Linux Audio

Check our new training course

Loading...
v3.1
 
  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 *
  7 * This file is released undert the GPL v2. 
  8 *
  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 "sysfs.h"
 17
 18
 19static void remove_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 20			 const struct attribute_group *grp)
 21{
 22	struct attribute *const* attr;
 23	int i;
 24
 25	for (i = 0, attr = grp->attrs; *attr; i++, attr++)
 26		sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
 
 
 
 
 27}
 28
 29static int create_files(struct sysfs_dirent *dir_sd, struct kobject *kobj,
 
 30			const struct attribute_group *grp, int update)
 31{
 32	struct attribute *const* attr;
 
 33	int error = 0, i;
 34
 35	for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
 36		mode_t mode = 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 37
 38		/* in update mode, we're changing the permissions or
 39		 * visibility.  Do this by first removing then
 40		 * re-adding (if required) the file */
 41		if (update)
 42			sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
 43		if (grp->is_visible) {
 44			mode = grp->is_visible(kobj, *attr, i);
 45			if (!mode)
 46				continue;
 47		}
 48		error = sysfs_add_file_mode(dir_sd, *attr, SYSFS_KOBJ_ATTR,
 49					    (*attr)->mode | mode);
 50		if (unlikely(error))
 51			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 52	}
 53	if (error)
 54		remove_files(dir_sd, kobj, grp);
 55	return error;
 56}
 57
 58
 59static int internal_create_group(struct kobject *kobj, int update,
 60				 const struct attribute_group *grp)
 61{
 62	struct sysfs_dirent *sd;
 
 
 63	int error;
 64
 65	BUG_ON(!kobj || (!update && !kobj->sd));
 
 66
 67	/* Updates may happen before the object has been instantiated */
 68	if (unlikely(update && !kobj->sd))
 69		return -EINVAL;
 70
 
 
 
 
 
 71	if (grp->name) {
 72		error = sysfs_create_subdir(kobj, grp->name, &sd);
 73		if (error)
 74			return error;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 75	} else
 76		sd = kobj->sd;
 77	sysfs_get(sd);
 78	error = create_files(sd, kobj, grp, update);
 79	if (error) {
 80		if (grp->name)
 81			sysfs_remove_subdir(sd);
 82	}
 83	sysfs_put(sd);
 
 
 
 
 84	return error;
 85}
 86
 87/**
 88 * sysfs_create_group - given a directory kobject, create an attribute group
 89 * @kobj:	The kobject to create the group on
 90 * @grp:	The attribute group to create
 91 *
 92 * This function creates a group for the first time.  It will explicitly
 93 * warn and error if any of the attribute files being created already exist.
 94 *
 95 * Returns 0 on success or error.
 96 */
 97int sysfs_create_group(struct kobject *kobj,
 98		       const struct attribute_group *grp)
 99{
100	return internal_create_group(kobj, 0, grp);
101}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
102
103/**
104 * sysfs_update_group - given a directory kobject, update an attribute group
105 * @kobj:	The kobject to update the group on
106 * @grp:	The attribute group to update
107 *
108 * This function updates an attribute group.  Unlike
109 * sysfs_create_group(), it will explicitly not warn or error if any
110 * of the attribute files being created already exist.  Furthermore,
111 * if the visibility of the files has changed through the is_visible()
112 * callback, it will update the permissions and add or remove the
113 * relevant files.
 
114 *
115 * The primary use for this function is to call it after making a change
116 * that affects group visibility.
117 *
118 * Returns 0 on success or error.
119 */
120int sysfs_update_group(struct kobject *kobj,
121		       const struct attribute_group *grp)
122{
123	return internal_create_group(kobj, 1, grp);
124}
 
125
126
127
128void sysfs_remove_group(struct kobject * kobj, 
129			const struct attribute_group * grp)
 
 
 
 
 
 
130{
131	struct sysfs_dirent *dir_sd = kobj->sd;
132	struct sysfs_dirent *sd;
133
134	if (grp->name) {
135		sd = sysfs_get_dirent(dir_sd, NULL, grp->name);
136		if (!sd) {
137			WARN(!sd, KERN_WARNING "sysfs group %p not found for "
138				"kobject '%s'\n", grp, kobject_name(kobj));
 
139			return;
140		}
141	} else
142		sd = sysfs_get(dir_sd);
 
 
143
144	remove_files(sd, kobj, grp);
145	if (grp->name)
146		sysfs_remove_subdir(sd);
147
148	sysfs_put(sd);
149}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
150
151/**
152 * sysfs_merge_group - merge files into a pre-existing attribute group.
153 * @kobj:	The kobject containing the group.
154 * @grp:	The files to create and the attribute group they belong to.
155 *
156 * This function returns an error if the group doesn't exist or any of the
157 * files already exist in that group, in which case none of the new files
158 * are created.
159 */
160int sysfs_merge_group(struct kobject *kobj,
161		       const struct attribute_group *grp)
162{
163	struct sysfs_dirent *dir_sd;
 
 
164	int error = 0;
165	struct attribute *const *attr;
166	int i;
167
168	dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
169	if (!dir_sd)
170		return -ENOENT;
171
 
 
172	for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
173		error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
 
174	if (error) {
175		while (--i >= 0)
176			sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name);
177	}
178	sysfs_put(dir_sd);
179
180	return error;
181}
182EXPORT_SYMBOL_GPL(sysfs_merge_group);
183
184/**
185 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
186 * @kobj:	The kobject containing the group.
187 * @grp:	The files to remove and the attribute group they belong to.
188 */
189void sysfs_unmerge_group(struct kobject *kobj,
190		       const struct attribute_group *grp)
191{
192	struct sysfs_dirent *dir_sd;
193	struct attribute *const *attr;
194
195	dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
196	if (dir_sd) {
197		for (attr = grp->attrs; *attr; ++attr)
198			sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
199		sysfs_put(dir_sd);
200	}
201}
202EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
203
 
 
 
 
 
 
 
 
 
 
 
 
204
205EXPORT_SYMBOL_GPL(sysfs_create_group);
206EXPORT_SYMBOL_GPL(sysfs_update_group);
207EXPORT_SYMBOL_GPL(sysfs_remove_group);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
v5.14.15
  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);