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
14 * Copyright (C) 2010 Carl Thijssen
15 * Copyright (C) 2012 Eric Biggers
17 * This file is part of wimlib, a library for working with WIM files.
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)
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
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/.
40 #include "lookup_table.h"
42 #include "timestamp.h"
43 #include "wimlib_internal.h"
46 * Returns true if @dentry has the UTF-8 file name @name that has length
49 static bool dentry_has_name(const struct dentry *dentry, const char *name,
52 if (dentry->file_name_utf8_len != name_len)
54 return memcmp(dentry->file_name_utf8, name, name_len) == 0;
57 static u64 __dentry_correct_length_unaligned(u16 file_name_len,
60 u64 length = WIM_DENTRY_DISK_SIZE;
62 length += file_name_len + 2;
64 length += short_name_len + 2;
68 static u64 dentry_correct_length_unaligned(const struct dentry *dentry)
70 return __dentry_correct_length_unaligned(dentry->file_name_len,
71 dentry->short_name_len);
74 /* Return the "correct" value to write in the length field of the dentry, based
75 * on the file name length and short name length */
76 static u64 dentry_correct_length(const struct dentry *dentry)
78 return (dentry_correct_length_unaligned(dentry) + 7) & ~7;
81 static u64 __dentry_total_length(const struct dentry *dentry, u64 length)
83 for (u16 i = 0; i < dentry->num_ads; i++)
84 length += ads_entry_total_length(&dentry->ads_entries[i]);
85 return (length + 7) & ~7;
88 u64 dentry_correct_total_length(const struct dentry *dentry)
90 return __dentry_total_length(dentry,
91 dentry_correct_length_unaligned(dentry));
94 /* Real length of a dentry, including the alternate data stream entries, which
95 * are not included in the dentry->length field... */
96 u64 dentry_total_length(const struct dentry *dentry)
98 return __dentry_total_length(dentry, dentry->length);
101 /* Transfers file attributes from a `stat' buffer to a struct dentry. */
102 void stbuf_to_dentry(const struct stat *stbuf, struct dentry *dentry)
104 if (S_ISLNK(stbuf->st_mode)) {
105 dentry->attributes = FILE_ATTRIBUTE_REPARSE_POINT;
106 dentry->reparse_tag = WIM_IO_REPARSE_TAG_SYMLINK;
107 } else if (S_ISDIR(stbuf->st_mode)) {
108 dentry->attributes = FILE_ATTRIBUTE_DIRECTORY;
110 dentry->attributes = FILE_ATTRIBUTE_NORMAL;
112 if (sizeof(ino_t) >= 8)
113 dentry->hard_link = (u64)stbuf->st_ino;
115 dentry->hard_link = (u64)stbuf->st_ino |
116 ((u64)stbuf->st_dev << (sizeof(ino_t) * 8));
118 dentry->creation_time = timespec_to_wim_timestamp(&stbuf->st_mtim);
119 dentry->last_write_time = timespec_to_wim_timestamp(&stbuf->st_mtim);
120 dentry->last_access_time = timespec_to_wim_timestamp(&stbuf->st_atim);
124 /* Sets all the timestamp fields of the dentry to the current time. */
125 void dentry_update_all_timestamps(struct dentry *dentry)
127 u64 now = get_wim_timestamp();
128 dentry->creation_time = now;
129 dentry->last_access_time = now;
130 dentry->last_write_time = now;
133 /* Returns the alternate data stream entry belonging to @dentry that has the
134 * stream name @stream_name. */
135 struct ads_entry *dentry_get_ads_entry(struct dentry *dentry,
136 const char *stream_name)
138 size_t stream_name_len;
141 if (dentry->num_ads) {
143 stream_name_len = strlen(stream_name);
145 if (ads_entry_has_name(&dentry->ads_entries[i],
146 stream_name, stream_name_len))
147 return &dentry->ads_entries[i];
148 } while (++i != dentry->num_ads);
153 static void ads_entry_init(struct ads_entry *ads_entry)
155 memset(ads_entry, 0, sizeof(struct ads_entry));
156 INIT_LIST_HEAD(&ads_entry->lte_group_list.list);
157 ads_entry->lte_group_list.type = STREAM_TYPE_ADS;
161 * Add an alternate stream entry to a dentry and return a pointer to it, or NULL
162 * if memory could not be allocated.
164 struct ads_entry *dentry_add_ads(struct dentry *dentry, const char *stream_name)
167 struct ads_entry *ads_entries;
168 struct ads_entry *new_entry;
170 DEBUG("Add alternate data stream %s:%s",
171 dentry->file_name_utf8, stream_name);
173 if (dentry->num_ads == 0xffff)
175 num_ads = dentry->num_ads + 1;
176 ads_entries = REALLOC(dentry->ads_entries,
177 num_ads * sizeof(struct ads_entry));
180 if (ads_entries != dentry->ads_entries) {
181 /* We moved the ADS entries. Adjust the stream lists. */
182 for (u16 i = 0; i < dentry->num_ads; i++) {
183 struct list_head *cur = &ads_entries[i].lte_group_list.list;
184 cur->prev->next = cur;
185 cur->next->prev = cur;
189 new_entry = &ads_entries[num_ads - 1];
190 ads_entry_init(new_entry);
191 if (change_ads_name(new_entry, stream_name) != 0)
193 dentry->ads_entries = ads_entries;
194 dentry->num_ads = num_ads;
198 /* Remove an alternate data stream from a dentry.
200 * The corresponding lookup table entry for the stream is NOT changed.
202 * @dentry: The dentry
203 * @ads_entry: The alternate data stream entry (it MUST be one of the
204 * ads_entry's in the array dentry->ads_entries).
206 void dentry_remove_ads(struct dentry *dentry, struct ads_entry *ads_entry)
211 wimlib_assert(dentry->num_ads);
212 idx = ads_entry - dentry->ads_entries;
213 wimlib_assert(idx < dentry->num_ads);
214 following = dentry->num_ads - idx - 1;
216 destroy_ads_entry(ads_entry);
217 memcpy(ads_entry, ads_entry + 1, following * sizeof(struct ads_entry));
219 /* We moved the ADS entries. Adjust the stream lists. */
220 for (u16 i = 0; i < following; i++) {
221 struct list_head *cur = &ads_entry[i].lte_group_list.list;
222 cur->prev->next = cur;
223 cur->next->prev = cur;
230 * Calls a function on all directory entries in a directory tree. It is called
231 * on a parent before its children.
233 int for_dentry_in_tree(struct dentry *root,
234 int (*visitor)(struct dentry*, void*), void *arg)
237 struct dentry *child;
239 ret = visitor(root, arg);
244 child = root->children;
250 ret = for_dentry_in_tree(child, visitor, arg);
254 } while (child != root->children);
259 * Like for_dentry_in_tree(), but the visitor function is always called on a
260 * dentry's children before on itself.
262 int for_dentry_in_tree_depth(struct dentry *root,
263 int (*visitor)(struct dentry*, void*), void *arg)
266 struct dentry *child;
269 child = root->children;
273 ret = for_dentry_in_tree_depth(child, visitor, arg);
277 } while (child != root->children);
279 return visitor(root, arg);
283 * Calculate the full path of @dentry, based on its parent's full path and on
284 * its UTF-8 file name.
286 int calculate_dentry_full_path(struct dentry *dentry, void *ignore)
290 if (dentry_is_root(dentry)) {
291 full_path = MALLOC(2);
298 char *parent_full_path;
299 u32 parent_full_path_len;
300 const struct dentry *parent = dentry->parent;
302 if (dentry_is_root(parent)) {
303 parent_full_path = "";
304 parent_full_path_len = 0;
306 parent_full_path = parent->full_path_utf8;
307 parent_full_path_len = parent->full_path_utf8_len;
310 full_path_len = parent_full_path_len + 1 +
311 dentry->file_name_utf8_len;
312 full_path = MALLOC(full_path_len + 1);
316 memcpy(full_path, parent_full_path, parent_full_path_len);
317 full_path[parent_full_path_len] = '/';
318 memcpy(full_path + parent_full_path_len + 1,
319 dentry->file_name_utf8,
320 dentry->file_name_utf8_len);
321 full_path[full_path_len] = '\0';
323 FREE(dentry->full_path_utf8);
324 dentry->full_path_utf8 = full_path;
325 dentry->full_path_utf8_len = full_path_len;
328 ERROR("Out of memory while calculating dentry full path");
329 return WIMLIB_ERR_NOMEM;
333 * Recursively calculates the subdir offsets for a directory tree.
335 * @dentry: The root of the directory tree.
336 * @subdir_offset_p: The current subdirectory offset; i.e., the subdirectory
337 * offset for @dentry.
339 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
341 struct dentry *child;
343 child = dentry->children;
344 dentry->subdir_offset = *subdir_offset_p;
347 /* Advance the subdir offset by the amount of space the children
348 * of this dentry take up. */
350 *subdir_offset_p += dentry_correct_total_length(child);
352 } while (child != dentry->children);
354 /* End-of-directory dentry on disk. */
355 *subdir_offset_p += 8;
357 /* Recursively call calculate_subdir_offsets() on all the
360 calculate_subdir_offsets(child, subdir_offset_p);
362 } while (child != dentry->children);
364 /* On disk, childless directories have a valid subdir_offset
365 * that points to an 8-byte end-of-directory dentry. Regular
366 * files or reparse points have a subdir_offset of 0. */
367 if (dentry_is_directory(dentry))
368 *subdir_offset_p += 8;
370 dentry->subdir_offset = 0;
375 /* Returns the child of @dentry that has the file name @name.
376 * Returns NULL if no child has the name. */
377 struct dentry *get_dentry_child_with_name(const struct dentry *dentry,
380 struct dentry *child;
383 child = dentry->children;
385 name_len = strlen(name);
387 if (dentry_has_name(child, name, name_len))
390 } while (child != dentry->children);
395 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
396 * @cur_dir. Returns NULL if no dentry having the path is found. */
397 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir,
400 struct dentry *child;
402 const char *new_path;
407 child = cur_dir->children;
409 new_path = path_next_part(path, &base_len);
411 if (dentry_has_name(child, path, base_len))
412 return get_dentry_relative_path(child, new_path);
414 } while (child != cur_dir->children);
419 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
421 struct dentry *get_dentry(WIMStruct *w, const char *path)
423 struct dentry *root = wim_root_dentry(w);
426 return get_dentry_relative_path(root, path);
429 /* Returns the dentry that corresponds to the parent directory of @path, or NULL
430 * if the dentry is not found. */
431 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
433 size_t path_len = strlen(path);
434 char buf[path_len + 1];
436 memcpy(buf, path, path_len + 1);
438 to_parent_name(buf, path_len);
440 return get_dentry(w, buf);
443 /* Prints the full path of a dentry. */
444 int print_dentry_full_path(struct dentry *dentry, void *ignore)
446 if (dentry->full_path_utf8)
447 puts(dentry->full_path_utf8);
451 /* We want to be able to show the names of the file attribute flags that are
453 struct file_attr_flag {
457 struct file_attr_flag file_attr_flags[] = {
458 {FILE_ATTRIBUTE_READONLY, "READONLY"},
459 {FILE_ATTRIBUTE_HIDDEN, "HIDDEN"},
460 {FILE_ATTRIBUTE_SYSTEM, "SYSTEM"},
461 {FILE_ATTRIBUTE_DIRECTORY, "DIRECTORY"},
462 {FILE_ATTRIBUTE_ARCHIVE, "ARCHIVE"},
463 {FILE_ATTRIBUTE_DEVICE, "DEVICE"},
464 {FILE_ATTRIBUTE_NORMAL, "NORMAL"},
465 {FILE_ATTRIBUTE_TEMPORARY, "TEMPORARY"},
466 {FILE_ATTRIBUTE_SPARSE_FILE, "SPARSE_FILE"},
467 {FILE_ATTRIBUTE_REPARSE_POINT, "REPARSE_POINT"},
468 {FILE_ATTRIBUTE_COMPRESSED, "COMPRESSED"},
469 {FILE_ATTRIBUTE_OFFLINE, "OFFLINE"},
470 {FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,"NOT_CONTENT_INDEXED"},
471 {FILE_ATTRIBUTE_ENCRYPTED, "ENCRYPTED"},
472 {FILE_ATTRIBUTE_VIRTUAL, "VIRTUAL"},
475 /* Prints a directory entry. @lookup_table is a pointer to the lookup table, if
476 * available. If the dentry is unresolved and the lookup table is NULL, the
477 * lookup table entries will not be printed. Otherwise, they will be. */
478 int print_dentry(struct dentry *dentry, void *lookup_table)
481 struct lookup_table_entry *lte;
483 printf("[DENTRY]\n");
484 printf("Length = %"PRIu64"\n", dentry->length);
485 printf("Attributes = 0x%x\n", dentry->attributes);
486 for (unsigned i = 0; i < ARRAY_LEN(file_attr_flags); i++)
487 if (file_attr_flags[i].flag & dentry->attributes)
488 printf(" FILE_ATTRIBUTE_%s is set\n",
489 file_attr_flags[i].name);
490 printf("Security ID = %d\n", dentry->security_id);
491 printf("Subdir offset = %"PRIu64"\n", dentry->subdir_offset);
493 printf("Unused1 = 0x%"PRIu64"\n", dentry->unused1);
494 printf("Unused2 = %"PRIu64"\n", dentry->unused2);
497 printf("Creation Time = 0x%"PRIx64"\n");
498 printf("Last Access Time = 0x%"PRIx64"\n");
499 printf("Last Write Time = 0x%"PRIx64"\n");
502 /* Translate the timestamps into something readable */
503 time_t creat_time = wim_timestamp_to_unix(dentry->creation_time);
504 time_t access_time = wim_timestamp_to_unix(dentry->last_access_time);
505 time_t mod_time = wim_timestamp_to_unix(dentry->last_write_time);
506 printf("Creation Time = %s", asctime(gmtime(&creat_time)));
507 printf("Last Access Time = %s", asctime(gmtime(&access_time)));
508 printf("Last Write Time = %s", asctime(gmtime(&mod_time)));
510 printf("Reparse Tag = 0x%"PRIx32"\n", dentry->reparse_tag);
511 printf("Hard Link Group = 0x%"PRIx64"\n", dentry->hard_link);
512 printf("Number of Alternate Data Streams = %hu\n", dentry->num_ads);
513 printf("Filename = \"");
514 print_string(dentry->file_name, dentry->file_name_len);
516 printf("Filename Length = %hu\n", dentry->file_name_len);
517 printf("Filename (UTF-8) = \"%s\"\n", dentry->file_name_utf8);
518 printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
519 printf("Short Name = \"");
520 print_string(dentry->short_name, dentry->short_name_len);
522 printf("Short Name Length = %hu\n", dentry->short_name_len);
523 printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
524 lte = dentry_stream_lte(dentry, 0, lookup_table);
526 print_lookup_table_entry(lte);
528 hash = dentry_stream_hash(dentry, 0);
536 for (u16 i = 0; i < dentry->num_ads; i++) {
537 printf("[Alternate Stream Entry %u]\n", i);
538 printf("Name = \"%s\"\n", dentry->ads_entries[i].stream_name_utf8);
539 printf("Name Length (UTF-16) = %u\n",
540 dentry->ads_entries[i].stream_name_len);
541 hash = dentry_stream_hash(dentry, i + 1);
547 print_lookup_table_entry(dentry_stream_lte(dentry, i + 1,
553 /* Initializations done on every `struct dentry'. */
554 static void dentry_common_init(struct dentry *dentry)
556 memset(dentry, 0, sizeof(struct dentry));
558 dentry->security_id = -1;
559 dentry->ads_entries_status = ADS_ENTRIES_DEFAULT;
560 dentry->lte_group_list.type = STREAM_TYPE_NORMAL;
564 * Creates an unlinked directory entry.
566 * @name: The UTF-8 filename of the new dentry.
568 * Returns a pointer to the new dentry, or NULL if out of memory.
570 struct dentry *new_dentry(const char *name)
572 struct dentry *dentry;
574 dentry = MALLOC(sizeof(struct dentry));
578 dentry_common_init(dentry);
579 if (change_dentry_name(dentry, name) != 0)
582 dentry_update_all_timestamps(dentry);
583 dentry->next = dentry;
584 dentry->prev = dentry;
585 dentry->parent = dentry;
586 INIT_LIST_HEAD(&dentry->link_group_list);
590 ERROR("Failed to allocate new dentry");
594 void dentry_free_ads_entries(struct dentry *dentry)
596 for (u16 i = 0; i < dentry->num_ads; i++)
597 destroy_ads_entry(&dentry->ads_entries[i]);
598 FREE(dentry->ads_entries);
599 dentry->ads_entries = NULL;
603 static void __destroy_dentry(struct dentry *dentry)
605 FREE(dentry->file_name);
606 FREE(dentry->file_name_utf8);
607 FREE(dentry->short_name);
608 FREE(dentry->full_path_utf8);
609 FREE(dentry->extracted_file);
612 /* Frees a WIM dentry. */
613 void free_dentry(struct dentry *dentry)
615 wimlib_assert(dentry);
616 __destroy_dentry(dentry);
617 /* Don't destroy the ADS entries if they "belong" to a different dentry
619 if (dentry->ads_entries_status != ADS_ENTRIES_USER)
620 dentry_free_ads_entries(dentry);
624 /* Like free_dentry(), but assigns a new ADS entries owner if this dentry was
625 * the previous owner, and also deletes the dentry from its link_group_list */
626 void put_dentry(struct dentry *dentry)
628 if (dentry->ads_entries_status == ADS_ENTRIES_OWNER) {
629 struct dentry *new_owner;
630 list_for_each_entry(new_owner, &dentry->link_group_list,
633 if (new_owner->ads_entries_status == ADS_ENTRIES_USER) {
634 new_owner->ads_entries_status = ADS_ENTRIES_OWNER;
638 dentry->ads_entries_status = ADS_ENTRIES_USER;
640 struct list_head *next;
641 list_del(&dentry->link_group_list);
646 /* Partically clones a dentry.
649 * - memory for file names is not cloned (the pointers are all set to NULL
650 * and the lengths are set to zero)
651 * - next, prev, and children pointers and not touched
652 * - stream entries are not cloned (pointer left untouched).
654 struct dentry *clone_dentry(struct dentry *old)
656 struct dentry *new = MALLOC(sizeof(struct dentry));
659 memcpy(new, old, sizeof(struct dentry));
660 new->file_name = NULL;
661 new->file_name_len = 0;
662 new->file_name_utf8 = NULL;
663 new->file_name_utf8_len = 0;
664 new->short_name = NULL;
665 new->short_name_len = 0;
670 * This function is passed as an argument to for_dentry_in_tree_depth() in order
671 * to free a directory tree. __args is a pointer to a `struct free_dentry_args'.
673 static int do_free_dentry(struct dentry *dentry, void *__lookup_table)
675 struct lookup_table *lookup_table = __lookup_table;
676 struct lookup_table_entry *lte;
680 for (i = 0; i <= dentry->num_ads; i++) {
681 lte = dentry_stream_lte(dentry, i, lookup_table);
682 lte_decrement_refcnt(lte, lookup_table);
686 wimlib_assert(dentry->refcnt != 0);
687 if (--dentry->refcnt == 0)
693 * Unlinks and frees a dentry tree.
695 * @root: The root of the tree.
696 * @lookup_table: The lookup table for dentries. If non-NULL, the
697 * reference counts in the lookup table for the lookup
698 * table entries corresponding to the dentries will be
701 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table)
703 if (!root || !root->parent)
705 for_dentry_in_tree_depth(root, do_free_dentry, lookup_table);
708 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
715 * Links a dentry into the directory tree.
717 * @dentry: The dentry to link.
718 * @parent: The dentry that will be the parent of @dentry.
720 void link_dentry(struct dentry *dentry, struct dentry *parent)
722 wimlib_assert(dentry_is_directory(parent));
723 dentry->parent = parent;
724 if (parent->children) {
725 /* Not an only child; link to siblings. */
726 dentry->next = parent->children;
727 dentry->prev = parent->children->prev;
728 dentry->next->prev = dentry;
729 dentry->prev->next = dentry;
731 /* Only child; link to parent. */
732 parent->children = dentry;
733 dentry->next = dentry;
734 dentry->prev = dentry;
739 /* Unlink a dentry from the directory tree.
741 * Note: This merely removes it from the in-memory tree structure. See
742 * remove_dentry() in mount.c for a function implemented on top of this one that
743 * frees the dentry and implements reference counting for the lookup table
745 void unlink_dentry(struct dentry *dentry)
747 if (dentry_is_root(dentry))
749 if (dentry_is_only_child(dentry)) {
750 dentry->parent->children = NULL;
752 if (dentry_is_first_sibling(dentry))
753 dentry->parent->children = dentry->next;
754 dentry->next->prev = dentry->prev;
755 dentry->prev->next = dentry->next;
759 /* Duplicates a UTF-8 name into UTF-8 and UTF-16 strings and returns the strings
760 * and their lengths in the pointer arguments */
761 int get_names(char **name_utf16_ret, char **name_utf8_ret,
762 u16 *name_utf16_len_ret, u16 *name_utf8_len_ret,
767 char *name_utf16, *name_utf8;
769 utf8_len = strlen(name);
771 name_utf16 = utf8_to_utf16(name, utf8_len, &utf16_len);
774 return WIMLIB_ERR_NOMEM;
776 name_utf8 = MALLOC(utf8_len + 1);
779 return WIMLIB_ERR_NOMEM;
781 memcpy(name_utf8, name, utf8_len + 1);
782 FREE(*name_utf8_ret);
783 FREE(*name_utf16_ret);
784 *name_utf8_ret = name_utf8;
785 *name_utf16_ret = name_utf16;
786 *name_utf8_len_ret = utf8_len;
787 *name_utf16_len_ret = utf16_len;
791 /* Changes the name of a dentry to @new_name. Only changes the file_name and
792 * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
793 * full_path_utf8 fields. Also recalculates its length. */
794 int change_dentry_name(struct dentry *dentry, const char *new_name)
798 ret = get_names(&dentry->file_name, &dentry->file_name_utf8,
799 &dentry->file_name_len, &dentry->file_name_utf8_len,
802 dentry->length = dentry_correct_length(dentry);
807 * Changes the name of an alternate data stream */
808 int change_ads_name(struct ads_entry *entry, const char *new_name)
810 return get_names(&entry->stream_name, &entry->stream_name_utf8,
811 &entry->stream_name_len,
812 &entry->stream_name_utf8_len,
816 /* Parameters for calculate_dentry_statistics(). */
817 struct image_statistics {
818 struct lookup_table *lookup_table;
822 u64 *hard_link_bytes;
825 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
827 struct image_statistics *stats;
828 struct lookup_table_entry *lte;
832 if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
835 ++*stats->file_count;
837 for (unsigned i = 0; i <= dentry->num_ads; i++) {
838 lte = dentry_stream_lte(dentry, i, stats->lookup_table);
840 *stats->total_bytes += wim_resource_size(lte);
841 if (++lte->out_refcnt == 1)
842 *stats->hard_link_bytes += wim_resource_size(lte);
848 /* Calculates some statistics about a dentry tree. */
849 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table,
850 u64 *dir_count_ret, u64 *file_count_ret,
851 u64 *total_bytes_ret,
852 u64 *hard_link_bytes_ret)
854 struct image_statistics stats;
857 *total_bytes_ret = 0;
858 *hard_link_bytes_ret = 0;
859 stats.lookup_table = table;
860 stats.dir_count = dir_count_ret;
861 stats.file_count = file_count_ret;
862 stats.total_bytes = total_bytes_ret;
863 stats.hard_link_bytes = hard_link_bytes_ret;
864 for_lookup_table_entry(table, zero_out_refcnts, NULL);
865 for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
870 * Reads the alternate data stream entries for a dentry.
872 * @p: Pointer to buffer that starts with the first alternate stream entry.
874 * @dentry: Dentry to load the alternate data streams into.
875 * @dentry->num_ads must have been set to the number of
876 * alternate data streams that are expected.
878 * @remaining_size: Number of bytes of data remaining in the buffer pointed
881 * The format of the on-disk alternate stream entries is as follows:
883 * struct ads_entry_on_disk {
884 * u64 length; // Length of the entry, in bytes. This includes
885 * all fields (including the stream name and
886 * null terminator if present, AND the padding!).
887 * u64 reserved; // Seems to be unused
888 * u8 hash[20]; // SHA1 message digest of the uncompressed stream
889 * u16 stream_name_len; // Length of the stream name, in bytes
890 * char stream_name[]; // Stream name in UTF-16LE, @stream_name_len bytes long,
891 * not including null terminator
892 * u16 zero; // UTF-16 null terminator for the stream name, NOT
893 * included in @stream_name_len. Based on what
894 * I've observed from filenames in dentries,
895 * this field should not exist when
896 * (@stream_name_len == 0), but you can't
897 * actually tell because of the padding anyway
898 * (provided that the padding is zeroed, which
899 * it always seems to be).
900 * char padding[]; // Padding to make the size a multiple of 8 bytes.
903 * In addition, the entries are 8-byte aligned.
905 * Return 0 on success or nonzero on failure. On success, dentry->ads_entries
906 * is set to an array of `struct ads_entry's of length dentry->num_ads. On
907 * failure, @dentry is not modified.
909 static int read_ads_entries(const u8 *p, struct dentry *dentry,
913 struct ads_entry *ads_entries;
916 num_ads = dentry->num_ads;
917 ads_entries = CALLOC(num_ads, sizeof(struct ads_entry));
919 ERROR("Could not allocate memory for %"PRIu16" "
920 "alternate data stream entries", num_ads);
921 return WIMLIB_ERR_NOMEM;
924 for (u16 i = 0; i < num_ads; i++) {
925 struct ads_entry *cur_entry = &ads_entries[i];
927 u64 length_no_padding;
930 const char *p_save = p;
932 /* Read the base stream entry, excluding the stream name. */
933 if (remaining_size < WIM_ADS_ENTRY_DISK_SIZE) {
934 ERROR("Stream entries go past end of metadata resource");
935 ERROR("(remaining_size = %"PRIu64")", remaining_size);
936 ret = WIMLIB_ERR_INVALID_DENTRY;
937 goto out_free_ads_entries;
940 p = get_u64(p, &length);
941 p += 8; /* Skip the reserved field */
942 p = get_bytes(p, SHA1_HASH_SIZE, (u8*)cur_entry->hash);
943 p = get_u16(p, &cur_entry->stream_name_len);
945 cur_entry->stream_name = NULL;
946 cur_entry->stream_name_utf8 = NULL;
948 /* Length including neither the null terminator nor the padding
950 length_no_padding = WIM_ADS_ENTRY_DISK_SIZE +
951 cur_entry->stream_name_len;
953 /* Length including the null terminator and the padding */
954 total_length = ((length_no_padding + 2) + 7) & ~7;
956 wimlib_assert(total_length == ads_entry_total_length(cur_entry));
958 if (remaining_size < length_no_padding) {
959 ERROR("Stream entries go past end of metadata resource");
960 ERROR("(remaining_size = %"PRIu64" bytes, "
961 "length_no_padding = %"PRIu16" bytes)",
962 remaining_size, length_no_padding);
963 ret = WIMLIB_ERR_INVALID_DENTRY;
964 goto out_free_ads_entries;
967 /* The @length field in the on-disk ADS entry is expected to be
968 * equal to @total_length, which includes all of the entry and
969 * the padding that follows it to align the next ADS entry to an
970 * 8-byte boundary. However, to be safe, we'll accept the
971 * length field as long as it's not less than the un-padded
972 * total length and not more than the padded total length. */
973 if (length < length_no_padding || length > total_length) {
974 ERROR("Stream entry has unexpected length "
975 "field (length field = %"PRIu64", "
976 "unpadded total length = %"PRIu64", "
977 "padded total length = %"PRIu64")",
978 length, length_no_padding, total_length);
979 ret = WIMLIB_ERR_INVALID_DENTRY;
980 goto out_free_ads_entries;
983 if (cur_entry->stream_name_len) {
984 cur_entry->stream_name = MALLOC(cur_entry->stream_name_len);
985 if (!cur_entry->stream_name) {
986 ret = WIMLIB_ERR_NOMEM;
987 goto out_free_ads_entries;
989 get_bytes(p, cur_entry->stream_name_len,
990 (u8*)cur_entry->stream_name);
991 cur_entry->stream_name_utf8 = utf16_to_utf8(cur_entry->stream_name,
992 cur_entry->stream_name_len,
994 cur_entry->stream_name_utf8_len = utf8_len;
996 if (!cur_entry->stream_name_utf8) {
997 ret = WIMLIB_ERR_NOMEM;
998 goto out_free_ads_entries;
1001 /* It's expected that the size of every ADS entry is a multiple
1002 * of 8. However, to be safe, I'm allowing the possibility of
1003 * an ADS entry at the very end of the metadata resource ending
1004 * un-aligned. So although we still need to increment the input
1005 * pointer by @total_length to reach the next ADS entry, it's
1006 * possible that less than @total_length is actually remaining
1007 * in the metadata resource. We should set the remaining size to
1008 * 0 bytes if this happens. */
1009 p = p_save + total_length;
1010 if (remaining_size < total_length)
1013 remaining_size -= total_length;
1015 dentry->ads_entries = ads_entries;
1017 out_free_ads_entries:
1018 for (u16 i = 0; i < num_ads; i++) {
1019 FREE(ads_entries[i].stream_name);
1020 FREE(ads_entries[i].stream_name_utf8);
1027 * Reads a directory entry, including all alternate data stream entries that
1028 * follow it, from the WIM image's metadata resource.
1030 * @metadata_resource: Buffer containing the uncompressed metadata resource.
1031 * @metadata_resource_len: Length of the metadata resource.
1032 * @offset: Offset of this directory entry in the metadata resource.
1033 * @dentry: A `struct dentry' that will be filled in by this function.
1035 * Return 0 on success or nonzero on failure. On failure, @dentry have been
1036 * modified, bu it will be left with no pointers to any allocated buffers.
1037 * On success, the dentry->length field must be examined. If zero, this was a
1038 * special "end of directory" dentry and not a real dentry. If nonzero, this
1039 * was a real dentry.
1041 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len,
1042 u64 offset, struct dentry *dentry)
1045 u64 calculated_size;
1046 char *file_name = NULL;
1047 char *file_name_utf8 = NULL;
1048 char *short_name = NULL;
1051 size_t file_name_utf8_len;
1054 dentry_common_init(dentry);
1056 /*Make sure the dentry really fits into the metadata resource.*/
1057 if (offset + 8 > metadata_resource_len || offset + 8 < offset) {
1058 ERROR("Directory entry starting at %"PRIu64" ends past the "
1059 "end of the metadata resource (size %"PRIu64")",
1060 offset, metadata_resource_len);
1061 return WIMLIB_ERR_INVALID_DENTRY;
1064 /* Before reading the whole dentry, we need to read just the length.
1065 * This is because a dentry of length 8 (that is, just the length field)
1066 * terminates the list of sibling directory entries. */
1068 p = get_u64(&metadata_resource[offset], &dentry->length);
1070 /* A zero length field (really a length of 8, since that's how big the
1071 * directory entry is...) indicates that this is the end of directory
1072 * dentry. We do not read it into memory as an actual dentry, so just
1073 * return successfully in that case. */
1074 if (dentry->length == 0)
1077 /* If the dentry does not overflow the metadata resource buffer and is
1078 * not too short, read the rest of it (excluding the alternate data
1079 * streams, but including the file name and short name variable-length
1080 * fields) into memory. */
1081 if (offset + dentry->length >= metadata_resource_len
1082 || offset + dentry->length < offset)
1084 ERROR("Directory entry at offset %"PRIu64" and with size "
1085 "%"PRIu64" ends past the end of the metadata resource "
1087 offset, dentry->length, metadata_resource_len);
1088 return WIMLIB_ERR_INVALID_DENTRY;
1091 if (dentry->length < WIM_DENTRY_DISK_SIZE) {
1092 ERROR("Directory entry has invalid length of %"PRIu64" bytes",
1094 return WIMLIB_ERR_INVALID_DENTRY;
1097 p = get_u32(p, &dentry->attributes);
1098 p = get_u32(p, (u32*)&dentry->security_id);
1099 p = get_u64(p, &dentry->subdir_offset);
1101 /* 2 unused fields */
1102 p += 2 * sizeof(u64);
1103 /*p = get_u64(p, &dentry->unused1);*/
1104 /*p = get_u64(p, &dentry->unused2);*/
1106 p = get_u64(p, &dentry->creation_time);
1107 p = get_u64(p, &dentry->last_access_time);
1108 p = get_u64(p, &dentry->last_write_time);
1110 p = get_bytes(p, SHA1_HASH_SIZE, dentry->hash);
1113 * I don't know what's going on here. It seems like M$ screwed up the
1114 * reparse points, then put the fields in the same place and didn't
1115 * document it. The WIM_HDR_FLAG_RP_FIX flag in the WIM header might
1116 * have something to do with this, but it's not documented.
1118 if (dentry->attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
1121 p = get_u32(p, &dentry->reparse_tag);
1124 p = get_u32(p, &dentry->reparse_tag);
1125 p = get_u64(p, &dentry->hard_link);
1128 /* By the way, the reparse_reserved field does not actually exist (at
1129 * least when the file is not a reparse point) */
1131 p = get_u16(p, &dentry->num_ads);
1133 p = get_u16(p, &short_name_len);
1134 p = get_u16(p, &file_name_len);
1136 /* We now know the length of the file name and short name. Make sure
1137 * the length of the dentry is large enough to actually hold them.
1139 * The calculated length here is unaligned to allow for the possibility
1140 * that the dentry->length names an unaligned length, although this
1141 * would be unexpected. */
1142 calculated_size = __dentry_correct_length_unaligned(file_name_len,
1145 if (dentry->length < calculated_size) {
1146 ERROR("Unexpected end of directory entry! (Expected "
1147 "at least %"PRIu64" bytes, got %"PRIu64" bytes. "
1148 "short_name_len = %hu, file_name_len = %hu)",
1149 calculated_size, dentry->length,
1150 short_name_len, file_name_len);
1151 return WIMLIB_ERR_INVALID_DENTRY;
1154 /* Read the filename if present. Note: if the filename is empty, there
1155 * is no null terminator following it. */
1156 if (file_name_len) {
1157 file_name = MALLOC(file_name_len);
1159 ERROR("Failed to allocate %hu bytes for dentry file name",
1161 return WIMLIB_ERR_NOMEM;
1163 p = get_bytes(p, file_name_len, file_name);
1165 /* Convert filename to UTF-8. */
1166 file_name_utf8 = utf16_to_utf8(file_name, file_name_len,
1167 &file_name_utf8_len);
1169 if (!file_name_utf8) {
1170 ERROR("Failed to allocate memory to convert UTF-16 "
1171 "filename (%hu bytes) to UTF-8", file_name_len);
1172 ret = WIMLIB_ERR_NOMEM;
1173 goto out_free_file_name;
1176 WARNING("Expected two zero bytes following the file name "
1177 "`%s', but found non-zero bytes", file_name_utf8);
1181 /* Align the calculated size */
1182 calculated_size = (calculated_size + 7) & ~7;
1184 if (dentry->length > calculated_size) {
1185 /* Weird; the dentry says it's longer than it should be. Note
1186 * that the length field does NOT include the size of the
1187 * alternate stream entries. */
1189 /* Strangely, some directory entries inexplicably have a little
1190 * over 70 bytes of extra data. The exact amount of data seems
1191 * to be 72 bytes, but it is aligned on the next 8-byte
1192 * boundary. It does NOT seem to be alternate data stream
1193 * entries. Here's an example of the aligned data:
1195 * 01000000 40000000 6c786bba c58ede11 b0bb0026 1870892a b6adb76f
1196 * e63a3e46 8fca8653 0d2effa1 6c786bba c58ede11 b0bb0026 1870892a
1197 * 00000000 00000000 00000000 00000000
1199 * Here's one interpretation of how the data is laid out.
1202 * u32 field1; (always 0x00000001)
1203 * u32 field2; (always 0x40000000)
1204 * u8 data[48]; (???)
1205 * u64 reserved1; (always 0)
1206 * u64 reserved2; (always 0)
1208 WARNING("Dentry for file or directory `%s' has %zu extra "
1210 file_name_utf8, dentry->length - calculated_size);
1213 /* Read the short filename if present. Note: if there is no short
1214 * filename, there is no null terminator following it. */
1215 if (short_name_len) {
1216 short_name = MALLOC(short_name_len);
1218 ERROR("Failed to allocate %hu bytes for short filename",
1220 ret = WIMLIB_ERR_NOMEM;
1221 goto out_free_file_name_utf8;
1224 p = get_bytes(p, short_name_len, short_name);
1226 WARNING("Expected two zero bytes following the file name "
1227 "`%s', but found non-zero bytes", file_name_utf8);
1232 * Read the alternate data streams, if present. dentry->num_ads tells
1233 * us how many they are, and they will directly follow the dentry
1236 * Note that each alternate data stream entry begins on an 8-byte
1237 * aligned boundary, and the alternate data stream entries are NOT
1238 * included in the dentry->length field for some reason.
1240 if (dentry->num_ads != 0) {
1241 if (calculated_size > metadata_resource_len - offset) {
1242 ERROR("Not enough space in metadata resource for "
1243 "alternate stream entries");
1244 ret = WIMLIB_ERR_INVALID_DENTRY;
1245 goto out_free_short_name;
1247 ret = read_ads_entries(&metadata_resource[offset + calculated_size],
1249 metadata_resource_len - offset - calculated_size);
1251 goto out_free_short_name;
1254 /* We've read all the data for this dentry. Set the names and their
1255 * lengths, and we've done. */
1256 dentry->file_name = file_name;
1257 dentry->file_name_utf8 = file_name_utf8;
1258 dentry->short_name = short_name;
1259 dentry->file_name_len = file_name_len;
1260 dentry->file_name_utf8_len = file_name_utf8_len;
1261 dentry->short_name_len = short_name_len;
1263 out_free_short_name:
1265 out_free_file_name_utf8:
1266 FREE(file_name_utf8);
1272 /* Run some miscellaneous verifications on a WIM dentry */
1273 int verify_dentry(struct dentry *dentry, void *wim)
1275 const WIMStruct *w = wim;
1276 const struct lookup_table *table = w->lookup_table;
1277 const struct wim_security_data *sd = wim_const_security_data(w);
1278 int ret = WIMLIB_ERR_INVALID_DENTRY;
1280 /* Check the security ID */
1281 if (dentry->security_id < -1) {
1282 ERROR("Dentry `%s' has an invalid security ID (%d)",
1283 dentry->full_path_utf8, dentry->security_id);
1286 if (dentry->security_id >= sd->num_entries) {
1287 ERROR("Dentry `%s' has an invalid security ID (%d) "
1288 "(there are only %u entries in the security table)",
1289 dentry->full_path_utf8, dentry->security_id,
1294 /* Check that lookup table entries for all the resources exist, except
1295 * if the SHA1 message digest is all 0's, which indicates there is
1296 * intentionally no resource there. */
1297 if (w->hdr.total_parts == 1) {
1298 for (unsigned i = 0; i <= dentry->num_ads; i++) {
1299 struct lookup_table_entry *lte;
1301 hash = dentry_stream_hash_unresolved(dentry, i);
1302 lte = __lookup_resource(table, hash);
1303 if (!lte && !is_zero_hash(hash)) {
1304 ERROR("Could not find lookup table entry for stream "
1305 "%u of dentry `%s'", i, dentry->full_path_utf8);
1311 /* Make sure there is only one un-named stream. */
1312 unsigned num_unnamed_streams = 0;
1313 unsigned unnamed_stream_idx;
1314 for (unsigned i = 0; i <= dentry->num_ads; i++) {
1316 hash = dentry_stream_hash_unresolved(dentry, i);
1317 if (!dentry_stream_name_len(dentry, i) && !is_zero_hash(hash)) {
1318 num_unnamed_streams++;
1319 unnamed_stream_idx = i;
1322 if (num_unnamed_streams > 1) {
1323 ERROR("Dentry `%s' has multiple (%u) un-named streams",
1324 dentry->full_path_utf8, num_unnamed_streams);
1329 /* Check timestamps */
1330 if (dentry->last_access_time < dentry->creation_time ||
1331 dentry->last_write_time < dentry->creation_time) {
1332 WARNING("Dentry `%s' was created after it was last accessed or "
1333 "written to", dentry->full_path_utf8);
1343 * Writes a WIM dentry to an output buffer.
1345 * @dentry: The dentry structure.
1346 * @p: The memory location to write the data to.
1347 * @return: Pointer to the byte after the last byte we wrote as part of the
1350 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
1356 /* We calculate the correct length of the dentry ourselves because the
1357 * dentry->length field may been set to an unexpected value from when we
1358 * read the dentry in (for example, there may have been unknown data
1359 * appended to the end of the dentry...) */
1360 u64 length = dentry_correct_length(dentry);
1362 p = put_u64(p, length);
1363 p = put_u32(p, dentry->attributes);
1364 p = put_u32(p, dentry->security_id);
1365 p = put_u64(p, dentry->subdir_offset);
1366 p = put_u64(p, 0); /* unused1 */
1367 p = put_u64(p, 0); /* unused2 */
1368 p = put_u64(p, dentry->creation_time);
1369 p = put_u64(p, dentry->last_access_time);
1370 p = put_u64(p, dentry->last_write_time);
1371 if (dentry->resolved && dentry->lte)
1372 hash = dentry->lte->hash;
1374 hash = dentry->hash;
1375 p = put_bytes(p, SHA1_HASH_SIZE, hash);
1376 if (dentry->attributes & FILE_ATTRIBUTE_REPARSE_POINT) {
1377 p = put_zeroes(p, 4);
1378 p = put_u32(p, dentry->reparse_tag);
1379 p = put_zeroes(p, 4);
1383 if (dentry->link_group_list.next == &dentry->link_group_list)
1386 hard_link = dentry->hard_link;
1387 p = put_u64(p, hard_link);
1389 p = put_u16(p, dentry->num_ads);
1390 p = put_u16(p, dentry->short_name_len);
1391 p = put_u16(p, dentry->file_name_len);
1392 if (dentry->file_name_len) {
1393 p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
1394 p = put_u16(p, 0); /* filename padding, 2 bytes. */
1396 if (dentry->short_name) {
1397 p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
1398 p = put_u16(p, 0); /* short name padding, 2 bytes */
1401 /* Align to 8-byte boundary */
1402 wimlib_assert(length >= (p - orig_p)
1403 && length - (p - orig_p) <= 7);
1404 p = put_zeroes(p, length - (p - orig_p));
1406 /* Write the alternate data streams, if there are any. Please see
1407 * read_ads_entries() for comments about the format of the on-disk
1408 * alternate data stream entries. */
1409 for (u16 i = 0; i < dentry->num_ads; i++) {
1410 p = put_u64(p, ads_entry_total_length(&dentry->ads_entries[i]));
1411 p = put_u64(p, 0); /* Unused */
1412 if (dentry->resolved && dentry->ads_entries[i].lte)
1413 hash = dentry->ads_entries[i].lte->hash;
1415 hash = dentry->ads_entries[i].hash;
1416 p = put_bytes(p, SHA1_HASH_SIZE, hash);
1417 p = put_u16(p, dentry->ads_entries[i].stream_name_len);
1418 if (dentry->ads_entries[i].stream_name_len) {
1419 p = put_bytes(p, dentry->ads_entries[i].stream_name_len,
1420 (u8*)dentry->ads_entries[i].stream_name);
1423 p = put_zeroes(p, (8 - (p - orig_p) % 8) % 8);
1425 #ifdef ENABLE_ASSERTIONS
1426 wimlib_assert(p - orig_p == __dentry_total_length(dentry, length));
1431 /* Recursive function that writes a dentry tree rooted at @parent, not including
1432 * @parent itself, which has already been written. */
1433 static u8 *write_dentry_tree_recursive(const struct dentry *parent, u8 *p)
1435 const struct dentry *child;
1437 /* Nothing to do if this dentry has no children. */
1438 if (parent->subdir_offset == 0)
1441 /* Write child dentries and end-of-directory entry.
1443 * Note: we need to write all of this dentry's children before
1444 * recursively writing the directory trees rooted at each of the child
1445 * dentries, since the on-disk dentries for a dentry's children are
1446 * always located at consecutive positions in the metadata resource! */
1447 child = parent->children;
1450 p = write_dentry(child, p);
1451 child = child->next;
1452 } while (child != parent->children);
1455 /* write end of directory entry */
1458 /* Recurse on children. */
1461 p = write_dentry_tree_recursive(child, p);
1462 child = child->next;
1463 } while (child != parent->children);
1468 /* Writes a directory tree to the metadata resource.
1470 * @root: Root of the dentry tree.
1471 * @p: Pointer to a buffer with enough space for the dentry tree.
1473 * Returns pointer to the byte after the last byte we wrote.
1475 u8 *write_dentry_tree(const struct dentry *root, u8 *p)
1477 wimlib_assert(dentry_is_root(root));
1479 /* If we're the root dentry, we have no parent that already
1480 * wrote us, so we need to write ourselves. */
1481 p = write_dentry(root, p);
1483 /* Write end of directory entry after the root dentry just to be safe;
1484 * however the root dentry obviously cannot have any siblings. */
1487 /* Recursively write the rest of the dentry tree. */
1488 return write_dentry_tree_recursive(root, p);
1491 /* Reads the children of a dentry, and all their children, ..., etc. from the
1492 * metadata resource and into the dentry tree.
1494 * @metadata_resource: An array that contains the uncompressed metadata
1495 * resource for the WIM file.
1497 * @metadata_resource_len: The length of the uncompressed metadata resource, in
1500 * @dentry: A pointer to a `struct dentry' that is the root of the directory
1501 * tree and has already been read from the metadata resource. It
1502 * does not need to be the real root because this procedure is
1503 * called recursively.
1505 * @return: Zero on success, nonzero on failure.
1507 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
1508 struct dentry *dentry)
1510 u64 cur_offset = dentry->subdir_offset;
1511 struct dentry *prev_child = NULL;
1512 struct dentry *first_child = NULL;
1513 struct dentry *child;
1514 struct dentry cur_child;
1518 * If @dentry has no child dentries, nothing more needs to be done for
1519 * this branch. This is the case for regular files, symbolic links, and
1520 * *possibly* empty directories (although an empty directory may also
1521 * have one child dentry that is the special end-of-directory dentry)
1523 if (cur_offset == 0)
1526 /* Find and read all the children of @dentry. */
1529 /* Read next child of @dentry into @cur_child. */
1530 ret = read_dentry(metadata_resource, metadata_resource_len,
1531 cur_offset, &cur_child);
1535 /* Check for end of directory. */
1536 if (cur_child.length == 0)
1539 /* Not end of directory. Allocate this child permanently and
1540 * link it to the parent and previous child. */
1541 child = MALLOC(sizeof(struct dentry));
1543 ERROR("Failed to allocate %zu bytes for new dentry",
1544 sizeof(struct dentry));
1545 ret = WIMLIB_ERR_NOMEM;
1548 memcpy(child, &cur_child, sizeof(struct dentry));
1551 prev_child->next = child;
1552 child->prev = prev_child;
1554 first_child = child;
1557 child->parent = dentry;
1560 /* If there are children of this child, call this procedure
1562 if (child->subdir_offset != 0) {
1563 ret = read_dentry_tree(metadata_resource,
1564 metadata_resource_len, child);
1569 /* Advance to the offset of the next child. Note: We need to
1570 * advance by the TOTAL length of the dentry, not by the length
1571 * child->length, which although it does take into account the
1572 * padding, it DOES NOT take into account alternate stream
1574 cur_offset += dentry_total_length(child);
1577 /* Link last child to first one, and set parent's children pointer to
1578 * the first child. */
1580 prev_child->next = first_child;
1581 first_child->prev = prev_child;
1583 dentry->children = first_child;