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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->extracted_file);
 103                 FREE(lte);
 104         }
 105 }
 106
 107 static int do_free_lookup_table_entry(struct lookup_table_entry *entry,
 108                                       void *ignore)
 109 {
 110         free_lookup_table_entry(entry);
 111         return 0;
 112 }
 113
 114
 115 void free_lookup_table(struct lookup_table *table)
 116 {
 117         DEBUG2("Freeing lookup table");
 118         if (table) {
 119                 if (table->array) {
 120                         for_lookup_table_entry(table,
 121                                                do_free_lookup_table_entry,
 122                                                NULL);
 123                         FREE(table->array);
 124                 }
 125                 FREE(table);
 126         }
 127 }
 128
 129 /*
 130  * Inserts an entry into the lookup table.
 131  *
 132  * @table:      A pointer to the lookup table.
 133  * @entry:      A pointer to the entry to insert.
 134  */
 135 void lookup_table_insert(struct lookup_table *table,
 136                          struct lookup_table_entry *lte)
 137 {
 138         size_t i = lte->hash_short % table->capacity;
 139         hlist_add_head(&lte->hash_list, &table->array[i]);
 140
 141         /* XXX Make the table grow when too many entries have been inserted. */
 142         table->num_entries++;
 143 }
 144
 145
 146
 147 /* Decrements the reference count for the lookup table entry @lte.  If its
 148  * reference count reaches 0, it is unlinked from the lookup table.  If,
 149  * furthermore, the entry has no opened file descriptors associated with it, the
 150  * entry is freed.  */
 151 struct lookup_table_entry *
 152 lte_decrement_refcnt(struct lookup_table_entry *lte, struct lookup_table *table)
 153 {
 154         if (lte) {
 155                 wimlib_assert(lte->refcnt);
 156                 if (--lte->refcnt == 0) {
 157                         lookup_table_unlink(table, lte);
 158                 #ifdef WITH_FUSE
 159                         if (lte->num_opened_fds == 0)
 160                 #endif
 161                         {
 162                                 free_lookup_table_entry(lte);
 163                                 lte = NULL;
 164                         }
 165                 }
 166         }
 167         return lte;
 168 }
 169
 170 /*
 171  * Calls a function on all the entries in the lookup table.  Stop early and
 172  * return nonzero if any call to the function returns nonzero.
 173  */
 174 int for_lookup_table_entry(struct lookup_table *table,
 175                            int (*visitor)(struct lookup_table_entry *, void *),
 176                            void *arg)
 177 {
 178         struct lookup_table_entry *lte;
 179         struct hlist_node *pos, *tmp;
 180         int ret;
 181
 182         for (size_t i = 0; i < table->capacity; i++) {
 183                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 184                                           hash_list)
 185                 {
 186                         ret = visitor(lte, arg);
 187                         if (ret != 0)
 188                                 return ret;
 189                 }
 190         }
 191         return 0;
 192 }
 193
 194
 195 /*
 196  * Reads the lookup table from a WIM file.
 197  */
 198 int read_lookup_table(WIMStruct *w)
 199 {
 200         u64    num_entries;
 201         u8     buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 202         int    ret;
 203         struct lookup_table *table;
 204         struct lookup_table_entry *cur_entry = NULL, *duplicate_entry;
 205
 206         DEBUG("Reading lookup table: offset %"PRIu64", size %"PRIu64"",
 207               w->hdr.lookup_table_res_entry.offset,
 208               w->hdr.lookup_table_res_entry.original_size);
 209
 210         if (fseeko(w->fp, w->hdr.lookup_table_res_entry.offset, SEEK_SET) != 0) {
 211                 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
 212                                  "lookup table",
 213                                  w->hdr.lookup_table_res_entry.offset);
 214                 return WIMLIB_ERR_READ;
 215         }
 216
 217         num_entries = w->hdr.lookup_table_res_entry.original_size /
 218                       WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE;
 219         table = new_lookup_table(num_entries * 2 + 1);
 220         if (!table)
 221                 return WIMLIB_ERR_NOMEM;
 222
 223         while (num_entries--) {
 224                 const u8 *p;
 225
 226                 if (fread(buf, 1, sizeof(buf), w->fp) != sizeof(buf)) {
 227                         if (feof(w->fp)) {
 228                                 ERROR("Unexpected EOF in WIM lookup table!");
 229                         } else {
 230                                 ERROR_WITH_ERRNO("Error reading WIM lookup "
 231                                                  "table");
 232                         }
 233                         ret = WIMLIB_ERR_READ;
 234                         goto out;
 235                 }
 236                 cur_entry = new_lookup_table_entry();
 237                 if (!cur_entry) {
 238                         ret = WIMLIB_ERR_NOMEM;
 239                         goto out;
 240                 }
 241                 cur_entry->wim = w;
 242                 cur_entry->resource_location = RESOURCE_IN_WIM;
 243
 244                 p = get_resource_entry(buf, &cur_entry->resource_entry);
 245                 p = get_u16(p, &cur_entry->part_number);
 246                 p = get_u32(p, &cur_entry->refcnt);
 247                 p = get_bytes(p, SHA1_HASH_SIZE, cur_entry->hash);
 248
 249                 if (cur_entry->part_number != w->hdr.part_number) {
 250                         ERROR("A lookup table entry in part %hu of the WIM "
 251                               "points to part %hu",
 252                               w->hdr.part_number, cur_entry->part_number);
 253                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 254                         goto out_free_cur_entry;
 255
 256                 }
 257
 258                 if (is_zero_hash(cur_entry->hash)) {
 259                         ERROR("The WIM lookup table contains an entry with a "
 260                               "SHA1 message digest of all 0's");
 261                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 262                         goto out_free_cur_entry;
 263                 }
 264
 265                 duplicate_entry = __lookup_resource(table, cur_entry->hash);
 266                 if (duplicate_entry) {
 267                         ERROR("The WIM lookup table contains two entries with the "
 268                               "same SHA1 message digest!");
 269                         ERROR("The first entry is:");
 270                         print_lookup_table_entry(duplicate_entry);
 271                         ERROR("The second entry is:");
 272                         print_lookup_table_entry(cur_entry);
 273                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 274                         goto out_free_cur_entry;
 275                 }
 276
 277                 if (!(cur_entry->resource_entry.flags & WIM_RESHDR_FLAG_COMPRESSED)
 278                     && (cur_entry->resource_entry.size !=
 279                       cur_entry->resource_entry.original_size))
 280                 {
 281                         ERROR("Found uncompressed resource with original size "
 282                               "not the same as compressed size");
 283                         ERROR("The lookup table entry for the resource is as follows:");
 284                         print_lookup_table_entry(cur_entry);
 285                         ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 286                         goto out_free_cur_entry;
 287                 }
 288                 lookup_table_insert(table, cur_entry);
 289
 290         }
 291         DEBUG("Done reading lookup table.");
 292         w->lookup_table = table;
 293         return 0;
 294 out_free_cur_entry:
 295         FREE(cur_entry);
 296 out:
 297         free_lookup_table(table);
 298         return ret;
 299 }
 300
 301
 302 /*
 303  * Writes a lookup table entry to the output file.
 304  */
 305 int write_lookup_table_entry(struct lookup_table_entry *lte, void *__out)
 306 {
 307         FILE *out;
 308         u8 buf[WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE];
 309         u8 *p;
 310
 311         out = __out;
 312
 313         /* Don't write entries that have not had file resources or metadata
 314          * resources written for them. */
 315         if (lte->out_refcnt == 0)
 316                 return 0;
 317
 318         if (lte->output_resource_entry.flags & WIM_RESHDR_FLAG_METADATA)
 319                 DEBUG("Writing metadata entry at %lu (orig size = %zu)",
 320                       ftello(out), lte->output_resource_entry.original_size);
 321
 322         p = put_resource_entry(buf, &lte->output_resource_entry);
 323         p = put_u16(p, lte->part_number);
 324         p = put_u32(p, lte->out_refcnt);
 325         p = put_bytes(p, SHA1_HASH_SIZE, lte->hash);
 326         if (fwrite(buf, 1, sizeof(buf), out) != sizeof(buf)) {
 327                 ERROR_WITH_ERRNO("Failed to write lookup table entry");
 328                 return WIMLIB_ERR_WRITE;
 329         }
 330         return 0;
 331 }
 332
 333
 334
 335 int zero_out_refcnts(struct lookup_table_entry *entry, void *ignore)
 336 {
 337         entry->out_refcnt = 0;
 338         return 0;
 339 }
 340
 341 void print_lookup_table_entry(const struct lookup_table_entry *lte)
 342 {
 343         if (!lte) {
 344                 putchar('\n');
 345                 return;
 346         }
 347         printf("Offset            = %"PRIu64" bytes\n",
 348                lte->resource_entry.offset);
 349         printf("Size              = %"PRIu64" bytes\n",
 350                (u64)lte->resource_entry.size);
 351         printf("Original size     = %"PRIu64" bytes\n",
 352                lte->resource_entry.original_size);
 353         printf("Part Number       = %hu\n", lte->part_number);
 354         printf("Reference Count   = %u\n", lte->refcnt);
 355         printf("Hash              = 0x");
 356         print_hash(lte->hash);
 357         putchar('\n');
 358         printf("Flags             = ");
 359         u8 flags = lte->resource_entry.flags;
 360         if (flags & WIM_RESHDR_FLAG_COMPRESSED)
 361                 fputs("WIM_RESHDR_FLAG_COMPRESSED, ", stdout);
 362         if (flags & WIM_RESHDR_FLAG_FREE)
 363                 fputs("WIM_RESHDR_FLAG_FREE, ", stdout);
 364         if (flags & WIM_RESHDR_FLAG_METADATA)
 365                 fputs("WIM_RESHDR_FLAG_METADATA, ", stdout);
 366         if (flags & WIM_RESHDR_FLAG_SPANNED)
 367                 fputs("WIM_RESHDR_FLAG_SPANNED, ", stdout);
 368         putchar('\n');
 369         switch (lte->resource_location) {
 370         case RESOURCE_IN_WIM:
 371                 if (lte->wim->filename) {
 372                         printf("WIM file          = `%s'\n",
 373                                lte->wim->filename);
 374                 }
 375                 break;
 376         case RESOURCE_IN_FILE_ON_DISK:
 377                 printf("File on Disk      = `%s'\n", lte->file_on_disk);
 378                 break;
 379         case RESOURCE_IN_STAGING_FILE:
 380                 printf("Staging File      = `%s'\n", lte->staging_file_name);
 381                 break;
 382         default:
 383                 break;
 384         }
 385         putchar('\n');
 386 }
 387
 388 static int do_print_lookup_table_entry(struct lookup_table_entry *lte,
 389                                        void *ignore)
 390 {
 391         print_lookup_table_entry(lte);
 392         return 0;
 393 }
 394
 395 /*
 396  * Prints the lookup table of a WIM file.
 397  */
 398 WIMLIBAPI void wimlib_print_lookup_table(WIMStruct *w)
 399 {
 400         for_lookup_table_entry(w->lookup_table,
 401                                do_print_lookup_table_entry,
 402                                NULL);
 403 }
 404
 405 /*
 406  * Looks up an entry in the lookup table.
 407  */
 408 struct lookup_table_entry *
 409 __lookup_resource(const struct lookup_table *table, const u8 hash[])
 410 {
 411         size_t i;
 412         struct lookup_table_entry *lte;
 413         struct hlist_node *pos;
 414
 415         i = *(size_t*)hash % table->capacity;
 416         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 417                 if (hashes_equal(hash, lte->hash))
 418                         return lte;
 419         return NULL;
 420 }
 421
 422 /*
 423  * Finds the dentry, lookup table entry, and stream index for a WIM file stream,
 424  * given a path name.
 425  *
 426  * This is only for pre-resolved inodes.
 427  */
 428 int lookup_resource(WIMStruct *w, const char *path,
 429                     int lookup_flags,
 430                     struct dentry **dentry_ret,
 431                     struct lookup_table_entry **lte_ret,
 432                     unsigned *stream_idx_ret)
 433 {
 434         struct dentry *dentry;
 435         struct lookup_table_entry *lte;
 436         unsigned stream_idx;
 437         const char *stream_name = NULL;
 438         struct inode *inode;
 439         char *p = NULL;
 440
 441         if (lookup_flags & LOOKUP_FLAG_ADS_OK) {
 442                 stream_name = path_stream_name(path);
 443                 if (stream_name) {
 444                         p = (char*)stream_name - 1;
 445                         *p = '\0';
 446                 }
 447         }
 448
 449         dentry = get_dentry(w, path);
 450         if (p)
 451                 *p = ':';
 452         if (!dentry)
 453                 return -ENOENT;
 454
 455         inode = dentry->inode;
 456
 457         wimlib_assert(inode->resolved);
 458
 459         if (!(lookup_flags & LOOKUP_FLAG_DIRECTORY_OK)
 460               && inode_is_directory(inode))
 461                 return -EISDIR;
 462
 463         lte = inode->lte;
 464         stream_idx = 0;
 465         if (stream_name) {
 466                 size_t stream_name_len = strlen(stream_name);
 467                 for (u16 i = 0; i < inode->num_ads; i++) {
 468                         if (ads_entry_has_name(inode->ads_entries[i],
 469                                                stream_name,
 470                                                stream_name_len))
 471                         {
 472                                 stream_idx = i + 1;
 473                                 lte = inode->ads_entries[i]->lte;
 474                                 goto out;
 475                         }
 476                 }
 477                 return -ENOENT;
 478         }
 479 out:
 480         if (dentry_ret)
 481                 *dentry_ret = dentry;
 482         if (lte_ret)
 483                 *lte_ret = lte;
 484         if (stream_idx_ret)
 485                 *stream_idx_ret = stream_idx;
 486         return 0;
 487 }
 488
 489 static int inode_resolve_ltes(struct inode *inode, struct lookup_table *table)
 490 {
 491         struct lookup_table_entry *lte;
 492
 493         /* Resolve the default file stream */
 494         lte = __lookup_resource(table, inode->hash);
 495         if (lte)
 496                 list_add(&inode->lte_group_list.list, &lte->lte_group_list);
 497         else
 498                 INIT_LIST_HEAD(&inode->lte_group_list.list);
 499         inode->lte = lte;
 500         inode->lte_group_list.type = STREAM_TYPE_NORMAL;
 501         inode->resolved = true;
 502
 503         /* Resolve the alternate data streams */
 504         for (u16 i = 0; i < inode->num_ads; i++) {
 505                 struct ads_entry *cur_entry = inode->ads_entries[i];
 506
 507                 lte = __lookup_resource(table, cur_entry->hash);
 508                 if (lte)
 509                         list_add(&cur_entry->lte_group_list.list,
 510                                  &lte->lte_group_list);
 511                 else
 512                         INIT_LIST_HEAD(&cur_entry->lte_group_list.list);
 513                 cur_entry->lte = lte;
 514                 cur_entry->lte_group_list.type = STREAM_TYPE_ADS;
 515         }
 516         return 0;
 517 }
 518
 519 /* Resolve a dentry's lookup table entries
 520  *
 521  * This replaces the SHA1 hash fields (which are used to lookup an entry in the
 522  * lookup table) with pointers directly to the lookup table entries.  A circular
 523  * linked list of streams sharing the same lookup table entry is created.
 524  *
 525  * This function always succeeds; unresolved lookup table entries are given a
 526  * NULL pointer.
 527  */
 528 int dentry_resolve_ltes(struct dentry *dentry, void *table)
 529 {
 530         if (dentry->inode->resolved)
 531                 return 0;
 532         else
 533                 return inode_resolve_ltes(dentry->inode, table);
 534 }
 535
 536
 537
 538
 539 /* Return the lookup table entry for the unnamed data stream of a inode, or
 540  * NULL if there is none.
 541  *
 542  * You'd think this would be easier than it actually is, since the unnamed data
 543  * stream should be the one referenced from the inode itself.  Alas, if there
 544  * are named data streams, Microsoft's "imagex.exe" program will put the unnamed
 545  * data stream in one of the alternate data streams instead of inside the
 546  * inode.  So we need to check the alternate data streams too.
 547  *
 548  * Also, note that a inode may appear to have than one unnamed stream, but if
 549  * the SHA1 message digest is all 0's then the corresponding stream does not
 550  * really "count" (this is the case for the inode's own file stream when the
 551  * file stream that should be there is actually in one of the alternate stream
 552  * entries.).  This is despite the fact that we may need to extract such a
 553  * missing entry as an empty file or empty named data stream.
 554  */
 555 struct lookup_table_entry *
 556 inode_unnamed_lte(const struct inode *inode,
 557                    const struct lookup_table *table)
 558 {
 559         if (inode->resolved)
 560                 return inode_unnamed_lte_resolved(inode);
 561         else
 562                 return inode_unnamed_lte_unresolved(inode, table);
 563 }
 564