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