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   1 /*
   2  * lookup_table.c
   3  *
   4  * Lookup table, implemented as a hash table, that maps dentries to file
   5  * resources.
   6  */
   7
   8 /*
   9  * Copyright (C) 2012 Eric Biggers
  10  *
  11  * This file is part of wimlib, a library for working with WIM files.
  12  *
  13  * wimlib is free software; you can redistribute it and/or modify it under the
  14  * terms of the GNU General Public License as published by the Free
  15  * Software Foundation; either version 3 of the License, or (at your option)
  16  * any later version.
  17  *
  18  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  19  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  20  * A PARTICULAR PURPOSE. See the GNU General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  25  */
  26
  27 #include "wimlib_internal.h"
  28 #include "lookup_table.h"
  29 #include "io.h"
  30 #include <errno.h>
  31
  32 #ifdef WITH_FUSE
  33 #include <unistd.h>
  34 #endif
  35
  36 struct lookup_table *new_lookup_table(size_t capacity)
  37 {
  38         struct lookup_table *table;
  39         struct hlist_head *array;
  40
  41         table = MALLOC(sizeof(struct lookup_table));
  42         if (!table)
  43                 goto err;
  44         array = CALLOC(capacity, sizeof(array[0]));
  45         if (!array) {
  46                 FREE(table);
  47                 goto err;
  48         }
  49         table->num_entries = 0;
  50         table->capacity = capacity;
  51         table->array = array;
  52         return table;
  53 err:
  54         ERROR("Failed to allocate memory for lookup table with capacity %zu",
  55               capacity);
  56         return NULL;
  57 }
  58
  59 struct lookup_table_entry *new_lookup_table_entry()
  60 {
  61         struct lookup_table_entry *lte;
  62
  63         lte = CALLOC(1, sizeof(struct lookup_table_entry));
  64         if (!lte) {
  65                 ERROR("Out of memory (tried to allocate %zu bytes for "
  66                       "lookup table entry)",
  67                       sizeof(struct lookup_table_entry));
  68                 return NULL;
  69         }
  70
  71         lte->part_number  = 1;
  72         lte->refcnt       = 1;
  73         return lte;
  74 }
  75
  76 void free_lookup_table_entry(struct lookup_table_entry *lte)
  77 {
  78         if (lte) {
  79                 switch (lte->resource_location) {
  80                 case RESOURCE_IN_STAGING_FILE:
  81                 case RESOURCE_IN_ATTACHED_BUFFER:
  82                 case RESOURCE_IN_FILE_ON_DISK:
  83                         wimlib_assert(((void*)&lte->file_on_disk ==
  84                                       (void*)&lte->staging_file_name)
  85                                       && ((void*)&lte->file_on_disk ==
  86                                       (void*)&lte->attached_buffer));
  87                         FREE(lte->file_on_disk);
  88                         break;
  89 #ifdef WITH_NTFS_3G
  90                 case RESOURCE_IN_NTFS_VOLUME:
  91                         if (lte->ntfs_loc) {
  92                                 FREE(lte->ntfs_loc->path_utf8);
  93                                 FREE(lte->ntfs_loc->stream_name_utf16);
  94                                 FREE(lte->ntfs_loc);
  95                         }
  96                         break;
  97 #endif
  98                 default:
  99                         break;
 100                 }
 101                 FREE(lte->extracted_file);
 102                 FREE(lte);
 103         }
 104 }
 105
 106 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
 107                                       void *ignore)
 108 {
 109         free_lookup_table_entry(entry);
 110         return 0;
 111 }
 112
 113
 114 void free_lookup_table(struct lookup_table *table)
 115 {
 116         DEBUG2("Freeing lookup table");
 117         if (table) {
 118                 if (table->array) {
 119                         for_lookup_table_entry(table,
 120                                                do_free_lookup_table_entry,
 121                                                NULL);
 122                         FREE(table->array);
 123                 }
 124                 FREE(table);
 125         }
 126 }
 127
 128 /*
 129  * Inserts an entry into the lookup table.
 130  *
 131  * @table:      A pointer to the lookup table.
 132  * @entry:      A pointer to the entry to insert.
 133  */
 134 void lookup_table_insert(struct lookup_table *table,
 135                          struct lookup_table_entry *lte)
 136 {
 137         size_t i = lte->hash_short % table->capacity;
 138         hlist_add_head(&lte->hash_list, &table->array[i]);
 139
 140         /* XXX Make the table grow when too many entries have been inserted. */
 141         table->num_entries++;
 142 }
 143
 144 static void finalize_lte(struct lookup_table_entry *lte)
 145 {
 146         #ifdef WITH_FUSE
 147         if (lte->resource_location == RESOURCE_IN_STAGING_FILE) {
 148                 unlink(lte->staging_file_name);
 149                 wimlib_assert(lte->staging_list.next);
 150                 wimlib_assert(lte->staging_list.prev);
 151                 list_del(&lte->staging_list);
 152         }
 153         #endif
 154         free_lookup_table_entry(lte);
 155 }
 156
 157 /* Decrements the reference count for the lookup table entry @lte.  If its
 158  * reference count reaches 0, it is unlinked from the lookup table.  If,
 159  * furthermore, the entry has no opened file descriptors associated with it, the
 160  * entry is freed.  */
 161 void lte_decrement_refcnt(struct lookup_table_entry *lte,
 162                           struct lookup_table *table)
 163 {
 164         wimlib_assert(lte);
 165         wimlib_assert(lte->refcnt);
 166         if (--lte->refcnt == 0) {
 167                 lookup_table_unlink(table, lte);
 168         #ifdef WITH_FUSE
 169                 if (lte->num_opened_fds == 0)
 170         #endif
 171                         finalize_lte(lte);
 172         }
 173 }
 174
 175 #ifdef WITH_FUSE
 176 void lte_decrement_num_opened_fds(struct lookup_table_entry *lte,
 177                                   struct lookup_table *table)
 178 {
 179         wimlib_assert(lte);
 180         wimlib_assert(lte->num_opened_fds);
 181         if (--lte->num_opened_fds == 0 && lte->refcnt == 0)
 182                 finalize_lte(lte);
 183 }
 184 #endif
 185
 186 /*
 187  * Calls a function on all the entries in the lookup table.  Stop early and
 188  * return nonzero if any call to the function returns nonzero.
 189  */
 190 int for_lookup_table_entry(struct lookup_table *table,
 191                            int (*visitor)(struct lookup_table_entry *, void *),
 192                            void *arg)
 193 {
 194         struct lookup_table_entry *lte;
 195         struct hlist_node *pos, *tmp;
 196         int ret;
 197
 198         for (size_t i = 0; i < table->capacity; i++) {
 199                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 200                                           hash_list)
 201                 {
 202                         ret = visitor(lte, arg);
 203                         if (ret != 0)
 204                                 return ret;
 205                 }
 206         }
 207         return 0;
 208 }
 209
 210
 211 /*
 212  * Reads the lookup table from a WIM file.
 213  */
 214 int read_lookup_table(WIMStruct *w)
 215 {
 216         u64    num_entries;
 217         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 218         int    ret;
 219         struct lookup_table *table;
 220         struct lookup_table_entry *cur_entry = NULL, *duplicate_entry;
 221
 222         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 223               w->hdr.lookup_table_res_entry.offset,
 224               w->hdr.lookup_table_res_entry.original_size);
 225
 226         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 227                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 228                                  "lookup table",
 229                                  w->hdr.lookup_table_res_entry.offset);
 230                 return WIMLIB_ERR_READ;
 231         }
 232
 233         num_entries = w->hdr.lookup_table_res_entry.original_size /
 234                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 235         table = new_lookup_table(num_entries * 2 + 1);
 236         if (!table)
 237                 return WIMLIB_ERR_NOMEM;
 238
 239         while (num_entries--) {
 240                 const u8 *p;
 241
 242                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 243                         if (feof(w->fp)) {
 244                                 ERROR("Unexpected EOF in WIM lookup table!");
 245                         } else {
 246                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 247                                                  "table");
 248                         }
 249                         ret = WIMLIB_ERR_READ;
 250                         goto out;
 251                 }
 252                 cur_entry = new_lookup_table_entry();
 253                 if (!cur_entry) {
 254                         ret = WIMLIB_ERR_NOMEM;
 255                         goto out;
 256                 }
 257                 cur_entry->wim = w;
 258                 cur_entry->resource_location = RESOURCE_IN_WIM;
 259
 260                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 261                 p = get_u16(p, &cur_entry->part_number);
 262                 p = get_u32(p, &cur_entry->refcnt);
 263                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 264
 265                 if (cur_entry->part_number != w->hdr.part_number) {
 266                         ERROR("A lookup table entry in part %hu of the WIM "
 267                               "points to part %hu",
 268                               w->hdr.part_number, cur_entry->part_number);
 269                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 270                         goto out_free_cur_entry;
 271
 272                 }
 273
 274                 if (is_zero_hash(cur_entry->hash)) {
 275                         ERROR("The WIM lookup table contains an entry with a "
 276                               "SHA1 message digest of all 0's");
 277                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 278                         goto out_free_cur_entry;
 279                 }
 280
 281                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 282                 if (duplicate_entry) {
 283                         ERROR("The WIM lookup table contains two entries with the "
 284                               "same SHA1 message digest!");
 285                         ERROR("The first entry is:");
 286                         print_lookup_table_entry(duplicate_entry);
 287                         ERROR("The second entry is:");
 288                         print_lookup_table_entry(cur_entry);
 289                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 290                         goto out_free_cur_entry;
 291                 }
 292
 293                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 294                     && (cur_entry->resource_entry.size !=
 295                       cur_entry->resource_entry.original_size))
 296                 {
 297                         ERROR("Found uncompressed resource with original size "
 298                               "not the same as compressed size");
 299                         ERROR("The lookup table entry for the resource is as follows:");
 300                         print_lookup_table_entry(cur_entry);
 301                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 302                         goto out_free_cur_entry;
 303                 }
 304                 lookup_table_insert(table, cur_entry);
 305
 306         }
 307         DEBUG("Done reading lookup table.");
 308         w->lookup_table = table;
 309         return 0;
 310 out_free_cur_entry:
 311         FREE(cur_entry);
 312 out:
 313         free_lookup_table(table);
 314         return ret;
 315 }
 316
 317
 318 /*
 319  * Writes a lookup table entry to the output file.
 320  */
 321 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 322 {
 323         FILE *out;
 324         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 325         u8 *p;
 326
 327         out = __out;
 328
 329         /* Don't write entries that have not had file resources or metadata
 330          * resources written for them. */
 331         if (lte->out_refcnt == 0)
 332                 return 0;
 333
 334         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 335                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 336                       ftello(out), lte->output_resource_entry.original_size);
 337
 338         p = put_resource_entry(buf, &lte->output_resource_entry);
 339         p = put_u16(p, lte->part_number);
 340         p = put_u32(p, lte->out_refcnt);
 341         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 342         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 343                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 344                 return WIMLIB_ERR_WRITE;
 345         }
 346         return 0;
 347 }
 348
 349
 350 int lte_zero_real_refcnt(struct lookup_table_entry *lte, void *ignore)
 351 {
 352         lte->real_refcnt = 0;
 353         return 0;
 354 }
 355
 356 int lte_zero_out_refcnt(struct lookup_table_entry *lte, void *ignore)
 357 {
 358         lte->out_refcnt = 0;
 359         return 0;
 360 }
 361
 362 int lte_free_extracted_file(struct lookup_table_entry *lte, void *ignone)
 363 {
 364         FREE(lte->extracted_file);
 365         lte->extracted_file = NULL;
 366         return 0;
 367 }
 368
 369 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 370 {
 371         if (!lte) {
 372                 putchar('\n');
 373                 return;
 374         }
 375         printf("Offset            = %"PRIu64" bytes\n",
 376                lte->resource_entry.offset);
 377         printf("Size              = %"PRIu64" bytes\n",
 378                (u64)lte->resource_entry.size);
 379         printf("Original size     = %"PRIu64" bytes\n",
 380                lte->resource_entry.original_size);
 381         printf("Part Number       = %hu\n", lte->part_number);
 382         printf("Reference Count   = %u\n", lte->refcnt);
 383         printf("Hash              = 0x");
 384         print_hash(lte->hash);
 385         putchar('\n');
 386         printf("Flags             = ");
 387         u8 flags = lte->resource_entry.flags;
 388         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 389                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 390         if (flags & WIM_RESHDR_FLAG_FREE)
 391                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 392         if (flags & WIM_RESHDR_FLAG_METADATA)
 393                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 394         if (flags & WIM_RESHDR_FLAG_SPANNED)
 395                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 396         putchar('\n');
 397         switch (lte->resource_location) {
 398         case RESOURCE_IN_WIM:
 399                 if (lte->wim->filename) {
 400                         printf("WIM file          = `%s'\n",
 401                                lte->wim->filename);
 402                 }
 403                 break;
 404         case RESOURCE_IN_FILE_ON_DISK:
 405                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 406                 break;
 407         case RESOURCE_IN_STAGING_FILE:
 408                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 409                 break;
 410         default:
 411                 break;
 412         }
 413         putchar('\n');
 414 }
 415
 416 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 417                                        void *ignore)
 418 {
 419         print_lookup_table_entry(lte);
 420         return 0;
 421 }
 422
 423 /*
 424  * Prints the lookup table of a WIM file.
 425  */
 426 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 427 {
 428         for_lookup_table_entry(w->lookup_table,
 429                                do_print_lookup_table_entry,
 430                                NULL);
 431 }
 432
 433 /*
 434  * Looks up an entry in the lookup table.
 435  */
 436 struct lookup_table_entry *
 437 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 438 {
 439         size_t i;
 440         struct lookup_table_entry *lte;
 441         struct hlist_node *pos;
 442
 443         wimlib_assert(table);
 444
 445         i = *(size_t*)hash % table->capacity;
 446         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 447                 if (hashes_equal(hash, lte->hash))
 448                         return lte;
 449         return NULL;
 450 }
 451
 452 #ifdef WITH_FUSE
 453 /*
 454  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 455  * given a path name.
 456  *
 457  * This is only for pre-resolved inodes.
 458  */
 459 int lookup_resource(WIMStruct *w, const char *path,
 460                     int lookup_flags,
 461                     struct dentry **dentry_ret,
 462                     struct lookup_table_entry **lte_ret,
 463                     u16 *stream_idx_ret)
 464 {
 465         struct dentry *dentry;
 466         struct lookup_table_entry *lte;
 467         u16 stream_idx;
 468         const char *stream_name = NULL;
 469         struct inode *inode;
 470         char *p = NULL;
 471
 472         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 473                 stream_name = path_stream_name(path);
 474                 if (stream_name) {
 475                         p = (char*)stream_name - 1;
 476                         *p = '\0';
 477                 }
 478         }
 479
 480         dentry = get_dentry(w, path);
 481         if (p)
 482                 *p = ':';
 483         if (!dentry)
 484                 return -ENOENT;
 485
 486         inode = dentry->d_inode;
 487
 488         wimlib_assert(inode->resolved);
 489
 490         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 491               && inode_is_directory(inode))
 492                 return -EISDIR;
 493
 494         if (stream_name) {
 495                 struct ads_entry *ads_entry;
 496                 u16 ads_idx;
 497                 ads_entry = inode_get_ads_entry(inode, stream_name,
 498                                                 &ads_idx);
 499                 if (ads_entry) {
 500                         stream_idx = ads_idx + 1;
 501                         lte = ads_entry->lte;
 502                         goto out;
 503                 } else {
 504                         return -ENOENT;
 505                 }
 506         } else {
 507                 lte = inode->lte;
 508                 stream_idx = 0;
 509         }
 510 out:
 511         if (dentry_ret)
 512                 *dentry_ret = dentry;
 513         if (lte_ret)
 514                 *lte_ret = lte;
 515         if (stream_idx_ret)
 516                 *stream_idx_ret = stream_idx;
 517         return 0;
 518 }
 519 #endif
 520
 521 static void inode_resolve_ltes(struct inode *inode, struct lookup_table *table)
 522 {
 523         struct lookup_table_entry *lte;
 524
 525         /* Resolve the default file stream */
 526         lte = __lookup_resource(table, inode->hash);
 527         inode->lte = lte;
 528         inode->resolved = true;
 529
 530         /* Resolve the alternate data streams */
 531         for (u16 i = 0; i < inode->num_ads; i++) {
 532                 struct ads_entry *cur_entry = &inode->ads_entries[i];
 533                 lte = __lookup_resource(table, cur_entry->hash);
 534                 cur_entry->lte = lte;
 535         }
 536 }
 537
 538 /* Resolve a dentry's lookup table entries
 539  *
 540  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 541  * lookup table) with pointers directly to the lookup table entries.  A circular
 542  * linked list of streams sharing the same lookup table entry is created.
 543  *
 544  * This function always succeeds; unresolved lookup table entries are given a
 545  * NULL pointer.
 546  */
 547 int dentry_resolve_ltes(struct dentry *dentry, void *table)
 548 {
 549         if (!dentry->d_inode->resolved)
 550                 inode_resolve_ltes(dentry->d_inode, table);
 551         return 0;
 552 }
 553
 554 /* Return the lookup table entry for the unnamed data stream of an inode, or
 555  * NULL if there is none.
 556  *
 557  * You'd think this would be easier than it actually is, since the unnamed data
 558  * stream should be the one referenced from the inode itself.  Alas, if there
 559  * are named data streams, Microsoft's "imagex.exe" program will put the unnamed
 560  * data stream in one of the alternate data streams instead of inside the WIM
 561  * dentry itself.  So we need to check the alternate data streams too.
 562  *
 563  * Also, note that a dentry may appear to have than one unnamed stream, but if
 564  * the SHA1 message digest is all 0's then the corresponding stream does not
 565  * really "count" (this is the case for the inode's own file stream when the
 566  * file stream that should be there is actually in one of the alternate stream
 567  * entries.).  This is despite the fact that we may need to extract such a
 568  * missing entry as an empty file or empty named data stream.
 569  */
 570 struct lookup_table_entry *
 571 inode_unnamed_lte(const struct inode *inode,
 572                    const struct lookup_table *table)
 573 {
 574         if (inode->resolved)
 575                 return inode_unnamed_lte_resolved(inode);
 576         else
 577                 return inode_unnamed_lte_unresolved(inode, table);
 578 }
 579