xref: /openbmc/u-boot/fs/ubifs/key.h (revision 85231c08) 
1 /*
2  * This file is part of UBIFS.
3  *
4  * Copyright (C) 2006-2008 Nokia Corporation.
5  *
6  * SPDX-License-Identifier:	GPL-2.0+
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 
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 /**
270  * highest_data_key - get the highest possible data key for an inode.
271  * @c: UBIFS file-system description object
272  * @key: key to initialize
273  * @inum: inode number
274  */
275 static inline void highest_data_key(const struct ubifs_info *c,
276 				   union ubifs_key *key, ino_t inum)
277 {
278 	data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
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 
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 
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  */
363 static inline uint32_t key_hash(const struct ubifs_info *c,
364 				const union ubifs_key *key)
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  */
374 static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
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 }
536 
537 #endif /* !__UBIFS_KEY_H__ */
538