]> wimlib.net Git - wimlib/blobdiff - src/metadata_resource.c
read_wim_lookup_table(): Ignore metadata entries with refcnt == 0
[wimlib] / src / metadata_resource.c
index 13ebf51ff6611dc2ddcc854153d3487abae944de..e632198940f332928b2e543b78e55e7fd8aa6d77 100644 (file)
  * 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.
  *
- * @w:         Pointer to the WIMStruct for the WIM file.
+ * @wim:
+ *     Pointer to the WIMStruct for the WIM file.
  *
- * @imd:       Pointer to the image metadata structure for the image whose
- *             metadata resource we are reading.  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.
+ * @imd:
+ *     Pointer to the image metadata structure for the image whose metadata
+ *     resource we are reading.  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.
  *
- * Returns:    Zero on success, nonzero on failure.
+ * Return values:
+ *     WIMLIB_ERR_SUCCESS (0)
+ *     WIMLIB_ERR_INVALID_METADATA_RESOURCE
+ *     WIMLIB_ERR_NOMEM
+ *     WIMLIB_ERR_READ
+ *     WIMLIB_ERR_UNEXPECTED_END_OF_FILE
+ *     WIMLIB_ERR_DECOMPRESSION
  */
 int
 read_metadata_resource(WIMStruct *wim, struct wim_image_metadata *imd)
 {
-       u8 *buf;
+       void *buf;
        int ret;
        struct wim_dentry *root;
        const struct wim_lookup_table_entry *metadata_lte;
        u64 metadata_len;
+       u8 hash[SHA1_HASH_SIZE];
+       struct wim_security_data *security_data;
+       struct wim_inode *inode;
 
        metadata_lte = imd->metadata_lte;
        metadata_len = wim_resource_size(metadata_lte);
@@ -76,44 +86,27 @@ read_metadata_resource(WIMStruct *wim, struct wim_image_metadata *imd)
        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;
+               return WIMLIB_ERR_INVALID_METADATA_RESOURCE;
        }
 
        /* Read the metadata resource into memory.  (It may be compressed.) */
-       ret = read_full_resource_into_buf(metadata_lte, buf);
+       ret = read_full_resource_into_alloc_buf(metadata_lte, &buf);
        if (ret)
-               goto out_free_buf;
+               return ret;
+
+       if (!metadata_lte->dont_check_metadata_hash) {
+               sha1_buffer(buf, metadata_len, hash);
+               if (!hashes_equal(metadata_lte->hash, hash)) {
+                       ERROR("Metadata resource is corrupted "
+                             "(invalid SHA-1 message digest)!");
+                       ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
+                       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,
-        * which takes case of rouding total_length.  If successful, go ahead
-        * and calculate the offset in the metadata resource of the root dentry.
-        * */
-
-       ret = read_wim_security_data(buf, metadata_len, &imd->security_data);
+       ret = read_wim_security_data(buf, metadata_len, &security_data);
        if (ret)
                goto out_free_buf;
 
@@ -126,12 +119,20 @@ read_metadata_resource(WIMStruct *wim, struct wim_image_metadata *imd)
                goto out_free_security_data;
        }
 
+       /* The root directory entry starts after security data, aligned on an
+        * 8-byte boundary within the metadata resource.  Since
+        * security_data->total_length was already rounded up to an 8-byte
+        * boundary, its value can be used as the offset of the root directory
+        * entry.  */
        ret = read_dentry(buf, metadata_len,
-                         imd->security_data->total_length, root);
+                         security_data->total_length, root);
 
        if (ret == 0 && root->length == 0) {
-               ERROR("Metadata resource cannot begin with end-of-directory entry!");
-               ret = WIMLIB_ERR_INVALID_DENTRY;
+               WARNING("Metadata resource begins with end-of-directory entry "
+                       "(treating as empty image)");
+               FREE(root);
+               root = NULL;
+               goto out_success;
        }
 
        if (ret) {
@@ -139,6 +140,23 @@ read_metadata_resource(WIMStruct *wim, struct wim_image_metadata *imd)
                goto out_free_security_data;
        }
 
+       if (dentry_has_long_name(root) || dentry_has_short_name(root)) {
+               WARNING("The root directory has a nonempty name (removing it)");
+               FREE(root->file_name);
+               FREE(root->short_name);
+               root->file_name = NULL;
+               root->short_name = NULL;
+               root->file_name_nbytes = 0;
+               root->short_name_nbytes = 0;
+       }
+
+       if (!dentry_is_directory(root)) {
+               ERROR("Root of the WIM image must be a directory!");
+               FREE(root);
+               ret = WIMLIB_ERR_INVALID_METADATA_RESOURCE;
+               goto out_free_security_data;
+       }
+
        /* This is the root dentry, so set its parent to itself. */
        root->parent = root;
 
@@ -155,26 +173,24 @@ read_metadata_resource(WIMStruct *wim, struct wim_image_metadata *imd)
        if (ret)
                goto out_free_dentry_tree;
 
-       if (!wim->all_images_verified) {
-               /* Note: verify_dentry() expects to access imd->security_data,
-                * so it needs to be set before here. */
-               DEBUG("Running miscellaneous verifications on the dentry tree");
-               for_lookup_table_entry(wim->lookup_table, lte_zero_real_refcnt, NULL);
-               ret = for_dentry_in_tree(root, verify_dentry, wim);
+
+       DEBUG("Running miscellaneous verifications on the dentry tree");
+       image_for_each_inode(inode, imd) {
+               ret = verify_inode(inode, security_data);
                if (ret)
                        goto out_free_dentry_tree;
        }
-
        DEBUG("Done reading image metadata");
-
+out_success:
        imd->root_dentry = root;
+       imd->security_data = security_data;
        INIT_LIST_HEAD(&imd->unhashed_streams);
+       ret = 0;
        goto out_free_buf;
 out_free_dentry_tree:
        free_dentry_tree(root, wim->lookup_table);
 out_free_security_data:
-       free_wim_security_data(imd->security_data);
-       imd->security_data = NULL;
+       free_wim_security_data(security_data);
 out_free_buf:
        FREE(buf);
        return ret;
@@ -189,57 +205,32 @@ recalculate_security_data_length(struct wim_security_data *sd)
        sd->total_length = (total_length + 7) & ~7;
 }
 
-/* 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 void *buf, size_t buf_size,
-                              int out_fd, 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 wim_lookup_table_entry lte;
-       int ret;
-       lte.resource_location            = RESOURCE_IN_ATTACHED_BUFFER;
-       lte.attached_buffer              = (void*)buf;
-       lte.resource_entry.original_size = buf_size;
-       lte.resource_entry.flags         = 0;
-       lte.unhashed                     = 1;
-       ret = write_wim_resource(&lte, out_fd, out_ctype, out_res_entry, 0);
-       if (ret == 0)
-               copy_hash(hash, lte.hash);
-       return ret;
-}
-
-/* Write the metadata resource for the current WIM image. */
-int
-write_metadata_resource(WIMStruct *w)
+prepare_metadata_resource(WIMStruct *wim, int image,
+                         u8 **buf_ret, size_t *len_ret)
 {
        u8 *buf;
        u8 *p;
        int ret;
        u64 subdir_offset;
        struct wim_dentry *root;
-       struct wim_lookup_table_entry *lte;
-       u64 metadata_original_size;
+       u64 len;
        struct wim_security_data *sd;
        struct wim_image_metadata *imd;
 
-       wimlib_assert(w->out_fd != -1);
-       wimlib_assert(w->current_image != WIMLIB_NO_IMAGE);
+       DEBUG("Preparing metadata resource for image %d", image);
 
-       DEBUG("Writing metadata resource for image %d (offset = %"PRIu64")",
-             w->current_image, filedes_offset(w->out_fd));
+       ret = select_wim_image(wim, image);
+       if (ret)
+               return ret;
 
-       imd = w->image_metadata[w->current_image - 1];
+       imd = wim->image_metadata[image - 1];
 
        root = imd->root_dentry;
        sd = imd->security_data;
 
        if (!root) {
-               /* Empty image; create a dummy root. */
+               /* Empty image; create a dummy root.  */
                ret = new_filler_directory(T(""), &root);
                if (ret)
                        return ret;
@@ -257,49 +248,62 @@ write_metadata_resource(WIMStruct *w)
        subdir_offset = (((u64)sd->total_length + 7) & ~7) +
                        dentry_correct_total_length(root) + 8;
 
-       /* Calculate the subdirectory offsets for the entire dentry tree. */
+       /* 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;
+       /* Total length of the metadata resource (uncompressed) */
+       len = subdir_offset;
 
-       /* Allocate a buffer to contain the uncompressed metadata resource */
-       buf = MALLOC(metadata_original_size);
+       /* Allocate a buffer to contain the uncompressed metadata resource */
+       buf = MALLOC(len);
        if (!buf) {
                ERROR("Failed to allocate %"PRIu64" bytes for "
-                     "metadata resource", metadata_original_size);
+                     "metadata resource", len);
                return WIMLIB_ERR_NOMEM;
        }
 
-       /* Write the security data into the resource buffer */
+       /* Write the security data into the resource buffer */
        p = write_wim_security_data(sd, buf);
 
-       /* Write the dentry tree into the resource buffer */
+       /* 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);
+        * size incorrectly or wrote the data incorrectly.  */
+       wimlib_assert(p - buf == len);
+
+       *buf_ret = buf;
+       *len_ret = len;
+       return 0;
+}
+
+int
+write_metadata_resource(WIMStruct *wim, int image, int write_resource_flags)
+{
+       int ret;
+       u8 *buf;
+       size_t len;
+       struct wim_image_metadata *imd;
 
-       /* Get the lookup table entry for the metadata resource so we can update
-        * it. */
-       lte = wim_get_current_image_metadata(w)->metadata_lte;
+       ret = prepare_metadata_resource(wim, image, &buf, &len);
+       if (ret)
+               return ret;
+
+       imd = wim->image_metadata[image - 1];
 
        /* 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_fd,
-                                            wimlib_get_compression_type(w),
-                                            &lte->output_resource_entry,
-                                            lte->hash);
-       /* Note that although the SHA1 message digest of the metadata resource
-        * is very likely to have changed, the corresponding lookup table entry
-        * is not actually located in the hash table, so it need not be
-        * re-inserted in the hash table. */
-
-       /* All the data has been written to the new WIM; no need for the buffer
-        * anymore */
+        * compression type, in the process updating the lookup table entry for
+        * the metadata resource.  */
+       ret = write_wim_resource_from_buffer(buf, len, WIM_RESHDR_FLAG_METADATA,
+                                            &wim->out_fd,
+                                            wim->compression_type,
+                                            &imd->metadata_lte->output_resource_entry,
+                                            imd->metadata_lte->hash,
+                                            write_resource_flags);
+
+       /* Original checksum was overridden; set a flag so it isn't used.  */
+       imd->metadata_lte->dont_check_metadata_hash = 1;
+
        FREE(buf);
        return ret;
 }