// Init returns a new AUFS driver.
// An error is returned if AUFS is not supported.
func Init(root string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
// Try to load the aufs kernel module
if err := supportsAufs(); err != nil {
return nil, graphdriver.ErrNotSupported
}
fsMagic, err := graphdriver.GetFSMagic(root)
if err != nil {
return nil, err
}
if fsName, ok := graphdriver.FsNames[fsMagic]; ok {
backingFs = fsName
}
for _, magic := range incompatibleFsMagic {
if fsMagic == magic {
return nil, graphdriver.ErrIncompatibleFS
}
}
paths := []string{
"mnt",
"diff",
"layers",
}
a := &Driver{
root: root,
active: make(map[string]*data),
uidMaps: uidMaps,
gidMaps: gidMaps,
}
rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
if err != nil {
return nil, err
}
// Create the root aufs driver dir and return
// if it already exists
// If not populate the dir structure
if err := idtools.MkdirAllAs(root, 0755, rootUID, rootGID); err != nil {
if os.IsExist(err) {
return a, nil
}
return nil, err
}
if err := mountpk.MakePrivate(root); err != nil {
return nil, err
}
// Populate the dir structure
for _, p := range paths {
if err := idtools.MkdirAllAs(path.Join(root, p), 0755, rootUID, rootGID); err != nil {
return nil, err
}
}
return a, nil
}
// NewGraph instantiates a new graph at the given root path in the filesystem.
// `root` will be created if it doesn't exist.
func NewGraph(root string, driver graphdriver.Driver, uidMaps, gidMaps []idtools.IDMap) (*Graph, error) {
abspath, err := filepath.Abs(root)
if err != nil {
return nil, err
}
rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
if err != nil {
return nil, err
}
// Create the root directory if it doesn't exists
if err := idtools.MkdirAllAs(root, 0700, rootUID, rootGID); err != nil && !os.IsExist(err) {
return nil, err
}
graph := &Graph{
root: abspath,
idIndex: truncindex.NewTruncIndex([]string{}),
driver: driver,
retained: &retainedLayers{layerHolders: make(map[string]map[string]struct{})},
uidMaps: uidMaps,
gidMaps: gidMaps,
parentRefs: make(map[string]int),
}
// Windows does not currently support tarsplit functionality.
if runtime.GOOS == "windows" {
graph.tarSplitDisabled = true
}
if err := graph.restore(); err != nil {
return nil, err
}
return graph, nil
}
// mktemp creates a temporary sub-directory inside the graph's filesystem.
func (graph *Graph) mktemp() (string, error) {
dir := filepath.Join(graph.root, "_tmp", stringid.GenerateNonCryptoID())
rootUID, rootGID, err := idtools.GetRootUIDGID(graph.uidMaps, graph.gidMaps)
if err != nil {
return "", err
}
if err := idtools.MkdirAllAs(dir, 0700, rootUID, rootGID); err != nil {
return "", err
}
return dir, nil
}
func (a *Driver) createDirsFor(id string) error {
paths := []string{
"mnt",
"diff",
}
rootUID, rootGID, err := idtools.GetRootUIDGID(a.uidMaps, a.gidMaps)
if err != nil {
return err
}
for _, p := range paths {
if err := idtools.MkdirAllAs(path.Join(a.rootPath(), p, id), 0755, rootUID, rootGID); err != nil {
return err
}
}
return nil
}