print named file attribute flags in wimlib_print_dentry()
[wimlib] / src / dentry.c
1 /*
2  * dentry.c
3  *
4  * A dentry (directory entry) contains the metadata for a file.  In the WIM file
5  * format, the dentries are stored in the "metadata resource" section right
6  * after the security data.  Each image in the WIM file has its own metadata
7  * resource with its own security data and dentry tree.  Dentries in different
8  * images may share file resources by referring to the same lookup table
9  * entries.
10  */
11
12 /*
13  *
14  * Copyright (C) 2010 Carl Thijssen
15  * Copyright (C) 2012 Eric Biggers
16  *
17  * This file is part of wimlib, a library for working with WIM files.
18  *
19  * wimlib is free software; you can redistribute it and/or modify it under the
20  * terms of the GNU Lesser General Public License as published by the Free
21  * Software Foundation; either version 2.1 of the License, or (at your option)
22  * any later version.
23  *
24  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
25  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
26  * A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
27  * details.
28  *
29  * You should have received a copy of the GNU Lesser General Public License
30  * along with wimlib; if not, see http://www.gnu.org/licenses/.
31  */
32
33 #include "wimlib_internal.h"
34 #include "dentry.h"
35 #include "io.h"
36 #include "timestamp.h"
37 #include "lookup_table.h"
38 #include "sha1.h"
39 #include <unistd.h>
40 #include <sys/stat.h>
41
42
43 /* Transfers file attributes from a `stat' buffer to a struct dentry. */
44 void stbuf_to_dentry(const struct stat *stbuf, struct dentry *dentry)
45 {
46         if (S_ISDIR(stbuf->st_mode))
47                 dentry->attributes = WIM_FILE_ATTRIBUTE_DIRECTORY;
48         else
49                 dentry->attributes = WIM_FILE_ATTRIBUTE_NORMAL;
50 }
51
52 /* Transfers file attributes from a struct dentry to a `stat' buffer. */
53 void dentry_to_stbuf(const struct dentry *dentry, struct stat *stbuf, 
54                      const struct lookup_table *table)
55 {
56         struct lookup_table_entry *lte;
57
58         if (dentry_is_directory(dentry))
59                 stbuf->st_mode = S_IFDIR | 0755;
60         else
61                 stbuf->st_mode = S_IFREG | 0644;
62
63         if (table)
64                 lte = lookup_resource(table, dentry->hash);
65         else
66                 lte = NULL;
67
68         if (lte) {
69                 stbuf->st_nlink = lte->refcnt;
70                 stbuf->st_size = lte->resource_entry.original_size;
71         } else {
72                 stbuf->st_nlink = 1;
73                 stbuf->st_size = 0;
74         }
75         stbuf->st_uid     = getuid();
76         stbuf->st_gid     = getgid();
77         stbuf->st_atime   = ms_timestamp_to_unix(dentry->last_access_time);
78         stbuf->st_mtime   = ms_timestamp_to_unix(dentry->last_write_time);
79         stbuf->st_ctime   = ms_timestamp_to_unix(dentry->creation_time);
80         stbuf->st_blocks  = (stbuf->st_size + 511) / 512;
81 }
82
83 /* Makes all timestamp fields for the dentry be the current time. */
84 void dentry_update_all_timestamps(struct dentry *dentry)
85 {
86         u64 now = get_timestamp();
87         dentry->creation_time    = now;
88         dentry->last_access_time = now;
89         dentry->last_write_time  = now;
90 }
91
92 /* 
93  * Calls a function on all directory entries in a directory tree.  It is called
94  * on a parent before its children.
95  */
96 int for_dentry_in_tree(struct dentry *root, 
97                        int (*visitor)(struct dentry*, void*), void *arg)
98 {
99         int ret;
100         struct dentry *child;
101
102         ret = visitor(root, arg);
103
104         if (ret != 0)
105                 return ret;
106
107         child = root->children;
108
109         if (!child)
110                 return 0;
111
112         do {
113                 ret = for_dentry_in_tree(child, visitor, arg);
114                 if (ret != 0)
115                         return ret;
116                 child = child->next;
117         } while (child != root->children);
118         return 0;
119 }
120
121 /* 
122  * Like for_dentry_in_tree(), but the visitor function is always called on a
123  * dentry's children before on itself.
124  */
125 int for_dentry_in_tree_depth(struct dentry *root, 
126                              int (*visitor)(struct dentry*, void*), void *arg)
127 {
128         int ret;
129         struct dentry *child;
130         struct dentry *next;
131
132         child = root->children;
133         if (child) {
134                 do {
135                         next = child->next;
136                         ret = for_dentry_in_tree_depth(child, visitor, arg);
137                         if (ret != 0)
138                                 return ret;
139                         child = next;
140                 } while (child != root->children);
141         }
142         return visitor(root, arg);
143 }
144
145 /* 
146  * Calculate the full path of @dentry, based on its parent's full path and on
147  * its UTF-8 file name. 
148  */
149 int calculate_dentry_full_path(struct dentry *dentry, void *ignore)
150 {
151         char *full_path;
152         u32 full_path_len;
153         if (dentry_is_root(dentry)) {
154                 full_path = MALLOC(2);
155                 if (!full_path)
156                         goto oom;
157                 full_path[0] = '/';
158                 full_path[1] = '\0';
159                 full_path_len = 1;
160         } else {
161                 char *parent_full_path;
162                 u32 parent_full_path_len;
163                 const struct dentry *parent = dentry->parent;
164
165                 if (dentry_is_root(parent)) {
166                         parent_full_path = "";
167                         parent_full_path_len = 0;
168                 } else {
169                         parent_full_path = parent->full_path_utf8;
170                         parent_full_path_len = parent->full_path_utf8_len;
171                 }
172
173                 full_path_len = parent_full_path_len + 1 +
174                                 dentry->file_name_utf8_len;
175                 full_path = MALLOC(full_path_len + 1);
176                 if (!full_path)
177                         goto oom;
178
179                 memcpy(full_path, parent_full_path, parent_full_path_len);
180                 full_path[parent_full_path_len] = '/';
181                 memcpy(full_path + parent_full_path_len + 1,
182                        dentry->file_name_utf8,
183                        dentry->file_name_utf8_len);
184                 full_path[full_path_len] = '\0';
185         }
186         FREE(dentry->full_path_utf8);
187         dentry->full_path_utf8 = full_path;
188         dentry->full_path_utf8_len = full_path_len;
189         return 0;
190 oom:
191         ERROR("Out of memory while calculating dentry full path");
192         return WIMLIB_ERR_NOMEM;
193 }
194
195 /* 
196  * Recursively calculates the subdir offsets for a directory tree. 
197  *
198  * @dentry:  The root of the directory tree.
199  * @subdir_offset_p:  The current subdirectory offset; i.e., the subdirectory
200  *      offset for @dentry. 
201  */
202 void calculate_subdir_offsets(struct dentry *dentry, u64 *subdir_offset_p)
203 {
204         struct dentry *child;
205
206         child = dentry->children;
207         dentry->subdir_offset = *subdir_offset_p;
208         if (child) {
209
210                 /* Advance the subdir offset by the amount of space the children
211                  * of this dentry take up. */
212                 do {
213                         *subdir_offset_p += child->length;
214                         child = child->next;
215                 } while (child != dentry->children);
216
217                 /* End-of-directory dentry on disk. */
218                 *subdir_offset_p += 8;
219
220                 /* Recursively call calculate_subdir_offsets() on all the
221                  * children. */
222                 do {
223                         calculate_subdir_offsets(child, subdir_offset_p);
224                         child = child->next;
225                 } while (child != dentry->children);
226         } else {
227                 /* On disk, childless directories have a valid subdir_offset
228                  * that points to an 8-byte end-of-directory dentry.  Regular
229                  * files have a subdir_offset of 0. */
230                 if (dentry_is_directory(dentry))
231                         *subdir_offset_p += 8;
232                 else
233                         dentry->subdir_offset = 0;
234         }
235 }
236
237
238 /* Returns the child of @dentry that has the file name @name.  
239  * Returns NULL if no child has the name. */
240 struct dentry *get_dentry_child_with_name(const struct dentry *dentry, 
241                                                         const char *name)
242 {
243         struct dentry *child;
244         size_t name_len;
245         
246         child = dentry->children;
247         if (child) {
248                 name_len = strlen(name);
249                 do {
250                         if (dentry_has_name(child, name, name_len))
251                                 return child;
252                         child = child->next;
253                 } while (child != dentry->children);
254         }
255         return NULL;
256 }
257
258 /* Retrieves the dentry that has the UTF-8 @path relative to the dentry
259  * @cur_dir.  Returns NULL if no dentry having the path is found. */
260 static struct dentry *get_dentry_relative_path(struct dentry *cur_dir, const char *path)
261 {
262         struct dentry *child;
263         size_t base_len;
264         const char *new_path;
265
266         if (*path == '\0')
267                 return cur_dir;
268
269         child = cur_dir->children;
270         if (child) {
271                 new_path = path_next_part(path, &base_len);
272                 do {
273                         if (dentry_has_name(child, path, base_len))
274                                 return get_dentry_relative_path(child, new_path);
275                         child = child->next;
276                 } while (child != cur_dir->children);
277         }
278         return NULL;
279 }
280
281 /* Returns the dentry corresponding to the UTF-8 @path, or NULL if there is no
282  * such dentry. */
283 struct dentry *get_dentry(WIMStruct *w, const char *path)
284 {
285         struct dentry *root = wim_root_dentry(w);
286         while (*path == '/')
287                 path++;
288         return get_dentry_relative_path(root, path);
289 }
290
291 /* Returns the parent directory for the @path. */
292 struct dentry *get_parent_dentry(WIMStruct *w, const char *path)
293 {
294         size_t path_len = strlen(path);
295         char buf[path_len + 1];
296
297         memcpy(buf, path, path_len + 1);
298
299         to_parent_name(buf, path_len);
300
301         return get_dentry(w, buf);
302 }
303
304 /* Prints the full path of a dentry. */
305 int print_dentry_full_path(struct dentry *dentry, void *ignore)
306 {
307         if (dentry->full_path_utf8)
308                 puts(dentry->full_path_utf8);
309         return 0;
310 }
311
312 struct file_attr_flag {
313         u32 flag;
314         const char *name;
315 };
316 struct file_attr_flag file_attr_flags[] = {
317         {WIM_FILE_ATTRIBUTE_READONLY,           "READONLY"},
318         {WIM_FILE_ATTRIBUTE_HIDDEN,             "HIDDEN"},
319         {WIM_FILE_ATTRIBUTE_SYSTEM,             "SYSTEM"},
320         {WIM_FILE_ATTRIBUTE_DIRECTORY,          "DIRECTORY"},
321         {WIM_FILE_ATTRIBUTE_ARCHIVE,            "ARCHIVE"},
322         {WIM_FILE_ATTRIBUTE_DEVICE,             "DEVICE"},
323         {WIM_FILE_ATTRIBUTE_NORMAL,             "NORMAL"},
324         {WIM_FILE_ATTRIBUTE_TEMPORARY,          "TEMPORARY"},
325         {WIM_FILE_ATTRIBUTE_SPARSE_FILE,        "SPARSE_FILE"},
326         {WIM_FILE_ATTRIBUTE_REPARSE_POINT,      "REPARSE_POINT"},
327         {WIM_FILE_ATTRIBUTE_COMPRESSED,         "COMPRESSED"},
328         {WIM_FILE_ATTRIBUTE_OFFLINE,            "OFFLINE"},
329         {WIM_FILE_ATTRIBUTE_NOT_CONTENT_INDEXED,"NOT_CONTENT_INDEXED"},
330         {WIM_FILE_ATTRIBUTE_ENCRYPTED,          "ENCRYPTED"},
331         {WIM_FILE_ATTRIBUTE_VIRTUAL,            "VIRTUAL"},
332 };
333
334 /* Prints a directory entry.  @lookup_table is a pointer to the lookup table, or
335  * NULL if the resource entry for the dentry is not to be printed. */
336 int print_dentry(struct dentry *dentry, void *lookup_table)
337 {
338         struct lookup_table_entry *lte;
339         unsigned i;
340
341         printf("[DENTRY]\n");
342         printf("Length            = %"PRIu64"\n", dentry->length);
343         printf("Attributes        = 0x%x\n", dentry->attributes);
344         for (i = 0; i < ARRAY_LEN(file_attr_flags); i++)
345                 if (file_attr_flags[i].flag & dentry->attributes)
346                         printf("    WIM_FILE_ATTRIBUTE_%s is set\n",
347                                 file_attr_flags[i].name);
348 #ifdef ENABLE_SECURITY_DATA
349         printf("Security ID       = %d\n", dentry->security_id);
350 #endif
351         printf("Subdir offset     = %"PRIu64"\n", dentry->subdir_offset);
352         /*printf("Unused1           = %"PRIu64"\n", dentry->unused1);*/
353         /*printf("Unused2           = %"PRIu64"\n", dentry->unused2);*/
354         printf("Creation Time     = %"PRIu64"\n", dentry->creation_time);
355         printf("Last Access Time  = %"PRIu64"\n", dentry->last_access_time);
356         printf("Last Write Time   = %"PRIu64"\n", dentry->last_write_time);
357         printf("Creation Time     = 0x%"PRIx64"\n", dentry->creation_time);
358         printf("Hash              = "); 
359         print_hash(dentry->hash); 
360         putchar('\n');
361         /*printf("Reparse Tag       = %u\n", dentry->reparse_tag);*/
362         printf("Hard Link Group   = %"PRIu64"\n", dentry->hard_link);
363         /*printf("Number of Streams = %hu\n", dentry->streams);*/
364         printf("Filename          = \"");
365         print_string(dentry->file_name, dentry->file_name_len);
366         puts("\"");
367         printf("Filename Length   = %hu\n", dentry->file_name_len);
368         printf("Filename (UTF-8)  = \"%s\"\n", dentry->file_name_utf8);
369         printf("Filename (UTF-8) Length = %hu\n", dentry->file_name_utf8_len);
370         printf("Short Name        = \"");
371         print_string(dentry->short_name, dentry->short_name_len);
372         puts("\"");
373         printf("Short Name Length = %hu\n", dentry->short_name_len);
374         printf("Full Path (UTF-8) = \"%s\"\n", dentry->full_path_utf8);
375         if (lookup_table) {
376                 lte = lookup_resource(lookup_table, dentry->hash);
377                 if (lte)
378                         print_lookup_table_entry(lte, NULL);
379                 else
380                         putchar('\n');
381         } else {
382                 putchar('\n');
383         }
384         return 0;
385 }
386
387 static inline void dentry_common_init(struct dentry *dentry)
388 {
389         memset(dentry, 0, sizeof(struct dentry));
390         dentry->refcnt = 1;
391 }
392
393 /* 
394  * Creates an unlinked directory entry.
395  *
396  * @name:    The base name of the new dentry.
397  * @return:  A pointer to the new dentry, or NULL if out of memory.
398  */
399 struct dentry *new_dentry(const char *name)
400 {
401         struct dentry *dentry;
402         
403         dentry = MALLOC(sizeof(struct dentry));
404         if (!dentry)
405                 return NULL;
406
407         dentry_common_init(dentry);
408         if (change_dentry_name(dentry, name) != 0) {
409                 FREE(dentry);
410                 return NULL;
411         }
412
413         dentry_update_all_timestamps(dentry);
414         dentry->next   = dentry;
415         dentry->prev   = dentry;
416         dentry->parent = dentry;
417         return dentry;
418 }
419
420
421 void free_dentry(struct dentry *dentry)
422 {
423         FREE(dentry->file_name);
424         FREE(dentry->file_name_utf8);
425         FREE(dentry->short_name);
426         FREE(dentry->full_path_utf8);
427         FREE(dentry);
428 }
429
430 /* Arguments for do_free_dentry(). */
431 struct free_dentry_args {
432         struct lookup_table *lookup_table;
433         bool lt_decrement_refcnt;
434 };
435
436 /* 
437  * This function is passed as an argument to for_dentry_in_tree_depth() in order
438  * to free a directory tree.  __args is a pointer to a `struct free_dentry_args'.
439  */
440 static int do_free_dentry(struct dentry *dentry, void *__args)
441 {
442         struct free_dentry_args *args = (struct free_dentry_args*)__args;
443
444         if (args->lt_decrement_refcnt && !dentry_is_directory(dentry)) {
445                 lookup_table_decrement_refcnt(args->lookup_table, 
446                                               dentry->hash);
447         }
448
449         wimlib_assert(dentry->refcnt >= 1);
450         if (--dentry->refcnt == 0)
451                 free_dentry(dentry);
452         return 0;
453 }
454
455 /* 
456  * Unlinks and frees a dentry tree.
457  *
458  * @root:               The root of the tree.
459  * @lookup_table:       The lookup table for dentries.
460  * @decrement_refcnt:   True if the dentries in the tree are to have their 
461  *                      reference counts in the lookup table decremented.
462  */
463 void free_dentry_tree(struct dentry *root, struct lookup_table *lookup_table, 
464                       bool lt_decrement_refcnt)
465 {
466         if (!root || !root->parent)
467                 return;
468
469         struct free_dentry_args args;
470         args.lookup_table        = lookup_table;
471         args.lt_decrement_refcnt = lt_decrement_refcnt;
472         for_dentry_in_tree_depth(root, do_free_dentry, &args);
473 }
474
475 int increment_dentry_refcnt(struct dentry *dentry, void *ignore)
476 {
477         dentry->refcnt++;
478         return 0;
479 }
480
481 /* 
482  * Links a dentry into the directory tree.
483  *
484  * @dentry: The dentry to link.
485  * @parent: The dentry that will be the parent of @dentry.
486  */
487 void link_dentry(struct dentry *dentry, struct dentry *parent)
488 {
489         dentry->parent = parent;
490         if (parent->children) {
491                 /* Not an only child; link to siblings. */
492                 dentry->next = parent->children;
493                 dentry->prev = parent->children->prev;
494                 dentry->next->prev = dentry;
495                 dentry->prev->next = dentry;
496         } else {
497                 /* Only child; link to parent. */
498                 parent->children = dentry;
499                 dentry->next = dentry;
500                 dentry->prev = dentry;
501         }
502 }
503
504 /* Unlink a dentry from the directory tree. */
505 void unlink_dentry(struct dentry *dentry)
506 {
507         if (dentry_is_root(dentry))
508                 return;
509         if (dentry_is_only_child(dentry)) {
510                 dentry->parent->children = NULL;
511         } else {
512                 if (dentry_is_first_sibling(dentry))
513                         dentry->parent->children = dentry->next;
514                 dentry->next->prev = dentry->prev;
515                 dentry->prev->next = dentry->next;
516         }
517 }
518
519
520 /* Recalculates the length of @dentry based on its file name length and short
521  * name length.  */
522 static inline void recalculate_dentry_size(struct dentry *dentry)
523 {
524         dentry->length = WIM_DENTRY_DISK_SIZE + dentry->file_name_len + 
525                          2 + dentry->short_name_len;
526         /* Must be multiple of 8. */
527         dentry->length += (8 - dentry->length % 8) % 8;
528 }
529
530 /* Changes the name of a dentry to @new_name.  Only changes the file_name and
531  * file_name_utf8 fields; does not change the short_name, short_name_utf8, or
532  * full_path_utf8 fields.  Also recalculates its length. */
533 int change_dentry_name(struct dentry *dentry, const char *new_name)
534 {
535         size_t utf8_len;
536         size_t utf16_len;
537
538         FREE(dentry->file_name);
539
540         utf8_len = strlen(new_name);
541
542         dentry->file_name = utf8_to_utf16(new_name, utf8_len, &utf16_len);
543
544         if (!dentry->file_name)
545                 return WIMLIB_ERR_NOMEM;
546
547         FREE(dentry->file_name_utf8);
548         dentry->file_name_utf8 = MALLOC(utf8_len + 1);
549         if (!dentry->file_name_utf8) {
550                 FREE(dentry->file_name);
551                 dentry->file_name = NULL;
552                 return WIMLIB_ERR_NOMEM;
553         }
554
555         dentry->file_name_len = utf16_len;
556         dentry->file_name_utf8_len = utf8_len;
557         memcpy(dentry->file_name_utf8, new_name, utf8_len + 1);
558         recalculate_dentry_size(dentry);
559         return 0;
560 }
561
562 /* Parameters for calculate_dentry_statistics(). */
563 struct image_statistics {
564         struct lookup_table *lookup_table;
565         u64 *dir_count;
566         u64 *file_count;
567         u64 *total_bytes;
568         u64 *hard_link_bytes;
569 };
570
571 static int calculate_dentry_statistics(struct dentry *dentry, void *arg)
572 {
573         struct image_statistics *stats;
574         struct lookup_table_entry *lte; 
575         
576         stats = arg;
577         lte = lookup_resource(stats->lookup_table, dentry->hash);
578
579         if (dentry_is_directory(dentry) && !dentry_is_root(dentry))
580                 ++*stats->dir_count;
581         else
582                 ++*stats->file_count;
583
584         if (lte) {
585                 u64 size = lte->resource_entry.original_size;
586                 *stats->total_bytes += size;
587                 if (++lte->out_refcnt == 1)
588                         *stats->hard_link_bytes += size;
589         }
590         return 0;
591 }
592
593 void calculate_dir_tree_statistics(struct dentry *root, struct lookup_table *table, 
594                                    u64 *dir_count_ret, u64 *file_count_ret, 
595                                    u64 *total_bytes_ret, 
596                                    u64 *hard_link_bytes_ret)
597 {
598         struct image_statistics stats;
599         *dir_count_ret         = 0;
600         *file_count_ret        = 0;
601         *total_bytes_ret       = 0;
602         *hard_link_bytes_ret   = 0;
603         stats.lookup_table     = table;
604         stats.dir_count       = dir_count_ret;
605         stats.file_count      = file_count_ret;
606         stats.total_bytes     = total_bytes_ret;
607         stats.hard_link_bytes = hard_link_bytes_ret;
608         for_lookup_table_entry(table, zero_out_refcnts, NULL);
609         for_dentry_in_tree(root, calculate_dentry_statistics, &stats);
610 }
611
612 /* 
613  * Reads a directory entry from the metadata resource.
614  */
615 int read_dentry(const u8 metadata_resource[], u64 metadata_resource_len, 
616                 u64 offset, struct dentry *dentry)
617 {
618         const u8 *p;
619         u64 calculated_size;
620         char *file_name;
621         char *file_name_utf8;
622         char *short_name;
623         u16 short_name_len;
624         u16 file_name_len;
625         size_t file_name_utf8_len;
626
627         dentry_common_init(dentry);
628
629         /*Make sure the dentry really fits into the metadata resource.*/
630         if (offset + 8 > metadata_resource_len) {
631                 ERROR("Directory entry starting at %"PRIu64" ends past the "
632                       "end of the metadata resource (size %"PRIu64")",
633                       offset, metadata_resource_len);
634                 return WIMLIB_ERR_INVALID_DENTRY;
635         }
636
637         /* Before reading the whole entry, we need to read just the length.
638          * This is because an entry of length 8 (that is, just the length field)
639          * terminates the list of sibling directory entries. */
640
641         p = get_u64(&metadata_resource[offset], &dentry->length);
642
643         /* A zero length field (really a length of 8, since that's how big the
644          * directory entry is...) indicates that this is the end of directory
645          * dentry.  We do not read it into memory as an actual dentry, so just
646          * return true in that case. */
647         if (dentry->length == 0)
648                 return 0;
649
650         if (offset + dentry->length >= metadata_resource_len) {
651                 ERROR("Directory entry at offset %"PRIu64" and with size "
652                       "%"PRIu64" ends past the end of the metadata resource "
653                       "(size %"PRIu64")",
654                       offset, dentry->length, metadata_resource_len);
655                 return WIMLIB_ERR_INVALID_DENTRY;
656         }
657
658         /* If it is a recognized length, read the rest of the directory entry.
659          * Note: The root directory entry has no name, and its length does not
660          * include the short name length field.  */
661         if (dentry->length < WIM_DENTRY_DISK_SIZE) {
662                 ERROR("Directory entry has invalid length of %"PRIu64" bytes",
663                       dentry->length);
664                 return WIMLIB_ERR_INVALID_DENTRY;
665         }
666
667         p = get_u32(p, &dentry->attributes);
668 #ifdef ENABLE_SECURITY_DATA
669         p = get_u32(p, (u32*)&dentry->security_id);
670 #else
671         p += sizeof(u32);
672 #endif
673         p = get_u64(p, &dentry->subdir_offset);
674
675         /* 2 unused fields */
676         p += 2 * sizeof(u64);
677
678         p = get_u64(p, &dentry->creation_time);
679         p = get_u64(p, &dentry->last_access_time);
680         p = get_u64(p, &dentry->last_write_time);
681
682         p = get_bytes(p, WIM_HASH_SIZE, dentry->hash);
683         
684         /* Currently ignoring reparse_tag. */
685         p += sizeof(u32);
686
687         /* The reparse_reserved field does not actually exist. */
688
689         p = get_u64(p, &dentry->hard_link);
690         
691         /* Currently ignoring streams. */
692         p += sizeof(u16);
693
694         p = get_u16(p, &short_name_len);
695         p = get_u16(p, &file_name_len);
696
697         calculated_size = WIM_DENTRY_DISK_SIZE + file_name_len + 2 +
698                           short_name_len;
699
700         if (dentry->length < calculated_size) {
701                 ERROR("Unexpected end of directory entry! (Expected "
702                       "%"PRIu64" bytes, got %"PRIu64" bytes. "
703                       "short_name_len = %hu, file_name_len = %hu)", 
704                       calculated_size, dentry->length,
705                       short_name_len, file_name_len);
706                 return WIMLIB_ERR_INVALID_DENTRY;
707         }
708
709         /* Read the filename. */
710         file_name = MALLOC(file_name_len);
711         if (!file_name) {
712                 ERROR("Failed to allocate %hu bytes for dentry file name",
713                       file_name_len);
714                 return WIMLIB_ERR_NOMEM;
715         }
716         p = get_bytes(p, file_name_len, file_name);
717
718         /* Convert filename to UTF-8. */
719         file_name_utf8 = utf16_to_utf8(file_name, file_name_len, 
720                                        &file_name_utf8_len);
721
722         if (!file_name_utf8) {
723                 ERROR("Failed to allocate memory to convert UTF-16 "
724                       "filename (%hu bytes) to UTF-8", file_name_len);
725                 goto out_free_file_name;
726         }
727
728         /* Undocumented padding between file name and short name.  This probably
729          * is supposed to be a terminating null character. */
730         p += 2;
731
732         /* Read the short filename. */
733         short_name = MALLOC(short_name_len);
734         if (!short_name) {
735                 ERROR("Failed to allocate %hu bytes for short filename",
736                       short_name_len);
737                 goto out_free_file_name_utf8;
738         }
739
740         get_bytes(p, short_name_len, short_name);
741
742         dentry->file_name          = file_name;
743         dentry->file_name_utf8     = file_name_utf8;
744         dentry->short_name         = short_name;
745         dentry->file_name_len      = file_name_len;
746         dentry->file_name_utf8_len = file_name_utf8_len;
747         dentry->short_name_len     = short_name_len;
748         return 0;
749 out_free_file_name_utf8:
750         FREE(dentry->file_name_utf8);
751 out_free_file_name:
752         FREE(dentry->file_name);
753         return WIMLIB_ERR_NOMEM;
754 }
755
756 /* 
757  * Writes a dentry to an output buffer.
758  *
759  * @dentry:  The dentry structure.
760  * @p:       The memory location to write the data to.
761  * @return:  True on success, false on failure.
762  */
763 static u8 *write_dentry(const struct dentry *dentry, u8 *p)
764 {
765         u8 *orig_p = p;
766         memset(p, 0, dentry->length);
767         p = put_u64(p, dentry->length);
768         p = put_u32(p, dentry->attributes);
769 #ifdef ENABLE_SECURITY_DATA
770         p = put_u32(p, dentry->security_id);
771 #else
772         p = put_u32(p, (u32)(-1));
773 #endif
774         p = put_u64(p, dentry->subdir_offset);
775         p = put_u64(p, 0); /* unused1 */
776         p = put_u64(p, 0); /* unused2 */
777         p = put_u64(p, dentry->creation_time);
778         p = put_u64(p, dentry->last_access_time);
779         p = put_u64(p, dentry->last_write_time);
780         if (!is_empty_file_hash(dentry->hash))
781                 memcpy(p, dentry->hash, WIM_HASH_SIZE);
782         else
783                 DEBUG("zero hash for %s\n", dentry->file_name_utf8);
784         p += WIM_HASH_SIZE;
785         p = put_u32(p, 0); /* reparse_tag */
786         p = put_u64(p, dentry->hard_link);
787         p = put_u16(p, 0); /*streams */
788         p = put_u16(p, dentry->short_name_len);
789         p = put_u16(p, dentry->file_name_len);
790         p = put_bytes(p, dentry->file_name_len, (u8*)dentry->file_name);
791         p = put_u16(p, 0); /* filename padding, 2 bytes. */
792         p = put_bytes(p, dentry->short_name_len, (u8*)dentry->short_name);
793         return orig_p + dentry->length;
794 }
795
796 /* Recursive function that writes a dentry tree rooted at @tree, not including
797  * @tree itself, which has already been written, except in the case of the root
798  * dentry, which is written right away, along with an end-of-directory entry. */
799 u8 *write_dentry_tree(const struct dentry *tree, u8 *p)
800 {
801         const struct dentry *child;
802
803         if (dentry_is_root(tree)) {
804                 p = write_dentry(tree, p);
805
806                 /* write end of directory entry */
807                 p = put_u64(p, 0);
808         } else {
809                 /* Nothing to do for a regular file. */
810                 if (dentry_is_regular_file(tree))
811                         return p;
812         }
813
814         /* Write child dentries and end-of-directory entry. */
815         child = tree->children;
816         if (child) {
817                 do {
818                         p = write_dentry(child, p);
819                         child = child->next;
820                 } while (child != tree->children);
821         }
822
823         /* write end of directory entry */
824         p = put_u64(p, 0);
825
826         /* Recurse on children. */
827         if (child) {
828                 do {
829                         p = write_dentry_tree(child, p);
830                         child = child->next;
831                 } while (child != tree->children);
832         }
833         return p;
834 }
835
836 /* Reads the children of a dentry, and all their children, ..., etc. from the
837  * metadata resource and into the dentry tree.
838  *
839  * @metadata_resource:  An array that contains the uncompressed metadata
840  *                      resource for the WIM file.
841  * @metadata_resource_len:      The length of @metadata_resource.
842  * @dentry:     A pointer to a struct dentry that is the root of the directory
843  *              tree and has already been read from the metadata resource.  It
844  *              does not need to be the real root because this procedure is
845  *              called recursively.
846  *
847  * @return:     Zero on success, nonzero on failure.
848  */
849 int read_dentry_tree(const u8 metadata_resource[], u64 metadata_resource_len,
850                      struct dentry *dentry)
851 {
852         u64 cur_offset = dentry->subdir_offset;
853         struct dentry *prev_child = NULL;
854         struct dentry *first_child = NULL;
855         struct dentry *child;
856         struct dentry cur_child;
857         int ret;
858
859         /* If @dentry is a regular file, nothing more needs to be done for this
860          * branch. */
861         if (cur_offset == 0)
862                 return 0;
863
864         /* Find and read all the children of @dentry. */
865         while (1) {
866
867                 /* Read next child of @dentry into @cur_child. */
868                 ret = read_dentry(metadata_resource, metadata_resource_len, 
869                                   cur_offset, &cur_child);
870                 if (ret != 0)
871                         break;
872
873                 /* Check for end of directory. */
874                 if (cur_child.length == 0) {
875                         ret = 0;
876                         break;
877                 }
878
879                 /* Not end of directory.  Allocate this child permanently and
880                  * link it to the parent and previous child. */
881                 child = MALLOC(sizeof(struct dentry));
882                 if (!child) {
883                         ERROR("Failed to allocate %zu bytes for new dentry",
884                               sizeof(struct dentry));
885                         ret = WIMLIB_ERR_NOMEM;
886                         break;
887                 }
888                 memcpy(child, &cur_child, sizeof(struct dentry));
889
890                 if (prev_child) {
891                         prev_child->next = child;
892                         child->prev = prev_child;
893                 } else {
894                         first_child = child;
895                 }
896
897                 child->parent = dentry;
898                 prev_child = child;
899
900                 /* If there are children of this child, call this procedure
901                  * recursively. */
902                 if (child->subdir_offset != 0) {
903                         ret = read_dentry_tree(metadata_resource, 
904                                                metadata_resource_len, child);
905                         if (ret != 0)
906                                 break;
907                 }
908
909                 /* Advance to the offset of the next child. */
910                 cur_offset += child->length;
911         }
912
913         /* Link last child to first one, and set parent's
914          * children pointer to the first child.  */
915         if (prev_child) {
916                 prev_child->next = first_child;
917                 first_child->prev = prev_child;
918         }
919         dentry->children = first_child;
920         return ret;
921 }