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9eefe2a2 SR |
1 | /* |
2 | * This file is part of UBIFS. | |
3 | * | |
4 | * Copyright (C) 2006-2008 Nokia Corporation. | |
5 | * | |
ff94bc40 | 6 | * SPDX-License-Identifier: GPL-2.0+ |
9eefe2a2 SR |
7 | * |
8 | * Authors: Artem Bityutskiy (Битюцкий Артём) | |
9 | * Adrian Hunter | |
10 | */ | |
11 | ||
12 | /* | |
13 | * This header contains various key-related definitions and helper function. | |
14 | * UBIFS allows several key schemes, so we access key fields only via these | |
15 | * helpers. At the moment only one key scheme is supported. | |
16 | * | |
17 | * Simple key scheme | |
18 | * ~~~~~~~~~~~~~~~~~ | |
19 | * | |
20 | * Keys are 64-bits long. First 32-bits are inode number (parent inode number | |
21 | * in case of direntry key). Next 3 bits are node type. The last 29 bits are | |
22 | * 4KiB offset in case of inode node, and direntry hash in case of a direntry | |
23 | * node. We use "r5" hash borrowed from reiserfs. | |
24 | */ | |
25 | ||
26 | #ifndef __UBIFS_KEY_H__ | |
27 | #define __UBIFS_KEY_H__ | |
28 | ||
29 | /** | |
30 | * key_mask_hash - mask a valid hash value. | |
31 | * @val: value to be masked | |
32 | * | |
33 | * We use hash values as offset in directories, so values %0 and %1 are | |
34 | * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This | |
35 | * function makes sure the reserved values are not used. | |
36 | */ | |
37 | static inline uint32_t key_mask_hash(uint32_t hash) | |
38 | { | |
39 | hash &= UBIFS_S_KEY_HASH_MASK; | |
40 | if (unlikely(hash <= 2)) | |
41 | hash += 3; | |
42 | return hash; | |
43 | } | |
44 | ||
45 | /** | |
46 | * key_r5_hash - R5 hash function (borrowed from reiserfs). | |
47 | * @s: direntry name | |
48 | * @len: name length | |
49 | */ | |
50 | static inline uint32_t key_r5_hash(const char *s, int len) | |
51 | { | |
52 | uint32_t a = 0; | |
53 | const signed char *str = (const signed char *)s; | |
54 | ||
55 | while (*str) { | |
56 | a += *str << 4; | |
57 | a += *str >> 4; | |
58 | a *= 11; | |
59 | str++; | |
60 | } | |
61 | ||
62 | return key_mask_hash(a); | |
63 | } | |
64 | ||
65 | /** | |
66 | * key_test_hash - testing hash function. | |
67 | * @str: direntry name | |
68 | * @len: name length | |
69 | */ | |
70 | static inline uint32_t key_test_hash(const char *str, int len) | |
71 | { | |
72 | uint32_t a = 0; | |
73 | ||
74 | len = min_t(uint32_t, len, 4); | |
75 | memcpy(&a, str, len); | |
76 | return key_mask_hash(a); | |
77 | } | |
78 | ||
79 | /** | |
80 | * ino_key_init - initialize inode key. | |
81 | * @c: UBIFS file-system description object | |
82 | * @key: key to initialize | |
83 | * @inum: inode number | |
84 | */ | |
85 | static inline void ino_key_init(const struct ubifs_info *c, | |
86 | union ubifs_key *key, ino_t inum) | |
87 | { | |
88 | key->u32[0] = inum; | |
89 | key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS; | |
90 | } | |
91 | ||
92 | /** | |
93 | * ino_key_init_flash - initialize on-flash inode key. | |
94 | * @c: UBIFS file-system description object | |
95 | * @k: key to initialize | |
96 | * @inum: inode number | |
97 | */ | |
98 | static inline void ino_key_init_flash(const struct ubifs_info *c, void *k, | |
99 | ino_t inum) | |
100 | { | |
101 | union ubifs_key *key = k; | |
102 | ||
103 | key->j32[0] = cpu_to_le32(inum); | |
104 | key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS); | |
105 | memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
106 | } | |
107 | ||
108 | /** | |
109 | * lowest_ino_key - get the lowest possible inode key. | |
110 | * @c: UBIFS file-system description object | |
111 | * @key: key to initialize | |
112 | * @inum: inode number | |
113 | */ | |
114 | static inline void lowest_ino_key(const struct ubifs_info *c, | |
115 | union ubifs_key *key, ino_t inum) | |
116 | { | |
117 | key->u32[0] = inum; | |
118 | key->u32[1] = 0; | |
119 | } | |
120 | ||
121 | /** | |
122 | * highest_ino_key - get the highest possible inode key. | |
123 | * @c: UBIFS file-system description object | |
124 | * @key: key to initialize | |
125 | * @inum: inode number | |
126 | */ | |
127 | static inline void highest_ino_key(const struct ubifs_info *c, | |
128 | union ubifs_key *key, ino_t inum) | |
129 | { | |
130 | key->u32[0] = inum; | |
131 | key->u32[1] = 0xffffffff; | |
132 | } | |
133 | ||
134 | /** | |
135 | * dent_key_init - initialize directory entry key. | |
136 | * @c: UBIFS file-system description object | |
137 | * @key: key to initialize | |
138 | * @inum: parent inode number | |
139 | * @nm: direntry name and length | |
140 | */ | |
141 | static inline void dent_key_init(const struct ubifs_info *c, | |
142 | union ubifs_key *key, ino_t inum, | |
143 | const struct qstr *nm) | |
144 | { | |
145 | uint32_t hash = c->key_hash(nm->name, nm->len); | |
146 | ||
147 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
148 | key->u32[0] = inum; | |
149 | key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS); | |
150 | } | |
151 | ||
152 | /** | |
153 | * dent_key_init_hash - initialize directory entry key without re-calculating | |
154 | * hash function. | |
155 | * @c: UBIFS file-system description object | |
156 | * @key: key to initialize | |
157 | * @inum: parent inode number | |
158 | * @hash: direntry name hash | |
159 | */ | |
160 | static inline void dent_key_init_hash(const struct ubifs_info *c, | |
161 | union ubifs_key *key, ino_t inum, | |
162 | uint32_t hash) | |
163 | { | |
164 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
165 | key->u32[0] = inum; | |
166 | key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS); | |
167 | } | |
168 | ||
169 | /** | |
170 | * dent_key_init_flash - initialize on-flash directory entry key. | |
171 | * @c: UBIFS file-system description object | |
172 | * @k: key to initialize | |
173 | * @inum: parent inode number | |
174 | * @nm: direntry name and length | |
175 | */ | |
176 | static inline void dent_key_init_flash(const struct ubifs_info *c, void *k, | |
177 | ino_t inum, const struct qstr *nm) | |
178 | { | |
179 | union ubifs_key *key = k; | |
180 | uint32_t hash = c->key_hash(nm->name, nm->len); | |
181 | ||
182 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
183 | key->j32[0] = cpu_to_le32(inum); | |
184 | key->j32[1] = cpu_to_le32(hash | | |
185 | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS)); | |
186 | memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
187 | } | |
188 | ||
189 | /** | |
190 | * lowest_dent_key - get the lowest possible directory entry key. | |
191 | * @c: UBIFS file-system description object | |
192 | * @key: where to store the lowest key | |
193 | * @inum: parent inode number | |
194 | */ | |
195 | static inline void lowest_dent_key(const struct ubifs_info *c, | |
196 | union ubifs_key *key, ino_t inum) | |
197 | { | |
198 | key->u32[0] = inum; | |
199 | key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS; | |
200 | } | |
201 | ||
202 | /** | |
203 | * xent_key_init - initialize extended attribute entry key. | |
204 | * @c: UBIFS file-system description object | |
205 | * @key: key to initialize | |
206 | * @inum: host inode number | |
207 | * @nm: extended attribute entry name and length | |
208 | */ | |
209 | static inline void xent_key_init(const struct ubifs_info *c, | |
210 | union ubifs_key *key, ino_t inum, | |
211 | const struct qstr *nm) | |
212 | { | |
213 | uint32_t hash = c->key_hash(nm->name, nm->len); | |
214 | ||
215 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
216 | key->u32[0] = inum; | |
217 | key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS); | |
218 | } | |
219 | ||
9eefe2a2 SR |
220 | /** |
221 | * xent_key_init_flash - initialize on-flash extended attribute entry key. | |
222 | * @c: UBIFS file-system description object | |
223 | * @k: key to initialize | |
224 | * @inum: host inode number | |
225 | * @nm: extended attribute entry name and length | |
226 | */ | |
227 | static inline void xent_key_init_flash(const struct ubifs_info *c, void *k, | |
228 | ino_t inum, const struct qstr *nm) | |
229 | { | |
230 | union ubifs_key *key = k; | |
231 | uint32_t hash = c->key_hash(nm->name, nm->len); | |
232 | ||
233 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
234 | key->j32[0] = cpu_to_le32(inum); | |
235 | key->j32[1] = cpu_to_le32(hash | | |
236 | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS)); | |
237 | memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
238 | } | |
239 | ||
240 | /** | |
241 | * lowest_xent_key - get the lowest possible extended attribute entry key. | |
242 | * @c: UBIFS file-system description object | |
243 | * @key: where to store the lowest key | |
244 | * @inum: host inode number | |
245 | */ | |
246 | static inline void lowest_xent_key(const struct ubifs_info *c, | |
247 | union ubifs_key *key, ino_t inum) | |
248 | { | |
249 | key->u32[0] = inum; | |
250 | key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS; | |
251 | } | |
252 | ||
253 | /** | |
254 | * data_key_init - initialize data key. | |
255 | * @c: UBIFS file-system description object | |
256 | * @key: key to initialize | |
257 | * @inum: inode number | |
258 | * @block: block number | |
259 | */ | |
260 | static inline void data_key_init(const struct ubifs_info *c, | |
261 | union ubifs_key *key, ino_t inum, | |
262 | unsigned int block) | |
263 | { | |
264 | ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK)); | |
265 | key->u32[0] = inum; | |
266 | key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS); | |
267 | } | |
268 | ||
269 | /** | |
ff94bc40 | 270 | * highest_data_key - get the highest possible data key for an inode. |
9eefe2a2 | 271 | * @c: UBIFS file-system description object |
ff94bc40 | 272 | * @key: key to initialize |
9eefe2a2 | 273 | * @inum: inode number |
9eefe2a2 | 274 | */ |
ff94bc40 HS |
275 | static inline void highest_data_key(const struct ubifs_info *c, |
276 | union ubifs_key *key, ino_t inum) | |
9eefe2a2 | 277 | { |
ff94bc40 | 278 | data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK); |
9eefe2a2 SR |
279 | } |
280 | ||
281 | /** | |
282 | * trun_key_init - initialize truncation node key. | |
283 | * @c: UBIFS file-system description object | |
284 | * @key: key to initialize | |
285 | * @inum: inode number | |
286 | * | |
287 | * Note, UBIFS does not have truncation keys on the media and this function is | |
288 | * only used for purposes of replay. | |
289 | */ | |
290 | static inline void trun_key_init(const struct ubifs_info *c, | |
291 | union ubifs_key *key, ino_t inum) | |
292 | { | |
293 | key->u32[0] = inum; | |
294 | key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS; | |
295 | } | |
296 | ||
ff94bc40 HS |
297 | /** |
298 | * invalid_key_init - initialize invalid node key. | |
299 | * @c: UBIFS file-system description object | |
300 | * @key: key to initialize | |
301 | * | |
302 | * This is a helper function which marks a @key object as invalid. | |
303 | */ | |
304 | static inline void invalid_key_init(const struct ubifs_info *c, | |
305 | union ubifs_key *key) | |
306 | { | |
307 | key->u32[0] = 0xDEADBEAF; | |
308 | key->u32[1] = UBIFS_INVALID_KEY; | |
309 | } | |
310 | ||
9eefe2a2 SR |
311 | /** |
312 | * key_type - get key type. | |
313 | * @c: UBIFS file-system description object | |
314 | * @key: key to get type of | |
315 | */ | |
316 | static inline int key_type(const struct ubifs_info *c, | |
317 | const union ubifs_key *key) | |
318 | { | |
319 | return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS; | |
320 | } | |
321 | ||
322 | /** | |
323 | * key_type_flash - get type of a on-flash formatted key. | |
324 | * @c: UBIFS file-system description object | |
325 | * @k: key to get type of | |
326 | */ | |
327 | static inline int key_type_flash(const struct ubifs_info *c, const void *k) | |
328 | { | |
329 | const union ubifs_key *key = k; | |
330 | ||
331 | return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS; | |
332 | } | |
333 | ||
334 | /** | |
335 | * key_inum - fetch inode number from key. | |
336 | * @c: UBIFS file-system description object | |
337 | * @k: key to fetch inode number from | |
338 | */ | |
339 | static inline ino_t key_inum(const struct ubifs_info *c, const void *k) | |
340 | { | |
341 | const union ubifs_key *key = k; | |
342 | ||
343 | return key->u32[0]; | |
344 | } | |
345 | ||
346 | /** | |
347 | * key_inum_flash - fetch inode number from an on-flash formatted key. | |
348 | * @c: UBIFS file-system description object | |
349 | * @k: key to fetch inode number from | |
350 | */ | |
351 | static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k) | |
352 | { | |
353 | const union ubifs_key *key = k; | |
354 | ||
355 | return le32_to_cpu(key->j32[0]); | |
356 | } | |
357 | ||
358 | /** | |
359 | * key_hash - get directory entry hash. | |
360 | * @c: UBIFS file-system description object | |
361 | * @key: the key to get hash from | |
362 | */ | |
ff94bc40 HS |
363 | static inline uint32_t key_hash(const struct ubifs_info *c, |
364 | const union ubifs_key *key) | |
9eefe2a2 SR |
365 | { |
366 | return key->u32[1] & UBIFS_S_KEY_HASH_MASK; | |
367 | } | |
368 | ||
369 | /** | |
370 | * key_hash_flash - get directory entry hash from an on-flash formatted key. | |
371 | * @c: UBIFS file-system description object | |
372 | * @k: the key to get hash from | |
373 | */ | |
ff94bc40 | 374 | static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k) |
9eefe2a2 SR |
375 | { |
376 | const union ubifs_key *key = k; | |
377 | ||
378 | return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK; | |
379 | } | |
380 | ||
381 | /** | |
382 | * key_block - get data block number. | |
383 | * @c: UBIFS file-system description object | |
384 | * @key: the key to get the block number from | |
385 | */ | |
386 | static inline unsigned int key_block(const struct ubifs_info *c, | |
387 | const union ubifs_key *key) | |
388 | { | |
389 | return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK; | |
390 | } | |
391 | ||
392 | /** | |
393 | * key_block_flash - get data block number from an on-flash formatted key. | |
394 | * @c: UBIFS file-system description object | |
395 | * @k: the key to get the block number from | |
396 | */ | |
397 | static inline unsigned int key_block_flash(const struct ubifs_info *c, | |
398 | const void *k) | |
399 | { | |
400 | const union ubifs_key *key = k; | |
401 | ||
402 | return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK; | |
403 | } | |
404 | ||
405 | /** | |
406 | * key_read - transform a key to in-memory format. | |
407 | * @c: UBIFS file-system description object | |
408 | * @from: the key to transform | |
409 | * @to: the key to store the result | |
410 | */ | |
411 | static inline void key_read(const struct ubifs_info *c, const void *from, | |
412 | union ubifs_key *to) | |
413 | { | |
414 | const union ubifs_key *f = from; | |
415 | ||
416 | to->u32[0] = le32_to_cpu(f->j32[0]); | |
417 | to->u32[1] = le32_to_cpu(f->j32[1]); | |
418 | } | |
419 | ||
420 | /** | |
421 | * key_write - transform a key from in-memory format. | |
422 | * @c: UBIFS file-system description object | |
423 | * @from: the key to transform | |
424 | * @to: the key to store the result | |
425 | */ | |
426 | static inline void key_write(const struct ubifs_info *c, | |
427 | const union ubifs_key *from, void *to) | |
428 | { | |
429 | union ubifs_key *t = to; | |
430 | ||
431 | t->j32[0] = cpu_to_le32(from->u32[0]); | |
432 | t->j32[1] = cpu_to_le32(from->u32[1]); | |
433 | memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
434 | } | |
435 | ||
436 | /** | |
437 | * key_write_idx - transform a key from in-memory format for the index. | |
438 | * @c: UBIFS file-system description object | |
439 | * @from: the key to transform | |
440 | * @to: the key to store the result | |
441 | */ | |
442 | static inline void key_write_idx(const struct ubifs_info *c, | |
443 | const union ubifs_key *from, void *to) | |
444 | { | |
445 | union ubifs_key *t = to; | |
446 | ||
447 | t->j32[0] = cpu_to_le32(from->u32[0]); | |
448 | t->j32[1] = cpu_to_le32(from->u32[1]); | |
449 | } | |
450 | ||
451 | /** | |
452 | * key_copy - copy a key. | |
453 | * @c: UBIFS file-system description object | |
454 | * @from: the key to copy from | |
455 | * @to: the key to copy to | |
456 | */ | |
457 | static inline void key_copy(const struct ubifs_info *c, | |
458 | const union ubifs_key *from, union ubifs_key *to) | |
459 | { | |
460 | to->u64[0] = from->u64[0]; | |
461 | } | |
462 | ||
463 | /** | |
464 | * keys_cmp - compare keys. | |
465 | * @c: UBIFS file-system description object | |
466 | * @key1: the first key to compare | |
467 | * @key2: the second key to compare | |
468 | * | |
469 | * This function compares 2 keys and returns %-1 if @key1 is less than | |
470 | * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2. | |
471 | */ | |
472 | static inline int keys_cmp(const struct ubifs_info *c, | |
473 | const union ubifs_key *key1, | |
474 | const union ubifs_key *key2) | |
475 | { | |
476 | if (key1->u32[0] < key2->u32[0]) | |
477 | return -1; | |
478 | if (key1->u32[0] > key2->u32[0]) | |
479 | return 1; | |
480 | if (key1->u32[1] < key2->u32[1]) | |
481 | return -1; | |
482 | if (key1->u32[1] > key2->u32[1]) | |
483 | return 1; | |
484 | ||
485 | return 0; | |
486 | } | |
487 | ||
488 | /** | |
489 | * keys_eq - determine if keys are equivalent. | |
490 | * @c: UBIFS file-system description object | |
491 | * @key1: the first key to compare | |
492 | * @key2: the second key to compare | |
493 | * | |
494 | * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and | |
495 | * %0 if not. | |
496 | */ | |
497 | static inline int keys_eq(const struct ubifs_info *c, | |
498 | const union ubifs_key *key1, | |
499 | const union ubifs_key *key2) | |
500 | { | |
501 | if (key1->u32[0] != key2->u32[0]) | |
502 | return 0; | |
503 | if (key1->u32[1] != key2->u32[1]) | |
504 | return 0; | |
505 | return 1; | |
506 | } | |
507 | ||
508 | /** | |
509 | * is_hash_key - is a key vulnerable to hash collisions. | |
510 | * @c: UBIFS file-system description object | |
511 | * @key: key | |
512 | * | |
513 | * This function returns %1 if @key is a hashed key or %0 otherwise. | |
514 | */ | |
515 | static inline int is_hash_key(const struct ubifs_info *c, | |
516 | const union ubifs_key *key) | |
517 | { | |
518 | int type = key_type(c, key); | |
519 | ||
520 | return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY; | |
521 | } | |
522 | ||
523 | /** | |
524 | * key_max_inode_size - get maximum file size allowed by current key format. | |
525 | * @c: UBIFS file-system description object | |
526 | */ | |
527 | static inline unsigned long long key_max_inode_size(const struct ubifs_info *c) | |
528 | { | |
529 | switch (c->key_fmt) { | |
530 | case UBIFS_SIMPLE_KEY_FMT: | |
531 | return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE; | |
532 | default: | |
533 | return 0; | |
534 | } | |
535 | } | |
ff94bc40 | 536 | |
9eefe2a2 | 537 | #endif /* !__UBIFS_KEY_H__ */ |