+ u16 num_ads;
+ struct wim_ads_entry *ads_entries;
+ int ret;
+
+ BUILD_BUG_ON(sizeof(struct wim_ads_entry_on_disk) != WIM_ADS_ENTRY_DISK_SIZE);
+
+ /* Allocate an array for our in-memory representation of the alternate
+ * data stream entries. */
+ num_ads = inode->i_num_ads;
+ ads_entries = CALLOC(num_ads, sizeof(inode->i_ads_entries[0]));
+ if (!ads_entries)
+ goto out_of_memory;
+
+ /* Read the entries into our newly allocated buffer. */
+ for (u16 i = 0; i < num_ads; i++) {
+ u64 length;
+ struct wim_ads_entry *cur_entry;
+ const struct wim_ads_entry_on_disk *disk_entry =
+ (const struct wim_ads_entry_on_disk*)p;
+
+ cur_entry = &ads_entries[i];
+ ads_entries[i].stream_id = i + 1;
+
+ /* Do we have at least the size of the fixed-length data we know
+ * need? */
+ if (nbytes_remaining < sizeof(struct wim_ads_entry_on_disk))
+ goto out_invalid;
+
+ /* Read the length field */
+ length = le64_to_cpu(disk_entry->length);
+
+ /* Make sure the length field is neither so small it doesn't
+ * include all the fixed-length data nor so large it overflows
+ * the metadata resource buffer. */
+ if (length < sizeof(struct wim_ads_entry_on_disk) ||
+ length > nbytes_remaining)
+ goto out_invalid;
+
+ /* Read the rest of the fixed-length data. */
+
+ cur_entry->reserved = le64_to_cpu(disk_entry->reserved);
+ copy_hash(cur_entry->hash, disk_entry->hash);
+ cur_entry->stream_name_nbytes = le16_to_cpu(disk_entry->stream_name_nbytes);
+
+ /* If stream_name_nbytes != 0, this is a named stream.
+ * Otherwise this is an unnamed stream, or in some cases (bugs
+ * in Microsoft's software I guess) a meaningless entry
+ * distinguished from the real unnamed stream entry, if any, by
+ * the fact that the real unnamed stream entry has a nonzero
+ * hash field. */
+ if (cur_entry->stream_name_nbytes) {
+ /* The name is encoded in UTF16-LE, which uses 2-byte
+ * coding units, so the length of the name had better be
+ * an even number of bytes... */
+ if (cur_entry->stream_name_nbytes & 1)
+ goto out_invalid;
+
+ /* Add the length of the stream name to get the length
+ * we actually need to read. Make sure this isn't more
+ * than the specified length of the entry. */
+ if (sizeof(struct wim_ads_entry_on_disk) +
+ cur_entry->stream_name_nbytes > length)
+ goto out_invalid;
+
+ cur_entry->stream_name = MALLOC(cur_entry->stream_name_nbytes + 2);
+ if (!cur_entry->stream_name)
+ goto out_of_memory;
+
+ memcpy(cur_entry->stream_name,
+ disk_entry->stream_name,
+ cur_entry->stream_name_nbytes);
+ cur_entry->stream_name[cur_entry->stream_name_nbytes / 2] = cpu_to_le16(0);
+ }
+
+ /* It's expected that the size of every ADS entry is a multiple
+ * of 8. However, to be safe, I'm allowing the possibility of
+ * an ADS entry at the very end of the metadata resource ending
+ * un-aligned. So although we still need to increment the input
+ * pointer by @length to reach the next ADS entry, it's possible
+ * that less than @length is actually remaining in the metadata
+ * resource. We should set the remaining bytes to 0 if this
+ * happens. */
+ length = (length + 7) & ~(u64)7;
+ p += length;
+ if (nbytes_remaining < length)
+ nbytes_remaining = 0;
+ else
+ nbytes_remaining -= length;
+ }
+ inode->i_ads_entries = ads_entries;
+ inode->i_next_stream_id = inode->i_num_ads + 1;
+ ret = 0;
+ goto out;
+out_of_memory:
+ ret = WIMLIB_ERR_NOMEM;
+ goto out_free_ads_entries;
+out_invalid:
+ ERROR("An alternate data stream entry is invalid");
+ ret = WIMLIB_ERR_INVALID_DENTRY;
+out_free_ads_entries:
+ if (ads_entries) {
+ for (u16 i = 0; i < num_ads; i++)
+ destroy_ads_entry(&ads_entries[i]);
+ FREE(ads_entries);
+ }
+out:
+ return ret;
+}
+
+/*
+ * Reads a WIM directory entry, including all alternate data stream entries that
+ * follow it, from the WIM image's metadata resource.
+ *
+ * @metadata_resource:
+ * Pointer to the metadata resource buffer.
+ *
+ * @metadata_resource_len:
+ * Length of the metadata resource buffer, in bytes.
+ *
+ * @offset: Offset of the dentry within the metadata resource.
+ *
+ * @dentry: A `struct wim_dentry' that will be filled in by this function.
+ *
+ * Return 0 on success or nonzero on failure. On failure, @dentry will have
+ * been modified, but it will not be left with pointers to any allocated
+ * buffers. On success, the dentry->length field must be examined. If zero,
+ * this was a special "end of directory" dentry and not a real dentry. If
+ * nonzero, this was a real dentry.
+ *
+ * Possible errors include:
+ * WIMLIB_ERR_NOMEM
+ * WIMLIB_ERR_INVALID_DENTRY
+ */
+int
+read_dentry(const u8 * restrict metadata_resource, u64 metadata_resource_len,
+ u64 offset, struct wim_dentry * restrict dentry)
+{
+