elements = []
    # Add prefix.
    if prefix != '':
        elements.append(prefix)
        has_prefix = True
    else:
        has_prefix = False
    # Add osystem
    elements.append(osystem)
    # Add architecture/sub-architecture.
    if node is not None:
        arch = split_subarch(node.architecture)
        elements.extend(arch)
    # Add release.
    elements.append(release)
    # Add hostname.
    if node is not None:
        elements.append(node.hostname)
    while elements:
        yield compose_filename(elements)
        # Backward-compatibility fix for 1439366: also generate a filename
        # with the 'osystem' omitted when deploying with Ubuntu.
        if osystem == UBUNTU_NAME:
            should_emit = (
                (not has_prefix and len(elements) > 1) or
                (has_prefix and len(elements) > 2))
            if should_emit:
                cutoff = 1 if has_prefix else 0
                yield compose_filename(
                    elements[:cutoff] + elements[cutoff + 1:])
        elements.pop()
    if default:
        yield GENERIC_FILENAME