Line data Source code
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 :
20 84 : static void remove_files(struct kernfs_node *parent,
21 : const struct attribute_group *grp)
22 : {
23 84 : struct attribute *const *attr;
24 84 : struct bin_attribute *const *bin_attr;
25 :
26 84 : if (grp->attrs)
27 508 : for (attr = grp->attrs; *attr; attr++)
28 424 : kernfs_remove_by_name(parent, (*attr)->name);
29 84 : if (grp->bin_attrs)
30 0 : for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
31 0 : kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
32 84 : }
33 :
34 403 : static 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 : {
38 403 : struct attribute *const *attr;
39 403 : struct bin_attribute *const *bin_attr;
40 403 : int error = 0, i;
41 :
42 403 : if (grp->attrs) {
43 6610 : for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
44 6207 : 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 6207 : if (update)
52 36 : kernfs_remove_by_name(parent, (*attr)->name);
53 6207 : if (grp->is_visible) {
54 714 : mode = grp->is_visible(kobj, *attr, i);
55 714 : if (!mode)
56 99 : continue;
57 : }
58 :
59 6108 : WARN(mode & ~(SYSFS_PREALLOC | 0664),
60 : "Attribute %s: Invalid permissions 0%o\n",
61 : (*attr)->name, mode);
62 :
63 6108 : mode &= SYSFS_PREALLOC | 0664;
64 6108 : error = sysfs_add_file_mode_ns(parent, *attr, false,
65 : mode, uid, gid, NULL);
66 6108 : if (unlikely(error))
67 : break;
68 : }
69 403 : if (error) {
70 0 : remove_files(parent, grp);
71 0 : goto exit;
72 : }
73 : }
74 :
75 403 : if (grp->bin_attrs) {
76 2 : for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
77 1 : umode_t mode = (*bin_attr)->attr.mode;
78 :
79 1 : if (update)
80 0 : kernfs_remove_by_name(parent,
81 : (*bin_attr)->attr.name);
82 1 : if (grp->is_bin_visible) {
83 0 : mode = grp->is_bin_visible(kobj, *bin_attr, i);
84 0 : if (!mode)
85 0 : continue;
86 : }
87 :
88 1 : WARN(mode & ~(SYSFS_PREALLOC | 0664),
89 : "Attribute %s: Invalid permissions 0%o\n",
90 : (*bin_attr)->attr.name, mode);
91 :
92 1 : mode &= SYSFS_PREALLOC | 0664;
93 2 : error = sysfs_add_file_mode_ns(parent,
94 1 : &(*bin_attr)->attr, true,
95 : mode,
96 : uid, gid, NULL);
97 1 : if (error)
98 : break;
99 : }
100 1 : if (error)
101 0 : remove_files(parent, grp);
102 : }
103 403 : exit:
104 403 : return error;
105 : }
106 :
107 :
108 403 : static int internal_create_group(struct kobject *kobj, int update,
109 : const struct attribute_group *grp)
110 : {
111 403 : struct kernfs_node *kn;
112 403 : kuid_t uid;
113 403 : kgid_t gid;
114 403 : int error;
115 :
116 806 : if (WARN_ON(!kobj || (!update && !kobj->sd)))
117 : return -EINVAL;
118 :
119 : /* Updates may happen before the object has been instantiated */
120 403 : if (unlikely(update && !kobj->sd))
121 : return -EINVAL;
122 403 : if (!grp->attrs && !grp->bin_attrs) {
123 0 : WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
124 : kobj->name, grp->name ?: "");
125 0 : return -EINVAL;
126 : }
127 403 : kobject_get_ownership(kobj, &uid, &gid);
128 403 : if (grp->name) {
129 148 : if (update) {
130 14 : kn = kernfs_find_and_get(kobj->sd, grp->name);
131 14 : if (!kn) {
132 0 : pr_warn("Can't update unknown attr grp name: %s/%s\n",
133 : kobj->name, grp->name);
134 0 : return -EINVAL;
135 : }
136 : } else {
137 134 : kn = kernfs_create_dir_ns(kobj->sd, grp->name,
138 : S_IRWXU | S_IRUGO | S_IXUGO,
139 : uid, gid, kobj, NULL);
140 134 : if (IS_ERR(kn)) {
141 0 : if (PTR_ERR(kn) == -EEXIST)
142 0 : sysfs_warn_dup(kobj->sd, grp->name);
143 0 : return PTR_ERR(kn);
144 : }
145 : }
146 : } else
147 255 : kn = kobj->sd;
148 403 : kernfs_get(kn);
149 403 : error = create_files(kn, kobj, uid, gid, grp, update);
150 403 : if (error) {
151 0 : if (grp->name)
152 0 : kernfs_remove(kn);
153 : }
154 403 : kernfs_put(kn);
155 :
156 403 : if (grp->name && update)
157 14 : 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 : */
172 285 : int sysfs_create_group(struct kobject *kobj,
173 : const struct attribute_group *grp)
174 : {
175 285 : return internal_create_group(kobj, 0, grp);
176 : }
177 : EXPORT_SYMBOL_GPL(sysfs_create_group);
178 :
179 938 : static int internal_create_groups(struct kobject *kobj, int update,
180 : const struct attribute_group **groups)
181 : {
182 938 : int error = 0;
183 938 : int i;
184 :
185 938 : if (!groups)
186 : return 0;
187 :
188 222 : for (i = 0; groups[i]; i++) {
189 118 : error = internal_create_group(kobj, update, groups[i]);
190 118 : if (error) {
191 0 : while (--i >= 0)
192 0 : 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 : */
212 936 : int sysfs_create_groups(struct kobject *kobj,
213 : const struct attribute_group **groups)
214 : {
215 936 : return internal_create_groups(kobj, 0, groups);
216 : }
217 : EXPORT_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 : */
230 2 : int sysfs_update_groups(struct kobject *kobj,
231 : const struct attribute_group **groups)
232 : {
233 2 : return internal_create_groups(kobj, 1, groups);
234 : }
235 : EXPORT_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 : */
255 0 : int sysfs_update_group(struct kobject *kobj,
256 : const struct attribute_group *grp)
257 : {
258 0 : return internal_create_group(kobj, 1, grp);
259 : }
260 : EXPORT_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 : */
270 84 : void sysfs_remove_group(struct kobject *kobj,
271 : const struct attribute_group *grp)
272 : {
273 84 : struct kernfs_node *parent = kobj->sd;
274 84 : struct kernfs_node *kn;
275 :
276 84 : if (grp->name) {
277 84 : kn = kernfs_find_and_get(parent, grp->name);
278 84 : if (!kn) {
279 0 : WARN(!kn, KERN_WARNING
280 : "sysfs group '%s' not found for kobject '%s'\n",
281 : grp->name, kobject_name(kobj));
282 0 : return;
283 : }
284 : } else {
285 0 : kn = parent;
286 0 : kernfs_get(kn);
287 : }
288 :
289 84 : remove_files(kn, grp);
290 84 : if (grp->name)
291 84 : kernfs_remove(kn);
292 :
293 84 : kernfs_put(kn);
294 : }
295 : EXPORT_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 : */
305 3 : void sysfs_remove_groups(struct kobject *kobj,
306 : const struct attribute_group **groups)
307 : {
308 3 : int i;
309 :
310 3 : if (!groups)
311 : return;
312 0 : for (i = 0; groups[i]; i++)
313 0 : sysfs_remove_group(kobj, groups[i]);
314 : }
315 : EXPORT_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 : */
326 0 : int sysfs_merge_group(struct kobject *kobj,
327 : const struct attribute_group *grp)
328 : {
329 0 : struct kernfs_node *parent;
330 0 : kuid_t uid;
331 0 : kgid_t gid;
332 0 : int error = 0;
333 0 : struct attribute *const *attr;
334 0 : int i;
335 :
336 0 : parent = kernfs_find_and_get(kobj->sd, grp->name);
337 0 : if (!parent)
338 : return -ENOENT;
339 :
340 0 : kobject_get_ownership(kobj, &uid, &gid);
341 :
342 0 : for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
343 0 : error = sysfs_add_file_mode_ns(parent, *attr, false,
344 0 : (*attr)->mode, uid, gid, NULL);
345 0 : if (error) {
346 0 : while (--i >= 0)
347 0 : kernfs_remove_by_name(parent, (*--attr)->name);
348 : }
349 0 : kernfs_put(parent);
350 :
351 0 : return error;
352 : }
353 : EXPORT_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 : */
360 0 : void sysfs_unmerge_group(struct kobject *kobj,
361 : const struct attribute_group *grp)
362 : {
363 0 : struct kernfs_node *parent;
364 0 : struct attribute *const *attr;
365 :
366 0 : parent = kernfs_find_and_get(kobj->sd, grp->name);
367 0 : if (parent) {
368 0 : for (attr = grp->attrs; *attr; ++attr)
369 0 : kernfs_remove_by_name(parent, (*attr)->name);
370 0 : kernfs_put(parent);
371 : }
372 0 : }
373 : EXPORT_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 : */
382 0 : int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
383 : struct kobject *target, const char *link_name)
384 : {
385 0 : struct kernfs_node *parent;
386 0 : int error = 0;
387 :
388 0 : parent = kernfs_find_and_get(kobj->sd, group_name);
389 0 : if (!parent)
390 : return -ENOENT;
391 :
392 0 : error = sysfs_create_link_sd(parent, target, link_name);
393 0 : kernfs_put(parent);
394 :
395 0 : return error;
396 : }
397 : EXPORT_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 : */
405 0 : void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
406 : const char *link_name)
407 : {
408 0 : struct kernfs_node *parent;
409 :
410 0 : parent = kernfs_find_and_get(kobj->sd, group_name);
411 0 : if (parent) {
412 0 : kernfs_remove_by_name(parent, link_name);
413 0 : kernfs_put(parent);
414 : }
415 0 : }
416 : EXPORT_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 : */
427 0 : int 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 0 : struct kernfs_node *target;
433 0 : struct kernfs_node *entry;
434 0 : 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 0 : spin_lock(&sysfs_symlink_target_lock);
442 0 : target = target_kobj->sd;
443 0 : if (target)
444 0 : kernfs_get(target);
445 0 : spin_unlock(&sysfs_symlink_target_lock);
446 0 : if (!target)
447 : return -ENOENT;
448 :
449 0 : entry = kernfs_find_and_get(target_kobj->sd, target_name);
450 0 : if (!entry) {
451 0 : kernfs_put(target);
452 0 : return -ENOENT;
453 : }
454 :
455 0 : if (!symlink_name)
456 0 : symlink_name = target_name;
457 :
458 0 : link = kernfs_create_link(kobj->sd, symlink_name, entry);
459 0 : if (PTR_ERR(link) == -EEXIST)
460 0 : sysfs_warn_dup(kobj->sd, symlink_name);
461 :
462 0 : kernfs_put(entry);
463 0 : kernfs_put(target);
464 0 : return PTR_ERR_OR_ZERO(link);
465 : }
466 : EXPORT_SYMBOL_GPL(compat_only_sysfs_link_entry_to_kobj);
467 :
468 0 : static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
469 : const struct attribute_group *grp,
470 : struct iattr *newattrs)
471 : {
472 0 : struct kernfs_node *kn;
473 0 : int error;
474 :
475 0 : if (grp->attrs) {
476 : struct attribute *const *attr;
477 :
478 0 : for (attr = grp->attrs; *attr; attr++) {
479 0 : kn = kernfs_find_and_get(grp_kn, (*attr)->name);
480 0 : if (!kn)
481 : return -ENOENT;
482 :
483 0 : error = kernfs_setattr(kn, newattrs);
484 0 : kernfs_put(kn);
485 0 : if (error)
486 0 : return error;
487 : }
488 : }
489 :
490 0 : if (grp->bin_attrs) {
491 : struct bin_attribute *const *bin_attr;
492 :
493 0 : for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
494 0 : kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
495 0 : if (!kn)
496 : return -ENOENT;
497 :
498 0 : error = kernfs_setattr(kn, newattrs);
499 0 : kernfs_put(kn);
500 0 : if (error)
501 0 : 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 : */
517 0 : int sysfs_group_change_owner(struct kobject *kobj,
518 : const struct attribute_group *grp, kuid_t kuid,
519 : kgid_t kgid)
520 : {
521 0 : struct kernfs_node *grp_kn;
522 0 : int error;
523 0 : struct iattr newattrs = {
524 : .ia_valid = ATTR_UID | ATTR_GID,
525 : .ia_uid = kuid,
526 : .ia_gid = kgid,
527 : };
528 :
529 0 : if (!kobj->state_in_sysfs)
530 : return -EINVAL;
531 :
532 0 : if (grp->name) {
533 0 : grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
534 : } else {
535 0 : kernfs_get(kobj->sd);
536 0 : grp_kn = kobj->sd;
537 : }
538 0 : if (!grp_kn)
539 : return -ENOENT;
540 :
541 0 : error = kernfs_setattr(grp_kn, &newattrs);
542 0 : if (!error)
543 0 : error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
544 :
545 0 : kernfs_put(grp_kn);
546 :
547 0 : return error;
548 : }
549 : EXPORT_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 : */
560 0 : int sysfs_groups_change_owner(struct kobject *kobj,
561 : const struct attribute_group **groups,
562 : kuid_t kuid, kgid_t kgid)
563 : {
564 0 : int error = 0, i;
565 :
566 0 : if (!kobj->state_in_sysfs)
567 : return -EINVAL;
568 :
569 0 : if (!groups)
570 : return 0;
571 :
572 0 : for (i = 0; groups[i]; i++) {
573 0 : error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
574 0 : if (error)
575 : break;
576 : }
577 :
578 : return error;
579 : }
580 : EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);
|
