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