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