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Stefan Roese9eefe2a2009-03-19 15:35:05 +01001/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
Heiko Schocherff94bc42014-06-24 10:10:04 +02006 * SPDX-License-Identifier: GPL-2.0+
Stefan Roese9eefe2a2009-03-19 15:35:05 +01007 *
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 */
37static 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 */
50static 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 */
70static 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 */
85static 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 */
98static 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 */
114static 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 */
127static 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 */
141static 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 */
160static 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 */
176static 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 */
195static 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 */
209static 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
220/**
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100221 * 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 */
227static 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 */
246static 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 */
260static 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/**
Heiko Schocherff94bc42014-06-24 10:10:04 +0200270 * highest_data_key - get the highest possible data key for an inode.
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100271 * @c: UBIFS file-system description object
Heiko Schocherff94bc42014-06-24 10:10:04 +0200272 * @key: key to initialize
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100273 * @inum: inode number
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100274 */
Heiko Schocherff94bc42014-06-24 10:10:04 +0200275static inline void highest_data_key(const struct ubifs_info *c,
276 union ubifs_key *key, ino_t inum)
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100277{
Heiko Schocherff94bc42014-06-24 10:10:04 +0200278 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100279}
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 */
290static 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
297/**
Heiko Schocherff94bc42014-06-24 10:10:04 +0200298 * 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 */
304static 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
311/**
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100312 * key_type - get key type.
313 * @c: UBIFS file-system description object
314 * @key: key to get type of
315 */
316static 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 */
327static 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 */
339static 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 */
351static 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 */
Heiko Schocherff94bc42014-06-24 10:10:04 +0200363static inline uint32_t key_hash(const struct ubifs_info *c,
364 const union ubifs_key *key)
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100365{
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 */
Heiko Schocherff94bc42014-06-24 10:10:04 +0200374static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100375{
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 */
386static 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 */
397static 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 */
411static 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 */
426static 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 */
442static 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 */
457static 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 */
472static 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 */
497static 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 */
515static 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 */
527static 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}
Heiko Schocherff94bc42014-06-24 10:10:04 +0200536
Stefan Roese9eefe2a2009-03-19 15:35:05 +0100537#endif /* !__UBIFS_KEY_H__ */