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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 <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         int parent_len;
 152         int len;
 153         char *parent_full_path;
 154         char *full_path;
 155
 156         FREE(dentry->full_path_utf8);
 157
 158         if (dentry_is_root(dentry)) {
 159                 dentry->full_path_utf8 = MALLOC(2);
 160                 if (!dentry->full_path_utf8) {
 161                         ERROR("Out of memory!\n");
 162                         return WIMLIB_ERR_NOMEM;
 163                 }
 164
 165                 dentry->full_path_utf8[0] = '/';
 166                 dentry->full_path_utf8[1] = '\0';
 167                 dentry->full_path_utf8_len = 1;
 168                 return 0;
 169         }
 170
 171         if (dentry_is_root(dentry->parent)) {
 172                 parent_len = 0;
 173                 parent_full_path = "";
 174         } else {
 175                 parent_len = dentry->parent->full_path_utf8_len;
 176                 parent_full_path = dentry->parent->full_path_utf8;
 177         }
 178
 179         len = parent_len + 1 + dentry->file_name_utf8_len;
 180         full_path = MALLOC(len + 1);
 181         if (!full_path) {
 182                 ERROR("Out of memory!\n");
 183                 return WIMLIB_ERR_NOMEM;
 184         }
 185
 186         memcpy(full_path, parent_full_path, parent_len);
 187         full_path[parent_len] = '/';
 188         memcpy(full_path + parent_len + 1, dentry->file_name_utf8,
 189                                 dentry->file_name_utf8_len);
 190         full_path[len] = '\0';
 191         dentry->full_path_utf8 = full_path;
 192         dentry->full_path_utf8_len = len;
 193         return 0;
 194 }
 195
 196 /*
 197  * Recursively calculates the subdir offsets for a directory tree.
 198  *
 199  * @dentry:  The root of the directory tree.
 200  * @subdir_offset_p:  The current subdirectory offset; i.e., the subdirectory
 201  *      offset for @dentry.
 202  */
 203 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
 204 {
 205         struct dentry *child;
 206
 207         child = dentry->children;
 208         dentry->subdir_offset = *subdir_offset_p;
 209         if (child) {
 210
 211                 /* Advance the subdir offset by the amount of space the children
 212                  * of this dentry take up. */
 213                 do {
 214                         *subdir_offset_p += child->length;
 215                         child = child->next;
 216                 } while (child != dentry->children);
 217
 218                 /* End-of-directory dentry on disk. */
 219                 *subdir_offset_p += 8;
 220
 221                 /* Recursively call calculate_subdir_offsets() on all the
 222                  * children. */
 223                 do {
 224                         calculate_subdir_offsets(child, subdir_offset_p);
 225                         child = child->next;
 226                 } while (child != dentry->children);
 227         } else {
 228                 /* On disk, childless directories have a valid subdir_offset
 229                  * that points to an 8-byte end-of-directory dentry.  Regular
 230                  * files have a subdir_offset of 0. */
 231                 if (dentry_is_directory(dentry))
 232                         *subdir_offset_p += 8;
 233                 else
 234                         dentry->subdir_offset = 0;
 235         }
 236 }
 237
 238
 239 /* Returns the child of @dentry that has the file name @name.
 240  * Returns NULL if no child has the name. */
 241 struct dentry *get_dentry_child_with_name(const struct dentry *dentry,
 242                                                         const char *name)
 243 {
 244         struct dentry *child;
 245         size_t name_len;
 246
 247         child = dentry->children;
 248         if (child) {
 249                 name_len = strlen(name);
 250                 do {
 251                         if (dentry_has_name(child, name, name_len))
 252                                 return child;
 253                         child = child->next;
 254                 } while (child != dentry->children);
 255         }
 256         return NULL;
 257 }
 258
 259 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
 260  * @cur_dir.  Returns NULL if no dentry having the path is found. */
 261 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir, const char *path)
 262 {
 263         struct dentry *child;
 264         size_t base_len;
 265         const char *new_path;
 266
 267         if (*path == '\0')
 268                 return cur_dir;
 269
 270         child = cur_dir->children;
 271         if (child) {
 272                 new_path = path_next_part(path, &base_len);
 273                 do {
 274                         if (dentry_has_name(child, path, base_len))
 275                                 return get_dentry_relative_path(child, new_path);
 276                         child = child->next;
 277                 } while (child != cur_dir->children);
 278         }
 279         return NULL;
 280 }
 281
 282 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
 283  * such dentry. */
 284 struct dentry *get_dentry(WIMStruct *w, const char *path)
 285 {
 286         struct dentry *root = wim_root_dentry(w);
 287         while (*path == '/')
 288                 path++;
 289         return get_dentry_relative_path(root, path);
 290 }
 291
 292 /* Returns the parent directory for the @path. */
 293 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
 294 {
 295         size_t path_len = strlen(path);
 296         char buf[path_len + 1];
 297
 298         memcpy(buf, path, path_len + 1);
 299
 300         to_parent_name(buf, path_len);
 301
 302         return get_dentry(w, buf);
 303 }
 304
 305 /* Prints the full path of a dentry. */
 306 int print_dentry_full_path(struct dentry *dentry, void *ignore)
 307 {
 308         if (dentry->full_path_utf8)
 309                 puts(dentry->full_path_utf8);
 310         return 0;
 311 }
 312
 313 /* Prints a directory entry.  @lookup_table is a pointer to the lookup table, or
 314  * NULL if the resource entry for the dentry is not to be printed. */
 315 int print_dentry(struct dentry *dentry, void *lookup_table)
 316 {
 317         struct lookup_table_entry *lte;
 318         printf("[DENTRY]\n");
 319         printf("Length            = %"PRIu64"\n", dentry->length);
 320         printf("Attributes        = 0x%x\n", dentry->attributes);
 321 #ifdef ENABLE_SECURITY_DATA
 322         printf("Security ID       = %d\n", dentry->security_id);
 323 #endif
 324         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
 325         /*printf("Unused1           = %"PRIu64"\n", dentry->unused1);*/
 326         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
 327         printf("Creation Time     = %"PRIu64"\n", dentry->creation_time);
 328         printf("Last Access Time  = %"PRIu64"\n", dentry->last_access_time);
 329         printf("Last Write Time   = %"PRIu64"\n", dentry->last_write_time);
 330         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
 331         printf("Hash              = ");
 332         print_hash(dentry->hash);
 333         putchar('\n');
 334         /*printf("Reparse Tag       = %u\n", dentry->reparse_tag);*/
 335         printf("Hard Link Group   = %"PRIu64"\n", dentry->hard_link);
 336         /*printf("Number of Streams = %hu\n", dentry->streams);*/
 337         printf("Filename          = \"");
 338         print_string(dentry->file_name, dentry->file_name_len);
 339         puts("\"");
 340         printf("Filename Length   = %hu\n", dentry->file_name_len);
 341         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
 342         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
 343         printf("Short Name        = \"");
 344         print_string(dentry->short_name, dentry->short_name_len);
 345         puts("\"");
 346         printf("Short Name Length = %hu\n", dentry->short_name_len);
 347         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
 348         if (lookup_table) {
 349                 lte = lookup_resource(lookup_table, dentry->hash);
 350                 if (lte)
 351                         print_lookup_table_entry(lte, NULL);
 352                 else
 353                         putchar('\n');
 354         } else {
 355                 putchar('\n');
 356         }
 357         return 0;
 358 }
 359
 360 static inline void dentry_common_init(struct dentry *dentry)
 361 {
 362         memset(dentry, 0, sizeof(struct dentry));
 363         dentry->refcnt = 1;
 364 #ifdef ENABLE_SECURITY_DATA
 365         dentry->security_id = -1;
 366 #endif
 367 }
 368
 369 /*
 370  * Creates an unlinked directory entry.
 371  *
 372  * @name:    The base name of the new dentry.
 373  * @return:  A pointer to the new dentry, or NULL if out of memory.
 374  */
 375 struct dentry *new_dentry(const char *name)
 376 {
 377         struct dentry *dentry;
 378
 379         dentry = MALLOC(sizeof(struct dentry));
 380         if (!dentry)
 381                 return NULL;
 382
 383         dentry_common_init(dentry);
 384         if (change_dentry_name(dentry, name) != 0) {
 385                 FREE(dentry);
 386                 return NULL;
 387         }
 388
 389         dentry_update_all_timestamps(dentry);
 390         dentry->next   = dentry;
 391         dentry->prev   = dentry;
 392         dentry->parent = dentry;
 393         return dentry;
 394 }
 395
 396
 397 void free_dentry(struct dentry *dentry)
 398 {
 399         FREE(dentry->file_name);
 400         FREE(dentry->file_name_utf8);
 401         FREE(dentry->short_name);
 402         FREE(dentry->full_path_utf8);
 403         FREE(dentry);
 404 }
 405
 406 /* Arguments for do_free_dentry(). */
 407 struct free_dentry_args {
 408         struct lookup_table *lookup_table;
 409         bool decrement_refcnt;
 410 };
 411
 412 /*
 413  * This function is passed as an argument to for_dentry_in_tree_depth() in order
 414  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
 415  */
 416 static int do_free_dentry(struct dentry *dentry, void *__args)
 417 {
 418         struct free_dentry_args *args = (struct free_dentry_args*)__args;
 419
 420         if (args->decrement_refcnt && !dentry_is_directory(dentry)) {
 421                 lookup_table_decrement_refcnt(args->lookup_table,
 422                                               dentry->hash);
 423         }
 424
 425         wimlib_assert(dentry->refcnt >= 1);
 426         if (--dentry->refcnt == 0)
 427                 free_dentry(dentry);
 428         return 0;
 429 }
 430
 431 /*
 432  * Unlinks and frees a dentry tree.
 433  *
 434  * @root:               The root of the tree.
 435  * @lookup_table:       The lookup table for dentries.
 436  * @decrement_refcnt:   True if the dentries in the tree are to have their
 437  *                      reference counts in the lookup table decremented.
 438  */
 439 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table,
 440                       bool decrement_refcnt)
 441 {
 442         if (!root || !root->parent)
 443                 return;
 444
 445         struct free_dentry_args args;
 446         args.lookup_table        = lookup_table;
 447         args.decrement_refcnt    = decrement_refcnt;
 448         for_dentry_in_tree_depth(root, do_free_dentry, &args);
 449 }
 450
 451 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
 452 {
 453         dentry->refcnt++;
 454         return 0;
 455 }
 456
 457 /*
 458  * Links a dentry into the directory tree.
 459  *
 460  * @dentry: The dentry to link.
 461  * @parent: The dentry that will be the parent of @dentry.
 462  */
 463 void link_dentry(struct dentry *dentry, struct dentry *parent)
 464 {
 465         dentry->parent = parent;
 466         if (parent->children) {
 467                 /* Not an only child; link to siblings. */
 468                 dentry->next = parent->children;
 469                 dentry->prev = parent->children->prev;
 470                 dentry->next->prev = dentry;
 471                 dentry->prev->next = dentry;
 472         } else {
 473                 /* Only child; link to parent. */
 474                 parent->children = dentry;
 475                 dentry->next = dentry;
 476                 dentry->prev = dentry;
 477         }
 478 }
 479
 480 /* Unlink a dentry from the directory tree. */
 481 void unlink_dentry(struct dentry *dentry)
 482 {
 483         if (dentry_is_root(dentry))
 484                 return;
 485         if (dentry_is_only_child(dentry)) {
 486                 dentry->parent->children = NULL;
 487         } else {
 488                 if (dentry_is_first_sibling(dentry))
 489                         dentry->parent->children = dentry->next;
 490                 dentry->next->prev = dentry->prev;
 491                 dentry->prev->next = dentry->next;
 492         }
 493 }
 494
 495
 496 /* Recalculates the length of @dentry based on its file name length and short
 497  * name length.  */
 498 static inline void recalculate_dentry_size(struct dentry *dentry)
 499 {
 500         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len +
 501                          2 + dentry->short_name_len;
 502         /* Must be multiple of 8. */
 503         dentry->length += (8 - dentry->length % 8) % 8;
 504 }
 505
 506 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
 507  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
 508  * full_path_utf8 fields.  Also recalculates its length. */
 509 int change_dentry_name(struct dentry *dentry, const char *new_name)
 510 {
 511         size_t utf8_len;
 512         size_t utf16_len;
 513
 514         FREE(dentry->file_name);
 515
 516         utf8_len = strlen(new_name);
 517
 518         dentry->file_name = utf8_to_utf16(new_name, utf8_len, &utf16_len);
 519
 520         if (!dentry->file_name)
 521                 return WIMLIB_ERR_NOMEM;
 522
 523         FREE(dentry->file_name_utf8);
 524         dentry->file_name_utf8 = MALLOC(utf8_len + 1);
 525         if (!dentry->file_name_utf8) {
 526                 FREE(dentry->file_name);
 527                 dentry->file_name = NULL;
 528                 return WIMLIB_ERR_NOMEM;
 529         }
 530
 531         dentry->file_name_len = utf16_len;
 532         dentry->file_name_utf8_len = utf8_len;
 533         memcpy(dentry->file_name_utf8, new_name, utf8_len + 1);
 534         recalculate_dentry_size(dentry);
 535         return 0;
 536 }
 537
 538 /* Parameters for calculate_dentry_statistics(). */
 539 struct image_statistics {
 540         struct lookup_table *lookup_table;
 541         u64 *dir_count;
 542         u64 *file_count;
 543         u64 *total_bytes;
 544         u64 *hard_link_bytes;
 545 };
 546
 547 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
 548 {
 549         struct image_statistics *stats;
 550         struct lookup_table_entry *lte;
 551
 552         stats = arg;
 553         lte = lookup_resource(stats->lookup_table, dentry->hash);
 554
 555         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
 556                 ++*stats->dir_count;
 557         else
 558                 ++*stats->file_count;
 559
 560         if (lte) {
 561                 u64 size = lte->resource_entry.original_size;
 562                 *stats->total_bytes += size;
 563                 if (++lte->out_refcnt == 1)
 564                         *stats->hard_link_bytes += size;
 565         }
 566         return 0;
 567 }
 568
 569 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
 570                                    u64 *dir_count_ret, u64 *file_count_ret,
 571                                    u64 *total_bytes_ret,
 572                                    u64 *hard_link_bytes_ret)
 573 {
 574         struct image_statistics stats;
 575         *dir_count_ret         = 0;
 576         *file_count_ret        = 0;
 577         *total_bytes_ret       = 0;
 578         *hard_link_bytes_ret   = 0;
 579         stats.lookup_table     = table;
 580         stats.dir_count       = dir_count_ret;
 581         stats.file_count      = file_count_ret;
 582         stats.total_bytes     = total_bytes_ret;
 583         stats.hard_link_bytes = hard_link_bytes_ret;
 584         for_lookup_table_entry(table, zero_out_refcnts, NULL);
 585         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
 586 }
 587
 588 /*
 589  * Reads a directory entry from the metadata resource.
 590  */
 591 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
 592                                         u64 offset, struct dentry *dentry)
 593 {
 594         const u8 *p;
 595         u64 calculated_size;
 596         char *file_name;
 597         char *file_name_utf8;
 598         char *short_name;
 599         u16 short_name_len;
 600         u16 file_name_len;
 601         size_t file_name_utf8_len;
 602
 603         dentry_common_init(dentry);
 604
 605         /*Make sure the dentry really fits into the metadata resource.*/
 606         if (offset + 8 > metadata_resource_len) {
 607                 ERROR("Directory entry starting at %"PRIu64" ends past the "
 608                         "end of the metadata resource (size %"PRIu64")!\n",
 609                         offset, metadata_resource_len);
 610                 return WIMLIB_ERR_INVALID_DENTRY;
 611         }
 612
 613         /* Before reading the whole entry, we need to read just the length.
 614          * This is because an entry of length 8 (that is, just the length field)
 615          * terminates the list of sibling directory entries. */
 616
 617         p = get_u64(&metadata_resource[offset], &dentry->length);
 618
 619         /* A zero length field (really a length of 8, since that's how big the
 620          * directory entry is...) indicates that this is the end of directory
 621          * dentry.  We do not read it into memory as an actual dentry, so just
 622          * return true in that case. */
 623         if (dentry->length == 0)
 624                 return 0;
 625
 626         if (offset + dentry->length >= metadata_resource_len) {
 627                 ERROR("Directory entry at offset %"PRIu64" and with size "
 628                                 "%"PRIu64" ends past the end of the metadata resource "
 629                                 "(size %"PRIu64")!\n", offset, dentry->length,
 630                                 metadata_resource_len);
 631                 return WIMLIB_ERR_INVALID_DENTRY;
 632         }
 633
 634         /* If it is a recognized length, read the rest of the directory entry.
 635          * Note: The root directory entry has no name, and its length does not
 636          * include the short name length field.  */
 637         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
 638                 ERROR("Directory entry has invalid length of "
 639                                 "%"PRIu64" bytes\n", dentry->length);
 640                 return WIMLIB_ERR_INVALID_DENTRY;
 641         }
 642
 643         p = get_u32(p, &dentry->attributes);
 644 #ifdef ENABLE_SECURITY_DATA
 645         p = get_u32(p, &dentry->security_id);
 646 #else
 647         p += sizeof(u32);
 648 #endif
 649         p = get_u64(p, &dentry->subdir_offset);
 650
 651         /* 2 unused fields */
 652         p += 2 * sizeof(u64);
 653
 654         p = get_u64(p, &dentry->creation_time);
 655         p = get_u64(p, &dentry->last_access_time);
 656         p = get_u64(p, &dentry->last_write_time);
 657
 658         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
 659
 660         /* Currently ignoring reparse_tag. */
 661         p += sizeof(u32);
 662
 663         /* The reparse_reserved field does not actually exist. */
 664
 665         p = get_u64(p, &dentry->hard_link);
 666
 667         /* Currently ignoring streams. */
 668         p += sizeof(u16);
 669
 670         p = get_u16(p, &short_name_len);
 671         p = get_u16(p, &file_name_len);
 672
 673         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
 674                           short_name_len;
 675
 676         if (dentry->length < calculated_size) {
 677                 ERROR("Unexpected end of directory entry! (Expected "
 678                                 "%"PRIu64" bytes, got %"PRIu64" bytes. "
 679                                 "short_name_len = %hu, file_name_len = %hu)\n",
 680                                 calculated_size, dentry->length,
 681                                 short_name_len, file_name_len);
 682                 return WIMLIB_ERR_INVALID_DENTRY;
 683         }
 684
 685         /* Read the filename. */
 686         file_name = MALLOC(file_name_len);
 687         if (!file_name) {
 688                 ERROR("Failed to allocate %hu bytes for dentry file name!\n",
 689                                 file_name_len);
 690                 return WIMLIB_ERR_NOMEM;
 691         }
 692         p = get_bytes(p, file_name_len, file_name);
 693
 694         /* Convert filename to UTF-8. */
 695         file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
 696                                        &file_name_utf8_len);
 697
 698         if (!file_name_utf8) {
 699                 ERROR("Failed to allocate memory to convert UTF16 "
 700                                 "filename (%hu bytes) to UTF8\n",
 701                                 file_name_len);
 702                 goto err_nomem2;
 703         }
 704
 705         /* Undocumented padding between file name and short name.  This probably
 706          * is supposed to be a terminating NULL character. */
 707         p += 2;
 708
 709         /* Read the short filename. */
 710         short_name = MALLOC(short_name_len);
 711         if (!short_name) {
 712                 ERROR("Failed to allocate %hu bytes for short filename\n",
 713                                 short_name_len);
 714                 goto err_nomem1;
 715         }
 716
 717         get_bytes(p, short_name_len, short_name);
 718
 719         dentry->file_name          = file_name;
 720         dentry->file_name_utf8     = file_name_utf8;
 721         dentry->short_name         = short_name;
 722         dentry->file_name_len      = file_name_len;
 723         dentry->file_name_utf8_len = file_name_utf8_len;
 724         dentry->short_name_len     = short_name_len;
 725         return 0;
 726 err_nomem1:
 727         FREE(dentry->file_name_utf8);
 728 err_nomem2:
 729         FREE(dentry->file_name);
 730         return WIMLIB_ERR_NOMEM;
 731 }
 732
 733 /*
 734  * Writes a dentry to an output buffer.
 735  *
 736  * @dentry:  The dentry structure.
 737  * @p:       The memory location to write the data to.
 738  * @return:  True on success, false on failure.
 739  */
 740 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
 741 {
 742         u8 *orig_p = p;
 743         memset(p, 0, dentry->length);
 744         p = put_u64(p, dentry->length);
 745         p = put_u32(p, dentry->attributes);
 746 #ifdef ENABLE_SECURITY_DATA
 747         p = put_u32(p, dentry->security_id);
 748 #else
 749         p = put_u32(p, (u32)(-1));
 750 #endif
 751         p = put_u64(p, dentry->subdir_offset);
 752         p = put_u64(p, 0); /* unused1 */
 753         p = put_u64(p, 0); /* unused2 */
 754         p = put_u64(p, dentry->creation_time);
 755         p = put_u64(p, dentry->last_access_time);
 756         p = put_u64(p, dentry->last_write_time);
 757         if (!is_empty_file_hash(dentry->hash))
 758                 memcpy(p, dentry->hash, WIM_HASH_SIZE);
 759         else
 760                 DEBUG("zero hash for %s\n", dentry->file_name_utf8);
 761         p += WIM_HASH_SIZE;
 762         p = put_u32(p, 0); /* reparse_tag */
 763         p = put_u64(p, dentry->hard_link);
 764         p = put_u16(p, 0); /*streams */
 765         p = put_u16(p, dentry->short_name_len);
 766         p = put_u16(p, dentry->file_name_len);
 767         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
 768         p = put_u16(p, 0); /* filename padding, 2 bytes. */
 769         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
 770         return orig_p + dentry->length;
 771 }
 772
 773 /* Recursive function that writes a dentry tree rooted at @tree, not including
 774  * @tree itself, which has already been written, except in the case of the root
 775  * dentry, which is written right away, along with an end-of-directory entry. */
 776 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
 777 {
 778         const struct dentry *child;
 779
 780         if (dentry_is_root(tree)) {
 781                 p = write_dentry(tree, p);
 782
 783                 /* write end of directory entry */
 784                 p = put_u64(p, 0);
 785         } else {
 786                 /* Nothing to do for a regular file. */
 787                 if (dentry_is_regular_file(tree))
 788                         return p;
 789         }
 790
 791         /* Write child dentries and end-of-directory entry. */
 792         child = tree->children;
 793         if (child) {
 794                 do {
 795                         p = write_dentry(child, p);
 796                         child = child->next;
 797                 } while (child != tree->children);
 798         }
 799
 800         /* write end of directory entry */
 801         p = put_u64(p, 0);
 802
 803         /* Recurse on children. */
 804         if (child) {
 805                 do {
 806                         p = write_dentry_tree(child, p);
 807                         child = child->next;
 808                 } while (child != tree->children);
 809         }
 810         return p;
 811 }
 812
 813 /* Reads the children of a dentry, and all their children, ..., etc. from the
 814  * metadata resource and into the dentry tree.
 815  *
 816  * @metadata_resource:  An array that contains the uncompressed metadata
 817  *                              resource for the WIM file.
 818  * @metadata_resource_len:      The length of @metadata_resource.
 819  * @dentry:     A pointer to a struct dentry that is the root of the directory tree
 820  *              and has already been read from the metadata resource.  It does not
 821  *              need to be the real root, because this procedure is called
 822  *              recursively.
 823  * @return:     True on success, false on failure.
 824  */
 825 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 826                      struct dentry *dentry)
 827 {
 828         u64 cur_offset = dentry->subdir_offset;
 829         struct dentry *prev_child = NULL;
 830         struct dentry *first_child = NULL;
 831         struct dentry *child;
 832         struct dentry cur_child;
 833         int ret;
 834
 835         /* If @dentry is a regular file, nothing more needs to be done for this
 836          * branch. */
 837         if (cur_offset == 0)
 838                 return 0;
 839
 840         /* Find and read all the children of @dentry. */
 841         while (1) {
 842
 843                 /* Read next child of @dentry into @cur_child. */
 844                 ret = read_dentry(metadata_resource, metadata_resource_len,
 845                                   cur_offset, &cur_child);
 846                 if (ret != 0)
 847                         break;
 848
 849                 /* Check for end of directory. */
 850                 if (cur_child.length == 0) {
 851                         ret = 0;
 852                         break;
 853                 }
 854
 855                 /* Not end of directory.  Allocate this child permanently and
 856                  * link it to the parent and previous child. */
 857                 child = MALLOC(sizeof(struct dentry));
 858                 if (!child) {
 859                         ERROR("Failed to allocate %zu bytes for new dentry!\n",
 860                                         sizeof(struct dentry));
 861                         ret = WIMLIB_ERR_NOMEM;
 862                         break;
 863                 }
 864                 memcpy(child, &cur_child, sizeof(struct dentry));
 865
 866                 if (prev_child) {
 867                         prev_child->next = child;
 868                         child->prev = prev_child;
 869                 } else {
 870                         first_child = child;
 871                 }
 872
 873                 child->parent = dentry;
 874                 prev_child = child;
 875
 876                 /* If there are children of this child, call this procedure
 877                  * recursively. */
 878                 if (child->subdir_offset != 0) {
 879                         ret = read_dentry_tree(metadata_resource,
 880                                                metadata_resource_len, child);
 881                         if (ret != 0)
 882                                 break;
 883                 }
 884
 885                 /* Advance to the offset of the next child. */
 886                 cur_offset += child->length;
 887         }
 888
 889         /* Link last child to first one, and set parent's
 890          * children pointer to the first child.  */
 891         if (prev_child) {
 892                 prev_child->next = first_child;
 893                 first_child->prev = prev_child;
 894         }
 895         dentry->children = first_child;
 896         return ret;
 897 }