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   1 /*
   2  * lookup_table.c
   3  *
   4  * Lookup table, implemented as a hash table, that maps SHA1 message digests to
   5  * data streams; plus code to read and write the corresponding on-disk data.
   6  */
   7
   8 /*
   9  * Copyright (C) 2012, 2013 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 #ifdef HAVE_CONFIG_H
  28 #  include "config.h"
  29 #endif
  30
  31 #include "wimlib/assert.h"
  32 #include "wimlib/endianness.h"
  33 #include "wimlib/error.h"
  34 #include "wimlib/lookup_table.h"
  35 #include "wimlib/metadata.h"
  36 #include "wimlib/ntfs_3g.h"
  37 #include "wimlib/resource.h"
  38 #include "wimlib/util.h"
  39 #include "wimlib/write.h"
  40
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h> /* for unlink()  */
  44
  45 /* WIM lookup table:
  46  *
  47  * This is a logical mapping from SHA1 message digests to the data streams
  48  * contained in a WIM.
  49  *
  50  * Here it is implemented as a hash table.
  51  *
  52  * Note: Everything will break horribly if there is a SHA1 collision.
  53  */
  54 struct wim_lookup_table {
  55         struct hlist_head *array;
  56         size_t num_entries;
  57         size_t capacity;
  58 };
  59
  60 struct wim_lookup_table *
  61 new_lookup_table(size_t capacity)
  62 {
  63         struct wim_lookup_table *table;
  64         struct hlist_head *array;
  65
  66         table = MALLOC(sizeof(struct wim_lookup_table));
  67         if (table == NULL)
  68                 goto oom;
  69
  70         array = CALLOC(capacity, sizeof(array[0]));
  71         if (array == NULL) {
  72                 FREE(table);
  73                 goto oom;
  74         }
  75
  76         table->num_entries = 0;
  77         table->capacity = capacity;
  78         table->array = array;
  79         return table;
  80
  81 oom:
  82         ERROR("Failed to allocate memory for lookup table "
  83               "with capacity %zu", capacity);
  84         return NULL;
  85 }
  86
  87 static int
  88 do_free_lookup_table_entry(struct wim_lookup_table_entry *entry, void *ignore)
  89 {
  90         free_lookup_table_entry(entry);
  91         return 0;
  92 }
  93
  94 void
  95 free_lookup_table(struct wim_lookup_table *table)
  96 {
  97         DEBUG("Freeing lookup table.");
  98         if (table == NULL)
  99                 return;
 100
 101         if (table->array) {
 102                 for_lookup_table_entry(table,
 103                                        do_free_lookup_table_entry,
 104                                        NULL);
 105                 FREE(table->array);
 106         }
 107         FREE(table);
 108 }
 109
 110 struct wim_lookup_table_entry *
 111 new_lookup_table_entry(void)
 112 {
 113         struct wim_lookup_table_entry *lte;
 114
 115         lte = CALLOC(1, sizeof(struct wim_lookup_table_entry));
 116         if (lte == NULL)
 117                 return NULL;
 118
 119         lte->refcnt = 1;
 120
 121         /* lte->resource_location = RESOURCE_NONEXISTENT  */
 122         BUILD_BUG_ON(RESOURCE_NONEXISTENT != 0);
 123
 124         return lte;
 125 }
 126
 127 struct wim_lookup_table_entry *
 128 clone_lookup_table_entry(const struct wim_lookup_table_entry *old)
 129 {
 130         struct wim_lookup_table_entry *new;
 131
 132         new = memdup(old, sizeof(struct wim_lookup_table_entry));
 133         if (new == NULL)
 134                 return NULL;
 135
 136         new->extracted_file = NULL;
 137         switch (new->resource_location) {
 138         case RESOURCE_IN_WIM:
 139                 list_add(&new->rspec_node, &new->rspec->stream_list);
 140                 break;
 141
 142         case RESOURCE_IN_FILE_ON_DISK:
 143 #ifdef __WIN32__
 144         case RESOURCE_WIN32_ENCRYPTED:
 145 #endif
 146 #ifdef WITH_FUSE
 147         case RESOURCE_IN_STAGING_FILE:
 148                 BUILD_BUG_ON((void*)&old->file_on_disk !=
 149                              (void*)&old->staging_file_name);
 150 #endif
 151                 new->file_on_disk = TSTRDUP(old->file_on_disk);
 152                 if (new->file_on_disk == NULL)
 153                         goto out_free;
 154                 break;
 155         case RESOURCE_IN_ATTACHED_BUFFER:
 156                 new->attached_buffer = memdup(old->attached_buffer, old->size);
 157                 if (new->attached_buffer == NULL)
 158                         goto out_free;
 159                 break;
 160 #ifdef WITH_NTFS_3G
 161         case RESOURCE_IN_NTFS_VOLUME:
 162                 if (old->ntfs_loc) {
 163                         struct ntfs_location *loc;
 164                         loc = memdup(old->ntfs_loc, sizeof(struct ntfs_location));
 165                         if (loc == NULL)
 166                                 goto out_free;
 167                         loc->path = NULL;
 168                         loc->stream_name = NULL;
 169                         new->ntfs_loc = loc;
 170                         loc->path = STRDUP(old->ntfs_loc->path);
 171                         if (loc->path == NULL)
 172                                 goto out_free;
 173                         if (loc->stream_name_nchars != 0) {
 174                                 loc->stream_name = memdup(old->ntfs_loc->stream_name,
 175                                                           loc->stream_name_nchars * 2);
 176                                 if (loc->stream_name == NULL)
 177                                         goto out_free;
 178                         }
 179                 }
 180                 break;
 181 #endif
 182         default:
 183                 break;
 184         }
 185         return new;
 186
 187 out_free:
 188         free_lookup_table_entry(new);
 189         return NULL;
 190 }
 191
 192 void
 193 lte_put_resource(struct wim_lookup_table_entry *lte)
 194 {
 195         switch (lte->resource_location) {
 196         case RESOURCE_IN_WIM:
 197                 list_del(&lte->rspec_node);
 198                 if (list_empty(&lte->rspec->stream_list))
 199                         FREE(lte->rspec);
 200                 break;
 201         case RESOURCE_IN_FILE_ON_DISK:
 202 #ifdef __WIN32__
 203         case RESOURCE_WIN32_ENCRYPTED:
 204 #endif
 205 #ifdef WITH_FUSE
 206         case RESOURCE_IN_STAGING_FILE:
 207                 BUILD_BUG_ON((void*)&lte->file_on_disk !=
 208                              (void*)&lte->staging_file_name);
 209 #endif
 210         case RESOURCE_IN_ATTACHED_BUFFER:
 211                 BUILD_BUG_ON((void*)&lte->file_on_disk !=
 212                              (void*)&lte->attached_buffer);
 213                 FREE(lte->file_on_disk);
 214                 break;
 215 #ifdef WITH_NTFS_3G
 216         case RESOURCE_IN_NTFS_VOLUME:
 217                 if (lte->ntfs_loc) {
 218                         FREE(lte->ntfs_loc->path);
 219                         FREE(lte->ntfs_loc->stream_name);
 220                         FREE(lte->ntfs_loc);
 221                 }
 222                 break;
 223 #endif
 224         default:
 225                 break;
 226         }
 227 }
 228
 229 void
 230 free_lookup_table_entry(struct wim_lookup_table_entry *lte)
 231 {
 232         if (lte) {
 233                 lte_put_resource(lte);
 234                 FREE(lte);
 235         }
 236 }
 237
 238 /* Decrements the reference count for the lookup table entry @lte.  If its
 239  * reference count reaches 0, it is unlinked from the lookup table.  If,
 240  * furthermore, the entry has no opened file descriptors associated with it, the
 241  * entry is freed.  */
 242 void
 243 lte_decrement_refcnt(struct wim_lookup_table_entry *lte,
 244                      struct wim_lookup_table *table)
 245 {
 246         wimlib_assert(lte->refcnt != 0);
 247
 248         if (--lte->refcnt == 0) {
 249                 if (lte->unhashed) {
 250                         list_del(&lte->unhashed_list);
 251                 #ifdef WITH_FUSE
 252                         /* If the stream has been extracted to a staging file
 253                          * for a FUSE mount, unlink the staging file.  (Note
 254                          * that there still may be open file descriptors to it.)
 255                          * */
 256                         if (lte->resource_location == RESOURCE_IN_STAGING_FILE)
 257                                 unlink(lte->staging_file_name);
 258                 #endif
 259                 } else {
 260                         lookup_table_unlink(table, lte);
 261                 }
 262
 263                 /* If FUSE mounts are enabled, we don't actually free the entry
 264                  * until the last file descriptor has been closed by
 265                  * lte_decrement_num_opened_fds().  */
 266 #ifdef WITH_FUSE
 267                 if (lte->num_opened_fds == 0)
 268 #endif
 269                         free_lookup_table_entry(lte);
 270         }
 271 }
 272
 273 #ifdef WITH_FUSE
 274 void
 275 lte_decrement_num_opened_fds(struct wim_lookup_table_entry *lte)
 276 {
 277         wimlib_assert(lte->num_opened_fds != 0);
 278
 279         if (--lte->num_opened_fds == 0 && lte->refcnt == 0)
 280                 free_lookup_table_entry(lte);
 281 }
 282 #endif
 283
 284 static void
 285 lookup_table_insert_raw(struct wim_lookup_table *table,
 286                         struct wim_lookup_table_entry *lte)
 287 {
 288         size_t i = lte->hash_short % table->capacity;
 289
 290         hlist_add_head(&lte->hash_list, &table->array[i]);
 291 }
 292
 293 static void
 294 enlarge_lookup_table(struct wim_lookup_table *table)
 295 {
 296         size_t old_capacity, new_capacity;
 297         struct hlist_head *old_array, *new_array;
 298         struct wim_lookup_table_entry *lte;
 299         struct hlist_node *cur, *tmp;
 300         size_t i;
 301
 302         old_capacity = table->capacity;
 303         new_capacity = old_capacity * 2;
 304         new_array = CALLOC(new_capacity, sizeof(struct hlist_head));
 305         if (new_array == NULL)
 306                 return;
 307         old_array = table->array;
 308         table->array = new_array;
 309         table->capacity = new_capacity;
 310
 311         for (i = 0; i < old_capacity; i++) {
 312                 hlist_for_each_entry_safe(lte, cur, tmp, &old_array[i], hash_list) {
 313                         hlist_del(&lte->hash_list);
 314                         lookup_table_insert_raw(table, lte);
 315                 }
 316         }
 317         FREE(old_array);
 318 }
 319
 320 /* Inserts an entry into the lookup table.  */
 321 void
 322 lookup_table_insert(struct wim_lookup_table *table,
 323                     struct wim_lookup_table_entry *lte)
 324 {
 325         lookup_table_insert_raw(table, lte);
 326         if (++table->num_entries > table->capacity)
 327                 enlarge_lookup_table(table);
 328 }
 329
 330 /* Unlinks a lookup table entry from the table; does not free it.  */
 331 void
 332 lookup_table_unlink(struct wim_lookup_table *table,
 333                     struct wim_lookup_table_entry *lte)
 334 {
 335         wimlib_assert(!lte->unhashed);
 336         wimlib_assert(table->num_entries != 0);
 337
 338         hlist_del(&lte->hash_list);
 339         table->num_entries--;
 340 }
 341
 342 /* Given a SHA1 message digest, return the corresponding entry in the WIM's
 343  * lookup table, or NULL if there is none.  */
 344 struct wim_lookup_table_entry *
 345 lookup_stream(const struct wim_lookup_table *table, const u8 hash[])
 346 {
 347         size_t i;
 348         struct wim_lookup_table_entry *lte;
 349         struct hlist_node *pos;
 350
 351         i = *(size_t*)hash % table->capacity;
 352         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 353                 if (hashes_equal(hash, lte->hash))
 354                         return lte;
 355         return NULL;
 356 }
 357
 358 /* Calls a function on all the entries in the WIM lookup table.  Stop early and
 359  * return nonzero if any call to the function returns nonzero. */
 360 int
 361 for_lookup_table_entry(struct wim_lookup_table *table,
 362                        int (*visitor)(struct wim_lookup_table_entry *, void *),
 363                        void *arg)
 364 {
 365         struct wim_lookup_table_entry *lte;
 366         struct hlist_node *pos, *tmp;
 367         int ret;
 368
 369         for (size_t i = 0; i < table->capacity; i++) {
 370                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 371                                           hash_list)
 372                 {
 373                         ret = visitor(lte, arg);
 374                         if (ret)
 375                                 return ret;
 376                 }
 377         }
 378         return 0;
 379 }
 380
 381 /* qsort() callback that sorts streams (represented by `struct
 382  * wim_lookup_table_entry's) into an order optimized for reading.
 383  *
 384  * Sorting is done primarily by resource location, then secondarily by a
 385  * per-resource location order.  For example, resources in WIM files are sorted
 386  * primarily by part number, then secondarily by offset, as to implement optimal
 387  * reading of either a standalone or split WIM.  */
 388 static int
 389 cmp_streams_by_sequential_order(const void *p1, const void *p2)
 390 {
 391         const struct wim_lookup_table_entry *lte1, *lte2;
 392         int v;
 393         WIMStruct *wim1, *wim2;
 394
 395         lte1 = *(const struct wim_lookup_table_entry**)p1;
 396         lte2 = *(const struct wim_lookup_table_entry**)p2;
 397
 398         v = (int)lte1->resource_location - (int)lte2->resource_location;
 399
 400         /* Different resource locations?  */
 401         if (v)
 402                 return v;
 403
 404         switch (lte1->resource_location) {
 405         case RESOURCE_IN_WIM:
 406                 wim1 = lte1->rspec->wim;
 407                 wim2 = lte2->rspec->wim;
 408
 409                 /* Different (possibly split) WIMs?  */
 410                 if (wim1 != wim2) {
 411                         v = memcmp(wim1->hdr.guid, wim2->hdr.guid, WIM_GID_LEN);
 412                         if (v)
 413                                 return v;
 414                 }
 415
 416                 /* Different part numbers in the same WIM?  */
 417                 v = (int)wim1->hdr.part_number - (int)wim2->hdr.part_number;
 418                 if (v)
 419                         return v;
 420
 421                 if (lte1->rspec->offset_in_wim != lte2->rspec->offset_in_wim)
 422                         return cmp_u64(lte1->rspec->offset_in_wim,
 423                                        lte2->rspec->offset_in_wim);
 424
 425                 return cmp_u64(lte1->offset_in_res, lte2->offset_in_res);
 426
 427         case RESOURCE_IN_FILE_ON_DISK:
 428 #ifdef WITH_FUSE
 429         case RESOURCE_IN_STAGING_FILE:
 430 #endif
 431 #ifdef __WIN32__
 432         case RESOURCE_WIN32_ENCRYPTED:
 433 #endif
 434                 /* Compare files by path: just a heuristic that will place files
 435                  * in the same directory next to each other.  */
 436                 return tstrcmp(lte1->file_on_disk, lte2->file_on_disk);
 437 #ifdef WITH_NTFS_3G
 438         case RESOURCE_IN_NTFS_VOLUME:
 439                 return tstrcmp(lte1->ntfs_loc->path, lte2->ntfs_loc->path);
 440 #endif
 441         default:
 442                 /* No additional sorting order defined for this resource
 443                  * location (e.g. RESOURCE_IN_ATTACHED_BUFFER); simply compare
 444                  * everything equal to each other.  */
 445                 return 0;
 446         }
 447 }
 448
 449 int
 450 sort_stream_list(struct list_head *stream_list,
 451                  size_t list_head_offset,
 452                  int (*compar)(const void *, const void*))
 453 {
 454         struct list_head *cur;
 455         struct wim_lookup_table_entry **array;
 456         size_t i;
 457         size_t array_size;
 458         size_t num_streams = 0;
 459
 460         list_for_each(cur, stream_list)
 461                 num_streams++;
 462
 463         if (num_streams <= 1)
 464                 return 0;
 465
 466         array_size = num_streams * sizeof(array[0]);
 467         array = MALLOC(array_size);
 468         if (array == NULL)
 469                 return WIMLIB_ERR_NOMEM;
 470
 471         cur = stream_list->next;
 472         for (i = 0; i < num_streams; i++) {
 473                 array[i] = (struct wim_lookup_table_entry*)((u8*)cur -
 474                                                             list_head_offset);
 475                 cur = cur->next;
 476         }
 477
 478         qsort(array, num_streams, sizeof(array[0]), compar);
 479
 480         INIT_LIST_HEAD(stream_list);
 481         for (i = 0; i < num_streams; i++) {
 482                 list_add_tail((struct list_head*)
 483                                ((u8*)array[i] + list_head_offset),
 484                               stream_list);
 485         }
 486         FREE(array);
 487         return 0;
 488 }
 489
 490 /* Sort the specified list of streams in an order optimized for reading.  */
 491 int
 492 sort_stream_list_by_sequential_order(struct list_head *stream_list,
 493                                      size_t list_head_offset)
 494 {
 495         return sort_stream_list(stream_list, list_head_offset,
 496                                 cmp_streams_by_sequential_order);
 497 }
 498
 499
 500 static int
 501 add_lte_to_array(struct wim_lookup_table_entry *lte,
 502                  void *_pp)
 503 {
 504         struct wim_lookup_table_entry ***pp = _pp;
 505         *(*pp)++ = lte;
 506         return 0;
 507 }
 508
 509 /* Iterate through the lookup table entries, but first sort them by stream
 510  * offset in the WIM.  Caution: this is intended to be used when the stream
 511  * offset field has actually been set. */
 512 int
 513 for_lookup_table_entry_pos_sorted(struct wim_lookup_table *table,
 514                                   int (*visitor)(struct wim_lookup_table_entry *,
 515                                                  void *),
 516                                   void *arg)
 517 {
 518         struct wim_lookup_table_entry **lte_array, **p;
 519         size_t num_streams = table->num_entries;
 520         int ret;
 521
 522         lte_array = MALLOC(num_streams * sizeof(lte_array[0]));
 523         if (!lte_array)
 524                 return WIMLIB_ERR_NOMEM;
 525         p = lte_array;
 526         for_lookup_table_entry(table, add_lte_to_array, &p);
 527
 528         wimlib_assert(p == lte_array + num_streams);
 529
 530         qsort(lte_array, num_streams, sizeof(lte_array[0]),
 531               cmp_streams_by_sequential_order);
 532         ret = 0;
 533         for (size_t i = 0; i < num_streams; i++) {
 534                 ret = visitor(lte_array[i], arg);
 535                 if (ret)
 536                         break;
 537         }
 538         FREE(lte_array);
 539         return ret;
 540 }
 541
 542 /* On-disk format of a WIM lookup table entry (stream entry). */
 543 struct wim_lookup_table_entry_disk {
 544         /* Size, offset, and flags of the stream.  */
 545         struct wim_reshdr_disk reshdr;
 546
 547         /* Which part of the split WIM this stream is in; indexed from 1. */
 548         le16 part_number;
 549
 550         /* Reference count of this stream over all WIM images. */
 551         le32 refcnt;
 552
 553         /* SHA1 message digest of the uncompressed data of this stream, or
 554          * optionally all zeroes if this stream is of zero length. */
 555         u8 hash[SHA1_HASH_SIZE];
 556 } _packed_attribute;
 557
 558 #define WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE 50
 559
 560 /* Validate the size and location of a WIM resource.  */
 561 static int
 562 validate_resource(const struct wim_resource_spec *rspec)
 563 {
 564         struct wim_lookup_table_entry *lte;
 565         u64 cur_offset;
 566
 567         /* Verify that calculating the offset of the end of the resource doesn't
 568          * overflow.  */
 569         if (rspec->offset_in_wim + rspec->size_in_wim < rspec->size_in_wim)
 570                 goto invalid;
 571
 572         /* Verify that each stream in the resource has a valid offset and size,
 573          * and that no streams overlap, and that the streams were added in order
 574          * of increasing offset.  */
 575         cur_offset = 0;
 576         list_for_each_entry(lte, &rspec->stream_list, rspec_node) {
 577                 if (lte->offset_in_res + lte->size < lte->size ||
 578                     lte->offset_in_res + lte->size > rspec->uncompressed_size ||
 579                     lte->offset_in_res < cur_offset)
 580                         goto invalid;
 581
 582                 cur_offset = lte->offset_in_res + lte->size;
 583         }
 584         return 0;
 585
 586 invalid:
 587
 588         ERROR("Invalid resource entry!");
 589         return WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 590 }
 591
 592 /*
 593  * Reads the lookup table from a WIM file.  Each entry specifies a stream that
 594  * the WIM file contains, along with its location and SHA1 message digest.
 595  *
 596  * Saves lookup table entries for non-metadata streams in a hash table, and
 597  * saves the metadata entry for each image in a special per-image location (the
 598  * image_metadata array).
 599  *
 600  * Return values:
 601  *      WIMLIB_ERR_SUCCESS (0)
 602  *      WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY
 603  *      WIMLIB_ERR_RESOURCE_NOT_FOUND
 604  *
 605  *      Or an error code caused by failure to read the lookup table into memory.
 606  */
 607 int
 608 read_wim_lookup_table(WIMStruct *wim)
 609 {
 610         int ret;
 611         size_t i;
 612         size_t num_entries;
 613         struct wim_lookup_table *table;
 614         struct wim_lookup_table_entry *cur_entry, *duplicate_entry;
 615         struct wim_resource_spec *cur_rspec;
 616         void *buf;
 617         bool back_to_back_pack;
 618         size_t num_duplicate_entries = 0;
 619
 620         DEBUG("Reading lookup table.");
 621
 622         /* Sanity check: lookup table entries are 50 bytes each.  */
 623         BUILD_BUG_ON(sizeof(struct wim_lookup_table_entry_disk) !=
 624                      WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE);
 625
 626         /* Calculate number of entries in the lookup table.  */
 627         num_entries = wim->hdr.lookup_table_reshdr.uncompressed_size /
 628                       sizeof(struct wim_lookup_table_entry_disk);
 629
 630         /* Read the lookup table into a buffer.  */
 631         ret = wim_reshdr_to_data(&wim->hdr.lookup_table_reshdr, wim, &buf);
 632         if (ret)
 633                 goto out;
 634
 635         /* Allocate a hash table to map SHA1 message digests into stream
 636          * specifications.  This is the in-memory "lookup table".  */
 637         table = new_lookup_table(num_entries * 2 + 1);
 638         if (table == NULL) {
 639                 ERROR("Not enough memory to read lookup table.");
 640                 ret = WIMLIB_ERR_NOMEM;
 641                 goto out_free_buf;
 642         }
 643
 644         /* Allocate and initalize stream entries from the raw lookup table
 645          * buffer.  */
 646         wim->current_image = 0;
 647         cur_rspec = NULL;
 648         for (i = 0; i < num_entries; i++) {
 649                 const struct wim_lookup_table_entry_disk *disk_entry =
 650                         &((const struct wim_lookup_table_entry_disk*)buf)[i];
 651                 u16 part_number;
 652                 struct wim_reshdr reshdr;
 653
 654                 get_wim_reshdr(&disk_entry->reshdr, &reshdr);
 655
 656                 DEBUG("reshdr: size_in_wim=%"PRIu64", "
 657                       "uncompressed_size=%"PRIu64", "
 658                       "offset_in_wim=%"PRIu64", "
 659                       "flags=0x%02x",
 660                       reshdr.size_in_wim, reshdr.uncompressed_size,
 661                       reshdr.offset_in_wim, reshdr.flags);
 662
 663                 if (wim->hdr.wim_version == WIM_VERSION_DEFAULT)
 664                         reshdr.flags &= ~WIM_RESHDR_FLAG_PACKED_STREAMS;
 665
 666                 cur_entry = new_lookup_table_entry();
 667                 if (cur_entry == NULL) {
 668                         ERROR("Not enough memory to read lookup table!");
 669                         ret = WIMLIB_ERR_NOMEM;
 670                         goto err;
 671                 }
 672
 673                 part_number = le16_to_cpu(disk_entry->part_number);
 674                 cur_entry->refcnt = le32_to_cpu(disk_entry->refcnt);
 675                 copy_hash(cur_entry->hash, disk_entry->hash);
 676
 677                 if (part_number != wim->hdr.part_number) {
 678                         WARNING("A lookup table entry in part %hu of the WIM "
 679                                 "points to part %hu (ignoring it)",
 680                                 wim->hdr.part_number, part_number);
 681                         free_lookup_table_entry(cur_entry);
 682                         continue;
 683                 }
 684
 685                 if (!(reshdr.flags & (WIM_RESHDR_FLAG_PACKED_STREAMS |
 686                                       WIM_RESHDR_FLAG_COMPRESSED))) {
 687                         if (reshdr.uncompressed_size != reshdr.size_in_wim) {
 688                                 /* So ... This is an uncompressed resource, but
 689                                  * its uncompressed size is NOT the same as its
 690                                  * "compressed" size (size_in_wim).  What to do
 691                                  * with it?
 692                                  *
 693                                  * Based on a simple test, WIMGAPI seems to
 694                                  * handle this as follows:
 695                                  *
 696                                  * if (size_in_wim > uncompressed_size) {
 697                                  *      Ignore uncompressed_size; use
 698                                  *      size_in_wim instead.
 699                                  * } else {
 700                                  *      Honor uncompressed_size, but treat the
 701                                  *      part of the file data above size_in_wim
 702                                  *      as all zeros.
 703                                  * }
 704                                  *
 705                                  * So we will do the same.
 706                                  */
 707                                 if (reshdr.size_in_wim > reshdr.uncompressed_size)
 708                                         reshdr.uncompressed_size = reshdr.size_in_wim;
 709                         }
 710                 }
 711
 712                 back_to_back_pack = false;
 713                 if (!(reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) ||
 714                     cur_rspec == NULL ||
 715                     (back_to_back_pack =
 716                      ((reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) &&
 717                       reshdr.uncompressed_size == WIM_PACK_MAGIC_NUMBER &&
 718                       cur_rspec != NULL &&
 719                       cur_rspec->size_in_wim != 0)))
 720                 {
 721                         /* Starting new run of streams that share the same WIM
 722                          * resource.  */
 723                         struct wim_lookup_table_entry *prev_entry = NULL;
 724
 725                         if (back_to_back_pack &&
 726                             !list_empty(&cur_rspec->stream_list))
 727                         {
 728                                 prev_entry = list_entry(cur_rspec->stream_list.prev,
 729                                                         struct wim_lookup_table_entry,
 730                                                         rspec_node);
 731                                 lte_unbind_wim_resource_spec(prev_entry);
 732                         }
 733                         if (cur_rspec != NULL) {
 734                                 ret = validate_resource(cur_rspec);
 735                                 if (ret)
 736                                         goto err;
 737                         }
 738
 739                         /* Allocate the resource specification and initialize it
 740                          * with values from the current stream entry.  */
 741                         cur_rspec = MALLOC(sizeof(*cur_rspec));
 742                         if (cur_rspec == NULL) {
 743                                 ERROR("Not enough memory to read lookup table!");
 744                                 ret = WIMLIB_ERR_NOMEM;
 745                                 goto err;
 746                         }
 747                         wim_res_hdr_to_spec(&reshdr, wim, cur_rspec);
 748
 749                         /* If this is a packed run, the current stream entry may
 750                          * specify a stream within the resource, and not the
 751                          * resource itself.  Zero possibly irrelevant data until
 752                          * it is read for certain.  (Note that the computation
 753                          * of 'back_to_back_pack' tests if 'size_in_wim' is
 754                          * nonzero to see if the resource info has been read;
 755                          * hence we need to set it to 0 here.)  */
 756                         if (reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
 757                                 cur_rspec->size_in_wim = 0;
 758                                 cur_rspec->uncompressed_size = 0;
 759                                 cur_rspec->offset_in_wim = 0;
 760                         }
 761
 762                         if (prev_entry)
 763                                 lte_bind_wim_resource_spec(prev_entry, cur_rspec);
 764                 }
 765
 766                 if ((reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) &&
 767                     reshdr.uncompressed_size == WIM_PACK_MAGIC_NUMBER)
 768                 {
 769                         /* Found the specification for the packed resource.
 770                          * Transfer the values to the `struct
 771                          * wim_resource_spec', and discard the current stream
 772                          * since this lookup table entry did not, in fact,
 773                          * correspond to a "stream".
 774                          */
 775
 776                         /* Uncompressed size of the resource pack is actually
 777                          * stored in the header of the resource itself.  Read
 778                          * it, and also grab the chunk size and compression type
 779                          * (which are not necessarily the defaults from the WIM
 780                          * header).  */
 781                         struct alt_chunk_table_header_disk hdr;
 782
 783                         ret = full_pread(&wim->in_fd, &hdr,
 784                                          sizeof(hdr), reshdr.offset_in_wim);
 785                         if (ret)
 786                                 goto err;
 787
 788                         cur_rspec->uncompressed_size = le64_to_cpu(hdr.res_usize);
 789                         cur_rspec->offset_in_wim = reshdr.offset_in_wim;
 790                         cur_rspec->size_in_wim = reshdr.size_in_wim;
 791                         cur_rspec->flags = reshdr.flags;
 792
 793                         /* Compression format numbers must be the same as in
 794                          * WIMGAPI to be compatible here.  */
 795                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_NONE != 0);
 796                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_XPRESS != 1);
 797                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZX != 2);
 798                         BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZMS != 3);
 799                         cur_rspec->compression_type = le32_to_cpu(hdr.compression_format);
 800
 801                         cur_rspec->chunk_size = le32_to_cpu(hdr.chunk_size);
 802
 803                         DEBUG("Full pack is %"PRIu64" compressed bytes "
 804                               "at file offset %"PRIu64" (flags 0x%02x)",
 805                               cur_rspec->size_in_wim,
 806                               cur_rspec->offset_in_wim,
 807                               cur_rspec->flags);
 808                         free_lookup_table_entry(cur_entry);
 809                         continue;
 810                 }
 811
 812                 if (is_zero_hash(cur_entry->hash)) {
 813                         free_lookup_table_entry(cur_entry);
 814                         continue;
 815                 }
 816
 817                 if (reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
 818                         /* Continuing the pack with another stream.  */
 819                         DEBUG("Continuing pack with stream: "
 820                               "%"PRIu64" uncompressed bytes @ "
 821                               "resource offset %"PRIu64")",
 822                               reshdr.size_in_wim, reshdr.offset_in_wim);
 823                 }
 824
 825                 lte_bind_wim_resource_spec(cur_entry, cur_rspec);
 826                 if (reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
 827                         /* In packed runs, the offset field is used for
 828                          * in-resource offset, not the in-WIM offset, and the
 829                          * size field is used for the uncompressed size, not the
 830                          * compressed size.  */
 831                         cur_entry->offset_in_res = reshdr.offset_in_wim;
 832                         cur_entry->size = reshdr.size_in_wim;
 833                         cur_entry->flags = reshdr.flags;
 834                 } else {
 835                         /* Normal case: The stream corresponds one-to-one with
 836                          * the resource entry.  */
 837                         cur_entry->offset_in_res = 0;
 838                         cur_entry->size = reshdr.uncompressed_size;
 839                         cur_entry->flags = reshdr.flags;
 840                         cur_rspec = NULL;
 841                 }
 842
 843                 if (cur_entry->flags & WIM_RESHDR_FLAG_METADATA) {
 844                         /* Lookup table entry for a metadata resource */
 845
 846                         /* Metadata entries with no references must be ignored;
 847                          * see for example the WinPE WIMs from the WAIK v2.1.
 848                          * */
 849                         if (cur_entry->refcnt == 0) {
 850                                 free_lookup_table_entry(cur_entry);
 851                                 continue;
 852                         }
 853
 854                         if (cur_entry->refcnt != 1) {
 855                                 ERROR("Found metadata resource with refcnt != 1");
 856                                 ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 857                                 goto err;
 858                         }
 859
 860                         if (wim->hdr.part_number != 1) {
 861                                 WARNING("Ignoring metadata resource found in a "
 862                                         "non-first part of the split WIM");
 863                                 free_lookup_table_entry(cur_entry);
 864                                 continue;
 865                         }
 866                         if (wim->current_image == wim->hdr.image_count) {
 867                                 WARNING("The WIM header says there are %u images "
 868                                         "in the WIM, but we found more metadata "
 869                                         "resources than this (ignoring the extra)",
 870                                         wim->hdr.image_count);
 871                                 free_lookup_table_entry(cur_entry);
 872                                 continue;
 873                         }
 874
 875                         /* Notice very carefully:  We are assigning the metadata
 876                          * resources in the exact order mirrored by their lookup
 877                          * table entries on disk, which is the behavior of
 878                          * Microsoft's software.  In particular, this overrides
 879                          * the actual locations of the metadata resources
 880                          * themselves in the WIM file as well as any information
 881                          * written in the XML data. */
 882                         DEBUG("Found metadata resource for image %u at "
 883                               "offset %"PRIu64".",
 884                               wim->current_image + 1,
 885                               cur_entry->rspec->offset_in_wim);
 886                         wim->image_metadata[
 887                                 wim->current_image++]->metadata_lte = cur_entry;
 888                         continue;
 889                 }
 890
 891                 /* Lookup table entry for a stream that is not a metadata
 892                  * resource.  */
 893                 duplicate_entry = lookup_stream(table, cur_entry->hash);
 894                 if (duplicate_entry) {
 895                         num_duplicate_entries++;
 896                         free_lookup_table_entry(cur_entry);
 897                         continue;
 898                 }
 899
 900                 /* Finally, insert the stream into the lookup table, keyed by
 901                  * its SHA1 message digest.  */
 902                 lookup_table_insert(table, cur_entry);
 903         }
 904         cur_entry = NULL;
 905
 906         /* Validate the last resource.  */
 907         if (cur_rspec != NULL) {
 908                 ret = validate_resource(cur_rspec);
 909                 if (ret)
 910                         goto err;
 911         }
 912
 913         if (wim->hdr.part_number == 1 && wim->current_image != wim->hdr.image_count) {
 914                 WARNING("The header of \"%"TS"\" says there are %u images in\n"
 915                         "          the WIM, but we only found %d metadata resources!  Acting as if\n"
 916                         "          the header specified only %d images instead.",
 917                         wim->filename, wim->hdr.image_count,
 918                         wim->current_image, wim->current_image);
 919                 for (int i = wim->current_image; i < wim->hdr.image_count; i++)
 920                         put_image_metadata(wim->image_metadata[i], NULL);
 921                 wim->hdr.image_count = wim->current_image;
 922         }
 923
 924         if (num_duplicate_entries > 0) {
 925                 WARNING("Ignoring %zu duplicate streams in the WIM lookup table",
 926                         num_duplicate_entries);
 927         }
 928
 929         DEBUG("Done reading lookup table.");
 930         wim->lookup_table = table;
 931         ret = 0;
 932         goto out_free_buf;
 933
 934 err:
 935         if (cur_rspec && list_empty(&cur_rspec->stream_list))
 936                 FREE(cur_rspec);
 937         free_lookup_table_entry(cur_entry);
 938         free_lookup_table(table);
 939 out_free_buf:
 940         FREE(buf);
 941 out:
 942         wim->current_image = 0;
 943         return ret;
 944 }
 945
 946 static void
 947 put_wim_lookup_table_entry(struct wim_lookup_table_entry_disk *disk_entry,
 948                            const struct wim_reshdr *out_reshdr,
 949                            u16 part_number, u32 refcnt, const u8 *hash)
 950 {
 951         put_wim_reshdr(out_reshdr, &disk_entry->reshdr);
 952         disk_entry->part_number = cpu_to_le16(part_number);
 953         disk_entry->refcnt = cpu_to_le32(refcnt);
 954         copy_hash(disk_entry->hash, hash);
 955 }
 956
 957 int
 958 write_wim_lookup_table_from_stream_list(struct list_head *stream_list,
 959                                         struct filedes *out_fd,
 960                                         u16 part_number,
 961                                         struct wim_reshdr *out_reshdr,
 962                                         int write_resource_flags)
 963 {
 964         size_t table_size;
 965         struct wim_lookup_table_entry *lte;
 966         struct wim_lookup_table_entry_disk *table_buf;
 967         struct wim_lookup_table_entry_disk *table_buf_ptr;
 968         int ret;
 969         u64 prev_res_offset_in_wim = ~0ULL;
 970
 971         table_size = 0;
 972         list_for_each_entry(lte, stream_list, lookup_table_list) {
 973                 table_size += sizeof(struct wim_lookup_table_entry_disk);
 974
 975                 if (lte->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS &&
 976                     lte->out_res_offset_in_wim != prev_res_offset_in_wim)
 977                 {
 978                         table_size += sizeof(struct wim_lookup_table_entry_disk);
 979                         prev_res_offset_in_wim = lte->out_res_offset_in_wim;
 980                 }
 981         }
 982
 983         DEBUG("Writing WIM lookup table (size=%zu, offset=%"PRIu64")",
 984               table_size, out_fd->offset);
 985
 986         table_buf = MALLOC(table_size);
 987         if (table_buf == NULL) {
 988                 ERROR("Failed to allocate %zu bytes for temporary lookup table",
 989                       table_size);
 990                 return WIMLIB_ERR_NOMEM;
 991         }
 992         table_buf_ptr = table_buf;
 993
 994         prev_res_offset_in_wim = ~0ULL;
 995         list_for_each_entry(lte, stream_list, lookup_table_list) {
 996
 997                 put_wim_lookup_table_entry(table_buf_ptr++,
 998                                            &lte->out_reshdr,
 999                                            part_number,
1000                                            lte->out_refcnt,
1001                                            lte->hash);
1002                 if (lte->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS &&
1003                     lte->out_res_offset_in_wim != prev_res_offset_in_wim)
1004                 {
1005                         /* Put the main resource entry for the pack.  */
1006
1007                         struct wim_reshdr reshdr;
1008
1009                         reshdr.offset_in_wim = lte->out_res_offset_in_wim;
1010                         reshdr.size_in_wim = lte->out_res_size_in_wim;
1011                         reshdr.uncompressed_size = WIM_PACK_MAGIC_NUMBER;
1012                         reshdr.flags = WIM_RESHDR_FLAG_PACKED_STREAMS;
1013
1014                         DEBUG("Putting main entry for pack: "
1015                               "size_in_wim=%"PRIu64", "
1016                               "offset_in_wim=%"PRIu64", "
1017                               "uncompressed_size=%"PRIu64,
1018                               reshdr.size_in_wim,
1019                               reshdr.offset_in_wim,
1020                               reshdr.uncompressed_size);
1021
1022                         put_wim_lookup_table_entry(table_buf_ptr++,
1023                                                    &reshdr,
1024                                                    part_number,
1025                                                    1, zero_hash);
1026                         prev_res_offset_in_wim = lte->out_res_offset_in_wim;
1027                 }
1028
1029         }
1030         wimlib_assert((u8*)table_buf_ptr - (u8*)table_buf == table_size);
1031
1032         /* Write the lookup table uncompressed.  Although wimlib can handle a
1033          * compressed lookup table, MS software cannot.  */
1034         ret = write_wim_resource_from_buffer(table_buf,
1035                                              table_size,
1036                                              WIM_RESHDR_FLAG_METADATA,
1037                                              out_fd,
1038                                              WIMLIB_COMPRESSION_TYPE_NONE,
1039                                              0,
1040                                              out_reshdr,
1041                                              NULL,
1042                                              write_resource_flags);
1043         FREE(table_buf);
1044         DEBUG("ret=%d", ret);
1045         return ret;
1046 }
1047
1048 int
1049 lte_zero_real_refcnt(struct wim_lookup_table_entry *lte, void *_ignore)
1050 {
1051         lte->real_refcnt = 0;
1052         return 0;
1053 }
1054
1055 int
1056 lte_zero_out_refcnt(struct wim_lookup_table_entry *lte, void *_ignore)
1057 {
1058         lte->out_refcnt = 0;
1059         return 0;
1060 }
1061
1062 int
1063 lte_free_extracted_file(struct wim_lookup_table_entry *lte, void *_ignore)
1064 {
1065         if (lte->extracted_file != NULL) {
1066                 FREE(lte->extracted_file);
1067                 lte->extracted_file = NULL;
1068         }
1069         return 0;
1070 }
1071
1072 /* Allocate a stream entry for the contents of the buffer, or re-use an existing
1073  * entry in @lookup_table for the same stream.  */
1074 struct wim_lookup_table_entry *
1075 new_stream_from_data_buffer(const void *buffer, size_t size,
1076                             struct wim_lookup_table *lookup_table)
1077 {
1078         u8 hash[SHA1_HASH_SIZE];
1079         struct wim_lookup_table_entry *lte, *existing_lte;
1080
1081         sha1_buffer(buffer, size, hash);
1082         existing_lte = lookup_stream(lookup_table, hash);
1083         if (existing_lte) {
1084                 wimlib_assert(existing_lte->size == size);
1085                 lte = existing_lte;
1086                 lte->refcnt++;
1087         } else {
1088                 void *buffer_copy;
1089                 lte = new_lookup_table_entry();
1090                 if (lte == NULL)
1091                         return NULL;
1092                 buffer_copy = memdup(buffer, size);
1093                 if (buffer_copy == NULL) {
1094                         free_lookup_table_entry(lte);
1095                         return NULL;
1096                 }
1097                 lte->resource_location  = RESOURCE_IN_ATTACHED_BUFFER;
1098                 lte->attached_buffer    = buffer_copy;
1099                 lte->size               = size;
1100                 copy_hash(lte->hash, hash);
1101                 lookup_table_insert(lookup_table, lte);
1102         }
1103         return lte;
1104 }
1105
1106 /* Calculate the SHA1 message digest of a stream and move it from the list of
1107  * unhashed streams to the stream lookup table, possibly joining it with an
1108  * existing lookup table entry for an identical stream.
1109  *
1110  * @lte:  An unhashed lookup table entry.
1111  * @lookup_table:  Lookup table for the WIM.
1112  * @lte_ret:  On success, write a pointer to the resulting lookup table
1113  *            entry to this location.  This will be the same as @lte
1114  *            if it was inserted into the lookup table, or different if
1115  *            a duplicate stream was found.
1116  *
1117  * Returns 0 on success; nonzero if there is an error reading the stream.
1118  */
1119 int
1120 hash_unhashed_stream(struct wim_lookup_table_entry *lte,
1121                      struct wim_lookup_table *lookup_table,
1122                      struct wim_lookup_table_entry **lte_ret)
1123 {
1124         int ret;
1125         struct wim_lookup_table_entry *duplicate_lte;
1126         struct wim_lookup_table_entry **back_ptr;
1127
1128         wimlib_assert(lte->unhashed);
1129
1130         /* back_ptr must be saved because @back_inode and @back_stream_id are in
1131          * union with the SHA1 message digest and will no longer be valid once
1132          * the SHA1 has been calculated. */
1133         back_ptr = retrieve_lte_pointer(lte);
1134
1135         ret = sha1_stream(lte);
1136         if (ret)
1137                 return ret;
1138
1139         /* Look for a duplicate stream */
1140         duplicate_lte = lookup_stream(lookup_table, lte->hash);
1141         list_del(&lte->unhashed_list);
1142         if (duplicate_lte) {
1143                 /* We have a duplicate stream.  Transfer the reference counts
1144                  * from this stream to the duplicate and update the reference to
1145                  * this stream (in an inode or ads_entry) to point to the
1146                  * duplicate.  The caller is responsible for freeing @lte if
1147                  * needed.  */
1148                 wimlib_assert(!(duplicate_lte->unhashed));
1149                 wimlib_assert(duplicate_lte->size == lte->size);
1150                 duplicate_lte->refcnt += lte->refcnt;
1151                 lte->refcnt = 0;
1152                 *back_ptr = duplicate_lte;
1153                 lte = duplicate_lte;
1154         } else {
1155                 /* No duplicate stream, so we need to insert this stream into
1156                  * the lookup table and treat it as a hashed stream. */
1157                 lookup_table_insert(lookup_table, lte);
1158                 lte->unhashed = 0;
1159         }
1160         *lte_ret = lte;
1161         return 0;
1162 }
1163
1164 void
1165 lte_to_wimlib_resource_entry(const struct wim_lookup_table_entry *lte,
1166                              struct wimlib_resource_entry *wentry)
1167 {
1168         memset(wentry, 0, sizeof(*wentry));
1169
1170         wentry->uncompressed_size = lte->size;
1171         if (lte->resource_location == RESOURCE_IN_WIM) {
1172                 wentry->part_number = lte->rspec->wim->hdr.part_number;
1173                 if (lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
1174                         wentry->compressed_size = 0;
1175                         wentry->offset = lte->offset_in_res;
1176                 } else {
1177                         wentry->compressed_size = lte->rspec->size_in_wim;
1178                         wentry->offset = lte->rspec->offset_in_wim;
1179                 }
1180                 wentry->raw_resource_offset_in_wim = lte->rspec->offset_in_wim;
1181                 /*wentry->raw_resource_uncompressed_size = lte->rspec->uncompressed_size;*/
1182                 wentry->raw_resource_compressed_size = lte->rspec->size_in_wim;
1183         }
1184         copy_hash(wentry->sha1_hash, lte->hash);
1185         wentry->reference_count = lte->refcnt;
1186         wentry->is_compressed = (lte->flags & WIM_RESHDR_FLAG_COMPRESSED) != 0;
1187         wentry->is_metadata = (lte->flags & WIM_RESHDR_FLAG_METADATA) != 0;
1188         wentry->is_free = (lte->flags & WIM_RESHDR_FLAG_FREE) != 0;
1189         wentry->is_spanned = (lte->flags & WIM_RESHDR_FLAG_SPANNED) != 0;
1190         wentry->packed = (lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS) != 0;
1191 }
1192
1193 struct iterate_lte_context {
1194         wimlib_iterate_lookup_table_callback_t cb;
1195         void *user_ctx;
1196 };
1197
1198 static int
1199 do_iterate_lte(struct wim_lookup_table_entry *lte, void *_ctx)
1200 {
1201         struct iterate_lte_context *ctx = _ctx;
1202         struct wimlib_resource_entry entry;
1203
1204         lte_to_wimlib_resource_entry(lte, &entry);
1205         return (*ctx->cb)(&entry, ctx->user_ctx);
1206 }
1207
1208 /* API function documented in wimlib.h  */
1209 WIMLIBAPI int
1210 wimlib_iterate_lookup_table(WIMStruct *wim, int flags,
1211                             wimlib_iterate_lookup_table_callback_t cb,
1212                             void *user_ctx)
1213 {
1214         if (flags != 0)
1215                 return WIMLIB_ERR_INVALID_PARAM;
1216
1217         struct iterate_lte_context ctx = {
1218                 .cb = cb,
1219                 .user_ctx = user_ctx,
1220         };
1221         if (wim->hdr.part_number == 1) {
1222                 int ret;
1223                 for (int i = 0; i < wim->hdr.image_count; i++) {
1224                         ret = do_iterate_lte(wim->image_metadata[i]->metadata_lte,
1225                                              &ctx);
1226                         if (ret)
1227                                 return ret;
1228                 }
1229         }
1230         return for_lookup_table_entry(wim->lookup_table, do_iterate_lte, &ctx);
1231 }