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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 /* Real length of a dentry, including the alternate data stream entries, which
  43  * are not included in the dentry->length field... */
  44 u64 dentry_total_length(const struct dentry *dentry)
  45 {
  46         u64 length = dentry->length;
  47         if (dentry->num_ads) {
  48                 u16 i = 0;
  49                 do {
  50                         length += WIM_ADS_ENTRY_DISK_SIZE +
  51                                   dentry->ads_entries[i].stream_name_len;
  52                 } while (++i != dentry->num_ads);
  53                 /* If there are Alternate Stream Entries, we apparently need to
  54                  * round up to the NEXT 8-byte boundary, even if we are already
  55                  * aligned on one... */
  56                 length++;
  57         }
  58         /* Round to 8 byte boundary. */
  59         return (length + 7) & ~7;
  60 }
  61
  62 /* Transfers file attributes from a `stat' buffer to a struct dentry. */
  63 void stbuf_to_dentry(const struct stat *stbuf, struct dentry *dentry)
  64 {
  65         if (S_ISDIR(stbuf->st_mode))
  66                 dentry->attributes = FILE_ATTRIBUTE_DIRECTORY;
  67         else
  68                 dentry->attributes = FILE_ATTRIBUTE_NORMAL;
  69 }
  70
  71 /* Transfers file attributes from a struct dentry to a `stat' buffer. */
  72 void dentry_to_stbuf(const struct dentry *dentry, struct stat *stbuf,
  73                      const struct lookup_table *table)
  74 {
  75         struct lookup_table_entry *lte;
  76
  77         if (dentry_is_directory(dentry))
  78                 stbuf->st_mode = S_IFDIR | 0755;
  79         else
  80                 stbuf->st_mode = S_IFREG | 0644;
  81
  82         if (table)
  83                 lte = lookup_resource(table, dentry->hash);
  84         else
  85                 lte = NULL;
  86
  87         if (lte) {
  88                 stbuf->st_nlink = lte->refcnt;
  89                 stbuf->st_size = lte->resource_entry.original_size;
  90         } else {
  91                 stbuf->st_nlink = 1;
  92                 stbuf->st_size = 0;
  93         }
  94         stbuf->st_uid     = getuid();
  95         stbuf->st_gid     = getgid();
  96         stbuf->st_atime   = ms_timestamp_to_unix(dentry->last_access_time);
  97         stbuf->st_mtime   = ms_timestamp_to_unix(dentry->last_write_time);
  98         stbuf->st_ctime   = ms_timestamp_to_unix(dentry->creation_time);
  99         stbuf->st_blocks  = (stbuf->st_size + 511) / 512;
 100 }
 101
 102 /* Makes all timestamp fields for the dentry be the current time. */
 103 void dentry_update_all_timestamps(struct dentry *dentry)
 104 {
 105         u64 now = get_timestamp();
 106         dentry->creation_time    = now;
 107         dentry->last_access_time = now;
 108         dentry->last_write_time  = now;
 109 }
 110
 111 /*
 112  * Calls a function on all directory entries in a directory tree.  It is called
 113  * on a parent before its children.
 114  */
 115 int for_dentry_in_tree(struct dentry *root,
 116                        int (*visitor)(struct dentry*, void*), void *arg)
 117 {
 118         int ret;
 119         struct dentry *child;
 120
 121         ret = visitor(root, arg);
 122
 123         if (ret != 0)
 124                 return ret;
 125
 126         child = root->children;
 127
 128         if (!child)
 129                 return 0;
 130
 131         do {
 132                 ret = for_dentry_in_tree(child, visitor, arg);
 133                 if (ret != 0)
 134                         return ret;
 135                 child = child->next;
 136         } while (child != root->children);
 137         return 0;
 138 }
 139
 140 /*
 141  * Like for_dentry_in_tree(), but the visitor function is always called on a
 142  * dentry's children before on itself.
 143  */
 144 int for_dentry_in_tree_depth(struct dentry *root,
 145                              int (*visitor)(struct dentry*, void*), void *arg)
 146 {
 147         int ret;
 148         struct dentry *child;
 149         struct dentry *next;
 150
 151         child = root->children;
 152         if (child) {
 153                 do {
 154                         next = child->next;
 155                         ret = for_dentry_in_tree_depth(child, visitor, arg);
 156                         if (ret != 0)
 157                                 return ret;
 158                         child = next;
 159                 } while (child != root->children);
 160         }
 161         return visitor(root, arg);
 162 }
 163
 164 /*
 165  * Calculate the full path of @dentry, based on its parent's full path and on
 166  * its UTF-8 file name.
 167  */
 168 int calculate_dentry_full_path(struct dentry *dentry, void *ignore)
 169 {
 170         char *full_path;
 171         u32 full_path_len;
 172         if (dentry_is_root(dentry)) {
 173                 full_path = MALLOC(2);
 174                 if (!full_path)
 175                         goto oom;
 176                 full_path[0] = '/';
 177                 full_path[1] = '\0';
 178                 full_path_len = 1;
 179         } else {
 180                 char *parent_full_path;
 181                 u32 parent_full_path_len;
 182                 const struct dentry *parent = dentry->parent;
 183
 184                 if (dentry_is_root(parent)) {
 185                         parent_full_path = "";
 186                         parent_full_path_len = 0;
 187                 } else {
 188                         parent_full_path = parent->full_path_utf8;
 189                         parent_full_path_len = parent->full_path_utf8_len;
 190                 }
 191
 192                 full_path_len = parent_full_path_len + 1 +
 193                                 dentry->file_name_utf8_len;
 194                 full_path = MALLOC(full_path_len + 1);
 195                 if (!full_path)
 196                         goto oom;
 197
 198                 memcpy(full_path, parent_full_path, parent_full_path_len);
 199                 full_path[parent_full_path_len] = '/';
 200                 memcpy(full_path + parent_full_path_len + 1,
 201                        dentry->file_name_utf8,
 202                        dentry->file_name_utf8_len);
 203                 full_path[full_path_len] = '\0';
 204         }
 205         FREE(dentry->full_path_utf8);
 206         dentry->full_path_utf8 = full_path;
 207         dentry->full_path_utf8_len = full_path_len;
 208         return 0;
 209 oom:
 210         ERROR("Out of memory while calculating dentry full path");
 211         return WIMLIB_ERR_NOMEM;
 212 }
 213
 214 /*
 215  * Recursively calculates the subdir offsets for a directory tree.
 216  *
 217  * @dentry:  The root of the directory tree.
 218  * @subdir_offset_p:  The current subdirectory offset; i.e., the subdirectory
 219  *      offset for @dentry.
 220  */
 221 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
 222 {
 223         struct dentry *child;
 224
 225         child = dentry->children;
 226         dentry->subdir_offset = *subdir_offset_p;
 227         if (child) {
 228
 229                 /* Advance the subdir offset by the amount of space the children
 230                  * of this dentry take up. */
 231                 do {
 232                         *subdir_offset_p += dentry_total_length(child);
 233                         child = child->next;
 234                 } while (child != dentry->children);
 235
 236                 /* End-of-directory dentry on disk. */
 237                 *subdir_offset_p += 8;
 238
 239                 /* Recursively call calculate_subdir_offsets() on all the
 240                  * children. */
 241                 do {
 242                         calculate_subdir_offsets(child, subdir_offset_p);
 243                         child = child->next;
 244                 } while (child != dentry->children);
 245         } else {
 246                 /* On disk, childless directories have a valid subdir_offset
 247                  * that points to an 8-byte end-of-directory dentry.  Regular
 248                  * files have a subdir_offset of 0. */
 249                 if (dentry_is_directory(dentry))
 250                         *subdir_offset_p += 8;
 251                 else
 252                         dentry->subdir_offset = 0;
 253         }
 254 }
 255
 256
 257 /* Returns the child of @dentry that has the file name @name.
 258  * Returns NULL if no child has the name. */
 259 struct dentry *get_dentry_child_with_name(const struct dentry *dentry,
 260                                                         const char *name)
 261 {
 262         struct dentry *child;
 263         size_t name_len;
 264
 265         child = dentry->children;
 266         if (child) {
 267                 name_len = strlen(name);
 268                 do {
 269                         if (dentry_has_name(child, name, name_len))
 270                                 return child;
 271                         child = child->next;
 272                 } while (child != dentry->children);
 273         }
 274         return NULL;
 275 }
 276
 277 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
 278  * @cur_dir.  Returns NULL if no dentry having the path is found. */
 279 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir, const char *path)
 280 {
 281         struct dentry *child;
 282         size_t base_len;
 283         const char *new_path;
 284
 285         if (*path == '\0')
 286                 return cur_dir;
 287
 288         child = cur_dir->children;
 289         if (child) {
 290                 new_path = path_next_part(path, &base_len);
 291                 do {
 292                         if (dentry_has_name(child, path, base_len))
 293                                 return get_dentry_relative_path(child, new_path);
 294                         child = child->next;
 295                 } while (child != cur_dir->children);
 296         }
 297         return NULL;
 298 }
 299
 300 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
 301  * such dentry. */
 302 struct dentry *get_dentry(WIMStruct *w, const char *path)
 303 {
 304         struct dentry *root = wim_root_dentry(w);
 305         while (*path == '/')
 306                 path++;
 307         return get_dentry_relative_path(root, path);
 308 }
 309
 310 /* Returns the parent directory for the @path. */
 311 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
 312 {
 313         size_t path_len = strlen(path);
 314         char buf[path_len + 1];
 315
 316         memcpy(buf, path, path_len + 1);
 317
 318         to_parent_name(buf, path_len);
 319
 320         return get_dentry(w, buf);
 321 }
 322
 323 /* Prints the full path of a dentry. */
 324 int print_dentry_full_path(struct dentry *dentry, void *ignore)
 325 {
 326         if (dentry->full_path_utf8)
 327                 puts(dentry->full_path_utf8);
 328         return 0;
 329 }
 330
 331 struct file_attr_flag {
 332         u32 flag;
 333         const char *name;
 334 };
 335 struct file_attr_flag file_attr_flags[] = {
 336         {FILE_ATTRIBUTE_READONLY,               "READONLY"},
 337         {FILE_ATTRIBUTE_HIDDEN,         "HIDDEN"},
 338         {FILE_ATTRIBUTE_SYSTEM,         "SYSTEM"},
 339         {FILE_ATTRIBUTE_DIRECTORY,              "DIRECTORY"},
 340         {FILE_ATTRIBUTE_ARCHIVE,                "ARCHIVE"},
 341         {FILE_ATTRIBUTE_DEVICE,         "DEVICE"},
 342         {FILE_ATTRIBUTE_NORMAL,         "NORMAL"},
 343         {FILE_ATTRIBUTE_TEMPORARY,              "TEMPORARY"},
 344         {FILE_ATTRIBUTE_SPARSE_FILE,    "SPARSE_FILE"},
 345         {FILE_ATTRIBUTE_REPARSE_POINT,  "REPARSE_POINT"},
 346         {FILE_ATTRIBUTE_COMPRESSED,             "COMPRESSED"},
 347         {FILE_ATTRIBUTE_OFFLINE,                "OFFLINE"},
 348         {FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,"NOT_CONTENT_INDEXED"},
 349         {FILE_ATTRIBUTE_ENCRYPTED,              "ENCRYPTED"},
 350         {FILE_ATTRIBUTE_VIRTUAL,                "VIRTUAL"},
 351 };
 352
 353 /* Prints a directory entry.  @lookup_table is a pointer to the lookup table, or
 354  * NULL if the resource entry for the dentry is not to be printed. */
 355 int print_dentry(struct dentry *dentry, void *lookup_table)
 356 {
 357         struct lookup_table_entry *lte;
 358         unsigned i;
 359
 360         printf("[DENTRY]\n");
 361         printf("Length            = %"PRIu64"\n", dentry->length);
 362         printf("Attributes        = 0x%x\n", dentry->attributes);
 363         for (i = 0; i < ARRAY_LEN(file_attr_flags); i++)
 364                 if (file_attr_flags[i].flag & dentry->attributes)
 365                         printf("    FILE_ATTRIBUTE_%s is set\n",
 366                                 file_attr_flags[i].name);
 367         printf("Security ID       = %d\n", dentry->security_id);
 368         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
 369         /*printf("Unused1           = 0x%"PRIu64"\n", dentry->unused1);*/
 370         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
 371         printf("Creation Time     = %"PRIu64"\n", dentry->creation_time);
 372         printf("Last Access Time  = %"PRIu64"\n", dentry->last_access_time);
 373         printf("Last Write Time   = %"PRIu64"\n", dentry->last_write_time);
 374         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
 375         printf("Hash              = ");
 376         print_hash(dentry->hash);
 377         putchar('\n');
 378         printf("Reparse Tag       = 0x%"PRIx32"\n", dentry->reparse_tag);
 379         printf("Hard Link Group   = 0x%"PRIx64"\n", dentry->hard_link);
 380         printf("Number of Alternate Data Streams = %hu\n", dentry->num_ads);
 381         printf("Filename          = \"");
 382         print_string(dentry->file_name, dentry->file_name_len);
 383         puts("\"");
 384         printf("Filename Length   = %hu\n", dentry->file_name_len);
 385         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
 386         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
 387         printf("Short Name        = \"");
 388         print_string(dentry->short_name, dentry->short_name_len);
 389         puts("\"");
 390         printf("Short Name Length = %hu\n", dentry->short_name_len);
 391         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
 392         if (lookup_table) {
 393                 lte = lookup_resource(lookup_table, dentry->hash);
 394                 if (lte)
 395                         print_lookup_table_entry(lte, NULL);
 396                 else
 397                         putchar('\n');
 398         } else {
 399                 putchar('\n');
 400         }
 401         for (u16 i = 0; i < dentry->num_ads; i++) {
 402                 printf("[Alternate Stream Entry %u]\n", i);
 403                 printf("Name = \"%s\"\n", dentry->ads_entries[i].stream_name_utf8);
 404                 lte = lookup_resource(lookup_table, dentry->ads_entries[i].hash);
 405                 if (lte)
 406                         print_lookup_table_entry(lte, NULL);
 407                 else
 408                         putchar('\n');
 409         }
 410         return 0;
 411 }
 412
 413 static inline void dentry_common_init(struct dentry *dentry)
 414 {
 415         memset(dentry, 0, sizeof(struct dentry));
 416         dentry->refcnt = 1;
 417         dentry->security_id = -1;
 418 }
 419
 420 /*
 421  * Creates an unlinked directory entry.
 422  *
 423  * @name:    The base name of the new dentry.
 424  * @return:  A pointer to the new dentry, or NULL if out of memory.
 425  */
 426 struct dentry *new_dentry(const char *name)
 427 {
 428         struct dentry *dentry;
 429
 430         dentry = MALLOC(sizeof(struct dentry));
 431         if (!dentry)
 432                 return NULL;
 433
 434         dentry_common_init(dentry);
 435         if (change_dentry_name(dentry, name) != 0) {
 436                 FREE(dentry);
 437                 return NULL;
 438         }
 439
 440         dentry_update_all_timestamps(dentry);
 441         dentry->next   = dentry;
 442         dentry->prev   = dentry;
 443         dentry->parent = dentry;
 444         return dentry;
 445 }
 446
 447
 448 void free_dentry(struct dentry *dentry)
 449 {
 450         FREE(dentry->file_name);
 451         FREE(dentry->file_name_utf8);
 452         FREE(dentry->short_name);
 453         FREE(dentry->full_path_utf8);
 454         FREE(dentry);
 455 }
 456
 457 /* Arguments for do_free_dentry(). */
 458 struct free_dentry_args {
 459         struct lookup_table *lookup_table;
 460         bool lt_decrement_refcnt;
 461 };
 462
 463 /*
 464  * This function is passed as an argument to for_dentry_in_tree_depth() in order
 465  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
 466  */
 467 static int do_free_dentry(struct dentry *dentry, void *__args)
 468 {
 469         struct free_dentry_args *args = (struct free_dentry_args*)__args;
 470
 471         if (args->lt_decrement_refcnt && !dentry_is_directory(dentry)) {
 472                 lookup_table_decrement_refcnt(args->lookup_table,
 473                                               dentry->hash);
 474         }
 475
 476         wimlib_assert(dentry->refcnt >= 1);
 477         if (--dentry->refcnt == 0)
 478                 free_dentry(dentry);
 479         return 0;
 480 }
 481
 482 /*
 483  * Unlinks and frees a dentry tree.
 484  *
 485  * @root:               The root of the tree.
 486  * @lookup_table:       The lookup table for dentries.
 487  * @decrement_refcnt:   True if the dentries in the tree are to have their
 488  *                      reference counts in the lookup table decremented.
 489  */
 490 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table,
 491                       bool lt_decrement_refcnt)
 492 {
 493         if (!root || !root->parent)
 494                 return;
 495
 496         struct free_dentry_args args;
 497         args.lookup_table        = lookup_table;
 498         args.lt_decrement_refcnt = lt_decrement_refcnt;
 499         for_dentry_in_tree_depth(root, do_free_dentry, &args);
 500 }
 501
 502 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
 503 {
 504         dentry->refcnt++;
 505         return 0;
 506 }
 507
 508 /*
 509  * Links a dentry into the directory tree.
 510  *
 511  * @dentry: The dentry to link.
 512  * @parent: The dentry that will be the parent of @dentry.
 513  */
 514 void link_dentry(struct dentry *dentry, struct dentry *parent)
 515 {
 516         dentry->parent = parent;
 517         if (parent->children) {
 518                 /* Not an only child; link to siblings. */
 519                 dentry->next = parent->children;
 520                 dentry->prev = parent->children->prev;
 521                 dentry->next->prev = dentry;
 522                 dentry->prev->next = dentry;
 523         } else {
 524                 /* Only child; link to parent. */
 525                 parent->children = dentry;
 526                 dentry->next = dentry;
 527                 dentry->prev = dentry;
 528         }
 529 }
 530
 531 /* Unlink a dentry from the directory tree. */
 532 void unlink_dentry(struct dentry *dentry)
 533 {
 534         if (dentry_is_root(dentry))
 535                 return;
 536         if (dentry_is_only_child(dentry)) {
 537                 dentry->parent->children = NULL;
 538         } else {
 539                 if (dentry_is_first_sibling(dentry))
 540                         dentry->parent->children = dentry->next;
 541                 dentry->next->prev = dentry->prev;
 542                 dentry->prev->next = dentry->next;
 543         }
 544 }
 545
 546
 547 /* Recalculates the length of @dentry based on its file name length and short
 548  * name length.  */
 549 static inline void recalculate_dentry_size(struct dentry *dentry)
 550 {
 551         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len +
 552                          2 + dentry->short_name_len;
 553         for (u16 i = 0; i < dentry->num_ads; i++)
 554                 dentry->length += ads_entry_length(&dentry->ads_entries[i]);
 555         /* Must be multiple of 8. */
 556         dentry->length = (dentry->length + 7) & ~7;
 557 }
 558
 559 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
 560  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
 561  * full_path_utf8 fields.  Also recalculates its length. */
 562 int change_dentry_name(struct dentry *dentry, const char *new_name)
 563 {
 564         size_t utf8_len;
 565         size_t utf16_len;
 566
 567         FREE(dentry->file_name);
 568
 569         utf8_len = strlen(new_name);
 570
 571         dentry->file_name = utf8_to_utf16(new_name, utf8_len, &utf16_len);
 572
 573         if (!dentry->file_name)
 574                 return WIMLIB_ERR_NOMEM;
 575
 576         FREE(dentry->file_name_utf8);
 577         dentry->file_name_utf8 = MALLOC(utf8_len + 1);
 578         if (!dentry->file_name_utf8) {
 579                 FREE(dentry->file_name);
 580                 dentry->file_name = NULL;
 581                 return WIMLIB_ERR_NOMEM;
 582         }
 583
 584         dentry->file_name_len = utf16_len;
 585         dentry->file_name_utf8_len = utf8_len;
 586         memcpy(dentry->file_name_utf8, new_name, utf8_len + 1);
 587         recalculate_dentry_size(dentry);
 588         return 0;
 589 }
 590
 591 /* Parameters for calculate_dentry_statistics(). */
 592 struct image_statistics {
 593         struct lookup_table *lookup_table;
 594         u64 *dir_count;
 595         u64 *file_count;
 596         u64 *total_bytes;
 597         u64 *hard_link_bytes;
 598 };
 599
 600 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
 601 {
 602         struct image_statistics *stats;
 603         struct lookup_table_entry *lte;
 604
 605         stats = arg;
 606         lte = lookup_resource(stats->lookup_table, dentry->hash);
 607
 608         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
 609                 ++*stats->dir_count;
 610         else
 611                 ++*stats->file_count;
 612
 613         if (lte) {
 614                 u64 size = lte->resource_entry.original_size;
 615                 *stats->total_bytes += size;
 616                 if (++lte->out_refcnt == 1)
 617                         *stats->hard_link_bytes += size;
 618         }
 619         return 0;
 620 }
 621
 622 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
 623                                    u64 *dir_count_ret, u64 *file_count_ret,
 624                                    u64 *total_bytes_ret,
 625                                    u64 *hard_link_bytes_ret)
 626 {
 627         struct image_statistics stats;
 628         *dir_count_ret         = 0;
 629         *file_count_ret        = 0;
 630         *total_bytes_ret       = 0;
 631         *hard_link_bytes_ret   = 0;
 632         stats.lookup_table     = table;
 633         stats.dir_count       = dir_count_ret;
 634         stats.file_count      = file_count_ret;
 635         stats.total_bytes     = total_bytes_ret;
 636         stats.hard_link_bytes = hard_link_bytes_ret;
 637         for_lookup_table_entry(table, zero_out_refcnts, NULL);
 638         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
 639 }
 640
 641 static int read_ads_entries(const u8 *p, struct dentry *dentry,
 642                             u64 remaining_size)
 643 {
 644         u16 num_ads = dentry->num_ads;
 645         struct ads_entry *ads_entries = CALLOC(num_ads, sizeof(struct ads_entry));
 646         int ret;
 647         if (!ads_entries) {
 648                 ERROR("Could not allocate memory for %"PRIu16" "
 649                       "alternate data stream entries", num_ads);
 650                 return WIMLIB_ERR_NOMEM;
 651         }
 652         DEBUG2("Reading %"PRIu16" alternate data streams "
 653                "(remaining size = %"PRIu64")", num_ads, remaining_size);
 654
 655         for (u16 i = 0; i < num_ads; i++) {
 656                 struct ads_entry *cur_entry = &ads_entries[i];
 657                 u64 length;
 658                 size_t utf8_len;
 659                 /* Read the base stream entry, excluding the stream name. */
 660                 if (remaining_size < WIM_ADS_ENTRY_DISK_SIZE) {
 661                         ERROR("Stream entries go past end of metadata resource");
 662                         ret = WIMLIB_ERR_INVALID_DENTRY;
 663                         goto out_free_ads_entries;
 664                 }
 665                 remaining_size -= WIM_ADS_ENTRY_DISK_SIZE;
 666                 /*print_string(p + 40, 10);*/
 667                 /*print_byte_field(p, 50);*/
 668
 669                 p = get_u64(p, &length); /* ADS entry length */
 670
 671                 DEBUG2("ADS length = %"PRIu64, length);
 672
 673                 p += 8; /* Unused */
 674                 p = get_bytes(p, WIM_HASH_SIZE, (u8*)cur_entry->hash);
 675                 p = get_u16(p, &cur_entry->stream_name_len);
 676
 677                 DEBUG2("Stream name length = %u", cur_entry->stream_name_len);
 678
 679                 cur_entry->stream_name = NULL;
 680                 cur_entry->stream_name_utf8 = NULL;
 681
 682                 if (remaining_size < cur_entry->stream_name_len + 2) {
 683                         ERROR("Stream entries go past end of metadata resource");
 684                         ret = WIMLIB_ERR_INVALID_DENTRY;
 685                         goto out_free_ads_entries;
 686                 }
 687                 remaining_size -= cur_entry->stream_name_len + 2;
 688
 689                 cur_entry->stream_name = MALLOC(cur_entry->stream_name_len);
 690                 if (!cur_entry->stream_name) {
 691                         ret = WIMLIB_ERR_NOMEM;
 692                         goto out_free_ads_entries;
 693                 }
 694                 p = get_bytes(p, cur_entry->stream_name_len,
 695                               (u8*)cur_entry->stream_name);
 696                 p += 2; /* NULL terminator of stream name */
 697                 cur_entry->stream_name_utf8 = utf16_to_utf8(cur_entry->stream_name,
 698                                                             cur_entry->stream_name_len,
 699                                                             &utf8_len);
 700                 cur_entry->stream_name_len_utf8 = utf8_len;
 701                 print_byte_field(p, 16);
 702
 703                 if (!cur_entry->stream_name_utf8) {
 704                         ret = WIMLIB_ERR_NOMEM;
 705                         goto out_free_ads_entries;
 706                 }
 707         }
 708         dentry->ads_entries = ads_entries;
 709         return 0;
 710 out_free_ads_entries:
 711         for (u16 i = 0; i < num_ads; i++) {
 712                 FREE(ads_entries[i].stream_name);
 713                 FREE(ads_entries[i].stream_name_utf8);
 714         }
 715         FREE(ads_entries);
 716         return ret;
 717 }
 718
 719 /*
 720  * Reads a directory entry from the metadata resource.
 721  */
 722 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
 723                 u64 offset, struct dentry *dentry)
 724 {
 725         const u8 *p;
 726         u64 calculated_size;
 727         char *file_name;
 728         char *file_name_utf8;
 729         char *short_name;
 730         u16 short_name_len;
 731         u16 file_name_len;
 732         size_t file_name_utf8_len;
 733         int ret;
 734
 735         dentry_common_init(dentry);
 736
 737         /*Make sure the dentry really fits into the metadata resource.*/
 738         if (offset + 8 > metadata_resource_len) {
 739                 ERROR("Directory entry starting at %"PRIu64" ends past the "
 740                       "end of the metadata resource (size %"PRIu64")",
 741                       offset, metadata_resource_len);
 742                 return WIMLIB_ERR_INVALID_DENTRY;
 743         }
 744
 745         /* Before reading the whole entry, we need to read just the length.
 746          * This is because an entry of length 8 (that is, just the length field)
 747          * terminates the list of sibling directory entries. */
 748
 749         p = get_u64(&metadata_resource[offset], &dentry->length);
 750         DEBUG("length = %zu, %zu\n", dentry->length, *(u64*)(&metadata_resource[offset]));
 751
 752         /* A zero length field (really a length of 8, since that's how big the
 753          * directory entry is...) indicates that this is the end of directory
 754          * dentry.  We do not read it into memory as an actual dentry, so just
 755          * return true in that case. */
 756         if (dentry->length == 0)
 757                 return 0;
 758
 759         if (offset + dentry->length >= metadata_resource_len) {
 760                 ERROR("Directory entry at offset %"PRIu64" and with size "
 761                       "%"PRIu64" ends past the end of the metadata resource "
 762                       "(size %"PRIu64")",
 763                       offset, dentry->length, metadata_resource_len);
 764                 return WIMLIB_ERR_INVALID_DENTRY;
 765         }
 766
 767         /* If it is a recognized length, read the rest of the directory entry.
 768          * Note: The root directory entry has no name, and its length does not
 769          * include the short name length field.  */
 770         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
 771                 ERROR("Directory entry has invalid length of %"PRIu64" bytes",
 772                       dentry->length);
 773                 return WIMLIB_ERR_INVALID_DENTRY;
 774         }
 775
 776         p = get_u32(p, &dentry->attributes);
 777         p = get_u32(p, (u32*)&dentry->security_id);
 778         p = get_u64(p, &dentry->subdir_offset);
 779
 780         /* 2 unused fields */
 781         p += 2 * sizeof(u64);
 782         /*p = get_u64(p, &dentry->unused1);*/
 783         /*p = get_u64(p, &dentry->unused2);*/
 784
 785         p = get_u64(p, &dentry->creation_time);
 786         p = get_u64(p, &dentry->last_access_time);
 787         p = get_u64(p, &dentry->last_write_time);
 788
 789         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
 790
 791         /*
 792          * I don't know what's going on here.  It seems like M$ screwed up the
 793          * reparse points, then put the fields in the same place and didn't
 794          * document it.  The WIM_HDR_FLAG_RP_FIX flag in the WIM header might
 795          * have something to do with this, but it's not documented.
 796          */
 797         if (dentry->attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
 798                 /* ??? */
 799                 u32 u1, u2;
 800                 p = get_u32(p, &u1);
 801                 /*p += 4;*/
 802                 p = get_u32(p, &dentry->reparse_tag);
 803                 p = get_u32(p, &u2);
 804                 /*p += 4;*/
 805                 dentry->hard_link = (u64)(u1) | ((u64)(u2) << 32);
 806         } else {
 807                 p = get_u32(p, &dentry->reparse_tag);
 808                 p = get_u64(p, &dentry->hard_link);
 809         }
 810
 811         /* By the way, the reparse_reserved field does not actually exist (at
 812          * least when the file is not a reparse point) */
 813
 814
 815         p = get_u16(p, &dentry->num_ads);
 816
 817         p = get_u16(p, &short_name_len);
 818         p = get_u16(p, &file_name_len);
 819
 820         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
 821                           short_name_len;
 822
 823         if (dentry->length < calculated_size) {
 824                 ERROR("Unexpected end of directory entry! (Expected "
 825                       "%"PRIu64" bytes, got %"PRIu64" bytes. "
 826                       "short_name_len = %hu, file_name_len = %hu)",
 827                       calculated_size, dentry->length,
 828                       short_name_len, file_name_len);
 829                 return WIMLIB_ERR_INVALID_DENTRY;
 830         }
 831
 832         /* Read the filename. */
 833         file_name = MALLOC(file_name_len);
 834         if (!file_name) {
 835                 ERROR("Failed to allocate %hu bytes for dentry file name",
 836                       file_name_len);
 837                 return WIMLIB_ERR_NOMEM;
 838         }
 839         p = get_bytes(p, file_name_len, file_name);
 840
 841         /* Convert filename to UTF-8. */
 842         file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
 843                                        &file_name_utf8_len);
 844
 845         if (!file_name_utf8) {
 846                 ERROR("Failed to allocate memory to convert UTF-16 "
 847                       "filename (%hu bytes) to UTF-8", file_name_len);
 848                 ret = WIMLIB_ERR_NOMEM;
 849                 goto out_free_file_name;
 850         }
 851
 852         /* Undocumented padding between file name and short name.  This probably
 853          * is supposed to be a terminating null character. */
 854         p += 2;
 855
 856         /* Read the short filename. */
 857         short_name = MALLOC(short_name_len);
 858         if (!short_name) {
 859                 ERROR("Failed to allocate %hu bytes for short filename",
 860                       short_name_len);
 861                 ret = WIMLIB_ERR_NOMEM;
 862                 goto out_free_file_name_utf8;
 863         }
 864
 865         p = get_bytes(p, short_name_len, short_name);
 866
 867         /* Some directory entries inexplicibly have a little over 70 bytes of
 868          * extra data.  The exact amount of data seems to be 72 bytes, but it is
 869          * aligned on the next 8-byte boundary.  Here's an example of the
 870          * aligned data:
 871          *
 872          * 01000000400000006c786bbac58ede11b0bb00261870892ab6adb76fe63a3
 873          * e468fca86530d2effa16c786bbac58ede11b0bb00261870892a0000000000
 874          * 0000000000000000000000
 875          *
 876          * Here's one interpretation of how the data is laid out.
 877          *
 878          * struct unknown {
 879          *      u32 field1; (always 0x00000001)
 880          *      u32 field2; (always 0x40000000)
 881          *      u16 field3;
 882          *      u32 field4;
 883          *      u32 field5;
 884          *      u32 field6;
 885          *      u8  data[48]; (???)
 886          *      u64 reserved1; (always 0)
 887          *      u64 reserved2; (always 0)
 888          * };*/
 889 #if 0
 890         if (dentry->length - calculated_size >= WIM_ADS_ENTRY_DISK_SIZE) {
 891                 printf("%s: %lu / %lu (", file_name_utf8,
 892                                 calculated_size, dentry->length);
 893                 print_string(p + WIM_ADS_ENTRY_DISK_SIZE, dentry->length - calculated_size - WIM_ADS_ENTRY_DISK_SIZE);
 894                 puts(")");
 895                 print_byte_field(p, dentry->length - calculated_size);
 896                 putchar('\n');
 897         }
 898 #endif
 899
 900         if (dentry->num_ads != 0) {
 901                 ret = read_ads_entries(p, dentry,
 902                                        metadata_resource_len - offset - calculated_size);
 903                 if (ret != 0)
 904                         goto out_free_short_name;
 905         }
 906
 907         dentry->file_name          = file_name;
 908         dentry->file_name_utf8     = file_name_utf8;
 909         dentry->short_name         = short_name;
 910         dentry->file_name_len      = file_name_len;
 911         dentry->file_name_utf8_len = file_name_utf8_len;
 912         dentry->short_name_len     = short_name_len;
 913         return 0;
 914 out_free_short_name:
 915         FREE(short_name);
 916 out_free_file_name_utf8:
 917         FREE(file_name_utf8);
 918 out_free_file_name:
 919         FREE(file_name);
 920         return ret;
 921 }
 922
 923 /*
 924  * Writes a dentry to an output buffer.
 925  *
 926  * @dentry:  The dentry structure.
 927  * @p:       The memory location to write the data to.
 928  * @return:  Pointer to the byte after the last byte we wrote as part of the
 929  *              dentry.
 930  */
 931 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
 932 {
 933         u8 *orig_p = p;
 934         memset(p, 0, dentry->length);
 935         p = put_u64(p, dentry->length);
 936         p = put_u32(p, dentry->attributes);
 937         p = put_u32(p, dentry->security_id);
 938         p = put_u64(p, dentry->subdir_offset);
 939         p = put_u64(p, 0); /* unused1 */
 940         p = put_u64(p, 0); /* unused2 */
 941         p = put_u64(p, dentry->creation_time);
 942         p = put_u64(p, dentry->last_access_time);
 943         p = put_u64(p, dentry->last_write_time);
 944         memcpy(p, dentry->hash, WIM_HASH_SIZE);
 945         p += WIM_HASH_SIZE;
 946         p = put_u32(p, dentry->reparse_tag);
 947         p = put_u64(p, dentry->hard_link);
 948         p = put_u16(p, dentry->num_ads); /*streams */
 949         p = put_u16(p, dentry->short_name_len);
 950         p = put_u16(p, dentry->file_name_len);
 951         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
 952         p = put_u16(p, 0); /* filename padding, 2 bytes. */
 953         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
 954         for (u16 i = 0; i < dentry->num_ads; i++) {
 955                 p = put_u64(p, ads_entry_length(&dentry->ads_entries[i]));
 956                 p = put_u64(p, 0); /* Unused */
 957                 p = put_bytes(p, WIM_HASH_SIZE, dentry->ads_entries[i].hash);
 958                 p = put_u16(p, dentry->ads_entries[i].stream_name_len);
 959                 p = put_bytes(p, dentry->ads_entries[i].stream_name_len,
 960                                  (u8*)dentry->ads_entries[i].stream_name);
 961         }
 962         return orig_p + dentry->length;
 963 }
 964
 965 /* Recursive function that writes a dentry tree rooted at @tree, not including
 966  * @tree itself, which has already been written, except in the case of the root
 967  * dentry, which is written right away, along with an end-of-directory entry. */
 968 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
 969 {
 970         const struct dentry *child;
 971
 972         if (dentry_is_root(tree)) {
 973                 p = write_dentry(tree, p);
 974
 975                 /* write end of directory entry */
 976                 p = put_u64(p, 0);
 977         } else {
 978                 /* Nothing to do for a regular file. */
 979                 if (dentry_is_regular_file(tree))
 980                         return p;
 981         }
 982
 983         /* Write child dentries and end-of-directory entry. */
 984         child = tree->children;
 985         if (child) {
 986                 do {
 987                         p = write_dentry(child, p);
 988                         child = child->next;
 989                 } while (child != tree->children);
 990         }
 991
 992         /* write end of directory entry */
 993         p = put_u64(p, 0);
 994
 995         /* Recurse on children. */
 996         if (child) {
 997                 do {
 998                         p = write_dentry_tree(child, p);
 999                         child = child->next;
1000                 } while (child != tree->children);
1001         }
1002         return p;
1003 }
1004
1005 /* Reads the children of a dentry, and all their children, ..., etc. from the
1006  * metadata resource and into the dentry tree.
1007  *
1008  * @metadata_resource:  An array that contains the uncompressed metadata
1009  *                      resource for the WIM file.
1010  * @metadata_resource_len:      The length of @metadata_resource.
1011  * @dentry:     A pointer to a struct dentry that is the root of the directory
1012  *              tree and has already been read from the metadata resource.  It
1013  *              does not need to be the real root because this procedure is
1014  *              called recursively.
1015  *
1016  * @return:     Zero on success, nonzero on failure.
1017  */
1018 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
1019                      struct dentry *dentry)
1020 {
1021         u64 cur_offset = dentry->subdir_offset;
1022         struct dentry *prev_child = NULL;
1023         struct dentry *first_child = NULL;
1024         struct dentry *child;
1025         struct dentry cur_child;
1026         int ret;
1027
1028         /* If @dentry is a regular file, nothing more needs to be done for this
1029          * branch. */
1030         if (cur_offset == 0)
1031                 return 0;
1032
1033         /* Find and read all the children of @dentry. */
1034         while (1) {
1035
1036                 /* Read next child of @dentry into @cur_child. */
1037                 ret = read_dentry(metadata_resource, metadata_resource_len,
1038                                   cur_offset, &cur_child);
1039                 if (ret != 0)
1040                         break;
1041
1042                 /* Check for end of directory. */
1043                 if (cur_child.length == 0) {
1044                         ret = 0;
1045                         break;
1046                 }
1047
1048                 /* Not end of directory.  Allocate this child permanently and
1049                  * link it to the parent and previous child. */
1050                 child = MALLOC(sizeof(struct dentry));
1051                 if (!child) {
1052                         ERROR("Failed to allocate %zu bytes for new dentry",
1053                               sizeof(struct dentry));
1054                         ret = WIMLIB_ERR_NOMEM;
1055                         break;
1056                 }
1057                 memcpy(child, &cur_child, sizeof(struct dentry));
1058
1059                 if (prev_child) {
1060                         prev_child->next = child;
1061                         child->prev = prev_child;
1062                 } else {
1063                         first_child = child;
1064                 }
1065
1066                 child->parent = dentry;
1067                 prev_child = child;
1068
1069                 /* If there are children of this child, call this procedure
1070                  * recursively. */
1071                 if (child->subdir_offset != 0) {
1072                         ret = read_dentry_tree(metadata_resource,
1073                                                metadata_resource_len, child);
1074                         if (ret != 0)
1075                                 break;
1076                 }
1077
1078                 /* Advance to the offset of the next child. */
1079                 cur_offset += dentry_total_length(child);
1080         }
1081
1082         /* Link last child to first one, and set parent's
1083          * children pointer to the first child.  */
1084         if (prev_child) {
1085                 prev_child->next = first_child;
1086                 first_child->prev = prev_child;
1087         }
1088         dentry->children = first_child;
1089         return ret;
1090 }