6 * Copyright (C) 2012, 2013 Eric Biggers
8 * This file is free software; you can redistribute it and/or modify it under
9 * the terms of the GNU Lesser General Public License as published by the Free
10 * Software Foundation; either version 3 of the License, or (at your option) any
13 * This file is distributed in the hope that it will be useful, but WITHOUT
14 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
15 * FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
18 * You should have received a copy of the GNU Lesser General Public License
19 * along with this file; if not, see http://www.gnu.org/licenses/.
26 #include "wimlib/assert.h"
27 #include "wimlib/blob_table.h"
28 #include "wimlib/dentry.h"
29 #include "wimlib/error.h"
30 #include "wimlib/metadata.h"
31 #include "wimlib/resource.h"
32 #include "wimlib/security.h"
33 #include "wimlib/write.h"
35 /* Fix the security ID for every inode to be either -1 or in bounds. */
37 fix_security_ids(struct wim_image_metadata *imd, const u32 num_entries)
39 struct wim_inode *inode;
40 unsigned long invalid_count = 0;
42 image_for_each_inode(inode, imd) {
43 if ((u32)inode->i_security_id >= num_entries) {
44 if (inode->i_security_id >= 0)
46 inode->i_security_id = -1;
50 WARNING("%lu inodes had invalid security IDs", invalid_count);
54 * Reads and parses a metadata resource for an image in the WIM file.
57 * Pointer to the image metadata structure for the image whose metadata
58 * resource we are reading. Its `metadata_blob' member specifies the blob
59 * table entry for the metadata resource. The rest of the image metadata
60 * entry will be filled in by this function.
63 * WIMLIB_ERR_SUCCESS (0)
64 * WIMLIB_ERR_INVALID_METADATA_RESOURCE
67 * WIMLIB_ERR_UNEXPECTED_END_OF_FILE
68 * WIMLIB_ERR_DECOMPRESSION
71 read_metadata_resource(struct wim_image_metadata *imd)
73 const struct blob_descriptor *metadata_blob;
76 struct wim_security_data *sd;
77 struct wim_dentry *root;
79 metadata_blob = imd->metadata_blob;
81 DEBUG("Reading metadata resource (size=%"PRIu64").", metadata_blob->size);
83 /* Read the metadata resource into memory. (It may be compressed.) */
84 ret = read_blob_into_alloc_buf(metadata_blob, &buf);
88 /* Checksum the metadata resource. */
89 if (!metadata_blob->dont_check_metadata_hash) {
90 u8 hash[SHA1_HASH_SIZE];
92 sha1_buffer(buf, metadata_blob->size, hash);
93 if (!hashes_equal(metadata_blob->hash, hash)) {
94 ERROR("Metadata resource is corrupted "
95 "(invalid SHA-1 message digest)!");
96 ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
101 /* Parse the metadata resource.
103 * Notes: The metadata resource consists of the security data, followed
104 * by the directory entry for the root directory, followed by all the
105 * other directory entries in the filesystem. The subdir_offset field
106 * of each directory entry gives the start of its child entries from the
107 * beginning of the metadata resource. An end-of-directory is signaled
108 * by a directory entry of length '0', really of length 8, because
109 * that's how long the 'length' field is. */
111 ret = read_wim_security_data(buf, metadata_blob->size, &sd);
115 ret = read_dentry_tree(buf, metadata_blob->size, sd->total_length, &root);
117 goto out_free_security_data;
119 /* We have everything we need from the buffer now. */
123 /* Calculate and validate inodes. */
125 ret = dentry_tree_fix_inodes(root, &imd->inode_list);
127 goto out_free_dentry_tree;
129 fix_security_ids(imd, sd->num_entries);
131 /* Success; fill in the image_metadata structure. */
132 imd->root_dentry = root;
133 imd->security_data = sd;
134 INIT_LIST_HEAD(&imd->unhashed_blobs);
135 DEBUG("Done parsing metadata resource.");
138 out_free_dentry_tree:
139 free_dentry_tree(root, NULL);
140 out_free_security_data:
141 free_wim_security_data(sd);
148 recalculate_security_data_length(struct wim_security_data *sd)
150 u32 total_length = sizeof(u64) * sd->num_entries + 2 * sizeof(u32);
151 for (u32 i = 0; i < sd->num_entries; i++)
152 total_length += sd->sizes[i];
153 sd->total_length = ALIGN(total_length, 8);
157 prepare_metadata_resource(WIMStruct *wim, int image,
158 u8 **buf_ret, size_t *len_ret)
164 struct wim_dentry *root;
166 struct wim_security_data *sd;
167 struct wim_image_metadata *imd;
169 DEBUG("Preparing metadata resource for image %d", image);
171 ret = select_wim_image(wim, image);
175 imd = wim->image_metadata[image - 1];
177 root = imd->root_dentry;
178 sd = imd->security_data;
181 /* Empty image; create a dummy root. */
182 ret = new_filler_directory(&root);
185 imd->root_dentry = root;
188 /* The offset of the first child of the root dentry is equal to the
189 * total length of the security data, plus the total length of the root
190 * dentry, plus 8 bytes for an end-of-directory entry following the root
191 * dentry (shouldn't really be needed, but just in case...) */
192 recalculate_security_data_length(sd);
193 subdir_offset = sd->total_length + dentry_out_total_length(root) + 8;
195 /* Calculate the subdirectory offsets for the entire dentry tree. */
196 calculate_subdir_offsets(root, &subdir_offset);
198 /* Total length of the metadata resource (uncompressed). */
201 /* Allocate a buffer to contain the uncompressed metadata resource. */
203 if (likely(len == subdir_offset))
206 ERROR("Failed to allocate %"PRIu64" bytes for "
207 "metadata resource", subdir_offset);
208 return WIMLIB_ERR_NOMEM;
211 /* Write the security data into the resource buffer. */
212 p = write_wim_security_data(sd, buf);
214 /* Write the dentry tree into the resource buffer. */
215 p = write_dentry_tree(root, p);
217 /* We MUST have exactly filled the buffer; otherwise we calculated its
218 * size incorrectly or wrote the data incorrectly. */
219 wimlib_assert(p - buf == len);
227 write_metadata_resource(WIMStruct *wim, int image, int write_resource_flags)
232 struct wim_image_metadata *imd;
234 ret = prepare_metadata_resource(wim, image, &buf, &len);
238 imd = wim->image_metadata[image - 1];
240 /* Write the metadata resource to the output WIM using the proper
241 * compression type, in the process updating the blob descriptor for the
242 * metadata resource. */
243 ret = write_wim_resource_from_buffer(buf,
247 wim->out_compression_type,
249 &imd->metadata_blob->out_reshdr,
250 imd->metadata_blob->hash,
251 write_resource_flags);
253 /* Original checksum was overridden; set a flag so it isn't used. */
254 imd->metadata_blob->dont_check_metadata_hash = 1;