@Input
  public MapProperty<String, String> getPermissions() {
    String property = System.getProperty(PropertyNames.EXTRA_DIRECTORIES_PERMISSIONS);
    if (property != null) {
      Map<String, String> parsedPermissions =
          ConfigurationPropertyValidator.parseMapProperty(property);
      if (!parsedPermissions.equals(permissions.get())) {
        permissions.set(parsedPermissions);
      }
    }
    return permissions;
  }
Gets the permissions for files in the extra layer on the container. Maps from absolute path on
the container to a 3-digit octal string representation of the file permission bits (e.g. {@code
"/path/on/container" -> "755"}).

@return the permissions map from path on container to file permissions
jib-gradle-plugin/src/main/java/com/google/cloud/tools/jib/gradle/ExtraDirectoriesParameters.java