wimlib.net Git - wimlib/blob - src/dentry.c

   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 <unistd.h>
  40 #include <sys/stat.h>
  41
  42
  43 /* Transfers file attributes from a `stat' buffer to a struct dentry. */
  44 void stbuf_to_dentry(const struct stat *stbuf, struct dentry *dentry)
  45 {
  46         if (S_ISDIR(stbuf->st_mode))
  47                 dentry->attributes = WIM_FILE_ATTRIBUTE_DIRECTORY;
  48         else
  49                 dentry->attributes = WIM_FILE_ATTRIBUTE_NORMAL;
  50 }
  51
  52 /* Transfers file attributes from a struct dentry to a `stat' buffer. */
  53 void dentry_to_stbuf(const struct dentry *dentry, struct stat *stbuf,
  54                      const struct lookup_table *table)
  55 {
  56         struct lookup_table_entry *lte;
  57
  58         if (dentry_is_directory(dentry))
  59                 stbuf->st_mode = S_IFDIR | 0755;
  60         else
  61                 stbuf->st_mode = S_IFREG | 0644;
  62
  63         if (table)
  64                 lte = lookup_resource(table, dentry->hash);
  65         else
  66                 lte = NULL;
  67
  68         if (lte) {
  69                 stbuf->st_nlink = lte->refcnt;
  70                 stbuf->st_size = lte->resource_entry.original_size;
  71         } else {
  72                 stbuf->st_nlink = 1;
  73                 stbuf->st_size = 0;
  74         }
  75         stbuf->st_uid     = getuid();
  76         stbuf->st_gid     = getgid();
  77         stbuf->st_atime   = ms_timestamp_to_unix(dentry->last_access_time);
  78         stbuf->st_mtime   = ms_timestamp_to_unix(dentry->last_write_time);
  79         stbuf->st_ctime   = ms_timestamp_to_unix(dentry->creation_time);
  80         stbuf->st_blocks  = (stbuf->st_size + 511) / 512;
  81 }
  82
  83 /* Makes all timestamp fields for the dentry be the current time. */
  84 void dentry_update_all_timestamps(struct dentry *dentry)
  85 {
  86         u64 now = get_timestamp();
  87         dentry->creation_time    = now;
  88         dentry->last_access_time = now;
  89         dentry->last_write_time  = now;
  90 }
  91
  92 /*
  93  * Calls a function on all directory entries in a directory tree.  It is called
  94  * on a parent before its children.
  95  */
  96 int for_dentry_in_tree(struct dentry *root,
  97                        int (*visitor)(struct dentry*, void*), void *arg)
  98 {
  99         int ret;
 100         struct dentry *child;
 101
 102         ret = visitor(root, arg);
 103
 104         if (ret != 0)
 105                 return ret;
 106
 107         child = root->children;
 108
 109         if (!child)
 110                 return 0;
 111
 112         do {
 113                 ret = for_dentry_in_tree(child, visitor, arg);
 114                 if (ret != 0)
 115                         return ret;
 116                 child = child->next;
 117         } while (child != root->children);
 118         return 0;
 119 }
 120
 121 /*
 122  * Like for_dentry_in_tree(), but the visitor function is always called on a
 123  * dentry's children before on itself.
 124  */
 125 int for_dentry_in_tree_depth(struct dentry *root,
 126                              int (*visitor)(struct dentry*, void*), void *arg)
 127 {
 128         int ret;
 129         struct dentry *child;
 130         struct dentry *next;
 131
 132         child = root->children;
 133         if (child) {
 134                 do {
 135                         next = child->next;
 136                         ret = for_dentry_in_tree_depth(child, visitor, arg);
 137                         if (ret != 0)
 138                                 return ret;
 139                         child = next;
 140                 } while (child != root->children);
 141         }
 142         return visitor(root, arg);
 143 }
 144
 145 /*
 146  * Calculate the full path of @dentry, based on its parent's full path and on
 147  * its UTF-8 file name.
 148  */
 149 int calculate_dentry_full_path(struct dentry *dentry, void *ignore)
 150 {
 151         char *full_path;
 152         u32 full_path_len;
 153         if (dentry_is_root(dentry)) {
 154                 full_path = MALLOC(2);
 155                 if (!full_path)
 156                         goto oom;
 157                 full_path[0] = '/';
 158                 full_path[1] = '\0';
 159                 full_path_len = 1;
 160         } else {
 161                 char *parent_full_path;
 162                 u32 parent_full_path_len;
 163                 const struct dentry *parent = dentry->parent;
 164
 165                 if (dentry_is_root(parent)) {
 166                         parent_full_path = "";
 167                         parent_full_path_len = 0;
 168                 } else {
 169                         parent_full_path = parent->full_path_utf8;
 170                         parent_full_path_len = parent->full_path_utf8_len;
 171                 }
 172
 173                 full_path_len = parent_full_path_len + 1 +
 174                                 dentry->file_name_utf8_len;
 175                 full_path = MALLOC(full_path_len + 1);
 176                 if (!full_path)
 177                         goto oom;
 178
 179                 memcpy(full_path, parent_full_path, parent_full_path_len);
 180                 full_path[parent_full_path_len] = '/';
 181                 memcpy(full_path + parent_full_path_len + 1,
 182                        dentry->file_name_utf8,
 183                        dentry->file_name_utf8_len);
 184                 full_path[full_path_len] = '\0';
 185         }
 186         FREE(dentry->full_path_utf8);
 187         dentry->full_path_utf8 = full_path;
 188         dentry->full_path_utf8_len = full_path_len;
 189         return 0;
 190 oom:
 191         ERROR("Out of memory while calculating dentry full path");
 192         return WIMLIB_ERR_NOMEM;
 193 }
 194
 195 /*
 196  * Recursively calculates the subdir offsets for a directory tree.
 197  *
 198  * @dentry:  The root of the directory tree.
 199  * @subdir_offset_p:  The current subdirectory offset; i.e., the subdirectory
 200  *      offset for @dentry.
 201  */
 202 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
 203 {
 204         struct dentry *child;
 205
 206         child = dentry->children;
 207         dentry->subdir_offset = *subdir_offset_p;
 208         if (child) {
 209
 210                 /* Advance the subdir offset by the amount of space the children
 211                  * of this dentry take up. */
 212                 do {
 213                         *subdir_offset_p += child->length;
 214                         child = child->next;
 215                 } while (child != dentry->children);
 216
 217                 /* End-of-directory dentry on disk. */
 218                 *subdir_offset_p += 8;
 219
 220                 /* Recursively call calculate_subdir_offsets() on all the
 221                  * children. */
 222                 do {
 223                         calculate_subdir_offsets(child, subdir_offset_p);
 224                         child = child->next;
 225                 } while (child != dentry->children);
 226         } else {
 227                 /* On disk, childless directories have a valid subdir_offset
 228                  * that points to an 8-byte end-of-directory dentry.  Regular
 229                  * files have a subdir_offset of 0. */
 230                 if (dentry_is_directory(dentry))
 231                         *subdir_offset_p += 8;
 232                 else
 233                         dentry->subdir_offset = 0;
 234         }
 235 }
 236
 237
 238 /* Returns the child of @dentry that has the file name @name.
 239  * Returns NULL if no child has the name. */
 240 struct dentry *get_dentry_child_with_name(const struct dentry *dentry,
 241                                                         const char *name)
 242 {
 243         struct dentry *child;
 244         size_t name_len;
 245
 246         child = dentry->children;
 247         if (child) {
 248                 name_len = strlen(name);
 249                 do {
 250                         if (dentry_has_name(child, name, name_len))
 251                                 return child;
 252                         child = child->next;
 253                 } while (child != dentry->children);
 254         }
 255         return NULL;
 256 }
 257
 258 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
 259  * @cur_dir.  Returns NULL if no dentry having the path is found. */
 260 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir, const char *path)
 261 {
 262         struct dentry *child;
 263         size_t base_len;
 264         const char *new_path;
 265
 266         if (*path == '\0')
 267                 return cur_dir;
 268
 269         child = cur_dir->children;
 270         if (child) {
 271                 new_path = path_next_part(path, &base_len);
 272                 do {
 273                         if (dentry_has_name(child, path, base_len))
 274                                 return get_dentry_relative_path(child, new_path);
 275                         child = child->next;
 276                 } while (child != cur_dir->children);
 277         }
 278         return NULL;
 279 }
 280
 281 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
 282  * such dentry. */
 283 struct dentry *get_dentry(WIMStruct *w, const char *path)
 284 {
 285         struct dentry *root = wim_root_dentry(w);
 286         while (*path == '/')
 287                 path++;
 288         return get_dentry_relative_path(root, path);
 289 }
 290
 291 /* Returns the parent directory for the @path. */
 292 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
 293 {
 294         size_t path_len = strlen(path);
 295         char buf[path_len + 1];
 296
 297         memcpy(buf, path, path_len + 1);
 298
 299         to_parent_name(buf, path_len);
 300
 301         return get_dentry(w, buf);
 302 }
 303
 304 /* Prints the full path of a dentry. */
 305 int print_dentry_full_path(struct dentry *dentry, void *ignore)
 306 {
 307         if (dentry->full_path_utf8)
 308                 puts(dentry->full_path_utf8);
 309         return 0;
 310 }
 311
 312 struct file_attr_flag {
 313         u32 flag;
 314         const char *name;
 315 };
 316 struct file_attr_flag file_attr_flags[] = {
 317         {WIM_FILE_ATTRIBUTE_READONLY,           "READONLY"},
 318         {WIM_FILE_ATTRIBUTE_HIDDEN,             "HIDDEN"},
 319         {WIM_FILE_ATTRIBUTE_SYSTEM,             "SYSTEM"},
 320         {WIM_FILE_ATTRIBUTE_DIRECTORY,          "DIRECTORY"},
 321         {WIM_FILE_ATTRIBUTE_ARCHIVE,            "ARCHIVE"},
 322         {WIM_FILE_ATTRIBUTE_DEVICE,             "DEVICE"},
 323         {WIM_FILE_ATTRIBUTE_NORMAL,             "NORMAL"},
 324         {WIM_FILE_ATTRIBUTE_TEMPORARY,          "TEMPORARY"},
 325         {WIM_FILE_ATTRIBUTE_SPARSE_FILE,        "SPARSE_FILE"},
 326         {WIM_FILE_ATTRIBUTE_REPARSE_POINT,      "REPARSE_POINT"},
 327         {WIM_FILE_ATTRIBUTE_COMPRESSED,         "COMPRESSED"},
 328         {WIM_FILE_ATTRIBUTE_OFFLINE,            "OFFLINE"},
 329         {WIM_FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,"NOT_CONTENT_INDEXED"},
 330         {WIM_FILE_ATTRIBUTE_ENCRYPTED,          "ENCRYPTED"},
 331         {WIM_FILE_ATTRIBUTE_VIRTUAL,            "VIRTUAL"},
 332 };
 333
 334 /* Prints a directory entry.  @lookup_table is a pointer to the lookup table, or
 335  * NULL if the resource entry for the dentry is not to be printed. */
 336 int print_dentry(struct dentry *dentry, void *lookup_table)
 337 {
 338         struct lookup_table_entry *lte;
 339         unsigned i;
 340
 341         printf("[DENTRY]\n");
 342         printf("Length            = %"PRIu64"\n", dentry->length);
 343         printf("Attributes        = 0x%x\n", dentry->attributes);
 344         for (i = 0; i < ARRAY_LEN(file_attr_flags); i++)
 345                 if (file_attr_flags[i].flag & dentry->attributes)
 346                         printf("    WIM_FILE_ATTRIBUTE_%s is set\n",
 347                                 file_attr_flags[i].name);
 348 #ifdef ENABLE_SECURITY_DATA
 349         printf("Security ID       = %d\n", dentry->security_id);
 350 #endif
 351         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
 352         /*printf("Unused1           = %"PRIu64"\n", dentry->unused1);*/
 353         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
 354         printf("Creation Time     = %"PRIu64"\n", dentry->creation_time);
 355         printf("Last Access Time  = %"PRIu64"\n", dentry->last_access_time);
 356         printf("Last Write Time   = %"PRIu64"\n", dentry->last_write_time);
 357         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
 358         printf("Hash              = ");
 359         print_hash(dentry->hash);
 360         putchar('\n');
 361         /*printf("Reparse Tag       = %u\n", dentry->reparse_tag);*/
 362         printf("Hard Link Group   = %"PRIu64"\n", dentry->hard_link);
 363         /*printf("Number of Streams = %hu\n", dentry->streams);*/
 364         printf("Filename          = \"");
 365         print_string(dentry->file_name, dentry->file_name_len);
 366         puts("\"");
 367         printf("Filename Length   = %hu\n", dentry->file_name_len);
 368         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
 369         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
 370         printf("Short Name        = \"");
 371         print_string(dentry->short_name, dentry->short_name_len);
 372         puts("\"");
 373         printf("Short Name Length = %hu\n", dentry->short_name_len);
 374         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
 375         if (lookup_table) {
 376                 lte = lookup_resource(lookup_table, dentry->hash);
 377                 if (lte)
 378                         print_lookup_table_entry(lte, NULL);
 379                 else
 380                         putchar('\n');
 381         } else {
 382                 putchar('\n');
 383         }
 384         return 0;
 385 }
 386
 387 static inline void dentry_common_init(struct dentry *dentry)
 388 {
 389         memset(dentry, 0, sizeof(struct dentry));
 390         dentry->refcnt = 1;
 391 }
 392
 393 /*
 394  * Creates an unlinked directory entry.
 395  *
 396  * @name:    The base name of the new dentry.
 397  * @return:  A pointer to the new dentry, or NULL if out of memory.
 398  */
 399 struct dentry *new_dentry(const char *name)
 400 {
 401         struct dentry *dentry;
 402
 403         dentry = MALLOC(sizeof(struct dentry));
 404         if (!dentry)
 405                 return NULL;
 406
 407         dentry_common_init(dentry);
 408         if (change_dentry_name(dentry, name) != 0) {
 409                 FREE(dentry);
 410                 return NULL;
 411         }
 412
 413         dentry_update_all_timestamps(dentry);
 414         dentry->next   = dentry;
 415         dentry->prev   = dentry;
 416         dentry->parent = dentry;
 417         return dentry;
 418 }
 419
 420
 421 void free_dentry(struct dentry *dentry)
 422 {
 423         FREE(dentry->file_name);
 424         FREE(dentry->file_name_utf8);
 425         FREE(dentry->short_name);
 426         FREE(dentry->full_path_utf8);
 427         FREE(dentry);
 428 }
 429
 430 /* Arguments for do_free_dentry(). */
 431 struct free_dentry_args {
 432         struct lookup_table *lookup_table;
 433         bool lt_decrement_refcnt;
 434 };
 435
 436 /*
 437  * This function is passed as an argument to for_dentry_in_tree_depth() in order
 438  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
 439  */
 440 static int do_free_dentry(struct dentry *dentry, void *__args)
 441 {
 442         struct free_dentry_args *args = (struct free_dentry_args*)__args;
 443
 444         if (args->lt_decrement_refcnt && !dentry_is_directory(dentry)) {
 445                 lookup_table_decrement_refcnt(args->lookup_table,
 446                                               dentry->hash);
 447         }
 448
 449         wimlib_assert(dentry->refcnt >= 1);
 450         if (--dentry->refcnt == 0)
 451                 free_dentry(dentry);
 452         return 0;
 453 }
 454
 455 /*
 456  * Unlinks and frees a dentry tree.
 457  *
 458  * @root:               The root of the tree.
 459  * @lookup_table:       The lookup table for dentries.
 460  * @decrement_refcnt:   True if the dentries in the tree are to have their
 461  *                      reference counts in the lookup table decremented.
 462  */
 463 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table,
 464                       bool lt_decrement_refcnt)
 465 {
 466         if (!root || !root->parent)
 467                 return;
 468
 469         struct free_dentry_args args;
 470         args.lookup_table        = lookup_table;
 471         args.lt_decrement_refcnt = lt_decrement_refcnt;
 472         for_dentry_in_tree_depth(root, do_free_dentry, &args);
 473 }
 474
 475 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
 476 {
 477         dentry->refcnt++;
 478         return 0;
 479 }
 480
 481 /*
 482  * Links a dentry into the directory tree.
 483  *
 484  * @dentry: The dentry to link.
 485  * @parent: The dentry that will be the parent of @dentry.
 486  */
 487 void link_dentry(struct dentry *dentry, struct dentry *parent)
 488 {
 489         dentry->parent = parent;
 490         if (parent->children) {
 491                 /* Not an only child; link to siblings. */
 492                 dentry->next = parent->children;
 493                 dentry->prev = parent->children->prev;
 494                 dentry->next->prev = dentry;
 495                 dentry->prev->next = dentry;
 496         } else {
 497                 /* Only child; link to parent. */
 498                 parent->children = dentry;
 499                 dentry->next = dentry;
 500                 dentry->prev = dentry;
 501         }
 502 }
 503
 504 /* Unlink a dentry from the directory tree. */
 505 void unlink_dentry(struct dentry *dentry)
 506 {
 507         if (dentry_is_root(dentry))
 508                 return;
 509         if (dentry_is_only_child(dentry)) {
 510                 dentry->parent->children = NULL;
 511         } else {
 512                 if (dentry_is_first_sibling(dentry))
 513                         dentry->parent->children = dentry->next;
 514                 dentry->next->prev = dentry->prev;
 515                 dentry->prev->next = dentry->next;
 516         }
 517 }
 518
 519
 520 /* Recalculates the length of @dentry based on its file name length and short
 521  * name length.  */
 522 static inline void recalculate_dentry_size(struct dentry *dentry)
 523 {
 524         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len +
 525                          2 + dentry->short_name_len;
 526         /* Must be multiple of 8. */
 527         dentry->length += (8 - dentry->length % 8) % 8;
 528 }
 529
 530 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
 531  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
 532  * full_path_utf8 fields.  Also recalculates its length. */
 533 int change_dentry_name(struct dentry *dentry, const char *new_name)
 534 {
 535         size_t utf8_len;
 536         size_t utf16_len;
 537
 538         FREE(dentry->file_name);
 539
 540         utf8_len = strlen(new_name);
 541
 542         dentry->file_name = utf8_to_utf16(new_name, utf8_len, &utf16_len);
 543
 544         if (!dentry->file_name)
 545                 return WIMLIB_ERR_NOMEM;
 546
 547         FREE(dentry->file_name_utf8);
 548         dentry->file_name_utf8 = MALLOC(utf8_len + 1);
 549         if (!dentry->file_name_utf8) {
 550                 FREE(dentry->file_name);
 551                 dentry->file_name = NULL;
 552                 return WIMLIB_ERR_NOMEM;
 553         }
 554
 555         dentry->file_name_len = utf16_len;
 556         dentry->file_name_utf8_len = utf8_len;
 557         memcpy(dentry->file_name_utf8, new_name, utf8_len + 1);
 558         recalculate_dentry_size(dentry);
 559         return 0;
 560 }
 561
 562 /* Parameters for calculate_dentry_statistics(). */
 563 struct image_statistics {
 564         struct lookup_table *lookup_table;
 565         u64 *dir_count;
 566         u64 *file_count;
 567         u64 *total_bytes;
 568         u64 *hard_link_bytes;
 569 };
 570
 571 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
 572 {
 573         struct image_statistics *stats;
 574         struct lookup_table_entry *lte;
 575
 576         stats = arg;
 577         lte = lookup_resource(stats->lookup_table, dentry->hash);
 578
 579         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
 580                 ++*stats->dir_count;
 581         else
 582                 ++*stats->file_count;
 583
 584         if (lte) {
 585                 u64 size = lte->resource_entry.original_size;
 586                 *stats->total_bytes += size;
 587                 if (++lte->out_refcnt == 1)
 588                         *stats->hard_link_bytes += size;
 589         }
 590         return 0;
 591 }
 592
 593 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
 594                                    u64 *dir_count_ret, u64 *file_count_ret,
 595                                    u64 *total_bytes_ret,
 596                                    u64 *hard_link_bytes_ret)
 597 {
 598         struct image_statistics stats;
 599         *dir_count_ret         = 0;
 600         *file_count_ret        = 0;
 601         *total_bytes_ret       = 0;
 602         *hard_link_bytes_ret   = 0;
 603         stats.lookup_table     = table;
 604         stats.dir_count       = dir_count_ret;
 605         stats.file_count      = file_count_ret;
 606         stats.total_bytes     = total_bytes_ret;
 607         stats.hard_link_bytes = hard_link_bytes_ret;
 608         for_lookup_table_entry(table, zero_out_refcnts, NULL);
 609         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
 610 }
 611
 612 /*
 613  * Reads a directory entry from the metadata resource.
 614  */
 615 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
 616                 u64 offset, struct dentry *dentry)
 617 {
 618         const u8 *p;
 619         u64 calculated_size;
 620         char *file_name;
 621         char *file_name_utf8;
 622         char *short_name;
 623         u16 short_name_len;
 624         u16 file_name_len;
 625         size_t file_name_utf8_len;
 626
 627         dentry_common_init(dentry);
 628
 629         /*Make sure the dentry really fits into the metadata resource.*/
 630         if (offset + 8 > metadata_resource_len) {
 631                 ERROR("Directory entry starting at %"PRIu64" ends past the "
 632                       "end of the metadata resource (size %"PRIu64")",
 633                       offset, metadata_resource_len);
 634                 return WIMLIB_ERR_INVALID_DENTRY;
 635         }
 636
 637         /* Before reading the whole entry, we need to read just the length.
 638          * This is because an entry of length 8 (that is, just the length field)
 639          * terminates the list of sibling directory entries. */
 640
 641         p = get_u64(&metadata_resource[offset], &dentry->length);
 642
 643         /* A zero length field (really a length of 8, since that's how big the
 644          * directory entry is...) indicates that this is the end of directory
 645          * dentry.  We do not read it into memory as an actual dentry, so just
 646          * return true in that case. */
 647         if (dentry->length == 0)
 648                 return 0;
 649
 650         if (offset + dentry->length >= metadata_resource_len) {
 651                 ERROR("Directory entry at offset %"PRIu64" and with size "
 652                       "%"PRIu64" ends past the end of the metadata resource "
 653                       "(size %"PRIu64")",
 654                       offset, dentry->length, metadata_resource_len);
 655                 return WIMLIB_ERR_INVALID_DENTRY;
 656         }
 657
 658         /* If it is a recognized length, read the rest of the directory entry.
 659          * Note: The root directory entry has no name, and its length does not
 660          * include the short name length field.  */
 661         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
 662                 ERROR("Directory entry has invalid length of %"PRIu64" bytes",
 663                       dentry->length);
 664                 return WIMLIB_ERR_INVALID_DENTRY;
 665         }
 666
 667         p = get_u32(p, &dentry->attributes);
 668 #ifdef ENABLE_SECURITY_DATA
 669         p = get_u32(p, (u32*)&dentry->security_id);
 670 #else
 671         p += sizeof(u32);
 672 #endif
 673         p = get_u64(p, &dentry->subdir_offset);
 674
 675         /* 2 unused fields */
 676         p += 2 * sizeof(u64);
 677
 678         p = get_u64(p, &dentry->creation_time);
 679         p = get_u64(p, &dentry->last_access_time);
 680         p = get_u64(p, &dentry->last_write_time);
 681
 682         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
 683
 684         /* Currently ignoring reparse_tag. */
 685         p += sizeof(u32);
 686
 687         /* The reparse_reserved field does not actually exist. */
 688
 689         p = get_u64(p, &dentry->hard_link);
 690
 691         /* Currently ignoring streams. */
 692         p += sizeof(u16);
 693
 694         p = get_u16(p, &short_name_len);
 695         p = get_u16(p, &file_name_len);
 696
 697         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
 698                           short_name_len;
 699
 700         if (dentry->length < calculated_size) {
 701                 ERROR("Unexpected end of directory entry! (Expected "
 702                       "%"PRIu64" bytes, got %"PRIu64" bytes. "
 703                       "short_name_len = %hu, file_name_len = %hu)",
 704                       calculated_size, dentry->length,
 705                       short_name_len, file_name_len);
 706                 return WIMLIB_ERR_INVALID_DENTRY;
 707         }
 708
 709         /* Read the filename. */
 710         file_name = MALLOC(file_name_len);
 711         if (!file_name) {
 712                 ERROR("Failed to allocate %hu bytes for dentry file name",
 713                       file_name_len);
 714                 return WIMLIB_ERR_NOMEM;
 715         }
 716         p = get_bytes(p, file_name_len, file_name);
 717
 718         /* Convert filename to UTF-8. */
 719         file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
 720                                        &file_name_utf8_len);
 721
 722         if (!file_name_utf8) {
 723                 ERROR("Failed to allocate memory to convert UTF-16 "
 724                       "filename (%hu bytes) to UTF-8", file_name_len);
 725                 goto out_free_file_name;
 726         }
 727
 728         /* Undocumented padding between file name and short name.  This probably
 729          * is supposed to be a terminating null character. */
 730         p += 2;
 731
 732         /* Read the short filename. */
 733         short_name = MALLOC(short_name_len);
 734         if (!short_name) {
 735                 ERROR("Failed to allocate %hu bytes for short filename",
 736                       short_name_len);
 737                 goto out_free_file_name_utf8;
 738         }
 739
 740         get_bytes(p, short_name_len, short_name);
 741
 742         dentry->file_name          = file_name;
 743         dentry->file_name_utf8     = file_name_utf8;
 744         dentry->short_name         = short_name;
 745         dentry->file_name_len      = file_name_len;
 746         dentry->file_name_utf8_len = file_name_utf8_len;
 747         dentry->short_name_len     = short_name_len;
 748         return 0;
 749 out_free_file_name_utf8:
 750         FREE(dentry->file_name_utf8);
 751 out_free_file_name:
 752         FREE(dentry->file_name);
 753         return WIMLIB_ERR_NOMEM;
 754 }
 755
 756 /*
 757  * Writes a dentry to an output buffer.
 758  *
 759  * @dentry:  The dentry structure.
 760  * @p:       The memory location to write the data to.
 761  * @return:  True on success, false on failure.
 762  */
 763 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
 764 {
 765         u8 *orig_p = p;
 766         memset(p, 0, dentry->length);
 767         p = put_u64(p, dentry->length);
 768         p = put_u32(p, dentry->attributes);
 769 #ifdef ENABLE_SECURITY_DATA
 770         p = put_u32(p, dentry->security_id);
 771 #else
 772         p = put_u32(p, (u32)(-1));
 773 #endif
 774         p = put_u64(p, dentry->subdir_offset);
 775         p = put_u64(p, 0); /* unused1 */
 776         p = put_u64(p, 0); /* unused2 */
 777         p = put_u64(p, dentry->creation_time);
 778         p = put_u64(p, dentry->last_access_time);
 779         p = put_u64(p, dentry->last_write_time);
 780         if (!is_empty_file_hash(dentry->hash))
 781                 memcpy(p, dentry->hash, WIM_HASH_SIZE);
 782         else
 783                 DEBUG("zero hash for %s\n", dentry->file_name_utf8);
 784         p += WIM_HASH_SIZE;
 785         p = put_u32(p, 0); /* reparse_tag */
 786         p = put_u64(p, dentry->hard_link);
 787         p = put_u16(p, 0); /*streams */
 788         p = put_u16(p, dentry->short_name_len);
 789         p = put_u16(p, dentry->file_name_len);
 790         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
 791         p = put_u16(p, 0); /* filename padding, 2 bytes. */
 792         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
 793         return orig_p + dentry->length;
 794 }
 795
 796 /* Recursive function that writes a dentry tree rooted at @tree, not including
 797  * @tree itself, which has already been written, except in the case of the root
 798  * dentry, which is written right away, along with an end-of-directory entry. */
 799 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
 800 {
 801         const struct dentry *child;
 802
 803         if (dentry_is_root(tree)) {
 804                 p = write_dentry(tree, p);
 805
 806                 /* write end of directory entry */
 807                 p = put_u64(p, 0);
 808         } else {
 809                 /* Nothing to do for a regular file. */
 810                 if (dentry_is_regular_file(tree))
 811                         return p;
 812         }
 813
 814         /* Write child dentries and end-of-directory entry. */
 815         child = tree->children;
 816         if (child) {
 817                 do {
 818                         p = write_dentry(child, p);
 819                         child = child->next;
 820                 } while (child != tree->children);
 821         }
 822
 823         /* write end of directory entry */
 824         p = put_u64(p, 0);
 825
 826         /* Recurse on children. */
 827         if (child) {
 828                 do {
 829                         p = write_dentry_tree(child, p);
 830                         child = child->next;
 831                 } while (child != tree->children);
 832         }
 833         return p;
 834 }
 835
 836 /* Reads the children of a dentry, and all their children, ..., etc. from the
 837  * metadata resource and into the dentry tree.
 838  *
 839  * @metadata_resource:  An array that contains the uncompressed metadata
 840  *                      resource for the WIM file.
 841  * @metadata_resource_len:      The length of @metadata_resource.
 842  * @dentry:     A pointer to a struct dentry that is the root of the directory
 843  *              tree and has already been read from the metadata resource.  It
 844  *              does not need to be the real root because this procedure is
 845  *              called recursively.
 846  *
 847  * @return:     Zero on success, nonzero on failure.
 848  */
 849 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 850                      struct dentry *dentry)
 851 {
 852         u64 cur_offset = dentry->subdir_offset;
 853         struct dentry *prev_child = NULL;
 854         struct dentry *first_child = NULL;
 855         struct dentry *child;
 856         struct dentry cur_child;
 857         int ret;
 858
 859         /* If @dentry is a regular file, nothing more needs to be done for this
 860          * branch. */
 861         if (cur_offset == 0)
 862                 return 0;
 863
 864         /* Find and read all the children of @dentry. */
 865         while (1) {
 866
 867                 /* Read next child of @dentry into @cur_child. */
 868                 ret = read_dentry(metadata_resource, metadata_resource_len,
 869                                   cur_offset, &cur_child);
 870                 if (ret != 0)
 871                         break;
 872
 873                 /* Check for end of directory. */
 874                 if (cur_child.length == 0) {
 875                         ret = 0;
 876                         break;
 877                 }
 878
 879                 /* Not end of directory.  Allocate this child permanently and
 880                  * link it to the parent and previous child. */
 881                 child = MALLOC(sizeof(struct dentry));
 882                 if (!child) {
 883                         ERROR("Failed to allocate %zu bytes for new dentry",
 884                               sizeof(struct dentry));
 885                         ret = WIMLIB_ERR_NOMEM;
 886                         break;
 887                 }
 888                 memcpy(child, &cur_child, sizeof(struct dentry));
 889
 890                 if (prev_child) {
 891                         prev_child->next = child;
 892                         child->prev = prev_child;
 893                 } else {
 894                         first_child = child;
 895                 }
 896
 897                 child->parent = dentry;
 898                 prev_child = child;
 899
 900                 /* If there are children of this child, call this procedure
 901                  * recursively. */
 902                 if (child->subdir_offset != 0) {
 903                         ret = read_dentry_tree(metadata_resource,
 904                                                metadata_resource_len, child);
 905                         if (ret != 0)
 906                                 break;
 907                 }
 908
 909                 /* Advance to the offset of the next child. */
 910                 cur_offset += child->length;
 911         }
 912
 913         /* Link last child to first one, and set parent's
 914          * children pointer to the first child.  */
 915         if (prev_child) {
 916                 prev_child->next = first_child;
 917                 first_child->prev = prev_child;
 918         }
 919         dentry->children = first_child;
 920         return ret;
 921 }