struct wim_security_data *sd;
struct link_group_table *lgt;
const struct lookup_table_entry *metadata_lte;
- const struct resource_entry *res_entry;
+ u64 metadata_len;
+ u64 metadata_offset;
metadata_lte = imd->metadata_lte;
- res_entry = &metadata_lte->resource_entry;
+ metadata_len = wim_resource_size(metadata_lte);
+ metadata_offset = metadata_lte->resource_entry.offset;
DEBUG("Reading metadata resource: length = %"PRIu64", "
- "offset = %"PRIu64"",
- res_entry->original_size, res_entry->offset);
-
- if (res_entry->original_size < 8) {
- ERROR("Expected at least 8 bytes for the metadata resource");
+ "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 %zu bytes for the metadata resource",
+ 8 + WIM_DENTRY_DISK_SIZE);
return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
}
/* Allocate memory for the uncompressed metadata resource. */
- buf = MALLOC(res_entry->original_size);
+ buf = MALLOC(metadata_len);
if (!buf) {
ERROR("Failed to allocate %"PRIu64" bytes for uncompressed "
- "metadata resource", res_entry->original_size);
+ "metadata resource", metadata_len);
return WIMLIB_ERR_NOMEM;
}
- /* Determine the compression type of the metadata resource. */
-
/* Read the metadata resource into memory. (It may be compressed.) */
ret = read_full_wim_resource(metadata_lte, buf);
if (ret != 0)
DEBUG("Finished reading metadata resource into memory.");
- /* The root directory entry starts after security data, on an 8-byte
- * aligned address.
+ /* 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. */
+ * 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. */
- /* Read the security data into a wim_security_data structure. */
- ret = read_security_data(buf, res_entry->original_size, &sd);
+ ret = read_security_data(buf, metadata_len, &sd);
if (ret != 0)
goto out_free_buf;
+ get_u32(buf, &dentry_offset);
+ if (dentry_offset == 0)
+ dentry_offset = 8;
+ dentry_offset = (dentry_offset + 7) & ~7;
+
+ /* 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",
ret = WIMLIB_ERR_NOMEM;
goto out_free_security_data;
}
-
- get_u32(buf, &dentry_offset);
- if (dentry_offset == 0)
- dentry_offset = 8;
- dentry_offset = (dentry_offset + 7) & ~7;
- ret = read_dentry(buf, res_entry->original_size, dentry_offset, dentry);
+ ret = read_dentry(buf, metadata_len, dentry_offset, dentry);
+
/* This is the root dentry, so set its pointers correctly. */
dentry->parent = dentry;
dentry->next = dentry;
if (ret != 0)
goto out_free_dentry_tree;
+ /* Now read the entire directory entry tree into memory. */
DEBUG("Reading dentry tree");
- /* Now read the entire directory entry tree. */
- ret = read_dentry_tree(buf, res_entry->original_size, dentry);
+ ret = read_dentry_tree(buf, metadata_len, dentry);
if (ret != 0)
goto out_free_dentry_tree;
- DEBUG("Calculating dentry full paths");
/* 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;
- DEBUG("Building link group table");
/* Build hash table that maps hard link group IDs to dentry sets */
+ DEBUG("Building link group table");
lgt = new_link_group_table(9001);
if (!lgt)
goto out_free_dentry_tree;
struct dentry *root;
struct lookup_table_entry *lte, *duplicate_lte;
u64 metadata_original_size;
-
- /*
- * We append 20 random bytes to the metadata resource so that we don't
- * have identical metadata resources if we happen to append exactly the
- * same image twice without any changes in timestamps. If this were to
- * happen, it would cause confusion about the number and order of images
- * in the WIM.
- */
+ const struct wim_security_data *sd;
const unsigned random_tail_len = 20;
DEBUG("Writing metadata resource for image %d", w->current_image);
root = wim_root_dentry(w);
+ sd = wim_security_data(w);
- const struct wim_security_data *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(sd);
- subdir_offset = sd->total_length + root->length + 8;
+
+ /* 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_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 + random_tail_len;
+
+ /* Allocate a buffer to contain the uncompressed metadata resource */
buf = MALLOC(metadata_original_size);
if (!buf) {
ERROR("Failed to allocate %"PRIu64" bytes for "
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 */
DEBUG("Writing dentry tree.");
p = write_dentry_tree(root, p);
+
+ /*
+ * Append 20 random bytes to the metadata resource so that we don't have
+ * identical metadata resources if we happen to append exactly the same
+ * image twice without any changes in timestamps. If this were to
+ * happen, it would cause confusion about the number and order of images
+ * in the WIM.
+ */
randomize_byte_array(p, random_tail_len);
+
+ /* We MUST have exactly filled the buffer; otherwise we calculated its
+ * size incorrectly or wrote the data incorrectly. */
wimlib_assert(p - buf + random_tail_len == metadata_original_size);
+ /* Get the lookup table entry for the metadata resource so we can update
+ * it. */
lte = wim_metadata_lookup_table_entry(w);
+ /* 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, so
+ * re-insert the lookup table entry into the lookup table. */
lookup_table_unlink(w->lookup_table, lte);
lookup_table_insert(w->lookup_table, lte);
+
+ /* We do not allow a metadata resource to be referenced multiple times,
+ * and the 20 random bytes appended to it should make it extremely
+ * likely for each metadata resource to be unique, even if the exact
+ * same image is captured. */
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;
}
git://wimlib.net / wimlib / blobdiff