4 * Read uncompressed and compressed metadata and file resources.
8 * Copyright (C) 2010 Carl Thijssen
9 * Copyright (C) 2012 Eric Biggers
11 * This file is part of wimlib, a library for working with WIM files.
13 * wimlib is free software; you can redistribute it and/or modify it under the
14 * terms of the GNU Lesser General Public License as published by the Free
15 * Software Foundation; either version 2.1 of the License, or (at your option)
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 Lesser General Public License for more
23 * You should have received a copy of the GNU Lesser General Public License
24 * along with wimlib; if not, see http://www.gnu.org/licenses/.
27 #include "wimlib_internal.h"
28 #include "lookup_table.h"
40 #include <ntfs-3g/attrib.h>
41 #include <ntfs-3g/inode.h>
42 #include <ntfs-3g/dir.h>
46 * Reads all or part of a compressed resource into an in-memory buffer.
48 * @fp: The FILE* for the WIM file.
49 * @resource_compressed_size: The compressed size of the resource.
50 * @resource_uncompressed_size: The uncompressed size of the resource.
51 * @resource_offset: The offset of the start of the resource from
52 * the start of the stream @fp.
53 * @resource_ctype: The compression type of the resource.
54 * @len: The number of bytes of uncompressed data to read from
56 * @offset: The offset of the bytes to read within the uncompressed
58 * @contents_len: An array into which the uncompressed data is written.
59 * It must be at least @len bytes long.
61 * Returns zero on success, nonzero on failure.
63 static int read_compressed_resource(FILE *fp, u64 resource_compressed_size,
64 u64 resource_uncompressed_size,
65 u64 resource_offset, int resource_ctype,
66 u64 len, u64 offset, u8 contents_ret[])
69 DEBUG2("comp size = %"PRIu64", uncomp size = %"PRIu64", "
70 "res offset = %"PRIu64"",
71 resource_compressed_size,
72 resource_uncompressed_size,
74 DEBUG2("resource_ctype = %s, len = %"PRIu64", offset = %"PRIu64"",
75 wimlib_get_compression_type_string(resource_ctype), len, offset);
80 int (*decompress)(const void *, uint, void *, uint);
81 /* Set the appropriate decompress function. */
82 if (resource_ctype == WIM_COMPRESSION_TYPE_LZX)
83 decompress = lzx_decompress;
85 decompress = xpress_decompress;
87 /* The structure of a compressed resource consists of a table of chunk
88 * offsets followed by the chunks themselves. Each chunk consists of
89 * compressed data, and there is one chunk for each WIM_CHUNK_SIZE =
90 * 32768 bytes of the uncompressed file, with the last chunk having any
93 * The chunk offsets are measured relative to the end of the chunk
94 * table. The first chunk is omitted from the table in the WIM file
95 * because its offset is implicitly given by the fact that it directly
96 * follows the chunk table and therefore must have an offset of 0.
99 /* Calculate how many chunks the resource conists of in its entirety. */
100 u64 num_chunks = (resource_uncompressed_size + WIM_CHUNK_SIZE - 1) /
102 /* As mentioned, the first chunk has no entry in the chunk table. */
103 u64 num_chunk_entries = num_chunks - 1;
106 /* The index of the chunk that the read starts at. */
107 u64 start_chunk = offset / WIM_CHUNK_SIZE;
108 /* The byte offset at which the read starts, within the start chunk. */
109 u64 start_chunk_offset = offset % WIM_CHUNK_SIZE;
111 /* The index of the chunk that contains the last byte of the read. */
112 u64 end_chunk = (offset + len - 1) / WIM_CHUNK_SIZE;
113 /* The byte offset of the last byte of the read, within the end chunk */
114 u64 end_chunk_offset = (offset + len - 1) % WIM_CHUNK_SIZE;
116 /* Number of chunks that are actually needed to read the requested part
118 u64 num_needed_chunks = end_chunk - start_chunk + 1;
120 /* If the end chunk is not the last chunk, an extra chunk entry is
121 * needed because we need to know the offset of the chunk after the last
122 * chunk read to figure out the size of the last read chunk. */
123 if (end_chunk != num_chunks - 1)
126 /* Declare the chunk table. It will only contain offsets for the chunks
127 * that are actually needed for this read. */
128 u64 chunk_offsets[num_needed_chunks];
130 /* Set the implicit offset of the first chunk if it is included in the
133 * Note: M$'s documentation includes a picture that shows the first
134 * chunk starting right after the chunk entry table, labeled as offset
135 * 0x10. However, in the actual file format, the offset is measured
136 * from the end of the chunk entry table, so the first chunk has an
138 if (start_chunk == 0)
139 chunk_offsets[0] = 0;
141 /* According to M$'s documentation, if the uncompressed size of
142 * the file is greater than 4 GB, the chunk entries are 8-byte
143 * integers. Otherwise, they are 4-byte integers. */
144 u64 chunk_entry_size = (resource_uncompressed_size >= (u64)1 << 32) ?
147 /* Size of the full chunk table in the WIM file. */
148 u64 chunk_table_size = chunk_entry_size * num_chunk_entries;
150 /* Read the needed chunk offsets from the table in the WIM file. */
152 /* Index, in the WIM file, of the first needed entry in the
154 u64 start_table_idx = (start_chunk == 0) ? 0 : start_chunk - 1;
156 /* Number of entries we need to actually read from the chunk
157 * table (excludes the implicit first chunk). */
158 u64 num_needed_chunk_entries = (start_chunk == 0) ?
159 num_needed_chunks - 1 : num_needed_chunks;
161 /* Skip over unneeded chunk table entries. */
162 u64 file_offset_of_needed_chunk_entries = resource_offset +
163 start_table_idx * chunk_entry_size;
164 if (fseeko(fp, file_offset_of_needed_chunk_entries, SEEK_SET) != 0) {
165 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
166 "chunk table of compressed resource",
167 file_offset_of_needed_chunk_entries);
168 return WIMLIB_ERR_READ;
171 /* Number of bytes we need to read from the chunk table. */
172 size_t size = num_needed_chunk_entries * chunk_entry_size;
174 u8 chunk_tab_buf[size];
176 if (fread(chunk_tab_buf, 1, size, fp) != size)
179 /* Now fill in chunk_offsets from the entries we have read in
182 u64 *chunk_tab_p = chunk_offsets;
183 if (start_chunk == 0)
186 if (chunk_entry_size == 4) {
187 u32 *entries = (u32*)chunk_tab_buf;
188 while (num_needed_chunk_entries--)
189 *chunk_tab_p++ = to_le32(*entries++);
191 u64 *entries = (u64*)chunk_tab_buf;
192 while (num_needed_chunk_entries--)
193 *chunk_tab_p++ = to_le64(*entries++);
196 /* Done with the chunk table now. We must now seek to the first chunk
197 * that is needed for the read. */
199 u64 file_offset_of_first_needed_chunk = resource_offset +
200 chunk_table_size + chunk_offsets[0];
201 if (fseeko(fp, file_offset_of_first_needed_chunk, SEEK_SET) != 0) {
202 ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read "
203 "first chunk of compressed resource",
204 file_offset_of_first_needed_chunk);
205 return WIMLIB_ERR_READ;
208 /* Pointer to current position in the output buffer for uncompressed
210 u8 *out_p = (u8*)contents_ret;
212 /* Buffer for compressed data. While most compressed chunks will have a
213 * size much less than WIM_CHUNK_SIZE, WIM_CHUNK_SIZE - 1 is the maximum
214 * size in the worst-case. This assumption is valid only if chunks that
215 * happen to compress to more than the uncompressed size (i.e. a
216 * sequence of random bytes) are always stored uncompressed. But this seems
217 * to be the case in M$'s WIM files, even though it is undocumented. */
218 u8 compressed_buf[WIM_CHUNK_SIZE - 1];
221 /* Decompress all the chunks. */
222 for (u64 i = start_chunk; i <= end_chunk; i++) {
224 DEBUG2("Chunk %"PRIu64" (start %"PRIu64", end %"PRIu64").",
225 i, start_chunk, end_chunk);
227 /* Calculate the sizes of the compressed chunk and of the
228 * uncompressed chunk. */
229 uint compressed_chunk_size, uncompressed_chunk_size;
230 if (i != num_chunks - 1) {
231 /* All the chunks except the last one in the resource
232 * expand to WIM_CHUNK_SIZE uncompressed, and the amount
233 * of compressed data for the chunk is given by the
234 * difference of offsets in the chunk offset table. */
235 compressed_chunk_size = chunk_offsets[i + 1 - start_chunk] -
236 chunk_offsets[i - start_chunk];
237 uncompressed_chunk_size = WIM_CHUNK_SIZE;
239 /* The last compressed chunk consists of the remaining
240 * bytes in the file resource, and the last uncompressed
241 * chunk has size equal to however many bytes are left-
242 * that is, the remainder of the uncompressed size when
243 * divided by WIM_CHUNK_SIZE.
245 * Note that the resource_compressed_size includes the
246 * chunk table, so the size of it must be subtracted. */
247 compressed_chunk_size = resource_compressed_size -
249 chunk_offsets[i - start_chunk];
251 uncompressed_chunk_size = resource_uncompressed_size %
254 /* If the remainder is 0, the last chunk actually
255 * uncompresses to a full WIM_CHUNK_SIZE bytes. */
256 if (uncompressed_chunk_size == 0)
257 uncompressed_chunk_size = WIM_CHUNK_SIZE;
260 DEBUG2("compressed_chunk_size = %u, "
261 "uncompressed_chunk_size = %u",
262 compressed_chunk_size, uncompressed_chunk_size);
265 /* Figure out how much of this chunk we actually need to read */
267 if (i == start_chunk)
268 start_offset = start_chunk_offset;
273 end_offset = end_chunk_offset;
275 end_offset = WIM_CHUNK_SIZE - 1;
277 u64 partial_chunk_size = end_offset + 1 - start_offset;
278 bool is_partial_chunk = (partial_chunk_size !=
279 uncompressed_chunk_size);
281 DEBUG2("start_offset = %u, end_offset = %u", start_offset,
283 DEBUG2("partial_chunk_size = %u", partial_chunk_size);
285 /* This is undocumented, but chunks can be uncompressed. This
286 * appears to always be the case when the compressed chunk size
287 * is equal to the uncompressed chunk size. */
288 if (compressed_chunk_size == uncompressed_chunk_size) {
289 /* Probably an uncompressed chunk */
291 if (start_offset != 0) {
292 if (fseeko(fp, start_offset, SEEK_CUR) != 0) {
293 ERROR_WITH_ERRNO("Uncompressed partial "
294 "chunk fseek() error");
295 return WIMLIB_ERR_READ;
298 if (fread(out_p, 1, partial_chunk_size, fp) !=
302 /* Compressed chunk */
305 /* Read the compressed data into compressed_buf. */
306 if (fread(compressed_buf, 1, compressed_chunk_size,
307 fp) != compressed_chunk_size)
310 /* For partial chunks we must buffer the uncompressed
311 * data because we don't need all of it. */
312 if (is_partial_chunk) {
313 u8 uncompressed_buf[uncompressed_chunk_size];
315 ret = decompress(compressed_buf,
316 compressed_chunk_size,
318 uncompressed_chunk_size);
320 return WIMLIB_ERR_DECOMPRESSION;
321 memcpy(out_p, uncompressed_buf + start_offset,
324 ret = decompress(compressed_buf,
325 compressed_chunk_size,
327 uncompressed_chunk_size);
329 return WIMLIB_ERR_DECOMPRESSION;
333 /* Advance the pointer into the uncompressed output data by the
334 * number of uncompressed bytes that were written. */
335 out_p += partial_chunk_size;
342 ERROR("Unexpected EOF in compressed file resource");
344 ERROR_WITH_ERRNO("Error reading compressed file resource");
345 return WIMLIB_ERR_READ;
349 * Reads uncompressed data from an open file stream.
351 int read_uncompressed_resource(FILE *fp, u64 offset, u64 len,
354 if (fseeko(fp, offset, SEEK_SET) != 0) {
355 ERROR("Failed to seek to byte %"PRIu64" of input file "
356 "to read uncompressed resource (len = %"PRIu64")",
358 return WIMLIB_ERR_READ;
360 if (fread(contents_ret, 1, len, fp) != len) {
362 ERROR("Unexpected EOF in uncompressed file resource");
364 ERROR("Failed to read %"PRIu64" bytes from "
365 "uncompressed resource at offset %"PRIu64,
368 return WIMLIB_ERR_READ;
376 /* Reads the contents of a struct resource_entry, as represented in the on-disk
377 * format, from the memory pointed to by @p, and fills in the fields of @entry.
378 * A pointer to the byte after the memory read at @p is returned. */
379 const u8 *get_resource_entry(const u8 *p, struct resource_entry *entry)
384 p = get_u56(p, &size);
385 p = get_u8(p, &flags);
387 entry->flags = flags;
388 p = get_u64(p, &entry->offset);
389 p = get_u64(p, &entry->original_size);
393 /* Copies the struct resource_entry @entry to the memory pointed to by @p in the
394 * on-disk format. A pointer to the byte after the memory written at @p is
396 u8 *put_resource_entry(u8 *p, const struct resource_entry *entry)
398 p = put_u56(p, entry->size);
399 p = put_u8(p, entry->flags);
400 p = put_u64(p, entry->offset);
401 p = put_u64(p, entry->original_size);
406 * Reads some data from the resource corresponding to a WIM lookup table entry.
408 * @lte: The WIM lookup table entry for the resource.
409 * @buf: Buffer into which to write the data.
410 * @size: Number of bytes to read.
411 * @offset: Offset at which to start reading the resource.
412 * @raw: If %true, compressed data is read literally rather than being
413 * decompressed first.
415 * Returns zero on success, nonzero on failure.
417 int read_wim_resource(const struct lookup_table_entry *lte, u8 buf[],
418 size_t size, u64 offset, bool raw)
420 /* We shouldn't be allowing read over-runs in any part of the library.
423 wimlib_assert(offset + size <= lte->resource_entry.size);
425 wimlib_assert(offset + size <= lte->resource_entry.original_size);
430 switch (lte->resource_location) {
431 case RESOURCE_IN_WIM:
432 /* The resource is in a WIM file, and its WIMStruct is given by
433 * the lte->wim member. The resource may be either compressed
434 * or uncompressed. */
435 wimlib_assert(lte->wim);
436 wimlib_assert(lte->wim->fp);
437 ctype = wim_resource_compression_type(lte);
439 wimlib_assert(ctype != WIM_COMPRESSION_TYPE_NONE ||
440 (lte->resource_entry.original_size ==
441 lte->resource_entry.size));
443 if (raw || ctype == WIM_COMPRESSION_TYPE_NONE)
444 return read_uncompressed_resource(lte->wim->fp,
445 lte->resource_entry.offset + offset,
448 return read_compressed_resource(lte->wim->fp,
449 lte->resource_entry.size,
450 lte->resource_entry.original_size,
451 lte->resource_entry.offset,
452 ctype, size, offset, buf);
454 case RESOURCE_IN_STAGING_FILE:
455 case RESOURCE_IN_FILE_ON_DISK:
456 /* The resource is in some file on the external filesystem and
457 * needs to be read uncompressed */
458 wimlib_assert(lte->file_on_disk);
459 wimlib_assert(<e->file_on_disk == <e->staging_file_name);
460 /* Use existing file pointer if available; otherwise open one
462 if (lte->file_on_disk_fp) {
463 fp = lte->file_on_disk_fp;
465 fp = fopen(lte->file_on_disk, "rb");
467 ERROR_WITH_ERRNO("Failed to open the file "
468 "`%s'", lte->file_on_disk);
471 ret = read_uncompressed_resource(fp, offset, size, buf);
472 if (fp != lte->file_on_disk_fp)
476 case RESOURCE_IN_ATTACHED_BUFFER:
477 /* The resource is directly attached uncompressed in an
478 * in-memory buffer. */
479 wimlib_assert(lte->attached_buffer);
480 memcpy(buf, lte->attached_buffer + offset, size);
484 case RESOURCE_IN_NTFS_VOLUME:
486 if (ntfs_attr_pread(lte->attr, offset, size, buf) == size) {
489 ERROR_WITH_ERRNO("Error reading NTFS attribute "
491 lte->ntfs_loc->path_utf8);
492 return WIMLIB_ERR_NTFS_3G;
505 * Reads all the data from the resource corresponding to a WIM lookup table
508 * @lte: The WIM lookup table entry for the resource.
509 * @buf: Buffer into which to write the data. It must be at least
510 * wim_resource_size(lte) bytes long.
512 * Returns 0 on success; nonzero on failure.
514 int read_full_wim_resource(const struct lookup_table_entry *lte, u8 buf[])
516 return read_wim_resource(lte, buf, wim_resource_size(lte), 0, false);
519 /* Chunk table that's located at the beginning of each compressed resource in
520 * the WIM. (This is not the on-disk format; the on-disk format just has an
521 * array of offsets.) */
525 u64 original_resource_size;
526 u64 bytes_per_chunk_entry;
534 * Allocates and initializes a chunk table, and reserves space for it in the
538 begin_wim_resource_chunk_tab(const struct lookup_table_entry *lte,
541 struct chunk_table **chunk_tab_ret)
543 u64 size = wim_resource_size(lte);
544 u64 num_chunks = (size + WIM_CHUNK_SIZE - 1) / WIM_CHUNK_SIZE;
545 struct chunk_table *chunk_tab = MALLOC(sizeof(struct chunk_table) +
546 num_chunks * sizeof(u64));
549 wimlib_assert(size != 0);
552 ERROR("Failed to allocate chunk table for %"PRIu64" byte "
554 ret = WIMLIB_ERR_NOMEM;
557 chunk_tab->file_offset = file_offset;
558 chunk_tab->num_chunks = num_chunks;
559 chunk_tab->original_resource_size = size;
560 chunk_tab->bytes_per_chunk_entry = (size >= (1ULL << 32)) ? 8 : 4;
561 chunk_tab->table_disk_size = chunk_tab->bytes_per_chunk_entry *
563 chunk_tab->cur_offset = 0;
564 chunk_tab->cur_offset_p = chunk_tab->offsets;
566 if (fwrite(chunk_tab, 1, chunk_tab->table_disk_size, out_fp) !=
567 chunk_tab->table_disk_size) {
568 ERROR_WITH_ERRNO("Failed to write chunk table in compressed "
570 ret = WIMLIB_ERR_WRITE;
574 *chunk_tab_ret = chunk_tab;
580 * Compresses a chunk of a WIM resource.
582 * @chunk: Uncompressed data of the chunk.
583 * @chunk_size: Size of the uncompressed chunk in bytes.
584 * @compressed_chunk: Pointer to output buffer of size at least
585 * (@chunk_size - 1) bytes.
586 * @compressed_chunk_len_ret: Pointer to an unsigned int into which the size
587 * of the compressed chunk will be
589 * @ctype: Type of compression to use. Must be WIM_COMPRESSION_TYPE_LZX
590 * or WIM_COMPRESSION_TYPE_XPRESS.
592 * Returns zero if compressed succeeded, and nonzero if the chunk could not be
593 * compressed to any smaller than @chunk_size. This function cannot fail for
596 static int compress_chunk(const u8 chunk[], unsigned chunk_size,
597 u8 compressed_chunk[],
598 unsigned *compressed_chunk_len_ret,
601 unsigned compressed_chunk_sz;
602 int (*compress)(const void *, unsigned, void *, unsigned *);
604 case WIM_COMPRESSION_TYPE_LZX:
605 compress = lzx_compress;
607 case WIM_COMPRESSION_TYPE_XPRESS:
608 compress = xpress_compress;
614 return (*compress)(chunk, chunk_size, compressed_chunk,
615 compressed_chunk_len_ret);
619 * Writes a chunk of a WIM resource to an output file.
621 * @chunk: Uncompressed data of the chunk.
622 * @chunk_size: Size of the chunk (<= WIM_CHUNK_SIZE)
623 * @out_fp: FILE * to write tho chunk to.
624 * @out_ctype: Compression type to use when writing the chunk (ignored if no
625 * chunk table provided)
626 * @chunk_tab: Pointer to chunk table being created. It is updated with the
627 * offset of the chunk we write.
629 * Returns 0 on success; nonzero on failure.
631 static int write_wim_resource_chunk(const u8 chunk[], unsigned chunk_size,
632 FILE *out_fp, int out_ctype,
633 struct chunk_table *chunk_tab)
636 unsigned out_chunk_size;
638 wimlib_assert(chunk_size <= WIM_CHUNK_SIZE);
642 out_chunk_size = chunk_size;
644 u8 *compressed_chunk = alloca(chunk_size);
646 unsigned compressed_chunk_len;
648 ret = compress_chunk(chunk, chunk_size, compressed_chunk,
649 &out_chunk_size, out_ctype);
651 out_chunk = compressed_chunk;
654 out_chunk_size = chunk_size;
656 *chunk_tab->cur_offset_p++ = chunk_tab->cur_offset;
657 chunk_tab->cur_offset += out_chunk_size;
660 if (fwrite(out_chunk, 1, out_chunk_size, out_fp) != out_chunk_size) {
661 ERROR_WITH_ERRNO("Failed to write WIM resource chunk");
662 return WIMLIB_ERR_WRITE;
668 * Finishes a WIM chunk tale and writes it to the output file at the correct
671 * The final size of the full compressed resource is returned in the
672 * @compressed_size_p.
675 finish_wim_resource_chunk_tab(struct chunk_table *chunk_tab,
676 FILE *out_fp, u64 *compressed_size_p)
678 size_t bytes_written;
679 if (fseeko(out_fp, chunk_tab->file_offset, SEEK_SET) != 0) {
680 ERROR_WITH_ERRNO("Failed to seek to byte "PRIu64" of output "
681 "WIM file", chunk_tab->file_offset);
682 return WIMLIB_ERR_WRITE;
685 if (chunk_tab->bytes_per_chunk_entry == 8) {
686 array_to_le64(chunk_tab->offsets, chunk_tab->num_chunks);
688 for (u64 i = 0; i < chunk_tab->num_chunks; i++)
689 ((u32*)chunk_tab->offsets)[i] =
690 to_le32(chunk_tab->offsets[i]);
692 bytes_written = fwrite((u8*)chunk_tab->offsets +
693 chunk_tab->bytes_per_chunk_entry,
694 1, chunk_tab->table_disk_size, out_fp);
695 if (bytes_written != chunk_tab->table_disk_size) {
696 ERROR_WITH_ERRNO("Failed to write chunk table in compressed "
698 return WIMLIB_ERR_WRITE;
700 if (fseeko(out_fp, 0, SEEK_END) != 0) {
701 ERROR_WITH_ERRNO("Failed to seek to end of output WIM file");
702 return WIMLIB_ERR_WRITE;
704 *compressed_size_p = chunk_tab->cur_offset + chunk_tab->table_disk_size;
709 * Writes a WIM resource to a FILE * opened for writing. The resource may be
710 * written uncompressed or compressed depending on the @out_ctype parameter.
712 * If by chance the resource compresses to more than the original size (this may
713 * happen with random data or files than are pre-compressed), the resource is
714 * instead written uncompressed (and this is reflected in the @out_res_entry by
715 * removing the WIM_RESHDR_FLAG_COMPRESSED flag).
717 * @lte: The lookup table entry for the WIM resource.
718 * @out_fp: The FILE * to write the resource to.
719 * @out_ctype: The compression type of the resource to write. Note: if this is
720 * the same as the compression type of the WIM resource we
721 * need to read, we simply copy the data (i.e. we do not
722 * uncompress it, then compress it again).
723 * @out_res_entry: If non-NULL, a resource entry that is filled in with the
724 * offset, original size, compressed size, and compression flag
725 * of the output resource.
727 * Returns 0 on success; nonzero on failure.
729 static int write_wim_resource(struct lookup_table_entry *lte,
730 FILE *out_fp, int out_ctype,
731 struct resource_entry *out_res_entry)
735 u64 old_compressed_size;
736 u64 new_compressed_size;
739 struct chunk_table *chunk_tab = NULL;
746 /* Original size of the resource */
747 original_size = wim_resource_size(lte);
749 /* Compressed size of the resource (as it exists now) */
750 old_compressed_size = wim_resource_compressed_size(lte);
752 /* Current offset in output file */
753 file_offset = ftello(out_fp);
754 if (file_offset == -1) {
755 ERROR_WITH_ERRNO("Failed to get offset in output "
757 return WIMLIB_ERR_WRITE;
760 /* Are the compression types the same? If so, do a raw copy (copy
761 * without decompressing and recompressing the data). */
762 raw = (wim_resource_compression_type(lte) == out_ctype
763 && out_ctype != WIM_COMPRESSION_TYPE_NONE);
765 bytes_remaining = old_compressed_size;
767 bytes_remaining = original_size;
769 /* Empty resource; nothing needs to be done, so just return success. */
770 if (bytes_remaining == 0)
773 /* Buffer for reading chunks for the resource */
774 char buf[min(WIM_CHUNK_SIZE, bytes_remaining)];
776 /* If we are writing a compressed resource and not doing a raw copy, we
777 * need to initialize the chunk table */
778 if (out_ctype != WIM_COMPRESSION_TYPE_NONE && !raw) {
779 ret = begin_wim_resource_chunk_tab(lte, out_fp, file_offset,
785 /* If the WIM resource is in an external file, open a FILE * to it so we
786 * don't have to open a temporary one in read_wim_resource() for each
788 if (lte->resource_location == RESOURCE_IN_FILE_ON_DISK
789 && !lte->file_on_disk_fp)
791 wimlib_assert(lte->file_on_disk);
792 lte->file_on_disk_fp = fopen(lte->file_on_disk, "rb");
793 if (!lte->file_on_disk_fp) {
794 ERROR_WITH_ERRNO("Failed to open the file `%s' for "
795 "reading", lte->file_on_disk);
796 ret = WIMLIB_ERR_OPEN;
801 else if (lte->resource_location == RESOURCE_IN_NTFS_VOLUME
804 struct ntfs_location *loc = lte->ntfs_loc;
806 ni = ntfs_pathname_to_inode(*loc->ntfs_vol_p, NULL, loc->path_utf8);
808 ERROR_WITH_ERRNO("Failed to open inode `%s' in NTFS "
809 "volume", loc->path_utf8);
811 lte->attr = ntfs_attr_open(ni,
812 loc->is_reparse_point ? AT_REPARSE_POINT : AT_DATA,
813 (ntfschar*)loc->stream_name_utf16,
814 loc->stream_name_utf16_num_chars);
816 ntfs_inode_close(ni);
817 ERROR_WITH_ERRNO("Failed to open attribute of `%s' in "
818 "NTFS volume", loc->path_utf8);
823 /* If we aren't doing a raw copy, we will compute the SHA1 message
824 * digest of the resource as we read it, and verify it's the same as the
825 * hash given in the lookup table entry once we've finished reading the
831 /* While there are still bytes remaining in the WIM resource, read a
832 * chunk of the resource, update SHA1, then write that chunk using the
833 * desired compression type. */
835 u64 to_read = min(bytes_remaining, WIM_CHUNK_SIZE);
836 ret = read_wim_resource(lte, buf, to_read, offset, raw);
840 sha1_update(&ctx, buf, to_read);
841 ret = write_wim_resource_chunk(buf, to_read, out_fp,
842 out_ctype, chunk_tab);
845 bytes_remaining -= to_read;
847 } while (bytes_remaining);
849 /* If writing a compressed resource and not doing a raw copy, write the
850 * chunk table, and finish_wim_resource_chunk_tab() will provide the
851 * compressed size of the resource we wrote. Otherwise, the compressed
852 * size of the written resource is the same as the compressed size of
853 * the existing resource. */
854 if (out_ctype != WIM_COMPRESSION_TYPE_NONE && !raw) {
855 ret = finish_wim_resource_chunk_tab(chunk_tab, out_fp,
856 &new_compressed_size);
860 new_compressed_size = old_compressed_size;
863 /* Verify SHA1 message digest of the resource, unless we are doing a raw
864 * write (in which case we never even saw the uncompressed data). Or,
865 * if the hash we had before is all 0's, just re-set it to be the new
868 u8 md[SHA1_HASH_SIZE];
869 sha1_final(md, &ctx);
870 if (is_zero_hash(lte->hash)) {
871 copy_hash(lte->hash, md);
872 } else if (!hashes_equal(md, lte->hash)) {
873 ERROR("WIM resource has incorrect hash!");
874 if (lte->resource_location == RESOURCE_IN_FILE_ON_DISK) {
875 ERROR("We were reading it from `%s'; maybe it changed "
876 "while we were reading it.",
879 ret = WIMLIB_ERR_INVALID_RESOURCE_HASH;
884 if (new_compressed_size > original_size) {
885 /* Oops! We compressed the resource to larger than the original
886 * size. Write the resource uncompressed instead. */
887 if (fseeko(out_fp, file_offset, SEEK_SET) != 0) {
888 ERROR_WITH_ERRNO("Failed to seek to byte "PRIu64" "
889 "of output WIM file", file_offset);
890 ret = WIMLIB_ERR_WRITE;
893 ret = write_wim_resource(lte, out_fp, WIM_COMPRESSION_TYPE_NONE,
897 if (fflush(out_fp) != 0) {
898 ERROR_WITH_ERRNO("Failed to flush output WIM file");
899 ret = WIMLIB_ERR_WRITE;
902 if (ftruncate(fileno(out_fp), file_offset + out_res_entry->size) != 0) {
903 ERROR_WITH_ERRNO("Failed to truncate output WIM file");
904 ret = WIMLIB_ERR_WRITE;
908 wimlib_assert(new_compressed_size <= original_size);
910 out_res_entry->size = new_compressed_size;
911 out_res_entry->original_size = original_size;
912 out_res_entry->offset = file_offset;
913 out_res_entry->flags = lte->resource_entry.flags
914 & ~WIM_RESHDR_FLAG_COMPRESSED;
915 if (out_ctype != WIM_COMPRESSION_TYPE_NONE)
916 out_res_entry->flags |= WIM_RESHDR_FLAG_COMPRESSED;
919 if (lte->resource_location == RESOURCE_IN_FILE_ON_DISK
920 && lte->file_on_disk_fp) {
921 fclose(lte->file_on_disk_fp);
922 lte->file_on_disk_fp = NULL;
925 else if (lte->resource_location == RESOURCE_IN_NTFS_VOLUME
927 ntfs_attr_close(lte->attr);
928 ntfs_inode_close(ni);
936 /* Like write_wim_resource(), but the resource is specified by a buffer of
937 * uncompressed data rather a lookup table entry; also writes the SHA1 hash of
938 * the buffer to @hash. */
939 static int write_wim_resource_from_buffer(const u8 *buf, u64 buf_size,
940 FILE *out_fp, int out_ctype,
941 struct resource_entry *out_res_entry,
942 u8 hash[SHA1_HASH_SIZE])
944 /* Set up a temporary lookup table entry that we provide to
945 * write_wim_resource(). */
946 struct lookup_table_entry lte;
948 lte.resource_entry.flags = 0;
949 lte.resource_entry.original_size = buf_size;
950 lte.resource_entry.size = buf_size;
951 lte.resource_entry.offset = 0;
952 lte.resource_location = RESOURCE_IN_ATTACHED_BUFFER;
953 lte.attached_buffer = (u8*)buf;
956 ret = write_wim_resource(<e, out_fp, out_ctype, out_res_entry);
959 copy_hash(hash, lte.hash);
964 * Extracts the first @size bytes of the WIM resource specified by @lte to the
965 * open file descriptor @fd.
967 * Returns 0 on success; nonzero on failure.
969 int extract_wim_resource_to_fd(const struct lookup_table_entry *lte, int fd,
972 u64 bytes_remaining = size;
973 char buf[min(WIM_CHUNK_SIZE, bytes_remaining)];
976 u8 hash[SHA1_HASH_SIZE];
981 while (bytes_remaining) {
982 u64 to_read = min(bytes_remaining, WIM_CHUNK_SIZE);
983 ret = read_wim_resource(lte, buf, to_read, offset, false);
986 sha1_update(&ctx, buf, to_read);
987 if (full_write(fd, buf, to_read) < 0) {
988 ERROR_WITH_ERRNO("Error extracting WIM resource");
989 return WIMLIB_ERR_WRITE;
991 bytes_remaining -= to_read;
994 sha1_final(hash, &ctx);
995 if (!hashes_equal(hash, lte->hash)) {
996 ERROR("Invalid checksum on a WIM resource "
997 "(detected when extracting to external file)");
998 ERROR("The following WIM resource is invalid:");
999 print_lookup_table_entry(lte);
1000 return WIMLIB_ERR_INVALID_RESOURCE_HASH;
1006 * Extracts the WIM resource specified by @lte to the open file descriptor @fd.
1008 * Returns 0 on success; nonzero on failure.
1010 int extract_full_wim_resource_to_fd(const struct lookup_table_entry *lte, int fd)
1012 return extract_wim_resource_to_fd(lte, fd, wim_resource_size(lte));
1016 * Copies the file resource specified by the lookup table entry @lte from the
1017 * input WIM to the output WIM that has its FILE * given by
1018 * ((WIMStruct*)wim)->out_fp.
1020 * The output_resource_entry, out_refcnt, and part_number fields of @lte are
1023 * Metadata resources are not copied (they are handled elsewhere for joining and
1026 int copy_resource(struct lookup_table_entry *lte, void *wim)
1031 if ((lte->resource_entry.flags & WIM_RESHDR_FLAG_METADATA) &&
1035 ret = write_wim_resource(lte, w->out_fp,
1036 wim_resource_compression_type(lte),
1037 <e->output_resource_entry);
1040 lte->out_refcnt = lte->refcnt;
1041 lte->part_number = w->hdr.part_number;
1046 * Writes a dentry's resources, including the main file resource as well as all
1047 * alternate data streams, to the output file.
1049 * @dentry: The dentry for the file.
1050 * @wim_p: A pointer to the WIMStruct containing @dentry.
1052 * @return zero on success, nonzero on failure.
1054 int write_dentry_resources(struct dentry *dentry, void *wim_p)
1056 WIMStruct *w = wim_p;
1058 struct lookup_table_entry *lte;
1059 int ctype = wimlib_get_compression_type(w);
1061 if (w->write_flags & WIMLIB_WRITE_FLAG_VERBOSE) {
1062 wimlib_assert(dentry->full_path_utf8);
1063 printf("Writing streams for `%s'\n", dentry->full_path_utf8);
1066 for (unsigned i = 0; i <= dentry->num_ads; i++) {
1067 lte = dentry_stream_lte(dentry, i, w->lookup_table);
1068 if (lte && ++lte->out_refcnt == 1) {
1069 ret = write_wim_resource(lte, w->out_fp, ctype,
1070 <e->output_resource_entry);
1079 * Reads the metadata metadata resource from the WIM file. The metadata
1080 * resource consists of the security data, followed by the directory entry for
1081 * the root directory, followed by all the other directory entries in the
1082 * filesystem. The subdir_offset field of each directory entry gives the start
1083 * of its child entries from the beginning of the metadata resource. An
1084 * end-of-directory is signaled by a directory entry of length '0', really of
1085 * length 8, because that's how long the 'length' field is.
1087 * @fp: The FILE* for the input WIM file.
1088 * @wim_ctype: The compression type of the WIM file.
1089 * @imd: Pointer to the image metadata structure. Its `metadata_lte'
1090 * member specifies the lookup table entry for the metadata
1091 * resource. The rest of the image metadata entry will be filled
1092 * in by this function.
1094 * @return: Zero on success, nonzero on failure.
1096 int read_metadata_resource(FILE *fp, int wim_ctype, struct image_metadata *imd)
1102 struct dentry *dentry;
1103 struct wim_security_data *sd;
1104 struct link_group_table *lgt;
1105 const struct lookup_table_entry *metadata_lte;
1107 u64 metadata_offset;
1109 metadata_lte = imd->metadata_lte;
1110 metadata_len = wim_resource_size(metadata_lte);
1111 metadata_offset = metadata_lte->resource_entry.offset;
1113 DEBUG("Reading metadata resource: length = %"PRIu64", "
1114 "offset = %"PRIu64"", metadata_len, metadata_offset);
1116 /* There is no way the metadata resource could possibly be less than (8
1117 * + WIM_DENTRY_DISK_SIZE) bytes, where the 8 is for security data (with
1118 * no security descriptors) and WIM_DENTRY_DISK_SIZE is for the root
1120 if (metadata_len < 8 + WIM_DENTRY_DISK_SIZE) {
1121 ERROR("Expected at least %zu bytes for the metadata resource",
1122 8 + WIM_DENTRY_DISK_SIZE);
1123 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
1126 /* Allocate memory for the uncompressed metadata resource. */
1127 buf = MALLOC(metadata_len);
1130 ERROR("Failed to allocate %"PRIu64" bytes for uncompressed "
1131 "metadata resource", metadata_len);
1132 return WIMLIB_ERR_NOMEM;
1135 /* Read the metadata resource into memory. (It may be compressed.) */
1136 ret = read_full_wim_resource(metadata_lte, buf);
1140 DEBUG("Finished reading metadata resource into memory.");
1142 /* The root directory entry starts after security data, aligned on an
1143 * 8-byte boundary within the metadata resource.
1145 * The security data starts with a 4-byte integer giving its total
1146 * length, so if we round that up to an 8-byte boundary that gives us
1147 * the offset of the root dentry.
1149 * Here we read the security data into a wim_security_data structure,
1150 * and if successful, go ahead and calculate the offset in the metadata
1151 * resource of the root dentry. */
1153 ret = read_security_data(buf, metadata_len, &sd);
1157 get_u32(buf, &dentry_offset);
1158 if (dentry_offset == 0)
1160 dentry_offset = (dentry_offset + 7) & ~7;
1162 /* Allocate memory for the root dentry and read it into memory */
1163 dentry = MALLOC(sizeof(struct dentry));
1165 ERROR("Failed to allocate %zu bytes for root dentry",
1166 sizeof(struct dentry));
1167 ret = WIMLIB_ERR_NOMEM;
1168 goto out_free_security_data;
1171 ret = read_dentry(buf, metadata_len, dentry_offset, dentry);
1173 /* This is the root dentry, so set its pointers correctly. */
1174 dentry->parent = dentry;
1175 dentry->next = dentry;
1176 dentry->prev = dentry;
1178 goto out_free_dentry_tree;
1180 /* Now read the entire directory entry tree into memory. */
1181 DEBUG("Reading dentry tree");
1182 ret = read_dentry_tree(buf, metadata_len, dentry);
1184 goto out_free_dentry_tree;
1186 /* Calculate the full paths in the dentry tree. */
1187 DEBUG("Calculating dentry full paths");
1188 ret = for_dentry_in_tree(dentry, calculate_dentry_full_path, NULL);
1190 goto out_free_dentry_tree;
1192 /* Build hash table that maps hard link group IDs to dentry sets */
1193 DEBUG("Building link group table");
1194 lgt = new_link_group_table(9001);
1196 goto out_free_dentry_tree;
1197 ret = for_dentry_in_tree(dentry, link_group_table_insert, lgt);
1201 DEBUG("Freeing duplicate ADS entries in link group table");
1202 ret = link_groups_free_duplicate_data(lgt);
1205 DEBUG("Done reading image metadata");
1208 imd->security_data = sd;
1209 imd->root_dentry = dentry;
1212 free_link_group_table(lgt);
1213 out_free_dentry_tree:
1214 free_dentry_tree(dentry, NULL);
1215 out_free_security_data:
1216 free_security_data(sd);
1222 /* Write the metadata resource for the current WIM image. */
1223 int write_metadata_resource(WIMStruct *w)
1229 struct dentry *root;
1230 struct lookup_table_entry *lte, *duplicate_lte;
1231 u64 metadata_original_size;
1232 const struct wim_security_data *sd;
1233 const unsigned random_tail_len = 20;
1235 DEBUG("Writing metadata resource for image %d", w->current_image);
1237 root = wim_root_dentry(w);
1238 sd = wim_security_data(w);
1240 /* We do not allow the security data pointer to be NULL, although it may
1241 * point to an empty security data with no entries. */
1244 /* Offset of first child of the root dentry. It's equal to:
1245 * - The total length of the security data, rounded to the next 8-byte
1247 * - plus the total length of the root dentry,
1248 * - plus 8 bytes for an end-of-directory entry following the root
1249 * dentry (shouldn't really be needed, but just in case...)
1251 subdir_offset = ((sd->total_length + 7) & ~7) + dentry_total_length(root) + 8;
1253 /* Calculate the subdirectory offsets for the entire dentry tree. */
1254 calculate_subdir_offsets(root, &subdir_offset);
1256 /* Total length of the metadata resource (uncompressed) */
1257 metadata_original_size = subdir_offset + random_tail_len;
1259 /* Allocate a buffer to contain the uncompressed metadata resource */
1260 buf = MALLOC(metadata_original_size);
1262 ERROR("Failed to allocate %"PRIu64" bytes for "
1263 "metadata resource", metadata_original_size);
1264 return WIMLIB_ERR_NOMEM;
1267 /* Write the security data into the resource buffer */
1268 p = write_security_data(sd, buf);
1270 /* Write the dentry tree into the resource buffer */
1271 DEBUG("Writing dentry tree.");
1272 p = write_dentry_tree(root, p);
1275 * Append 20 random bytes to the metadata resource so that we don't have
1276 * identical metadata resources if we happen to append exactly the same
1277 * image twice without any changes in timestamps. If this were to
1278 * happen, it would cause confusion about the number and order of images
1281 randomize_byte_array(p, random_tail_len);
1283 /* We MUST have exactly filled the buffer; otherwise we calculated its
1284 * size incorrectly or wrote the data incorrectly. */
1285 wimlib_assert(p - buf + random_tail_len == metadata_original_size);
1287 /* Get the lookup table entry for the metadata resource so we can update
1289 lte = wim_metadata_lookup_table_entry(w);
1291 /* Write the metadata resource to the output WIM using the proper
1292 * compression type. The lookup table entry for the metadata resource
1294 ret = write_wim_resource_from_buffer(buf, metadata_original_size,
1296 wimlib_get_compression_type(w),
1297 <e->output_resource_entry,
1302 /* It's very likely the SHA1 message digest of the metadata resource, so
1303 * re-insert the lookup table entry into the lookup table. */
1304 lookup_table_unlink(w->lookup_table, lte);
1305 lookup_table_insert(w->lookup_table, lte);
1307 /* We do not allow a metadata resource to be referenced multiple times,
1308 * and the 20 random bytes appended to it should make it extremely
1309 * likely for each metadata resource to be unique, even if the exact
1310 * same image is captured. */
1311 wimlib_assert(lte->out_refcnt == 0);
1312 lte->out_refcnt = 1;
1314 /* Make sure that the resource entry is written marked with the metadata
1316 lte->output_resource_entry.flags |= WIM_RESHDR_FLAG_METADATA;
1318 /* All the data has been written to the new WIM; no need for the buffer