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