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1e51764a AB |
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 | ||
170eb55f DY |
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 | ||
1e51764a AB |
43 | #ifndef __UBIFS_KEY_H__ |
44 | #define __UBIFS_KEY_H__ | |
45 | ||
5dd7cbc0 KM |
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 | */ | |
54 | static 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 | ||
1e51764a AB |
62 | /** |
63 | * key_r5_hash - R5 hash function (borrowed from reiserfs). | |
64 | * @s: direntry name | |
65 | * @len: name length | |
66 | */ | |
67 | static 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--) { |
1e51764a AB |
73 | a += *str << 4; |
74 | a += *str >> 4; | |
75 | a *= 11; | |
76 | str++; | |
77 | } | |
78 | ||
5dd7cbc0 | 79 | return key_mask_hash(a); |
1e51764a AB |
80 | } |
81 | ||
82 | /** | |
83 | * key_test_hash - testing hash function. | |
84 | * @str: direntry name | |
85 | * @len: name length | |
86 | */ | |
87 | static 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); |
1e51764a AB |
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 | */ | |
102 | static 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 | */ | |
115 | static 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 | */ | |
131 | static 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 | */ | |
144 | static 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! |
1e51764a AB |
157 | */ |
158 | static 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 AB |
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_hash - initialize directory entry key without re-calculating | |
171 | * hash function. | |
172 | * @c: UBIFS file-system description object | |
173 | * @key: key to initialize | |
174 | * @inum: parent inode number | |
175 | * @hash: direntry name hash | |
176 | */ | |
177 | static inline void dent_key_init_hash(const struct ubifs_info *c, | |
178 | union ubifs_key *key, ino_t inum, | |
179 | uint32_t hash) | |
180 | { | |
181 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
182 | key->u32[0] = inum; | |
183 | key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS); | |
184 | } | |
185 | ||
186 | /** | |
187 | * dent_key_init_flash - initialize on-flash directory entry key. | |
188 | * @c: UBIFS file-system description object | |
189 | * @k: key to initialize | |
190 | * @inum: parent inode number | |
191 | * @nm: direntry name and length | |
192 | */ | |
193 | static inline void dent_key_init_flash(const struct ubifs_info *c, void *k, | |
f4f61d2c RW |
194 | ino_t inum, |
195 | const struct fscrypt_name *nm) | |
1e51764a AB |
196 | { |
197 | union ubifs_key *key = k; | |
f4f61d2c | 198 | uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm)); |
1e51764a AB |
199 | |
200 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
201 | key->j32[0] = cpu_to_le32(inum); | |
202 | key->j32[1] = cpu_to_le32(hash | | |
203 | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS)); | |
204 | memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
205 | } | |
206 | ||
207 | /** | |
208 | * lowest_dent_key - get the lowest possible directory entry key. | |
209 | * @c: UBIFS file-system description object | |
210 | * @key: where to store the lowest key | |
211 | * @inum: parent inode number | |
212 | */ | |
213 | static inline void lowest_dent_key(const struct ubifs_info *c, | |
214 | union ubifs_key *key, ino_t inum) | |
215 | { | |
216 | key->u32[0] = inum; | |
217 | key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS; | |
218 | } | |
219 | ||
220 | /** | |
221 | * xent_key_init - initialize extended attribute entry key. | |
222 | * @c: UBIFS file-system description object | |
223 | * @key: key to initialize | |
224 | * @inum: host inode number | |
225 | * @nm: extended attribute entry name and length | |
226 | */ | |
227 | static inline void xent_key_init(const struct ubifs_info *c, | |
228 | union ubifs_key *key, ino_t inum, | |
f4f61d2c | 229 | const struct fscrypt_name *nm) |
1e51764a | 230 | { |
f4f61d2c | 231 | uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm)); |
1e51764a AB |
232 | |
233 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
234 | key->u32[0] = inum; | |
235 | key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS); | |
236 | } | |
237 | ||
1e51764a AB |
238 | /** |
239 | * xent_key_init_flash - initialize on-flash extended attribute entry key. | |
240 | * @c: UBIFS file-system description object | |
241 | * @k: key to initialize | |
242 | * @inum: host inode number | |
243 | * @nm: extended attribute entry name and length | |
244 | */ | |
245 | static inline void xent_key_init_flash(const struct ubifs_info *c, void *k, | |
f4f61d2c | 246 | ino_t inum, const struct fscrypt_name *nm) |
1e51764a AB |
247 | { |
248 | union ubifs_key *key = k; | |
f4f61d2c | 249 | uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm)); |
1e51764a AB |
250 | |
251 | ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK)); | |
252 | key->j32[0] = cpu_to_le32(inum); | |
253 | key->j32[1] = cpu_to_le32(hash | | |
254 | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS)); | |
255 | memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
256 | } | |
257 | ||
258 | /** | |
259 | * lowest_xent_key - get the lowest possible extended attribute entry key. | |
260 | * @c: UBIFS file-system description object | |
261 | * @key: where to store the lowest key | |
262 | * @inum: host inode number | |
263 | */ | |
264 | static inline void lowest_xent_key(const struct ubifs_info *c, | |
265 | union ubifs_key *key, ino_t inum) | |
266 | { | |
267 | key->u32[0] = inum; | |
268 | key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS; | |
269 | } | |
270 | ||
271 | /** | |
272 | * data_key_init - initialize data key. | |
273 | * @c: UBIFS file-system description object | |
274 | * @key: key to initialize | |
275 | * @inum: inode number | |
276 | * @block: block number | |
277 | */ | |
278 | static inline void data_key_init(const struct ubifs_info *c, | |
279 | union ubifs_key *key, ino_t inum, | |
280 | unsigned int block) | |
281 | { | |
282 | ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK)); | |
283 | key->u32[0] = inum; | |
284 | key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS); | |
285 | } | |
286 | ||
e3c3efc2 AB |
287 | /** |
288 | * highest_data_key - get the highest possible data key for an inode. | |
289 | * @c: UBIFS file-system description object | |
290 | * @key: key to initialize | |
291 | * @inum: inode number | |
292 | */ | |
293 | static inline void highest_data_key(const struct ubifs_info *c, | |
294 | union ubifs_key *key, ino_t inum) | |
295 | { | |
296 | data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK); | |
297 | } | |
298 | ||
1e51764a AB |
299 | /** |
300 | * trun_key_init - initialize truncation node key. | |
301 | * @c: UBIFS file-system description object | |
302 | * @key: key to initialize | |
303 | * @inum: inode number | |
304 | * | |
305 | * Note, UBIFS does not have truncation keys on the media and this function is | |
306 | * only used for purposes of replay. | |
307 | */ | |
308 | static inline void trun_key_init(const struct ubifs_info *c, | |
309 | union ubifs_key *key, ino_t inum) | |
310 | { | |
311 | key->u32[0] = inum; | |
312 | key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS; | |
313 | } | |
314 | ||
ba2f48f7 AB |
315 | /** |
316 | * invalid_key_init - initialize invalid node key. | |
317 | * @c: UBIFS file-system description object | |
318 | * @key: key to initialize | |
319 | * | |
320 | * This is a helper function which marks a @key object as invalid. | |
321 | */ | |
322 | static inline void invalid_key_init(const struct ubifs_info *c, | |
323 | union ubifs_key *key) | |
324 | { | |
325 | key->u32[0] = 0xDEADBEAF; | |
326 | key->u32[1] = UBIFS_INVALID_KEY; | |
327 | } | |
328 | ||
1e51764a AB |
329 | /** |
330 | * key_type - get key type. | |
331 | * @c: UBIFS file-system description object | |
332 | * @key: key to get type of | |
333 | */ | |
334 | static inline int key_type(const struct ubifs_info *c, | |
335 | const union ubifs_key *key) | |
336 | { | |
337 | return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS; | |
338 | } | |
339 | ||
340 | /** | |
341 | * key_type_flash - get type of a on-flash formatted key. | |
342 | * @c: UBIFS file-system description object | |
343 | * @k: key to get type of | |
344 | */ | |
345 | static inline int key_type_flash(const struct ubifs_info *c, const void *k) | |
346 | { | |
347 | const union ubifs_key *key = k; | |
348 | ||
0ecb9529 | 349 | return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS; |
1e51764a AB |
350 | } |
351 | ||
352 | /** | |
353 | * key_inum - fetch inode number from key. | |
354 | * @c: UBIFS file-system description object | |
355 | * @k: key to fetch inode number from | |
356 | */ | |
357 | static inline ino_t key_inum(const struct ubifs_info *c, const void *k) | |
358 | { | |
359 | const union ubifs_key *key = k; | |
360 | ||
361 | return key->u32[0]; | |
362 | } | |
363 | ||
364 | /** | |
365 | * key_inum_flash - fetch inode number from an on-flash formatted key. | |
366 | * @c: UBIFS file-system description object | |
367 | * @k: key to fetch inode number from | |
368 | */ | |
369 | static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k) | |
370 | { | |
371 | const union ubifs_key *key = k; | |
372 | ||
373 | return le32_to_cpu(key->j32[0]); | |
374 | } | |
375 | ||
376 | /** | |
377 | * key_hash - get directory entry hash. | |
378 | * @c: UBIFS file-system description object | |
379 | * @key: the key to get hash from | |
380 | */ | |
cb4f952d AB |
381 | static inline uint32_t key_hash(const struct ubifs_info *c, |
382 | const union ubifs_key *key) | |
1e51764a AB |
383 | { |
384 | return key->u32[1] & UBIFS_S_KEY_HASH_MASK; | |
385 | } | |
386 | ||
387 | /** | |
388 | * key_hash_flash - get directory entry hash from an on-flash formatted key. | |
389 | * @c: UBIFS file-system description object | |
390 | * @k: the key to get hash from | |
391 | */ | |
cb4f952d | 392 | static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k) |
1e51764a AB |
393 | { |
394 | const union ubifs_key *key = k; | |
395 | ||
396 | return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK; | |
397 | } | |
398 | ||
399 | /** | |
400 | * key_block - get data block number. | |
401 | * @c: UBIFS file-system description object | |
402 | * @key: the key to get the block number from | |
403 | */ | |
404 | static inline unsigned int key_block(const struct ubifs_info *c, | |
405 | const union ubifs_key *key) | |
406 | { | |
407 | return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK; | |
408 | } | |
409 | ||
410 | /** | |
411 | * key_block_flash - get data block number from an on-flash formatted key. | |
412 | * @c: UBIFS file-system description object | |
413 | * @k: the key to get the block number from | |
414 | */ | |
415 | static inline unsigned int key_block_flash(const struct ubifs_info *c, | |
416 | const void *k) | |
417 | { | |
418 | const union ubifs_key *key = k; | |
419 | ||
0ecb9529 | 420 | return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK; |
1e51764a AB |
421 | } |
422 | ||
423 | /** | |
424 | * key_read - transform a key to in-memory format. | |
425 | * @c: UBIFS file-system description object | |
426 | * @from: the key to transform | |
427 | * @to: the key to store the result | |
428 | */ | |
429 | static inline void key_read(const struct ubifs_info *c, const void *from, | |
430 | union ubifs_key *to) | |
431 | { | |
432 | const union ubifs_key *f = from; | |
433 | ||
434 | to->u32[0] = le32_to_cpu(f->j32[0]); | |
435 | to->u32[1] = le32_to_cpu(f->j32[1]); | |
436 | } | |
437 | ||
438 | /** | |
439 | * key_write - transform a key from in-memory format. | |
440 | * @c: UBIFS file-system description object | |
441 | * @from: the key to transform | |
442 | * @to: the key to store the result | |
443 | */ | |
444 | static inline void key_write(const struct ubifs_info *c, | |
445 | const union ubifs_key *from, void *to) | |
446 | { | |
447 | union ubifs_key *t = to; | |
448 | ||
449 | t->j32[0] = cpu_to_le32(from->u32[0]); | |
450 | t->j32[1] = cpu_to_le32(from->u32[1]); | |
451 | memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8); | |
452 | } | |
453 | ||
454 | /** | |
455 | * key_write_idx - transform a key from in-memory format for the index. | |
456 | * @c: UBIFS file-system description object | |
457 | * @from: the key to transform | |
458 | * @to: the key to store the result | |
459 | */ | |
460 | static inline void key_write_idx(const struct ubifs_info *c, | |
461 | const union ubifs_key *from, void *to) | |
462 | { | |
463 | union ubifs_key *t = to; | |
464 | ||
465 | t->j32[0] = cpu_to_le32(from->u32[0]); | |
466 | t->j32[1] = cpu_to_le32(from->u32[1]); | |
467 | } | |
468 | ||
469 | /** | |
470 | * key_copy - copy a key. | |
471 | * @c: UBIFS file-system description object | |
472 | * @from: the key to copy from | |
473 | * @to: the key to copy to | |
474 | */ | |
475 | static inline void key_copy(const struct ubifs_info *c, | |
476 | const union ubifs_key *from, union ubifs_key *to) | |
477 | { | |
478 | to->u64[0] = from->u64[0]; | |
479 | } | |
480 | ||
481 | /** | |
482 | * keys_cmp - compare keys. | |
483 | * @c: UBIFS file-system description object | |
484 | * @key1: the first key to compare | |
485 | * @key2: the second key to compare | |
486 | * | |
487 | * This function compares 2 keys and returns %-1 if @key1 is less than | |
4793e7c5 | 488 | * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2. |
1e51764a AB |
489 | */ |
490 | static inline int keys_cmp(const struct ubifs_info *c, | |
491 | const union ubifs_key *key1, | |
492 | const union ubifs_key *key2) | |
493 | { | |
494 | if (key1->u32[0] < key2->u32[0]) | |
495 | return -1; | |
496 | if (key1->u32[0] > key2->u32[0]) | |
497 | return 1; | |
498 | if (key1->u32[1] < key2->u32[1]) | |
499 | return -1; | |
500 | if (key1->u32[1] > key2->u32[1]) | |
501 | return 1; | |
502 | ||
503 | return 0; | |
504 | } | |
505 | ||
4793e7c5 AH |
506 | /** |
507 | * keys_eq - determine if keys are equivalent. | |
508 | * @c: UBIFS file-system description object | |
509 | * @key1: the first key to compare | |
510 | * @key2: the second key to compare | |
511 | * | |
512 | * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and | |
513 | * %0 if not. | |
514 | */ | |
515 | static inline int keys_eq(const struct ubifs_info *c, | |
516 | const union ubifs_key *key1, | |
517 | const union ubifs_key *key2) | |
518 | { | |
519 | if (key1->u32[0] != key2->u32[0]) | |
520 | return 0; | |
521 | if (key1->u32[1] != key2->u32[1]) | |
522 | return 0; | |
523 | return 1; | |
524 | } | |
525 | ||
1e51764a AB |
526 | /** |
527 | * is_hash_key - is a key vulnerable to hash collisions. | |
528 | * @c: UBIFS file-system description object | |
529 | * @key: key | |
530 | * | |
531 | * This function returns %1 if @key is a hashed key or %0 otherwise. | |
532 | */ | |
533 | static inline int is_hash_key(const struct ubifs_info *c, | |
534 | const union ubifs_key *key) | |
535 | { | |
536 | int type = key_type(c, key); | |
537 | ||
538 | return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY; | |
539 | } | |
540 | ||
541 | /** | |
542 | * key_max_inode_size - get maximum file size allowed by current key format. | |
543 | * @c: UBIFS file-system description object | |
544 | */ | |
545 | static inline unsigned long long key_max_inode_size(const struct ubifs_info *c) | |
546 | { | |
547 | switch (c->key_fmt) { | |
548 | case UBIFS_SIMPLE_KEY_FMT: | |
549 | return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE; | |
550 | default: | |
551 | return 0; | |
552 | } | |
553 | } | |
e3c3efc2 | 554 | |
1e51764a | 555 | #endif /* !__UBIFS_KEY_H__ */ |