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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 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(((void*)&lte->file_on_disk ==
  85                                       (void*)&lte->staging_file_name)
  86                                       && ((void*)&lte->file_on_disk ==
  87                                       (void*)&lte->attached_buffer));
  88                         FREE(lte->file_on_disk);
  89                         break;
  90 #ifdef WITH_NTFS_3G
  91                 case RESOURCE_IN_NTFS_VOLUME:
  92                         if (lte->ntfs_loc) {
  93                                 FREE(lte->ntfs_loc->path_utf8);
  94                                 FREE(lte->ntfs_loc->stream_name_utf16);
  95                                 FREE(lte->ntfs_loc);
  96                         }
  97                         break;
  98 #endif
  99                 default:
 100                         break;
 101                 }
 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
 145
 146 /* Decrements the reference count for the lookup table entry @lte.  If its
 147  * reference count reaches 0, it is unlinked from the lookup table.  If,
 148  * furthermore, the entry has no opened file descriptors associated with it, the
 149  * entry is freed.  */
 150 struct lookup_table_entry *
 151 lte_decrement_refcnt(struct lookup_table_entry *lte, struct lookup_table *table)
 152 {
 153         if (lte) {
 154                 wimlib_assert(lte->refcnt);
 155                 if (--lte->refcnt == 0) {
 156                         lookup_table_unlink(table, lte);
 157                 #ifdef WITH_FUSE
 158                         if (lte->num_opened_fds == 0)
 159                 #endif
 160                         {
 161                                 free_lookup_table_entry(lte);
 162                                 lte = NULL;
 163                         }
 164                 }
 165         }
 166         return lte;
 167 }
 168
 169 /*
 170  * Calls a function on all the entries in the lookup table.  Stop early and
 171  * return nonzero if any call to the function returns nonzero.
 172  */
 173 int for_lookup_table_entry(struct lookup_table *table,
 174                            int (*visitor)(struct lookup_table_entry *, void *),
 175                            void *arg)
 176 {
 177         struct lookup_table_entry *lte;
 178         struct hlist_node *pos, *tmp;
 179         int ret;
 180
 181         for (size_t i = 0; i < table->capacity; i++) {
 182                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 183                                           hash_list)
 184                 {
 185                         ret = visitor(lte, arg);
 186                         if (ret != 0)
 187                                 return ret;
 188                 }
 189         }
 190         return 0;
 191 }
 192
 193
 194 /*
 195  * Reads the lookup table from a WIM file.
 196  */
 197 int read_lookup_table(WIMStruct *w)
 198 {
 199         u64    num_entries;
 200         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 201         int    ret;
 202         struct lookup_table *table;
 203         struct lookup_table_entry *cur_entry = NULL, *duplicate_entry;
 204
 205         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 206               w->hdr.lookup_table_res_entry.offset,
 207               w->hdr.lookup_table_res_entry.original_size);
 208
 209         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 210                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 211                                  "lookup table",
 212                                  w->hdr.lookup_table_res_entry.offset);
 213                 return WIMLIB_ERR_READ;
 214         }
 215
 216         num_entries = w->hdr.lookup_table_res_entry.original_size /
 217                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 218         table = new_lookup_table(num_entries * 2 + 1);
 219         if (!table)
 220                 return WIMLIB_ERR_NOMEM;
 221
 222         while (num_entries--) {
 223                 const u8 *p;
 224
 225                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 226                         if (feof(w->fp)) {
 227                                 ERROR("Unexpected EOF in WIM lookup table!");
 228                         } else {
 229                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 230                                                  "table");
 231                         }
 232                         ret = WIMLIB_ERR_READ;
 233                         goto out;
 234                 }
 235                 cur_entry = new_lookup_table_entry();
 236                 if (!cur_entry) {
 237                         ret = WIMLIB_ERR_NOMEM;
 238                         goto out;
 239                 }
 240                 cur_entry->wim = w;
 241                 cur_entry->resource_location = RESOURCE_IN_WIM;
 242
 243                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 244                 p = get_u16(p, &cur_entry->part_number);
 245                 p = get_u32(p, &cur_entry->refcnt);
 246                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 247
 248                 if (cur_entry->part_number != w->hdr.part_number) {
 249                         ERROR("A lookup table entry in part %hu of the WIM "
 250                               "points to part %hu",
 251                               w->hdr.part_number, cur_entry->part_number);
 252                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 253                         goto out_free_cur_entry;
 254
 255                 }
 256
 257                 if (is_zero_hash(cur_entry->hash)) {
 258                         ERROR("The WIM lookup table contains an entry with a "
 259                               "SHA1 message digest of all 0's");
 260                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 261                         goto out_free_cur_entry;
 262                 }
 263
 264                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 265                 if (duplicate_entry) {
 266                         ERROR("The WIM lookup table contains two entries with the "
 267                               "same SHA1 message digest!");
 268                         ERROR("The first entry is:");
 269                         print_lookup_table_entry(duplicate_entry);
 270                         ERROR("The second entry is:");
 271                         print_lookup_table_entry(cur_entry);
 272                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 273                         goto out_free_cur_entry;
 274                 }
 275
 276                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 277                     && (cur_entry->resource_entry.size !=
 278                       cur_entry->resource_entry.original_size))
 279                 {
 280                         ERROR("Found uncompressed resource with original size "
 281                               "not the same as compressed size");
 282                         ERROR("The lookup table entry for the resource is as follows:");
 283                         print_lookup_table_entry(cur_entry);
 284                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 285                         goto out_free_cur_entry;
 286                 }
 287                 lookup_table_insert(table, cur_entry);
 288
 289         }
 290         DEBUG("Done reading lookup table.");
 291         w->lookup_table = table;
 292         return 0;
 293 out_free_cur_entry:
 294         FREE(cur_entry);
 295 out:
 296         free_lookup_table(table);
 297         return ret;
 298 }
 299
 300
 301 /*
 302  * Writes a lookup table entry to the output file.
 303  */
 304 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 305 {
 306         FILE *out;
 307         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 308         u8 *p;
 309
 310         out = __out;
 311
 312         /* Don't write entries that have not had file resources or metadata
 313          * resources written for them. */
 314         if (lte->out_refcnt == 0)
 315                 return 0;
 316
 317         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 318                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 319                       ftello(out), lte->output_resource_entry.original_size);
 320
 321         p = put_resource_entry(buf, &lte->output_resource_entry);
 322         p = put_u16(p, lte->part_number);
 323         p = put_u32(p, lte->out_refcnt);
 324         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 325         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 326                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 327                 return WIMLIB_ERR_WRITE;
 328         }
 329         return 0;
 330 }
 331
 332
 333
 334 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
 335 {
 336         entry->out_refcnt = 0;
 337         return 0;
 338 }
 339
 340 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 341 {
 342         if (!lte) {
 343                 putchar('\n');
 344                 return;
 345         }
 346         printf("Offset            = %"PRIu64" bytes\n",
 347                lte->resource_entry.offset);
 348         printf("Size              = %"PRIu64" bytes\n",
 349                (u64)lte->resource_entry.size);
 350         printf("Original size     = %"PRIu64" bytes\n",
 351                lte->resource_entry.original_size);
 352         printf("Part Number       = %hu\n", lte->part_number);
 353         printf("Reference Count   = %u\n", lte->refcnt);
 354         printf("Hash              = 0x");
 355         print_hash(lte->hash);
 356         putchar('\n');
 357         printf("Flags             = ");
 358         u8 flags = lte->resource_entry.flags;
 359         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 360                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 361         if (flags & WIM_RESHDR_FLAG_FREE)
 362                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 363         if (flags & WIM_RESHDR_FLAG_METADATA)
 364                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 365         if (flags & WIM_RESHDR_FLAG_SPANNED)
 366                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 367         putchar('\n');
 368         switch (lte->resource_location) {
 369         case RESOURCE_IN_WIM:
 370                 if (lte->wim->filename) {
 371                         printf("WIM file          = `%s'\n",
 372                                lte->wim->filename);
 373                 }
 374                 break;
 375         case RESOURCE_IN_FILE_ON_DISK:
 376                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 377                 break;
 378         case RESOURCE_IN_STAGING_FILE:
 379                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 380                 break;
 381         default:
 382                 break;
 383         }
 384         putchar('\n');
 385 }
 386
 387 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 388                                        void *ignore)
 389 {
 390         print_lookup_table_entry(lte);
 391         return 0;
 392 }
 393
 394 /*
 395  * Prints the lookup table of a WIM file.
 396  */
 397 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 398 {
 399         for_lookup_table_entry(w->lookup_table,
 400                                do_print_lookup_table_entry,
 401                                NULL);
 402 }
 403
 404 /*
 405  * Looks up an entry in the lookup table.
 406  */
 407 struct lookup_table_entry *
 408 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 409 {
 410         size_t i;
 411         struct lookup_table_entry *lte;
 412         struct hlist_node *pos;
 413
 414         i = *(size_t*)hash % table->capacity;
 415         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 416                 if (hashes_equal(hash, lte->hash))
 417                         return lte;
 418         return NULL;
 419 }
 420
 421 /*
 422  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 423  * given a path name.
 424  *
 425  * This is only for pre-resolved dentries.
 426  */
 427 int lookup_resource(WIMStruct *w, const char *path,
 428                     int lookup_flags,
 429                     struct dentry **dentry_ret,
 430                     struct lookup_table_entry **lte_ret,
 431                     unsigned *stream_idx_ret)
 432 {
 433         struct dentry *dentry;
 434         struct lookup_table_entry *lte;
 435         unsigned stream_idx;
 436         const char *stream_name = NULL;
 437         char *p = NULL;
 438
 439         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 440                 stream_name = path_stream_name(path);
 441                 if (stream_name) {
 442                         p = (char*)stream_name - 1;
 443                         *p = '\0';
 444                 }
 445         }
 446
 447         dentry = get_dentry(w, path);
 448         if (p)
 449                 *p = ':';
 450         if (!dentry)
 451                 return -ENOENT;
 452
 453         wimlib_assert(dentry->resolved);
 454
 455         lte = dentry->lte;
 456         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 457               && dentry_is_directory(dentry))
 458                 return -EISDIR;
 459         stream_idx = 0;
 460         if (stream_name) {
 461                 size_t stream_name_len = strlen(stream_name);
 462                 for (u16 i = 0; i < dentry->num_ads; i++) {
 463                         if (ads_entry_has_name(&dentry->ads_entries[i],
 464                                                stream_name,
 465                                                stream_name_len))
 466                         {
 467                                 stream_idx = i + 1;
 468                                 lte = dentry->ads_entries[i].lte;
 469                                 goto out;
 470                         }
 471                 }
 472                 return -ENOENT;
 473         }
 474 out:
 475         if (dentry_ret)
 476                 *dentry_ret = dentry;
 477         if (lte_ret)
 478                 *lte_ret = lte;
 479         if (stream_idx_ret)
 480                 *stream_idx_ret = stream_idx;
 481         return 0;
 482 }
 483
 484 /* Resolve a dentry's lookup table entries
 485  *
 486  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 487  * lookup table) with pointers directly to the lookup table entries.  A circular
 488  * linked list of streams sharing the same lookup table entry is created.
 489  *
 490  * This function always succeeds; unresolved lookup table entries are given a
 491  * NULL pointer.
 492  */
 493 int dentry_resolve_ltes(struct dentry *dentry, void *__table)
 494 {
 495         struct lookup_table *table = __table;
 496         struct lookup_table_entry *lte;
 497
 498         if (dentry->resolved)
 499                 return 0;
 500
 501         /* Resolve the default file stream */
 502         lte = __lookup_resource(table, dentry->hash);
 503         if (lte)
 504                 list_add(&dentry->lte_group_list.list, &lte->lte_group_list);
 505         else
 506                 INIT_LIST_HEAD(&dentry->lte_group_list.list);
 507         dentry->lte = lte;
 508         dentry->lte_group_list.type = STREAM_TYPE_NORMAL;
 509         dentry->resolved = true;
 510
 511         /* Resolve the alternate data streams */
 512         if (dentry->ads_entries_status != ADS_ENTRIES_USER) {
 513                 for (u16 i = 0; i < dentry->num_ads; i++) {
 514                         struct ads_entry *cur_entry = &dentry->ads_entries[i];
 515
 516                         lte = __lookup_resource(table, cur_entry->hash);
 517                         if (lte)
 518                                 list_add(&cur_entry->lte_group_list.list,
 519                                          &lte->lte_group_list);
 520                         else
 521                                 INIT_LIST_HEAD(&cur_entry->lte_group_list.list);
 522                         cur_entry->lte = lte;
 523                         cur_entry->lte_group_list.type = STREAM_TYPE_ADS;
 524                 }
 525         }
 526         return 0;
 527 }
 528
 529 /* Return the lookup table entry for the unnamed data stream of a dentry, or
 530  * NULL if there is none.
 531  *
 532  * You'd think this would be easier than it actually is, since the unnamed data
 533  * stream should be the one referenced from the dentry itself.  Alas, if there
 534  * are named data streams, Microsoft's "imagex.exe" program will put the unnamed
 535  * data stream in one of the alternate data streams instead of inside the
 536  * dentry.  So we need to check the alternate data streams too.
 537  *
 538  * Also, note that a dentry may appear to have than one unnamed stream, but if
 539  * the SHA1 message digest is all 0's then the corresponding stream does not
 540  * really "count" (this is the case for the dentry's own file stream when the
 541  * file stream that should be there is actually in one of the alternate stream
 542  * entries.).  This is despite the fact that we may need to extract such a
 543  * missing entry as an empty file or empty named data stream.
 544  */
 545 struct lookup_table_entry *
 546 dentry_unnamed_lte(const struct dentry *dentry,
 547                    const struct lookup_table *table)
 548 {
 549         if (dentry->resolved)
 550                 return dentry_unnamed_lte_resolved(dentry);
 551         else
 552                 return dentry_unnamed_lte_unresolved(dentry, table);
 553 }
 554