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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  * Copyright (C) 2010 Carl Thijssen
  12  * Copyright (C) 2012 Eric Biggers
  13  *
  14  * wimlib - Library for working with WIM files
  15  *
  16  * This library is free software; you can redistribute it and/or modify it under
  17  * the terms of the GNU Lesser General Public License as published by the Free
  18  * Software Foundation; either version 2.1 of the License, or (at your option) any
  19  * later version.
  20  *
  21  * This library is distributed in the hope that it will be useful, but WITHOUT ANY
  22  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
  23  * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
  24  *
  25  * You should have received a copy of the GNU Lesser General Public License along
  26  * with this library; if not, write to the Free Software Foundation, Inc., 59
  27  * Temple Place, Suite 330, Boston, MA 02111-1307 USA
  28  */
  29
  30 #include "wimlib_internal.h"
  31 #include "dentry.h"
  32 #include "io.h"
  33 #include "timestamp.h"
  34 #include "lookup_table.h"
  35 #include "sha1.h"
  36 #include <unistd.h>
  37 #include <sys/stat.h>
  38
  39
  40 /* Transfers file attributes from a `stat' buffer to a struct dentry. */
  41 void stbuf_to_dentry(const struct stat *stbuf, struct dentry *dentry)
  42 {
  43         if (S_ISDIR(stbuf->st_mode))
  44                 dentry->attributes = WIM_FILE_ATTRIBUTE_DIRECTORY;
  45         else
  46                 dentry->attributes = WIM_FILE_ATTRIBUTE_NORMAL;
  47 }
  48
  49 /* Transfers file attributes from a struct dentry to a `stat' buffer. */
  50 void dentry_to_stbuf(const struct dentry *dentry, struct stat *stbuf,
  51                      const struct lookup_table *table)
  52 {
  53         struct lookup_table_entry *lte;
  54
  55         if (dentry_is_directory(dentry))
  56                 stbuf->st_mode = S_IFDIR | 0755;
  57         else
  58                 stbuf->st_mode = S_IFREG | 0644;
  59
  60         if (table)
  61                 lte = lookup_resource(table, dentry->hash);
  62         else
  63                 lte = NULL;
  64
  65         if (lte) {
  66                 stbuf->st_nlink = lte->refcnt;
  67                 stbuf->st_size = lte->resource_entry.original_size;
  68         } else {
  69                 stbuf->st_nlink = 1;
  70                 stbuf->st_size = 0;
  71         }
  72         stbuf->st_uid     = getuid();
  73         stbuf->st_gid     = getgid();
  74         stbuf->st_atime   = ms_timestamp_to_unix(dentry->last_access_time);
  75         stbuf->st_mtime   = ms_timestamp_to_unix(dentry->last_write_time);
  76         stbuf->st_ctime   = ms_timestamp_to_unix(dentry->creation_time);
  77         stbuf->st_blocks  = (stbuf->st_size + 511) / 512;
  78 }
  79
  80 /* Makes all timestamp fields for the dentry be the current time. */
  81 void dentry_update_all_timestamps(struct dentry *dentry)
  82 {
  83         u64 now = get_timestamp();
  84         dentry->creation_time       = now;
  85         dentry->last_access_time    = now;
  86         dentry->last_write_time     = now;
  87 }
  88
  89 /*
  90  * Calls a function on all directory entries in a directory tree.  It is called
  91  * on a parent before its children.
  92  */
  93 int for_dentry_in_tree(struct dentry *root,
  94                        int (*visitor)(struct dentry*, void*), void *arg)
  95 {
  96         int ret;
  97         struct dentry *child;
  98
  99         ret = visitor(root, arg);
 100
 101         if (ret != 0)
 102                 return ret;
 103
 104         child = root->children;
 105
 106         if (!child)
 107                 return 0;
 108
 109         do {
 110                 ret = for_dentry_in_tree(child, visitor, arg);
 111                 if (ret != 0)
 112                         return ret;
 113                 child = child->next;
 114         } while (child != root->children);
 115         return 0;
 116 }
 117
 118 /*
 119  * Like for_dentry_in_tree(), but the visitor function is always called on a
 120  * dentry's children before on itself.
 121  */
 122 int for_dentry_in_tree_depth(struct dentry *root,
 123                              int (*visitor)(struct dentry*, void*), void *arg)
 124 {
 125         int ret;
 126         struct dentry *child;
 127         struct dentry *next;
 128
 129         child = root->children;
 130         if (child) {
 131                 do {
 132                         next = child->next;
 133                         ret = for_dentry_in_tree_depth(child, visitor, arg);
 134                         if (ret != 0)
 135                                 return ret;
 136                         child = next;
 137                 } while (child != root->children);
 138         }
 139         return visitor(root, arg);
 140 }
 141
 142 /*
 143  * Calculate the full path of @dentry, based on its parent's full path and on
 144  * its UTF-8 file name.
 145  */
 146 int calculate_dentry_full_path(struct dentry *dentry, void *ignore)
 147 {
 148         int parent_len;
 149         int len;
 150         char *parent_full_path;
 151         char *full_path;
 152
 153         FREE(dentry->full_path_utf8);
 154
 155         if (dentry_is_root(dentry)) {
 156                 dentry->full_path_utf8 = MALLOC(2);
 157                 if (!dentry->full_path_utf8) {
 158                         ERROR("Out of memory!\n");
 159                         return WIMLIB_ERR_NOMEM;
 160                 }
 161
 162                 dentry->full_path_utf8[0] = '/';
 163                 dentry->full_path_utf8[1] = '\0';
 164                 dentry->full_path_utf8_len = 1;
 165                 return 0;
 166         }
 167
 168         if (dentry_is_root(dentry->parent)) {
 169                 parent_len = 0;
 170                 parent_full_path = "";
 171         } else {
 172                 parent_len = dentry->parent->full_path_utf8_len;
 173                 parent_full_path = dentry->parent->full_path_utf8;
 174         }
 175
 176         len = parent_len + 1 + dentry->file_name_utf8_len;
 177         full_path = MALLOC(len + 1);
 178         if (!full_path) {
 179                 ERROR("Out of memory!\n");
 180                 return WIMLIB_ERR_NOMEM;
 181         }
 182
 183         memcpy(full_path, parent_full_path, parent_len);
 184         full_path[parent_len] = '/';
 185         memcpy(full_path + parent_len + 1, dentry->file_name_utf8,
 186                                 dentry->file_name_utf8_len);
 187         full_path[len] = '\0';
 188         dentry->full_path_utf8 = full_path;
 189         dentry->full_path_utf8_len = len;
 190         return 0;
 191 }
 192
 193 /*
 194  * Recursively calculates the subdir offsets for a directory tree.
 195  *
 196  * @dentry:  The root of the directory tree.
 197  * @subdir_offset_p:  The current subdirectory offset; i.e., the subdirectory
 198  *      offset for @dentry.
 199  */
 200 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
 201 {
 202         struct dentry *child;
 203
 204         child = dentry->children;
 205         dentry->subdir_offset = *subdir_offset_p;
 206         if (child) {
 207
 208                 /* Advance the subdir offset by the amount of space the children
 209                  * of this dentry take up. */
 210                 do {
 211                         *subdir_offset_p += child->length;
 212                         child = child->next;
 213                 } while (child != dentry->children);
 214
 215                 /* End-of-directory dentry on disk. */
 216                 *subdir_offset_p += 8;
 217
 218                 /* Recursively call calculate_subdir_offsets() on all the
 219                  * children. */
 220                 do {
 221                         calculate_subdir_offsets(child, subdir_offset_p);
 222                         child = child->next;
 223                 } while (child != dentry->children);
 224         } else {
 225                 /* On disk, childless directories have a valid subdir_offset
 226                  * that points to an 8-byte end-of-directory dentry.  Regular
 227                  * files have a subdir_offset of 0. */
 228                 if (dentry_is_directory(dentry))
 229                         *subdir_offset_p += 8;
 230                 else
 231                         dentry->subdir_offset = 0;
 232         }
 233 }
 234
 235
 236 /* Returns the child of @dentry that has the file name @name.
 237  * Returns NULL if no child has the name. */
 238 struct dentry *get_dentry_child_with_name(const struct dentry *dentry,
 239                                                         const char *name)
 240 {
 241         struct dentry *child;
 242         size_t name_len;
 243
 244         child = dentry->children;
 245         if (child) {
 246                 name_len = strlen(name);
 247                 do {
 248                         if (dentry_has_name(child, name, name_len))
 249                                 return child;
 250                         child = child->next;
 251                 } while (child != dentry->children);
 252         }
 253         return NULL;
 254 }
 255
 256 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
 257  * @cur_dir.  Returns NULL if no dentry having the path is found. */
 258 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir, const char *path)
 259 {
 260         struct dentry *child;
 261         size_t base_len;
 262         const char *new_path;
 263
 264         if (*path == '\0')
 265                 return cur_dir;
 266
 267         child = cur_dir->children;
 268         if (child) {
 269                 new_path = path_next_part(path, &base_len);
 270                 do {
 271                         if (dentry_has_name(child, path, base_len))
 272                                 return get_dentry_relative_path(child, new_path);
 273                         child = child->next;
 274                 } while (child != cur_dir->children);
 275         }
 276         return NULL;
 277 }
 278
 279 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
 280  * such dentry. */
 281 struct dentry *get_dentry(WIMStruct *w, const char *path)
 282 {
 283         struct dentry *root = wim_root_dentry(w);
 284         while (*path == '/')
 285                 path++;
 286         return get_dentry_relative_path(root, path);
 287 }
 288
 289 /* Returns the parent directory for the @path. */
 290 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
 291 {
 292         size_t path_len = strlen(path);
 293         char buf[path_len + 1];
 294
 295         memcpy(buf, path, path_len + 1);
 296
 297         to_parent_name(buf, path_len);
 298
 299         return get_dentry(w, buf);
 300 }
 301
 302 /* Prints the full path of a dentry. */
 303 int print_dentry_full_path(struct dentry *dentry, void *ignore)
 304 {
 305         if (dentry->full_path_utf8)
 306                 puts(dentry->full_path_utf8);
 307         return 0;
 308 }
 309
 310 /* Prints a directory entry.  @lookup_table is a pointer to the lookup table, or
 311  * NULL if the resource entry for the dentry is not to be printed. */
 312 int print_dentry(struct dentry *dentry, void *lookup_table)
 313 {
 314         struct lookup_table_entry *lte;
 315         printf("[DENTRY]\n");
 316         printf("Length            = %"PRIu64"\n", dentry->length);
 317         printf("Attributes        = 0x%x\n", dentry->attributes);
 318 #ifdef ENABLE_SECURITY_DATA
 319         printf("Security ID       = %d\n", dentry->security_id);
 320 #endif
 321         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
 322         /*printf("Unused1           = %"PRIu64"\n", dentry->unused1);*/
 323         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
 324         printf("Creation Time     = %"PRIu64"\n", dentry->creation_time);
 325         printf("Last Access Time  = %"PRIu64"\n", dentry->last_access_time);
 326         printf("Last Write Time   = %"PRIu64"\n", dentry->last_write_time);
 327         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
 328         printf("Hash              = ");
 329         print_hash(dentry->hash);
 330         putchar('\n');
 331         /*printf("Reparse Tag       = %u\n", dentry->reparse_tag);*/
 332         printf("Hard Link Group   = %"PRIu64"\n", dentry->hard_link);
 333         /*printf("Number of Streams = %hu\n", dentry->streams);*/
 334         printf("Filename          = \"");
 335         print_string(dentry->file_name, dentry->file_name_len);
 336         puts("\"");
 337         printf("Filename Length   = %hu\n", dentry->file_name_len);
 338         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
 339         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
 340         printf("Short Name        = \"");
 341         print_string(dentry->short_name, dentry->short_name_len);
 342         puts("\"");
 343         printf("Short Name Length = %hu\n", dentry->short_name_len);
 344         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
 345         if (lookup_table) {
 346                 lte = lookup_resource(lookup_table, dentry->hash);
 347                 if (lte)
 348                         print_lookup_table_entry(lte, NULL);
 349                 else
 350                         putchar('\n');
 351         } else {
 352                 putchar('\n');
 353         }
 354         return 0;
 355 }
 356
 357 static inline void dentry_common_init(struct dentry *dentry)
 358 {
 359         memset(dentry, 0, sizeof(struct dentry));
 360         dentry->refcnt = 1;
 361 #ifdef ENABLE_SECURITY_DATA
 362         dentry->security_id = -1;
 363 #endif
 364 }
 365
 366 /*
 367  * Creates an unlinked directory entry.
 368  *
 369  * @name:    The base name of the new dentry.
 370  * @return:  A pointer to the new dentry, or NULL if out of memory.
 371  */
 372 struct dentry *new_dentry(const char *name)
 373 {
 374         struct dentry *dentry;
 375
 376         dentry = MALLOC(sizeof(struct dentry));
 377         if (!dentry)
 378                 return NULL;
 379
 380         dentry_common_init(dentry);
 381         if (change_dentry_name(dentry, name) != 0) {
 382                 FREE(dentry);
 383                 return NULL;
 384         }
 385
 386         dentry_update_all_timestamps(dentry);
 387         dentry->next   = dentry;
 388         dentry->prev   = dentry;
 389         dentry->parent = dentry;
 390         return dentry;
 391 }
 392
 393
 394 void free_dentry(struct dentry *dentry)
 395 {
 396         FREE(dentry->file_name);
 397         FREE(dentry->file_name_utf8);
 398         FREE(dentry->short_name);
 399         FREE(dentry->full_path_utf8);
 400         FREE(dentry);
 401 }
 402
 403 /* Arguments for do_free_dentry(). */
 404 struct free_dentry_args {
 405         struct lookup_table *lookup_table;
 406         bool decrement_refcnt;
 407 };
 408
 409 /*
 410  * This function is passed as an argument to for_dentry_in_tree_depth() in order
 411  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
 412  */
 413 static int do_free_dentry(struct dentry *dentry, void *__args)
 414 {
 415         struct free_dentry_args *args = (struct free_dentry_args*)__args;
 416
 417         if (args->decrement_refcnt && !dentry_is_directory(dentry)) {
 418                 lookup_table_decrement_refcnt(args->lookup_table,
 419                                               dentry->hash);
 420         }
 421
 422         wimlib_assert(dentry->refcnt >= 1);
 423         if (--dentry->refcnt == 0)
 424                 free_dentry(dentry);
 425         return 0;
 426 }
 427
 428 /*
 429  * Unlinks and frees a dentry tree.
 430  *
 431  * @root:               The root of the tree.
 432  * @lookup_table:       The lookup table for dentries.
 433  * @decrement_refcnt:   True if the dentries in the tree are to have their
 434  *                      reference counts in the lookup table decremented.
 435  */
 436 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table,
 437                       bool decrement_refcnt)
 438 {
 439         if (!root || !root->parent)
 440                 return;
 441
 442         struct free_dentry_args args;
 443         args.lookup_table        = lookup_table;
 444         args.decrement_refcnt    = decrement_refcnt;
 445         for_dentry_in_tree_depth(root, do_free_dentry, &args);
 446 }
 447
 448 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
 449 {
 450         dentry->refcnt++;
 451         return 0;
 452 }
 453
 454 /*
 455  * Links a dentry into the directory tree.
 456  *
 457  * @dentry: The dentry to link.
 458  * @parent: The dentry that will be the parent of @dentry.
 459  */
 460 void link_dentry(struct dentry *dentry, struct dentry *parent)
 461 {
 462         dentry->parent = parent;
 463         if (parent->children) {
 464                 /* Not an only child; link to siblings. */
 465                 dentry->next = parent->children;
 466                 dentry->prev = parent->children->prev;
 467                 dentry->next->prev = dentry;
 468                 dentry->prev->next = dentry;
 469         } else {
 470                 /* Only child; link to parent. */
 471                 parent->children = dentry;
 472                 dentry->next = dentry;
 473                 dentry->prev = dentry;
 474         }
 475 }
 476
 477 /* Unlink a dentry from the directory tree. */
 478 void unlink_dentry(struct dentry *dentry)
 479 {
 480         if (dentry_is_root(dentry))
 481                 return;
 482         if (dentry_is_only_child(dentry)) {
 483                 dentry->parent->children = NULL;
 484         } else {
 485                 if (dentry_is_first_sibling(dentry))
 486                         dentry->parent->children = dentry->next;
 487                 dentry->next->prev = dentry->prev;
 488                 dentry->prev->next = dentry->next;
 489         }
 490 }
 491
 492
 493 /* Recalculates the length of @dentry based on its file name length and short
 494  * name length.  */
 495 static inline void recalculate_dentry_size(struct dentry *dentry)
 496 {
 497         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len +
 498                          2 + dentry->short_name_len;
 499         /* Must be multiple of 8. */
 500         dentry->length += (8 - dentry->length % 8) % 8;
 501 }
 502
 503 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
 504  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
 505  * full_path_utf8 fields.  Also recalculates its length. */
 506 int change_dentry_name(struct dentry *dentry, const char *new_name)
 507 {
 508         size_t utf8_len;
 509         size_t utf16_len;
 510
 511         FREE(dentry->file_name);
 512
 513         utf8_len = strlen(new_name);
 514
 515         dentry->file_name = utf8_to_utf16(new_name, utf8_len, &utf16_len);
 516
 517         if (!dentry->file_name)
 518                 return WIMLIB_ERR_NOMEM;
 519
 520         FREE(dentry->file_name_utf8);
 521         dentry->file_name_utf8 = MALLOC(utf8_len + 1);
 522         if (!dentry->file_name_utf8) {
 523                 FREE(dentry->file_name);
 524                 dentry->file_name = NULL;
 525                 return WIMLIB_ERR_NOMEM;
 526         }
 527
 528         dentry->file_name_len = utf16_len;
 529         dentry->file_name_utf8_len = utf8_len;
 530         memcpy(dentry->file_name_utf8, new_name, utf8_len + 1);
 531         recalculate_dentry_size(dentry);
 532         return 0;
 533 }
 534
 535 /* Parameters for calculate_dentry_statistics(). */
 536 struct image_statistics {
 537         struct lookup_table *lookup_table;
 538         u64 *dir_count;
 539         u64 *file_count;
 540         u64 *total_bytes;
 541         u64 *hard_link_bytes;
 542 };
 543
 544 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
 545 {
 546         struct image_statistics *stats;
 547         struct lookup_table_entry *lte;
 548
 549         stats = arg;
 550         lte = lookup_resource(stats->lookup_table, dentry->hash);
 551
 552         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
 553                 ++*stats->dir_count;
 554         else
 555                 ++*stats->file_count;
 556
 557         if (lte) {
 558                 u64 size = lte->resource_entry.original_size;
 559                 *stats->total_bytes += size;
 560                 if (++lte->out_refcnt == 1)
 561                         *stats->hard_link_bytes += size;
 562         }
 563         return 0;
 564 }
 565
 566 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
 567                                    u64 *dir_count_ret, u64 *file_count_ret,
 568                                    u64 *total_bytes_ret,
 569                                    u64 *hard_link_bytes_ret)
 570 {
 571         struct image_statistics stats;
 572         *dir_count_ret         = 0;
 573         *file_count_ret        = 0;
 574         *total_bytes_ret       = 0;
 575         *hard_link_bytes_ret   = 0;
 576         stats.lookup_table     = table;
 577         stats.dir_count       = dir_count_ret;
 578         stats.file_count      = file_count_ret;
 579         stats.total_bytes     = total_bytes_ret;
 580         stats.hard_link_bytes = hard_link_bytes_ret;
 581         for_lookup_table_entry(table, zero_out_refcnts, NULL);
 582         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
 583 }
 584
 585 /*
 586  * Reads a directory entry from the metadata resource.
 587  */
 588 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
 589                                         u64 offset, struct dentry *dentry)
 590 {
 591         const u8 *p;
 592         u64 calculated_size;
 593         char *file_name;
 594         char *file_name_utf8;
 595         char *short_name;
 596         u16 short_name_len;
 597         u16 file_name_len;
 598         size_t file_name_utf8_len;
 599
 600         dentry_common_init(dentry);
 601
 602         /*Make sure the dentry really fits into the metadata resource.*/
 603         if (offset + 8 > metadata_resource_len) {
 604                 ERROR("Directory entry starting at %"PRIu64" ends past the "
 605                         "end of the metadata resource (size %"PRIu64")!\n",
 606                         offset, metadata_resource_len);
 607                 return WIMLIB_ERR_INVALID_DENTRY;
 608         }
 609
 610         /* Before reading the whole entry, we need to read just the length.
 611          * This is because an entry of length 8 (that is, just the length field)
 612          * terminates the list of sibling directory entries. */
 613
 614         p = get_u64(&metadata_resource[offset], &dentry->length);
 615
 616         /* A zero length field (really a length of 8, since that's how big the
 617          * directory entry is...) indicates that this is the end of directory
 618          * dentry.  We do not read it into memory as an actual dentry, so just
 619          * return true in that case. */
 620         if (dentry->length == 0)
 621                 return 0;
 622
 623         if (offset + dentry->length >= metadata_resource_len) {
 624                 ERROR("Directory entry at offset %"PRIu64" and with size "
 625                                 "%"PRIu64" ends past the end of the metadata resource "
 626                                 "(size %"PRIu64")!\n", offset, dentry->length,
 627                                 metadata_resource_len);
 628                 return WIMLIB_ERR_INVALID_DENTRY;
 629         }
 630
 631         /* If it is a recognized length, read the rest of the directory entry.
 632          * Note: The root directory entry has no name, and its length does not
 633          * include the short name length field.  */
 634         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
 635                 ERROR("Directory entry has invalid length of "
 636                                 "%"PRIu64" bytes\n", dentry->length);
 637                 return WIMLIB_ERR_INVALID_DENTRY;
 638         }
 639
 640         p = get_u32(p, &dentry->attributes);
 641 #ifdef ENABLE_SECURITY_DATA
 642         p = get_u32(p, &dentry->security_id);
 643 #else
 644         p += sizeof(u32);
 645 #endif
 646         p = get_u64(p, &dentry->subdir_offset);
 647
 648         /* 2 unused fields */
 649         p += 2 * sizeof(u64);
 650
 651         p = get_u64(p, &dentry->creation_time);
 652         p = get_u64(p, &dentry->last_access_time);
 653         p = get_u64(p, &dentry->last_write_time);
 654
 655         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
 656
 657         /* Currently ignoring reparse_tag. */
 658         p += sizeof(u32);
 659
 660         /* The reparse_reserved field does not actually exist. */
 661
 662         p = get_u64(p, &dentry->hard_link);
 663
 664         /* Currently ignoring streams. */
 665         p += sizeof(u16);
 666
 667         p = get_u16(p, &short_name_len);
 668         p = get_u16(p, &file_name_len);
 669
 670         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
 671                           short_name_len;
 672
 673         if (dentry->length < calculated_size) {
 674                 ERROR("Unexpected end of directory entry! (Expected "
 675                                 "%"PRIu64" bytes, got %"PRIu64" bytes. "
 676                                 "short_name_len = %hu, file_name_len = %hu)\n",
 677                                 calculated_size, dentry->length,
 678                                 short_name_len, file_name_len);
 679                 return WIMLIB_ERR_INVALID_DENTRY;
 680         }
 681
 682         /* Read the filename. */
 683         file_name = MALLOC(file_name_len);
 684         if (!file_name) {
 685                 ERROR("Failed to allocate %hu bytes for dentry file name!\n",
 686                                 file_name_len);
 687                 return WIMLIB_ERR_NOMEM;
 688         }
 689         p = get_bytes(p, file_name_len, file_name);
 690
 691         /* Convert filename to UTF-8. */
 692         file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
 693                                        &file_name_utf8_len);
 694
 695         if (!file_name_utf8) {
 696                 ERROR("Failed to allocate memory to convert UTF16 "
 697                                 "filename (%hu bytes) to UTF8\n",
 698                                 file_name_len);
 699                 goto err_nomem2;
 700         }
 701
 702         /* Undocumented padding between file name and short name.  This probably
 703          * is supposed to be a terminating NULL character. */
 704         p += 2;
 705
 706         /* Read the short filename. */
 707         short_name = MALLOC(short_name_len);
 708         if (!short_name) {
 709                 ERROR("Failed to allocate %hu bytes for short filename\n",
 710                                 short_name_len);
 711                 goto err_nomem1;
 712         }
 713
 714         get_bytes(p, short_name_len, short_name);
 715
 716         dentry->file_name          = file_name;
 717         dentry->file_name_utf8     = file_name_utf8;
 718         dentry->short_name         = short_name;
 719         dentry->file_name_len      = file_name_len;
 720         dentry->file_name_utf8_len = file_name_utf8_len;
 721         dentry->short_name_len     = short_name_len;
 722         return 0;
 723 err_nomem1:
 724         FREE(dentry->file_name_utf8);
 725 err_nomem2:
 726         FREE(dentry->file_name);
 727         return WIMLIB_ERR_NOMEM;
 728 }
 729
 730 /*
 731  * Writes a dentry to an output buffer.
 732  *
 733  * @dentry:  The dentry structure.
 734  * @p:       The memory location to write the data to.
 735  * @return:  True on success, false on failure.
 736  */
 737 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
 738 {
 739         u8 *orig_p = p;
 740         memset(p, 0, dentry->length);
 741         p = put_u64(p, dentry->length);
 742         p = put_u32(p, dentry->attributes);
 743 #ifdef ENABLE_SECURITY_DATA
 744         p = put_u32(p, dentry->security_id);
 745 #else
 746         p = put_u32(p, (u32)(-1));
 747 #endif
 748         p = put_u64(p, dentry->subdir_offset);
 749         p = put_u64(p, 0); /* unused1 */
 750         p = put_u64(p, 0); /* unused2 */
 751         p = put_u64(p, dentry->creation_time);
 752         p = put_u64(p, dentry->last_access_time);
 753         p = put_u64(p, dentry->last_write_time);
 754         if (!is_empty_file_hash(dentry->hash))
 755                 memcpy(p, dentry->hash, WIM_HASH_SIZE);
 756         else
 757                 printf("zero hash for %s\n", dentry->file_name_utf8);
 758         p += WIM_HASH_SIZE;
 759         p = put_u32(p, 0); /* reparse_tag */
 760         p = put_u64(p, dentry->hard_link);
 761         p = put_u16(p, 0); /*streams */
 762         p = put_u16(p, dentry->short_name_len);
 763         p = put_u16(p, dentry->file_name_len);
 764         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
 765         p = put_u16(p, 0); /* filename padding, 2 bytes. */
 766         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
 767         return orig_p + dentry->length;
 768 }
 769
 770 /* Recursive function that writes a dentry tree rooted at @tree, not including
 771  * @tree itself, which has already been written, except in the case of the root
 772  * dentry, which is written right away, along with an end-of-directory entry. */
 773 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
 774 {
 775         const struct dentry *child;
 776
 777         if (dentry_is_root(tree)) {
 778                 p = write_dentry(tree, p);
 779
 780                 /* write end of directory entry */
 781                 p = put_u64(p, 0);
 782         } else {
 783                 /* Nothing to do for a regular file. */
 784                 if (dentry_is_regular_file(tree))
 785                         return p;
 786         }
 787
 788         /* Write child dentries and end-of-directory entry. */
 789         child = tree->children;
 790         if (child) {
 791                 do {
 792                         p = write_dentry(child, p);
 793                         child = child->next;
 794                 } while (child != tree->children);
 795         }
 796
 797         /* write end of directory entry */
 798         p = put_u64(p, 0);
 799
 800         /* Recurse on children. */
 801         if (child) {
 802                 do {
 803                         p = write_dentry_tree(child, p);
 804                         child = child->next;
 805                 } while (child != tree->children);
 806         }
 807         return p;
 808 }
 809
 810 /* Reads the children of a dentry, and all their children, ..., etc. from the
 811  * metadata resource and into the dentry tree.
 812  *
 813  * @metadata_resource:  An array that contains the uncompressed metadata
 814  *                              resource for the WIM file.
 815  * @metadata_resource_len:      The length of @metadata_resource.
 816  * @dentry:     A pointer to a struct dentry that is the root of the directory tree
 817  *              and has already been read from the metadata resource.  It does not
 818  *              need to be the real root, because this procedure is called
 819  *              recursively.
 820  * @return:     True on success, false on failure.
 821  */
 822 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 823                      struct dentry *dentry)
 824 {
 825         u64 cur_offset = dentry->subdir_offset;
 826         struct dentry *prev_child = NULL;
 827         struct dentry *first_child = NULL;
 828         struct dentry *child;
 829         struct dentry cur_child;
 830         int ret;
 831
 832         /* If @dentry is a regular file, nothing more needs to be done for this
 833          * branch. */
 834         if (cur_offset == 0)
 835                 return 0;
 836
 837         /* Find and read all the children of @dentry. */
 838         while (1) {
 839
 840                 /* Read next child of @dentry into @cur_child. */
 841                 ret = read_dentry(metadata_resource, metadata_resource_len,
 842                                   cur_offset, &cur_child);
 843                 if (ret != 0)
 844                         break;
 845
 846                 /* Check for end of directory. */
 847                 if (cur_child.length == 0) {
 848                         ret = 0;
 849                         break;
 850                 }
 851
 852                 /* Not end of directory.  Allocate this child permanently and
 853                  * link it to the parent and previous child. */
 854                 child = MALLOC(sizeof(struct dentry));
 855                 if (!child) {
 856                         ERROR("Failed to allocate %zu bytes for new dentry!\n",
 857                                         sizeof(struct dentry));
 858                         ret = WIMLIB_ERR_NOMEM;
 859                         break;
 860                 }
 861                 memcpy(child, &cur_child, sizeof(struct dentry));
 862
 863                 if (prev_child) {
 864                         prev_child->next = child;
 865                         child->prev = prev_child;
 866                 } else {
 867                         first_child = child;
 868                 }
 869
 870                 child->parent = dentry;
 871                 prev_child = child;
 872
 873                 /* If there are children of this child, call this procedure
 874                  * recursively. */
 875                 if (child->subdir_offset != 0) {
 876                         ret = read_dentry_tree(metadata_resource,
 877                                                metadata_resource_len, child);
 878                         if (ret != 0)
 879                                 break;
 880                 }
 881
 882                 /* Advance to the offset of the next child. */
 883                 cur_offset += child->length;
 884         }
 885
 886         /* Link last child to first one, and set parent's
 887          * children pointer to the first child.  */
 888         if (prev_child) {
 889                 prev_child->next = first_child;
 890                 first_child->prev = prev_child;
 891         }
 892         dentry->children = first_child;
 893         return ret;
 894 }