archive_read_set_callback_data2(struct archive *_a, void *client_data,
    unsigned int iindex)
{
	struct archive_read *a = (struct archive_read *)_a;
	archive_check_magic(_a, ARCHIVE_READ_MAGIC, ARCHIVE_STATE_NEW,
	    "archive_read_set_callback_data2");

	if (a->client.nodes == 0)
	{
		a->client.dataset = (struct archive_read_data_node *)
		    calloc(1, sizeof(*a->client.dataset));
		if (a->client.dataset == NULL)
		{
			archive_set_error(&a->archive, ENOMEM,
				"No memory.");
			return ARCHIVE_FATAL;
		}
		a->client.nodes = 1;
	}

	if (iindex > a->client.nodes - 1)
	{
		archive_set_error(&a->archive, EINVAL,
			"Invalid index specified.");
		return ARCHIVE_FATAL;
	}
	a->client.dataset[iindex].data = client_data;
	a->client.dataset[iindex].begin_position = -1;
	a->client.dataset[iindex].total_size = -1;
	return ARCHIVE_OK;
}

This vulnerability category highlights issues in resource management where failures to properly release memory, file handles, or other resources can degrade system performance or enable denial-of-service conditions.