1 /* 2 * This implementation is based on code from uClibc-0.9.30.3 but was 3 * modified and extended for use within U-Boot. 4 * 5 * Copyright (C) 2010 Wolfgang Denk <wd@denx.de> 6 * 7 * Original license header: 8 * 9 * Copyright (C) 1993, 1995, 1996, 1997, 2002 Free Software Foundation, Inc. 10 * This file is part of the GNU C Library. 11 * Contributed by Ulrich Drepper <drepper@gnu.ai.mit.edu>, 1993. 12 * 13 * The GNU C Library is free software; you can redistribute it and/or 14 * modify it under the terms of the GNU Lesser General Public 15 * License as published by the Free Software Foundation; either 16 * version 2.1 of the License, or (at your option) any later version. 17 * 18 * The GNU C Library is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 21 * Lesser General Public License for more details. 22 * 23 * You should have received a copy of the GNU Lesser General Public 24 * License along with the GNU C Library; if not, write to the Free 25 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 26 * 02111-1307 USA. 27 */ 28 29 #include <errno.h> 30 #include <malloc.h> 31 32 #ifdef USE_HOSTCC /* HOST build */ 33 # include <string.h> 34 # include <assert.h> 35 # include <ctype.h> 36 37 # ifndef debug 38 # ifdef DEBUG 39 # define debug(fmt,args...) printf(fmt ,##args) 40 # else 41 # define debug(fmt,args...) 42 # endif 43 # endif 44 #else /* U-Boot build */ 45 # include <common.h> 46 # include <linux/string.h> 47 # include <linux/ctype.h> 48 #endif 49 50 #ifndef CONFIG_ENV_MIN_ENTRIES /* minimum number of entries */ 51 #define CONFIG_ENV_MIN_ENTRIES 64 52 #endif 53 #ifndef CONFIG_ENV_MAX_ENTRIES /* maximum number of entries */ 54 #define CONFIG_ENV_MAX_ENTRIES 512 55 #endif 56 57 #include "search.h" 58 59 /* 60 * [Aho,Sethi,Ullman] Compilers: Principles, Techniques and Tools, 1986 61 * [Knuth] The Art of Computer Programming, part 3 (6.4) 62 */ 63 64 /* 65 * The reentrant version has no static variables to maintain the state. 66 * Instead the interface of all functions is extended to take an argument 67 * which describes the current status. 68 */ 69 typedef struct _ENTRY { 70 int used; 71 ENTRY entry; 72 } _ENTRY; 73 74 75 /* 76 * hcreate() 77 */ 78 79 /* 80 * For the used double hash method the table size has to be a prime. To 81 * correct the user given table size we need a prime test. This trivial 82 * algorithm is adequate because 83 * a) the code is (most probably) called a few times per program run and 84 * b) the number is small because the table must fit in the core 85 * */ 86 static int isprime(unsigned int number) 87 { 88 /* no even number will be passed */ 89 unsigned int div = 3; 90 91 while (div * div < number && number % div != 0) 92 div += 2; 93 94 return number % div != 0; 95 } 96 97 /* 98 * Before using the hash table we must allocate memory for it. 99 * Test for an existing table are done. We allocate one element 100 * more as the found prime number says. This is done for more effective 101 * indexing as explained in the comment for the hsearch function. 102 * The contents of the table is zeroed, especially the field used 103 * becomes zero. 104 */ 105 106 int hcreate_r(size_t nel, struct hsearch_data *htab) 107 { 108 /* Test for correct arguments. */ 109 if (htab == NULL) { 110 __set_errno(EINVAL); 111 return 0; 112 } 113 114 /* There is still another table active. Return with error. */ 115 if (htab->table != NULL) 116 return 0; 117 118 /* Change nel to the first prime number not smaller as nel. */ 119 nel |= 1; /* make odd */ 120 while (!isprime(nel)) 121 nel += 2; 122 123 htab->size = nel; 124 htab->filled = 0; 125 126 /* allocate memory and zero out */ 127 htab->table = (_ENTRY *) calloc(htab->size + 1, sizeof(_ENTRY)); 128 if (htab->table == NULL) 129 return 0; 130 131 /* everything went alright */ 132 return 1; 133 } 134 135 136 /* 137 * hdestroy() 138 */ 139 140 /* 141 * After using the hash table it has to be destroyed. The used memory can 142 * be freed and the local static variable can be marked as not used. 143 */ 144 145 void hdestroy_r(struct hsearch_data *htab) 146 { 147 int i; 148 149 /* Test for correct arguments. */ 150 if (htab == NULL) { 151 __set_errno(EINVAL); 152 return; 153 } 154 155 /* free used memory */ 156 for (i = 1; i <= htab->size; ++i) { 157 if (htab->table[i].used > 0) { 158 ENTRY *ep = &htab->table[i].entry; 159 160 free((void *)ep->key); 161 free(ep->data); 162 } 163 } 164 free(htab->table); 165 166 /* the sign for an existing table is an value != NULL in htable */ 167 htab->table = NULL; 168 } 169 170 /* 171 * hsearch() 172 */ 173 174 /* 175 * This is the search function. It uses double hashing with open addressing. 176 * The argument item.key has to be a pointer to an zero terminated, most 177 * probably strings of chars. The function for generating a number of the 178 * strings is simple but fast. It can be replaced by a more complex function 179 * like ajw (see [Aho,Sethi,Ullman]) if the needs are shown. 180 * 181 * We use an trick to speed up the lookup. The table is created by hcreate 182 * with one more element available. This enables us to use the index zero 183 * special. This index will never be used because we store the first hash 184 * index in the field used where zero means not used. Every other value 185 * means used. The used field can be used as a first fast comparison for 186 * equality of the stored and the parameter value. This helps to prevent 187 * unnecessary expensive calls of strcmp. 188 * 189 * This implementation differs from the standard library version of 190 * this function in a number of ways: 191 * 192 * - While the standard version does not make any assumptions about 193 * the type of the stored data objects at all, this implementation 194 * works with NUL terminated strings only. 195 * - Instead of storing just pointers to the original objects, we 196 * create local copies so the caller does not need to care about the 197 * data any more. 198 * - The standard implementation does not provide a way to update an 199 * existing entry. This version will create a new entry or update an 200 * existing one when both "action == ENTER" and "item.data != NULL". 201 * - Instead of returning 1 on success, we return the index into the 202 * internal hash table, which is also guaranteed to be positive. 203 * This allows us direct access to the found hash table slot for 204 * example for functions like hdelete(). 205 */ 206 207 /* 208 * hstrstr_r - return index to entry whose key and/or data contains match 209 */ 210 int hstrstr_r(const char *match, int last_idx, ENTRY ** retval, 211 struct hsearch_data *htab) 212 { 213 unsigned int idx; 214 215 for (idx = last_idx + 1; idx < htab->size; ++idx) { 216 if (htab->table[idx].used <= 0) 217 continue; 218 if (strstr(htab->table[idx].entry.key, match) || 219 strstr(htab->table[idx].entry.data, match)) { 220 *retval = &htab->table[idx].entry; 221 return idx; 222 } 223 } 224 225 __set_errno(ESRCH); 226 *retval = NULL; 227 return 0; 228 } 229 230 int hmatch_r(const char *match, int last_idx, ENTRY ** retval, 231 struct hsearch_data *htab) 232 { 233 unsigned int idx; 234 size_t key_len = strlen(match); 235 236 for (idx = last_idx + 1; idx < htab->size; ++idx) { 237 if (htab->table[idx].used <= 0) 238 continue; 239 if (!strncmp(match, htab->table[idx].entry.key, key_len)) { 240 *retval = &htab->table[idx].entry; 241 return idx; 242 } 243 } 244 245 __set_errno(ESRCH); 246 *retval = NULL; 247 return 0; 248 } 249 250 int hsearch_r(ENTRY item, ACTION action, ENTRY ** retval, 251 struct hsearch_data *htab) 252 { 253 unsigned int hval; 254 unsigned int count; 255 unsigned int len = strlen(item.key); 256 unsigned int idx; 257 unsigned int first_deleted = 0; 258 259 /* Compute an value for the given string. Perhaps use a better method. */ 260 hval = len; 261 count = len; 262 while (count-- > 0) { 263 hval <<= 4; 264 hval += item.key[count]; 265 } 266 267 /* 268 * First hash function: 269 * simply take the modul but prevent zero. 270 */ 271 hval %= htab->size; 272 if (hval == 0) 273 ++hval; 274 275 /* The first index tried. */ 276 idx = hval; 277 278 if (htab->table[idx].used) { 279 /* 280 * Further action might be required according to the 281 * action value. 282 */ 283 unsigned hval2; 284 285 if (htab->table[idx].used == -1 286 && !first_deleted) 287 first_deleted = idx; 288 289 if (htab->table[idx].used == hval 290 && strcmp(item.key, htab->table[idx].entry.key) == 0) { 291 /* Overwrite existing value? */ 292 if ((action == ENTER) && (item.data != NULL)) { 293 free(htab->table[idx].entry.data); 294 htab->table[idx].entry.data = 295 strdup(item.data); 296 if (!htab->table[idx].entry.data) { 297 __set_errno(ENOMEM); 298 *retval = NULL; 299 return 0; 300 } 301 } 302 /* return found entry */ 303 *retval = &htab->table[idx].entry; 304 return idx; 305 } 306 307 /* 308 * Second hash function: 309 * as suggested in [Knuth] 310 */ 311 hval2 = 1 + hval % (htab->size - 2); 312 313 do { 314 /* 315 * Because SIZE is prime this guarantees to 316 * step through all available indices. 317 */ 318 if (idx <= hval2) 319 idx = htab->size + idx - hval2; 320 else 321 idx -= hval2; 322 323 /* 324 * If we visited all entries leave the loop 325 * unsuccessfully. 326 */ 327 if (idx == hval) 328 break; 329 330 /* If entry is found use it. */ 331 if ((htab->table[idx].used == hval) 332 && strcmp(item.key, htab->table[idx].entry.key) == 0) { 333 /* Overwrite existing value? */ 334 if ((action == ENTER) && (item.data != NULL)) { 335 free(htab->table[idx].entry.data); 336 htab->table[idx].entry.data = 337 strdup(item.data); 338 if (!htab->table[idx].entry.data) { 339 __set_errno(ENOMEM); 340 *retval = NULL; 341 return 0; 342 } 343 } 344 /* return found entry */ 345 *retval = &htab->table[idx].entry; 346 return idx; 347 } 348 } 349 while (htab->table[idx].used); 350 } 351 352 /* An empty bucket has been found. */ 353 if (action == ENTER) { 354 /* 355 * If table is full and another entry should be 356 * entered return with error. 357 */ 358 if (htab->filled == htab->size) { 359 __set_errno(ENOMEM); 360 *retval = NULL; 361 return 0; 362 } 363 364 /* 365 * Create new entry; 366 * create copies of item.key and item.data 367 */ 368 if (first_deleted) 369 idx = first_deleted; 370 371 htab->table[idx].used = hval; 372 htab->table[idx].entry.key = strdup(item.key); 373 htab->table[idx].entry.data = strdup(item.data); 374 if (!htab->table[idx].entry.key || 375 !htab->table[idx].entry.data) { 376 __set_errno(ENOMEM); 377 *retval = NULL; 378 return 0; 379 } 380 381 ++htab->filled; 382 383 /* return new entry */ 384 *retval = &htab->table[idx].entry; 385 return 1; 386 } 387 388 __set_errno(ESRCH); 389 *retval = NULL; 390 return 0; 391 } 392 393 394 /* 395 * hdelete() 396 */ 397 398 /* 399 * The standard implementation of hsearch(3) does not provide any way 400 * to delete any entries from the hash table. We extend the code to 401 * do that. 402 */ 403 404 int hdelete_r(const char *key, struct hsearch_data *htab) 405 { 406 ENTRY e, *ep; 407 int idx; 408 409 debug("hdelete: DELETE key \"%s\"\n", key); 410 411 e.key = (char *)key; 412 413 if ((idx = hsearch_r(e, FIND, &ep, htab)) == 0) { 414 __set_errno(ESRCH); 415 return 0; /* not found */ 416 } 417 418 /* free used ENTRY */ 419 debug("hdelete: DELETING key \"%s\"\n", key); 420 421 free((void *)ep->key); 422 free(ep->data); 423 htab->table[idx].used = -1; 424 425 --htab->filled; 426 427 return 1; 428 } 429 430 /* 431 * hexport() 432 */ 433 434 /* 435 * Export the data stored in the hash table in linearized form. 436 * 437 * Entries are exported as "name=value" strings, separated by an 438 * arbitrary (non-NUL, of course) separator character. This allows to 439 * use this function both when formatting the U-Boot environment for 440 * external storage (using '\0' as separator), but also when using it 441 * for the "printenv" command to print all variables, simply by using 442 * as '\n" as separator. This can also be used for new features like 443 * exporting the environment data as text file, including the option 444 * for later re-import. 445 * 446 * The entries in the result list will be sorted by ascending key 447 * values. 448 * 449 * If the separator character is different from NUL, then any 450 * separator characters and backslash characters in the values will 451 * be escaped by a preceeding backslash in output. This is needed for 452 * example to enable multi-line values, especially when the output 453 * shall later be parsed (for example, for re-import). 454 * 455 * There are several options how the result buffer is handled: 456 * 457 * *resp size 458 * ----------- 459 * NULL 0 A string of sufficient length will be allocated. 460 * NULL >0 A string of the size given will be 461 * allocated. An error will be returned if the size is 462 * not sufficient. Any unused bytes in the string will 463 * be '\0'-padded. 464 * !NULL 0 The user-supplied buffer will be used. No length 465 * checking will be performed, i. e. it is assumed that 466 * the buffer size will always be big enough. DANGEROUS. 467 * !NULL >0 The user-supplied buffer will be used. An error will 468 * be returned if the size is not sufficient. Any unused 469 * bytes in the string will be '\0'-padded. 470 */ 471 472 static int cmpkey(const void *p1, const void *p2) 473 { 474 ENTRY *e1 = *(ENTRY **) p1; 475 ENTRY *e2 = *(ENTRY **) p2; 476 477 return (strcmp(e1->key, e2->key)); 478 } 479 480 ssize_t hexport_r(struct hsearch_data *htab, const char sep, 481 char **resp, size_t size) 482 { 483 ENTRY *list[htab->size]; 484 char *res, *p; 485 size_t totlen; 486 int i, n; 487 488 /* Test for correct arguments. */ 489 if ((resp == NULL) || (htab == NULL)) { 490 __set_errno(EINVAL); 491 return (-1); 492 } 493 494 debug("EXPORT table = %p, htab.size = %d, htab.filled = %d, size = %d\n", 495 htab, htab->size, htab->filled, size); 496 /* 497 * Pass 1: 498 * search used entries, 499 * save addresses and compute total length 500 */ 501 for (i = 1, n = 0, totlen = 0; i <= htab->size; ++i) { 502 503 if (htab->table[i].used > 0) { 504 ENTRY *ep = &htab->table[i].entry; 505 506 list[n++] = ep; 507 508 totlen += strlen(ep->key) + 2; 509 510 if (sep == '\0') { 511 totlen += strlen(ep->data); 512 } else { /* check if escapes are needed */ 513 char *s = ep->data; 514 515 while (*s) { 516 ++totlen; 517 /* add room for needed escape chars */ 518 if ((*s == sep) || (*s == '\\')) 519 ++totlen; 520 ++s; 521 } 522 } 523 totlen += 2; /* for '=' and 'sep' char */ 524 } 525 } 526 527 #ifdef DEBUG 528 /* Pass 1a: print unsorted list */ 529 printf("Unsorted: n=%d\n", n); 530 for (i = 0; i < n; ++i) { 531 printf("\t%3d: %p ==> %-10s => %s\n", 532 i, list[i], list[i]->key, list[i]->data); 533 } 534 #endif 535 536 /* Sort list by keys */ 537 qsort(list, n, sizeof(ENTRY *), cmpkey); 538 539 /* Check if the user supplied buffer size is sufficient */ 540 if (size) { 541 if (size < totlen + 1) { /* provided buffer too small */ 542 debug("### buffer too small: %d, but need %d\n", 543 size, totlen + 1); 544 __set_errno(ENOMEM); 545 return (-1); 546 } 547 } else { 548 size = totlen + 1; 549 } 550 551 /* Check if the user provided a buffer */ 552 if (*resp) { 553 /* yes; clear it */ 554 res = *resp; 555 memset(res, '\0', size); 556 } else { 557 /* no, allocate and clear one */ 558 *resp = res = calloc(1, size); 559 if (res == NULL) { 560 __set_errno(ENOMEM); 561 return (-1); 562 } 563 } 564 /* 565 * Pass 2: 566 * export sorted list of result data 567 */ 568 for (i = 0, p = res; i < n; ++i) { 569 const char *s; 570 571 s = list[i]->key; 572 while (*s) 573 *p++ = *s++; 574 *p++ = '='; 575 576 s = list[i]->data; 577 578 while (*s) { 579 if ((*s == sep) || (*s == '\\')) 580 *p++ = '\\'; /* escape */ 581 *p++ = *s++; 582 } 583 *p++ = sep; 584 } 585 *p = '\0'; /* terminate result */ 586 587 return size; 588 } 589 590 591 /* 592 * himport() 593 */ 594 595 /* 596 * Import linearized data into hash table. 597 * 598 * This is the inverse function to hexport(): it takes a linear list 599 * of "name=value" pairs and creates hash table entries from it. 600 * 601 * Entries without "value", i. e. consisting of only "name" or 602 * "name=", will cause this entry to be deleted from the hash table. 603 * 604 * The "flag" argument can be used to control the behaviour: when the 605 * H_NOCLEAR bit is set, then an existing hash table will kept, i. e. 606 * new data will be added to an existing hash table; otherwise, old 607 * data will be discarded and a new hash table will be created. 608 * 609 * The separator character for the "name=value" pairs can be selected, 610 * so we both support importing from externally stored environment 611 * data (separated by NUL characters) and from plain text files 612 * (entries separated by newline characters). 613 * 614 * To allow for nicely formatted text input, leading white space 615 * (sequences of SPACE and TAB chars) is ignored, and entries starting 616 * (after removal of any leading white space) with a '#' character are 617 * considered comments and ignored. 618 * 619 * [NOTE: this means that a variable name cannot start with a '#' 620 * character.] 621 * 622 * When using a non-NUL separator character, backslash is used as 623 * escape character in the value part, allowing for example for 624 * multi-line values. 625 * 626 * In theory, arbitrary separator characters can be used, but only 627 * '\0' and '\n' have really been tested. 628 */ 629 630 int himport_r(struct hsearch_data *htab, 631 const char *env, size_t size, const char sep, int flag) 632 { 633 char *data, *sp, *dp, *name, *value; 634 635 /* Test for correct arguments. */ 636 if (htab == NULL) { 637 __set_errno(EINVAL); 638 return 0; 639 } 640 641 /* we allocate new space to make sure we can write to the array */ 642 if ((data = malloc(size)) == NULL) { 643 debug("himport_r: can't malloc %d bytes\n", size); 644 __set_errno(ENOMEM); 645 return 0; 646 } 647 memcpy(data, env, size); 648 dp = data; 649 650 if ((flag & H_NOCLEAR) == 0) { 651 /* Destroy old hash table if one exists */ 652 debug("Destroy Hash Table: %p table = %p\n", htab, 653 htab->table); 654 if (htab->table) 655 hdestroy_r(htab); 656 } 657 658 /* 659 * Create new hash table (if needed). The computation of the hash 660 * table size is based on heuristics: in a sample of some 70+ 661 * existing systems we found an average size of 39+ bytes per entry 662 * in the environment (for the whole key=value pair). Assuming a 663 * size of 8 per entry (= safety factor of ~5) should provide enough 664 * safety margin for any existing environment definitions and still 665 * allow for more than enough dynamic additions. Note that the 666 * "size" argument is supposed to give the maximum enviroment size 667 * (CONFIG_ENV_SIZE). This heuristics will result in 668 * unreasonably large numbers (and thus memory footprint) for 669 * big flash environments (>8,000 entries for 64 KB 670 * envrionment size), so we clip it to a reasonable value. 671 * On the other hand we need to add some more entries for free 672 * space when importing very small buffers. Both boundaries can 673 * be overwritten in the board config file if needed. 674 */ 675 676 if (!htab->table) { 677 int nent = CONFIG_ENV_MIN_ENTRIES + size / 8; 678 679 if (nent > CONFIG_ENV_MAX_ENTRIES) 680 nent = CONFIG_ENV_MAX_ENTRIES; 681 682 debug("Create Hash Table: N=%d\n", nent); 683 684 if (hcreate_r(nent, htab) == 0) { 685 free(data); 686 return 0; 687 } 688 } 689 690 /* Parse environment; allow for '\0' and 'sep' as separators */ 691 do { 692 ENTRY e, *rv; 693 694 /* skip leading white space */ 695 while (isblank(*dp)) 696 ++dp; 697 698 /* skip comment lines */ 699 if (*dp == '#') { 700 while (*dp && (*dp != sep)) 701 ++dp; 702 ++dp; 703 continue; 704 } 705 706 /* parse name */ 707 for (name = dp; *dp != '=' && *dp && *dp != sep; ++dp) 708 ; 709 710 /* deal with "name" and "name=" entries (delete var) */ 711 if (*dp == '\0' || *(dp + 1) == '\0' || 712 *dp == sep || *(dp + 1) == sep) { 713 if (*dp == '=') 714 *dp++ = '\0'; 715 *dp++ = '\0'; /* terminate name */ 716 717 debug("DELETE CANDIDATE: \"%s\"\n", name); 718 719 if (hdelete_r(name, htab) == 0) 720 debug("DELETE ERROR ##############################\n"); 721 722 continue; 723 } 724 *dp++ = '\0'; /* terminate name */ 725 726 /* parse value; deal with escapes */ 727 for (value = sp = dp; *dp && (*dp != sep); ++dp) { 728 if ((*dp == '\\') && *(dp + 1)) 729 ++dp; 730 *sp++ = *dp; 731 } 732 *sp++ = '\0'; /* terminate value */ 733 ++dp; 734 735 /* enter into hash table */ 736 e.key = name; 737 e.data = value; 738 739 hsearch_r(e, ENTER, &rv, htab); 740 if (rv == NULL) { 741 printf("himport_r: can't insert \"%s=%s\" into hash table\n", 742 name, value); 743 return 0; 744 } 745 746 debug("INSERT: table %p, filled %d/%d rv %p ==> name=\"%s\" value=\"%s\"\n", 747 htab, htab->filled, htab->size, 748 rv, name, value); 749 } while ((dp < data + size) && *dp); /* size check needed for text */ 750 /* without '\0' termination */ 751 debug("INSERT: free(data = %p)\n", data); 752 free(data); 753 754 debug("INSERT: done\n"); 755 return 1; /* everything OK */ 756 } 757