394 if (!target)
395 return -ENOENT;
396
397 entry = kernfs_find_and_get(target_kobj->sd, target_name);
398 if (!entry) {
399 kernfs_put(target);
400 return -ENOENT;
401 }
402
403 link = kernfs_create_link(kobj->sd, target_name, entry);
404 if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
405 sysfs_warn_dup(kobj->sd, target_name);
406
407 kernfs_put(entry);
408 kernfs_put(target);
409 return IS_ERR(link) ? PTR_ERR(link) : 0;
410}
411EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);