| package vfs |
| |
| import ( |
| "fmt" |
| "os" |
| "path/filepath" |
| |
| "github.com/docker/docker/daemon/graphdriver" |
| "github.com/docker/docker/pkg/chrootarchive" |
| "github.com/docker/docker/pkg/idtools" |
| |
| "github.com/opencontainers/runc/libcontainer/label" |
| ) |
| |
| var ( |
| // CopyWithTar defines the copy method to use. |
| CopyWithTar = chrootarchive.CopyWithTar |
| ) |
| |
| func init() { |
| graphdriver.Register("vfs", Init) |
| } |
| |
| // Init returns a new VFS driver. |
| // This sets the home directory for the driver and returns NaiveDiffDriver. |
| func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) { |
| d := &Driver{ |
| home: home, |
| uidMaps: uidMaps, |
| gidMaps: gidMaps, |
| } |
| rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps) |
| if err != nil { |
| return nil, err |
| } |
| if err := idtools.MkdirAllAs(home, 0700, rootUID, rootGID); err != nil { |
| return nil, err |
| } |
| return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil |
| } |
| |
| // Driver holds information about the driver, home directory of the driver. |
| // Driver implements graphdriver.ProtoDriver. It uses only basic vfs operations. |
| // In order to support layering, files are copied from the parent layer into the new layer. There is no copy-on-write support. |
| // Driver must be wrapped in NaiveDiffDriver to be used as a graphdriver.Driver |
| type Driver struct { |
| home string |
| uidMaps []idtools.IDMap |
| gidMaps []idtools.IDMap |
| } |
| |
| func (d *Driver) String() string { |
| return "vfs" |
| } |
| |
| // Status is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any status information. |
| func (d *Driver) Status() [][2]string { |
| return nil |
| } |
| |
| // GetMetadata is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any meta data. |
| func (d *Driver) GetMetadata(id string) (map[string]string, error) { |
| return nil, nil |
| } |
| |
| // Cleanup is used to implement graphdriver.ProtoDriver. There is no cleanup required for this driver. |
| func (d *Driver) Cleanup() error { |
| return nil |
| } |
| |
| // CreateReadWrite creates a layer that is writable for use as a container |
| // file system. |
| func (d *Driver) CreateReadWrite(id, parent string, opts *graphdriver.CreateOpts) error { |
| return d.Create(id, parent, opts) |
| } |
| |
| // Create prepares the filesystem for the VFS driver and copies the directory for the given id under the parent. |
| func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error { |
| if opts != nil && len(opts.StorageOpt) != 0 { |
| return fmt.Errorf("--storage-opt is not supported for vfs") |
| } |
| |
| dir := d.dir(id) |
| rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps) |
| if err != nil { |
| return err |
| } |
| if err := idtools.MkdirAllAs(filepath.Dir(dir), 0700, rootUID, rootGID); err != nil { |
| return err |
| } |
| if err := idtools.MkdirAs(dir, 0755, rootUID, rootGID); err != nil { |
| return err |
| } |
| labelOpts := []string{"level:s0"} |
| if _, mountLabel, err := label.InitLabels(labelOpts); err == nil { |
| label.SetFileLabel(dir, mountLabel) |
| } |
| if parent == "" { |
| return nil |
| } |
| parentDir, err := d.Get(parent, "") |
| if err != nil { |
| return fmt.Errorf("%s: %s", parent, err) |
| } |
| if err := CopyWithTar(parentDir, dir); err != nil { |
| return err |
| } |
| return nil |
| } |
| |
| func (d *Driver) dir(id string) string { |
| return filepath.Join(d.home, "dir", filepath.Base(id)) |
| } |
| |
| // Remove deletes the content from the directory for a given id. |
| func (d *Driver) Remove(id string) error { |
| if err := os.RemoveAll(d.dir(id)); err != nil && !os.IsNotExist(err) { |
| return err |
| } |
| return nil |
| } |
| |
| // Get returns the directory for the given id. |
| func (d *Driver) Get(id, mountLabel string) (string, error) { |
| dir := d.dir(id) |
| if st, err := os.Stat(dir); err != nil { |
| return "", err |
| } else if !st.IsDir() { |
| return "", fmt.Errorf("%s: not a directory", dir) |
| } |
| return dir, nil |
| } |
| |
| // Put is a noop for vfs that return nil for the error, since this driver has no runtime resources to clean up. |
| func (d *Driver) Put(id string) error { |
| // The vfs driver has no runtime resources (e.g. mounts) |
| // to clean up, so we don't need anything here |
| return nil |
| } |
| |
| // Exists checks to see if the directory exists for the given id. |
| func (d *Driver) Exists(id string) bool { |
| _, err := os.Stat(d.dir(id)) |
| return err == nil |
| } |