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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 int create_files(struct kernfs_node *parent, struct kobject *kobj,
35 kuid_t uid, kgid_t gid,
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, uid, gid, 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,
96 uid, gid, NULL);
97 if (error)
98 break;
99 }
100 if (error)
101 remove_files(parent, grp);
102 }
103exit:
104 return error;
105}
106
107
108static int internal_create_group(struct kobject *kobj, int update,
109 const struct attribute_group *grp)
110{
111 struct kernfs_node *kn;
112 kuid_t uid;
113 kgid_t gid;
114 int error;
115
116 if (WARN_ON(!kobj || (!update && !kobj->sd)))
117 return -EINVAL;
118
119 /* Updates may happen before the object has been instantiated */
120 if (unlikely(update && !kobj->sd))
121 return -EINVAL;
122 if (!grp->attrs && !grp->bin_attrs) {
123 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
124 kobj->name, grp->name ?: "");
125 return -EINVAL;
126 }
127 kobject_get_ownership(kobj, &uid, &gid);
128 if (grp->name) {
129 if (update) {
130 kn = kernfs_find_and_get(kobj->sd, grp->name);
131 if (!kn) {
132 pr_warn("Can't update unknown attr grp name: %s/%s\n",
133 kobj->name, grp->name);
134 return -EINVAL;
135 }
136 } else {
137 kn = kernfs_create_dir_ns(kobj->sd, grp->name,
138 S_IRWXU | S_IRUGO | S_IXUGO,
139 uid, gid, kobj, NULL);
140 if (IS_ERR(kn)) {
141 if (PTR_ERR(kn) == -EEXIST)
142 sysfs_warn_dup(kobj->sd, grp->name);
143 return PTR_ERR(kn);
144 }
145 }
146 } else
147 kn = kobj->sd;
148 kernfs_get(kn);
149 error = create_files(kn, kobj, uid, gid, grp, update);
150 if (error) {
151 if (grp->name)
152 kernfs_remove(kn);
153 }
154 kernfs_put(kn);
155
156 if (grp->name && update)
157 kernfs_put(kn);
158
159 return error;
160}
161
162/**
163 * sysfs_create_group - given a directory kobject, create an attribute group
164 * @kobj: The kobject to create the group on
165 * @grp: The attribute group to create
166 *
167 * This function creates a group for the first time. It will explicitly
168 * warn and error if any of the attribute files being created already exist.
169 *
170 * Returns 0 on success or error code on failure.
171 */
172int sysfs_create_group(struct kobject *kobj,
173 const struct attribute_group *grp)
174{
175 return internal_create_group(kobj, 0, grp);
176}
177EXPORT_SYMBOL_GPL(sysfs_create_group);
178
179static int internal_create_groups(struct kobject *kobj, int update,
180 const struct attribute_group **groups)
181{
182 int error = 0;
183 int i;
184
185 if (!groups)
186 return 0;
187
188 for (i = 0; groups[i]; i++) {
189 error = internal_create_group(kobj, update, groups[i]);
190 if (error) {
191 while (--i >= 0)
192 sysfs_remove_group(kobj, groups[i]);
193 break;
194 }
195 }
196 return error;
197}
198
199/**
200 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
201 * @kobj: The kobject to create the group on
202 * @groups: The attribute groups to create, NULL terminated
203 *
204 * This function creates a bunch of attribute groups. If an error occurs when
205 * creating a group, all previously created groups will be removed, unwinding
206 * everything back to the original state when this function was called.
207 * It will explicitly warn and error if any of the attribute files being
208 * created already exist.
209 *
210 * Returns 0 on success or error code from sysfs_create_group on failure.
211 */
212int sysfs_create_groups(struct kobject *kobj,
213 const struct attribute_group **groups)
214{
215 return internal_create_groups(kobj, 0, groups);
216}
217EXPORT_SYMBOL_GPL(sysfs_create_groups);
218
219/**
220 * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
221 * @kobj: The kobject to update the group on
222 * @groups: The attribute groups to update, NULL terminated
223 *
224 * This function update a bunch of attribute groups. If an error occurs when
225 * updating a group, all previously updated groups will be removed together
226 * with already existing (not updated) attributes.
227 *
228 * Returns 0 on success or error code from sysfs_update_group on failure.
229 */
230int sysfs_update_groups(struct kobject *kobj,
231 const struct attribute_group **groups)
232{
233 return internal_create_groups(kobj, 1, groups);
234}
235EXPORT_SYMBOL_GPL(sysfs_update_groups);
236
237/**
238 * sysfs_update_group - given a directory kobject, update an attribute group
239 * @kobj: The kobject to update the group on
240 * @grp: The attribute group to update
241 *
242 * This function updates an attribute group. Unlike
243 * sysfs_create_group(), it will explicitly not warn or error if any
244 * of the attribute files being created already exist. Furthermore,
245 * if the visibility of the files has changed through the is_visible()
246 * callback, it will update the permissions and add or remove the
247 * relevant files. Changing a group's name (subdirectory name under
248 * kobj's directory in sysfs) is not allowed.
249 *
250 * The primary use for this function is to call it after making a change
251 * that affects group visibility.
252 *
253 * Returns 0 on success or error code on failure.
254 */
255int sysfs_update_group(struct kobject *kobj,
256 const struct attribute_group *grp)
257{
258 return internal_create_group(kobj, 1, grp);
259}
260EXPORT_SYMBOL_GPL(sysfs_update_group);
261
262/**
263 * sysfs_remove_group: remove a group from a kobject
264 * @kobj: kobject to remove the group from
265 * @grp: group to remove
266 *
267 * This function removes a group of attributes from a kobject. The attributes
268 * previously have to have been created for this group, otherwise it will fail.
269 */
270void sysfs_remove_group(struct kobject *kobj,
271 const struct attribute_group *grp)
272{
273 struct kernfs_node *parent = kobj->sd;
274 struct kernfs_node *kn;
275
276 if (grp->name) {
277 kn = kernfs_find_and_get(parent, grp->name);
278 if (!kn) {
279 WARN(!kn, KERN_WARNING
280 "sysfs group '%s' not found for kobject '%s'\n",
281 grp->name, kobject_name(kobj));
282 return;
283 }
284 } else {
285 kn = parent;
286 kernfs_get(kn);
287 }
288
289 remove_files(kn, grp);
290 if (grp->name)
291 kernfs_remove(kn);
292
293 kernfs_put(kn);
294}
295EXPORT_SYMBOL_GPL(sysfs_remove_group);
296
297/**
298 * sysfs_remove_groups - remove a list of groups
299 *
300 * @kobj: The kobject for the groups to be removed from
301 * @groups: NULL terminated list of groups to be removed
302 *
303 * If groups is not NULL, remove the specified groups from the kobject.
304 */
305void sysfs_remove_groups(struct kobject *kobj,
306 const struct attribute_group **groups)
307{
308 int i;
309
310 if (!groups)
311 return;
312 for (i = 0; groups[i]; i++)
313 sysfs_remove_group(kobj, groups[i]);
314}
315EXPORT_SYMBOL_GPL(sysfs_remove_groups);
316
317/**
318 * sysfs_merge_group - merge files into a pre-existing attribute group.
319 * @kobj: The kobject containing the group.
320 * @grp: The files to create and the attribute group they belong to.
321 *
322 * This function returns an error if the group doesn't exist or any of the
323 * files already exist in that group, in which case none of the new files
324 * are created.
325 */
326int sysfs_merge_group(struct kobject *kobj,
327 const struct attribute_group *grp)
328{
329 struct kernfs_node *parent;
330 kuid_t uid;
331 kgid_t gid;
332 int error = 0;
333 struct attribute *const *attr;
334 int i;
335
336 parent = kernfs_find_and_get(kobj->sd, grp->name);
337 if (!parent)
338 return -ENOENT;
339
340 kobject_get_ownership(kobj, &uid, &gid);
341
342 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
343 error = sysfs_add_file_mode_ns(parent, *attr, false,
344 (*attr)->mode, uid, gid, NULL);
345 if (error) {
346 while (--i >= 0)
347 kernfs_remove_by_name(parent, (*--attr)->name);
348 }
349 kernfs_put(parent);
350
351 return error;
352}
353EXPORT_SYMBOL_GPL(sysfs_merge_group);
354
355/**
356 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
357 * @kobj: The kobject containing the group.
358 * @grp: The files to remove and the attribute group they belong to.
359 */
360void sysfs_unmerge_group(struct kobject *kobj,
361 const struct attribute_group *grp)
362{
363 struct kernfs_node *parent;
364 struct attribute *const *attr;
365
366 parent = kernfs_find_and_get(kobj->sd, grp->name);
367 if (parent) {
368 for (attr = grp->attrs; *attr; ++attr)
369 kernfs_remove_by_name(parent, (*attr)->name);
370 kernfs_put(parent);
371 }
372}
373EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
374
375/**
376 * sysfs_add_link_to_group - add a symlink to an attribute group.
377 * @kobj: The kobject containing the group.
378 * @group_name: The name of the group.
379 * @target: The target kobject of the symlink to create.
380 * @link_name: The name of the symlink to create.
381 */
382int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
383 struct kobject *target, const char *link_name)
384{
385 struct kernfs_node *parent;
386 int error = 0;
387
388 parent = kernfs_find_and_get(kobj->sd, group_name);
389 if (!parent)
390 return -ENOENT;
391
392 error = sysfs_create_link_sd(parent, target, link_name);
393 kernfs_put(parent);
394
395 return error;
396}
397EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
398
399/**
400 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
401 * @kobj: The kobject containing the group.
402 * @group_name: The name of the group.
403 * @link_name: The name of the symlink to remove.
404 */
405void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
406 const char *link_name)
407{
408 struct kernfs_node *parent;
409
410 parent = kernfs_find_and_get(kobj->sd, group_name);
411 if (parent) {
412 kernfs_remove_by_name(parent, link_name);
413 kernfs_put(parent);
414 }
415}
416EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
417
418/**
419 * compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
420 * to a group or an attribute
421 * @kobj: The kobject containing the group.
422 * @target_kobj: The target kobject.
423 * @target_name: The name of the target group or attribute.
424 * @symlink_name: The name of the symlink file (target_name will be
425 * considered if symlink_name is NULL).
426 */
427int compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
428 struct kobject *target_kobj,
429 const char *target_name,
430 const char *symlink_name)
431{
432 struct kernfs_node *target;
433 struct kernfs_node *entry;
434 struct kernfs_node *link;
435
436 /*
437 * We don't own @target_kobj and it may be removed at any time.
438 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
439 * for details.
440 */
441 spin_lock(&sysfs_symlink_target_lock);
442 target = target_kobj->sd;
443 if (target)
444 kernfs_get(target);
445 spin_unlock(&sysfs_symlink_target_lock);
446 if (!target)
447 return -ENOENT;
448
449 entry = kernfs_find_and_get(target_kobj->sd, target_name);
450 if (!entry) {
451 kernfs_put(target);
452 return -ENOENT;
453 }
454
455 if (!symlink_name)
456 symlink_name = target_name;
457
458 link = kernfs_create_link(kobj->sd, symlink_name, entry);
459 if (PTR_ERR(link) == -EEXIST)
460 sysfs_warn_dup(kobj->sd, symlink_name);
461
462 kernfs_put(entry);
463 kernfs_put(target);
464 return PTR_ERR_OR_ZERO(link);
465}
466EXPORT_SYMBOL_GPL(compat_only_sysfs_link_entry_to_kobj);
467
468static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
469 const struct attribute_group *grp,
470 struct iattr *newattrs)
471{
472 struct kernfs_node *kn;
473 int error;
474
475 if (grp->attrs) {
476 struct attribute *const *attr;
477
478 for (attr = grp->attrs; *attr; attr++) {
479 kn = kernfs_find_and_get(grp_kn, (*attr)->name);
480 if (!kn)
481 return -ENOENT;
482
483 error = kernfs_setattr(kn, newattrs);
484 kernfs_put(kn);
485 if (error)
486 return error;
487 }
488 }
489
490 if (grp->bin_attrs) {
491 struct bin_attribute *const *bin_attr;
492
493 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
494 kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
495 if (!kn)
496 return -ENOENT;
497
498 error = kernfs_setattr(kn, newattrs);
499 kernfs_put(kn);
500 if (error)
501 return error;
502 }
503 }
504
505 return 0;
506}
507
508/**
509 * sysfs_group_change_owner - change owner of an attribute group.
510 * @kobj: The kobject containing the group.
511 * @grp: The attribute group.
512 * @kuid: new owner's kuid
513 * @kgid: new owner's kgid
514 *
515 * Returns 0 on success or error code on failure.
516 */
517int sysfs_group_change_owner(struct kobject *kobj,
518 const struct attribute_group *grp, kuid_t kuid,
519 kgid_t kgid)
520{
521 struct kernfs_node *grp_kn;
522 int error;
523 struct iattr newattrs = {
524 .ia_valid = ATTR_UID | ATTR_GID,
525 .ia_uid = kuid,
526 .ia_gid = kgid,
527 };
528
529 if (!kobj->state_in_sysfs)
530 return -EINVAL;
531
532 if (grp->name) {
533 grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
534 } else {
535 kernfs_get(kobj->sd);
536 grp_kn = kobj->sd;
537 }
538 if (!grp_kn)
539 return -ENOENT;
540
541 error = kernfs_setattr(grp_kn, &newattrs);
542 if (!error)
543 error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
544
545 kernfs_put(grp_kn);
546
547 return error;
548}
549EXPORT_SYMBOL_GPL(sysfs_group_change_owner);
550
551/**
552 * sysfs_groups_change_owner - change owner of a set of attribute groups.
553 * @kobj: The kobject containing the groups.
554 * @groups: The attribute groups.
555 * @kuid: new owner's kuid
556 * @kgid: new owner's kgid
557 *
558 * Returns 0 on success or error code on failure.
559 */
560int sysfs_groups_change_owner(struct kobject *kobj,
561 const struct attribute_group **groups,
562 kuid_t kuid, kgid_t kgid)
563{
564 int error = 0, i;
565
566 if (!kobj->state_in_sysfs)
567 return -EINVAL;
568
569 if (!groups)
570 return 0;
571
572 for (i = 0; groups[i]; i++) {
573 error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
574 if (error)
575 break;
576 }
577
578 return error;
579}
580EXPORT_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);