def task__squashfs_backup():
    """
    Backup files from image/squashfs

    Backup files to be restored after updating image/squashfs

    :actions:
      - ``sudo cp image/preseed/ubuntu.seed build/backup/ubuntu.seed``
      - ``sudo cp squashfs-root/etc/apt/sources.list build/backup/sources.list``
      - ``sudo mv squashfs-root/etc/resolv.conf squashfs-root/etc/resolv.conf.orig``
    :targets:
      - build/backup/ubuntu.seed
      - build/backup/sources.list
      - squashfs-root/etc/resolv.conf.orig
    :task_dep:
      - :func:`task__mount_dev`
    :uptodate:
      - True
    """
    return {'actions': [
        'sudo cp image/preseed/ubuntu.seed build/backup/ubuntu.seed || true',
        'sudo cp squashfs-root/etc/apt/sources.list build/backup/sources.list',
        'sudo mv squashfs-root/etc/resolv.conf squashfs-root/etc/resolv.conf.orig'
        ], 'targets': ['build/backup/sources.list',
        'squashfs-root/etc/resolv.conf.orig'], 'task_dep': ['_mount_dev'],
        'uptodate': [True]}
