6 * Copyright (C) 2012, 2013 Biggers
8 * This file is part of wimlib, a library for working with WIM files.
10 * wimlib is free software; you can redistribute it and/or modify it under the
11 * terms of the GNU General Public License as published by the Free Software
12 * Foundation; either version 3 of the License, or (at your option) any later
15 * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
16 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
17 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License along with
20 * wimlib; if not, see http://www.gnu.org/licenses/.
23 #include "wimlib_internal.h"
25 #include "lookup_table.h"
28 * Reads the metadata metadata resource from the WIM file. The metadata
29 * resource consists of the security data, followed by the directory entry for
30 * the root directory, followed by all the other directory entries in the
31 * filesystem. The subdir_offset field of each directory entry gives the start
32 * of its child entries from the beginning of the metadata resource. An
33 * end-of-directory is signaled by a directory entry of length '0', really of
34 * length 8, because that's how long the 'length' field is.
36 * @fp: The FILE* for the input WIM file.
37 * @wim_ctype: The compression type of the WIM file.
38 * @imd: Pointer to the image metadata structure. Its `metadata_lte'
39 * member specifies the lookup table entry for the metadata
40 * resource. The rest of the image metadata entry will be filled
41 * in by this function.
43 * @return: Zero on success, nonzero on failure.
45 int read_metadata_resource(WIMStruct *w, struct wim_image_metadata *imd)
50 struct wim_dentry *dentry;
51 const struct wim_lookup_table_entry *metadata_lte;
53 struct hlist_head inode_list;
55 metadata_lte = imd->metadata_lte;
56 metadata_len = wim_resource_size(metadata_lte);
58 DEBUG("Reading metadata resource: length = %"PRIu64", "
59 "offset = %"PRIu64"", metadata_len,
60 metadata_lte->resource_entry.offset);
62 /* There is no way the metadata resource could possibly be less than (8
63 * + WIM_DENTRY_DISK_SIZE) bytes, where the 8 is for security data (with
64 * no security descriptors) and WIM_DENTRY_DISK_SIZE is for the root
66 if (metadata_len < 8 + WIM_DENTRY_DISK_SIZE) {
67 ERROR("Expected at least %u bytes for the metadata resource",
68 8 + WIM_DENTRY_DISK_SIZE);
69 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
72 if (sizeof(size_t) < 8 && metadata_len > 0xffffffff) {
73 ERROR("Metadata resource is too large (%"PRIu64" bytes",
75 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
78 /* Allocate memory for the uncompressed metadata resource. */
79 buf = MALLOC(metadata_len);
82 ERROR("Failed to allocate %"PRIu64" bytes for uncompressed "
83 "metadata resource", metadata_len);
84 return WIMLIB_ERR_NOMEM;
87 /* Read the metadata resource into memory. (It may be compressed.) */
88 ret = read_full_wim_resource(metadata_lte, buf, 0);
92 DEBUG("Finished reading metadata resource into memory.");
94 /* The root directory entry starts after security data, aligned on an
95 * 8-byte boundary within the metadata resource.
97 * The security data starts with a 4-byte integer giving its total
98 * length, so if we round that up to an 8-byte boundary that gives us
99 * the offset of the root dentry.
101 * Here we read the security data into a wim_security_data structure,
102 * and if successful, go ahead and calculate the offset in the metadata
103 * resource of the root dentry. */
105 wimlib_assert(imd->security_data == NULL);
106 ret = read_security_data(buf, metadata_len, &imd->security_data);
110 dentry_offset = (imd->security_data->total_length + 7) & ~7;
112 if (dentry_offset == 0) {
113 ERROR("Integer overflow while reading metadata resource");
114 ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
115 goto out_free_security_data;
118 DEBUG("Reading root dentry");
120 /* Allocate memory for the root dentry and read it into memory */
121 dentry = MALLOC(sizeof(struct wim_dentry));
123 ERROR("Failed to allocate %zu bytes for root dentry",
124 sizeof(struct wim_dentry));
125 ret = WIMLIB_ERR_NOMEM;
126 goto out_free_security_data;
129 ret = read_dentry(buf, metadata_len, dentry_offset, dentry);
131 /* This is the root dentry, so set its parent to itself. */
132 dentry->parent = dentry;
134 if (ret == 0 && dentry->length == 0) {
135 ERROR("Metadata resource cannot begin with end-of-directory entry!");
136 ret = WIMLIB_ERR_INVALID_DENTRY;
141 goto out_free_security_data;
144 inode_add_dentry(dentry, dentry->d_inode);
146 /* Now read the entire directory entry tree into memory. */
147 DEBUG("Reading dentry tree");
148 ret = read_dentry_tree(buf, metadata_len, dentry);
150 goto out_free_dentry_tree;
152 /* Calculate the full paths in the dentry tree. */
153 DEBUG("Calculating dentry full paths");
154 ret = for_dentry_in_tree(dentry, calculate_dentry_full_path, NULL);
156 goto out_free_dentry_tree;
158 /* Build hash table that maps hard link group IDs to dentry sets */
159 ret = dentry_tree_fix_inodes(dentry, &inode_list);
161 goto out_free_dentry_tree;
163 if (!w->all_images_verified) {
164 DEBUG("Running miscellaneous verifications on the dentry tree");
165 for_lookup_table_entry(w->lookup_table, lte_zero_real_refcnt, NULL);
166 ret = for_dentry_in_tree(dentry, verify_dentry, w);
168 goto out_free_dentry_tree;
171 DEBUG("Done reading image metadata");
173 imd->root_dentry = dentry;
174 imd->inode_list = inode_list;
175 if (imd->inode_list.first)
176 imd->inode_list.first->pprev = &imd->inode_list.first;
178 out_free_dentry_tree:
179 free_dentry_tree(dentry, NULL);
180 out_free_security_data:
181 free_security_data(imd->security_data);
182 imd->security_data = NULL;
188 static void recalculate_security_data_length(struct wim_security_data *sd)
190 u32 total_length = sizeof(u64) * sd->num_entries + 2 * sizeof(u32);
191 for (u32 i = 0; i < sd->num_entries; i++)
192 total_length += sd->sizes[i];
193 sd->total_length = total_length;
196 /* Like write_wim_resource(), but the resource is specified by a buffer of
197 * uncompressed data rather a lookup table entry; also writes the SHA1 hash of
198 * the buffer to @hash. */
199 static int write_wim_resource_from_buffer(const u8 *buf, u64 buf_size,
200 FILE *out_fp, int out_ctype,
201 struct resource_entry *out_res_entry,
202 u8 hash[SHA1_HASH_SIZE])
204 /* Set up a temporary lookup table entry to provide to
205 * write_wim_resource(). */
206 struct wim_lookup_table_entry lte;
208 lte.resource_entry.flags = 0;
209 lte.resource_entry.original_size = buf_size;
210 lte.resource_entry.size = buf_size;
211 lte.resource_entry.offset = 0;
212 lte.resource_location = RESOURCE_IN_ATTACHED_BUFFER;
213 lte.attached_buffer = (u8*)buf;
215 zero_out_hash(lte.hash);
216 ret = write_wim_resource(<e, out_fp, out_ctype, out_res_entry, 0);
219 copy_hash(hash, lte.hash);
223 /* Write the metadata resource for the current WIM image. */
224 int write_metadata_resource(WIMStruct *w)
230 struct wim_dentry *root;
231 struct wim_lookup_table_entry *lte;
232 u64 metadata_original_size;
233 struct wim_security_data *sd;
235 DEBUG("Writing metadata resource for image %d (offset = %"PRIu64")",
236 w->current_image, ftello(w->out_fp));
238 root = wim_root_dentry(w);
239 sd = wim_security_data(w);
241 /* Offset of first child of the root dentry. It's equal to:
242 * - The total length of the security data, rounded to the next 8-byte
244 * - plus the total length of the root dentry,
245 * - plus 8 bytes for an end-of-directory entry following the root
246 * dentry (shouldn't really be needed, but just in case...)
248 recalculate_security_data_length(sd);
249 subdir_offset = (((u64)sd->total_length + 7) & ~7) +
250 dentry_correct_total_length(root) + 8;
252 /* Calculate the subdirectory offsets for the entire dentry tree. */
253 calculate_subdir_offsets(root, &subdir_offset);
255 /* Total length of the metadata resource (uncompressed) */
256 metadata_original_size = subdir_offset;
258 /* Allocate a buffer to contain the uncompressed metadata resource */
259 buf = MALLOC(metadata_original_size);
261 ERROR("Failed to allocate %"PRIu64" bytes for "
262 "metadata resource", metadata_original_size);
263 return WIMLIB_ERR_NOMEM;
266 /* Write the security data into the resource buffer */
267 p = write_security_data(sd, buf);
269 /* Write the dentry tree into the resource buffer */
270 p = write_dentry_tree(root, p);
272 /* We MUST have exactly filled the buffer; otherwise we calculated its
273 * size incorrectly or wrote the data incorrectly. */
274 wimlib_assert(p - buf == metadata_original_size);
276 /* Get the lookup table entry for the metadata resource so we can update
278 lte = w->image_metadata[w->current_image - 1].metadata_lte;
280 /* Write the metadata resource to the output WIM using the proper
281 * compression type. The lookup table entry for the metadata resource
283 ret = write_wim_resource_from_buffer(buf, metadata_original_size,
285 wimlib_get_compression_type(w),
286 <e->output_resource_entry,
291 /* It's very likely the SHA1 message digest of the metadata resource
292 * changed, so re-insert the lookup table entry into the lookup table.
294 * We do not check for other lookup table entries having the same SHA1
295 * message digest. It's possible for 2 absolutely identical images to
296 * be added, therefore causing 2 identical metadata resources to be in
297 * the WIM. However, in this case, it's expected for 2 separate lookup
298 * table entries to be created, even though this doesn't make a whole
299 * lot of sense since they will share the same SHA1 message digest.
301 lookup_table_unlink(w->lookup_table, lte);
302 lookup_table_insert(w->lookup_table, lte);
305 /* Make sure that the lookup table entry for this metadata resource is
306 * marked with the metadata flag. */
307 lte->output_resource_entry.flags |= WIM_RESHDR_FLAG_METADATA;
309 /* All the data has been written to the new WIM; no need for the buffer