Loading...
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 size_t size = (*bin_attr)->size;
91
92 if (update)
93 kernfs_remove_by_name(parent,
94 (*bin_attr)->attr.name);
95 if (grp->is_bin_visible) {
96 mode = grp->is_bin_visible(kobj, *bin_attr, i);
97 mode &= ~SYSFS_GROUP_INVISIBLE;
98 if (!mode)
99 continue;
100 }
101 if (grp->bin_size)
102 size = grp->bin_size(kobj, *bin_attr, i);
103
104 WARN(mode & ~(SYSFS_PREALLOC | 0664),
105 "Attribute %s: Invalid permissions 0%o\n",
106 (*bin_attr)->attr.name, mode);
107
108 mode &= SYSFS_PREALLOC | 0664;
109 error = sysfs_add_bin_file_mode_ns(parent, *bin_attr,
110 mode, size, uid, gid,
111 NULL);
112 if (error)
113 break;
114 }
115 if (error)
116 remove_files(parent, grp);
117 }
118exit:
119 return error;
120}
121
122
123static int internal_create_group(struct kobject *kobj, int update,
124 const struct attribute_group *grp)
125{
126 struct kernfs_node *kn;
127 kuid_t uid;
128 kgid_t gid;
129 int error;
130
131 if (WARN_ON(!kobj || (!update && !kobj->sd)))
132 return -EINVAL;
133
134 /* Updates may happen before the object has been instantiated */
135 if (unlikely(update && !kobj->sd))
136 return -EINVAL;
137
138 if (!grp->attrs && !grp->bin_attrs) {
139 pr_debug("sysfs: (bin_)attrs not set by subsystem for group: %s/%s, skipping\n",
140 kobj->name, grp->name ?: "");
141 return 0;
142 }
143
144 kobject_get_ownership(kobj, &uid, &gid);
145 if (grp->name) {
146 umode_t mode = __first_visible(grp, kobj);
147
148 if (mode & SYSFS_GROUP_INVISIBLE)
149 mode = 0;
150 else
151 mode = S_IRWXU | S_IRUGO | S_IXUGO;
152
153 if (update) {
154 kn = kernfs_find_and_get(kobj->sd, grp->name);
155 if (!kn) {
156 pr_debug("attr grp %s/%s not created yet\n",
157 kobj->name, grp->name);
158 /* may have been invisible prior to this update */
159 update = 0;
160 } else if (!mode) {
161 sysfs_remove_group(kobj, grp);
162 kernfs_put(kn);
163 return 0;
164 }
165 }
166
167 if (!update) {
168 if (!mode)
169 return 0;
170 kn = kernfs_create_dir_ns(kobj->sd, grp->name, mode,
171 uid, gid, kobj, NULL);
172 if (IS_ERR(kn)) {
173 if (PTR_ERR(kn) == -EEXIST)
174 sysfs_warn_dup(kobj->sd, grp->name);
175 return PTR_ERR(kn);
176 }
177 }
178 } else {
179 kn = kobj->sd;
180 }
181
182 kernfs_get(kn);
183 error = create_files(kn, kobj, uid, gid, grp, update);
184 if (error) {
185 if (grp->name)
186 kernfs_remove(kn);
187 }
188 kernfs_put(kn);
189
190 if (grp->name && update)
191 kernfs_put(kn);
192
193 return error;
194}
195
196/**
197 * sysfs_create_group - given a directory kobject, create an attribute group
198 * @kobj: The kobject to create the group on
199 * @grp: The attribute group to create
200 *
201 * This function creates a group for the first time. It will explicitly
202 * warn and error if any of the attribute files being created already exist.
203 *
204 * Returns 0 on success or error code on failure.
205 */
206int sysfs_create_group(struct kobject *kobj,
207 const struct attribute_group *grp)
208{
209 return internal_create_group(kobj, 0, grp);
210}
211EXPORT_SYMBOL_GPL(sysfs_create_group);
212
213static int internal_create_groups(struct kobject *kobj, int update,
214 const struct attribute_group **groups)
215{
216 int error = 0;
217 int i;
218
219 if (!groups)
220 return 0;
221
222 for (i = 0; groups[i]; i++) {
223 error = internal_create_group(kobj, update, groups[i]);
224 if (error) {
225 while (--i >= 0)
226 sysfs_remove_group(kobj, groups[i]);
227 break;
228 }
229 }
230 return error;
231}
232
233/**
234 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
235 * @kobj: The kobject to create the group on
236 * @groups: The attribute groups to create, NULL terminated
237 *
238 * This function creates a bunch of attribute groups. If an error occurs when
239 * creating a group, all previously created groups will be removed, unwinding
240 * everything back to the original state when this function was called.
241 * It will explicitly warn and error if any of the attribute files being
242 * created already exist.
243 *
244 * Returns 0 on success or error code from sysfs_create_group on failure.
245 */
246int sysfs_create_groups(struct kobject *kobj,
247 const struct attribute_group **groups)
248{
249 return internal_create_groups(kobj, 0, groups);
250}
251EXPORT_SYMBOL_GPL(sysfs_create_groups);
252
253/**
254 * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
255 * @kobj: The kobject to update the group on
256 * @groups: The attribute groups to update, NULL terminated
257 *
258 * This function update a bunch of attribute groups. If an error occurs when
259 * updating a group, all previously updated groups will be removed together
260 * with already existing (not updated) attributes.
261 *
262 * Returns 0 on success or error code from sysfs_update_group on failure.
263 */
264int sysfs_update_groups(struct kobject *kobj,
265 const struct attribute_group **groups)
266{
267 return internal_create_groups(kobj, 1, groups);
268}
269EXPORT_SYMBOL_GPL(sysfs_update_groups);
270
271/**
272 * sysfs_update_group - given a directory kobject, update an attribute group
273 * @kobj: The kobject to update the group on
274 * @grp: The attribute group to update
275 *
276 * This function updates an attribute group. Unlike
277 * sysfs_create_group(), it will explicitly not warn or error if any
278 * of the attribute files being created already exist. Furthermore,
279 * if the visibility of the files has changed through the is_visible()
280 * callback, it will update the permissions and add or remove the
281 * relevant files. Changing a group's name (subdirectory name under
282 * kobj's directory in sysfs) is not allowed.
283 *
284 * The primary use for this function is to call it after making a change
285 * that affects group visibility.
286 *
287 * Returns 0 on success or error code on failure.
288 */
289int sysfs_update_group(struct kobject *kobj,
290 const struct attribute_group *grp)
291{
292 return internal_create_group(kobj, 1, grp);
293}
294EXPORT_SYMBOL_GPL(sysfs_update_group);
295
296/**
297 * sysfs_remove_group: remove a group from a kobject
298 * @kobj: kobject to remove the group from
299 * @grp: group to remove
300 *
301 * This function removes a group of attributes from a kobject. The attributes
302 * previously have to have been created for this group, otherwise it will fail.
303 */
304void sysfs_remove_group(struct kobject *kobj,
305 const struct attribute_group *grp)
306{
307 struct kernfs_node *parent = kobj->sd;
308 struct kernfs_node *kn;
309
310 if (grp->name) {
311 kn = kernfs_find_and_get(parent, grp->name);
312 if (!kn) {
313 pr_debug("sysfs group '%s' not found for kobject '%s'\n",
314 grp->name, kobject_name(kobj));
315 return;
316 }
317 } else {
318 kn = parent;
319 kernfs_get(kn);
320 }
321
322 remove_files(kn, grp);
323 if (grp->name)
324 kernfs_remove(kn);
325
326 kernfs_put(kn);
327}
328EXPORT_SYMBOL_GPL(sysfs_remove_group);
329
330/**
331 * sysfs_remove_groups - remove a list of groups
332 *
333 * @kobj: The kobject for the groups to be removed from
334 * @groups: NULL terminated list of groups to be removed
335 *
336 * If groups is not NULL, remove the specified groups from the kobject.
337 */
338void sysfs_remove_groups(struct kobject *kobj,
339 const struct attribute_group **groups)
340{
341 int i;
342
343 if (!groups)
344 return;
345 for (i = 0; groups[i]; i++)
346 sysfs_remove_group(kobj, groups[i]);
347}
348EXPORT_SYMBOL_GPL(sysfs_remove_groups);
349
350/**
351 * sysfs_merge_group - merge files into a pre-existing named attribute group.
352 * @kobj: The kobject containing the group.
353 * @grp: The files to create and the attribute group they belong to.
354 *
355 * This function returns an error if the group doesn't exist, the .name field is
356 * NULL or any of the files already exist in that group, in which case none of
357 * the new files are created.
358 */
359int sysfs_merge_group(struct kobject *kobj,
360 const struct attribute_group *grp)
361{
362 struct kernfs_node *parent;
363 kuid_t uid;
364 kgid_t gid;
365 int error = 0;
366 struct attribute *const *attr;
367 int i;
368
369 parent = kernfs_find_and_get(kobj->sd, grp->name);
370 if (!parent)
371 return -ENOENT;
372
373 kobject_get_ownership(kobj, &uid, &gid);
374
375 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
376 error = sysfs_add_file_mode_ns(parent, *attr, (*attr)->mode,
377 uid, gid, NULL);
378 if (error) {
379 while (--i >= 0)
380 kernfs_remove_by_name(parent, (*--attr)->name);
381 }
382 kernfs_put(parent);
383
384 return error;
385}
386EXPORT_SYMBOL_GPL(sysfs_merge_group);
387
388/**
389 * sysfs_unmerge_group - remove files from a pre-existing named attribute group.
390 * @kobj: The kobject containing the group.
391 * @grp: The files to remove and the attribute group they belong to.
392 */
393void sysfs_unmerge_group(struct kobject *kobj,
394 const struct attribute_group *grp)
395{
396 struct kernfs_node *parent;
397 struct attribute *const *attr;
398
399 parent = kernfs_find_and_get(kobj->sd, grp->name);
400 if (parent) {
401 for (attr = grp->attrs; *attr; ++attr)
402 kernfs_remove_by_name(parent, (*attr)->name);
403 kernfs_put(parent);
404 }
405}
406EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
407
408/**
409 * sysfs_add_link_to_group - add a symlink to an attribute group.
410 * @kobj: The kobject containing the group.
411 * @group_name: The name of the group.
412 * @target: The target kobject of the symlink to create.
413 * @link_name: The name of the symlink to create.
414 */
415int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
416 struct kobject *target, const char *link_name)
417{
418 struct kernfs_node *parent;
419 int error = 0;
420
421 parent = kernfs_find_and_get(kobj->sd, group_name);
422 if (!parent)
423 return -ENOENT;
424
425 error = sysfs_create_link_sd(parent, target, link_name);
426 kernfs_put(parent);
427
428 return error;
429}
430EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
431
432/**
433 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
434 * @kobj: The kobject containing the group.
435 * @group_name: The name of the group.
436 * @link_name: The name of the symlink to remove.
437 */
438void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
439 const char *link_name)
440{
441 struct kernfs_node *parent;
442
443 parent = kernfs_find_and_get(kobj->sd, group_name);
444 if (parent) {
445 kernfs_remove_by_name(parent, link_name);
446 kernfs_put(parent);
447 }
448}
449EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
450
451/**
452 * compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
453 * to a group or an attribute
454 * @kobj: The kobject containing the group.
455 * @target_kobj: The target kobject.
456 * @target_name: The name of the target group or attribute.
457 * @symlink_name: The name of the symlink file (target_name will be
458 * considered if symlink_name is NULL).
459 */
460int compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
461 struct kobject *target_kobj,
462 const char *target_name,
463 const char *symlink_name)
464{
465 struct kernfs_node *target;
466 struct kernfs_node *entry;
467 struct kernfs_node *link;
468
469 /*
470 * We don't own @target_kobj and it may be removed at any time.
471 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
472 * for details.
473 */
474 spin_lock(&sysfs_symlink_target_lock);
475 target = target_kobj->sd;
476 if (target)
477 kernfs_get(target);
478 spin_unlock(&sysfs_symlink_target_lock);
479 if (!target)
480 return -ENOENT;
481
482 entry = kernfs_find_and_get(target, target_name);
483 if (!entry) {
484 kernfs_put(target);
485 return -ENOENT;
486 }
487
488 if (!symlink_name)
489 symlink_name = target_name;
490
491 link = kernfs_create_link(kobj->sd, symlink_name, entry);
492 if (PTR_ERR(link) == -EEXIST)
493 sysfs_warn_dup(kobj->sd, symlink_name);
494
495 kernfs_put(entry);
496 kernfs_put(target);
497 return PTR_ERR_OR_ZERO(link);
498}
499EXPORT_SYMBOL_GPL(compat_only_sysfs_link_entry_to_kobj);
500
501static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
502 const struct attribute_group *grp,
503 struct iattr *newattrs)
504{
505 struct kernfs_node *kn;
506 int error;
507
508 if (grp->attrs) {
509 struct attribute *const *attr;
510
511 for (attr = grp->attrs; *attr; attr++) {
512 kn = kernfs_find_and_get(grp_kn, (*attr)->name);
513 if (!kn)
514 return -ENOENT;
515
516 error = kernfs_setattr(kn, newattrs);
517 kernfs_put(kn);
518 if (error)
519 return error;
520 }
521 }
522
523 if (grp->bin_attrs) {
524 struct bin_attribute *const *bin_attr;
525
526 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
527 kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
528 if (!kn)
529 return -ENOENT;
530
531 error = kernfs_setattr(kn, newattrs);
532 kernfs_put(kn);
533 if (error)
534 return error;
535 }
536 }
537
538 return 0;
539}
540
541/**
542 * sysfs_group_change_owner - change owner of an attribute group.
543 * @kobj: The kobject containing the group.
544 * @grp: The attribute group.
545 * @kuid: new owner's kuid
546 * @kgid: new owner's kgid
547 *
548 * Returns 0 on success or error code on failure.
549 */
550int sysfs_group_change_owner(struct kobject *kobj,
551 const struct attribute_group *grp, kuid_t kuid,
552 kgid_t kgid)
553{
554 struct kernfs_node *grp_kn;
555 int error;
556 struct iattr newattrs = {
557 .ia_valid = ATTR_UID | ATTR_GID,
558 .ia_uid = kuid,
559 .ia_gid = kgid,
560 };
561
562 if (!kobj->state_in_sysfs)
563 return -EINVAL;
564
565 if (grp->name) {
566 grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
567 } else {
568 kernfs_get(kobj->sd);
569 grp_kn = kobj->sd;
570 }
571 if (!grp_kn)
572 return -ENOENT;
573
574 error = kernfs_setattr(grp_kn, &newattrs);
575 if (!error)
576 error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
577
578 kernfs_put(grp_kn);
579
580 return error;
581}
582EXPORT_SYMBOL_GPL(sysfs_group_change_owner);
583
584/**
585 * sysfs_groups_change_owner - change owner of a set of attribute groups.
586 * @kobj: The kobject containing the groups.
587 * @groups: The attribute groups.
588 * @kuid: new owner's kuid
589 * @kgid: new owner's kgid
590 *
591 * Returns 0 on success or error code on failure.
592 */
593int sysfs_groups_change_owner(struct kobject *kobj,
594 const struct attribute_group **groups,
595 kuid_t kuid, kgid_t kgid)
596{
597 int error = 0, i;
598
599 if (!kobj->state_in_sysfs)
600 return -EINVAL;
601
602 if (!groups)
603 return 0;
604
605 for (i = 0; groups[i]; i++) {
606 error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
607 if (error)
608 break;
609 }
610
611 return error;
612}
613EXPORT_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, struct kobject *kobj,
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 sysfs_remove_bin_file(kobj, *bin_attr);
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 = 0;
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 error = sysfs_add_file_mode_ns(parent, *attr, false,
59 (*attr)->mode | mode,
60 NULL);
61 if (unlikely(error))
62 break;
63 }
64 if (error) {
65 remove_files(parent, kobj, grp);
66 goto exit;
67 }
68 }
69
70 if (grp->bin_attrs) {
71 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
72 if (update)
73 kernfs_remove_by_name(parent,
74 (*bin_attr)->attr.name);
75 error = sysfs_add_file_mode_ns(parent,
76 &(*bin_attr)->attr, true,
77 (*bin_attr)->attr.mode, NULL);
78 if (error)
79 break;
80 }
81 if (error)
82 remove_files(parent, kobj, grp);
83 }
84exit:
85 return error;
86}
87
88
89static int internal_create_group(struct kobject *kobj, int update,
90 const struct attribute_group *grp)
91{
92 struct kernfs_node *kn;
93 int error;
94
95 BUG_ON(!kobj || (!update && !kobj->sd));
96
97 /* Updates may happen before the object has been instantiated */
98 if (unlikely(update && !kobj->sd))
99 return -EINVAL;
100 if (!grp->attrs && !grp->bin_attrs) {
101 WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
102 kobj->name, grp->name ? "" : grp->name);
103 return -EINVAL;
104 }
105 if (grp->name) {
106 kn = kernfs_create_dir(kobj->sd, grp->name,
107 S_IRWXU | S_IRUGO | S_IXUGO, kobj);
108 if (IS_ERR(kn)) {
109 if (PTR_ERR(kn) == -EEXIST)
110 sysfs_warn_dup(kobj->sd, grp->name);
111 return PTR_ERR(kn);
112 }
113 } else
114 kn = kobj->sd;
115 kernfs_get(kn);
116 error = create_files(kn, kobj, grp, update);
117 if (error) {
118 if (grp->name)
119 kernfs_remove(kn);
120 }
121 kernfs_put(kn);
122 return error;
123}
124
125/**
126 * sysfs_create_group - given a directory kobject, create an attribute group
127 * @kobj: The kobject to create the group on
128 * @grp: The attribute group to create
129 *
130 * This function creates a group for the first time. It will explicitly
131 * warn and error if any of the attribute files being created already exist.
132 *
133 * Returns 0 on success or error.
134 */
135int sysfs_create_group(struct kobject *kobj,
136 const struct attribute_group *grp)
137{
138 return internal_create_group(kobj, 0, grp);
139}
140EXPORT_SYMBOL_GPL(sysfs_create_group);
141
142/**
143 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
144 * @kobj: The kobject to create the group on
145 * @groups: The attribute groups to create, NULL terminated
146 *
147 * This function creates a bunch of attribute groups. If an error occurs when
148 * creating a group, all previously created groups will be removed, unwinding
149 * everything back to the original state when this function was called.
150 * It will explicitly warn and error if any of the attribute files being
151 * created already exist.
152 *
153 * Returns 0 on success or error code from sysfs_create_group on error.
154 */
155int sysfs_create_groups(struct kobject *kobj,
156 const struct attribute_group **groups)
157{
158 int error = 0;
159 int i;
160
161 if (!groups)
162 return 0;
163
164 for (i = 0; groups[i]; i++) {
165 error = sysfs_create_group(kobj, groups[i]);
166 if (error) {
167 while (--i >= 0)
168 sysfs_remove_group(kobj, groups[i]);
169 break;
170 }
171 }
172 return error;
173}
174EXPORT_SYMBOL_GPL(sysfs_create_groups);
175
176/**
177 * sysfs_update_group - given a directory kobject, update an attribute group
178 * @kobj: The kobject to update the group on
179 * @grp: The attribute group to update
180 *
181 * This function updates an attribute group. Unlike
182 * sysfs_create_group(), it will explicitly not warn or error if any
183 * of the attribute files being created already exist. Furthermore,
184 * if the visibility of the files has changed through the is_visible()
185 * callback, it will update the permissions and add or remove the
186 * relevant files.
187 *
188 * The primary use for this function is to call it after making a change
189 * that affects group visibility.
190 *
191 * Returns 0 on success or error.
192 */
193int sysfs_update_group(struct kobject *kobj,
194 const struct attribute_group *grp)
195{
196 return internal_create_group(kobj, 1, grp);
197}
198EXPORT_SYMBOL_GPL(sysfs_update_group);
199
200/**
201 * sysfs_remove_group: remove a group from a kobject
202 * @kobj: kobject to remove the group from
203 * @grp: group to remove
204 *
205 * This function removes a group of attributes from a kobject. The attributes
206 * previously have to have been created for this group, otherwise it will fail.
207 */
208void sysfs_remove_group(struct kobject *kobj,
209 const struct attribute_group *grp)
210{
211 struct kernfs_node *parent = kobj->sd;
212 struct kernfs_node *kn;
213
214 if (grp->name) {
215 kn = kernfs_find_and_get(parent, grp->name);
216 if (!kn) {
217 WARN(!kn, KERN_WARNING
218 "sysfs group %p not found for kobject '%s'\n",
219 grp, kobject_name(kobj));
220 return;
221 }
222 } else {
223 kn = parent;
224 kernfs_get(kn);
225 }
226
227 remove_files(kn, kobj, grp);
228 if (grp->name)
229 kernfs_remove(kn);
230
231 kernfs_put(kn);
232}
233EXPORT_SYMBOL_GPL(sysfs_remove_group);
234
235/**
236 * sysfs_remove_groups - remove a list of groups
237 *
238 * @kobj: The kobject for the groups to be removed from
239 * @groups: NULL terminated list of groups to be removed
240 *
241 * If groups is not NULL, remove the specified groups from the kobject.
242 */
243void sysfs_remove_groups(struct kobject *kobj,
244 const struct attribute_group **groups)
245{
246 int i;
247
248 if (!groups)
249 return;
250 for (i = 0; groups[i]; i++)
251 sysfs_remove_group(kobj, groups[i]);
252}
253EXPORT_SYMBOL_GPL(sysfs_remove_groups);
254
255/**
256 * sysfs_merge_group - merge files into a pre-existing attribute group.
257 * @kobj: The kobject containing the group.
258 * @grp: The files to create and the attribute group they belong to.
259 *
260 * This function returns an error if the group doesn't exist or any of the
261 * files already exist in that group, in which case none of the new files
262 * are created.
263 */
264int sysfs_merge_group(struct kobject *kobj,
265 const struct attribute_group *grp)
266{
267 struct kernfs_node *parent;
268 int error = 0;
269 struct attribute *const *attr;
270 int i;
271
272 parent = kernfs_find_and_get(kobj->sd, grp->name);
273 if (!parent)
274 return -ENOENT;
275
276 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
277 error = sysfs_add_file(parent, *attr, false);
278 if (error) {
279 while (--i >= 0)
280 kernfs_remove_by_name(parent, (*--attr)->name);
281 }
282 kernfs_put(parent);
283
284 return error;
285}
286EXPORT_SYMBOL_GPL(sysfs_merge_group);
287
288/**
289 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
290 * @kobj: The kobject containing the group.
291 * @grp: The files to remove and the attribute group they belong to.
292 */
293void sysfs_unmerge_group(struct kobject *kobj,
294 const struct attribute_group *grp)
295{
296 struct kernfs_node *parent;
297 struct attribute *const *attr;
298
299 parent = kernfs_find_and_get(kobj->sd, grp->name);
300 if (parent) {
301 for (attr = grp->attrs; *attr; ++attr)
302 kernfs_remove_by_name(parent, (*attr)->name);
303 kernfs_put(parent);
304 }
305}
306EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
307
308/**
309 * sysfs_add_link_to_group - add a symlink to an attribute group.
310 * @kobj: The kobject containing the group.
311 * @group_name: The name of the group.
312 * @target: The target kobject of the symlink to create.
313 * @link_name: The name of the symlink to create.
314 */
315int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
316 struct kobject *target, const char *link_name)
317{
318 struct kernfs_node *parent;
319 int error = 0;
320
321 parent = kernfs_find_and_get(kobj->sd, group_name);
322 if (!parent)
323 return -ENOENT;
324
325 error = sysfs_create_link_sd(parent, target, link_name);
326 kernfs_put(parent);
327
328 return error;
329}
330EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
331
332/**
333 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
334 * @kobj: The kobject containing the group.
335 * @group_name: The name of the group.
336 * @link_name: The name of the symlink to remove.
337 */
338void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
339 const char *link_name)
340{
341 struct kernfs_node *parent;
342
343 parent = kernfs_find_and_get(kobj->sd, group_name);
344 if (parent) {
345 kernfs_remove_by_name(parent, link_name);
346 kernfs_put(parent);
347 }
348}
349EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);