1 // SPDX-License-Identifier: GPL-2.0
3 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
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
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>
20 static void remove_files(struct kernfs_node *parent,
21 const struct attribute_group *grp)
23 struct attribute *const *attr;
24 struct bin_attribute *const *bin_attr;
27 for (attr = grp->attrs; *attr; attr++)
28 kernfs_remove_by_name(parent, (*attr)->name);
30 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
31 kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
34 static umode_t __first_visible(const struct attribute_group *grp, struct kobject *kobj)
36 if (grp->attrs && grp->attrs[0] && grp->is_visible)
37 return grp->is_visible(kobj, grp->attrs[0], 0);
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);
45 static 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)
49 struct attribute *const *attr;
50 struct bin_attribute *const *bin_attr;
54 for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
55 umode_t mode = (*attr)->mode;
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.
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;
71 WARN(mode & ~(SYSFS_PREALLOC | 0664),
72 "Attribute %s: Invalid permissions 0%o\n",
75 mode &= SYSFS_PREALLOC | 0664;
76 error = sysfs_add_file_mode_ns(parent, *attr, mode, uid,
82 remove_files(parent, grp);
88 for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
89 umode_t mode = (*bin_attr)->attr.mode;
92 kernfs_remove_by_name(parent,
93 (*bin_attr)->attr.name);
94 if (grp->is_bin_visible) {
95 mode = grp->is_bin_visible(kobj, *bin_attr, i);
96 mode &= ~SYSFS_GROUP_INVISIBLE;
101 WARN(mode & ~(SYSFS_PREALLOC | 0664),
102 "Attribute %s: Invalid permissions 0%o\n",
103 (*bin_attr)->attr.name, mode);
105 mode &= SYSFS_PREALLOC | 0664;
106 error = sysfs_add_bin_file_mode_ns(parent, *bin_attr,
113 remove_files(parent, grp);
120 static int internal_create_group(struct kobject *kobj, int update,
121 const struct attribute_group *grp)
123 struct kernfs_node *kn;
128 if (WARN_ON(!kobj || (!update && !kobj->sd)))
131 /* Updates may happen before the object has been instantiated */
132 if (unlikely(update && !kobj->sd))
135 if (!grp->attrs && !grp->bin_attrs) {
136 pr_debug("sysfs: (bin_)attrs not set by subsystem for group: %s/%s, skipping\n",
137 kobj->name, grp->name ?: "");
141 kobject_get_ownership(kobj, &uid, &gid);
143 umode_t mode = __first_visible(grp, kobj);
145 if (mode & SYSFS_GROUP_INVISIBLE)
148 mode = S_IRWXU | S_IRUGO | S_IXUGO;
151 kn = kernfs_find_and_get(kobj->sd, grp->name);
153 pr_debug("attr grp %s/%s not created yet\n",
154 kobj->name, grp->name);
155 /* may have been invisible prior to this update */
158 sysfs_remove_group(kobj, grp);
167 kn = kernfs_create_dir_ns(kobj->sd, grp->name, mode,
168 uid, gid, kobj, NULL);
170 if (PTR_ERR(kn) == -EEXIST)
171 sysfs_warn_dup(kobj->sd, grp->name);
180 error = create_files(kn, kobj, uid, gid, grp, update);
187 if (grp->name && update)
194 * sysfs_create_group - given a directory kobject, create an attribute group
195 * @kobj: The kobject to create the group on
196 * @grp: The attribute group to create
198 * This function creates a group for the first time. It will explicitly
199 * warn and error if any of the attribute files being created already exist.
201 * Returns 0 on success or error code on failure.
203 int sysfs_create_group(struct kobject *kobj,
204 const struct attribute_group *grp)
206 return internal_create_group(kobj, 0, grp);
208 EXPORT_SYMBOL_GPL(sysfs_create_group);
210 static int internal_create_groups(struct kobject *kobj, int update,
211 const struct attribute_group **groups)
219 for (i = 0; groups[i]; i++) {
220 error = internal_create_group(kobj, update, groups[i]);
223 sysfs_remove_group(kobj, groups[i]);
231 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
232 * @kobj: The kobject to create the group on
233 * @groups: The attribute groups to create, NULL terminated
235 * This function creates a bunch of attribute groups. If an error occurs when
236 * creating a group, all previously created groups will be removed, unwinding
237 * everything back to the original state when this function was called.
238 * It will explicitly warn and error if any of the attribute files being
239 * created already exist.
241 * Returns 0 on success or error code from sysfs_create_group on failure.
243 int sysfs_create_groups(struct kobject *kobj,
244 const struct attribute_group **groups)
246 return internal_create_groups(kobj, 0, groups);
248 EXPORT_SYMBOL_GPL(sysfs_create_groups);
251 * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
252 * @kobj: The kobject to update the group on
253 * @groups: The attribute groups to update, NULL terminated
255 * This function update a bunch of attribute groups. If an error occurs when
256 * updating a group, all previously updated groups will be removed together
257 * with already existing (not updated) attributes.
259 * Returns 0 on success or error code from sysfs_update_group on failure.
261 int sysfs_update_groups(struct kobject *kobj,
262 const struct attribute_group **groups)
264 return internal_create_groups(kobj, 1, groups);
266 EXPORT_SYMBOL_GPL(sysfs_update_groups);
269 * sysfs_update_group - given a directory kobject, update an attribute group
270 * @kobj: The kobject to update the group on
271 * @grp: The attribute group to update
273 * This function updates an attribute group. Unlike
274 * sysfs_create_group(), it will explicitly not warn or error if any
275 * of the attribute files being created already exist. Furthermore,
276 * if the visibility of the files has changed through the is_visible()
277 * callback, it will update the permissions and add or remove the
278 * relevant files. Changing a group's name (subdirectory name under
279 * kobj's directory in sysfs) is not allowed.
281 * The primary use for this function is to call it after making a change
282 * that affects group visibility.
284 * Returns 0 on success or error code on failure.
286 int sysfs_update_group(struct kobject *kobj,
287 const struct attribute_group *grp)
289 return internal_create_group(kobj, 1, grp);
291 EXPORT_SYMBOL_GPL(sysfs_update_group);
294 * sysfs_remove_group: remove a group from a kobject
295 * @kobj: kobject to remove the group from
296 * @grp: group to remove
298 * This function removes a group of attributes from a kobject. The attributes
299 * previously have to have been created for this group, otherwise it will fail.
301 void sysfs_remove_group(struct kobject *kobj,
302 const struct attribute_group *grp)
304 struct kernfs_node *parent = kobj->sd;
305 struct kernfs_node *kn;
308 kn = kernfs_find_and_get(parent, grp->name);
310 pr_debug("sysfs group '%s' not found for kobject '%s'\n",
311 grp->name, kobject_name(kobj));
319 remove_files(kn, grp);
325 EXPORT_SYMBOL_GPL(sysfs_remove_group);
328 * sysfs_remove_groups - remove a list of groups
330 * @kobj: The kobject for the groups to be removed from
331 * @groups: NULL terminated list of groups to be removed
333 * If groups is not NULL, remove the specified groups from the kobject.
335 void sysfs_remove_groups(struct kobject *kobj,
336 const struct attribute_group **groups)
342 for (i = 0; groups[i]; i++)
343 sysfs_remove_group(kobj, groups[i]);
345 EXPORT_SYMBOL_GPL(sysfs_remove_groups);
348 * sysfs_merge_group - merge files into a pre-existing named attribute group.
349 * @kobj: The kobject containing the group.
350 * @grp: The files to create and the attribute group they belong to.
352 * This function returns an error if the group doesn't exist, the .name field is
353 * NULL or any of the files already exist in that group, in which case none of
354 * the new files are created.
356 int sysfs_merge_group(struct kobject *kobj,
357 const struct attribute_group *grp)
359 struct kernfs_node *parent;
363 struct attribute *const *attr;
366 parent = kernfs_find_and_get(kobj->sd, grp->name);
370 kobject_get_ownership(kobj, &uid, &gid);
372 for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
373 error = sysfs_add_file_mode_ns(parent, *attr, (*attr)->mode,
377 kernfs_remove_by_name(parent, (*--attr)->name);
383 EXPORT_SYMBOL_GPL(sysfs_merge_group);
386 * sysfs_unmerge_group - remove files from a pre-existing named attribute group.
387 * @kobj: The kobject containing the group.
388 * @grp: The files to remove and the attribute group they belong to.
390 void sysfs_unmerge_group(struct kobject *kobj,
391 const struct attribute_group *grp)
393 struct kernfs_node *parent;
394 struct attribute *const *attr;
396 parent = kernfs_find_and_get(kobj->sd, grp->name);
398 for (attr = grp->attrs; *attr; ++attr)
399 kernfs_remove_by_name(parent, (*attr)->name);
403 EXPORT_SYMBOL_GPL(sysfs_unmerge_group);
406 * sysfs_add_link_to_group - add a symlink to an attribute group.
407 * @kobj: The kobject containing the group.
408 * @group_name: The name of the group.
409 * @target: The target kobject of the symlink to create.
410 * @link_name: The name of the symlink to create.
412 int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
413 struct kobject *target, const char *link_name)
415 struct kernfs_node *parent;
418 parent = kernfs_find_and_get(kobj->sd, group_name);
422 error = sysfs_create_link_sd(parent, target, link_name);
427 EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);
430 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
431 * @kobj: The kobject containing the group.
432 * @group_name: The name of the group.
433 * @link_name: The name of the symlink to remove.
435 void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
436 const char *link_name)
438 struct kernfs_node *parent;
440 parent = kernfs_find_and_get(kobj->sd, group_name);
442 kernfs_remove_by_name(parent, link_name);
446 EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
449 * compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
450 * to a group or an attribute
451 * @kobj: The kobject containing the group.
452 * @target_kobj: The target kobject.
453 * @target_name: The name of the target group or attribute.
454 * @symlink_name: The name of the symlink file (target_name will be
455 * considered if symlink_name is NULL).
457 int compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
458 struct kobject *target_kobj,
459 const char *target_name,
460 const char *symlink_name)
462 struct kernfs_node *target;
463 struct kernfs_node *entry;
464 struct kernfs_node *link;
467 * We don't own @target_kobj and it may be removed at any time.
468 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
471 spin_lock(&sysfs_symlink_target_lock);
472 target = target_kobj->sd;
475 spin_unlock(&sysfs_symlink_target_lock);
479 entry = kernfs_find_and_get(target, target_name);
486 symlink_name = target_name;
488 link = kernfs_create_link(kobj->sd, symlink_name, entry);
489 if (PTR_ERR(link) == -EEXIST)
490 sysfs_warn_dup(kobj->sd, symlink_name);
494 return PTR_ERR_OR_ZERO(link);
496 EXPORT_SYMBOL_GPL(compat_only_sysfs_link_entry_to_kobj);
498 static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
499 const struct attribute_group *grp,
500 struct iattr *newattrs)
502 struct kernfs_node *kn;
506 struct attribute *const *attr;
508 for (attr = grp->attrs; *attr; attr++) {
509 kn = kernfs_find_and_get(grp_kn, (*attr)->name);
513 error = kernfs_setattr(kn, newattrs);
520 if (grp->bin_attrs) {
521 struct bin_attribute *const *bin_attr;
523 for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
524 kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
528 error = kernfs_setattr(kn, newattrs);
539 * sysfs_group_change_owner - change owner of an attribute group.
540 * @kobj: The kobject containing the group.
541 * @grp: The attribute group.
542 * @kuid: new owner's kuid
543 * @kgid: new owner's kgid
545 * Returns 0 on success or error code on failure.
547 int sysfs_group_change_owner(struct kobject *kobj,
548 const struct attribute_group *grp, kuid_t kuid,
551 struct kernfs_node *grp_kn;
553 struct iattr newattrs = {
554 .ia_valid = ATTR_UID | ATTR_GID,
559 if (!kobj->state_in_sysfs)
563 grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
565 kernfs_get(kobj->sd);
571 error = kernfs_setattr(grp_kn, &newattrs);
573 error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);
579 EXPORT_SYMBOL_GPL(sysfs_group_change_owner);
582 * sysfs_groups_change_owner - change owner of a set of attribute groups.
583 * @kobj: The kobject containing the groups.
584 * @groups: The attribute groups.
585 * @kuid: new owner's kuid
586 * @kgid: new owner's kgid
588 * Returns 0 on success or error code on failure.
590 int sysfs_groups_change_owner(struct kobject *kobj,
591 const struct attribute_group **groups,
592 kuid_t kuid, kgid_t kgid)
596 if (!kobj->state_in_sysfs)
602 for (i = 0; groups[i]; i++) {
603 error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
610 EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);