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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, 2014 Eric Biggers
  10  *
  11  * This file is free software; you can redistribute it and/or modify it under
  12  * the terms of the GNU Lesser General Public License as published by the Free
  13  * Software Foundation; either version 3 of the License, or (at your option) any
  14  * later version.
  15  *
  16  * This file is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  19  * details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public License
  22  * along with this file; if not, see http://www.gnu.org/licenses/.
  23  */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #  include "config.h"
  27 #endif
  28
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include <unistd.h> /* for unlink()  */
  32
  33 #include "wimlib/assert.h"
  34 #include "wimlib/endianness.h"
  35 #include "wimlib/error.h"
  36 #include "wimlib/lookup_table.h"
  37 #include "wimlib/metadata.h"
  38 #include "wimlib/ntfs_3g.h"
  39 #include "wimlib/resource.h"
  40 #include "wimlib/unaligned.h"
  41 #include "wimlib/util.h"
  42 #include "wimlib/write.h"
  43
  44 /* WIM lookup table:
  45  *
  46  * This is a logical mapping from SHA1 message digests to the data streams
  47  * contained in a WIM.
  48  *
  49  * Here it is implemented as a hash table.
  50  *
  51  * Note: Everything will break horribly if there is a SHA1 collision.
  52  */
  53 struct wim_lookup_table {
  54         struct hlist_head *array;
  55         size_t num_entries;
  56         size_t capacity;
  57 };
  58
  59 struct wim_lookup_table *
  60 new_lookup_table(size_t capacity)
  61 {
  62         struct wim_lookup_table *table;
  63         struct hlist_head *array;
  64
  65         table = MALLOC(sizeof(struct wim_lookup_table));
  66         if (table == NULL)
  67                 goto oom;
  68
  69         array = CALLOC(capacity, sizeof(array[0]));
  70         if (array == NULL) {
  71                 FREE(table);
  72                 goto oom;
  73         }
  74
  75         table->num_entries = 0;
  76         table->capacity = capacity;
  77         table->array = array;
  78         return table;
  79
  80 oom:
  81         ERROR("Failed to allocate memory for lookup table "
  82               "with capacity %zu", capacity);
  83         return NULL;
  84 }
  85
  86 static int
  87 do_free_lookup_table_entry(struct wim_lookup_table_entry *entry, void *ignore)
  88 {
  89         free_lookup_table_entry(entry);
  90         return 0;
  91 }
  92
  93 void
  94 free_lookup_table(struct wim_lookup_table *table)
  95 {
  96         if (table) {
  97                 for_lookup_table_entry(table, do_free_lookup_table_entry, NULL);
  98                 FREE(table->array);
  99                 FREE(table);
 100         }
 101 }
 102
 103 struct wim_lookup_table_entry *
 104 new_lookup_table_entry(void)
 105 {
 106         struct wim_lookup_table_entry *lte;
 107
 108         lte = CALLOC(1, sizeof(struct wim_lookup_table_entry));
 109         if (lte == NULL)
 110                 return NULL;
 111
 112         lte->refcnt = 1;
 113
 114         /* lte->resource_location = RESOURCE_NONEXISTENT  */
 115         BUILD_BUG_ON(RESOURCE_NONEXISTENT != 0);
 116
 117         return lte;
 118 }
 119
 120 struct wim_lookup_table_entry *
 121 clone_lookup_table_entry(const struct wim_lookup_table_entry *old)
 122 {
 123         struct wim_lookup_table_entry *new;
 124
 125         new = memdup(old, sizeof(struct wim_lookup_table_entry));
 126         if (new == NULL)
 127                 return NULL;
 128
 129         switch (new->resource_location) {
 130         case RESOURCE_IN_WIM:
 131                 list_add(&new->rspec_node, &new->rspec->stream_list);
 132                 break;
 133
 134         case RESOURCE_IN_FILE_ON_DISK:
 135 #ifdef __WIN32__
 136         case RESOURCE_IN_WINNT_FILE_ON_DISK:
 137         case RESOURCE_WIN32_ENCRYPTED:
 138 #endif
 139 #ifdef WITH_FUSE
 140         case RESOURCE_IN_STAGING_FILE:
 141                 BUILD_BUG_ON((void*)&old->file_on_disk !=
 142                              (void*)&old->staging_file_name);
 143 #endif
 144                 new->file_on_disk = TSTRDUP(old->file_on_disk);
 145                 if (new->file_on_disk == NULL)
 146                         goto out_free;
 147                 break;
 148         case RESOURCE_IN_ATTACHED_BUFFER:
 149                 new->attached_buffer = memdup(old->attached_buffer, old->size);
 150                 if (new->attached_buffer == NULL)
 151                         goto out_free;
 152                 break;
 153 #ifdef WITH_NTFS_3G
 154         case RESOURCE_IN_NTFS_VOLUME:
 155                 if (old->ntfs_loc) {
 156                         struct ntfs_location *loc;
 157                         loc = memdup(old->ntfs_loc, sizeof(struct ntfs_location));
 158                         if (loc == NULL)
 159                                 goto out_free;
 160                         loc->path = NULL;
 161                         loc->stream_name = NULL;
 162                         new->ntfs_loc = loc;
 163                         loc->path = STRDUP(old->ntfs_loc->path);
 164                         if (loc->path == NULL)
 165                                 goto out_free;
 166                         if (loc->stream_name_nchars != 0) {
 167                                 loc->stream_name = memdup(old->ntfs_loc->stream_name,
 168                                                           loc->stream_name_nchars * 2);
 169                                 if (loc->stream_name == NULL)
 170                                         goto out_free;
 171                         }
 172                 }
 173                 break;
 174 #endif
 175         default:
 176                 break;
 177         }
 178         return new;
 179
 180 out_free:
 181         free_lookup_table_entry(new);
 182         return NULL;
 183 }
 184
 185 void
 186 lte_put_resource(struct wim_lookup_table_entry *lte)
 187 {
 188         switch (lte->resource_location) {
 189         case RESOURCE_IN_WIM:
 190                 list_del(&lte->rspec_node);
 191                 if (list_empty(&lte->rspec->stream_list))
 192                         FREE(lte->rspec);
 193                 break;
 194         case RESOURCE_IN_FILE_ON_DISK:
 195 #ifdef __WIN32__
 196         case RESOURCE_IN_WINNT_FILE_ON_DISK:
 197         case RESOURCE_WIN32_ENCRYPTED:
 198 #endif
 199 #ifdef WITH_FUSE
 200         case RESOURCE_IN_STAGING_FILE:
 201                 BUILD_BUG_ON((void*)&lte->file_on_disk !=
 202                              (void*)&lte->staging_file_name);
 203 #endif
 204         case RESOURCE_IN_ATTACHED_BUFFER:
 205                 BUILD_BUG_ON((void*)&lte->file_on_disk !=
 206                              (void*)&lte->attached_buffer);
 207                 FREE(lte->file_on_disk);
 208                 break;
 209 #ifdef WITH_NTFS_3G
 210         case RESOURCE_IN_NTFS_VOLUME:
 211                 if (lte->ntfs_loc) {
 212                         FREE(lte->ntfs_loc->path);
 213                         FREE(lte->ntfs_loc->stream_name);
 214                         FREE(lte->ntfs_loc);
 215                 }
 216                 break;
 217 #endif
 218         default:
 219                 break;
 220         }
 221 }
 222
 223 void
 224 free_lookup_table_entry(struct wim_lookup_table_entry *lte)
 225 {
 226         if (lte) {
 227                 lte_put_resource(lte);
 228                 FREE(lte);
 229         }
 230 }
 231
 232 /* Should this stream be retained even if it has no references?  */
 233 static bool
 234 should_retain_lte(const struct wim_lookup_table_entry *lte)
 235 {
 236         return lte->resource_location == RESOURCE_IN_WIM;
 237 }
 238
 239 static void
 240 finalize_lte(struct wim_lookup_table_entry *lte)
 241 {
 242         if (!should_retain_lte(lte))
 243                 free_lookup_table_entry(lte);
 244 }
 245
 246 /*
 247  * Decrements the reference count of the single-instance stream @lte, which must
 248  * be inserted in the stream lookup table @table.
 249  *
 250  * If the stream's reference count reaches 0, we may unlink it from @table and
 251  * free it.  However, we retain streams with 0 reference count that originated
 252  * from WIM files (RESOURCE_IN_WIM).  We do this for two reasons:
 253  *
 254  * 1. This prevents information about valid streams in a WIM file --- streams
 255  *    which will continue to be present after appending to the WIM file --- from
 256  *    being lost merely because we dropped all references to them.
 257  *
 258  * 2. Stream reference counts we read from WIM files can't be trusted.  It's
 259  *    possible that a WIM has reference counts that are too low; WIMGAPI
 260  *    sometimes creates WIMs where this is the case.  It's also possible that
 261  *    streams have been referenced from an external WIM; those streams can
 262  *    potentially have any reference count at all, either lower or higher than
 263  *    would be expected for this WIM ("this WIM" meaning the owner of @table) if
 264  *    it were a standalone WIM.
 265  *
 266  * So we can't take the reference counts too seriously.  But at least, we do
 267  * recalculate by default when writing a new WIM file.
 268  */
 269 void
 270 lte_decrement_refcnt(struct wim_lookup_table_entry *lte,
 271                      struct wim_lookup_table *table)
 272 {
 273         if (unlikely(lte->refcnt == 0))  /* See comment above  */
 274                 return;
 275
 276         if (--lte->refcnt == 0) {
 277                 if (lte->unhashed) {
 278                         list_del(&lte->unhashed_list);
 279                 #ifdef WITH_FUSE
 280                         /* If the stream has been extracted to a staging file
 281                          * for a FUSE mount, unlink the staging file.  (Note
 282                          * that there still may be open file descriptors to it.)
 283                          * */
 284                         if (lte->resource_location == RESOURCE_IN_STAGING_FILE)
 285                                 unlinkat(lte->staging_dir_fd,
 286                                          lte->staging_file_name, 0);
 287                 #endif
 288                 } else {
 289                         if (!should_retain_lte(lte))
 290                                 lookup_table_unlink(table, lte);
 291                 }
 292
 293                 /* If FUSE mounts are enabled, we don't actually free the entry
 294                  * until the last file descriptor has been closed by
 295                  * lte_decrement_num_opened_fds().  */
 296 #ifdef WITH_FUSE
 297                 if (lte->num_opened_fds == 0)
 298 #endif
 299                         finalize_lte(lte);
 300         }
 301 }
 302
 303 #ifdef WITH_FUSE
 304 void
 305 lte_decrement_num_opened_fds(struct wim_lookup_table_entry *lte)
 306 {
 307         wimlib_assert(lte->num_opened_fds != 0);
 308
 309         if (--lte->num_opened_fds == 0 && lte->refcnt == 0)
 310                 finalize_lte(lte);
 311 }
 312 #endif
 313
 314 static void
 315 lookup_table_insert_raw(struct wim_lookup_table *table,
 316                         struct wim_lookup_table_entry *lte)
 317 {
 318         size_t i = lte->hash_short % table->capacity;
 319
 320         hlist_add_head(&lte->hash_list, &table->array[i]);
 321 }
 322
 323 static void
 324 enlarge_lookup_table(struct wim_lookup_table *table)
 325 {
 326         size_t old_capacity, new_capacity;
 327         struct hlist_head *old_array, *new_array;
 328         struct wim_lookup_table_entry *lte;
 329         struct hlist_node *cur, *tmp;
 330         size_t i;
 331
 332         old_capacity = table->capacity;
 333         new_capacity = old_capacity * 2;
 334         new_array = CALLOC(new_capacity, sizeof(struct hlist_head));
 335         if (new_array == NULL)
 336                 return;
 337         old_array = table->array;
 338         table->array = new_array;
 339         table->capacity = new_capacity;
 340
 341         for (i = 0; i < old_capacity; i++) {
 342                 hlist_for_each_entry_safe(lte, cur, tmp, &old_array[i], hash_list) {
 343                         hlist_del(&lte->hash_list);
 344                         lookup_table_insert_raw(table, lte);
 345                 }
 346         }
 347         FREE(old_array);
 348 }
 349
 350 /* Inserts an entry into the lookup table.  */
 351 void
 352 lookup_table_insert(struct wim_lookup_table *table,
 353                     struct wim_lookup_table_entry *lte)
 354 {
 355         lookup_table_insert_raw(table, lte);
 356         if (++table->num_entries > table->capacity)
 357                 enlarge_lookup_table(table);
 358 }
 359
 360 /* Unlinks a lookup table entry from the table; does not free it.  */
 361 void
 362 lookup_table_unlink(struct wim_lookup_table *table,
 363                     struct wim_lookup_table_entry *lte)
 364 {
 365         wimlib_assert(!lte->unhashed);
 366         wimlib_assert(table->num_entries != 0);
 367
 368         hlist_del(&lte->hash_list);
 369         table->num_entries--;
 370 }
 371
 372 /* Given a SHA1 message digest, return the corresponding entry in the WIM's
 373  * lookup table, or NULL if there is none.  */
 374 struct wim_lookup_table_entry *
 375 lookup_stream(const struct wim_lookup_table *table, const u8 hash[])
 376 {
 377         size_t i;
 378         struct wim_lookup_table_entry *lte;
 379         struct hlist_node *pos;
 380
 381         i = load_size_t_unaligned(hash) % table->capacity;
 382         hlist_for_each_entry(lte, pos, &table->array[i], hash_list)
 383                 if (hashes_equal(hash, lte->hash))
 384                         return lte;
 385         return NULL;
 386 }
 387
 388 /* Calls a function on all the entries in the WIM lookup table.  Stop early and
 389  * return nonzero if any call to the function returns nonzero. */
 390 int
 391 for_lookup_table_entry(struct wim_lookup_table *table,
 392                        int (*visitor)(struct wim_lookup_table_entry *, void *),
 393                        void *arg)
 394 {
 395         struct wim_lookup_table_entry *lte;
 396         struct hlist_node *pos, *tmp;
 397         int ret;
 398
 399         for (size_t i = 0; i < table->capacity; i++) {
 400                 hlist_for_each_entry_safe(lte, pos, tmp, &table->array[i],
 401                                           hash_list)
 402                 {
 403                         ret = visitor(lte, arg);
 404                         if (ret)
 405                                 return ret;
 406                 }
 407         }
 408         return 0;
 409 }
 410
 411 /* qsort() callback that sorts streams (represented by `struct
 412  * wim_lookup_table_entry's) into an order optimized for reading.
 413  *
 414  * Sorting is done primarily by resource location, then secondarily by a
 415  * per-resource location order.  For example, resources in WIM files are sorted
 416  * primarily by part number, then secondarily by offset, as to implement optimal
 417  * reading of either a standalone or split WIM.  */
 418 static int
 419 cmp_streams_by_sequential_order(const void *p1, const void *p2)
 420 {
 421         const struct wim_lookup_table_entry *lte1, *lte2;
 422         int v;
 423         WIMStruct *wim1, *wim2;
 424
 425         lte1 = *(const struct wim_lookup_table_entry**)p1;
 426         lte2 = *(const struct wim_lookup_table_entry**)p2;
 427
 428         v = (int)lte1->resource_location - (int)lte2->resource_location;
 429
 430         /* Different resource locations?  */
 431         if (v)
 432                 return v;
 433
 434         switch (lte1->resource_location) {
 435         case RESOURCE_IN_WIM:
 436                 wim1 = lte1->rspec->wim;
 437                 wim2 = lte2->rspec->wim;
 438
 439                 /* Different (possibly split) WIMs?  */
 440                 if (wim1 != wim2) {
 441                         v = memcmp(wim1->hdr.guid, wim2->hdr.guid, WIM_GUID_LEN);
 442                         if (v)
 443                                 return v;
 444                 }
 445
 446                 /* Different part numbers in the same WIM?  */
 447                 v = (int)wim1->hdr.part_number - (int)wim2->hdr.part_number;
 448                 if (v)
 449                         return v;
 450
 451                 if (lte1->rspec->offset_in_wim != lte2->rspec->offset_in_wim)
 452                         return cmp_u64(lte1->rspec->offset_in_wim,
 453                                        lte2->rspec->offset_in_wim);
 454
 455                 return cmp_u64(lte1->offset_in_res, lte2->offset_in_res);
 456
 457         case RESOURCE_IN_FILE_ON_DISK:
 458 #ifdef WITH_FUSE
 459         case RESOURCE_IN_STAGING_FILE:
 460 #endif
 461 #ifdef __WIN32__
 462         case RESOURCE_IN_WINNT_FILE_ON_DISK:
 463         case RESOURCE_WIN32_ENCRYPTED:
 464 #endif
 465                 /* Compare files by path: just a heuristic that will place files
 466                  * in the same directory next to each other.  */
 467                 return tstrcmp(lte1->file_on_disk, lte2->file_on_disk);
 468 #ifdef WITH_NTFS_3G
 469         case RESOURCE_IN_NTFS_VOLUME:
 470                 return tstrcmp(lte1->ntfs_loc->path, lte2->ntfs_loc->path);
 471 #endif
 472         default:
 473                 /* No additional sorting order defined for this resource
 474                  * location (e.g. RESOURCE_IN_ATTACHED_BUFFER); simply compare
 475                  * everything equal to each other.  */
 476                 return 0;
 477         }
 478 }
 479
 480 int
 481 sort_stream_list(struct list_head *stream_list,
 482                  size_t list_head_offset,
 483                  int (*compar)(const void *, const void*))
 484 {
 485         struct list_head *cur;
 486         struct wim_lookup_table_entry **array;
 487         size_t i;
 488         size_t array_size;
 489         size_t num_streams = 0;
 490
 491         list_for_each(cur, stream_list)
 492                 num_streams++;
 493
 494         if (num_streams <= 1)
 495                 return 0;
 496
 497         array_size = num_streams * sizeof(array[0]);
 498         array = MALLOC(array_size);
 499         if (array == NULL)
 500                 return WIMLIB_ERR_NOMEM;
 501
 502         cur = stream_list->next;
 503         for (i = 0; i < num_streams; i++) {
 504                 array[i] = (struct wim_lookup_table_entry*)((u8*)cur -
 505                                                             list_head_offset);
 506                 cur = cur->next;
 507         }
 508
 509         qsort(array, num_streams, sizeof(array[0]), compar);
 510
 511         INIT_LIST_HEAD(stream_list);
 512         for (i = 0; i < num_streams; i++) {
 513                 list_add_tail((struct list_head*)
 514                                ((u8*)array[i] + list_head_offset),
 515                               stream_list);
 516         }
 517         FREE(array);
 518         return 0;
 519 }
 520
 521 /* Sort the specified list of streams in an order optimized for reading.  */
 522 int
 523 sort_stream_list_by_sequential_order(struct list_head *stream_list,
 524                                      size_t list_head_offset)
 525 {
 526         return sort_stream_list(stream_list, list_head_offset,
 527                                 cmp_streams_by_sequential_order);
 528 }
 529
 530
 531 static int
 532 add_lte_to_array(struct wim_lookup_table_entry *lte,
 533                  void *_pp)
 534 {
 535         struct wim_lookup_table_entry ***pp = _pp;
 536         *(*pp)++ = lte;
 537         return 0;
 538 }
 539
 540 /* Iterate through the lookup table entries, but first sort them by stream
 541  * offset in the WIM.  Caution: this is intended to be used when the stream
 542  * offset field has actually been set. */
 543 int
 544 for_lookup_table_entry_pos_sorted(struct wim_lookup_table *table,
 545                                   int (*visitor)(struct wim_lookup_table_entry *,
 546                                                  void *),
 547                                   void *arg)
 548 {
 549         struct wim_lookup_table_entry **lte_array, **p;
 550         size_t num_streams = table->num_entries;
 551         int ret;
 552
 553         lte_array = MALLOC(num_streams * sizeof(lte_array[0]));
 554         if (!lte_array)
 555                 return WIMLIB_ERR_NOMEM;
 556         p = lte_array;
 557         for_lookup_table_entry(table, add_lte_to_array, &p);
 558
 559         wimlib_assert(p == lte_array + num_streams);
 560
 561         qsort(lte_array, num_streams, sizeof(lte_array[0]),
 562               cmp_streams_by_sequential_order);
 563         ret = 0;
 564         for (size_t i = 0; i < num_streams; i++) {
 565                 ret = visitor(lte_array[i], arg);
 566                 if (ret)
 567                         break;
 568         }
 569         FREE(lte_array);
 570         return ret;
 571 }
 572
 573 /* On-disk format of a WIM lookup table entry (stream entry). */
 574 struct wim_lookup_table_entry_disk {
 575         /* Size, offset, and flags of the stream.  */
 576         struct wim_reshdr_disk reshdr;
 577
 578         /* Which part of the split WIM this stream is in; indexed from 1. */
 579         le16 part_number;
 580
 581         /* Reference count of this stream over all WIM images.  (But see comment
 582          * above lte_decrement_refcnt().)  */
 583         le32 refcnt;
 584
 585         /* SHA1 message digest of the uncompressed data of this stream, or
 586          * optionally all zeroes if this stream is of zero length. */
 587         u8 hash[SHA1_HASH_SIZE];
 588 } _packed_attribute;
 589
 590 #define WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE 50
 591
 592 /* Given a nonempty run of consecutive lookup table entries with the
 593  * PACKED_STREAMS flag set, count how many specify resources (as opposed to
 594  * streams within those resources).
 595  *
 596  * Returns the resulting count.  */
 597 static size_t
 598 count_subpacks(const struct wim_lookup_table_entry_disk *entries, size_t max)
 599 {
 600         size_t count = 0;
 601         do {
 602                 struct wim_reshdr reshdr;
 603
 604                 get_wim_reshdr(&(entries++)->reshdr, &reshdr);
 605
 606                 if (!(reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS)) {
 607                         /* Run was terminated by a stand-alone stream entry.  */
 608                         break;
 609                 }
 610
 611                 if (reshdr.uncompressed_size == WIM_PACK_MAGIC_NUMBER) {
 612                         /* This is a resource entry.  */
 613                         count++;
 614                 }
 615         } while (--max);
 616         return count;
 617 }
 618
 619 /* Given a run of consecutive lookup table entries with the PACKED_STREAMS flag
 620  * set and having @num_subpacks resource entries, load resource information from
 621  * them into the resource specifications in the @subpacks array.
 622  *
 623  * Returns 0 on success, or a nonzero error code on failure.  */
 624 static int
 625 do_load_subpack_info(WIMStruct *wim, struct wim_resource_spec **subpacks,
 626                      size_t num_subpacks,
 627                      const struct wim_lookup_table_entry_disk *entries)
 628 {
 629         for (size_t i = 0; i < num_subpacks; i++) {
 630                 struct wim_reshdr reshdr;
 631                 struct alt_chunk_table_header_disk hdr;
 632                 struct wim_resource_spec *rspec;
 633                 int ret;
 634
 635                 /* Advance to next resource entry.  */
 636
 637                 do {
 638                         get_wim_reshdr(&(entries++)->reshdr, &reshdr);
 639                 } while (reshdr.uncompressed_size != WIM_PACK_MAGIC_NUMBER);
 640
 641                 rspec = subpacks[i];
 642
 643                 wim_res_hdr_to_spec(&reshdr, wim, rspec);
 644
 645                 /* For packed resources, the uncompressed size, compression
 646                  * type, and chunk size are stored in the resource itself, not
 647                  * in the lookup table.  */
 648
 649                 ret = full_pread(&wim->in_fd, &hdr,
 650                                  sizeof(hdr), reshdr.offset_in_wim);
 651                 if (ret) {
 652                         ERROR("Failed to read header of packed resource "
 653                               "(offset_in_wim=%"PRIu64")",
 654                               reshdr.offset_in_wim);
 655                         return ret;
 656                 }
 657
 658                 rspec->uncompressed_size = le64_to_cpu(hdr.res_usize);
 659
 660                 /* Compression format numbers must be the same as in
 661                  * WIMGAPI to be compatible here.  */
 662                 BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_NONE != 0);
 663                 BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_XPRESS != 1);
 664                 BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZX != 2);
 665                 BUILD_BUG_ON(WIMLIB_COMPRESSION_TYPE_LZMS != 3);
 666                 rspec->compression_type = le32_to_cpu(hdr.compression_format);
 667
 668                 rspec->chunk_size = le32_to_cpu(hdr.chunk_size);
 669
 670                 DEBUG("Subpack %zu/%zu: %"PRIu64" => %"PRIu64" "
 671                       "(%"TS"/%"PRIu32") @ +%"PRIu64"",
 672                       i + 1, num_subpacks,
 673                       rspec->uncompressed_size,
 674                       rspec->size_in_wim,
 675                       wimlib_get_compression_type_string(rspec->compression_type),
 676                       rspec->chunk_size,
 677                       rspec->offset_in_wim);
 678
 679         }
 680         return 0;
 681 }
 682
 683 /* Given a nonempty run of consecutive lookup table entries with the
 684  * PACKED_STREAMS flag set, allocate a 'struct wim_resource_spec' for each
 685  * resource within that run.
 686  *
 687  * Returns 0 on success, or a nonzero error code on failure.
 688  * Returns the pointers and count in *subpacks_ret and *num_subpacks_ret.
 689  */
 690 static int
 691 load_subpack_info(WIMStruct *wim,
 692                   const struct wim_lookup_table_entry_disk *entries,
 693                   size_t num_remaining_entries,
 694                   struct wim_resource_spec ***subpacks_ret,
 695                   size_t *num_subpacks_ret)
 696 {
 697         size_t num_subpacks;
 698         struct wim_resource_spec **subpacks;
 699         size_t i;
 700         int ret;
 701
 702         num_subpacks = count_subpacks(entries, num_remaining_entries);
 703         subpacks = CALLOC(num_subpacks, sizeof(subpacks[0]));
 704         if (!subpacks)
 705                 return WIMLIB_ERR_NOMEM;
 706
 707         for (i = 0; i < num_subpacks; i++) {
 708                 subpacks[i] = MALLOC(sizeof(struct wim_resource_spec));
 709                 if (!subpacks[i]) {
 710                         ret = WIMLIB_ERR_NOMEM;
 711                         goto out_free_subpacks;
 712                 }
 713         }
 714
 715         ret = do_load_subpack_info(wim, subpacks, num_subpacks, entries);
 716         if (ret)
 717                 goto out_free_subpacks;
 718
 719         *subpacks_ret = subpacks;
 720         *num_subpacks_ret = num_subpacks;
 721         return 0;
 722
 723 out_free_subpacks:
 724         for (i = 0; i < num_subpacks; i++)
 725                 FREE(subpacks[i]);
 726         FREE(subpacks);
 727         return ret;
 728 }
 729
 730 /* Given a 'struct wim_lookup_table_entry' allocated for a stream entry with
 731  * PACKED_STREAMS set, try to bind it to a subpack of the current PACKED_STREAMS
 732  * run.  */
 733 static int
 734 bind_stream_to_subpack(const struct wim_reshdr *reshdr,
 735                        struct wim_lookup_table_entry *stream,
 736                        struct wim_resource_spec **subpacks,
 737                        size_t num_subpacks)
 738 {
 739         u64 offset = reshdr->offset_in_wim;
 740
 741         /* XXX: This linear search will be slow in the degenerate case where the
 742          * number of subpacks is huge.  */
 743         stream->size = reshdr->size_in_wim;
 744         stream->flags = reshdr->flags;
 745         for (size_t i = 0; i < num_subpacks; i++) {
 746                 if (offset + stream->size <= subpacks[i]->uncompressed_size) {
 747                         stream->offset_in_res = offset;
 748                         lte_bind_wim_resource_spec(stream, subpacks[i]);
 749                         return 0;
 750                 }
 751                 offset -= subpacks[i]->uncompressed_size;
 752         }
 753         ERROR("Packed stream could not be assigned to any resource");
 754         return WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 755 }
 756
 757 static void
 758 free_subpack_info(struct wim_resource_spec **subpacks, size_t num_subpacks)
 759 {
 760         if (subpacks) {
 761                 for (size_t i = 0; i < num_subpacks; i++)
 762                         if (list_empty(&subpacks[i]->stream_list))
 763                                 FREE(subpacks[i]);
 764                 FREE(subpacks);
 765         }
 766 }
 767
 768 static int
 769 cmp_streams_by_offset_in_res(const void *p1, const void *p2)
 770 {
 771         const struct wim_lookup_table_entry *lte1, *lte2;
 772
 773         lte1 = *(const struct wim_lookup_table_entry**)p1;
 774         lte2 = *(const struct wim_lookup_table_entry**)p2;
 775
 776         return cmp_u64(lte1->offset_in_res, lte2->offset_in_res);
 777 }
 778
 779 /* Validate the size and location of a WIM resource.  */
 780 static int
 781 validate_resource(struct wim_resource_spec *rspec)
 782 {
 783         struct wim_lookup_table_entry *lte;
 784         bool out_of_order;
 785         u64 expected_next_offset;
 786         int ret;
 787
 788         /* Verify that the resource itself has a valid offset and size.  */
 789         if (rspec->offset_in_wim + rspec->size_in_wim < rspec->size_in_wim)
 790                 goto invalid_due_to_overflow;
 791
 792         /* Verify that each stream in the resource has a valid offset and size.
 793          */
 794         expected_next_offset = 0;
 795         out_of_order = false;
 796         list_for_each_entry(lte, &rspec->stream_list, rspec_node) {
 797                 if (lte->offset_in_res + lte->size < lte->size ||
 798                     lte->offset_in_res + lte->size > rspec->uncompressed_size)
 799                         goto invalid_due_to_overflow;
 800
 801                 if (lte->offset_in_res >= expected_next_offset)
 802                         expected_next_offset = lte->offset_in_res + lte->size;
 803                 else
 804                         out_of_order = true;
 805         }
 806
 807         /* If the streams were not located at strictly increasing positions (not
 808          * allowing for overlap), sort them.  Then make sure that none overlap.
 809          */
 810         if (out_of_order) {
 811                 ret = sort_stream_list(&rspec->stream_list,
 812                                        offsetof(struct wim_lookup_table_entry,
 813                                                 rspec_node),
 814                                        cmp_streams_by_offset_in_res);
 815                 if (ret)
 816                         return ret;
 817
 818                 expected_next_offset = 0;
 819                 list_for_each_entry(lte, &rspec->stream_list, rspec_node) {
 820                         if (lte->offset_in_res >= expected_next_offset)
 821                                 expected_next_offset = lte->offset_in_res + lte->size;
 822                         else
 823                                 goto invalid_due_to_overlap;
 824                 }
 825         }
 826
 827         return 0;
 828
 829 invalid_due_to_overflow:
 830         ERROR("Invalid resource entry (offset overflow)");
 831         return WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 832
 833 invalid_due_to_overlap:
 834         ERROR("Invalid resource entry (streams in packed resource overlap)");
 835         return WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
 836 }
 837
 838 static int
 839 finish_subpacks(struct wim_resource_spec **subpacks, size_t num_subpacks)
 840 {
 841         int ret = 0;
 842         for (size_t i = 0; i < num_subpacks; i++) {
 843                 ret = validate_resource(subpacks[i]);
 844                 if (ret)
 845                         break;
 846         }
 847         free_subpack_info(subpacks, num_subpacks);
 848         return ret;
 849 }
 850
 851 /*
 852  * Reads the lookup table from a WIM file.  Usually, each entry specifies a
 853  * stream that the WIM file contains, along with its location and SHA1 message
 854  * digest.
 855  *
 856  * Saves lookup table entries for non-metadata streams in a hash table (set to
 857  * wim->lookup_table), and saves the metadata entry for each image in a special
 858  * per-image location (the wim->image_metadata array).
 859  *
 860  * This works for both version WIM_VERSION_DEFAULT (68864) and version
 861  * WIM_VERSION_PACKED_STREAMS (3584) WIMs.  In the latter, a consecutive run of
 862  * lookup table entries that all have flag WIM_RESHDR_FLAG_PACKED_STREAMS (0x10)
 863  * set is a "packed run".  A packed run logically contains zero or more
 864  * resources, each of which logically contains zero or more streams.
 865  * Physically, in such a run, a "lookup table entry" with uncompressed size
 866  * WIM_PACK_MAGIC_NUMBER (0x100000000) specifies a resource, whereas any other
 867  * entry specifies a stream.  Within such a run, stream entries and resource
 868  * entries need not be in any particular order, except that the order of the
 869  * resource entries is important, as it affects how streams are assigned to
 870  * resources.  See the code for details.
 871  *
 872  * Possible return values:
 873  *      WIMLIB_ERR_SUCCESS (0)
 874  *      WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY
 875  *      WIMLIB_ERR_NOMEM
 876  *
 877  *      Or an error code caused by failure to read the lookup table from the WIM
 878  *      file.
 879  */
 880 int
 881 read_wim_lookup_table(WIMStruct *wim)
 882 {
 883         int ret;
 884         size_t num_entries;
 885         void *buf = NULL;
 886         struct wim_lookup_table *table = NULL;
 887         struct wim_lookup_table_entry *cur_entry = NULL;
 888         size_t num_duplicate_entries = 0;
 889         size_t num_wrong_part_entries = 0;
 890         u32 image_index = 0;
 891         struct wim_resource_spec **cur_subpacks = NULL;
 892         size_t cur_num_subpacks = 0;
 893
 894         DEBUG("Reading lookup table.");
 895
 896         /* Sanity check: lookup table entries are 50 bytes each.  */
 897         BUILD_BUG_ON(sizeof(struct wim_lookup_table_entry_disk) !=
 898                      WIM_LOOKUP_TABLE_ENTRY_DISK_SIZE);
 899
 900         /* Calculate the number of entries in the lookup table.  */
 901         num_entries = wim->hdr.lookup_table_reshdr.uncompressed_size /
 902                       sizeof(struct wim_lookup_table_entry_disk);
 903
 904         /* Read the lookup table into a buffer.  */
 905         ret = wim_reshdr_to_data(&wim->hdr.lookup_table_reshdr, wim, &buf);
 906         if (ret)
 907                 goto out;
 908
 909         /* Allocate a hash table to map SHA1 message digests into stream
 910          * specifications.  This is the in-memory "lookup table".  */
 911         table = new_lookup_table(num_entries * 2 + 1);
 912         if (!table)
 913                 goto oom;
 914
 915         /* Allocate and initalize stream entries ('struct
 916          * wim_lookup_table_entry's) from the raw lookup table buffer.  Each of
 917          * these entries will point to a 'struct wim_resource_spec' that
 918          * describes the underlying resource.  In WIMs with version number
 919          * WIM_VERSION_PACKED_STREAMS, a resource may contain multiple streams.
 920          */
 921         for (size_t i = 0; i < num_entries; i++) {
 922                 const struct wim_lookup_table_entry_disk *disk_entry =
 923                         &((const struct wim_lookup_table_entry_disk*)buf)[i];
 924                 struct wim_reshdr reshdr;
 925                 u16 part_number;
 926
 927                 /* Get the resource header  */
 928                 get_wim_reshdr(&disk_entry->reshdr, &reshdr);
 929
 930                 DEBUG("reshdr: size_in_wim=%"PRIu64", "
 931                       "uncompressed_size=%"PRIu64", "
 932                       "offset_in_wim=%"PRIu64", "
 933                       "flags=0x%02x",
 934                       reshdr.size_in_wim, reshdr.uncompressed_size,
 935                       reshdr.offset_in_wim, reshdr.flags);
 936
 937                 /* Ignore PACKED_STREAMS flag if it isn't supposed to be used in
 938                  * this WIM version.  */
 939                 if (wim->hdr.wim_version == WIM_VERSION_DEFAULT)
 940                         reshdr.flags &= ~WIM_RESHDR_FLAG_PACKED_STREAMS;
 941
 942                 /* Allocate a new 'struct wim_lookup_table_entry'.  */
 943                 cur_entry = new_lookup_table_entry();
 944                 if (!cur_entry)
 945                         goto oom;
 946
 947                 /* Get the part number, reference count, and hash.  */
 948                 part_number = le16_to_cpu(disk_entry->part_number);
 949                 cur_entry->refcnt = le32_to_cpu(disk_entry->refcnt);
 950                 copy_hash(cur_entry->hash, disk_entry->hash);
 951
 952                 if (reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
 953
 954                         /* PACKED_STREAMS entry  */
 955
 956                         if (!cur_subpacks) {
 957                                 /* Starting new run  */
 958                                 ret = load_subpack_info(wim, disk_entry,
 959                                                         num_entries - i,
 960                                                         &cur_subpacks,
 961                                                         &cur_num_subpacks);
 962                                 if (ret)
 963                                         goto out;
 964                         }
 965
 966                         if (reshdr.uncompressed_size == WIM_PACK_MAGIC_NUMBER) {
 967                                 /* Resource entry, not stream entry  */
 968                                 goto free_cur_entry_and_continue;
 969                         }
 970
 971                         /* Stream entry  */
 972
 973                         ret = bind_stream_to_subpack(&reshdr,
 974                                                      cur_entry,
 975                                                      cur_subpacks,
 976                                                      cur_num_subpacks);
 977                         if (ret)
 978                                 goto out;
 979
 980                 } else {
 981                         /* Normal stream/resource entry; PACKED_STREAMS not set.
 982                          */
 983
 984                         struct wim_resource_spec *rspec;
 985
 986                         if (unlikely(cur_subpacks)) {
 987                                 /* This entry terminated a packed run.  */
 988                                 ret = finish_subpacks(cur_subpacks,
 989                                                       cur_num_subpacks);
 990                                 cur_subpacks = NULL;
 991                                 if (ret)
 992                                         goto out;
 993                         }
 994
 995                         /* How to handle an uncompressed resource with its
 996                          * uncompressed size different from its compressed size?
 997                          *
 998                          * Based on a simple test, WIMGAPI seems to handle this
 999                          * as follows:
1000                          *
1001                          * if (size_in_wim > uncompressed_size) {
1002                          *      Ignore uncompressed_size; use size_in_wim
1003                          *      instead.
1004                          * } else {
1005                          *      Honor uncompressed_size, but treat the part of
1006                          *      the file data above size_in_wim as all zeros.
1007                          * }
1008                          *
1009                          * So we will do the same.  */
1010                         if (unlikely(!(reshdr.flags &
1011                                        WIM_RESHDR_FLAG_COMPRESSED) &&
1012                                      (reshdr.size_in_wim >
1013                                       reshdr.uncompressed_size)))
1014                         {
1015                                 reshdr.uncompressed_size = reshdr.size_in_wim;
1016                         }
1017
1018                         /* Set up a resource specification for this stream.  */
1019
1020                         rspec = MALLOC(sizeof(struct wim_resource_spec));
1021                         if (!rspec)
1022                                 goto oom;
1023
1024                         wim_res_hdr_to_spec(&reshdr, wim, rspec);
1025
1026                         cur_entry->offset_in_res = 0;
1027                         cur_entry->size = reshdr.uncompressed_size;
1028                         cur_entry->flags = reshdr.flags;
1029
1030                         lte_bind_wim_resource_spec(cur_entry, rspec);
1031                 }
1032
1033                 /* cur_entry is now a stream bound to a resource.  */
1034
1035                 /* Ignore entries with all zeroes in the hash field.  */
1036                 if (is_zero_hash(cur_entry->hash))
1037                         goto free_cur_entry_and_continue;
1038
1039                 /* Verify that the part number matches that of the underlying
1040                  * WIM file.  */
1041                 if (part_number != wim->hdr.part_number) {
1042                         num_wrong_part_entries++;
1043                         goto free_cur_entry_and_continue;
1044                 }
1045
1046                 if (reshdr.flags & WIM_RESHDR_FLAG_METADATA) {
1047
1048                         /* Lookup table entry for a metadata resource.  */
1049
1050                         /* Metadata entries with no references must be ignored.
1051                          * See, for example, the WinPE WIMs from the WAIK v2.1.
1052                          */
1053                         if (cur_entry->refcnt == 0)
1054                                 goto free_cur_entry_and_continue;
1055
1056                         if (cur_entry->refcnt != 1) {
1057                                 /* We don't currently support this case due to
1058                                  * the complications of multiple images sharing
1059                                  * the same metadata resource or a metadata
1060                                  * resource also being referenced by files.  */
1061                                 ERROR("Found metadata resource with refcnt != 1");
1062                                 ret = WIMLIB_ERR_INVALID_LOOKUP_TABLE_ENTRY;
1063                                 goto out;
1064                         }
1065
1066                         if (wim->hdr.part_number != 1) {
1067                                 WARNING("Ignoring metadata resource found in a "
1068                                         "non-first part of the split WIM");
1069                                 goto free_cur_entry_and_continue;
1070                         }
1071
1072                         /* The number of entries in the lookup table with
1073                          * WIM_RESHDR_FLAG_METADATA set should be the same as
1074                          * the image_count field in the WIM header.  */
1075                         if (image_index == wim->hdr.image_count) {
1076                                 WARNING("Found more metadata resources than images");
1077                                 goto free_cur_entry_and_continue;
1078                         }
1079
1080                         /* Notice very carefully:  We are assigning the metadata
1081                          * resources to images in the same order in which their
1082                          * lookup table entries occur on disk.  (This is also
1083                          * the behavior of Microsoft's software.)  In
1084                          * particular, this overrides the actual locations of
1085                          * the metadata resources themselves in the WIM file as
1086                          * well as any information written in the XML data.  */
1087                         DEBUG("Found metadata resource for image %"PRIu32" at "
1088                               "offset %"PRIu64".",
1089                               image_index + 1,
1090                               reshdr.offset_in_wim);
1091
1092                         wim->image_metadata[image_index++]->metadata_lte = cur_entry;
1093                 } else {
1094                         /* Lookup table entry for a non-metadata stream.  */
1095
1096                         /* Ignore this stream if it's a duplicate.  */
1097                         if (lookup_stream(table, cur_entry->hash)) {
1098                                 num_duplicate_entries++;
1099                                 goto free_cur_entry_and_continue;
1100                         }
1101
1102                         /* Insert the stream into the in-memory lookup table,
1103                          * keyed by its SHA1 message digest.  */
1104                         lookup_table_insert(table, cur_entry);
1105                 }
1106
1107                 continue;
1108
1109         free_cur_entry_and_continue:
1110                 if (cur_subpacks &&
1111                     cur_entry->resource_location == RESOURCE_IN_WIM)
1112                         lte_unbind_wim_resource_spec(cur_entry);
1113                 free_lookup_table_entry(cur_entry);
1114         }
1115         cur_entry = NULL;
1116
1117         if (cur_subpacks) {
1118                 /* End of lookup table terminated a packed run.  */
1119                 ret = finish_subpacks(cur_subpacks, cur_num_subpacks);
1120                 cur_subpacks = NULL;
1121                 if (ret)
1122                         goto out;
1123         }
1124
1125         if (wim->hdr.part_number == 1 && image_index != wim->hdr.image_count) {
1126                 WARNING("Could not find metadata resources for all images");
1127                 for (u32 i = image_index; i < wim->hdr.image_count; i++)
1128                         put_image_metadata(wim->image_metadata[i], NULL);
1129                 wim->hdr.image_count = image_index;
1130         }
1131
1132         if (num_duplicate_entries > 0) {
1133                 WARNING("Ignoring %zu duplicate streams in the WIM lookup table",
1134                         num_duplicate_entries);
1135         }
1136
1137         if (num_wrong_part_entries > 0) {
1138                 WARNING("Ignoring %zu streams with wrong part number",
1139                         num_wrong_part_entries);
1140         }
1141
1142         DEBUG("Done reading lookup table.");
1143         wim->lookup_table = table;
1144         ret = 0;
1145         goto out_free_buf;
1146
1147 oom:
1148         ERROR("Not enough memory to read lookup table!");
1149         ret = WIMLIB_ERR_NOMEM;
1150 out:
1151         free_subpack_info(cur_subpacks, cur_num_subpacks);
1152         free_lookup_table_entry(cur_entry);
1153         free_lookup_table(table);
1154 out_free_buf:
1155         FREE(buf);
1156         return ret;
1157 }
1158
1159 static void
1160 put_wim_lookup_table_entry(struct wim_lookup_table_entry_disk *disk_entry,
1161                            const struct wim_reshdr *out_reshdr,
1162                            u16 part_number, u32 refcnt, const u8 *hash)
1163 {
1164         put_wim_reshdr(out_reshdr, &disk_entry->reshdr);
1165         disk_entry->part_number = cpu_to_le16(part_number);
1166         disk_entry->refcnt = cpu_to_le32(refcnt);
1167         copy_hash(disk_entry->hash, hash);
1168 }
1169
1170 /* Note: the list of stream entries must be sorted so that all entries for the
1171  * same packed resource are consecutive.  In addition, entries with
1172  * WIM_RESHDR_FLAG_METADATA set must be in the same order as the indices of the
1173  * underlying images.  */
1174 int
1175 write_wim_lookup_table_from_stream_list(struct list_head *stream_list,
1176                                         struct filedes *out_fd,
1177                                         u16 part_number,
1178                                         struct wim_reshdr *out_reshdr,
1179                                         int write_resource_flags)
1180 {
1181         size_t table_size;
1182         struct wim_lookup_table_entry *lte;
1183         struct wim_lookup_table_entry_disk *table_buf;
1184         struct wim_lookup_table_entry_disk *table_buf_ptr;
1185         int ret;
1186         u64 prev_res_offset_in_wim = ~0ULL;
1187         u64 prev_uncompressed_size;
1188         u64 logical_offset;
1189
1190         table_size = 0;
1191         list_for_each_entry(lte, stream_list, lookup_table_list) {
1192                 table_size += sizeof(struct wim_lookup_table_entry_disk);
1193
1194                 if (lte->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS &&
1195                     lte->out_res_offset_in_wim != prev_res_offset_in_wim)
1196                 {
1197                         table_size += sizeof(struct wim_lookup_table_entry_disk);
1198                         prev_res_offset_in_wim = lte->out_res_offset_in_wim;
1199                 }
1200         }
1201
1202         DEBUG("Writing WIM lookup table (size=%zu, offset=%"PRIu64")",
1203               table_size, out_fd->offset);
1204
1205         table_buf = MALLOC(table_size);
1206         if (table_buf == NULL) {
1207                 ERROR("Failed to allocate %zu bytes for temporary lookup table",
1208                       table_size);
1209                 return WIMLIB_ERR_NOMEM;
1210         }
1211         table_buf_ptr = table_buf;
1212
1213         prev_res_offset_in_wim = ~0ULL;
1214         prev_uncompressed_size = 0;
1215         logical_offset = 0;
1216         list_for_each_entry(lte, stream_list, lookup_table_list) {
1217                 if (lte->out_reshdr.flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
1218                         struct wim_reshdr tmp_reshdr;
1219
1220                         /* Eww.  When WIMGAPI sees multiple resource packs, it
1221                          * expects the offsets to be adjusted as if there were
1222                          * really only one pack.  */
1223
1224                         if (lte->out_res_offset_in_wim != prev_res_offset_in_wim) {
1225                                 /* Put the resource entry for pack  */
1226                                 tmp_reshdr.offset_in_wim = lte->out_res_offset_in_wim;
1227                                 tmp_reshdr.size_in_wim = lte->out_res_size_in_wim;
1228                                 tmp_reshdr.uncompressed_size = WIM_PACK_MAGIC_NUMBER;
1229                                 tmp_reshdr.flags = WIM_RESHDR_FLAG_PACKED_STREAMS;
1230
1231                                 put_wim_lookup_table_entry(table_buf_ptr++,
1232                                                            &tmp_reshdr,
1233                                                            part_number,
1234                                                            1, zero_hash);
1235
1236                                 logical_offset += prev_uncompressed_size;
1237
1238                                 prev_res_offset_in_wim = lte->out_res_offset_in_wim;
1239                                 prev_uncompressed_size = lte->out_res_uncompressed_size;
1240                         }
1241                         tmp_reshdr = lte->out_reshdr;
1242                         tmp_reshdr.offset_in_wim += logical_offset;
1243                         put_wim_lookup_table_entry(table_buf_ptr++,
1244                                                    &tmp_reshdr,
1245                                                    part_number,
1246                                                    lte->out_refcnt,
1247                                                    lte->hash);
1248                 } else {
1249                         put_wim_lookup_table_entry(table_buf_ptr++,
1250                                                    &lte->out_reshdr,
1251                                                    part_number,
1252                                                    lte->out_refcnt,
1253                                                    lte->hash);
1254                 }
1255
1256         }
1257         wimlib_assert((u8*)table_buf_ptr - (u8*)table_buf == table_size);
1258
1259         /* Write the lookup table uncompressed.  Although wimlib can handle a
1260          * compressed lookup table, MS software cannot.  */
1261         ret = write_wim_resource_from_buffer(table_buf,
1262                                              table_size,
1263                                              WIM_RESHDR_FLAG_METADATA,
1264                                              out_fd,
1265                                              WIMLIB_COMPRESSION_TYPE_NONE,
1266                                              0,
1267                                              out_reshdr,
1268                                              NULL,
1269                                              write_resource_flags);
1270         FREE(table_buf);
1271         DEBUG("ret=%d", ret);
1272         return ret;
1273 }
1274
1275 /* Allocate a stream entry for the contents of the buffer, or re-use an existing
1276  * entry in @lookup_table for the same stream.  */
1277 struct wim_lookup_table_entry *
1278 new_stream_from_data_buffer(const void *buffer, size_t size,
1279                             struct wim_lookup_table *lookup_table)
1280 {
1281         u8 hash[SHA1_HASH_SIZE];
1282         struct wim_lookup_table_entry *lte, *existing_lte;
1283
1284         sha1_buffer(buffer, size, hash);
1285         existing_lte = lookup_stream(lookup_table, hash);
1286         if (existing_lte) {
1287                 wimlib_assert(existing_lte->size == size);
1288                 lte = existing_lte;
1289                 lte->refcnt++;
1290         } else {
1291                 void *buffer_copy;
1292                 lte = new_lookup_table_entry();
1293                 if (lte == NULL)
1294                         return NULL;
1295                 buffer_copy = memdup(buffer, size);
1296                 if (buffer_copy == NULL) {
1297                         free_lookup_table_entry(lte);
1298                         return NULL;
1299                 }
1300                 lte->resource_location  = RESOURCE_IN_ATTACHED_BUFFER;
1301                 lte->attached_buffer    = buffer_copy;
1302                 lte->size               = size;
1303                 copy_hash(lte->hash, hash);
1304                 lookup_table_insert(lookup_table, lte);
1305         }
1306         return lte;
1307 }
1308
1309 /* Calculate the SHA1 message digest of a stream and move it from the list of
1310  * unhashed streams to the stream lookup table, possibly joining it with an
1311  * existing lookup table entry for an identical stream.
1312  *
1313  * @lte:  An unhashed lookup table entry.
1314  * @lookup_table:  Lookup table for the WIM.
1315  * @lte_ret:  On success, write a pointer to the resulting lookup table
1316  *            entry to this location.  This will be the same as @lte
1317  *            if it was inserted into the lookup table, or different if
1318  *            a duplicate stream was found.
1319  *
1320  * Returns 0 on success; nonzero if there is an error reading the stream.
1321  */
1322 int
1323 hash_unhashed_stream(struct wim_lookup_table_entry *lte,
1324                      struct wim_lookup_table *lookup_table,
1325                      struct wim_lookup_table_entry **lte_ret)
1326 {
1327         int ret;
1328         struct wim_lookup_table_entry *duplicate_lte;
1329         struct wim_lookup_table_entry **back_ptr;
1330
1331         wimlib_assert(lte->unhashed);
1332
1333         /* back_ptr must be saved because @back_inode and @back_stream_id are in
1334          * union with the SHA1 message digest and will no longer be valid once
1335          * the SHA1 has been calculated. */
1336         back_ptr = retrieve_lte_pointer(lte);
1337
1338         ret = sha1_stream(lte);
1339         if (ret)
1340                 return ret;
1341
1342         /* Look for a duplicate stream */
1343         duplicate_lte = lookup_stream(lookup_table, lte->hash);
1344         list_del(&lte->unhashed_list);
1345         if (duplicate_lte) {
1346                 /* We have a duplicate stream.  Transfer the reference counts
1347                  * from this stream to the duplicate and update the reference to
1348                  * this stream (in an inode or ads_entry) to point to the
1349                  * duplicate.  The caller is responsible for freeing @lte if
1350                  * needed.  */
1351                 wimlib_assert(!(duplicate_lte->unhashed));
1352                 wimlib_assert(duplicate_lte->size == lte->size);
1353                 duplicate_lte->refcnt += lte->refcnt;
1354                 lte->refcnt = 0;
1355                 *back_ptr = duplicate_lte;
1356                 lte = duplicate_lte;
1357         } else {
1358                 /* No duplicate stream, so we need to insert this stream into
1359                  * the lookup table and treat it as a hashed stream. */
1360                 lookup_table_insert(lookup_table, lte);
1361                 lte->unhashed = 0;
1362         }
1363         *lte_ret = lte;
1364         return 0;
1365 }
1366
1367 void
1368 lte_to_wimlib_resource_entry(const struct wim_lookup_table_entry *lte,
1369                              struct wimlib_resource_entry *wentry)
1370 {
1371         memset(wentry, 0, sizeof(*wentry));
1372
1373         wentry->uncompressed_size = lte->size;
1374         if (lte->resource_location == RESOURCE_IN_WIM) {
1375                 wentry->part_number = lte->rspec->wim->hdr.part_number;
1376                 if (lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS) {
1377                         wentry->compressed_size = 0;
1378                         wentry->offset = lte->offset_in_res;
1379                 } else {
1380                         wentry->compressed_size = lte->rspec->size_in_wim;
1381                         wentry->offset = lte->rspec->offset_in_wim;
1382                 }
1383                 wentry->raw_resource_offset_in_wim = lte->rspec->offset_in_wim;
1384                 /*wentry->raw_resource_uncompressed_size = lte->rspec->uncompressed_size;*/
1385                 wentry->raw_resource_compressed_size = lte->rspec->size_in_wim;
1386         }
1387         copy_hash(wentry->sha1_hash, lte->hash);
1388         wentry->reference_count = lte->refcnt;
1389         wentry->is_compressed = (lte->flags & WIM_RESHDR_FLAG_COMPRESSED) != 0;
1390         wentry->is_metadata = (lte->flags & WIM_RESHDR_FLAG_METADATA) != 0;
1391         wentry->is_free = (lte->flags & WIM_RESHDR_FLAG_FREE) != 0;
1392         wentry->is_spanned = (lte->flags & WIM_RESHDR_FLAG_SPANNED) != 0;
1393         wentry->packed = (lte->flags & WIM_RESHDR_FLAG_PACKED_STREAMS) != 0;
1394 }
1395
1396 struct iterate_lte_context {
1397         wimlib_iterate_lookup_table_callback_t cb;
1398         void *user_ctx;
1399 };
1400
1401 static int
1402 do_iterate_lte(struct wim_lookup_table_entry *lte, void *_ctx)
1403 {
1404         struct iterate_lte_context *ctx = _ctx;
1405         struct wimlib_resource_entry entry;
1406
1407         lte_to_wimlib_resource_entry(lte, &entry);
1408         return (*ctx->cb)(&entry, ctx->user_ctx);
1409 }
1410
1411 /* API function documented in wimlib.h  */
1412 WIMLIBAPI int
1413 wimlib_iterate_lookup_table(WIMStruct *wim, int flags,
1414                             wimlib_iterate_lookup_table_callback_t cb,
1415                             void *user_ctx)
1416 {
1417         if (flags != 0)
1418                 return WIMLIB_ERR_INVALID_PARAM;
1419
1420         struct iterate_lte_context ctx = {
1421                 .cb = cb,
1422                 .user_ctx = user_ctx,
1423         };
1424         if (wim_has_metadata(wim)) {
1425                 int ret;
1426                 for (int i = 0; i < wim->hdr.image_count; i++) {
1427                         ret = do_iterate_lte(wim->image_metadata[i]->metadata_lte,
1428                                              &ctx);
1429                         if (ret)
1430                                 return ret;
1431                 }
1432         }
1433         return for_lookup_table_entry(wim->lookup_table, do_iterate_lte, &ctx);
1434 }