Implement advisory locking for WIM overwrites
[wimlib] / src / wim.c
1 /*
2  * wim.c
3  */
4
5 /*
6  * Copyright (C) 2010 Carl Thijssen
7  * Copyright (C) 2012 Eric Biggers
8  *
9  * wimlib - Library for working with WIM files
10  *
11  * This file is part of wimlib, a library for working with WIM files.
12  *
13  * wimlib is free software; you can redistribute it and/or modify it under the
14  * terms of the GNU General Public License as published by the Free
15  * Software Foundation; either version 3 of the License, or (at your option)
16  * any later version.
17  *
18  * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
19  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
20  * A PARTICULAR PURPOSE. See the GNU General Public License for more
21  * details.
22  *
23  * You should have received a copy of the GNU General Public License
24  * along with wimlib; if not, see http://www.gnu.org/licenses/.
25  */
26
27 #include "config.h"
28 #include <limits.h>
29 #include <stdlib.h>
30 #include <stdarg.h>
31
32 #include "dentry.h"
33 #include <unistd.h>
34 #include <fcntl.h>
35
36 #ifdef WITH_NTFS_3G
37 #include <time.h>
38 #include <ntfs-3g/volume.h>
39 #endif
40
41 #include "wimlib_internal.h"
42 #include "io.h"
43 #include "lookup_table.h"
44 #include "xml.h"
45
46 static int print_metadata(WIMStruct *w)
47 {
48         DEBUG("Printing metadata for image %d", w->current_image);
49         print_security_data(wim_security_data(w));
50         return for_dentry_in_tree(wim_root_dentry(w), print_dentry,
51                                   w->lookup_table);
52 }
53
54
55 static int print_files(WIMStruct *w)
56 {
57         return for_dentry_in_tree(wim_root_dentry(w), print_dentry_full_path,
58                                   NULL);
59 }
60
61 WIMStruct *new_wim_struct()
62 {
63         WIMStruct *w = CALLOC(1, sizeof(WIMStruct));
64 #ifdef WITH_FUSE
65         if (pthread_mutex_init(&w->fp_tab_mutex, NULL) != 0) {
66                 ERROR_WITH_ERRNO("Failed to initialize mutex");
67                 FREE(w);
68                 w = NULL;
69         }
70 #endif
71         return w;
72
73 }
74
75 /*
76  * Calls a function on images in the WIM.  If @image is WIMLIB_ALL_IMAGES, @visitor
77  * is called on the WIM once for each image, with each image selected as the
78  * current image in turn.  If @image is a certain image, @visitor is called on
79  * the WIM only once, with that image selected.
80  */
81 int for_image(WIMStruct *w, int image, int (*visitor)(WIMStruct *))
82 {
83         int ret;
84         int start;
85         int end;
86         int i;
87
88         if (image == WIMLIB_ALL_IMAGES) {
89                 start = 1;
90                 end = w->hdr.image_count;
91         } else if (image >= 1 && image <= w->hdr.image_count) {
92                 start = image;
93                 end = image;
94         } else {
95                 return WIMLIB_ERR_INVALID_IMAGE;
96         }
97         for (i = start; i <= end; i++) {
98                 ret = select_wim_image(w, i);
99                 if (ret != 0)
100                         return ret;
101                 ret = visitor(w);
102                 if (ret != 0)
103                         return ret;
104         }
105         return 0;
106 }
107
108 static int sort_image_metadata_by_position(const void *p1, const void *p2)
109 {
110         const struct image_metadata *imd1 = p1;
111         const struct image_metadata *imd2 = p2;
112         u64 offset1 = imd1->metadata_lte->resource_entry.offset;
113         u64 offset2 = imd2->metadata_lte->resource_entry.offset;
114         if (offset1 < offset2)
115                 return -1;
116         else if (offset1 > offset2)
117                 return 1;
118         else
119                 return 0;
120 }
121
122 /*
123  * If @lte points to a metadata resource, append it to the list of metadata
124  * resources in the WIMStruct.  Otherwise, do nothing.
125  */
126 static int append_metadata_resource_entry(struct lookup_table_entry *lte,
127                                           void *wim_p)
128 {
129         WIMStruct *w = wim_p;
130         int ret = 0;
131
132         if (lte->resource_entry.flags & WIM_RESHDR_FLAG_METADATA) {
133                 if (w->current_image == w->hdr.image_count) {
134                         ERROR("The WIM header says there are %u images in the WIM,\n"
135                               "        but we found more metadata resources than this",
136                               w->hdr.image_count);
137                         ret = WIMLIB_ERR_IMAGE_COUNT;
138                 } else {
139                         DEBUG("Found metadata resource for image %u at "
140                               "offset %"PRIu64".",
141                               w->current_image + 1,
142                               lte->resource_entry.offset);
143                         w->image_metadata[
144                                 w->current_image++].metadata_lte = lte;
145                 }
146         }
147         return ret;
148 }
149
150 /* Returns the compression type given in the flags of a WIM header. */
151 int wim_hdr_flags_compression_type(int wim_hdr_flags)
152 {
153         if (wim_hdr_flags & WIM_HDR_FLAG_COMPRESSION) {
154                 if (wim_hdr_flags & WIM_HDR_FLAG_COMPRESS_LZX)
155                         return WIMLIB_COMPRESSION_TYPE_LZX;
156                 else if (wim_hdr_flags & WIM_HDR_FLAG_COMPRESS_XPRESS)
157                         return WIMLIB_COMPRESSION_TYPE_XPRESS;
158                 else
159                         return WIMLIB_COMPRESSION_TYPE_INVALID;
160         } else {
161                 return WIMLIB_COMPRESSION_TYPE_NONE;
162         }
163 }
164
165 /*
166  * Creates a WIMStruct for a new WIM file.
167  */
168 WIMLIBAPI int wimlib_create_new_wim(int ctype, WIMStruct **w_ret)
169 {
170         WIMStruct *w;
171         struct lookup_table *table;
172         int ret;
173
174         DEBUG("Creating new WIM with %s compression.",
175               wimlib_get_compression_type_string(ctype));
176
177         /* Allocate the WIMStruct. */
178         w = new_wim_struct();
179         if (!w)
180                 return WIMLIB_ERR_NOMEM;
181
182         ret = init_header(&w->hdr, ctype);
183         if (ret != 0)
184                 goto out_free;
185
186         table = new_lookup_table(9001);
187         if (!table) {
188                 ret = WIMLIB_ERR_NOMEM;
189                 goto out_free;
190         }
191         w->lookup_table = table;
192         *w_ret = w;
193         return 0;
194 out_free:
195         FREE(w);
196         return ret;
197 }
198
199 WIMLIBAPI int wimlib_get_num_images(const WIMStruct *w)
200 {
201         return w->hdr.image_count;
202 }
203
204 int select_wim_image(WIMStruct *w, int image)
205 {
206         struct image_metadata *imd;
207
208         DEBUG("Selecting image %d", image);
209
210         if (image == w->current_image)
211                 return 0;
212
213         if (image < 1 || image > w->hdr.image_count) {
214                 ERROR("Cannot select image %d: There are only %u images",
215                       image, w->hdr.image_count);
216                 return WIMLIB_ERR_INVALID_IMAGE;
217         }
218
219         /* If a valid image is currently selected, it can be freed if it is not
220          * modified.  */
221         if (w->current_image != WIMLIB_NO_IMAGE) {
222                 imd = wim_get_current_image_metadata(w);
223                 if (!imd->modified) {
224                         DEBUG("Freeing image %u", w->current_image);
225                         destroy_image_metadata(imd, NULL);
226                         imd->root_dentry = NULL;
227                         imd->security_data = NULL;
228                 }
229         }
230
231         w->current_image = image;
232         imd = wim_get_current_image_metadata(w);
233
234         if (imd->root_dentry) {
235                 return 0;
236         } else {
237                 #ifdef ENABLE_DEBUG
238                 DEBUG("Reading metadata resource specified by the following "
239                       "lookup table entry:");
240                 print_lookup_table_entry(imd->metadata_lte);
241                 #endif
242                 return read_metadata_resource(w, imd);
243         }
244 }
245
246
247 /* Returns the compression type of the WIM file. */
248 WIMLIBAPI int wimlib_get_compression_type(const WIMStruct *w)
249 {
250         return wim_hdr_flags_compression_type(w->hdr.flags);
251 }
252
253 WIMLIBAPI const char *wimlib_get_compression_type_string(int ctype)
254 {
255         switch (ctype) {
256                 case WIMLIB_COMPRESSION_TYPE_NONE:
257                         return "None";
258                 case WIMLIB_COMPRESSION_TYPE_LZX:
259                         return "LZX";
260                 case WIMLIB_COMPRESSION_TYPE_XPRESS:
261                         return "XPRESS";
262                 default:
263                         return "Invalid";
264         }
265 }
266
267 /*
268  * Returns the number of an image in the WIM file, given a string that is either
269  * the number of the image, or the name of the image.  The images are numbered
270  * starting at 1.
271  */
272 WIMLIBAPI int wimlib_resolve_image(WIMStruct *w, const char *image_name_or_num)
273 {
274         char *p;
275         int image;
276         int i;
277
278         if (!image_name_or_num || !*image_name_or_num)
279                 return WIMLIB_NO_IMAGE;
280
281         if (strcmp(image_name_or_num, "all") == 0
282             || strcmp(image_name_or_num, "*") == 0)
283                 return WIMLIB_ALL_IMAGES;
284         image = strtol(image_name_or_num, &p, 10);
285         if (p != image_name_or_num && *p == '\0' && image > 0) {
286                 if (image > w->hdr.image_count)
287                         return WIMLIB_NO_IMAGE;
288                 return image;
289         } else {
290                 for (i = 1; i <= w->hdr.image_count; i++) {
291                         if (strcmp(image_name_or_num,
292                                    wimlib_get_image_name(w, i)) == 0)
293                                 return i;
294                 }
295                 return WIMLIB_NO_IMAGE;
296         }
297 }
298
299
300 /* Prints some basic information about a WIM file. */
301 WIMLIBAPI void wimlib_print_wim_information(const WIMStruct *w)
302 {
303         const struct wim_header *hdr;
304
305         hdr = &w->hdr;
306         puts("WIM Information:");
307         puts("----------------");
308         printf("Path:           %s\n", w->filename);
309         fputs ("GUID:           0x", stdout);
310         print_byte_field(hdr->guid, WIM_GID_LEN);
311         putchar('\n');
312         printf("Image Count:    %d\n", hdr->image_count);
313         printf("Compression:    %s\n", wimlib_get_compression_type_string(
314                                                 wimlib_get_compression_type(w)));
315         printf("Part Number:    %d/%d\n", hdr->part_number, hdr->total_parts);
316         printf("Boot Index:     %d\n", hdr->boot_idx);
317         printf("Size:           %"PRIu64" bytes\n",
318                                 wim_info_get_total_bytes(w->wim_info));
319         printf("Integrity Info: %s\n", (w->hdr.integrity.size != 0) ? "yes" : "no");
320         putchar('\n');
321 }
322
323 WIMLIBAPI bool wimlib_has_integrity_table(const WIMStruct *w)
324 {
325         return w->hdr.integrity.size != 0;
326 }
327
328 WIMLIBAPI void wimlib_print_available_images(const WIMStruct *w, int image)
329 {
330         int first;
331         int last;
332         int i;
333         int n;
334         if (image == WIMLIB_ALL_IMAGES) {
335                 n = printf("Available Images:\n");
336                 first = 1;
337                 last = w->hdr.image_count;
338         } else if (image >= 1 && image <= w->hdr.image_count) {
339                 n = printf("Information for Image %d\n", image);
340                 first = image;
341                 last = image;
342         } else {
343                 printf("wimlib_print_available_images(): Invalid image %d",
344                        image);
345                 return;
346         }
347         for (i = 0; i < n - 1; i++)
348                 putchar('-');
349         putchar('\n');
350         for (i = first; i <= last; i++)
351                 print_image_info(w->wim_info, i);
352 }
353
354
355 /* Prints the metadata for the specified image, which may be WIMLIB_ALL_IMAGES, but
356  * not WIMLIB_NO_IMAGE. */
357 WIMLIBAPI int wimlib_print_metadata(WIMStruct *w, int image)
358 {
359         if (!w)
360                 return WIMLIB_ERR_INVALID_PARAM;
361         if (w->hdr.part_number != 1) {
362                 ERROR("Cannot show the metadata from part %hu of a %hu-part split WIM!",
363                        w->hdr.part_number, w->hdr.total_parts);
364                 ERROR("Select the first part of the split WIM to see the metadata.");
365                 return WIMLIB_ERR_SPLIT_UNSUPPORTED;
366         }
367         return for_image(w, image, print_metadata);
368 }
369
370 WIMLIBAPI int wimlib_print_files(WIMStruct *w, int image)
371 {
372         if (!w)
373                 return WIMLIB_ERR_INVALID_PARAM;
374         if (w->hdr.part_number != 1) {
375                 ERROR("Cannot list the files from part %hu of a %hu-part split WIM!",
376                        w->hdr.part_number, w->hdr.total_parts);
377                 ERROR("Select the first part of the split WIM if you'd like to list the files.");
378                 return WIMLIB_ERR_SPLIT_UNSUPPORTED;
379         }
380         return for_image(w, image, print_files);
381 }
382
383 /* Sets the index of the bootable image. */
384 WIMLIBAPI int wimlib_set_boot_idx(WIMStruct *w, int boot_idx)
385 {
386         if (!w)
387                 return WIMLIB_ERR_INVALID_PARAM;
388         if (w->hdr.total_parts != 1) {
389                 ERROR("Cannot modify the boot index of a split WIM!");
390                 return WIMLIB_ERR_SPLIT_UNSUPPORTED;
391         }
392         if (boot_idx < 0 || boot_idx > w->hdr.image_count)
393                 return WIMLIB_ERR_INVALID_IMAGE;
394         w->hdr.boot_idx = boot_idx;
395
396         if (boot_idx == 0) {
397                 memset(&w->hdr.boot_metadata_res_entry, 0,
398                        sizeof(struct resource_entry));
399         } else {
400                 memcpy(&w->hdr.boot_metadata_res_entry,
401                        &w->image_metadata[
402                           boot_idx - 1].metadata_lte->resource_entry,
403                        sizeof(struct resource_entry));
404         }
405
406         return 0;
407 }
408
409 WIMLIBAPI int wimlib_get_part_number(const WIMStruct *w, int *total_parts_ret)
410 {
411         if (total_parts_ret)
412                 *total_parts_ret = w->hdr.total_parts;
413         return w->hdr.part_number;
414 }
415
416
417 WIMLIBAPI int wimlib_get_boot_idx(const WIMStruct *w)
418 {
419         return w->hdr.boot_idx;
420 }
421
422 /* Opens a WIM readable */
423 static int open_wim_readable(WIMStruct *w, const char *path)
424 {
425         if (w->fp != NULL)
426                 fclose(w->fp);
427         wimlib_assert(path != NULL);
428         w->fp = fopen(path, "rb");
429         if (!w->fp) {
430                 ERROR_WITH_ERRNO("Failed to open `%s' for reading",
431                                  path);
432                 return WIMLIB_ERR_OPEN;
433         }
434         return 0;
435 }
436
437 /*
438  * Begins the reading of a WIM file; opens the file and reads its header and
439  * lookup table, and optionally checks the integrity.
440  */
441 static int begin_read(WIMStruct *w, const char *in_wim_path, int open_flags,
442                       wimlib_progress_func_t progress_func)
443 {
444         int ret;
445         uint xml_num_images;
446
447         DEBUG("Reading the WIM file `%s'", in_wim_path);
448
449         ret = open_wim_readable(w, in_wim_path);
450         if (ret != 0)
451                 goto out;
452
453         w->filename = realpath(in_wim_path, NULL);
454         if (!w->filename) {
455                 ERROR_WITH_ERRNO("Failed to resolve WIM filename");
456                 ret = WIMLIB_ERR_NOMEM;
457                 goto out_close;
458         }
459
460         ret = read_header(w->fp, &w->hdr, open_flags);
461         if (ret != 0)
462                 goto out_close;
463
464         DEBUG("Wim file contains %u images", w->hdr.image_count);
465
466         /* If the boot index is invalid, print a warning and set it to 0 */
467         if (w->hdr.boot_idx > w->hdr.image_count) {
468                 WARNING("In `%s', image %u is marked as bootable, "
469                         "but there are only %u images in the WIM",
470                         in_wim_path, w->hdr.boot_idx, w->hdr.image_count);
471                 w->hdr.boot_idx = 0;
472         }
473
474         if (wimlib_get_compression_type(w) == WIMLIB_COMPRESSION_TYPE_INVALID) {
475                 ERROR("Invalid compression type (WIM header flags = %x)",
476                       w->hdr.flags);
477                 ret = WIMLIB_ERR_INVALID_COMPRESSION_TYPE;
478                 goto out_close;
479         }
480
481         if (open_flags & WIMLIB_OPEN_FLAG_CHECK_INTEGRITY) {
482                 ret = check_wim_integrity(w, progress_func);
483                 if (ret == WIM_INTEGRITY_NONEXISTENT) {
484                         WARNING("No integrity information for `%s'; skipping "
485                                 "integrity check.", w->filename);
486                 } else if (ret == WIM_INTEGRITY_NOT_OK) {
487                         ERROR("WIM is not intact! (Failed integrity check)");
488                         ret = WIMLIB_ERR_INTEGRITY;
489                         goto out_close;
490                 } else if (ret != 0) {
491                         goto out_close;
492                 }
493         }
494
495         if (resource_is_compressed(&w->hdr.lookup_table_res_entry)) {
496                 ERROR("Didn't expect a compressed lookup table!");
497                 ERROR("Ask the author to implement support for this.");
498                 ret = WIMLIB_ERR_COMPRESSED_LOOKUP_TABLE;
499                 goto out_close;
500         }
501
502         ret = read_lookup_table(w);
503         if (ret != 0)
504                 goto out_close;
505
506         w->image_metadata = CALLOC(w->hdr.image_count,
507                                    sizeof(struct image_metadata));
508
509         if (!w->image_metadata) {
510                 ERROR("Failed to allocate memory for %u metadata structures",
511                       w->hdr.image_count);
512                 ret = WIMLIB_ERR_NOMEM;
513                 goto out_free_lookup_table;
514         }
515         w->current_image = 0;
516
517         DEBUG("Looking for metadata resources in the lookup table.");
518
519         /* Find the images in the WIM by searching the lookup table. */
520         ret = for_lookup_table_entry(w->lookup_table,
521                                      append_metadata_resource_entry, w);
522
523         if (ret != 0)
524                 goto out_free_image_metadata;
525
526         /* Make sure all the expected images were found.  (We already have
527          * returned false if *extra* images were found) */
528         if (w->current_image != w->hdr.image_count &&
529             w->hdr.part_number == 1)
530         {
531                 ERROR("Only found %u images in WIM, but expected %u",
532                       w->current_image, w->hdr.image_count);
533                 ret = WIMLIB_ERR_IMAGE_COUNT;
534                 goto out_free_image_metadata;
535         }
536
537         /* Sort images by the position of their metadata resources.  I'm
538          * assuming that is what determines the other of the images in the WIM
539          * file, rather than their order in the lookup table, which is random
540          * because of hashing. */
541         qsort(w->image_metadata, w->current_image,
542               sizeof(struct image_metadata), sort_image_metadata_by_position);
543
544         w->current_image = WIMLIB_NO_IMAGE;
545
546         /* Read the XML data. */
547         ret = read_xml_data(w->fp, &w->hdr.xml_res_entry,
548                             &w->xml_data, &w->wim_info);
549
550         if (ret != 0)
551                 goto out_free_image_metadata;
552
553         xml_num_images = wim_info_get_num_images(w->wim_info);
554         if (xml_num_images != w->hdr.image_count) {
555                 ERROR("In the file `%s', there are %u <IMAGE> elements "
556                       "in the XML data,", in_wim_path, xml_num_images);
557                 ERROR("but %u images in the WIM!  There must be exactly one "
558                       "<IMAGE> element per image.", w->hdr.image_count);
559                 ret = WIMLIB_ERR_IMAGE_COUNT;
560                 goto out_free_xml_data;
561         }
562
563         DEBUG("Done beginning read of WIM file `%s'.", in_wim_path);
564         return 0;
565
566         //
567         // Everything is freed in wimlib_free() anyway, so no need to roll back
568         // changes here.
569         //
570 out_free_xml_data:
571         /*FREE(w->xml_data);*/
572         /*w->xml_data = NULL;*/
573         /*free_wim_info(w->wim_info);*/
574         /*w->wim_info = NULL;*/
575 out_free_image_metadata:
576         /*FREE(w->image_metadata);*/
577         /*w->image_metadata = NULL;*/
578         /*w->current_image = WIMLIB_NO_IMAGE;*/
579 out_free_lookup_table:
580         /*free_lookup_table(w->lookup_table);*/
581         /*w->lookup_table = NULL;*/
582 out_close:
583         /*fclose(w->fp);*/
584         /*w->fp = NULL;*/
585 out:
586         return ret;
587 }
588
589
590 /*
591  * Opens a WIM file and creates a WIMStruct for it.
592  */
593 WIMLIBAPI int wimlib_open_wim(const char *wim_file, int open_flags,
594                               WIMStruct **w_ret,
595                               wimlib_progress_func_t progress_func)
596 {
597         WIMStruct *w;
598         int ret;
599
600         DEBUG("wim_file = `%s', open_flags = %#x", wim_file, open_flags);
601         w = new_wim_struct();
602         if (!w) {
603                 ERROR("Failed to allocate memory for WIMStruct");
604                 return WIMLIB_ERR_NOMEM;
605         }
606
607         ret = begin_read(w, wim_file, open_flags, progress_func);
608         if (ret == 0) {
609                 *w_ret = w;
610         } else {
611                 DEBUG("Could not begin reading the WIM file `%s'", wim_file);
612                 wimlib_free(w);
613         }
614         return ret;
615 }
616
617 /* Frees the memory for the WIMStruct, including all internal memory; also
618  * closes all files associated with the WIMStruct.  */
619 WIMLIBAPI void wimlib_free(WIMStruct *w)
620 {
621         DEBUG2("Freeing WIMStruct");
622
623         if (!w)
624                 return;
625         if (w->fp)
626                 fclose(w->fp);
627         if (w->out_fp)
628                 fclose(w->out_fp);
629
630 #ifdef WITH_FUSE
631         if (w->fp_tab) {
632                 for (size_t i = 0; i < w->num_allocated_fps; i++)
633                         if (w->fp_tab[i])
634                                 fclose(w->fp_tab[i]);
635                 FREE(w->fp_tab);
636         }
637         pthread_mutex_destroy(&w->fp_tab_mutex);
638 #endif
639
640         free_lookup_table(w->lookup_table);
641
642         FREE(w->filename);
643         FREE(w->xml_data);
644         free_wim_info(w->wim_info);
645         if (w->image_metadata) {
646                 for (uint i = 0; i < w->hdr.image_count; i++)
647                         destroy_image_metadata(&w->image_metadata[i], NULL);
648                 FREE(w->image_metadata);
649         }
650 #ifdef WITH_NTFS_3G
651         if (w->ntfs_vol) {
652                 DEBUG("Unmounting NTFS volume");
653                 ntfs_umount(w->ntfs_vol, FALSE);
654         }
655 #endif
656         FREE(w);
657 }