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1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
21 */
22
23/*
24 * This header contains various key-related definitions and helper function.
25 * UBIFS allows several key schemes, so we access key fields only via these
26 * helpers. At the moment only one key scheme is supported.
27 *
28 * Simple key scheme
29 * ~~~~~~~~~~~~~~~~~
30 *
31 * Keys are 64-bits long. First 32-bits are inode number (parent inode number
32 * in case of direntry key). Next 3 bits are node type. The last 29 bits are
33 * 4KiB offset in case of inode node, and direntry hash in case of a direntry
34 * node. We use "r5" hash borrowed from reiserfs.
35 */
36
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37/*
38 * Lot's of the key helpers require a struct ubifs_info *c as the first parameter.
39 * But we are not using it at all currently. That's designed for future extensions of
40 * different c->key_format. But right now, there is only one key type, UBIFS_SIMPLE_KEY_FMT.
41 */
42
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43#ifndef __UBIFS_KEY_H__
44#define __UBIFS_KEY_H__
45
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46/**
47 * key_mask_hash - mask a valid hash value.
48 * @val: value to be masked
49 *
50 * We use hash values as offset in directories, so values %0 and %1 are
51 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
52 * function makes sure the reserved values are not used.
53 */
54static inline uint32_t key_mask_hash(uint32_t hash)
55{
56 hash &= UBIFS_S_KEY_HASH_MASK;
57 if (unlikely(hash <= 2))
58 hash += 3;
59 return hash;
60}
61
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62/**
63 * key_r5_hash - R5 hash function (borrowed from reiserfs).
64 * @s: direntry name
65 * @len: name length
66 */
67static inline uint32_t key_r5_hash(const char *s, int len)
68{
69 uint32_t a = 0;
70 const signed char *str = (const signed char *)s;
71
b9bc8c7b 72 while (len--) {
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73 a += *str << 4;
74 a += *str >> 4;
75 a *= 11;
76 str++;
77 }
78
5dd7cbc0 79 return key_mask_hash(a);
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80}
81
82/**
83 * key_test_hash - testing hash function.
84 * @str: direntry name
85 * @len: name length
86 */
87static inline uint32_t key_test_hash(const char *str, int len)
88{
89 uint32_t a = 0;
90
91 len = min_t(uint32_t, len, 4);
92 memcpy(&a, str, len);
5dd7cbc0 93 return key_mask_hash(a);
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94}
95
96/**
97 * ino_key_init - initialize inode key.
98 * @c: UBIFS file-system description object
99 * @key: key to initialize
100 * @inum: inode number
101 */
102static inline void ino_key_init(const struct ubifs_info *c,
103 union ubifs_key *key, ino_t inum)
104{
105 key->u32[0] = inum;
106 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
107}
108
109/**
110 * ino_key_init_flash - initialize on-flash inode key.
111 * @c: UBIFS file-system description object
112 * @k: key to initialize
113 * @inum: inode number
114 */
115static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
116 ino_t inum)
117{
118 union ubifs_key *key = k;
119
120 key->j32[0] = cpu_to_le32(inum);
121 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
122 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
123}
124
125/**
126 * lowest_ino_key - get the lowest possible inode key.
127 * @c: UBIFS file-system description object
128 * @key: key to initialize
129 * @inum: inode number
130 */
131static inline void lowest_ino_key(const struct ubifs_info *c,
132 union ubifs_key *key, ino_t inum)
133{
134 key->u32[0] = inum;
135 key->u32[1] = 0;
136}
137
138/**
139 * highest_ino_key - get the highest possible inode key.
140 * @c: UBIFS file-system description object
141 * @key: key to initialize
142 * @inum: inode number
143 */
144static inline void highest_ino_key(const struct ubifs_info *c,
145 union ubifs_key *key, ino_t inum)
146{
147 key->u32[0] = inum;
148 key->u32[1] = 0xffffffff;
149}
150
151/**
152 * dent_key_init - initialize directory entry key.
153 * @c: UBIFS file-system description object
154 * @key: key to initialize
155 * @inum: parent inode number
f4f61d2c 156 * @nm: direntry name and length. Not a string when encrypted!
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157 */
158static inline void dent_key_init(const struct ubifs_info *c,
159 union ubifs_key *key, ino_t inum,
f4f61d2c 160 const struct fscrypt_name *nm)
1e51764a 161{
f4f61d2c 162 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
1e51764a 163
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164 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
165 ubifs_assert(c, !nm->hash && !nm->minor_hash);
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166 key->u32[0] = inum;
167 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
168}
169
170/**
171 * dent_key_init_hash - initialize directory entry key without re-calculating
172 * hash function.
173 * @c: UBIFS file-system description object
174 * @key: key to initialize
175 * @inum: parent inode number
176 * @hash: direntry name hash
177 */
178static inline void dent_key_init_hash(const struct ubifs_info *c,
179 union ubifs_key *key, ino_t inum,
180 uint32_t hash)
181{
6eb61d58 182 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
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183 key->u32[0] = inum;
184 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
185}
186
187/**
188 * dent_key_init_flash - initialize on-flash directory entry key.
189 * @c: UBIFS file-system description object
190 * @k: key to initialize
191 * @inum: parent inode number
192 * @nm: direntry name and length
193 */
194static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
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195 ino_t inum,
196 const struct fscrypt_name *nm)
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197{
198 union ubifs_key *key = k;
f4f61d2c 199 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
1e51764a 200
6eb61d58 201 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
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202 key->j32[0] = cpu_to_le32(inum);
203 key->j32[1] = cpu_to_le32(hash |
204 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
205 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
206}
207
208/**
209 * lowest_dent_key - get the lowest possible directory entry key.
210 * @c: UBIFS file-system description object
211 * @key: where to store the lowest key
212 * @inum: parent inode number
213 */
214static inline void lowest_dent_key(const struct ubifs_info *c,
215 union ubifs_key *key, ino_t inum)
216{
217 key->u32[0] = inum;
218 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
219}
220
221/**
222 * xent_key_init - initialize extended attribute entry key.
223 * @c: UBIFS file-system description object
224 * @key: key to initialize
225 * @inum: host inode number
226 * @nm: extended attribute entry name and length
227 */
228static inline void xent_key_init(const struct ubifs_info *c,
229 union ubifs_key *key, ino_t inum,
f4f61d2c 230 const struct fscrypt_name *nm)
1e51764a 231{
f4f61d2c 232 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
1e51764a 233
6eb61d58 234 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
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235 key->u32[0] = inum;
236 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
237}
238
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239/**
240 * xent_key_init_flash - initialize on-flash extended attribute entry key.
241 * @c: UBIFS file-system description object
242 * @k: key to initialize
243 * @inum: host inode number
244 * @nm: extended attribute entry name and length
245 */
246static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
f4f61d2c 247 ino_t inum, const struct fscrypt_name *nm)
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248{
249 union ubifs_key *key = k;
f4f61d2c 250 uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
1e51764a 251
6eb61d58 252 ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
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253 key->j32[0] = cpu_to_le32(inum);
254 key->j32[1] = cpu_to_le32(hash |
255 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
256 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
257}
258
259/**
260 * lowest_xent_key - get the lowest possible extended attribute entry key.
261 * @c: UBIFS file-system description object
262 * @key: where to store the lowest key
263 * @inum: host inode number
264 */
265static inline void lowest_xent_key(const struct ubifs_info *c,
266 union ubifs_key *key, ino_t inum)
267{
268 key->u32[0] = inum;
269 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
270}
271
272/**
273 * data_key_init - initialize data key.
274 * @c: UBIFS file-system description object
275 * @key: key to initialize
276 * @inum: inode number
277 * @block: block number
278 */
279static inline void data_key_init(const struct ubifs_info *c,
280 union ubifs_key *key, ino_t inum,
281 unsigned int block)
282{
6eb61d58 283 ubifs_assert(c, !(block & ~UBIFS_S_KEY_BLOCK_MASK));
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284 key->u32[0] = inum;
285 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
286}
287
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288/**
289 * highest_data_key - get the highest possible data key for an inode.
290 * @c: UBIFS file-system description object
291 * @key: key to initialize
292 * @inum: inode number
293 */
294static inline void highest_data_key(const struct ubifs_info *c,
295 union ubifs_key *key, ino_t inum)
296{
297 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
298}
299
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300/**
301 * trun_key_init - initialize truncation node key.
302 * @c: UBIFS file-system description object
303 * @key: key to initialize
304 * @inum: inode number
305 *
306 * Note, UBIFS does not have truncation keys on the media and this function is
307 * only used for purposes of replay.
308 */
309static inline void trun_key_init(const struct ubifs_info *c,
310 union ubifs_key *key, ino_t inum)
311{
312 key->u32[0] = inum;
313 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
314}
315
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316/**
317 * invalid_key_init - initialize invalid node key.
318 * @c: UBIFS file-system description object
319 * @key: key to initialize
320 *
321 * This is a helper function which marks a @key object as invalid.
322 */
323static inline void invalid_key_init(const struct ubifs_info *c,
324 union ubifs_key *key)
325{
326 key->u32[0] = 0xDEADBEAF;
327 key->u32[1] = UBIFS_INVALID_KEY;
328}
329
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330/**
331 * key_type - get key type.
332 * @c: UBIFS file-system description object
333 * @key: key to get type of
334 */
335static inline int key_type(const struct ubifs_info *c,
336 const union ubifs_key *key)
337{
338 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
339}
340
341/**
342 * key_type_flash - get type of a on-flash formatted key.
343 * @c: UBIFS file-system description object
344 * @k: key to get type of
345 */
346static inline int key_type_flash(const struct ubifs_info *c, const void *k)
347{
348 const union ubifs_key *key = k;
349
0ecb9529 350 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
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351}
352
353/**
354 * key_inum - fetch inode number from key.
355 * @c: UBIFS file-system description object
356 * @k: key to fetch inode number from
357 */
358static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
359{
360 const union ubifs_key *key = k;
361
362 return key->u32[0];
363}
364
365/**
366 * key_inum_flash - fetch inode number from an on-flash formatted key.
367 * @c: UBIFS file-system description object
368 * @k: key to fetch inode number from
369 */
370static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
371{
372 const union ubifs_key *key = k;
373
374 return le32_to_cpu(key->j32[0]);
375}
376
377/**
378 * key_hash - get directory entry hash.
379 * @c: UBIFS file-system description object
380 * @key: the key to get hash from
381 */
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382static inline uint32_t key_hash(const struct ubifs_info *c,
383 const union ubifs_key *key)
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384{
385 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
386}
387
388/**
389 * key_hash_flash - get directory entry hash from an on-flash formatted key.
390 * @c: UBIFS file-system description object
391 * @k: the key to get hash from
392 */
cb4f952d 393static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
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394{
395 const union ubifs_key *key = k;
396
397 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
398}
399
400/**
401 * key_block - get data block number.
402 * @c: UBIFS file-system description object
403 * @key: the key to get the block number from
404 */
405static inline unsigned int key_block(const struct ubifs_info *c,
406 const union ubifs_key *key)
407{
408 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
409}
410
411/**
412 * key_block_flash - get data block number from an on-flash formatted key.
413 * @c: UBIFS file-system description object
414 * @k: the key to get the block number from
415 */
416static inline unsigned int key_block_flash(const struct ubifs_info *c,
417 const void *k)
418{
419 const union ubifs_key *key = k;
420
0ecb9529 421 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
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422}
423
424/**
425 * key_read - transform a key to in-memory format.
426 * @c: UBIFS file-system description object
427 * @from: the key to transform
428 * @to: the key to store the result
429 */
430static inline void key_read(const struct ubifs_info *c, const void *from,
431 union ubifs_key *to)
432{
433 const union ubifs_key *f = from;
434
435 to->u32[0] = le32_to_cpu(f->j32[0]);
436 to->u32[1] = le32_to_cpu(f->j32[1]);
437}
438
439/**
440 * key_write - transform a key from in-memory format.
441 * @c: UBIFS file-system description object
442 * @from: the key to transform
443 * @to: the key to store the result
444 */
445static inline void key_write(const struct ubifs_info *c,
446 const union ubifs_key *from, void *to)
447{
448 union ubifs_key *t = to;
449
450 t->j32[0] = cpu_to_le32(from->u32[0]);
451 t->j32[1] = cpu_to_le32(from->u32[1]);
452 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
453}
454
455/**
456 * key_write_idx - transform a key from in-memory format for the index.
457 * @c: UBIFS file-system description object
458 * @from: the key to transform
459 * @to: the key to store the result
460 */
461static inline void key_write_idx(const struct ubifs_info *c,
462 const union ubifs_key *from, void *to)
463{
464 union ubifs_key *t = to;
465
466 t->j32[0] = cpu_to_le32(from->u32[0]);
467 t->j32[1] = cpu_to_le32(from->u32[1]);
468}
469
470/**
471 * key_copy - copy a key.
472 * @c: UBIFS file-system description object
473 * @from: the key to copy from
474 * @to: the key to copy to
475 */
476static inline void key_copy(const struct ubifs_info *c,
477 const union ubifs_key *from, union ubifs_key *to)
478{
479 to->u64[0] = from->u64[0];
480}
481
482/**
483 * keys_cmp - compare keys.
484 * @c: UBIFS file-system description object
485 * @key1: the first key to compare
486 * @key2: the second key to compare
487 *
488 * This function compares 2 keys and returns %-1 if @key1 is less than
4793e7c5 489 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
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490 */
491static inline int keys_cmp(const struct ubifs_info *c,
492 const union ubifs_key *key1,
493 const union ubifs_key *key2)
494{
495 if (key1->u32[0] < key2->u32[0])
496 return -1;
497 if (key1->u32[0] > key2->u32[0])
498 return 1;
499 if (key1->u32[1] < key2->u32[1])
500 return -1;
501 if (key1->u32[1] > key2->u32[1])
502 return 1;
503
504 return 0;
505}
506
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507/**
508 * keys_eq - determine if keys are equivalent.
509 * @c: UBIFS file-system description object
510 * @key1: the first key to compare
511 * @key2: the second key to compare
512 *
513 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
514 * %0 if not.
515 */
516static inline int keys_eq(const struct ubifs_info *c,
517 const union ubifs_key *key1,
518 const union ubifs_key *key2)
519{
520 if (key1->u32[0] != key2->u32[0])
521 return 0;
522 if (key1->u32[1] != key2->u32[1])
523 return 0;
524 return 1;
525}
526
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527/**
528 * is_hash_key - is a key vulnerable to hash collisions.
529 * @c: UBIFS file-system description object
530 * @key: key
531 *
532 * This function returns %1 if @key is a hashed key or %0 otherwise.
533 */
534static inline int is_hash_key(const struct ubifs_info *c,
535 const union ubifs_key *key)
536{
537 int type = key_type(c, key);
538
539 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
540}
541
542/**
543 * key_max_inode_size - get maximum file size allowed by current key format.
544 * @c: UBIFS file-system description object
545 */
546static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
547{
548 switch (c->key_fmt) {
549 case UBIFS_SIMPLE_KEY_FMT:
550 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
551 default:
552 return 0;
553 }
554}
e3c3efc2 555
1e51764a 556#endif /* !__UBIFS_KEY_H__ */