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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 #ifdef WITH_FUSE
  80                 if (lte->staging_list.next)
  81                         list_del(&lte->staging_list);
  82 #endif
  83                 switch (lte->resource_location) {
  84                 case RESOURCE_IN_STAGING_FILE:
  85                 case RESOURCE_IN_ATTACHED_BUFFER:
  86                 case RESOURCE_IN_FILE_ON_DISK:
  87                         wimlib_assert(((void*)&lte->file_on_disk ==
  88                                       (void*)&lte->staging_file_name)
  89                                       && ((void*)&lte->file_on_disk ==
  90                                       (void*)&lte->attached_buffer));
  91                         FREE(lte->file_on_disk);
  92                         break;
  93 #ifdef WITH_NTFS_3G
  94                 case RESOURCE_IN_NTFS_VOLUME:
  95                         if (lte->ntfs_loc) {
  96                                 FREE(lte->ntfs_loc->path_utf8);
  97                                 FREE(lte->ntfs_loc->stream_name_utf16);
  98                                 FREE(lte->ntfs_loc);
  99                         }
 100                         break;
 101 #endif
 102                 default:
 103                         break;
 104                 }
 105                 FREE(lte->extracted_file);
 106                 FREE(lte);
 107         }
 108 }
 109
 110 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
 111                                       void *ignore)
 112 {
 113         free_lookup_table_entry(entry);
 114         return 0;
 115 }
 116
 117
 118 void free_lookup_table(struct lookup_table *table)
 119 {
 120         DEBUG2("Freeing lookup table");
 121         if (table) {
 122                 if (table->array) {
 123                         for_lookup_table_entry(table,
 124                                                do_free_lookup_table_entry,
 125                                                NULL);
 126                         FREE(table->array);
 127                 }
 128                 FREE(table);
 129         }
 130 }
 131
 132 /*
 133  * Inserts an entry into the lookup table.
 134  *
 135  * @table:      A pointer to the lookup table.
 136  * @entry:      A pointer to the entry to insert.
 137  */
 138 void lookup_table_insert(struct lookup_table *table,
 139                          struct lookup_table_entry *lte)
 140 {
 141         size_t i = lte->hash_short % table->capacity;
 142         hlist_add_head(&lte->hash_list, &table->array[i]);
 143
 144         /* XXX Make the table grow when too many entries have been inserted. */
 145         table->num_entries++;
 146 }
 147
 148 static void finalize_lte(struct lookup_table_entry *lte)
 149 {
 150         #ifdef WITH_FUSE
 151         if (lte->resource_location == RESOURCE_IN_STAGING_FILE)
 152                 unlink(lte->staging_file_name);
 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 struct lookup_table_entry *
 162 lte_decrement_refcnt(struct lookup_table_entry *lte, struct lookup_table *table)
 163 {
 164         if (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                         {
 172                                 finalize_lte(lte);
 173                                 lte = NULL;
 174                         }
 175                 }
 176         }
 177         return lte;
 178 }
 179
 180 #ifdef WITH_FUSE
 181 struct lookup_table_entry *
 182 lte_decrement_num_opened_fds(struct lookup_table_entry *lte,
 183                              struct lookup_table *table)
 184 {
 185         if (lte) {
 186                 wimlib_assert(lte->num_opened_fds);
 187                 if (--lte->num_opened_fds == 0 && lte->refcnt == 0) {
 188                         lookup_table_unlink(table, lte);
 189                         finalize_lte(lte);
 190                         lte = NULL;
 191                 }
 192         }
 193         return lte;
 194 }
 195 #endif
 196
 197 /*
 198  * Calls a function on all the entries in the lookup table.  Stop early and
 199  * return nonzero if any call to the function returns nonzero.
 200  */
 201 int for_lookup_table_entry(struct lookup_table *table,
 202                            int (*visitor)(struct lookup_table_entry *, void *),
 203                            void *arg)
 204 {
 205         struct lookup_table_entry *lte;
 206         struct hlist_node *pos, *tmp;
 207         int ret;
 208
 209         for (size_t i = 0; i < table->capacity; i++) {
 210                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 211                                           hash_list)
 212                 {
 213                         ret = visitor(lte, arg);
 214                         if (ret != 0)
 215                                 return ret;
 216                 }
 217         }
 218         return 0;
 219 }
 220
 221
 222 /*
 223  * Reads the lookup table from a WIM file.
 224  */
 225 int read_lookup_table(WIMStruct *w)
 226 {
 227         u64    num_entries;
 228         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 229         int    ret;
 230         struct lookup_table *table;
 231         struct lookup_table_entry *cur_entry = NULL, *duplicate_entry;
 232
 233         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 234               w->hdr.lookup_table_res_entry.offset,
 235               w->hdr.lookup_table_res_entry.original_size);
 236
 237         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 238                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 239                                  "lookup table",
 240                                  w->hdr.lookup_table_res_entry.offset);
 241                 return WIMLIB_ERR_READ;
 242         }
 243
 244         num_entries = w->hdr.lookup_table_res_entry.original_size /
 245                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 246         table = new_lookup_table(num_entries * 2 + 1);
 247         if (!table)
 248                 return WIMLIB_ERR_NOMEM;
 249
 250         while (num_entries--) {
 251                 const u8 *p;
 252
 253                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 254                         if (feof(w->fp)) {
 255                                 ERROR("Unexpected EOF in WIM lookup table!");
 256                         } else {
 257                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 258                                                  "table");
 259                         }
 260                         ret = WIMLIB_ERR_READ;
 261                         goto out;
 262                 }
 263                 cur_entry = new_lookup_table_entry();
 264                 if (!cur_entry) {
 265                         ret = WIMLIB_ERR_NOMEM;
 266                         goto out;
 267                 }
 268                 cur_entry->wim = w;
 269                 cur_entry->resource_location = RESOURCE_IN_WIM;
 270
 271                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 272                 p = get_u16(p, &cur_entry->part_number);
 273                 p = get_u32(p, &cur_entry->refcnt);
 274                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 275
 276                 if (cur_entry->part_number != w->hdr.part_number) {
 277                         ERROR("A lookup table entry in part %hu of the WIM "
 278                               "points to part %hu",
 279                               w->hdr.part_number, cur_entry->part_number);
 280                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 281                         goto out_free_cur_entry;
 282
 283                 }
 284
 285                 if (is_zero_hash(cur_entry->hash)) {
 286                         ERROR("The WIM lookup table contains an entry with a "
 287                               "SHA1 message digest of all 0's");
 288                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 289                         goto out_free_cur_entry;
 290                 }
 291
 292                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 293                 if (duplicate_entry) {
 294                         ERROR("The WIM lookup table contains two entries with the "
 295                               "same SHA1 message digest!");
 296                         ERROR("The first entry is:");
 297                         print_lookup_table_entry(duplicate_entry);
 298                         ERROR("The second entry is:");
 299                         print_lookup_table_entry(cur_entry);
 300                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 301                         goto out_free_cur_entry;
 302                 }
 303
 304                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 305                     && (cur_entry->resource_entry.size !=
 306                       cur_entry->resource_entry.original_size))
 307                 {
 308                         ERROR("Found uncompressed resource with original size "
 309                               "not the same as compressed size");
 310                         ERROR("The lookup table entry for the resource is as follows:");
 311                         print_lookup_table_entry(cur_entry);
 312                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 313                         goto out_free_cur_entry;
 314                 }
 315                 lookup_table_insert(table, cur_entry);
 316
 317         }
 318         DEBUG("Done reading lookup table.");
 319         w->lookup_table = table;
 320         return 0;
 321 out_free_cur_entry:
 322         FREE(cur_entry);
 323 out:
 324         free_lookup_table(table);
 325         return ret;
 326 }
 327
 328
 329 /*
 330  * Writes a lookup table entry to the output file.
 331  */
 332 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 333 {
 334         FILE *out;
 335         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 336         u8 *p;
 337
 338         out = __out;
 339
 340         /* Don't write entries that have not had file resources or metadata
 341          * resources written for them. */
 342         if (lte->out_refcnt == 0)
 343                 return 0;
 344
 345         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 346                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 347                       ftello(out), lte->output_resource_entry.original_size);
 348
 349         p = put_resource_entry(buf, &lte->output_resource_entry);
 350         p = put_u16(p, lte->part_number);
 351         p = put_u32(p, lte->out_refcnt);
 352         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 353         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 354                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 355                 return WIMLIB_ERR_WRITE;
 356         }
 357         return 0;
 358 }
 359
 360
 361
 362 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
 363 {
 364         entry->out_refcnt = 0;
 365         return 0;
 366 }
 367
 368 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 369 {
 370         if (!lte) {
 371                 putchar('\n');
 372                 return;
 373         }
 374         printf("Offset            = %"PRIu64" bytes\n",
 375                lte->resource_entry.offset);
 376         printf("Size              = %"PRIu64" bytes\n",
 377                (u64)lte->resource_entry.size);
 378         printf("Original size     = %"PRIu64" bytes\n",
 379                lte->resource_entry.original_size);
 380         printf("Part Number       = %hu\n", lte->part_number);
 381         printf("Reference Count   = %u\n", lte->refcnt);
 382         printf("Hash              = 0x");
 383         print_hash(lte->hash);
 384         putchar('\n');
 385         printf("Flags             = ");
 386         u8 flags = lte->resource_entry.flags;
 387         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 388                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 389         if (flags & WIM_RESHDR_FLAG_FREE)
 390                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 391         if (flags & WIM_RESHDR_FLAG_METADATA)
 392                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 393         if (flags & WIM_RESHDR_FLAG_SPANNED)
 394                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 395         putchar('\n');
 396         switch (lte->resource_location) {
 397         case RESOURCE_IN_WIM:
 398                 if (lte->wim->filename) {
 399                         printf("WIM file          = `%s'\n",
 400                                lte->wim->filename);
 401                 }
 402                 break;
 403         case RESOURCE_IN_FILE_ON_DISK:
 404                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 405                 break;
 406         case RESOURCE_IN_STAGING_FILE:
 407                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 408                 break;
 409         default:
 410                 break;
 411         }
 412         putchar('\n');
 413 }
 414
 415 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 416                                        void *ignore)
 417 {
 418         print_lookup_table_entry(lte);
 419         return 0;
 420 }
 421
 422 /*
 423  * Prints the lookup table of a WIM file.
 424  */
 425 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 426 {
 427         for_lookup_table_entry(w->lookup_table,
 428                                do_print_lookup_table_entry,
 429                                NULL);
 430 }
 431
 432 /*
 433  * Looks up an entry in the lookup table.
 434  */
 435 struct lookup_table_entry *
 436 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 437 {
 438         size_t i;
 439         struct lookup_table_entry *lte;
 440         struct hlist_node *pos;
 441
 442         i = *(size_t*)hash % table->capacity;
 443         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 444                 if (hashes_equal(hash, lte->hash))
 445                         return lte;
 446         return NULL;
 447 }
 448
 449 /*
 450  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 451  * given a path name.
 452  *
 453  * This is only for pre-resolved inodes.
 454  */
 455 int lookup_resource(WIMStruct *w, const char *path,
 456                     int lookup_flags,
 457                     struct dentry **dentry_ret,
 458                     struct lookup_table_entry **lte_ret,
 459                     u16 *stream_idx_ret)
 460 {
 461         struct dentry *dentry;
 462         struct lookup_table_entry *lte;
 463         u16 stream_idx;
 464         const char *stream_name = NULL;
 465         struct inode *inode;
 466         char *p = NULL;
 467
 468         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 469                 stream_name = path_stream_name(path);
 470                 if (stream_name) {
 471                         p = (char*)stream_name - 1;
 472                         *p = '\0';
 473                 }
 474         }
 475
 476         dentry = get_dentry(w, path);
 477         if (p)
 478                 *p = ':';
 479         if (!dentry)
 480                 return -ENOENT;
 481
 482         inode = dentry->inode;
 483
 484         wimlib_assert(inode->resolved);
 485
 486         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 487               && inode_is_directory(inode))
 488                 return -EISDIR;
 489
 490         if (stream_name) {
 491                 struct ads_entry *ads_entry;
 492                 u16 ads_idx;
 493                 ads_entry = inode_get_ads_entry(inode, stream_name,
 494                                                 &ads_idx);
 495                 if (ads_entry) {
 496                         stream_idx = ads_idx + 1;
 497                         lte = ads_entry->lte;
 498                         goto out;
 499                 } else {
 500                         return -ENOENT;
 501                 }
 502         } else {
 503                 lte = inode->lte;
 504                 stream_idx = 0;
 505         }
 506 out:
 507         if (dentry_ret)
 508                 *dentry_ret = dentry;
 509         if (lte_ret)
 510                 *lte_ret = lte;
 511         if (stream_idx_ret)
 512                 *stream_idx_ret = stream_idx;
 513         return 0;
 514 }
 515
 516 static int inode_resolve_ltes(struct inode *inode, struct lookup_table *table)
 517 {
 518         struct lookup_table_entry *lte;
 519
 520         /* Resolve the default file stream */
 521         lte = __lookup_resource(table, inode->hash);
 522         inode->lte = lte;
 523         inode->resolved = true;
 524
 525         /* Resolve the alternate data streams */
 526         for (u16 i = 0; i < inode->num_ads; i++) {
 527                 struct ads_entry *cur_entry = inode->ads_entries[i];
 528
 529                 lte = __lookup_resource(table, cur_entry->hash);
 530                 cur_entry->lte = lte;
 531         }
 532         return 0;
 533 }
 534
 535 /* Resolve a dentry's lookup table entries
 536  *
 537  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 538  * lookup table) with pointers directly to the lookup table entries.  A circular
 539  * linked list of streams sharing the same lookup table entry is created.
 540  *
 541  * This function always succeeds; unresolved lookup table entries are given a
 542  * NULL pointer.
 543  */
 544 int dentry_resolve_ltes(struct dentry *dentry, void *table)
 545 {
 546         if (dentry->inode->resolved)
 547                 return 0;
 548         else
 549                 return inode_resolve_ltes(dentry->inode, table);
 550 }
 551
 552
 553
 554
 555 /* Return the lookup table entry for the unnamed data stream of a inode, or
 556  * NULL if there is none.
 557  *
 558  * You'd think this would be easier than it actually is, since the unnamed data
 559  * stream should be the one referenced from the inode itself.  Alas, if there
 560  * are named data streams, Microsoft's "imagex.exe" program will put the unnamed
 561  * data stream in one of the alternate data streams instead of inside the
 562  * inode.  So we need to check the alternate data streams too.
 563  *
 564  * Also, note that a inode may appear to have than one unnamed stream, but if
 565  * the SHA1 message digest is all 0's then the corresponding stream does not
 566  * really "count" (this is the case for the inode's own file stream when the
 567  * file stream that should be there is actually in one of the alternate stream
 568  * entries.).  This is despite the fact that we may need to extract such a
 569  * missing entry as an empty file or empty named data stream.
 570  */
 571 struct lookup_table_entry *
 572 inode_unnamed_lte(const struct inode *inode,
 573                    const struct lookup_table *table)
 574 {
 575         if (inode->resolved)
 576                 return inode_unnamed_lte_resolved(inode);
 577         else
 578                 return inode_unnamed_lte_unresolved(inode, table);
 579 }
 580