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   1 /*
   2  * dentry.c
   3  *
   4  * A dentry (directory entry) contains the metadata for a file.  In the WIM file
   5  * format, the dentries are stored in the "metadata resource" section right
   6  * after the security data.  Each image in the WIM file has its own metadata
   7  * resource with its own security data and dentry tree.  Dentries in different
   8  * images may share file resources by referring to the same lookup table
   9  * entries.
  10  */
  11
  12 /*
  13  *
  14  * Copyright (C) 2010 Carl Thijssen
  15  * Copyright (C) 2012 Eric Biggers
  16  *
  17  * This file is part of wimlib, a library for working with WIM files.
  18  *
  19  * wimlib is free software; you can redistribute it and/or modify it under the
  20  * terms of the GNU Lesser General Public License as published by the Free
  21  * Software Foundation; either version 2.1 of the License, or (at your option)
  22  * any later version.
  23  *
  24  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
  25  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
  26  * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
  27  * details.
  28  *
  29  * You should have received a copy of the GNU Lesser General Public License
  30  * along with wimlib; if not, see http://www.gnu.org/licenses/.
  31  */
  32
  33 #include "wimlib_internal.h"
  34 #include "dentry.h"
  35 #include "io.h"
  36 #include "timestamp.h"
  37 #include "lookup_table.h"
  38 #include "sha1.h"
  39 #include <errno.h>
  40 #include <unistd.h>
  41 #include <sys/stat.h>
  42
  43 /*
  44  * Returns true if @dentry has the UTF-8 file name @name that has length
  45  * @name_len.
  46  */
  47 static bool dentry_has_name(const struct dentry *dentry, const char *name,
  48                             size_t name_len)
  49 {
  50         if (dentry->file_name_utf8_len != name_len)
  51                 return false;
  52         return memcmp(dentry->file_name_utf8, name, name_len) == 0;
  53 }
  54
  55 /* Real length of a dentry, including the alternate data stream entries, which
  56  * are not included in the dentry->length field... */
  57 u64 dentry_total_length(const struct dentry *dentry)
  58 {
  59         u64 length = (dentry->length + 7) & ~7;
  60         for (u16 i = 0 ; i < dentry->num_ads; i++)
  61                 length += ads_entry_length(&dentry->ads_entries[i]);
  62         return length;
  63 }
  64
  65 /* Transfers file attributes from a `stat' buffer to a struct dentry. */
  66 void stbuf_to_dentry(const struct stat *stbuf, struct dentry *dentry)
  67 {
  68         if (S_ISLNK(stbuf->st_mode)) {
  69                 dentry->attributes = FILE_ATTRIBUTE_REPARSE_POINT;
  70                 dentry->reparse_tag = WIM_IO_REPARSE_TAG_SYMLINK;
  71         } else if (S_ISDIR(stbuf->st_mode)) {
  72                 dentry->attributes = FILE_ATTRIBUTE_DIRECTORY;
  73         } else {
  74                 dentry->attributes = FILE_ATTRIBUTE_NORMAL;
  75         }
  76         if (sizeof(ino_t) >= 8)
  77                 dentry->hard_link = (u64)stbuf->st_ino;
  78         else
  79                 dentry->hard_link = (u64)stbuf->st_ino |
  80                                    ((u64)stbuf->st_dev << (sizeof(ino_t) * 8));
  81 }
  82
  83
  84 /* Makes all timestamp fields for the dentry be the current time. */
  85 void dentry_update_all_timestamps(struct dentry *dentry)
  86 {
  87         u64 now = get_timestamp();
  88         dentry->creation_time    = now;
  89         dentry->last_access_time = now;
  90         dentry->last_write_time  = now;
  91 }
  92
  93 struct ads_entry *dentry_get_ads_entry(struct dentry *dentry,
  94                                        const char *stream_name)
  95 {
  96         size_t stream_name_len = strlen(stream_name);
  97         if (!stream_name)
  98                 return NULL;
  99         for (u16 i = 0; i < dentry->num_ads; i++)
 100                 if (ads_entry_has_name(&dentry->ads_entries[i],
 101                                        stream_name, stream_name_len))
 102                         return &dentry->ads_entries[i];
 103         return NULL;
 104 }
 105
 106 /* Add an alternate stream entry to a dentry and return a pointer to it, or NULL
 107  * on failure. */
 108 struct ads_entry *dentry_add_ads(struct dentry *dentry, const char *stream_name)
 109 {
 110         u16 num_ads = dentry->num_ads + 1;
 111         struct ads_entry *ads_entries;
 112         struct ads_entry *new_entry;
 113         if (num_ads == 0xffff)
 114                 return NULL;
 115         ads_entries = MALLOC(num_ads * sizeof(struct ads_entry));
 116         if (!ads_entries)
 117                 return NULL;
 118
 119         new_entry = &ads_entries[num_ads - 1];
 120         if (change_ads_name(new_entry, stream_name) != 0) {
 121                 FREE(ads_entries);
 122                 return NULL;
 123         }
 124
 125         memcpy(ads_entries, dentry->ads_entries,
 126                (num_ads - 1) * sizeof(struct ads_entry));
 127         FREE(dentry->ads_entries);
 128         dentry->ads_entries = ads_entries;
 129         dentry->num_ads = num_ads;
 130         return memset(new_entry, 0, sizeof(struct ads_entry));
 131 }
 132
 133 void dentry_remove_ads(struct dentry *dentry, struct ads_entry *ads_entry)
 134 {
 135         u16 idx = ads_entry - dentry->ads_entries;
 136         u16 following = dentry->num_ads - idx - 1;
 137
 138         destroy_ads_entry(ads_entry);
 139         memcpy(ads_entry, ads_entry + 1, following * sizeof(struct ads_entry));
 140
 141         /* We moved the ADS entries.  Adjust the stream lists. */
 142         for (u16 i = 0; i < following; i++) {
 143                 struct list_head *cur = &ads_entry[i].lte_group_list.list;
 144                 cur->prev->next = cur;
 145                 cur->next->prev = cur;
 146         }
 147
 148         dentry->num_ads--;
 149 }
 150
 151 /*
 152  * Calls a function on all directory entries in a directory tree.  It is called
 153  * on a parent before its children.
 154  */
 155 int for_dentry_in_tree(struct dentry *root,
 156                        int (*visitor)(struct dentry*, void*), void *arg)
 157 {
 158         int ret;
 159         struct dentry *child;
 160
 161         ret = visitor(root, arg);
 162
 163         if (ret != 0)
 164                 return ret;
 165
 166         child = root->children;
 167
 168         if (!child)
 169                 return 0;
 170
 171         do {
 172                 ret = for_dentry_in_tree(child, visitor, arg);
 173                 if (ret != 0)
 174                         return ret;
 175                 child = child->next;
 176         } while (child != root->children);
 177         return 0;
 178 }
 179
 180 /*
 181  * Like for_dentry_in_tree(), but the visitor function is always called on a
 182  * dentry's children before on itself.
 183  */
 184 int for_dentry_in_tree_depth(struct dentry *root,
 185                              int (*visitor)(struct dentry*, void*), void *arg)
 186 {
 187         int ret;
 188         struct dentry *child;
 189         struct dentry *next;
 190
 191         child = root->children;
 192         if (child) {
 193                 do {
 194                         next = child->next;
 195                         ret = for_dentry_in_tree_depth(child, visitor, arg);
 196                         if (ret != 0)
 197                                 return ret;
 198                         child = next;
 199                 } while (child != root->children);
 200         }
 201         return visitor(root, arg);
 202 }
 203
 204 /*
 205  * Calculate the full path of @dentry, based on its parent's full path and on
 206  * its UTF-8 file name.
 207  */
 208 int calculate_dentry_full_path(struct dentry *dentry, void *ignore)
 209 {
 210         char *full_path;
 211         u32 full_path_len;
 212         if (dentry_is_root(dentry)) {
 213                 full_path = MALLOC(2);
 214                 if (!full_path)
 215                         goto oom;
 216                 full_path[0] = '/';
 217                 full_path[1] = '\0';
 218                 full_path_len = 1;
 219         } else {
 220                 char *parent_full_path;
 221                 u32 parent_full_path_len;
 222                 const struct dentry *parent = dentry->parent;
 223
 224                 if (dentry_is_root(parent)) {
 225                         parent_full_path = "";
 226                         parent_full_path_len = 0;
 227                 } else {
 228                         parent_full_path = parent->full_path_utf8;
 229                         parent_full_path_len = parent->full_path_utf8_len;
 230                 }
 231
 232                 full_path_len = parent_full_path_len + 1 +
 233                                 dentry->file_name_utf8_len;
 234                 full_path = MALLOC(full_path_len + 1);
 235                 if (!full_path)
 236                         goto oom;
 237
 238                 memcpy(full_path, parent_full_path, parent_full_path_len);
 239                 full_path[parent_full_path_len] = '/';
 240                 memcpy(full_path + parent_full_path_len + 1,
 241                        dentry->file_name_utf8,
 242                        dentry->file_name_utf8_len);
 243                 full_path[full_path_len] = '\0';
 244         }
 245         FREE(dentry->full_path_utf8);
 246         dentry->full_path_utf8 = full_path;
 247         dentry->full_path_utf8_len = full_path_len;
 248         return 0;
 249 oom:
 250         ERROR("Out of memory while calculating dentry full path");
 251         return WIMLIB_ERR_NOMEM;
 252 }
 253
 254 /*
 255  * Recursively calculates the subdir offsets for a directory tree.
 256  *
 257  * @dentry:  The root of the directory tree.
 258  * @subdir_offset_p:  The current subdirectory offset; i.e., the subdirectory
 259  *      offset for @dentry.
 260  */
 261 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
 262 {
 263         struct dentry *child;
 264
 265         child = dentry->children;
 266         dentry->subdir_offset = *subdir_offset_p;
 267         if (child) {
 268
 269                 /* Advance the subdir offset by the amount of space the children
 270                  * of this dentry take up. */
 271                 do {
 272                         *subdir_offset_p += dentry_total_length(child);
 273                         child = child->next;
 274                 } while (child != dentry->children);
 275
 276                 /* End-of-directory dentry on disk. */
 277                 *subdir_offset_p += 8;
 278
 279                 /* Recursively call calculate_subdir_offsets() on all the
 280                  * children. */
 281                 do {
 282                         calculate_subdir_offsets(child, subdir_offset_p);
 283                         child = child->next;
 284                 } while (child != dentry->children);
 285         } else {
 286                 /* On disk, childless directories have a valid subdir_offset
 287                  * that points to an 8-byte end-of-directory dentry.  Regular
 288                  * files have a subdir_offset of 0. */
 289                 if (dentry_is_directory(dentry))
 290                         *subdir_offset_p += 8;
 291                 else
 292                         dentry->subdir_offset = 0;
 293         }
 294 }
 295
 296
 297 /* Returns the child of @dentry that has the file name @name.
 298  * Returns NULL if no child has the name. */
 299 struct dentry *get_dentry_child_with_name(const struct dentry *dentry,
 300                                                         const char *name)
 301 {
 302         struct dentry *child;
 303         size_t name_len;
 304
 305         child = dentry->children;
 306         if (child) {
 307                 name_len = strlen(name);
 308                 do {
 309                         if (dentry_has_name(child, name, name_len))
 310                                 return child;
 311                         child = child->next;
 312                 } while (child != dentry->children);
 313         }
 314         return NULL;
 315 }
 316
 317 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
 318  * @cur_dir.  Returns NULL if no dentry having the path is found. */
 319 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir, const char *path)
 320 {
 321         struct dentry *child;
 322         size_t base_len;
 323         const char *new_path;
 324
 325         if (*path == '\0')
 326                 return cur_dir;
 327
 328         child = cur_dir->children;
 329         if (child) {
 330                 new_path = path_next_part(path, &base_len);
 331                 do {
 332                         if (dentry_has_name(child, path, base_len))
 333                                 return get_dentry_relative_path(child, new_path);
 334                         child = child->next;
 335                 } while (child != cur_dir->children);
 336         }
 337         return NULL;
 338 }
 339
 340 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
 341  * such dentry. */
 342 struct dentry *get_dentry(WIMStruct *w, const char *path)
 343 {
 344         struct dentry *root = wim_root_dentry(w);
 345         while (*path == '/')
 346                 path++;
 347         return get_dentry_relative_path(root, path);
 348 }
 349
 350 /* Returns the parent directory for the @path. */
 351 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
 352 {
 353         size_t path_len = strlen(path);
 354         char buf[path_len + 1];
 355
 356         memcpy(buf, path, path_len + 1);
 357
 358         to_parent_name(buf, path_len);
 359
 360         return get_dentry(w, buf);
 361 }
 362
 363 /* Prints the full path of a dentry. */
 364 int print_dentry_full_path(struct dentry *dentry, void *ignore)
 365 {
 366         if (dentry->full_path_utf8)
 367                 puts(dentry->full_path_utf8);
 368         return 0;
 369 }
 370
 371 struct file_attr_flag {
 372         u32 flag;
 373         const char *name;
 374 };
 375 struct file_attr_flag file_attr_flags[] = {
 376         {FILE_ATTRIBUTE_READONLY,               "READONLY"},
 377         {FILE_ATTRIBUTE_HIDDEN,         "HIDDEN"},
 378         {FILE_ATTRIBUTE_SYSTEM,         "SYSTEM"},
 379         {FILE_ATTRIBUTE_DIRECTORY,              "DIRECTORY"},
 380         {FILE_ATTRIBUTE_ARCHIVE,                "ARCHIVE"},
 381         {FILE_ATTRIBUTE_DEVICE,         "DEVICE"},
 382         {FILE_ATTRIBUTE_NORMAL,         "NORMAL"},
 383         {FILE_ATTRIBUTE_TEMPORARY,              "TEMPORARY"},
 384         {FILE_ATTRIBUTE_SPARSE_FILE,    "SPARSE_FILE"},
 385         {FILE_ATTRIBUTE_REPARSE_POINT,  "REPARSE_POINT"},
 386         {FILE_ATTRIBUTE_COMPRESSED,             "COMPRESSED"},
 387         {FILE_ATTRIBUTE_OFFLINE,                "OFFLINE"},
 388         {FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,"NOT_CONTENT_INDEXED"},
 389         {FILE_ATTRIBUTE_ENCRYPTED,              "ENCRYPTED"},
 390         {FILE_ATTRIBUTE_VIRTUAL,                "VIRTUAL"},
 391 };
 392
 393 /* Prints a directory entry.  @lookup_table is a pointer to the lookup table, or
 394  * NULL if the resource entry for the dentry is not to be printed. */
 395 int print_dentry(struct dentry *dentry, void *lookup_table)
 396 {
 397         struct lookup_table_entry *lte;
 398         unsigned i;
 399
 400         printf("[DENTRY]\n");
 401         printf("Length            = %"PRIu64"\n", dentry->length);
 402         printf("Attributes        = 0x%x\n", dentry->attributes);
 403         for (i = 0; i < ARRAY_LEN(file_attr_flags); i++)
 404                 if (file_attr_flags[i].flag & dentry->attributes)
 405                         printf("    FILE_ATTRIBUTE_%s is set\n",
 406                                 file_attr_flags[i].name);
 407         printf("Security ID       = %d\n", dentry->security_id);
 408         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
 409         /*printf("Unused1           = 0x%"PRIu64"\n", dentry->unused1);*/
 410         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
 411         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
 412         printf("Last Access Time  = 0x%"PRIx64"\n", dentry->last_access_time);
 413         printf("Last Write Time   = 0x%"PRIx64"\n", dentry->last_write_time);
 414         printf("Hash              = 0x");
 415         print_hash(dentry->hash);
 416         putchar('\n');
 417         printf("Reparse Tag       = 0x%"PRIx32"\n", dentry->reparse_tag);
 418         printf("Hard Link Group   = 0x%"PRIx64"\n", dentry->hard_link);
 419         printf("Number of Alternate Data Streams = %hu\n", dentry->num_ads);
 420         printf("Filename          = \"");
 421         print_string(dentry->file_name, dentry->file_name_len);
 422         puts("\"");
 423         printf("Filename Length   = %hu\n", dentry->file_name_len);
 424         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
 425         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
 426         printf("Short Name        = \"");
 427         print_string(dentry->short_name, dentry->short_name_len);
 428         puts("\"");
 429         printf("Short Name Length = %hu\n", dentry->short_name_len);
 430         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
 431         if (lookup_table && (lte = __lookup_resource(lookup_table, dentry->hash)))
 432                 print_lookup_table_entry(lte, NULL);
 433         else
 434                 putchar('\n');
 435         for (u16 i = 0; i < dentry->num_ads; i++) {
 436                 printf("[Alternate Stream Entry %u]\n", i);
 437                 printf("Name = \"%s\"\n", dentry->ads_entries[i].stream_name_utf8);
 438                 printf("Name Length (UTF-16) = %u\n",
 439                                 dentry->ads_entries[i].stream_name_len);
 440                 printf("Hash              = 0x");
 441                 print_hash(dentry->ads_entries[i].hash);
 442                 if (lookup_table &&
 443                      (lte = __lookup_resource(lookup_table,
 444                                               dentry->ads_entries[i].hash)))
 445                 {
 446                         print_lookup_table_entry(lte, NULL);
 447                 } else {
 448                         putchar('\n');
 449                 }
 450         }
 451         return 0;
 452 }
 453
 454 static inline void dentry_common_init(struct dentry *dentry)
 455 {
 456         memset(dentry, 0, sizeof(struct dentry));
 457         dentry->refcnt = 1;
 458         dentry->security_id = -1;
 459         dentry->link_group_master_status = GROUP_SLAVE;
 460 }
 461
 462 /*
 463  * Creates an unlinked directory entry.
 464  *
 465  * @name:    The base name of the new dentry.
 466  * @return:  A pointer to the new dentry, or NULL if out of memory.
 467  */
 468 struct dentry *new_dentry(const char *name)
 469 {
 470         struct dentry *dentry;
 471
 472         dentry = MALLOC(sizeof(struct dentry));
 473         if (!dentry)
 474                 goto err;
 475
 476         dentry_common_init(dentry);
 477         if (change_dentry_name(dentry, name) != 0)
 478                 goto err;
 479
 480         dentry_update_all_timestamps(dentry);
 481         dentry->next   = dentry;
 482         dentry->prev   = dentry;
 483         dentry->parent = dentry;
 484         INIT_LIST_HEAD(&dentry->link_group_list);
 485         return dentry;
 486 err:
 487         FREE(dentry);
 488         ERROR("Failed to allocate new dentry");
 489         return NULL;
 490 }
 491
 492 void dentry_free_ads_entries(struct dentry *dentry)
 493 {
 494         for (u16 i = 0; i < dentry->num_ads; i++)
 495                 destroy_ads_entry(&dentry->ads_entries[i]);
 496         FREE(dentry->ads_entries);
 497         dentry->ads_entries = NULL;
 498         dentry->num_ads = 0;
 499 }
 500
 501 static void __destroy_dentry(struct dentry *dentry)
 502 {
 503         FREE(dentry->file_name);
 504         FREE(dentry->file_name_utf8);
 505         FREE(dentry->short_name);
 506         FREE(dentry->full_path_utf8);
 507         FREE(dentry->extracted_file);
 508 }
 509
 510 void free_dentry(struct dentry *dentry)
 511 {
 512         __destroy_dentry(dentry);
 513         if (dentry->link_group_master_status != GROUP_SLAVE)
 514                 dentry_free_ads_entries(dentry);
 515         FREE(dentry);
 516 }
 517
 518 void put_dentry(struct dentry *dentry)
 519 {
 520         if (dentry->link_group_master_status == GROUP_MASTER) {
 521                 struct dentry *new_master;
 522                 list_for_each_entry(new_master, &dentry->link_group_list,
 523                                     link_group_list)
 524                 {
 525                         if (new_master->link_group_master_status == GROUP_SLAVE) {
 526                                 new_master->link_group_master_status = GROUP_MASTER;
 527                                 dentry->link_group_master_status = GROUP_SLAVE;
 528                                 break;
 529                         }
 530                 }
 531         }
 532         struct list_head *next;
 533         next = dentry->link_group_list.next;
 534         list_del(&dentry->link_group_list);
 535         /*if (next->next == next)*/
 536                 /*container_of(next, struct dentry, link_group_list)->hard_link = 0;*/
 537         free_dentry(dentry);
 538 }
 539
 540 static bool dentries_have_same_ads(const struct dentry *d1,
 541                                    const struct dentry *d2)
 542 {
 543         /* Verify stream names and hashes are the same */
 544         for (u16 i = 0; i < d1->num_ads; i++) {
 545                 if (strcmp(d1->ads_entries[i].stream_name_utf8,
 546                            d2->ads_entries[i].stream_name_utf8) != 0)
 547                         return false;
 548                 if (memcmp(d1->ads_entries[i].hash,
 549                            d2->ads_entries[i].hash,
 550                            WIM_HASH_SIZE) != 0)
 551                         return false;
 552         }
 553         return true;
 554 }
 555
 556 /* Share the alternate stream entries between hard-linked dentries. */
 557 int share_dentry_ads(struct dentry *master, struct dentry *slave)
 558 {
 559         const char *mismatch_type;
 560         wimlib_assert(master->num_ads == 0 ||
 561                       master->ads_entries != slave->ads_entries);
 562         if (master->attributes != slave->attributes) {
 563                 mismatch_type = "attributes";
 564                 goto mismatch;
 565         }
 566         if (master->attributes & FILE_ATTRIBUTE_DIRECTORY) {
 567                 WARNING("`%s' is hard-linked to `%s', which is a directory ",
 568                         slave->full_path_utf8, master->full_path_utf8);
 569                 return WIMLIB_ERR_INVALID_DENTRY;
 570         }
 571         if (master->security_id != slave->security_id) {
 572                 mismatch_type = "security ID";
 573                 goto mismatch;
 574         }
 575         if (memcmp(master->hash, slave->hash, WIM_HASH_SIZE) != 0) {
 576                 mismatch_type = "main file resource";
 577                 goto mismatch;
 578         }
 579         if (!dentries_have_same_ads(master, slave)) {
 580                 mismatch_type = "Alternate Stream Entries";
 581                 goto mismatch;
 582         }
 583         dentry_free_ads_entries(slave);
 584         slave->ads_entries = master->ads_entries;
 585         slave->link_group_master_status = GROUP_SLAVE;
 586         return 0;
 587 mismatch:
 588         WARNING("Dentries `%s' and `%s' in the same hard-link group but "
 589                 "do not share the same %s",
 590                 master->full_path_utf8, slave->full_path_utf8,
 591                 mismatch_type);
 592         return WIMLIB_ERR_INVALID_DENTRY;
 593 }
 594
 595 /* clones a dentry.
 596  *
 597  * Beware:
 598  *      - memory for file names is not cloned
 599  *      - next, prev, and children pointers and not touched
 600  *      - stream entries are not cloned.
 601  */
 602 struct dentry *clone_dentry(struct dentry *old)
 603 {
 604         struct dentry *new = MALLOC(sizeof(struct dentry));
 605         if (!new)
 606                 return NULL;
 607         memcpy(new, old, sizeof(struct dentry));
 608         new->file_name          = NULL;
 609         new->file_name_len      = 0;
 610         new->file_name_utf8     = NULL;
 611         new->file_name_utf8_len = 0;
 612         new->short_name         = NULL;
 613         new->short_name_len     = 0;
 614         return new;
 615 }
 616
 617 /* Arguments for do_free_dentry(). */
 618 struct free_dentry_args {
 619         struct lookup_table *lookup_table;
 620         bool lt_decrement_refcnt;
 621 };
 622
 623 /*
 624  * This function is passed as an argument to for_dentry_in_tree_depth() in order
 625  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
 626  */
 627 static int do_free_dentry(struct dentry *dentry, void *__args)
 628 {
 629         struct free_dentry_args *args = (struct free_dentry_args*)__args;
 630
 631         if (args->lt_decrement_refcnt && !dentry_is_directory(dentry)) {
 632                 lookup_table_decrement_refcnt(args->lookup_table,
 633                                               dentry->hash);
 634         }
 635
 636         wimlib_assert(dentry->refcnt >= 1);
 637         if (--dentry->refcnt == 0)
 638                 free_dentry(dentry);
 639         return 0;
 640 }
 641
 642 /*
 643  * Unlinks and frees a dentry tree.
 644  *
 645  * @root:               The root of the tree.
 646  * @lookup_table:       The lookup table for dentries.
 647  * @decrement_refcnt:   True if the dentries in the tree are to have their
 648  *                      reference counts in the lookup table decremented.
 649  */
 650 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table,
 651                       bool lt_decrement_refcnt)
 652 {
 653         if (!root || !root->parent)
 654                 return;
 655
 656         struct free_dentry_args args;
 657         args.lookup_table        = lookup_table;
 658         args.lt_decrement_refcnt = lt_decrement_refcnt;
 659         for_dentry_in_tree_depth(root, do_free_dentry, &args);
 660 }
 661
 662 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
 663 {
 664         dentry->refcnt++;
 665         return 0;
 666 }
 667
 668 /*
 669  * Links a dentry into the directory tree.
 670  *
 671  * @dentry: The dentry to link.
 672  * @parent: The dentry that will be the parent of @dentry.
 673  */
 674 void link_dentry(struct dentry *dentry, struct dentry *parent)
 675 {
 676         dentry->parent = parent;
 677         if (parent->children) {
 678                 /* Not an only child; link to siblings. */
 679                 dentry->next = parent->children;
 680                 dentry->prev = parent->children->prev;
 681                 dentry->next->prev = dentry;
 682                 dentry->prev->next = dentry;
 683         } else {
 684                 /* Only child; link to parent. */
 685                 parent->children = dentry;
 686                 dentry->next = dentry;
 687                 dentry->prev = dentry;
 688         }
 689 }
 690
 691
 692 /* Unlink a dentry from the directory tree.
 693  *
 694  * Note: This merely removes it from the in-memory tree structure.  See
 695  * remove_dentry() in mount.c for a function implemented on top of this one that
 696  * frees the dentry and implements reference counting for the lookup table
 697  * entries. */
 698 void unlink_dentry(struct dentry *dentry)
 699 {
 700         if (dentry_is_root(dentry))
 701                 return;
 702         if (dentry_is_only_child(dentry)) {
 703                 dentry->parent->children = NULL;
 704         } else {
 705                 if (dentry_is_first_sibling(dentry))
 706                         dentry->parent->children = dentry->next;
 707                 dentry->next->prev = dentry->prev;
 708                 dentry->prev->next = dentry->next;
 709         }
 710 }
 711
 712
 713 /* Recalculates the length of @dentry based on its file name length and short
 714  * name length.  */
 715 static inline void recalculate_dentry_size(struct dentry *dentry)
 716 {
 717         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len +
 718                          2 + dentry->short_name_len;
 719         /* Must be multiple of 8. */
 720         dentry->length = (dentry->length + 7) & ~7;
 721 }
 722
 723 int get_names(char **name_utf16_ret, char **name_utf8_ret,
 724               u16 *name_utf16_len_ret, u16 *name_utf8_len_ret,
 725               const char *name)
 726 {
 727         size_t utf8_len;
 728         size_t utf16_len;
 729         char *name_utf16, *name_utf8;
 730
 731         utf8_len = strlen(name);
 732
 733         name_utf16 = utf8_to_utf16(name, utf8_len, &utf16_len);
 734
 735         if (!name_utf16)
 736                 return WIMLIB_ERR_NOMEM;
 737
 738         name_utf8 = MALLOC(utf8_len + 1);
 739         if (!name_utf8) {
 740                 FREE(name_utf8);
 741                 return WIMLIB_ERR_NOMEM;
 742         }
 743         memcpy(name_utf8, name, utf8_len + 1);
 744         FREE(*name_utf8_ret);
 745         FREE(*name_utf16_ret);
 746         *name_utf8_ret      = name_utf8;
 747         *name_utf16_ret     = name_utf16;
 748         *name_utf8_len_ret  = utf8_len;
 749         *name_utf16_len_ret = utf16_len;
 750         return 0;
 751 }
 752
 753 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
 754  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
 755  * full_path_utf8 fields.  Also recalculates its length. */
 756 int change_dentry_name(struct dentry *dentry, const char *new_name)
 757 {
 758         int ret;
 759
 760         ret = get_names(&dentry->file_name, &dentry->file_name_utf8,
 761                         &dentry->file_name_len, &dentry->file_name_utf8_len,
 762                          new_name);
 763         if (ret == 0)
 764                 recalculate_dentry_size(dentry);
 765         return ret;
 766 }
 767
 768 int change_ads_name(struct ads_entry *entry, const char *new_name)
 769 {
 770         return get_names(&entry->stream_name, &entry->stream_name_utf8,
 771                          &entry->stream_name_len,
 772                          &entry->stream_name_utf8_len,
 773                           new_name);
 774 }
 775
 776 /* Parameters for calculate_dentry_statistics(). */
 777 struct image_statistics {
 778         struct lookup_table *lookup_table;
 779         u64 *dir_count;
 780         u64 *file_count;
 781         u64 *total_bytes;
 782         u64 *hard_link_bytes;
 783 };
 784
 785 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
 786 {
 787         struct image_statistics *stats;
 788         struct lookup_table_entry *lte;
 789         u16 i;
 790
 791         stats = arg;
 792
 793         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
 794                 ++*stats->dir_count;
 795         else
 796                 ++*stats->file_count;
 797
 798         lte = __lookup_resource(stats->lookup_table, dentry->hash);
 799         i = 0;
 800         while (1) {
 801                 if (lte) {
 802                         u64 size = lte->resource_entry.original_size;
 803                         *stats->total_bytes += size;
 804                         if (++lte->out_refcnt == 1)
 805                                 *stats->hard_link_bytes += size;
 806                 }
 807                 if (i == dentry->num_ads)
 808                         break;
 809                 lte = __lookup_resource(stats->lookup_table,
 810                                         dentry->ads_entries[i].hash);
 811                 i++;
 812         }
 813
 814         return 0;
 815 }
 816
 817 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
 818                                    u64 *dir_count_ret, u64 *file_count_ret,
 819                                    u64 *total_bytes_ret,
 820                                    u64 *hard_link_bytes_ret)
 821 {
 822         struct image_statistics stats;
 823         *dir_count_ret         = 0;
 824         *file_count_ret        = 0;
 825         *total_bytes_ret       = 0;
 826         *hard_link_bytes_ret   = 0;
 827         stats.lookup_table     = table;
 828         stats.dir_count       = dir_count_ret;
 829         stats.file_count      = file_count_ret;
 830         stats.total_bytes     = total_bytes_ret;
 831         stats.hard_link_bytes = hard_link_bytes_ret;
 832         for_lookup_table_entry(table, zero_out_refcnts, NULL);
 833         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
 834 }
 835
 836 static int read_ads_entries(const u8 *p, struct dentry *dentry,
 837                             u64 remaining_size)
 838 {
 839         u16 num_ads = dentry->num_ads;
 840         struct ads_entry *ads_entries = CALLOC(num_ads, sizeof(struct ads_entry));
 841         int ret;
 842         if (!ads_entries) {
 843                 ERROR("Could not allocate memory for %"PRIu16" "
 844                       "alternate data stream entries", num_ads);
 845                 return WIMLIB_ERR_NOMEM;
 846         }
 847         DEBUG2("Reading %"PRIu16" alternate data streams "
 848                "(remaining size = %"PRIu64")", num_ads, remaining_size);
 849
 850         for (u16 i = 0; i < num_ads; i++) {
 851                 struct ads_entry *cur_entry = &ads_entries[i];
 852                 u64 length;
 853                 size_t utf8_len;
 854                 const char *p_save = p;
 855                 /* Read the base stream entry, excluding the stream name. */
 856                 if (remaining_size < WIM_ADS_ENTRY_DISK_SIZE) {
 857                         ERROR("Stream entries go past end of metadata resource");
 858                         ERROR("(remaining_size = %"PRIu64")", remaining_size);
 859                         ret = WIMLIB_ERR_INVALID_DENTRY;
 860                         goto out_free_ads_entries;
 861                 }
 862                 remaining_size -= WIM_ADS_ENTRY_DISK_SIZE;
 863
 864                 p = get_u64(p, &length); /* ADS entry length */
 865
 866                 DEBUG2("ADS length = %"PRIu64, length);
 867
 868                 p += 8; /* Unused */
 869                 p = get_bytes(p, WIM_HASH_SIZE, (u8*)cur_entry->hash);
 870                 p = get_u16(p, &cur_entry->stream_name_len);
 871
 872                 DEBUG2("Stream name length = %u", cur_entry->stream_name_len);
 873
 874                 cur_entry->stream_name = NULL;
 875                 cur_entry->stream_name_utf8 = NULL;
 876
 877                 if (remaining_size < cur_entry->stream_name_len + 2) {
 878                         ERROR("Stream entries go past end of metadata resource");
 879                         ERROR("(remaining_size = %"PRIu64" bytes, stream_name_len "
 880                               "= %"PRIu16" bytes", remaining_size,
 881                               cur_entry->stream_name_len);
 882                         ret = WIMLIB_ERR_INVALID_DENTRY;
 883                         goto out_free_ads_entries;
 884                 }
 885                 remaining_size -= cur_entry->stream_name_len + 2;
 886
 887                 cur_entry->stream_name = MALLOC(cur_entry->stream_name_len);
 888                 if (!cur_entry->stream_name) {
 889                         ret = WIMLIB_ERR_NOMEM;
 890                         goto out_free_ads_entries;
 891                 }
 892                 get_bytes(p, cur_entry->stream_name_len,
 893                           (u8*)cur_entry->stream_name);
 894                 cur_entry->stream_name_utf8 = utf16_to_utf8(cur_entry->stream_name,
 895                                                             cur_entry->stream_name_len,
 896                                                             &utf8_len);
 897                 cur_entry->stream_name_utf8_len = utf8_len;
 898
 899                 if (!cur_entry->stream_name_utf8) {
 900                         ret = WIMLIB_ERR_NOMEM;
 901                         goto out_free_ads_entries;
 902                 }
 903                 p = p_save + ads_entry_length(cur_entry);
 904         }
 905         dentry->ads_entries = ads_entries;
 906         return 0;
 907 out_free_ads_entries:
 908         for (u16 i = 0; i < num_ads; i++) {
 909                 FREE(ads_entries[i].stream_name);
 910                 FREE(ads_entries[i].stream_name_utf8);
 911         }
 912         FREE(ads_entries);
 913         return ret;
 914 }
 915
 916 /*
 917  * Reads a directory entry from the metadata resource.
 918  */
 919 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
 920                 u64 offset, struct dentry *dentry)
 921 {
 922         const u8 *p;
 923         u64 calculated_size;
 924         char *file_name;
 925         char *file_name_utf8;
 926         char *short_name;
 927         u16 short_name_len;
 928         u16 file_name_len;
 929         size_t file_name_utf8_len;
 930         int ret;
 931
 932         dentry_common_init(dentry);
 933
 934         /*Make sure the dentry really fits into the metadata resource.*/
 935         if (offset + 8 > metadata_resource_len) {
 936                 ERROR("Directory entry starting at %"PRIu64" ends past the "
 937                       "end of the metadata resource (size %"PRIu64")",
 938                       offset, metadata_resource_len);
 939                 return WIMLIB_ERR_INVALID_DENTRY;
 940         }
 941
 942         /* Before reading the whole entry, we need to read just the length.
 943          * This is because an entry of length 8 (that is, just the length field)
 944          * terminates the list of sibling directory entries. */
 945
 946         p = get_u64(&metadata_resource[offset], &dentry->length);
 947
 948         /* A zero length field (really a length of 8, since that's how big the
 949          * directory entry is...) indicates that this is the end of directory
 950          * dentry.  We do not read it into memory as an actual dentry, so just
 951          * return true in that case. */
 952         if (dentry->length == 0)
 953                 return 0;
 954
 955         if (offset + dentry->length >= metadata_resource_len) {
 956                 ERROR("Directory entry at offset %"PRIu64" and with size "
 957                       "%"PRIu64" ends past the end of the metadata resource "
 958                       "(size %"PRIu64")",
 959                       offset, dentry->length, metadata_resource_len);
 960                 return WIMLIB_ERR_INVALID_DENTRY;
 961         }
 962
 963         /* If it is a recognized length, read the rest of the directory entry.
 964          * Note: The root directory entry has no name, and its length does not
 965          * include the short name length field.  */
 966         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
 967                 ERROR("Directory entry has invalid length of %"PRIu64" bytes",
 968                       dentry->length);
 969                 return WIMLIB_ERR_INVALID_DENTRY;
 970         }
 971
 972         p = get_u32(p, &dentry->attributes);
 973         p = get_u32(p, (u32*)&dentry->security_id);
 974         p = get_u64(p, &dentry->subdir_offset);
 975
 976         /* 2 unused fields */
 977         p += 2 * sizeof(u64);
 978         /*p = get_u64(p, &dentry->unused1);*/
 979         /*p = get_u64(p, &dentry->unused2);*/
 980
 981         p = get_u64(p, &dentry->creation_time);
 982         p = get_u64(p, &dentry->last_access_time);
 983         p = get_u64(p, &dentry->last_write_time);
 984
 985         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
 986
 987         /*
 988          * I don't know what's going on here.  It seems like M$ screwed up the
 989          * reparse points, then put the fields in the same place and didn't
 990          * document it.  The WIM_HDR_FLAG_RP_FIX flag in the WIM header might
 991          * have something to do with this, but it's not documented.
 992          */
 993         if (dentry->attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
 994                 /* ??? */
 995                 p += 4;
 996                 p = get_u32(p, &dentry->reparse_tag);
 997                 p += 4;
 998         } else {
 999                 p = get_u32(p, &dentry->reparse_tag);
1000                 p = get_u64(p, &dentry->hard_link);
1001         }
1002
1003         /* By the way, the reparse_reserved field does not actually exist (at
1004          * least when the file is not a reparse point) */
1005
1006
1007         p = get_u16(p, &dentry->num_ads);
1008
1009         p = get_u16(p, &short_name_len);
1010         p = get_u16(p, &file_name_len);
1011
1012         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
1013                           short_name_len;
1014
1015         if (dentry->length < calculated_size) {
1016                 ERROR("Unexpected end of directory entry! (Expected "
1017                       "%"PRIu64" bytes, got %"PRIu64" bytes. "
1018                       "short_name_len = %hu, file_name_len = %hu)",
1019                       calculated_size, dentry->length,
1020                       short_name_len, file_name_len);
1021                 return WIMLIB_ERR_INVALID_DENTRY;
1022         }
1023
1024         /* Read the filename. */
1025         file_name = MALLOC(file_name_len);
1026         if (!file_name) {
1027                 ERROR("Failed to allocate %hu bytes for dentry file name",
1028                       file_name_len);
1029                 return WIMLIB_ERR_NOMEM;
1030         }
1031         p = get_bytes(p, file_name_len, file_name);
1032
1033         /* Convert filename to UTF-8. */
1034         file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
1035                                        &file_name_utf8_len);
1036
1037         if (!file_name_utf8) {
1038                 ERROR("Failed to allocate memory to convert UTF-16 "
1039                       "filename (%hu bytes) to UTF-8", file_name_len);
1040                 ret = WIMLIB_ERR_NOMEM;
1041                 goto out_free_file_name;
1042         }
1043
1044         /* Undocumented padding between file name and short name.  This probably
1045          * is supposed to be a terminating null character. */
1046         p += 2;
1047
1048         /* Read the short filename. */
1049         short_name = MALLOC(short_name_len);
1050         if (!short_name) {
1051                 ERROR("Failed to allocate %hu bytes for short filename",
1052                       short_name_len);
1053                 ret = WIMLIB_ERR_NOMEM;
1054                 goto out_free_file_name_utf8;
1055         }
1056
1057         p = get_bytes(p, short_name_len, short_name);
1058
1059         /* Some directory entries inexplicibly have a little over 70 bytes of
1060          * extra data.  The exact amount of data seems to be 72 bytes, but it is
1061          * aligned on the next 8-byte boundary.  Here's an example of the
1062          * aligned data:
1063          *
1064          * 01000000400000006c786bbac58ede11b0bb00261870892ab6adb76fe63a3
1065          * e468fca86530d2effa16c786bbac58ede11b0bb00261870892a0000000000
1066          * 0000000000000000000000
1067          *
1068          * Here's one interpretation of how the data is laid out.
1069          *
1070          * struct unknown {
1071          *      u32 field1; (always 0x00000001)
1072          *      u32 field2; (always 0x40000000)
1073          *      u16 field3;
1074          *      u32 field4;
1075          *      u32 field5;
1076          *      u32 field6;
1077          *      u8  data[48]; (???)
1078          *      u64 reserved1; (always 0)
1079          *      u64 reserved2; (always 0)
1080          * };*/
1081 #if 0
1082         if (dentry->length - calculated_size >= WIM_ADS_ENTRY_DISK_SIZE) {
1083                 printf("%s: %lu / %lu (", file_name_utf8,
1084                                 calculated_size, dentry->length);
1085                 print_string(p + WIM_ADS_ENTRY_DISK_SIZE, dentry->length - calculated_size - WIM_ADS_ENTRY_DISK_SIZE);
1086                 puts(")");
1087                 print_byte_field(p, dentry->length - calculated_size);
1088                 putchar('\n');
1089         }
1090 #endif
1091
1092         if (dentry->num_ads != 0) {
1093                 calculated_size = (calculated_size + 7) & ~7;
1094                 if (calculated_size > metadata_resource_len - offset) {
1095                         ERROR("Not enough space in metadata resource for "
1096                               "alternate stream entries");
1097                         ret = WIMLIB_ERR_INVALID_DENTRY;
1098                         goto out_free_short_name;
1099                 }
1100                 ret = read_ads_entries(&metadata_resource[offset + calculated_size],
1101                                        dentry,
1102                                        metadata_resource_len - offset - calculated_size);
1103                 if (ret != 0)
1104                         goto out_free_short_name;
1105         }
1106
1107         dentry->file_name          = file_name;
1108         dentry->file_name_utf8     = file_name_utf8;
1109         dentry->short_name         = short_name;
1110         dentry->file_name_len      = file_name_len;
1111         dentry->file_name_utf8_len = file_name_utf8_len;
1112         dentry->short_name_len     = short_name_len;
1113         return 0;
1114 out_free_short_name:
1115         FREE(short_name);
1116 out_free_file_name_utf8:
1117         FREE(file_name_utf8);
1118 out_free_file_name:
1119         FREE(file_name);
1120         return ret;
1121 }
1122
1123 /*
1124  * Writes a dentry to an output buffer.
1125  *
1126  * @dentry:  The dentry structure.
1127  * @p:       The memory location to write the data to.
1128  * @return:  Pointer to the byte after the last byte we wrote as part of the
1129  *              dentry.
1130  */
1131 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
1132 {
1133         u8 *orig_p = p;
1134         unsigned padding;
1135
1136         p = put_u64(p, dentry->length);
1137         p = put_u32(p, dentry->attributes);
1138         p = put_u32(p, dentry->security_id);
1139         p = put_u64(p, dentry->subdir_offset);
1140         p = put_u64(p, 0); /* unused1 */
1141         p = put_u64(p, 0); /* unused2 */
1142         p = put_u64(p, dentry->creation_time);
1143         p = put_u64(p, dentry->last_access_time);
1144         p = put_u64(p, dentry->last_write_time);
1145         p = put_bytes(p, WIM_HASH_SIZE, dentry->hash);
1146         if (dentry->attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
1147                 p = put_zeroes(p, 4);
1148                 p = put_u32(p, dentry->reparse_tag);
1149                 p = put_zeroes(p, 4);
1150         } else {
1151                 u64 hard_link;
1152                 p = put_u32(p, dentry->reparse_tag);
1153                 if (dentry->link_group_list.next == &dentry->link_group_list)
1154                         hard_link = 0;
1155                 else
1156                         hard_link = dentry->hard_link;
1157                 p = put_u64(p, hard_link);
1158         }
1159         p = put_u16(p, dentry->num_ads);
1160         p = put_u16(p, dentry->short_name_len);
1161         p = put_u16(p, dentry->file_name_len);
1162         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
1163         p = put_u16(p, 0); /* filename padding, 2 bytes. */
1164         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
1165
1166         wimlib_assert(p - orig_p <= dentry->length);
1167         if (p - orig_p < dentry->length)
1168                 p = put_zeroes(p, dentry->length - (p - orig_p));
1169
1170         p = put_zeroes(p, (8 - (p - orig_p) % 8) % 8);
1171
1172         for (u16 i = 0; i < dentry->num_ads; i++) {
1173                 p = put_u64(p, ads_entry_length(&dentry->ads_entries[i]));
1174                 p = put_u64(p, 0); /* Unused */
1175                 p = put_bytes(p, WIM_HASH_SIZE, dentry->ads_entries[i].hash);
1176                 p = put_u16(p, dentry->ads_entries[i].stream_name_len);
1177                 p = put_bytes(p, dentry->ads_entries[i].stream_name_len,
1178                                  (u8*)dentry->ads_entries[i].stream_name);
1179                 p = put_zeroes(p, (8 - (p - orig_p) % 8) % 8);
1180         }
1181         return p;
1182 }
1183
1184 /* Recursive function that writes a dentry tree rooted at @tree, not including
1185  * @tree itself, which has already been written, except in the case of the root
1186  * dentry, which is written right away, along with an end-of-directory entry. */
1187 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
1188 {
1189         const struct dentry *child;
1190
1191         if (dentry_is_root(tree)) {
1192                 p = write_dentry(tree, p);
1193
1194                 /* write end of directory entry */
1195                 p = put_u64(p, 0);
1196         } else {
1197                 /* Nothing to do for non-directories */
1198                 if (!dentry_is_directory(tree))
1199                         return p;
1200         }
1201
1202         /* Write child dentries and end-of-directory entry. */
1203         child = tree->children;
1204         if (child) {
1205                 do {
1206                         p = write_dentry(child, p);
1207                         child = child->next;
1208                 } while (child != tree->children);
1209         }
1210
1211         /* write end of directory entry */
1212         p = put_u64(p, 0);
1213
1214         /* Recurse on children. */
1215         if (child) {
1216                 do {
1217                         p = write_dentry_tree(child, p);
1218                         child = child->next;
1219                 } while (child != tree->children);
1220         }
1221         return p;
1222 }
1223
1224 /* Reads the children of a dentry, and all their children, ..., etc. from the
1225  * metadata resource and into the dentry tree.
1226  *
1227  * @metadata_resource:  An array that contains the uncompressed metadata
1228  *                      resource for the WIM file.
1229  * @metadata_resource_len:      The length of @metadata_resource.
1230  * @dentry:     A pointer to a struct dentry that is the root of the directory
1231  *              tree and has already been read from the metadata resource.  It
1232  *              does not need to be the real root because this procedure is
1233  *              called recursively.
1234  *
1235  * @return:     Zero on success, nonzero on failure.
1236  */
1237 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
1238                      struct dentry *dentry)
1239 {
1240         u64 cur_offset = dentry->subdir_offset;
1241         struct dentry *prev_child = NULL;
1242         struct dentry *first_child = NULL;
1243         struct dentry *child;
1244         struct dentry cur_child;
1245         int ret;
1246
1247         /* If @dentry is a regular file, nothing more needs to be done for this
1248          * branch. */
1249         if (cur_offset == 0)
1250                 return 0;
1251
1252         /* Find and read all the children of @dentry. */
1253         while (1) {
1254
1255                 /* Read next child of @dentry into @cur_child. */
1256                 ret = read_dentry(metadata_resource, metadata_resource_len,
1257                                   cur_offset, &cur_child);
1258                 if (ret != 0)
1259                         break;
1260
1261                 /* Check for end of directory. */
1262                 if (cur_child.length == 0) {
1263                         ret = 0;
1264                         break;
1265                 }
1266
1267                 /* Not end of directory.  Allocate this child permanently and
1268                  * link it to the parent and previous child. */
1269                 child = MALLOC(sizeof(struct dentry));
1270                 if (!child) {
1271                         ERROR("Failed to allocate %zu bytes for new dentry",
1272                               sizeof(struct dentry));
1273                         ret = WIMLIB_ERR_NOMEM;
1274                         break;
1275                 }
1276                 memcpy(child, &cur_child, sizeof(struct dentry));
1277
1278                 if (prev_child) {
1279                         prev_child->next = child;
1280                         child->prev = prev_child;
1281                 } else {
1282                         first_child = child;
1283                 }
1284
1285                 child->parent = dentry;
1286                 prev_child = child;
1287
1288                 /* If there are children of this child, call this procedure
1289                  * recursively. */
1290                 if (child->subdir_offset != 0) {
1291                         ret = read_dentry_tree(metadata_resource,
1292                                                metadata_resource_len, child);
1293                         if (ret != 0)
1294                                 break;
1295                 }
1296
1297                 /* Advance to the offset of the next child. */
1298                 cur_offset += dentry_total_length(child);
1299         }
1300
1301         /* Link last child to first one, and set parent's
1302          * children pointer to the first child.  */
1303         if (prev_child) {
1304                 prev_child->next = first_child;
1305                 first_child->prev = prev_child;
1306         }
1307         dentry->children = first_child;
1308         return ret;
1309 }