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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 Lesser General Public License as published by the Free
  15  * Software Foundation; either version 2.1 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 Lesser General Public License for more
  21  * details.
  22  *
  23  * You should have received a copy of the GNU Lesser 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 struct lookup_table *new_lookup_table(size_t capacity)
  33 {
  34         struct lookup_table *table;
  35         struct hlist_head *array;
  36
  37         table = MALLOC(sizeof(struct lookup_table));
  38         if (!table)
  39                 goto err;
  40         array = CALLOC(capacity, sizeof(array[0]));
  41         if (!array) {
  42                 FREE(table);
  43                 goto err;
  44         }
  45         table->num_entries = 0;
  46         table->capacity = capacity;
  47         table->array = array;
  48         return table;
  49 err:
  50         ERROR("Failed to allocate memory for lookup table with capacity %zu",
  51               capacity);
  52         return NULL;
  53 }
  54
  55 struct lookup_table_entry *new_lookup_table_entry()
  56 {
  57         struct lookup_table_entry *lte;
  58
  59         lte = CALLOC(1, sizeof(struct lookup_table_entry));
  60         if (!lte) {
  61                 ERROR("Out of memory (tried to allocate %zu bytes for "
  62                       "lookup table entry)",
  63                       sizeof(struct lookup_table_entry));
  64                 return NULL;
  65         }
  66
  67         lte->part_number  = 1;
  68         lte->refcnt       = 1;
  69         INIT_LIST_HEAD(&lte->lte_group_list);
  70         return lte;
  71 }
  72
  73 void free_lookup_table_entry(struct lookup_table_entry *lte)
  74 {
  75         if (lte) {
  76 #ifdef WITH_FUSE
  77                 if (lte->staging_list.next)
  78                         list_del(&lte->staging_list);
  79 #endif
  80                 switch (lte->resource_location) {
  81                 case RESOURCE_IN_STAGING_FILE:
  82                 case RESOURCE_IN_ATTACHED_BUFFER:
  83                 case RESOURCE_IN_FILE_ON_DISK:
  84                         wimlib_assert(&lte->file_on_disk ==
  85                                       &lte->staging_file_name ==
  86                                       &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);
 102         }
 103 }
 104
 105 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
 106                                       void *ignore)
 107 {
 108         free_lookup_table_entry(entry);
 109         return 0;
 110 }
 111
 112
 113 void free_lookup_table(struct lookup_table *table)
 114 {
 115         DEBUG("Freeing lookup table");
 116         if (table) {
 117                 if (table->array) {
 118                         for_lookup_table_entry(table,
 119                                                do_free_lookup_table_entry,
 120                                                NULL);
 121                         FREE(table->array);
 122                 }
 123                 FREE(table);
 124         }
 125 }
 126
 127 /*
 128  * Inserts an entry into the lookup table.
 129  *
 130  * @table:      A pointer to the lookup table.
 131  * @entry:      A pointer to the entry to insert.
 132  */
 133 void lookup_table_insert(struct lookup_table *table,
 134                          struct lookup_table_entry *lte)
 135 {
 136         size_t i = lte->hash_short % table->capacity;
 137         hlist_add_head(&lte->hash_list, &table->array[i]);
 138
 139         /* XXX Make the table grow when too many entries have been inserted. */
 140         table->num_entries++;
 141 }
 142
 143
 144
 145 /* Decrements the reference count for the lookup table entry @lte.  If its
 146  * reference count reaches 0, it is unlinked from the lookup table.  If,
 147  * furthermore, the entry has no opened file descriptors associated with it, the
 148  * entry is freed.  */
 149 struct lookup_table_entry *
 150 lte_decrement_refcnt(struct lookup_table_entry *lte, struct lookup_table *table)
 151 {
 152         if (lte) {
 153                 wimlib_assert(lte->refcnt);
 154                 if (--lte->refcnt == 0) {
 155                         lookup_table_unlink(table, lte);
 156                 #ifdef WITH_FUSE
 157                         if (lte->num_opened_fds == 0)
 158                 #endif
 159                         {
 160                                 free_lookup_table_entry(lte);
 161                                 lte = NULL;
 162                         }
 163                 }
 164         }
 165         return lte;
 166 }
 167
 168 /*
 169  * Calls a function on all the entries in the lookup table.  Stop early and
 170  * return nonzero if any call to the function returns nonzero.
 171  */
 172 int for_lookup_table_entry(struct lookup_table *table,
 173                            int (*visitor)(struct lookup_table_entry *, void *),
 174                            void *arg)
 175 {
 176         struct lookup_table_entry *lte;
 177         struct hlist_node *pos, *tmp;
 178         int ret;
 179
 180         for (size_t i = 0; i < table->capacity; i++) {
 181                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 182                                           hash_list)
 183                 {
 184                         ret = visitor(lte, arg);
 185                         if (ret != 0)
 186                                 return ret;
 187                 }
 188         }
 189         return 0;
 190 }
 191
 192
 193 /*
 194  * Reads the lookup table from a WIM file.
 195  */
 196 int read_lookup_table(WIMStruct *w)
 197 {
 198         u64    num_entries;
 199         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 200         int    ret;
 201         struct lookup_table *table;
 202
 203         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 204               w->hdr.lookup_table_res_entry.offset,
 205               w->hdr.lookup_table_res_entry.original_size);
 206
 207         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 208                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 209                                  "lookup table",
 210                                  w->hdr.lookup_table_res_entry.offset);
 211                 return WIMLIB_ERR_READ;
 212         }
 213
 214         num_entries = w->hdr.lookup_table_res_entry.original_size /
 215                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 216         table = new_lookup_table(num_entries * 2 + 1);
 217         if (!table)
 218                 return WIMLIB_ERR_NOMEM;
 219
 220         while (num_entries--) {
 221                 const u8 *p;
 222                 struct lookup_table_entry *cur_entry, *duplicate_entry;
 223
 224                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 225                         if (feof(w->fp)) {
 226                                 ERROR("Unexpected EOF in WIM lookup table!");
 227                         } else {
 228                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 229                                                  "table");
 230                         }
 231                         ret = WIMLIB_ERR_READ;
 232                         goto out;
 233                 }
 234                 cur_entry = new_lookup_table_entry();
 235                 if (!cur_entry) {
 236                         ret = WIMLIB_ERR_NOMEM;
 237                         goto out;
 238                 }
 239                 cur_entry->wim = w;
 240                 cur_entry->resource_location = RESOURCE_IN_WIM;
 241
 242                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 243                 p = get_u16(p, &cur_entry->part_number);
 244                 p = get_u32(p, &cur_entry->refcnt);
 245                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 246
 247                 if (is_zero_hash(cur_entry->hash)) {
 248                         ERROR("The WIM lookup table contains an entry with a "
 249                               "SHA1 message digest of all 0's");
 250                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 251                         FREE(cur_entry);
 252                         goto out;
 253                 }
 254
 255                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 256                 if (duplicate_entry) {
 257                         ERROR("The WIM lookup table contains two entries with the "
 258                               "same SHA1 message digest!");
 259                         ERROR("The first entry is:");
 260                         print_lookup_table_entry(duplicate_entry);
 261                         ERROR("The second entry is:");
 262                         print_lookup_table_entry(cur_entry);
 263                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 264                         FREE(cur_entry);
 265                         goto out;
 266                 }
 267                 lookup_table_insert(table, cur_entry);
 268
 269                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 270                     && (cur_entry->resource_entry.size !=
 271                       cur_entry->resource_entry.original_size))
 272                 {
 273                         ERROR("Found uncompressed resource with original size "
 274                               "not the same as compressed size");
 275                         ERROR("The lookup table entry for the resource is as follows:");
 276                         print_lookup_table_entry(cur_entry);
 277                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 278                         goto out;
 279                 }
 280         }
 281         DEBUG("Done reading lookup table.");
 282         w->lookup_table = table;
 283         return 0;
 284 out:
 285         free_lookup_table(table);
 286         return ret;
 287 }
 288
 289
 290 /*
 291  * Writes a lookup table entry to the output file.
 292  */
 293 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 294 {
 295         FILE *out;
 296         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 297         u8 *p;
 298
 299         out = __out;
 300
 301         /* Don't write entries that have not had file resources or metadata
 302          * resources written for them. */
 303         if (lte->out_refcnt == 0)
 304                 return 0;
 305
 306         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 307                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 308                       ftello(out), lte->output_resource_entry.original_size);
 309
 310         p = put_resource_entry(buf, &lte->output_resource_entry);
 311         p = put_u16(p, lte->part_number);
 312         p = put_u32(p, lte->out_refcnt);
 313         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 314         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 315                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 316                 return WIMLIB_ERR_WRITE;
 317         }
 318         return 0;
 319 }
 320
 321
 322
 323 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
 324 {
 325         entry->out_refcnt = 0;
 326         return 0;
 327 }
 328
 329 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 330 {
 331         if (!lte) {
 332                 putchar('\n');
 333                 return;
 334         }
 335         printf("Offset            = %"PRIu64" bytes\n",
 336                lte->resource_entry.offset);
 337         printf("Size              = %"PRIu64" bytes\n",
 338                (u64)lte->resource_entry.size);
 339         printf("Original size     = %"PRIu64" bytes\n",
 340                lte->resource_entry.original_size);
 341         printf("Part Number       = %hu\n", lte->part_number);
 342         printf("Reference Count   = %u\n", lte->refcnt);
 343         printf("Hash              = 0x");
 344         print_hash(lte->hash);
 345         putchar('\n');
 346         printf("Flags             = ");
 347         u8 flags = lte->resource_entry.flags;
 348         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 349                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 350         if (flags & WIM_RESHDR_FLAG_FREE)
 351                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 352         if (flags & WIM_RESHDR_FLAG_METADATA)
 353                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 354         if (flags & WIM_RESHDR_FLAG_SPANNED)
 355                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 356         putchar('\n');
 357         switch (lte->resource_location) {
 358         case RESOURCE_IN_WIM:
 359                 if (lte->wim->filename) {
 360                         printf("WIM file          = `%s'\n",
 361                                lte->wim->filename);
 362                 }
 363                 break;
 364         case RESOURCE_IN_FILE_ON_DISK:
 365                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 366                 break;
 367         case RESOURCE_IN_STAGING_FILE:
 368                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 369                 break;
 370         default:
 371                 break;
 372         }
 373         putchar('\n');
 374 }
 375
 376 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 377                                        void *ignore)
 378 {
 379         print_lookup_table_entry(lte);
 380         return 0;
 381 }
 382
 383 /*
 384  * Prints the lookup table of a WIM file.
 385  */
 386 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 387 {
 388         for_lookup_table_entry(w->lookup_table,
 389                                do_print_lookup_table_entry,
 390                                NULL);
 391 }
 392
 393 /*
 394  * Looks up an entry in the lookup table.
 395  */
 396 struct lookup_table_entry *
 397 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 398 {
 399         size_t i;
 400         struct lookup_table_entry *lte;
 401         struct hlist_node *pos;
 402
 403         i = *(size_t*)hash % table->capacity;
 404         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 405                 if (hashes_equal(hash, lte->hash))
 406                         return lte;
 407         return NULL;
 408 }
 409
 410 /*
 411  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 412  * given a path name.
 413  *
 414  * This is only for pre-resolved dentries.
 415  */
 416 int lookup_resource(WIMStruct *w, const char *path,
 417                     int lookup_flags,
 418                     struct dentry **dentry_ret,
 419                     struct lookup_table_entry **lte_ret,
 420                     unsigned *stream_idx_ret)
 421 {
 422         struct dentry *dentry;
 423         struct lookup_table_entry *lte;
 424         unsigned stream_idx;
 425         const char *stream_name = NULL;
 426         char *p = NULL;
 427
 428         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 429                 stream_name = path_stream_name(path);
 430                 if (stream_name) {
 431                         p = (char*)stream_name - 1;
 432                         *p = '\0';
 433                 }
 434         }
 435
 436         dentry = get_dentry(w, path);
 437         if (p)
 438                 *p = ':';
 439         if (!dentry)
 440                 return -ENOENT;
 441
 442         wimlib_assert(dentry->resolved);
 443
 444         lte = dentry->lte;
 445         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 446               && dentry_is_directory(dentry))
 447                 return -EISDIR;
 448         stream_idx = 0;
 449         if (stream_name) {
 450                 size_t stream_name_len = strlen(stream_name);
 451                 for (u16 i = 0; i < dentry->num_ads; i++) {
 452                         if (ads_entry_has_name(&dentry->ads_entries[i],
 453                                                stream_name,
 454                                                stream_name_len))
 455                         {
 456                                 stream_idx = i + 1;
 457                                 lte = dentry->ads_entries[i].lte;
 458                                 goto out;
 459                         }
 460                 }
 461                 return -ENOENT;
 462         }
 463 out:
 464         if (dentry_ret)
 465                 *dentry_ret = dentry;
 466         if (lte_ret)
 467                 *lte_ret = lte;
 468         if (stream_idx_ret)
 469                 *stream_idx_ret = stream_idx;
 470         return 0;
 471 }
 472
 473 /* Resolve a dentry's lookup table entries
 474  *
 475  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 476  * lookup table) with pointers directly to the lookup table entries.  A circular
 477  * linked list of streams sharing the same lookup table entry is created.
 478  *
 479  * This function always succeeds; unresolved lookup table entries are given a
 480  * NULL pointer.
 481  */
 482 int dentry_resolve_ltes(struct dentry *dentry, void *__table)
 483 {
 484         struct lookup_table *table = __table;
 485         struct lookup_table_entry *lte;
 486
 487         if (dentry->resolved)
 488                 return 0;
 489
 490         /* Resolve the default file stream */
 491         lte = __lookup_resource(table, dentry->hash);
 492         if (lte)
 493                 list_add(&dentry->lte_group_list.list, &lte->lte_group_list);
 494         else
 495                 INIT_LIST_HEAD(&dentry->lte_group_list.list);
 496         dentry->lte = lte;
 497         dentry->lte_group_list.type = STREAM_TYPE_NORMAL;
 498         dentry->resolved = true;
 499
 500         /* Resolve the alternate data streams */
 501         if (dentry->ads_entries_status != ADS_ENTRIES_USER) {
 502                 for (u16 i = 0; i < dentry->num_ads; i++) {
 503                         struct ads_entry *cur_entry = &dentry->ads_entries[i];
 504
 505                         lte = __lookup_resource(table, cur_entry->hash);
 506                         if (lte)
 507                                 list_add(&cur_entry->lte_group_list.list,
 508                                          &lte->lte_group_list);
 509                         else
 510                                 INIT_LIST_HEAD(&cur_entry->lte_group_list.list);
 511                         cur_entry->lte = lte;
 512                         cur_entry->lte_group_list.type = STREAM_TYPE_ADS;
 513                 }
 514         }
 515         return 0;
 516 }
 517
 518 /* Return the lookup table entry for the unnamed data stream of a dentry, or
 519  * NULL if there is none.
 520  *
 521  * You'd think this would be easier than it actually is, since the unnamed data
 522  * stream should be the one referenced from the dentry itself.  Alas, if there
 523  * are named data streams, Microsoft's "imagex.exe" program will put the unnamed
 524  * data stream in one of the alternate data streams instead of inside the
 525  * dentry.  So we need to check the alternate data streams too.
 526  *
 527  * Also, note that a dentry may appear to have than one unnamed stream, but if
 528  * the SHA1 message digest is all 0's then the corresponding stream does not
 529  * really "count" (this is the case for the dentry's own file stream when the
 530  * file stream that should be there is actually in one of the alternate stream
 531  * entries.).  This is despite the fact that we may need to extract such a
 532  * missing entry as an empty file or empty named data stream.
 533  */
 534 struct lookup_table_entry *
 535 dentry_unnamed_lte(const struct dentry *dentry,
 536                    const struct lookup_table *table)
 537 {
 538         if (dentry->resolved)
 539                 return dentry_unnamed_lte_resolved(dentry);
 540         else
 541                 return dentry_unnamed_lte_unresolved(dentry, table);
 542 }
 543