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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 umode_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 if (!grp->attrs) {
71 WARN(1, "sysfs: attrs not set by subsystem for group: %s/%s\n",
72 kobj->name, grp->name ? "" : grp->name);
73 return -EINVAL;
74 }
75 if (grp->name) {
76 error = sysfs_create_subdir(kobj, grp->name, &sd);
77 if (error)
78 return error;
79 } else
80 sd = kobj->sd;
81 sysfs_get(sd);
82 error = create_files(sd, kobj, grp, update);
83 if (error) {
84 if (grp->name)
85 sysfs_remove_subdir(sd);
86 }
87 sysfs_put(sd);
88 return error;
89}
90
91/**
92 * sysfs_create_group - given a directory kobject, create an attribute group
93 * @kobj: The kobject to create the group on
94 * @grp: The attribute group to create
95 *
96 * This function creates a group for the first time. It will explicitly
97 * warn and error if any of the attribute files being created already exist.
98 *
99 * Returns 0 on success or error.
100 */
101int sysfs_create_group(struct kobject *kobj,
102 const struct attribute_group *grp)
103{
104 return internal_create_group(kobj, 0, grp);
105}
106
107/**
108 * sysfs_update_group - given a directory kobject, update an attribute group
109 * @kobj: The kobject to update the group on
110 * @grp: The attribute group to update
111 *
112 * This function updates an attribute group. Unlike
113 * sysfs_create_group(), it will explicitly not warn or error if any
114 * of the attribute files being created already exist. Furthermore,
115 * if the visibility of the files has changed through the is_visible()
116 * callback, it will update the permissions and add or remove the
117 * relevant files.
118 *
119 * The primary use for this function is to call it after making a change
120 * that affects group visibility.
121 *
122 * Returns 0 on success or error.
123 */
124int sysfs_update_group(struct kobject *kobj,
125 const struct attribute_group *grp)
126{
127 return internal_create_group(kobj, 1, grp);
128}
129
130
131
132void sysfs_remove_group(struct kobject * kobj,
133 const struct attribute_group * grp)
134{
135 struct sysfs_dirent *dir_sd = kobj->sd;
136 struct sysfs_dirent *sd;
137
138 if (grp->name) {
139 sd = sysfs_get_dirent(dir_sd, NULL, grp->name);
140 if (!sd) {
141 WARN(!sd, KERN_WARNING "sysfs group %p not found for "
142 "kobject '%s'\n", grp, kobject_name(kobj));
143 return;
144 }
145 } else
146 sd = sysfs_get(dir_sd);
147
148 remove_files(sd, kobj, grp);
149 if (grp->name)
150 sysfs_remove_subdir(sd);
151
152 sysfs_put(sd);
153}
154
155/**
156 * sysfs_merge_group - merge files into a pre-existing attribute group.
157 * @kobj: The kobject containing the group.
158 * @grp: The files to create and the attribute group they belong to.
159 *
160 * This function returns an error if the group doesn't exist or any of the
161 * files already exist in that group, in which case none of the new files
162 * are created.
163 */
164int sysfs_merge_group(struct kobject *kobj,
165 const struct attribute_group *grp)
166{
167 struct sysfs_dirent *dir_sd;
168 int error = 0;
169 struct attribute *const *attr;
170 int i;
171
172 dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
173 if (!dir_sd)
174 return -ENOENT;
175
176 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
177 error = sysfs_add_file(dir_sd, *attr, SYSFS_KOBJ_ATTR);
178 if (error) {
179 while (--i >= 0)
180 sysfs_hash_and_remove(dir_sd, NULL, (*--attr)->name);
181 }
182 sysfs_put(dir_sd);
183
184 return error;
185}
186EXPORT_SYMBOL_GPL(sysfs_merge_group);
187
188/**
189 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
190 * @kobj: The kobject containing the group.
191 * @grp: The files to remove and the attribute group they belong to.
192 */
193void sysfs_unmerge_group(struct kobject *kobj,
194 const struct attribute_group *grp)
195{
196 struct sysfs_dirent *dir_sd;
197 struct attribute *const *attr;
198
199 dir_sd = sysfs_get_dirent(kobj->sd, NULL, grp->name);
200 if (dir_sd) {
201 for (attr = grp->attrs; *attr; ++attr)
202 sysfs_hash_and_remove(dir_sd, NULL, (*attr)->name);
203 sysfs_put(dir_sd);
204 }
205}
206EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
207
208
209EXPORT_SYMBOL_GPL(sysfs_create_group);
210EXPORT_SYMBOL_GPL(sysfs_update_group);
211EXPORT_SYMBOL_GPL(sysfs_remove_group);
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 "sysfs.h"
17
18
19static void remove_files(struct kernfs_node *parent,
20 const struct attribute_group *grp)
21{
22 struct attribute *const *attr;
23 struct bin_attribute *const *bin_attr;
24
25 if (grp->attrs)
26 for (attr = grp->attrs; *attr; attr++)
27 kernfs_remove_by_name(parent, (*attr)->name);
28 if (grp->bin_attrs)
29 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
30 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
31}
32
33static int create_files(struct kernfs_node *parent, struct kobject *kobj,
34 kuid_t uid, kgid_t gid,
35 const struct attribute_group *grp, int update)
36{
37 struct attribute *const *attr;
38 struct bin_attribute *const *bin_attr;
39 int error = 0, i;
40
41 if (grp->attrs) {
42 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
43 umode_t mode = (*attr)->mode;
44
45 /*
46 * In update mode, we're changing the permissions or
47 * visibility. Do this by first removing then
48 * re-adding (if required) the file.
49 */
50 if (update)
51 kernfs_remove_by_name(parent, (*attr)->name);
52 if (grp->is_visible) {
53 mode = grp->is_visible(kobj, *attr, i);
54 if (!mode)
55 continue;
56 }
57
58 WARN(mode & ~(SYSFS_PREALLOC | 0664),
59 "Attribute %s: Invalid permissions 0%o\n",
60 (*attr)->name, mode);
61
62 mode &= SYSFS_PREALLOC | 0664;
63 error = sysfs_add_file_mode_ns(parent, *attr, false,
64 mode, uid, gid, NULL);
65 if (unlikely(error))
66 break;
67 }
68 if (error) {
69 remove_files(parent, grp);
70 goto exit;
71 }
72 }
73
74 if (grp->bin_attrs) {
75 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
76 umode_t mode = (*bin_attr)->attr.mode;
77
78 if (update)
79 kernfs_remove_by_name(parent,
80 (*bin_attr)->attr.name);
81 if (grp->is_bin_visible) {
82 mode = grp->is_bin_visible(kobj, *bin_attr, i);
83 if (!mode)
84 continue;
85 }
86
87 WARN(mode & ~(SYSFS_PREALLOC | 0664),
88 "Attribute %s: Invalid permissions 0%o\n",
89 (*bin_attr)->attr.name, mode);
90
91 mode &= SYSFS_PREALLOC | 0664;
92 error = sysfs_add_file_mode_ns(parent,
93 &(*bin_attr)->attr, true,
94 mode,
95 uid, gid, 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, false,
343 (*attr)->mode, 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 */
424int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
425 struct kobject *target_kobj,
426 const char *target_name)
427{
428 struct kernfs_node *target;
429 struct kernfs_node *entry;
430 struct kernfs_node *link;
431
432 /*
433 * We don't own @target_kobj and it may be removed at any time.
434 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
435 * for details.
436 */
437 spin_lock(&sysfs_symlink_target_lock);
438 target = target_kobj->sd;
439 if (target)
440 kernfs_get(target);
441 spin_unlock(&sysfs_symlink_target_lock);
442 if (!target)
443 return -ENOENT;
444
445 entry = kernfs_find_and_get(target_kobj->sd, target_name);
446 if (!entry) {
447 kernfs_put(target);
448 return -ENOENT;
449 }
450
451 link = kernfs_create_link(kobj->sd, target_name, entry);
452 if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
453 sysfs_warn_dup(kobj->sd, target_name);
454
455 kernfs_put(entry);
456 kernfs_put(target);
457 return PTR_ERR_OR_ZERO(link);
458}
459EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);