package repository import ( "crypto/rand" "crypto/sha256" "encoding/hex" "errors" "io" "github.com/restic/chunker" "github.com/restic/restic/backend" "github.com/restic/restic/debug" ) // Config contains the configuration for a repository. type Config struct { Version uint `json:"version"` ID string `json:"id"` ChunkerPolynomial chunker.Pol `json:"chunker_polynomial"` } // repositoryIDSize is the length of the ID chosen at random for a new repository. const repositoryIDSize = sha256.Size // RepoVersion is the version that is written to the config when a repository // is newly created with Init(). const RepoVersion = 1 // JSONUnpackedSaver saves unpacked JSON. type JSONUnpackedSaver interface { SaveJSONUnpacked(backend.Type, interface{}) (backend.ID, error) } // JSONUnpackedLoader loads unpacked JSON. type JSONUnpackedLoader interface { LoadJSONUnpacked(backend.Type, backend.ID, interface{}) error } // CreateConfig creates a config file with a randomly selected polynomial and // ID and saves the config in the repository. func CreateConfig(r JSONUnpackedSaver) (Config, error) { var ( err error cfg Config ) cfg.ChunkerPolynomial, err = chunker.RandomPolynomial() if err != nil { return Config{}, err } newID := make([]byte, repositoryIDSize) _, err = io.ReadFull(rand.Reader, newID) if err != nil { return Config{}, err } cfg.ID = hex.EncodeToString(newID) cfg.Version = RepoVersion debug.Log("Repo.CreateConfig", "New config: %#v", cfg) _, err = r.SaveJSONUnpacked(backend.Config, cfg) return cfg, err } // LoadConfig returns loads, checks and returns the config for a repository. func LoadConfig(r JSONUnpackedLoader) (Config, error) { var ( cfg Config ) err := r.LoadJSONUnpacked(backend.Config, nil, &cfg) if err != nil { return Config{}, err } if cfg.Version != RepoVersion { return Config{}, errors.New("unsupported repository version") } if !cfg.ChunkerPolynomial.Irreducible() { return Config{}, errors.New("invalid chunker polynomial") } return cfg, nil }