6 * Copyright (C) 2012, 2013 Eric 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.
46 read_metadata_resource(WIMStruct *w, struct wim_image_metadata *imd)
51 struct wim_dentry *dentry;
52 const struct wim_lookup_table_entry *metadata_lte;
54 struct hlist_head inode_list;
56 metadata_lte = imd->metadata_lte;
57 metadata_len = wim_resource_size(metadata_lte);
59 DEBUG("Reading metadata resource: length = %"PRIu64", "
60 "offset = %"PRIu64"", metadata_len,
61 metadata_lte->resource_entry.offset);
63 /* There is no way the metadata resource could possibly be less than (8
64 * + WIM_DENTRY_DISK_SIZE) bytes, where the 8 is for security data (with
65 * no security descriptors) and WIM_DENTRY_DISK_SIZE is for the root
67 if (metadata_len < 8 + WIM_DENTRY_DISK_SIZE) {
68 ERROR("Expected at least %u bytes for the metadata resource",
69 8 + WIM_DENTRY_DISK_SIZE);
70 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
73 if (sizeof(size_t) < 8 && metadata_len > 0xffffffff) {
74 ERROR("Metadata resource is too large (%"PRIu64" bytes",
76 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
79 /* Allocate memory for the uncompressed metadata resource. */
80 buf = MALLOC(metadata_len);
83 ERROR("Failed to allocate %"PRIu64" bytes for uncompressed "
84 "metadata resource", metadata_len);
85 return WIMLIB_ERR_NOMEM;
88 /* Read the metadata resource into memory. (It may be compressed.) */
89 ret = read_full_wim_resource(metadata_lte, buf, 0);
93 DEBUG("Finished reading metadata resource into memory.");
95 /* The root directory entry starts after security data, aligned on an
96 * 8-byte boundary within the metadata resource.
98 * The security data starts with a 4-byte integer giving its total
99 * length, so if we round that up to an 8-byte boundary that gives us
100 * the offset of the root dentry.
102 * Here we read the security data into a wim_security_data structure,
103 * and if successful, go ahead and calculate the offset in the metadata
104 * resource of the root dentry. */
106 wimlib_assert(imd->security_data == NULL);
107 ret = read_security_data(buf, metadata_len, &imd->security_data);
111 dentry_offset = (imd->security_data->total_length + 7) & ~7;
113 if (dentry_offset == 0) {
114 ERROR("Integer overflow while reading metadata resource");
115 ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
116 goto out_free_security_data;
119 DEBUG("Reading root dentry");
121 /* Allocate memory for the root dentry and read it into memory */
122 dentry = MALLOC(sizeof(struct wim_dentry));
124 ERROR("Failed to allocate %zu bytes for root dentry",
125 sizeof(struct wim_dentry));
126 ret = WIMLIB_ERR_NOMEM;
127 goto out_free_security_data;
130 ret = read_dentry(buf, metadata_len, dentry_offset, dentry);
132 /* This is the root dentry, so set its parent to itself. */
133 dentry->parent = dentry;
135 if (ret == 0 && dentry->length == 0) {
136 ERROR("Metadata resource cannot begin with end-of-directory entry!");
137 ret = WIMLIB_ERR_INVALID_DENTRY;
142 goto out_free_security_data;
145 inode_add_dentry(dentry, dentry->d_inode);
147 /* Now read the entire directory entry tree into memory. */
148 DEBUG("Reading dentry tree");
149 ret = read_dentry_tree(buf, metadata_len, dentry);
151 goto out_free_dentry_tree;
153 /* Calculate the full paths in the dentry tree. */
154 DEBUG("Calculating dentry full paths");
155 ret = for_dentry_in_tree(dentry, calculate_dentry_full_path, NULL);
157 goto out_free_dentry_tree;
159 /* Build hash table that maps hard link group IDs to dentry sets */
160 ret = dentry_tree_fix_inodes(dentry, &inode_list);
162 goto out_free_dentry_tree;
164 if (!w->all_images_verified) {
165 DEBUG("Running miscellaneous verifications on the dentry tree");
166 for_lookup_table_entry(w->lookup_table, lte_zero_real_refcnt, NULL);
167 ret = for_dentry_in_tree(dentry, verify_dentry, w);
169 goto out_free_dentry_tree;
172 DEBUG("Done reading image metadata");
174 imd->root_dentry = dentry;
175 imd->inode_list = inode_list;
176 if (imd->inode_list.first)
177 imd->inode_list.first->pprev = &imd->inode_list.first;
179 out_free_dentry_tree:
180 free_dentry_tree(dentry, NULL);
181 out_free_security_data:
182 free_security_data(imd->security_data);
183 imd->security_data = NULL;
190 recalculate_security_data_length(struct wim_security_data *sd)
192 u32 total_length = sizeof(u64) * sd->num_entries + 2 * sizeof(u32);
193 for (u32 i = 0; i < sd->num_entries; i++)
194 total_length += sd->sizes[i];
195 sd->total_length = total_length;
198 /* Like write_wim_resource(), but the resource is specified by a buffer of
199 * uncompressed data rather a lookup table entry; also writes the SHA1 hash of
200 * the buffer to @hash. */
202 write_wim_resource_from_buffer(const u8 *buf, u64 buf_size,
203 FILE *out_fp, int out_ctype,
204 struct resource_entry *out_res_entry,
205 u8 hash[SHA1_HASH_SIZE])
207 /* Set up a temporary lookup table entry to provide to
208 * write_wim_resource(). */
209 struct wim_lookup_table_entry lte;
211 lte.resource_entry.flags = 0;
212 lte.resource_entry.original_size = buf_size;
213 lte.resource_entry.size = buf_size;
214 lte.resource_entry.offset = 0;
215 lte.resource_location = RESOURCE_IN_ATTACHED_BUFFER;
216 lte.attached_buffer = (void*)buf;
218 zero_out_hash(lte.hash);
219 ret = write_wim_resource(<e, out_fp, out_ctype, out_res_entry, 0);
222 copy_hash(hash, lte.hash);
226 /* Write the metadata resource for the current WIM image. */
228 write_metadata_resource(WIMStruct *w)
234 struct wim_dentry *root;
235 struct wim_lookup_table_entry *lte;
236 u64 metadata_original_size;
237 struct wim_security_data *sd;
239 wimlib_assert(w->out_fp != NULL);
240 wimlib_assert(w->current_image != WIMLIB_NO_IMAGE);
242 DEBUG("Writing metadata resource for image %d (offset = %"PRIu64")",
243 w->current_image, ftello(w->out_fp));
246 root = wim_root_dentry(w);
247 sd = wim_security_data(w);
249 /* Offset of first child of the root dentry. It's equal to:
250 * - The total length of the security data, rounded to the next 8-byte
252 * - plus the total length of the root dentry,
253 * - plus 8 bytes for an end-of-directory entry following the root
254 * dentry (shouldn't really be needed, but just in case...)
256 recalculate_security_data_length(sd);
257 subdir_offset = (((u64)sd->total_length + 7) & ~7) +
258 dentry_correct_total_length(root) + 8;
260 /* Calculate the subdirectory offsets for the entire dentry tree. */
261 calculate_subdir_offsets(root, &subdir_offset);
263 /* Total length of the metadata resource (uncompressed) */
264 metadata_original_size = subdir_offset;
266 /* Allocate a buffer to contain the uncompressed metadata resource */
267 buf = MALLOC(metadata_original_size);
269 ERROR("Failed to allocate %"PRIu64" bytes for "
270 "metadata resource", metadata_original_size);
271 return WIMLIB_ERR_NOMEM;
274 /* Write the security data into the resource buffer */
275 p = write_security_data(sd, buf);
277 /* Write the dentry tree into the resource buffer */
278 p = write_dentry_tree(root, p);
280 /* We MUST have exactly filled the buffer; otherwise we calculated its
281 * size incorrectly or wrote the data incorrectly. */
282 wimlib_assert(p - buf == metadata_original_size);
284 /* Get the lookup table entry for the metadata resource so we can update
286 lte = w->image_metadata[w->current_image - 1].metadata_lte;
288 /* Write the metadata resource to the output WIM using the proper
289 * compression type. The lookup table entry for the metadata resource
291 ret = write_wim_resource_from_buffer(buf, metadata_original_size,
293 wimlib_get_compression_type(w),
294 <e->output_resource_entry,
299 /* Note that although the SHA1 message digest of the metadata resource
300 * is very likely to have changed, the corresponding lookup table entry
301 * is not actually located in the hash table, so it need not be
302 * re-inserted in the hash table. */
304 lte->output_resource_entry.flags |= WIM_RESHDR_FLAG_METADATA;
306 /* All the data has been written to the new WIM; no need for the buffer