+/*
+ * metadata_resource.c
+ */
+
+/*
+ * Copyright (C) 2012 Eric Biggers
+ *
+ * This file is part of wimlib, a library for working with WIM files.
+ *
+ * wimlib is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * wimlib is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * wimlib; if not, see http://www.gnu.org/licenses/.
+ */
+
+#include "wimlib_internal.h"
+#include "dentry.h"
+#include "lookup_table.h"
+
+/*
+ * Reads the metadata metadata resource from the WIM file. The metadata
+ * resource consists of the security data, followed by the directory entry for
+ * the root directory, followed by all the other directory entries in the
+ * filesystem. The subdir_offset field of each directory entry gives the start
+ * of its child entries from the beginning of the metadata resource. An
+ * end-of-directory is signaled by a directory entry of length '0', really of
+ * length 8, because that's how long the 'length' field is.
+ *
+ * @fp: The FILE* for the input WIM file.
+ * @wim_ctype: The compression type of the WIM file.
+ * @imd: Pointer to the image metadata structure. Its `metadata_lte'
+ * member specifies the lookup table entry for the metadata
+ * resource. The rest of the image metadata entry will be filled
+ * in by this function.
+ *
+ * @return: Zero on success, nonzero on failure.
+ */
+int read_metadata_resource(WIMStruct *w, struct image_metadata *imd)
+{
+ u8 *buf;
+ u32 dentry_offset;
+ int ret;
+ struct dentry *dentry;
+ struct inode_table inode_tab;
+ const struct lookup_table_entry *metadata_lte;
+ u64 metadata_len;
+ struct hlist_head inode_list;
+
+ metadata_lte = imd->metadata_lte;
+ metadata_len = wim_resource_size(metadata_lte);
+
+ DEBUG("Reading metadata resource: length = %"PRIu64", "
+ "offset = %"PRIu64"", metadata_len,
+ metadata_lte->resource_entry.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 %u bytes for the metadata resource",
+ 8 + WIM_DENTRY_DISK_SIZE);
+ return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
+ }
+
+ if (sizeof(size_t) < 8 && metadata_len > 0xffffffff) {
+ ERROR("Metadata resource is too large (%"PRIu64" bytes",
+ metadata_len);
+ return WIMLIB_ERR_INVALID_RESOURCE_SIZE;
+ }
+
+ /* Allocate memory for the uncompressed metadata resource. */
+ buf = MALLOC(metadata_len);
+
+ if (!buf) {
+ ERROR("Failed to allocate %"PRIu64" bytes for uncompressed "
+ "metadata resource", metadata_len);
+ return WIMLIB_ERR_NOMEM;
+ }
+
+ /* Read the metadata resource into memory. (It may be compressed.) */
+ ret = read_full_wim_resource(metadata_lte, buf, 0);
+ if (ret != 0)
+ goto out_free_buf;
+
+ DEBUG("Finished reading metadata resource into memory.");
+
+ /* 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, 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. */
+
+ wimlib_assert(imd->security_data == NULL);
+ ret = read_security_data(buf, metadata_len, &imd->security_data);
+ if (ret != 0)
+ goto out_free_buf;
+
+ dentry_offset = (imd->security_data->total_length + 7) & ~7;
+
+ if (dentry_offset == 0) {
+ ERROR("Integer overflow while reading metadata resource");
+ ret = WIMLIB_ERR_INVALID_SECURITY_DATA;
+ goto out_free_security_data;
+ }
+
+ DEBUG("Reading root dentry");
+
+ /* 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",
+ sizeof(struct dentry));
+ ret = WIMLIB_ERR_NOMEM;
+ goto out_free_security_data;
+ }
+
+ ret = read_dentry(buf, metadata_len, dentry_offset, dentry);
+
+ /* This is the root dentry, so set its parent to itself. */
+ dentry->parent = dentry;
+
+ if (ret == 0 && dentry->length == 0) {
+ ERROR("Metadata resource cannot begin with end-of-directory entry!");
+ ret = WIMLIB_ERR_INVALID_DENTRY;
+ }
+
+ if (ret != 0) {
+ FREE(dentry);
+ goto out_free_security_data;
+ }
+
+ inode_add_dentry(dentry, dentry->d_inode);
+
+ /* Now read the entire directory entry tree into memory. */
+ DEBUG("Reading dentry tree");
+ ret = read_dentry_tree(buf, metadata_len, dentry);
+ if (ret != 0)
+ goto out_free_dentry_tree;
+
+ /* 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;
+
+ /* Build hash table that maps hard link group IDs to dentry sets */
+ DEBUG("Building link group table");
+ ret = init_inode_table(&inode_tab, 9001);
+ if (ret != 0)
+ goto out_free_dentry_tree;
+
+ for_dentry_in_tree(dentry, inode_table_insert, &inode_tab);
+
+ DEBUG("Fixing inconsistencies in the hard link groups");
+ ret = fix_inodes(&inode_tab, &inode_list);
+ destroy_inode_table(&inode_tab);
+ if (ret != 0)
+ goto out_free_dentry_tree;
+
+ if (!w->all_images_verified) {
+ DEBUG("Running miscellaneous verifications on the dentry tree");
+ for_lookup_table_entry(w->lookup_table, lte_zero_real_refcnt, NULL);
+ ret = for_dentry_in_tree(dentry, verify_dentry, w);
+ if (ret != 0)
+ goto out_free_dentry_tree;
+ }
+
+ DEBUG("Done reading image metadata");
+
+ imd->root_dentry = dentry;
+ imd->inode_list = inode_list;
+ goto out_free_buf;
+out_free_dentry_tree:
+ free_dentry_tree(dentry, NULL);
+out_free_security_data:
+ free_security_data(imd->security_data);
+ imd->security_data = NULL;
+out_free_buf:
+ FREE(buf);
+ return ret;
+}
+
+static void recalculate_security_data_length(struct wim_security_data *sd)
+{
+ u32 total_length = sizeof(u64) * sd->num_entries + 2 * sizeof(u32);
+ for (u32 i = 0; i < sd->num_entries; i++)
+ total_length += sd->sizes[i];
+ sd->total_length = total_length;
+}
+
+/* Like write_wim_resource(), but the resource is specified by a buffer of
+ * uncompressed data rather a lookup table entry; also writes the SHA1 hash of
+ * the buffer to @hash. */
+static int write_wim_resource_from_buffer(const u8 *buf, u64 buf_size,
+ FILE *out_fp, int out_ctype,
+ struct resource_entry *out_res_entry,
+ u8 hash[SHA1_HASH_SIZE])
+{
+ /* Set up a temporary lookup table entry to provide to
+ * write_wim_resource(). */
+ struct lookup_table_entry lte;
+ int ret;
+ lte.resource_entry.flags = 0;
+ lte.resource_entry.original_size = buf_size;
+ lte.resource_entry.size = buf_size;
+ lte.resource_entry.offset = 0;
+ lte.resource_location = RESOURCE_IN_ATTACHED_BUFFER;
+ lte.attached_buffer = (u8*)buf;
+
+ zero_out_hash(lte.hash);
+ ret = write_wim_resource(<e, out_fp, out_ctype, out_res_entry, 0);
+ if (ret != 0)
+ return ret;
+ copy_hash(hash, lte.hash);
+ return 0;
+}
+
+/* Write the metadata resource for the current WIM image. */
+int write_metadata_resource(WIMStruct *w)
+{
+ u8 *buf;
+ u8 *p;
+ int ret;
+ u64 subdir_offset;
+ struct dentry *root;
+ struct lookup_table_entry *lte;
+ u64 metadata_original_size;
+ struct wim_security_data *sd;
+
+ DEBUG("Writing metadata resource for image %d (offset = %"PRIu64")",
+ w->current_image, ftello(w->out_fp));
+
+ root = wim_root_dentry(w);
+ sd = wim_security_data(w);
+
+ /* 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...)
+ */
+ recalculate_security_data_length(sd);
+ subdir_offset = (((u64)sd->total_length + 7) & ~7) +
+ dentry_correct_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;
+
+ /* Allocate a buffer to contain the uncompressed metadata resource */
+ buf = MALLOC(metadata_original_size);
+ if (!buf) {
+ ERROR("Failed to allocate %"PRIu64" bytes for "
+ "metadata resource", metadata_original_size);
+ 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 */
+ p = write_dentry_tree(root, p);
+
+ /* We MUST have exactly filled the buffer; otherwise we calculated its
+ * size incorrectly or wrote the data incorrectly. */
+ wimlib_assert(p - buf == metadata_original_size);
+
+ /* Get the lookup table entry for the metadata resource so we can update
+ * it. */
+ lte = w->image_metadata[w->current_image - 1].metadata_lte;
+
+ /* 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
+ * changed, so re-insert the lookup table entry into the lookup table.
+ *
+ * We do not check for other lookup table entries having the same SHA1
+ * message digest. It's possible for 2 absolutely identical images to
+ * be added, therefore causing 2 identical metadata resources to be in
+ * the WIM. However, in this case, it's expected for 2 separate lookup
+ * table entries to be created, even though this doesn't make a whole
+ * lot of sense since they will share the same SHA1 message digest.
+ * */
+ lookup_table_unlink(w->lookup_table, lte);
+ lookup_table_insert(w->lookup_table, lte);
+ lte->out_refcnt = 1;
+
+ /* Make sure that the lookup table entry for this metadata resource is
+ * 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 / commitdiff