GetConfig parses a subuid/subgid configuration file and returns a Config holding all mapping entries, it allows to pass a custom function getUserFn used to lookup in a custom user database, if there is no custom function, the default one is used.

GetGIDRange determines subUID mappings for the user uid based on the /etc/subgid file.

GetUIDRange determines subUID mappings for the user uid based on the /etc/subuid file.

SubGIDFile is the default path to the subgid file.

SubUIDFile is the default path to the subuid file.

Config holds all entries found in the corresponding configuration file and manages its configuration.

Entry represents an entry line of subuid/subgid configuration file.

GetUserFn defines the user lookup function prototype.