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;
55 metadata_lte = imd->metadata_lte;
56 metadata_len = wim_resource_size(metadata_lte);
58 DEBUG("Reading metadata resource: original_size = %"PRIu64", "
59 "size = %"PRIu64", offset = %"PRIu64"",
60 metadata_lte->resource_entry.original_size,
61 metadata_lte->resource_entry.size,
62 metadata_lte->resource_entry.offset);
64 /* There is no way the metadata resource could possibly be less than (8
65 * + WIM_DENTRY_DISK_SIZE) bytes, where the 8 is for security data (with
66 * no security descriptors) and WIM_DENTRY_DISK_SIZE is for the root
68 if (metadata_len < 8 + WIM_DENTRY_DISK_SIZE) {
69 ERROR("Expected at least %u bytes for the metadata resource",
70 8 + WIM_DENTRY_DISK_SIZE);
71 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
74 if (sizeof(size_t) < 8 && metadata_len > 0xffffffff) {
75 ERROR("Metadata resource is too large (%"PRIu64" bytes",
77 return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
80 /* Allocate memory for the uncompressed metadata resource. */
81 buf = MALLOC(metadata_len);
84 ERROR("Failed to allocate %"PRIu64" bytes for uncompressed "
85 "metadata resource", metadata_len);
86 return WIMLIB_ERR_NOMEM;
89 /* Read the metadata resource into memory. (It may be compressed.) */
90 ret = read_full_resource_into_buf(metadata_lte, buf);
94 DEBUG("Finished reading metadata resource into memory.");
96 /* The root directory entry starts after security data, aligned on an
97 * 8-byte boundary within the metadata resource.
99 * The security data starts with a 4-byte integer giving its total
100 * length, so if we round that up to an 8-byte boundary that gives us
101 * the offset of the root dentry.
103 * Here we read the security data into a wim_security_data structure,
104 * and if successful, go ahead and calculate the offset in the metadata
105 * resource of the root dentry. */
107 wimlib_assert(imd->security_data == NULL);
108 ret = read_security_data(buf, metadata_len, &imd->security_data);
112 dentry_offset = (imd->security_data->total_length + 7) & ~7;
114 if (dentry_offset == 0) {
115 ERROR("Integer overflow while reading metadata resource");
116 ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
117 goto out_free_security_data;
120 DEBUG("Reading root dentry");
122 /* Allocate memory for the root dentry and read it into memory */
123 dentry = MALLOC(sizeof(struct wim_dentry));
125 ERROR("Failed to allocate %zu bytes for root dentry",
126 sizeof(struct wim_dentry));
127 ret = WIMLIB_ERR_NOMEM;
128 goto out_free_security_data;
131 ret = read_dentry(buf, metadata_len, dentry_offset, dentry);
133 /* This is the root dentry, so set its parent to itself. */
134 dentry->parent = dentry;
136 if (ret == 0 && dentry->length == 0) {
137 ERROR("Metadata resource cannot begin with end-of-directory entry!");
138 ret = WIMLIB_ERR_INVALID_DENTRY;
143 goto out_free_security_data;
146 inode_add_dentry(dentry, dentry->d_inode);
148 /* Now read the entire directory entry tree into memory. */
149 DEBUG("Reading dentry tree");
150 ret = read_dentry_tree(buf, metadata_len, dentry);
152 goto out_free_dentry_tree;
154 /* Build hash table that maps hard link group IDs to dentry sets */
155 ret = dentry_tree_fix_inodes(dentry, &imd->inode_list);
157 goto out_free_dentry_tree;
159 if (!w->all_images_verified) {
160 DEBUG("Running miscellaneous verifications on the dentry tree");
161 for_lookup_table_entry(w->lookup_table, lte_zero_real_refcnt, NULL);
162 ret = for_dentry_in_tree(dentry, verify_dentry, w);
164 goto out_free_dentry_tree;
167 DEBUG("Done reading image metadata");
169 imd->root_dentry = dentry;
170 INIT_LIST_HEAD(&imd->unhashed_streams);
172 out_free_dentry_tree:
173 free_dentry_tree(dentry, NULL);
174 out_free_security_data:
175 free_security_data(imd->security_data);
176 imd->security_data = NULL;
183 recalculate_security_data_length(struct wim_security_data *sd)
185 u32 total_length = sizeof(u64) * sd->num_entries + 2 * sizeof(u32);
186 for (u32 i = 0; i < sd->num_entries; i++)
187 total_length += sd->sizes[i];
188 sd->total_length = total_length;
191 /* Like write_wim_resource(), but the resource is specified by a buffer of
192 * uncompressed data rather a lookup table entry; also writes the SHA1 hash of
193 * the buffer to @hash. */
195 write_wim_resource_from_buffer(const void *buf, size_t buf_size,
196 filedes_t out_fd, int out_ctype,
197 struct resource_entry *out_res_entry,
198 u8 hash[SHA1_HASH_SIZE])
200 /* Set up a temporary lookup table entry to provide to
201 * write_wim_resource(). */
202 struct wim_lookup_table_entry lte;
204 lte.resource_location = RESOURCE_IN_ATTACHED_BUFFER;
205 lte.attached_buffer = (void*)buf;
206 lte.resource_entry.original_size = buf_size;
207 lte.resource_entry.flags = 0;
209 ret = write_wim_resource(<e, out_fd, out_ctype, out_res_entry, 0);
211 copy_hash(hash, lte.hash);
215 /* Write the metadata resource for the current WIM image. */
217 write_metadata_resource(WIMStruct *w)
223 struct wim_dentry *root;
224 struct wim_lookup_table_entry *lte;
225 u64 metadata_original_size;
226 struct wim_security_data *sd;
228 wimlib_assert(w->out_fd != INVALID_FILEDES);
229 wimlib_assert(w->current_image != WIMLIB_NO_IMAGE);
231 DEBUG("Writing metadata resource for image %d (offset = %"PRIu64")",
232 w->current_image, filedes_offset(w->out_fd));
235 root = wim_root_dentry(w);
236 sd = wim_security_data(w);
238 /* Offset of first child of the root dentry. It's equal to:
239 * - The total length of the security data, rounded to the next 8-byte
241 * - plus the total length of the root dentry,
242 * - plus 8 bytes for an end-of-directory entry following the root
243 * dentry (shouldn't really be needed, but just in case...)
245 recalculate_security_data_length(sd);
246 subdir_offset = (((u64)sd->total_length + 7) & ~7) +
247 dentry_correct_total_length(root) + 8;
249 /* Calculate the subdirectory offsets for the entire dentry tree. */
250 calculate_subdir_offsets(root, &subdir_offset);
252 /* Total length of the metadata resource (uncompressed) */
253 metadata_original_size = subdir_offset;
255 /* Allocate a buffer to contain the uncompressed metadata resource */
256 buf = MALLOC(metadata_original_size);
258 ERROR("Failed to allocate %"PRIu64" bytes for "
259 "metadata resource", metadata_original_size);
260 return WIMLIB_ERR_NOMEM;
263 /* Write the security data into the resource buffer */
264 p = write_security_data(sd, buf);
266 /* Write the dentry tree into the resource buffer */
267 p = write_dentry_tree(root, p);
269 /* We MUST have exactly filled the buffer; otherwise we calculated its
270 * size incorrectly or wrote the data incorrectly. */
271 wimlib_assert(p - buf == metadata_original_size);
273 /* Get the lookup table entry for the metadata resource so we can update
275 lte = wim_get_current_image_metadata(w)->metadata_lte;
277 /* Write the metadata resource to the output WIM using the proper
278 * compression type. The lookup table entry for the metadata resource
280 ret = write_wim_resource_from_buffer(buf, metadata_original_size,
282 wimlib_get_compression_type(w),
283 <e->output_resource_entry,
285 /* Note that although the SHA1 message digest of the metadata resource
286 * is very likely to have changed, the corresponding lookup table entry
287 * is not actually located in the hash table, so it need not be
288 * re-inserted in the hash table. */
290 /* All the data has been written to the new WIM; no need for the buffer