summaryrefslogtreecommitdiff
path: root/fs/sysfs/group.c
blob: 5afe0e7ff7cd1c486078caa7d2660491456b184d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
// SPDX-License-Identifier: GPL-2.0
/*
 * fs/sysfs/group.c - Operations for adding/removing multiple files at once.
 *
 * Copyright (c) 2003 Patrick Mochel
 * Copyright (c) 2003 Open Source Development Lab
 * Copyright (c) 2013 Greg Kroah-Hartman
 * Copyright (c) 2013 The Linux Foundation
 */

#include <linux/kobject.h>
#include <linux/module.h>
#include <linux/dcache.h>
#include <linux/namei.h>
#include <linux/err.h>
#include <linux/fs.h>
#include "sysfs.h"


static void remove_files(struct kernfs_node *parent,
			 const struct attribute_group *grp)
{
	struct attribute *const *attr;
	struct bin_attribute *const *bin_attr;

	if (grp->attrs)
		for (attr = grp->attrs; *attr; attr++)
			kernfs_remove_by_name(parent, (*attr)->name);
	if (grp->bin_attrs)
		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++)
			kernfs_remove_by_name(parent, (*bin_attr)->attr.name);
}

static int create_files(struct kernfs_node *parent, struct kobject *kobj,
			kuid_t uid, kgid_t gid,
			const struct attribute_group *grp, int update)
{
	struct attribute *const *attr;
	struct bin_attribute *const *bin_attr;
	int error = 0, i;

	if (grp->attrs) {
		for (i = 0, attr = grp->attrs; *attr && !error; i++, attr++) {
			umode_t mode = (*attr)->mode;

			/*
			 * In update mode, we're changing the permissions or
			 * visibility.  Do this by first removing then
			 * re-adding (if required) the file.
			 */
			if (update)
				kernfs_remove_by_name(parent, (*attr)->name);
			if (grp->is_visible) {
				mode = grp->is_visible(kobj, *attr, i);
				if (!mode)
					continue;
			}

			WARN(mode & ~(SYSFS_PREALLOC | 0664),
			     "Attribute %s: Invalid permissions 0%o\n",
			     (*attr)->name, mode);

			mode &= SYSFS_PREALLOC | 0664;
			error = sysfs_add_file_mode_ns(parent, *attr, false,
						       mode, uid, gid, NULL);
			if (unlikely(error))
				break;
		}
		if (error) {
			remove_files(parent, grp);
			goto exit;
		}
	}

	if (grp->bin_attrs) {
		for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
			umode_t mode = (*bin_attr)->attr.mode;

			if (update)
				kernfs_remove_by_name(parent,
						(*bin_attr)->attr.name);
			if (grp->is_bin_visible) {
				mode = grp->is_bin_visible(kobj, *bin_attr, i);
				if (!mode)
					continue;
			}

			WARN(mode & ~(SYSFS_PREALLOC | 0664),
			     "Attribute %s: Invalid permissions 0%o\n",
			     (*bin_attr)->attr.name, mode);

			mode &= SYSFS_PREALLOC | 0664;
			error = sysfs_add_file_mode_ns(parent,
					&(*bin_attr)->attr, true,
					mode,
					uid, gid, NULL);
			if (error)
				break;
		}
		if (error)
			remove_files(parent, grp);
	}
exit:
	return error;
}


static int internal_create_group(struct kobject *kobj, int update,
				 const struct attribute_group *grp)
{
	struct kernfs_node *kn;
	kuid_t uid;
	kgid_t gid;
	int error;

	if (WARN_ON(!kobj || (!update && !kobj->sd)))
		return -EINVAL;

	/* Updates may happen before the object has been instantiated */
	if (unlikely(update && !kobj->sd))
		return -EINVAL;
	if (!grp->attrs && !grp->bin_attrs) {
		WARN(1, "sysfs: (bin_)attrs not set by subsystem for group: %s/%s\n",
			kobj->name, grp->name ?: "");
		return -EINVAL;
	}
	kobject_get_ownership(kobj, &uid, &gid);
	if (grp->name) {
		if (update) {
			kn = kernfs_find_and_get(kobj->sd, grp->name);
			if (!kn) {
				pr_warn("Can't update unknown attr grp name: %s/%s\n",
					kobj->name, grp->name);
				return -EINVAL;
			}
		} else {
			kn = kernfs_create_dir_ns(kobj->sd, grp->name,
						  S_IRWXU | S_IRUGO | S_IXUGO,
						  uid, gid, kobj, NULL);
			if (IS_ERR(kn)) {
				if (PTR_ERR(kn) == -EEXIST)
					sysfs_warn_dup(kobj->sd, grp->name);
				return PTR_ERR(kn);
			}
		}
	} else
		kn = kobj->sd;
	kernfs_get(kn);
	error = create_files(kn, kobj, uid, gid, grp, update);
	if (error) {
		if (grp->name)
			kernfs_remove(kn);
	}
	kernfs_put(kn);

	if (grp->name && update)
		kernfs_put(kn);

	return error;
}

/**
 * sysfs_create_group - given a directory kobject, create an attribute group
 * @kobj:	The kobject to create the group on
 * @grp:	The attribute group to create
 *
 * This function creates a group for the first time.  It will explicitly
 * warn and error if any of the attribute files being created already exist.
 *
 * Returns 0 on success or error code on failure.
 */
int sysfs_create_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	return internal_create_group(kobj, 0, grp);
}
EXPORT_SYMBOL_GPL(sysfs_create_group);

static int internal_create_groups(struct kobject *kobj, int update,
				  const struct attribute_group **groups)
{
	int error = 0;
	int i;

	if (!groups)
		return 0;

	for (i = 0; groups[i]; i++) {
		error = internal_create_group(kobj, update, groups[i]);
		if (error) {
			while (--i >= 0)
				sysfs_remove_group(kobj, groups[i]);
			break;
		}
	}
	return error;
}

/**
 * sysfs_create_groups - given a directory kobject, create a bunch of attribute groups
 * @kobj:	The kobject to create the group on
 * @groups:	The attribute groups to create, NULL terminated
 *
 * This function creates a bunch of attribute groups.  If an error occurs when
 * creating a group, all previously created groups will be removed, unwinding
 * everything back to the original state when this function was called.
 * It will explicitly warn and error if any of the attribute files being
 * created already exist.
 *
 * Returns 0 on success or error code from sysfs_create_group on failure.
 */
int sysfs_create_groups(struct kobject *kobj,
			const struct attribute_group **groups)
{
	return internal_create_groups(kobj, 0, groups);
}
EXPORT_SYMBOL_GPL(sysfs_create_groups);

/**
 * sysfs_update_groups - given a directory kobject, create a bunch of attribute groups
 * @kobj:	The kobject to update the group on
 * @groups:	The attribute groups to update, NULL terminated
 *
 * This function update a bunch of attribute groups.  If an error occurs when
 * updating a group, all previously updated groups will be removed together
 * with already existing (not updated) attributes.
 *
 * Returns 0 on success or error code from sysfs_update_group on failure.
 */
int sysfs_update_groups(struct kobject *kobj,
			const struct attribute_group **groups)
{
	return internal_create_groups(kobj, 1, groups);
}
EXPORT_SYMBOL_GPL(sysfs_update_groups);

/**
 * sysfs_update_group - given a directory kobject, update an attribute group
 * @kobj:	The kobject to update the group on
 * @grp:	The attribute group to update
 *
 * This function updates an attribute group.  Unlike
 * sysfs_create_group(), it will explicitly not warn or error if any
 * of the attribute files being created already exist.  Furthermore,
 * if the visibility of the files has changed through the is_visible()
 * callback, it will update the permissions and add or remove the
 * relevant files. Changing a group's name (subdirectory name under
 * kobj's directory in sysfs) is not allowed.
 *
 * The primary use for this function is to call it after making a change
 * that affects group visibility.
 *
 * Returns 0 on success or error code on failure.
 */
int sysfs_update_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	return internal_create_group(kobj, 1, grp);
}
EXPORT_SYMBOL_GPL(sysfs_update_group);

/**
 * sysfs_remove_group: remove a group from a kobject
 * @kobj:	kobject to remove the group from
 * @grp:	group to remove
 *
 * This function removes a group of attributes from a kobject.  The attributes
 * previously have to have been created for this group, otherwise it will fail.
 */
void sysfs_remove_group(struct kobject *kobj,
			const struct attribute_group *grp)
{
	struct kernfs_node *parent = kobj->sd;
	struct kernfs_node *kn;

	if (grp->name) {
		kn = kernfs_find_and_get(parent, grp->name);
		if (!kn) {
			WARN(!kn, KERN_WARNING
			     "sysfs group '%s' not found for kobject '%s'\n",
			     grp->name, kobject_name(kobj));
			return;
		}
	} else {
		kn = parent;
		kernfs_get(kn);
	}

	remove_files(kn, grp);
	if (grp->name)
		kernfs_remove(kn);

	kernfs_put(kn);
}
EXPORT_SYMBOL_GPL(sysfs_remove_group);

/**
 * sysfs_remove_groups - remove a list of groups
 *
 * @kobj:	The kobject for the groups to be removed from
 * @groups:	NULL terminated list of groups to be removed
 *
 * If groups is not NULL, remove the specified groups from the kobject.
 */
void sysfs_remove_groups(struct kobject *kobj,
			 const struct attribute_group **groups)
{
	int i;

	if (!groups)
		return;
	for (i = 0; groups[i]; i++)
		sysfs_remove_group(kobj, groups[i]);
}
EXPORT_SYMBOL_GPL(sysfs_remove_groups);

/**
 * sysfs_merge_group - merge files into a pre-existing attribute group.
 * @kobj:	The kobject containing the group.
 * @grp:	The files to create and the attribute group they belong to.
 *
 * This function returns an error if the group doesn't exist or any of the
 * files already exist in that group, in which case none of the new files
 * are created.
 */
int sysfs_merge_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	struct kernfs_node *parent;
	kuid_t uid;
	kgid_t gid;
	int error = 0;
	struct attribute *const *attr;
	int i;

	parent = kernfs_find_and_get(kobj->sd, grp->name);
	if (!parent)
		return -ENOENT;

	kobject_get_ownership(kobj, &uid, &gid);

	for ((i = 0, attr = grp->attrs); *attr && !error; (++i, ++attr))
		error = sysfs_add_file_mode_ns(parent, *attr, false,
					       (*attr)->mode, uid, gid, NULL);
	if (error) {
		while (--i >= 0)
			kernfs_remove_by_name(parent, (*--attr)->name);
	}
	kernfs_put(parent);

	return error;
}
EXPORT_SYMBOL_GPL(sysfs_merge_group);

/**
 * sysfs_unmerge_group - remove files from a pre-existing attribute group.
 * @kobj:	The kobject containing the group.
 * @grp:	The files to remove and the attribute group they belong to.
 */
void sysfs_unmerge_group(struct kobject *kobj,
		       const struct attribute_group *grp)
{
	struct kernfs_node *parent;
	struct attribute *const *attr;

	parent = kernfs_find_and_get(kobj->sd, grp->name);
	if (parent) {
		for (attr = grp->attrs; *attr; ++attr)
			kernfs_remove_by_name(parent, (*attr)->name);
		kernfs_put(parent);
	}
}
EXPORT_SYMBOL_GPL(sysfs_unmerge_group);

/**
 * sysfs_add_link_to_group - add a symlink to an attribute group.
 * @kobj:	The kobject containing the group.
 * @group_name:	The name of the group.
 * @target:	The target kobject of the symlink to create.
 * @link_name:	The name of the symlink to create.
 */
int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
			    struct kobject *target, const char *link_name)
{
	struct kernfs_node *parent;
	int error = 0;

	parent = kernfs_find_and_get(kobj->sd, group_name);
	if (!parent)
		return -ENOENT;

	error = sysfs_create_link_sd(parent, target, link_name);
	kernfs_put(parent);

	return error;
}
EXPORT_SYMBOL_GPL(sysfs_add_link_to_group);

/**
 * sysfs_remove_link_from_group - remove a symlink from an attribute group.
 * @kobj:	The kobject containing the group.
 * @group_name:	The name of the group.
 * @link_name:	The name of the symlink to remove.
 */
void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
				  const char *link_name)
{
	struct kernfs_node *parent;

	parent = kernfs_find_and_get(kobj->sd, group_name);
	if (parent) {
		kernfs_remove_by_name(parent, link_name);
		kernfs_put(parent);
	}
}
EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);

/**
 * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
 * to a group or an attribute
 * @kobj:		The kobject containing the group.
 * @target_kobj:	The target kobject.
 * @target_name:	The name of the target group or attribute.
 */
int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
				      struct kobject *target_kobj,
				      const char *target_name)
{
	struct kernfs_node *target;
	struct kernfs_node *entry;
	struct kernfs_node *link;

	/*
	 * We don't own @target_kobj and it may be removed at any time.
	 * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
	 * for details.
	 */
	spin_lock(&sysfs_symlink_target_lock);
	target = target_kobj->sd;
	if (target)
		kernfs_get(target);
	spin_unlock(&sysfs_symlink_target_lock);
	if (!target)
		return -ENOENT;

	entry = kernfs_find_and_get(target_kobj->sd, target_name);
	if (!entry) {
		kernfs_put(target);
		return -ENOENT;
	}

	link = kernfs_create_link(kobj->sd, target_name, entry);
	if (PTR_ERR(link) == -EEXIST)
		sysfs_warn_dup(kobj->sd, target_name);

	kernfs_put(entry);
	kernfs_put(target);
	return PTR_ERR_OR_ZERO(link);
}
EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);

static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn,
					  const struct attribute_group *grp,
					  struct iattr *newattrs)
{
	struct kernfs_node *kn;
	int error;

	if (grp->attrs) {
		struct attribute *const *attr;

		for (attr = grp->attrs; *attr; attr++) {
			kn = kernfs_find_and_get(grp_kn, (*attr)->name);
			if (!kn)
				return -ENOENT;

			error = kernfs_setattr(kn, newattrs);
			kernfs_put(kn);
			if (error)
				return error;
		}
	}

	if (grp->bin_attrs) {
		struct bin_attribute *const *bin_attr;

		for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
			kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name);
			if (!kn)
				return -ENOENT;

			error = kernfs_setattr(kn, newattrs);
			kernfs_put(kn);
			if (error)
				return error;
		}
	}

	return 0;
}

/**
 * sysfs_group_change_owner - change owner of an attribute group.
 * @kobj:	The kobject containing the group.
 * @grp:	The attribute group.
 * @kuid:	new owner's kuid
 * @kgid:	new owner's kgid
 *
 * Returns 0 on success or error code on failure.
 */
int sysfs_group_change_owner(struct kobject *kobj,
			     const struct attribute_group *grp, kuid_t kuid,
			     kgid_t kgid)
{
	struct kernfs_node *grp_kn;
	int error;
	struct iattr newattrs = {
		.ia_valid = ATTR_UID | ATTR_GID,
		.ia_uid = kuid,
		.ia_gid = kgid,
	};

	if (!kobj->state_in_sysfs)
		return -EINVAL;

	if (grp->name) {
		grp_kn = kernfs_find_and_get(kobj->sd, grp->name);
	} else {
		kernfs_get(kobj->sd);
		grp_kn = kobj->sd;
	}
	if (!grp_kn)
		return -ENOENT;

	error = kernfs_setattr(grp_kn, &newattrs);
	if (!error)
		error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs);

	kernfs_put(grp_kn);

	return error;
}
EXPORT_SYMBOL_GPL(sysfs_group_change_owner);

/**
 * sysfs_groups_change_owner - change owner of a set of attribute groups.
 * @kobj:	The kobject containing the groups.
 * @groups:	The attribute groups.
 * @kuid:	new owner's kuid
 * @kgid:	new owner's kgid
 *
 * Returns 0 on success or error code on failure.
 */
int sysfs_groups_change_owner(struct kobject *kobj,
			      const struct attribute_group **groups,
			      kuid_t kuid, kgid_t kgid)
{
	int error = 0, i;

	if (!kobj->state_in_sysfs)
		return -EINVAL;

	if (!groups)
		return 0;

	for (i = 0; groups[i]; i++) {
		error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid);
		if (error)
			break;
	}

	return error;
}
EXPORT_SYMBOL_GPL(sysfs_groups_change_owner);