summaryrefslogtreecommitdiffstats
path: root/u-boot/fs/ubifs/key.h
blob: efb3430a2581c4b723cafc6f846ed7b5841ed933 (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
/*
 * This file is part of UBIFS.
 *
 * Copyright (C) 2006-2008 Nokia Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
 *
 * Authors: Artem Bityutskiy (Битюцкий Артём)
 *          Adrian Hunter
 */

/*
 * This header contains various key-related definitions and helper function.
 * UBIFS allows several key schemes, so we access key fields only via these
 * helpers. At the moment only one key scheme is supported.
 *
 * Simple key scheme
 * ~~~~~~~~~~~~~~~~~
 *
 * Keys are 64-bits long. First 32-bits are inode number (parent inode number
 * in case of direntry key). Next 3 bits are node type. The last 29 bits are
 * 4KiB offset in case of inode node, and direntry hash in case of a direntry
 * node. We use "r5" hash borrowed from reiserfs.
 */

#ifndef __UBIFS_KEY_H__
#define __UBIFS_KEY_H__

/**
 * key_mask_hash - mask a valid hash value.
 * @val: value to be masked
 *
 * We use hash values as offset in directories, so values %0 and %1 are
 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
 * function makes sure the reserved values are not used.
 */
static inline uint32_t key_mask_hash(uint32_t hash)
{
	hash &= UBIFS_S_KEY_HASH_MASK;
	if (unlikely(hash <= 2))
		hash += 3;
	return hash;
}

/**
 * key_r5_hash - R5 hash function (borrowed from reiserfs).
 * @s: direntry name
 * @len: name length
 */
static inline uint32_t key_r5_hash(const char *s, int len)
{
	uint32_t a = 0;
	const signed char *str = (const signed char *)s;

	while (*str) {
		a += *str << 4;
		a += *str >> 4;
		a *= 11;
		str++;
	}

	return key_mask_hash(a);
}

/**
 * key_test_hash - testing hash function.
 * @str: direntry name
 * @len: name length
 */
static inline uint32_t key_test_hash(const char *str, int len)
{
	uint32_t a = 0;

	len = min_t(uint32_t, len, 4);
	memcpy(&a, str, len);
	return key_mask_hash(a);
}

/**
 * ino_key_init - initialize inode key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: inode number
 */
static inline void ino_key_init(const struct ubifs_info *c,
				union ubifs_key *key, ino_t inum)
{
	key->u32[0] = inum;
	key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
}

/**
 * ino_key_init_flash - initialize on-flash inode key.
 * @c: UBIFS file-system description object
 * @k: key to initialize
 * @inum: inode number
 */
static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
				      ino_t inum)
{
	union ubifs_key *key = k;

	key->j32[0] = cpu_to_le32(inum);
	key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}

/**
 * lowest_ino_key - get the lowest possible inode key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: inode number
 */
static inline void lowest_ino_key(const struct ubifs_info *c,
				union ubifs_key *key, ino_t inum)
{
	key->u32[0] = inum;
	key->u32[1] = 0;
}

/**
 * highest_ino_key - get the highest possible inode key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: inode number
 */
static inline void highest_ino_key(const struct ubifs_info *c,
				union ubifs_key *key, ino_t inum)
{
	key->u32[0] = inum;
	key->u32[1] = 0xffffffff;
}

/**
 * dent_key_init - initialize directory entry key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: parent inode number
 * @nm: direntry name and length
 */
static inline void dent_key_init(const struct ubifs_info *c,
				 union ubifs_key *key, ino_t inum,
				 const struct qstr *nm)
{
	uint32_t hash = c->key_hash(nm->name, nm->len);

	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
	key->u32[0] = inum;
	key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
}

/**
 * dent_key_init_hash - initialize directory entry key without re-calculating
 *                      hash function.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: parent inode number
 * @hash: direntry name hash
 */
static inline void dent_key_init_hash(const struct ubifs_info *c,
				      union ubifs_key *key, ino_t inum,
				      uint32_t hash)
{
	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
	key->u32[0] = inum;
	key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
}

/**
 * dent_key_init_flash - initialize on-flash directory entry key.
 * @c: UBIFS file-system description object
 * @k: key to initialize
 * @inum: parent inode number
 * @nm: direntry name and length
 */
static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
				       ino_t inum, const struct qstr *nm)
{
	union ubifs_key *key = k;
	uint32_t hash = c->key_hash(nm->name, nm->len);

	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
	key->j32[0] = cpu_to_le32(inum);
	key->j32[1] = cpu_to_le32(hash |
				  (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}

/**
 * lowest_dent_key - get the lowest possible directory entry key.
 * @c: UBIFS file-system description object
 * @key: where to store the lowest key
 * @inum: parent inode number
 */
static inline void lowest_dent_key(const struct ubifs_info *c,
				   union ubifs_key *key, ino_t inum)
{
	key->u32[0] = inum;
	key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
}

/**
 * xent_key_init - initialize extended attribute entry key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: host inode number
 * @nm: extended attribute entry name and length
 */
static inline void xent_key_init(const struct ubifs_info *c,
				 union ubifs_key *key, ino_t inum,
				 const struct qstr *nm)
{
	uint32_t hash = c->key_hash(nm->name, nm->len);

	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
	key->u32[0] = inum;
	key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
}

/**
 * xent_key_init_hash - initialize extended attribute entry key without
 *                      re-calculating hash function.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: host inode number
 * @hash: extended attribute entry name hash
 */
static inline void xent_key_init_hash(const struct ubifs_info *c,
				      union ubifs_key *key, ino_t inum,
				      uint32_t hash)
{
	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
	key->u32[0] = inum;
	key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
}

/**
 * xent_key_init_flash - initialize on-flash extended attribute entry key.
 * @c: UBIFS file-system description object
 * @k: key to initialize
 * @inum: host inode number
 * @nm: extended attribute entry name and length
 */
static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
				       ino_t inum, const struct qstr *nm)
{
	union ubifs_key *key = k;
	uint32_t hash = c->key_hash(nm->name, nm->len);

	ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
	key->j32[0] = cpu_to_le32(inum);
	key->j32[1] = cpu_to_le32(hash |
				  (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}

/**
 * lowest_xent_key - get the lowest possible extended attribute entry key.
 * @c: UBIFS file-system description object
 * @key: where to store the lowest key
 * @inum: host inode number
 */
static inline void lowest_xent_key(const struct ubifs_info *c,
				   union ubifs_key *key, ino_t inum)
{
	key->u32[0] = inum;
	key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
}

/**
 * data_key_init - initialize data key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: inode number
 * @block: block number
 */
static inline void data_key_init(const struct ubifs_info *c,
				 union ubifs_key *key, ino_t inum,
				 unsigned int block)
{
	ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
	key->u32[0] = inum;
	key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
}

/**
 * data_key_init_flash - initialize on-flash data key.
 * @c: UBIFS file-system description object
 * @k: key to initialize
 * @inum: inode number
 * @block: block number
 */
static inline void data_key_init_flash(const struct ubifs_info *c, void *k,
				       ino_t inum, unsigned int block)
{
	union ubifs_key *key = k;

	ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
	key->j32[0] = cpu_to_le32(inum);
	key->j32[1] = cpu_to_le32(block |
				  (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS));
	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}

/**
 * trun_key_init - initialize truncation node key.
 * @c: UBIFS file-system description object
 * @key: key to initialize
 * @inum: inode number
 *
 * Note, UBIFS does not have truncation keys on the media and this function is
 * only used for purposes of replay.
 */
static inline void trun_key_init(const struct ubifs_info *c,
				 union ubifs_key *key, ino_t inum)
{
	key->u32[0] = inum;
	key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
}

/**
 * key_type - get key type.
 * @c: UBIFS file-system description object
 * @key: key to get type of
 */
static inline int key_type(const struct ubifs_info *c,
			   const union ubifs_key *key)
{
	return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
}

/**
 * key_type_flash - get type of a on-flash formatted key.
 * @c: UBIFS file-system description object
 * @k: key to get type of
 */
static inline int key_type_flash(const struct ubifs_info *c, const void *k)
{
	const union ubifs_key *key = k;

	return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
}

/**
 * key_inum - fetch inode number from key.
 * @c: UBIFS file-system description object
 * @k: key to fetch inode number from
 */
static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
{
	const union ubifs_key *key = k;

	return key->u32[0];
}

/**
 * key_inum_flash - fetch inode number from an on-flash formatted key.
 * @c: UBIFS file-system description object
 * @k: key to fetch inode number from
 */
static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
{
	const union ubifs_key *key = k;

	return le32_to_cpu(key->j32[0]);
}

/**
 * key_hash - get directory entry hash.
 * @c: UBIFS file-system description object
 * @key: the key to get hash from
 */
static inline int key_hash(const struct ubifs_info *c,
			   const union ubifs_key *key)
{
	return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
}

/**
 * key_hash_flash - get directory entry hash from an on-flash formatted key.
 * @c: UBIFS file-system description object
 * @k: the key to get hash from
 */
static inline int key_hash_flash(const struct ubifs_info *c, const void *k)
{
	const union ubifs_key *key = k;

	return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
}

/**
 * key_block - get data block number.
 * @c: UBIFS file-system description object
 * @key: the key to get the block number from
 */
static inline unsigned int key_block(const struct ubifs_info *c,
				     const union ubifs_key *key)
{
	return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
}

/**
 * key_block_flash - get data block number from an on-flash formatted key.
 * @c: UBIFS file-system description object
 * @k: the key to get the block number from
 */
static inline unsigned int key_block_flash(const struct ubifs_info *c,
					   const void *k)
{
	const union ubifs_key *key = k;

	return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
}

/**
 * key_read - transform a key to in-memory format.
 * @c: UBIFS file-system description object
 * @from: the key to transform
 * @to: the key to store the result
 */
static inline void key_read(const struct ubifs_info *c, const void *from,
			    union ubifs_key *to)
{
	const union ubifs_key *f = from;

	to->u32[0] = le32_to_cpu(f->j32[0]);
	to->u32[1] = le32_to_cpu(f->j32[1]);
}

/**
 * key_write - transform a key from in-memory format.
 * @c: UBIFS file-system description object
 * @from: the key to transform
 * @to: the key to store the result
 */
static inline void key_write(const struct ubifs_info *c,
			     const union ubifs_key *from, void *to)
{
	union ubifs_key *t = to;

	t->j32[0] = cpu_to_le32(from->u32[0]);
	t->j32[1] = cpu_to_le32(from->u32[1]);
	memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
}

/**
 * key_write_idx - transform a key from in-memory format for the index.
 * @c: UBIFS file-system description object
 * @from: the key to transform
 * @to: the key to store the result
 */
static inline void key_write_idx(const struct ubifs_info *c,
				 const union ubifs_key *from, void *to)
{
	union ubifs_key *t = to;

	t->j32[0] = cpu_to_le32(from->u32[0]);
	t->j32[1] = cpu_to_le32(from->u32[1]);
}

/**
 * key_copy - copy a key.
 * @c: UBIFS file-system description object
 * @from: the key to copy from
 * @to: the key to copy to
 */
static inline void key_copy(const struct ubifs_info *c,
			    const union ubifs_key *from, union ubifs_key *to)
{
	to->u64[0] = from->u64[0];
}

/**
 * keys_cmp - compare keys.
 * @c: UBIFS file-system description object
 * @key1: the first key to compare
 * @key2: the second key to compare
 *
 * This function compares 2 keys and returns %-1 if @key1 is less than
 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
 */
static inline int keys_cmp(const struct ubifs_info *c,
			   const union ubifs_key *key1,
			   const union ubifs_key *key2)
{
	if (key1->u32[0] < key2->u32[0])
		return -1;
	if (key1->u32[0] > key2->u32[0])
		return 1;
	if (key1->u32[1] < key2->u32[1])
		return -1;
	if (key1->u32[1] > key2->u32[1])
		return 1;

	return 0;
}

/**
 * keys_eq - determine if keys are equivalent.
 * @c: UBIFS file-system description object
 * @key1: the first key to compare
 * @key2: the second key to compare
 *
 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
 * %0 if not.
 */
static inline int keys_eq(const struct ubifs_info *c,
			  const union ubifs_key *key1,
			  const union ubifs_key *key2)
{
	if (key1->u32[0] != key2->u32[0])
		return 0;
	if (key1->u32[1] != key2->u32[1])
		return 0;
	return 1;
}

/**
 * is_hash_key - is a key vulnerable to hash collisions.
 * @c: UBIFS file-system description object
 * @key: key
 *
 * This function returns %1 if @key is a hashed key or %0 otherwise.
 */
static inline int is_hash_key(const struct ubifs_info *c,
			      const union ubifs_key *key)
{
	int type = key_type(c, key);

	return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
}

/**
 * key_max_inode_size - get maximum file size allowed by current key format.
 * @c: UBIFS file-system description object
 */
static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
{
	switch (c->key_fmt) {
	case UBIFS_SIMPLE_KEY_FMT:
		return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
	default:
		return 0;
	}
}
#endif /* !__UBIFS_KEY_H__ */