/* * resource.c * * Read uncompressed and compressed metadata and file resources. */ /* * Copyright (C) 2012 Eric Biggers * * This file is part of wimlib, a library for working with WIM files. * * wimlib is free software; you can redistribute it and/or modify it under the * terms of the GNU General Public License as published by the Free Software * Foundation; either version 3 of the License, or (at your option) any later * version. * * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR * A PARTICULAR PURPOSE. See the GNU General Public License for more details. * * You should have received a copy of the GNU General Public License along with * wimlib; if not, see http://www.gnu.org/licenses/. */ #include "config.h" #include #include #include "dentry.h" #include "wimlib_internal.h" #include "lookup_table.h" #include "io.h" #include "lzx.h" #include "xpress.h" #include "sha1.h" #include #include #ifdef WITH_NTFS_3G #include #include #include #include #endif /* * Reads all or part of a compressed resource into an in-memory buffer. * * @fp: The FILE* for the WIM file. * @resource_compressed_size: The compressed size of the resource. * @resource_uncompressed_size: The uncompressed size of the resource. * @resource_offset: The offset of the start of the resource from * the start of the stream @fp. * @resource_ctype: The compression type of the resource. * @len: The number of bytes of uncompressed data to read from * the resource. * @offset: The offset of the bytes to read within the uncompressed * resource. * @contents_len: An array into which the uncompressed data is written. * It must be at least @len bytes long. * * Returns zero on success, nonzero on failure. */ static int read_compressed_resource(FILE *fp, u64 resource_compressed_size, u64 resource_uncompressed_size, u64 resource_offset, int resource_ctype, u64 len, u64 offset, u8 contents_ret[]) { DEBUG2("comp size = %"PRIu64", uncomp size = %"PRIu64", " "res offset = %"PRIu64"", resource_compressed_size, resource_uncompressed_size, resource_offset); DEBUG2("resource_ctype = %s, len = %"PRIu64", offset = %"PRIu64"", wimlib_get_compression_type_string(resource_ctype), len, offset); /* Trivial case */ if (len == 0) return 0; int (*decompress)(const void *, uint, void *, uint); /* Set the appropriate decompress function. */ if (resource_ctype == WIM_COMPRESSION_TYPE_LZX) decompress = lzx_decompress; else decompress = xpress_decompress; /* The structure of a compressed resource consists of a table of chunk * offsets followed by the chunks themselves. Each chunk consists of * compressed data, and there is one chunk for each WIM_CHUNK_SIZE = * 32768 bytes of the uncompressed file, with the last chunk having any * remaining bytes. * * The chunk offsets are measured relative to the end of the chunk * table. The first chunk is omitted from the table in the WIM file * because its offset is implicitly given by the fact that it directly * follows the chunk table and therefore must have an offset of 0. */ /* Calculate how many chunks the resource conists of in its entirety. */ u64 num_chunks = (resource_uncompressed_size + WIM_CHUNK_SIZE - 1) / WIM_CHUNK_SIZE; /* As mentioned, the first chunk has no entry in the chunk table. */ u64 num_chunk_entries = num_chunks - 1; /* The index of the chunk that the read starts at. */ u64 start_chunk = offset / WIM_CHUNK_SIZE; /* The byte offset at which the read starts, within the start chunk. */ u64 start_chunk_offset = offset % WIM_CHUNK_SIZE; /* The index of the chunk that contains the last byte of the read. */ u64 end_chunk = (offset + len - 1) / WIM_CHUNK_SIZE; /* The byte offset of the last byte of the read, within the end chunk */ u64 end_chunk_offset = (offset + len - 1) % WIM_CHUNK_SIZE; /* Number of chunks that are actually needed to read the requested part * of the file. */ u64 num_needed_chunks = end_chunk - start_chunk + 1; /* If the end chunk is not the last chunk, an extra chunk entry is * needed because we need to know the offset of the chunk after the last * chunk read to figure out the size of the last read chunk. */ if (end_chunk != num_chunks - 1) num_needed_chunks++; /* Declare the chunk table. It will only contain offsets for the chunks * that are actually needed for this read. */ u64 chunk_offsets[num_needed_chunks]; /* Set the implicit offset of the first chunk if it is included in the * needed chunks. * * Note: M$'s documentation includes a picture that shows the first * chunk starting right after the chunk entry table, labeled as offset * 0x10. However, in the actual file format, the offset is measured * from the end of the chunk entry table, so the first chunk has an * offset of 0. */ if (start_chunk == 0) chunk_offsets[0] = 0; /* According to M$'s documentation, if the uncompressed size of * the file is greater than 4 GB, the chunk entries are 8-byte * integers. Otherwise, they are 4-byte integers. */ u64 chunk_entry_size = (resource_uncompressed_size >= (u64)1 << 32) ? 8 : 4; /* Size of the full chunk table in the WIM file. */ u64 chunk_table_size = chunk_entry_size * num_chunk_entries; /* Read the needed chunk offsets from the table in the WIM file. */ /* Index, in the WIM file, of the first needed entry in the * chunk table. */ u64 start_table_idx = (start_chunk == 0) ? 0 : start_chunk - 1; /* Number of entries we need to actually read from the chunk * table (excludes the implicit first chunk). */ u64 num_needed_chunk_entries = (start_chunk == 0) ? num_needed_chunks - 1 : num_needed_chunks; /* Skip over unneeded chunk table entries. */ u64 file_offset_of_needed_chunk_entries = resource_offset + start_table_idx * chunk_entry_size; if (fseeko(fp, file_offset_of_needed_chunk_entries, SEEK_SET) != 0) { ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read " "chunk table of compressed resource", file_offset_of_needed_chunk_entries); return WIMLIB_ERR_READ; } /* Number of bytes we need to read from the chunk table. */ size_t size = num_needed_chunk_entries * chunk_entry_size; u8 chunk_tab_buf[size]; if (fread(chunk_tab_buf, 1, size, fp) != size) goto err; /* Now fill in chunk_offsets from the entries we have read in * chunk_tab_buf. */ u64 *chunk_tab_p = chunk_offsets; if (start_chunk == 0) chunk_tab_p++; if (chunk_entry_size == 4) { u32 *entries = (u32*)chunk_tab_buf; while (num_needed_chunk_entries--) *chunk_tab_p++ = le32_to_cpu(*entries++); } else { u64 *entries = (u64*)chunk_tab_buf; while (num_needed_chunk_entries--) *chunk_tab_p++ = le64_to_cpu(*entries++); } /* Done with the chunk table now. We must now seek to the first chunk * that is needed for the read. */ u64 file_offset_of_first_needed_chunk = resource_offset + chunk_table_size + chunk_offsets[0]; if (fseeko(fp, file_offset_of_first_needed_chunk, SEEK_SET) != 0) { ERROR_WITH_ERRNO("Failed to seek to byte %"PRIu64" to read " "first chunk of compressed resource", file_offset_of_first_needed_chunk); return WIMLIB_ERR_READ; } /* Pointer to current position in the output buffer for uncompressed * data. */ u8 *out_p = (u8*)contents_ret; /* Buffer for compressed data. While most compressed chunks will have a * size much less than WIM_CHUNK_SIZE, WIM_CHUNK_SIZE - 1 is the maximum * size in the worst-case. This assumption is valid only if chunks that * happen to compress to more than the uncompressed size (i.e. a * sequence of random bytes) are always stored uncompressed. But this seems * to be the case in M$'s WIM files, even though it is undocumented. */ u8 compressed_buf[WIM_CHUNK_SIZE - 1]; /* Decompress all the chunks. */ for (u64 i = start_chunk; i <= end_chunk; i++) { DEBUG2("Chunk %"PRIu64" (start %"PRIu64", end %"PRIu64").", i, start_chunk, end_chunk); /* Calculate the sizes of the compressed chunk and of the * uncompressed chunk. */ uint compressed_chunk_size, uncompressed_chunk_size; if (i != num_chunks - 1) { /* All the chunks except the last one in the resource * expand to WIM_CHUNK_SIZE uncompressed, and the amount * of compressed data for the chunk is given by the * difference of offsets in the chunk offset table. */ compressed_chunk_size = chunk_offsets[i + 1 - start_chunk] - chunk_offsets[i - start_chunk]; uncompressed_chunk_size = WIM_CHUNK_SIZE; } else { /* The last compressed chunk consists of the remaining * bytes in the file resource, and the last uncompressed * chunk has size equal to however many bytes are left- * that is, the remainder of the uncompressed size when * divided by WIM_CHUNK_SIZE. * * Note that the resource_compressed_size includes the * chunk table, so the size of it must be subtracted. */ compressed_chunk_size = resource_compressed_size - chunk_table_size - chunk_offsets[i - start_chunk]; uncompressed_chunk_size = resource_uncompressed_size % WIM_CHUNK_SIZE; /* If the remainder is 0, the last chunk actually * uncompresses to a full WIM_CHUNK_SIZE bytes. */ if (uncompressed_chunk_size == 0) uncompressed_chunk_size = WIM_CHUNK_SIZE; } DEBUG2("compressed_chunk_size = %u, " "uncompressed_chunk_size = %u", compressed_chunk_size, uncompressed_chunk_size); /* Figure out how much of this chunk we actually need to read */ u64 start_offset; if (i == start_chunk) start_offset = start_chunk_offset; else start_offset = 0; u64 end_offset; if (i == end_chunk) end_offset = end_chunk_offset; else end_offset = WIM_CHUNK_SIZE - 1; u64 partial_chunk_size = end_offset + 1 - start_offset; bool is_partial_chunk = (partial_chunk_size != uncompressed_chunk_size); DEBUG2("start_offset = %u, end_offset = %u", start_offset, end_offset); DEBUG2("partial_chunk_size = %u", partial_chunk_size); /* This is undocumented, but chunks can be uncompressed. This * appears to always be the case when the compressed chunk size * is equal to the uncompressed chunk size. */ if (compressed_chunk_size == uncompressed_chunk_size) { /* Probably an uncompressed chunk */ if (start_offset != 0) { if (fseeko(fp, start_offset, SEEK_CUR) != 0) { ERROR_WITH_ERRNO("Uncompressed partial " "chunk fseek() error"); return WIMLIB_ERR_READ; } } if (fread(out_p, 1, partial_chunk_size, fp) != partial_chunk_size) goto err; } else { /* Compressed chunk */ int ret; /* Read the compressed data into compressed_buf. */ if (fread(compressed_buf, 1, compressed_chunk_size, fp) != compressed_chunk_size) goto err; /* For partial chunks we must buffer the uncompressed * data because we don't need all of it. */ if (is_partial_chunk) { u8 uncompressed_buf[uncompressed_chunk_size]; ret = decompress(compressed_buf, compressed_chunk_size, uncompressed_buf, uncompressed_chunk_size); if (ret != 0) return WIMLIB_ERR_DECOMPRESSION; memcpy(out_p, uncompressed_buf + start_offset, partial_chunk_size); } else { ret = decompress(compressed_buf, compressed_chunk_size, out_p, uncompressed_chunk_size); if (ret != 0) return WIMLIB_ERR_DECOMPRESSION; } } /* Advance the pointer into the uncompressed output data by the * number of uncompressed bytes that were written. */ out_p += partial_chunk_size; } return 0; err: if (feof(fp)) ERROR("Unexpected EOF in compressed file resource"); else ERROR_WITH_ERRNO("Error reading compressed file resource"); return WIMLIB_ERR_READ; } /* * Reads uncompressed data from an open file stream. */ int read_uncompressed_resource(FILE *fp, u64 offset, u64 len, u8 contents_ret[]) { if (fseeko(fp, offset, SEEK_SET) != 0) { ERROR("Failed to seek to byte %"PRIu64" of input file " "to read uncompressed resource (len = %"PRIu64")", offset, len); return WIMLIB_ERR_READ; } if (fread(contents_ret, 1, len, fp) != len) { if (feof(fp)) { ERROR("Unexpected EOF in uncompressed file resource"); } else { ERROR("Failed to read %"PRIu64" bytes from " "uncompressed resource at offset %"PRIu64, len, offset); } return WIMLIB_ERR_READ; } return 0; } /* Reads the contents of a struct resource_entry, as represented in the on-disk * format, from the memory pointed to by @p, and fills in the fields of @entry. * A pointer to the byte after the memory read at @p is returned. */ const u8 *get_resource_entry(const u8 *p, struct resource_entry *entry) { u64 size; u8 flags; p = get_u56(p, &size); p = get_u8(p, &flags); entry->size = size; entry->flags = flags; /* offset and original_size are truncated to 62 bits to avoid possible * overflows, when converting to a signed 64-bit integer (off_t) or when * adding size or original_size. This is okay since no one would ever * actually have a WIM bigger than 4611686018427387903 bytes... */ p = get_u64(p, &entry->offset); if (entry->offset & 0xc000000000000000ULL) { WARNING("Truncating offset in resource entry"); entry->offset &= 0x3fffffffffffffffULL; } p = get_u64(p, &entry->original_size); if (entry->original_size & 0xc000000000000000ULL) { WARNING("Truncating original_size in resource entry"); entry->original_size &= 0x3fffffffffffffffULL; } return p; } /* Copies the struct resource_entry @entry to the memory pointed to by @p in the * on-disk format. A pointer to the byte after the memory written at @p is * returned. */ u8 *put_resource_entry(u8 *p, const struct resource_entry *entry) { p = put_u56(p, entry->size); p = put_u8(p, entry->flags); p = put_u64(p, entry->offset); p = put_u64(p, entry->original_size); return p; } #ifdef WITH_FUSE static FILE *wim_get_fp(WIMStruct *w) { pthread_mutex_lock(&w->fp_tab_mutex); FILE *fp; wimlib_assert(w->filename != NULL); for (size_t i = 0; i < w->num_allocated_fps; i++) { if (w->fp_tab[i]) { fp = w->fp_tab[i]; w->fp_tab[i] = NULL; goto out; } } DEBUG("Opening extra file descriptor to `%s'", w->filename); fp = fopen(w->filename, "rb"); if (!fp) ERROR_WITH_ERRNO("Failed to open `%s'", w->filename); out: pthread_mutex_unlock(&w->fp_tab_mutex); return fp; } static int wim_release_fp(WIMStruct *w, FILE *fp) { int ret = 0; FILE **fp_tab; pthread_mutex_lock(&w->fp_tab_mutex); for (size_t i = 0; i < w->num_allocated_fps; i++) { if (w->fp_tab[i] == NULL) { w->fp_tab[i] = fp; goto out; } } fp_tab = REALLOC(w->fp_tab, sizeof(FILE*) * (w->num_allocated_fps + 4)); if (!fp_tab) { ret = WIMLIB_ERR_NOMEM; goto out; } w->fp_tab = fp_tab; memset(&w->fp_tab[w->num_allocated_fps], 0, 4 * sizeof(FILE*)); w->fp_tab[w->num_allocated_fps] = fp; w->num_allocated_fps += 4; out: pthread_mutex_unlock(&w->fp_tab_mutex); return ret; } #endif /* * Reads some data from the resource corresponding to a WIM lookup table entry. * * @lte: The WIM lookup table entry for the resource. * @buf: Buffer into which to write the data. * @size: Number of bytes to read. * @offset: Offset at which to start reading the resource. * * Returns zero on success, nonzero on failure. */ int read_wim_resource(const struct lookup_table_entry *lte, u8 buf[], size_t size, u64 offset, int flags) { int ctype; int ret = 0; FILE *fp; /* We shouldn't be allowing read over-runs in any part of the library. * */ if (flags & WIMLIB_RESOURCE_FLAG_RAW) wimlib_assert(offset + size <= lte->resource_entry.size); else wimlib_assert(offset + size <= lte->resource_entry.original_size); switch (lte->resource_location) { case RESOURCE_IN_WIM: /* The resource is in a WIM file, and its WIMStruct is given by * the lte->wim member. The resource may be either compressed * or uncompressed. */ wimlib_assert(lte->wim != NULL); #ifdef WITH_FUSE if (flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED) { fp = wim_get_fp(lte->wim); if (!fp) return WIMLIB_ERR_OPEN; } else #endif { wimlib_assert(!(flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED)); wimlib_assert(lte->wim->fp != NULL); fp = lte->wim->fp; } ctype = wim_resource_compression_type(lte); wimlib_assert(ctype != WIM_COMPRESSION_TYPE_NONE || (lte->resource_entry.original_size == lte->resource_entry.size)); if ((flags & WIMLIB_RESOURCE_FLAG_RAW) || ctype == WIM_COMPRESSION_TYPE_NONE) ret = read_uncompressed_resource(fp, lte->resource_entry.offset + offset, size, buf); else ret = read_compressed_resource(fp, lte->resource_entry.size, lte->resource_entry.original_size, lte->resource_entry.offset, ctype, size, offset, buf); #ifdef WITH_FUSE if (flags & WIMLIB_RESOURCE_FLAG_MULTITHREADED) { int ret2 = wim_release_fp(lte->wim, fp); if (ret == 0) ret = ret2; } #endif break; case RESOURCE_IN_STAGING_FILE: case RESOURCE_IN_FILE_ON_DISK: /* The resource is in some file on the external filesystem and * needs to be read uncompressed */ wimlib_assert(lte->file_on_disk); wimlib_assert(<e->file_on_disk == <e->staging_file_name); /* Use existing file pointer if available; otherwise open one * temporarily */ if (lte->file_on_disk_fp) { fp = lte->file_on_disk_fp; } else { fp = fopen(lte->file_on_disk, "rb"); if (!fp) { ERROR_WITH_ERRNO("Failed to open the file " "`%s'", lte->file_on_disk); ret = WIMLIB_ERR_OPEN; break; } } ret = read_uncompressed_resource(fp, offset, size, buf); if (fp != lte->file_on_disk_fp) fclose(fp); break; case RESOURCE_IN_ATTACHED_BUFFER: /* The resource is directly attached uncompressed in an * in-memory buffer. */ wimlib_assert(lte->attached_buffer != NULL); memcpy(buf, lte->attached_buffer + offset, size); break; #ifdef WITH_NTFS_3G case RESOURCE_IN_NTFS_VOLUME: wimlib_assert(lte->ntfs_loc != NULL); wimlib_assert(lte->attr != NULL); { if (lte->ntfs_loc->is_reparse_point) offset += 8; if (ntfs_attr_pread(lte->attr, offset, size, buf) != size) { ERROR_WITH_ERRNO("Error reading NTFS attribute " "at `%s'", lte->ntfs_loc->path_utf8); ret = WIMLIB_ERR_NTFS_3G; } break; } #endif default: wimlib_assert(0); ret = -1; break; } return ret; } /* * Reads all the data from the resource corresponding to a WIM lookup table * entry. * * @lte: The WIM lookup table entry for the resource. * @buf: Buffer into which to write the data. It must be at least * wim_resource_size(lte) bytes long. * * Returns 0 on success; nonzero on failure. */ int read_full_wim_resource(const struct lookup_table_entry *lte, u8 buf[], int flags) { return read_wim_resource(lte, buf, wim_resource_size(lte), 0, flags); } /* Like write_wim_resource(), but the resource is specified by a buffer of * uncompressed data rather a lookup table entry; also writes the SHA1 hash of * the buffer to @hash. */ static int write_wim_resource_from_buffer(const u8 *buf, u64 buf_size, FILE *out_fp, int out_ctype, struct resource_entry *out_res_entry, u8 hash[SHA1_HASH_SIZE]) { /* Set up a temporary lookup table entry to provide to * write_wim_resource(). */ struct lookup_table_entry lte; int ret; lte.resource_entry.flags = 0; lte.resource_entry.original_size = buf_size; lte.resource_entry.size = buf_size; lte.resource_entry.offset = 0; lte.resource_location = RESOURCE_IN_ATTACHED_BUFFER; lte.attached_buffer = (u8*)buf; zero_out_hash(lte.hash); ret = write_wim_resource(<e, out_fp, out_ctype, out_res_entry, 0); if (ret != 0) return ret; copy_hash(hash, lte.hash); return 0; } /* * Extracts the first @size bytes of the WIM resource specified by @lte to the * open file descriptor @fd. * * Returns 0 on success; nonzero on failure. */ int extract_wim_resource_to_fd(const struct lookup_table_entry *lte, int fd, u64 size) { u64 bytes_remaining = size; u8 buf[min(WIM_CHUNK_SIZE, bytes_remaining)]; u64 offset = 0; int ret = 0; u8 hash[SHA1_HASH_SIZE]; SHA_CTX ctx; sha1_init(&ctx); while (bytes_remaining) { u64 to_read = min(bytes_remaining, WIM_CHUNK_SIZE); ret = read_wim_resource(lte, buf, to_read, offset, 0); if (ret != 0) break; sha1_update(&ctx, buf, to_read); if (full_write(fd, buf, to_read) < to_read) { ERROR_WITH_ERRNO("Error extracting WIM resource"); return WIMLIB_ERR_WRITE; } bytes_remaining -= to_read; offset += to_read; } sha1_final(hash, &ctx); if (!hashes_equal(hash, lte->hash)) { ERROR("Invalid checksum on a WIM resource " "(detected when extracting to external file)"); ERROR("The following WIM resource is invalid:"); print_lookup_table_entry(lte); return WIMLIB_ERR_INVALID_RESOURCE_HASH; } return 0; } /* * Extracts the WIM resource specified by @lte to the open file descriptor @fd. * * Returns 0 on success; nonzero on failure. */ int extract_full_wim_resource_to_fd(const struct lookup_table_entry *lte, int fd) { return extract_wim_resource_to_fd(lte, fd, wim_resource_size(lte)); } /* * Copies the file resource specified by the lookup table entry @lte from the * input WIM to the output WIM that has its FILE * given by * ((WIMStruct*)wim)->out_fp. * * The output_resource_entry, out_refcnt, and part_number fields of @lte are * updated. * * Metadata resources are not copied (they are handled elsewhere for joining and * splitting). */ int copy_resource(struct lookup_table_entry *lte, void *wim) { WIMStruct *w = wim; int ret; if ((lte->resource_entry.flags & WIM_RESHDR_FLAG_METADATA) && !w->write_metadata) return 0; ret = write_wim_resource(lte, w->out_fp, wim_resource_compression_type(lte), <e->output_resource_entry, 0); if (ret != 0) return ret; lte->out_refcnt = lte->refcnt; lte->part_number = w->hdr.part_number; return 0; } /* * Reads the metadata metadata resource from the WIM file. The metadata * resource consists of the security data, followed by the directory entry for * the root directory, followed by all the other directory entries in the * filesystem. The subdir_offset field of each directory entry gives the start * of its child entries from the beginning of the metadata resource. An * end-of-directory is signaled by a directory entry of length '0', really of * length 8, because that's how long the 'length' field is. * * @fp: The FILE* for the input WIM file. * @wim_ctype: The compression type of the WIM file. * @imd: Pointer to the image metadata structure. Its `metadata_lte' * member specifies the lookup table entry for the metadata * resource. The rest of the image metadata entry will be filled * in by this function. * * @return: Zero on success, nonzero on failure. */ int read_metadata_resource(WIMStruct *w, struct image_metadata *imd) { u8 *buf; u32 dentry_offset; int ret; struct dentry *dentry; struct inode_table inode_tab; const struct lookup_table_entry *metadata_lte; u64 metadata_len; u64 metadata_offset; struct hlist_head inode_list; metadata_lte = imd->metadata_lte; metadata_len = wim_resource_size(metadata_lte); metadata_offset = metadata_lte->resource_entry.offset; DEBUG("Reading metadata resource: length = %"PRIu64", " "offset = %"PRIu64"", metadata_len, metadata_offset); /* There is no way the metadata resource could possibly be less than (8 * + WIM_DENTRY_DISK_SIZE) bytes, where the 8 is for security data (with * no security descriptors) and WIM_DENTRY_DISK_SIZE is for the root * dentry. */ if (metadata_len < 8 + WIM_DENTRY_DISK_SIZE) { ERROR("Expected at least %u bytes for the metadata resource", 8 + WIM_DENTRY_DISK_SIZE); return WIMLIB_ERR_INVALID_RESOURCE_SIZE; } if (sizeof(size_t) < 8 && metadata_len > 0xffffffff) { ERROR("Metadata resource is too large (%"PRIu64" bytes", metadata_len); return WIMLIB_ERR_INVALID_RESOURCE_SIZE; } /* Allocate memory for the uncompressed metadata resource. */ buf = MALLOC(metadata_len); if (!buf) { ERROR("Failed to allocate %"PRIu64" bytes for uncompressed " "metadata resource", metadata_len); return WIMLIB_ERR_NOMEM; } /* Read the metadata resource into memory. (It may be compressed.) */ ret = read_full_wim_resource(metadata_lte, buf, 0); if (ret != 0) goto out_free_buf; DEBUG("Finished reading metadata resource into memory."); /* The root directory entry starts after security data, aligned on an * 8-byte boundary within the metadata resource. * * The security data starts with a 4-byte integer giving its total * length, so if we round that up to an 8-byte boundary that gives us * the offset of the root dentry. * * Here we read the security data into a wim_security_data structure, * and if successful, go ahead and calculate the offset in the metadata * resource of the root dentry. */ wimlib_assert(imd->security_data == NULL); ret = read_security_data(buf, metadata_len, &imd->security_data); if (ret != 0) goto out_free_buf; dentry_offset = (imd->security_data->total_length + 7) & ~7; if (dentry_offset == 0) { ERROR("Integer overflow while reading metadata resource"); ret = WIMLIB_ERR_INVALID_SECURITY_DATA; goto out_free_security_data; } /* Allocate memory for the root dentry and read it into memory */ dentry = MALLOC(sizeof(struct dentry)); if (!dentry) { ERROR("Failed to allocate %zu bytes for root dentry", sizeof(struct dentry)); ret = WIMLIB_ERR_NOMEM; goto out_free_security_data; } ret = read_dentry(buf, metadata_len, dentry_offset, dentry); /* This is the root dentry, so set its parent to itself. */ dentry->parent = dentry; if (ret != 0) goto out_free_dentry_tree; inode_add_dentry(dentry, dentry->d_inode); /* Now read the entire directory entry tree into memory. */ DEBUG("Reading dentry tree"); ret = read_dentry_tree(buf, metadata_len, dentry); if (ret != 0) goto out_free_dentry_tree; /* Calculate the full paths in the dentry tree. */ DEBUG("Calculating dentry full paths"); ret = for_dentry_in_tree(dentry, calculate_dentry_full_path, NULL); if (ret != 0) goto out_free_dentry_tree; /* Build hash table that maps hard link group IDs to dentry sets */ DEBUG("Building link group table"); ret = init_inode_table(&inode_tab, 9001); if (ret != 0) goto out_free_dentry_tree; for_dentry_in_tree(dentry, inode_table_insert, &inode_tab); DEBUG("Fixing inconsistencies in the hard link groups"); ret = fix_inodes(&inode_tab, &inode_list); destroy_inode_table(&inode_tab); if (ret != 0) goto out_free_dentry_tree; DEBUG("Running miscellaneous verifications on the dentry tree"); for_lookup_table_entry(w->lookup_table, lte_zero_real_refcnt, NULL); ret = for_dentry_in_tree(dentry, verify_dentry, w); if (ret != 0) goto out_free_dentry_tree; DEBUG("Done reading image metadata"); imd->root_dentry = dentry; imd->inode_list = inode_list; goto out_free_buf; out_free_dentry_tree: free_dentry_tree(dentry, NULL); out_free_security_data: free_security_data(imd->security_data); imd->security_data = NULL; out_free_buf: FREE(buf); return ret; } /* Write the metadata resource for the current WIM image. */ int write_metadata_resource(WIMStruct *w) { u8 *buf; u8 *p; int ret; u64 subdir_offset; struct dentry *root; struct lookup_table_entry *lte; u64 metadata_original_size; const struct wim_security_data *sd; DEBUG("Writing metadata resource for image %d", w->current_image); root = wim_root_dentry(w); sd = wim_security_data(w); /* We do not allow the security data pointer to be NULL, although it may * point to an empty security data with no entries. */ wimlib_assert(root != NULL); wimlib_assert(sd != NULL); /* Offset of first child of the root dentry. It's equal to: * - The total length of the security data, rounded to the next 8-byte * boundary, * - plus the total length of the root dentry, * - plus 8 bytes for an end-of-directory entry following the root * dentry (shouldn't really be needed, but just in case...) */ subdir_offset = ((sd->total_length + 7) & ~7) + dentry_correct_total_length(root) + 8; /* Calculate the subdirectory offsets for the entire dentry tree. */ calculate_subdir_offsets(root, &subdir_offset); /* Total length of the metadata resource (uncompressed) */ metadata_original_size = subdir_offset; /* Allocate a buffer to contain the uncompressed metadata resource */ buf = MALLOC(metadata_original_size); if (!buf) { ERROR("Failed to allocate %"PRIu64" bytes for " "metadata resource", metadata_original_size); return WIMLIB_ERR_NOMEM; } /* Write the security data into the resource buffer */ p = write_security_data(sd, buf); /* Write the dentry tree into the resource buffer */ p = write_dentry_tree(root, p); /* We MUST have exactly filled the buffer; otherwise we calculated its * size incorrectly or wrote the data incorrectly. */ wimlib_assert(p - buf == metadata_original_size); /* Get the lookup table entry for the metadata resource so we can update * it. */ lte = wim_metadata_lookup_table_entry(w); wimlib_assert(lte != NULL); /* Write the metadata resource to the output WIM using the proper * compression type. The lookup table entry for the metadata resource * is updated. */ ret = write_wim_resource_from_buffer(buf, metadata_original_size, w->out_fp, wimlib_get_compression_type(w), <e->output_resource_entry, lte->hash); if (ret != 0) goto out; /* It's very likely the SHA1 message digest of the metadata resource * changed, so re-insert the lookup table entry into the lookup table. * * We do not check for other lookup table entries having the same SHA1 * message digest. It's possible for 2 absolutely identical images to * be added, therefore causing 2 identical metadata resources to be in * the WIM. However, in this case, it's expected for 2 separate lookup * table entries to be created, even though this doesn't make a whole * lot of sense since they will share the same SHA1 message digest. * */ lookup_table_unlink(w->lookup_table, lte); lookup_table_insert(w->lookup_table, lte); wimlib_assert(lte->out_refcnt == 0); lte->out_refcnt = 1; /* Make sure that the resource entry is written marked with the metadata * flag. */ lte->output_resource_entry.flags |= WIM_RESHDR_FLAG_METADATA; out: /* All the data has been written to the new WIM; no need for the buffer * anymore */ FREE(buf); return ret; }