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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         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         printf("Security ID       = %d\n", dentry->security_id);
 349         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
 350         /*printf("Unused1           = %"PRIu64"\n", dentry->unused1);*/
 351         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
 352         printf("Creation Time     = %"PRIu64"\n", dentry->creation_time);
 353         printf("Last Access Time  = %"PRIu64"\n", dentry->last_access_time);
 354         printf("Last Write Time   = %"PRIu64"\n", dentry->last_write_time);
 355         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
 356         printf("Hash              = ");
 357         print_hash(dentry->hash);
 358         putchar('\n');
 359         printf("Reparse Tag       = %u\n", dentry->reparse_tag);
 360         printf("Hard Link Group   = %"PRIu64"\n", dentry->hard_link);
 361         printf("Number of Alternate Data Streams = %hu\n", dentry->num_ads);
 362         printf("Filename          = \"");
 363         print_string(dentry->file_name, dentry->file_name_len);
 364         puts("\"");
 365         printf("Filename Length   = %hu\n", dentry->file_name_len);
 366         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
 367         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
 368         printf("Short Name        = \"");
 369         print_string(dentry->short_name, dentry->short_name_len);
 370         puts("\"");
 371         printf("Short Name Length = %hu\n", dentry->short_name_len);
 372         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
 373         if (lookup_table) {
 374                 lte = lookup_resource(lookup_table, dentry->hash);
 375                 if (lte)
 376                         print_lookup_table_entry(lte, NULL);
 377                 else
 378                         putchar('\n');
 379         } else {
 380                 putchar('\n');
 381         }
 382         return 0;
 383 }
 384
 385 static inline void dentry_common_init(struct dentry *dentry)
 386 {
 387         memset(dentry, 0, sizeof(struct dentry));
 388         dentry->refcnt = 1;
 389         dentry->security_id = -1;
 390 }
 391
 392 /*
 393  * Creates an unlinked directory entry.
 394  *
 395  * @name:    The base name of the new dentry.
 396  * @return:  A pointer to the new dentry, or NULL if out of memory.
 397  */
 398 struct dentry *new_dentry(const char *name)
 399 {
 400         struct dentry *dentry;
 401
 402         dentry = MALLOC(sizeof(struct dentry));
 403         if (!dentry)
 404                 return NULL;
 405
 406         dentry_common_init(dentry);
 407         if (change_dentry_name(dentry, name) != 0) {
 408                 FREE(dentry);
 409                 return NULL;
 410         }
 411
 412         dentry_update_all_timestamps(dentry);
 413         dentry->next   = dentry;
 414         dentry->prev   = dentry;
 415         dentry->parent = dentry;
 416         return dentry;
 417 }
 418
 419
 420 void free_dentry(struct dentry *dentry)
 421 {
 422         FREE(dentry->file_name);
 423         FREE(dentry->file_name_utf8);
 424         FREE(dentry->short_name);
 425         FREE(dentry->full_path_utf8);
 426         FREE(dentry);
 427 }
 428
 429 /* Arguments for do_free_dentry(). */
 430 struct free_dentry_args {
 431         struct lookup_table *lookup_table;
 432         bool lt_decrement_refcnt;
 433 };
 434
 435 /*
 436  * This function is passed as an argument to for_dentry_in_tree_depth() in order
 437  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
 438  */
 439 static int do_free_dentry(struct dentry *dentry, void *__args)
 440 {
 441         struct free_dentry_args *args = (struct free_dentry_args*)__args;
 442
 443         if (args->lt_decrement_refcnt && !dentry_is_directory(dentry)) {
 444                 lookup_table_decrement_refcnt(args->lookup_table,
 445                                               dentry->hash);
 446         }
 447
 448         wimlib_assert(dentry->refcnt >= 1);
 449         if (--dentry->refcnt == 0)
 450                 free_dentry(dentry);
 451         return 0;
 452 }
 453
 454 /*
 455  * Unlinks and frees a dentry tree.
 456  *
 457  * @root:               The root of the tree.
 458  * @lookup_table:       The lookup table for dentries.
 459  * @decrement_refcnt:   True if the dentries in the tree are to have their
 460  *                      reference counts in the lookup table decremented.
 461  */
 462 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table,
 463                       bool lt_decrement_refcnt)
 464 {
 465         if (!root || !root->parent)
 466                 return;
 467
 468         struct free_dentry_args args;
 469         args.lookup_table        = lookup_table;
 470         args.lt_decrement_refcnt = lt_decrement_refcnt;
 471         for_dentry_in_tree_depth(root, do_free_dentry, &args);
 472 }
 473
 474 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
 475 {
 476         dentry->refcnt++;
 477         return 0;
 478 }
 479
 480 /*
 481  * Links a dentry into the directory tree.
 482  *
 483  * @dentry: The dentry to link.
 484  * @parent: The dentry that will be the parent of @dentry.
 485  */
 486 void link_dentry(struct dentry *dentry, struct dentry *parent)
 487 {
 488         dentry->parent = parent;
 489         if (parent->children) {
 490                 /* Not an only child; link to siblings. */
 491                 dentry->next = parent->children;
 492                 dentry->prev = parent->children->prev;
 493                 dentry->next->prev = dentry;
 494                 dentry->prev->next = dentry;
 495         } else {
 496                 /* Only child; link to parent. */
 497                 parent->children = dentry;
 498                 dentry->next = dentry;
 499                 dentry->prev = dentry;
 500         }
 501 }
 502
 503 /* Unlink a dentry from the directory tree. */
 504 void unlink_dentry(struct dentry *dentry)
 505 {
 506         if (dentry_is_root(dentry))
 507                 return;
 508         if (dentry_is_only_child(dentry)) {
 509                 dentry->parent->children = NULL;
 510         } else {
 511                 if (dentry_is_first_sibling(dentry))
 512                         dentry->parent->children = dentry->next;
 513                 dentry->next->prev = dentry->prev;
 514                 dentry->prev->next = dentry->next;
 515         }
 516 }
 517
 518
 519 /* Recalculates the length of @dentry based on its file name length and short
 520  * name length.  */
 521 static inline void recalculate_dentry_size(struct dentry *dentry)
 522 {
 523         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len +
 524                          2 + dentry->short_name_len;
 525         for (u16 i = 0; i < dentry->num_ads; i++)
 526                 dentry->length += ads_entry_length(&dentry->ads_entries[i]);
 527         /* Must be multiple of 8. */
 528         dentry->length = (dentry->length + 7) & ~7;
 529 }
 530
 531 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
 532  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
 533  * full_path_utf8 fields.  Also recalculates its length. */
 534 int change_dentry_name(struct dentry *dentry, const char *new_name)
 535 {
 536         size_t utf8_len;
 537         size_t utf16_len;
 538
 539         FREE(dentry->file_name);
 540
 541         utf8_len = strlen(new_name);
 542
 543         dentry->file_name = utf8_to_utf16(new_name, utf8_len, &utf16_len);
 544
 545         if (!dentry->file_name)
 546                 return WIMLIB_ERR_NOMEM;
 547
 548         FREE(dentry->file_name_utf8);
 549         dentry->file_name_utf8 = MALLOC(utf8_len + 1);
 550         if (!dentry->file_name_utf8) {
 551                 FREE(dentry->file_name);
 552                 dentry->file_name = NULL;
 553                 return WIMLIB_ERR_NOMEM;
 554         }
 555
 556         dentry->file_name_len = utf16_len;
 557         dentry->file_name_utf8_len = utf8_len;
 558         memcpy(dentry->file_name_utf8, new_name, utf8_len + 1);
 559         recalculate_dentry_size(dentry);
 560         return 0;
 561 }
 562
 563 /* Parameters for calculate_dentry_statistics(). */
 564 struct image_statistics {
 565         struct lookup_table *lookup_table;
 566         u64 *dir_count;
 567         u64 *file_count;
 568         u64 *total_bytes;
 569         u64 *hard_link_bytes;
 570 };
 571
 572 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
 573 {
 574         struct image_statistics *stats;
 575         struct lookup_table_entry *lte;
 576
 577         stats = arg;
 578         lte = lookup_resource(stats->lookup_table, dentry->hash);
 579
 580         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
 581                 ++*stats->dir_count;
 582         else
 583                 ++*stats->file_count;
 584
 585         if (lte) {
 586                 u64 size = lte->resource_entry.original_size;
 587                 *stats->total_bytes += size;
 588                 if (++lte->out_refcnt == 1)
 589                         *stats->hard_link_bytes += size;
 590         }
 591         return 0;
 592 }
 593
 594 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
 595                                    u64 *dir_count_ret, u64 *file_count_ret,
 596                                    u64 *total_bytes_ret,
 597                                    u64 *hard_link_bytes_ret)
 598 {
 599         struct image_statistics stats;
 600         *dir_count_ret         = 0;
 601         *file_count_ret        = 0;
 602         *total_bytes_ret       = 0;
 603         *hard_link_bytes_ret   = 0;
 604         stats.lookup_table     = table;
 605         stats.dir_count       = dir_count_ret;
 606         stats.file_count      = file_count_ret;
 607         stats.total_bytes     = total_bytes_ret;
 608         stats.hard_link_bytes = hard_link_bytes_ret;
 609         for_lookup_table_entry(table, zero_out_refcnts, NULL);
 610         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
 611 }
 612
 613 static int read_ads_entries(const u8 *p, struct dentry *dentry,
 614                             unsigned remaining_size)
 615 {
 616         u16 num_ads = dentry->num_ads;
 617         struct ads_entry *ads_entries = CALLOC(num_ads, sizeof(struct ads_entry));
 618         int ret;
 619         if (!ads_entries) {
 620                 ERROR("Could not allocate memory for %u alternate data stream "
 621                       "entries", num_ads);
 622                 return WIMLIB_ERR_NOMEM;
 623         }
 624         for (u16 i = 0; i < num_ads; i++) {
 625                 struct ads_entry *cur_entry = &ads_entries[i];
 626                 u64 length;
 627                 size_t utf8_len;
 628                 /* Read the base stream entry, excluding the stream name. */
 629                 if (remaining_size < WIM_ADS_ENTRY_DISK_SIZE) {
 630                         ERROR("Stream entries go past end of directory entry");
 631                         ret = WIMLIB_ERR_INVALID_DENTRY;
 632                         goto out_free_ads_entries;
 633                 }
 634                 remaining_size -= WIM_ADS_ENTRY_DISK_SIZE;
 635
 636                 p = get_u64(p, &length); /* ADS entry length */
 637                 p += 8; /* Unused */
 638                 p = get_bytes(p, WIM_HASH_SIZE, (u8*)cur_entry->hash);
 639                 p = get_u16(p, &cur_entry->stream_name_len);
 640                 cur_entry->stream_name = NULL;
 641                 cur_entry->stream_name_utf8 = NULL;
 642
 643                 if (remaining_size < cur_entry->stream_name_len) {
 644                         ERROR("Stream entries go past end of directory entry");
 645                         ret = WIMLIB_ERR_INVALID_DENTRY;
 646                         goto out_free_ads_entries;
 647                 }
 648
 649                 cur_entry->stream_name = MALLOC(cur_entry->stream_name_len);
 650                 if (!cur_entry->stream_name) {
 651                         ret = WIMLIB_ERR_NOMEM;
 652                         goto out_free_ads_entries;
 653                 }
 654                 p = get_bytes(p, cur_entry->stream_name_len,
 655                               (u8*)cur_entry->stream_name);
 656                 cur_entry->stream_name_utf8 = utf16_to_utf8(cur_entry->stream_name,
 657                                                             cur_entry->stream_name_len,
 658                                                             &utf8_len);
 659                 cur_entry->stream_name_len_utf8 = utf8_len;
 660
 661                 if (!cur_entry->stream_name_utf8) {
 662                         ret = WIMLIB_ERR_NOMEM;
 663                         goto out_free_ads_entries;
 664                 }
 665         }
 666         dentry->ads_entries = ads_entries;
 667         return 0;
 668 out_free_ads_entries:
 669         for (u16 i = 0; i < num_ads; i++) {
 670                 FREE(ads_entries[i].stream_name);
 671                 FREE(ads_entries[i].stream_name_utf8);
 672         }
 673         FREE(ads_entries);
 674         return ret;
 675 }
 676
 677 /*
 678  * Reads a directory entry from the metadata resource.
 679  */
 680 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
 681                 u64 offset, struct dentry *dentry)
 682 {
 683         const u8 *p;
 684         u64 calculated_size;
 685         char *file_name;
 686         char *file_name_utf8;
 687         char *short_name;
 688         u16 short_name_len;
 689         u16 file_name_len;
 690         size_t file_name_utf8_len;
 691         int ret;
 692
 693         dentry_common_init(dentry);
 694
 695         /*Make sure the dentry really fits into the metadata resource.*/
 696         if (offset + 8 > metadata_resource_len) {
 697                 ERROR("Directory entry starting at %"PRIu64" ends past the "
 698                       "end of the metadata resource (size %"PRIu64")",
 699                       offset, metadata_resource_len);
 700                 return WIMLIB_ERR_INVALID_DENTRY;
 701         }
 702
 703         /* Before reading the whole entry, we need to read just the length.
 704          * This is because an entry of length 8 (that is, just the length field)
 705          * terminates the list of sibling directory entries. */
 706
 707         p = get_u64(&metadata_resource[offset], &dentry->length);
 708
 709         /* A zero length field (really a length of 8, since that's how big the
 710          * directory entry is...) indicates that this is the end of directory
 711          * dentry.  We do not read it into memory as an actual dentry, so just
 712          * return true in that case. */
 713         if (dentry->length == 0)
 714                 return 0;
 715
 716         if (offset + dentry->length >= metadata_resource_len) {
 717                 ERROR("Directory entry at offset %"PRIu64" and with size "
 718                       "%"PRIu64" ends past the end of the metadata resource "
 719                       "(size %"PRIu64")",
 720                       offset, dentry->length, metadata_resource_len);
 721                 return WIMLIB_ERR_INVALID_DENTRY;
 722         }
 723
 724         /* If it is a recognized length, read the rest of the directory entry.
 725          * Note: The root directory entry has no name, and its length does not
 726          * include the short name length field.  */
 727         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
 728                 ERROR("Directory entry has invalid length of %"PRIu64" bytes",
 729                       dentry->length);
 730                 return WIMLIB_ERR_INVALID_DENTRY;
 731         }
 732
 733         p = get_u32(p, &dentry->attributes);
 734         p = get_u32(p, (u32*)&dentry->security_id);
 735         p = get_u64(p, &dentry->subdir_offset);
 736
 737         /* 2 unused fields */
 738         p += 2 * sizeof(u64);
 739
 740         p = get_u64(p, &dentry->creation_time);
 741         p = get_u64(p, &dentry->last_access_time);
 742         p = get_u64(p, &dentry->last_write_time);
 743
 744         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
 745
 746         p = get_u32(p, &dentry->reparse_tag);
 747
 748         /* The reparse_reserved field does not actually exist. */
 749
 750         p = get_u64(p, &dentry->hard_link);
 751
 752         p = get_u16(p, &dentry->num_ads);
 753
 754         p = get_u16(p, &short_name_len);
 755         p = get_u16(p, &file_name_len);
 756
 757         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
 758                           short_name_len;
 759
 760         if (dentry->length < calculated_size) {
 761                 ERROR("Unexpected end of directory entry! (Expected "
 762                       "%"PRIu64" bytes, got %"PRIu64" bytes. "
 763                       "short_name_len = %hu, file_name_len = %hu)",
 764                       calculated_size, dentry->length,
 765                       short_name_len, file_name_len);
 766                 return WIMLIB_ERR_INVALID_DENTRY;
 767         }
 768
 769         /* Read the filename. */
 770         file_name = MALLOC(file_name_len);
 771         if (!file_name) {
 772                 ERROR("Failed to allocate %hu bytes for dentry file name",
 773                       file_name_len);
 774                 return WIMLIB_ERR_NOMEM;
 775         }
 776         p = get_bytes(p, file_name_len, file_name);
 777
 778         /* Convert filename to UTF-8. */
 779         file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
 780                                        &file_name_utf8_len);
 781
 782         if (!file_name_utf8) {
 783                 ERROR("Failed to allocate memory to convert UTF-16 "
 784                       "filename (%hu bytes) to UTF-8", file_name_len);
 785                 ret = WIMLIB_ERR_NOMEM;
 786                 goto out_free_file_name;
 787         }
 788
 789         /* Undocumented padding between file name and short name.  This probably
 790          * is supposed to be a terminating null character. */
 791         p += 2;
 792
 793         /* Read the short filename. */
 794         short_name = MALLOC(short_name_len);
 795         if (!short_name) {
 796                 ERROR("Failed to allocate %hu bytes for short filename",
 797                       short_name_len);
 798                 ret = WIMLIB_ERR_NOMEM;
 799                 goto out_free_file_name_utf8;
 800         }
 801
 802         get_bytes(p, short_name_len, short_name);
 803
 804         if (dentry->num_ads != 0) {
 805                 ret = read_ads_entries(p, dentry,
 806                                        dentry->length - calculated_size);
 807                 if (ret != 0)
 808                         goto out_free_short_name;
 809         }
 810
 811         dentry->file_name          = file_name;
 812         dentry->file_name_utf8     = file_name_utf8;
 813         dentry->short_name         = short_name;
 814         dentry->file_name_len      = file_name_len;
 815         dentry->file_name_utf8_len = file_name_utf8_len;
 816         dentry->short_name_len     = short_name_len;
 817         return 0;
 818 out_free_short_name:
 819         FREE(short_name);
 820 out_free_file_name_utf8:
 821         FREE(file_name_utf8);
 822 out_free_file_name:
 823         FREE(file_name);
 824         return ret;
 825 }
 826
 827 /*
 828  * Writes a dentry to an output buffer.
 829  *
 830  * @dentry:  The dentry structure.
 831  * @p:       The memory location to write the data to.
 832  * @return:  Pointer to the byte after the last byte we wrote as part of the
 833  *              dentry.
 834  */
 835 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
 836 {
 837         u8 *orig_p = p;
 838         memset(p, 0, dentry->length);
 839         p = put_u64(p, dentry->length);
 840         p = put_u32(p, dentry->attributes);
 841         p = put_u32(p, dentry->security_id);
 842         p = put_u64(p, dentry->subdir_offset);
 843         p = put_u64(p, 0); /* unused1 */
 844         p = put_u64(p, 0); /* unused2 */
 845         p = put_u64(p, dentry->creation_time);
 846         p = put_u64(p, dentry->last_access_time);
 847         p = put_u64(p, dentry->last_write_time);
 848         if (!is_empty_file_hash(dentry->hash))
 849                 memcpy(p, dentry->hash, WIM_HASH_SIZE);
 850         else
 851                 DEBUG("zero hash for %s\n", dentry->file_name_utf8);
 852         p += WIM_HASH_SIZE;
 853         p = put_u32(p, dentry->reparse_tag);
 854         p = put_u64(p, dentry->hard_link);
 855         p = put_u16(p, dentry->num_ads); /*streams */
 856         p = put_u16(p, dentry->short_name_len);
 857         p = put_u16(p, dentry->file_name_len);
 858         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
 859         p = put_u16(p, 0); /* filename padding, 2 bytes. */
 860         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
 861         for (u16 i = 0; i < dentry->num_ads; i++) {
 862                 p = put_u64(p, ads_entry_length(&dentry->ads_entries[i]));
 863                 p = put_u64(p, 0); /* Unused */
 864                 p = put_bytes(p, WIM_HASH_SIZE, dentry->ads_entries[i].hash);
 865                 p = put_u16(p, dentry->ads_entries[i].stream_name_len);
 866                 p = put_bytes(p, dentry->ads_entries[i].stream_name_len,
 867                                  (u8*)dentry->ads_entries[i].stream_name);
 868         }
 869         return orig_p + dentry->length;
 870 }
 871
 872 /* Recursive function that writes a dentry tree rooted at @tree, not including
 873  * @tree itself, which has already been written, except in the case of the root
 874  * dentry, which is written right away, along with an end-of-directory entry. */
 875 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
 876 {
 877         const struct dentry *child;
 878
 879         if (dentry_is_root(tree)) {
 880                 p = write_dentry(tree, p);
 881
 882                 /* write end of directory entry */
 883                 p = put_u64(p, 0);
 884         } else {
 885                 /* Nothing to do for a regular file. */
 886                 if (dentry_is_regular_file(tree))
 887                         return p;
 888         }
 889
 890         /* Write child dentries and end-of-directory entry. */
 891         child = tree->children;
 892         if (child) {
 893                 do {
 894                         p = write_dentry(child, p);
 895                         child = child->next;
 896                 } while (child != tree->children);
 897         }
 898
 899         /* write end of directory entry */
 900         p = put_u64(p, 0);
 901
 902         /* Recurse on children. */
 903         if (child) {
 904                 do {
 905                         p = write_dentry_tree(child, p);
 906                         child = child->next;
 907                 } while (child != tree->children);
 908         }
 909         return p;
 910 }
 911
 912 /* Reads the children of a dentry, and all their children, ..., etc. from the
 913  * metadata resource and into the dentry tree.
 914  *
 915  * @metadata_resource:  An array that contains the uncompressed metadata
 916  *                      resource for the WIM file.
 917  * @metadata_resource_len:      The length of @metadata_resource.
 918  * @dentry:     A pointer to a struct dentry that is the root of the directory
 919  *              tree and has already been read from the metadata resource.  It
 920  *              does not need to be the real root because this procedure is
 921  *              called recursively.
 922  *
 923  * @return:     Zero on success, nonzero on failure.
 924  */
 925 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
 926                      struct dentry *dentry)
 927 {
 928         u64 cur_offset = dentry->subdir_offset;
 929         struct dentry *prev_child = NULL;
 930         struct dentry *first_child = NULL;
 931         struct dentry *child;
 932         struct dentry cur_child;
 933         int ret;
 934
 935         /* If @dentry is a regular file, nothing more needs to be done for this
 936          * branch. */
 937         if (cur_offset == 0)
 938                 return 0;
 939
 940         /* Find and read all the children of @dentry. */
 941         while (1) {
 942
 943                 /* Read next child of @dentry into @cur_child. */
 944                 ret = read_dentry(metadata_resource, metadata_resource_len,
 945                                   cur_offset, &cur_child);
 946                 if (ret != 0)
 947                         break;
 948
 949                 /* Check for end of directory. */
 950                 if (cur_child.length == 0) {
 951                         ret = 0;
 952                         break;
 953                 }
 954
 955                 /* Not end of directory.  Allocate this child permanently and
 956                  * link it to the parent and previous child. */
 957                 child = MALLOC(sizeof(struct dentry));
 958                 if (!child) {
 959                         ERROR("Failed to allocate %zu bytes for new dentry",
 960                               sizeof(struct dentry));
 961                         ret = WIMLIB_ERR_NOMEM;
 962                         break;
 963                 }
 964                 memcpy(child, &cur_child, sizeof(struct dentry));
 965
 966                 if (prev_child) {
 967                         prev_child->next = child;
 968                         child->prev = prev_child;
 969                 } else {
 970                         first_child = child;
 971                 }
 972
 973                 child->parent = dentry;
 974                 prev_child = child;
 975
 976                 /* If there are children of this child, call this procedure
 977                  * recursively. */
 978                 if (child->subdir_offset != 0) {
 979                         ret = read_dentry_tree(metadata_resource,
 980                                                metadata_resource_len, child);
 981                         if (ret != 0)
 982                                 break;
 983                 }
 984
 985                 /* Advance to the offset of the next child. */
 986                 cur_offset += child->length;
 987         }
 988
 989         /* Link last child to first one, and set parent's
 990          * children pointer to the first child.  */
 991         if (prev_child) {
 992                 prev_child->next = first_child;
 993                 first_child->prev = prev_child;
 994         }
 995         dentry->children = first_child;
 996         return ret;
 997 }