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package vfs
import (
"fmt"
"os"
"path/filepath"
"strings"
"github.com/containers/storage/drivers"
"github.com/containers/storage/pkg/chrootarchive"
"github.com/containers/storage/pkg/idtools"
"github.com/containers/storage/pkg/ostree"
"github.com/containers/storage/pkg/system"
"github.com/opencontainers/selinux/go-selinux/label"
)
var (
// CopyWithTar defines the copy method to use.
CopyWithTar = chrootarchive.NewArchiver(nil).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{
homes: []string{home},
idMappings: idtools.NewIDMappingsFromMaps(uidMaps, gidMaps),
}
rootIDs := d.idMappings.RootPair()
if err := idtools.MkdirAllAndChown(home, 0700, rootIDs); err != nil {
return nil, err
}
for _, option := range options {
if strings.HasPrefix(option, "vfs.imagestore=") {
d.homes = append(d.homes, strings.Split(option[15:], ",")...)
continue
}
if strings.HasPrefix(option, ".imagestore=") {
d.homes = append(d.homes, strings.Split(option[12:], ",")...)
continue
}
if strings.HasPrefix(option, "vfs.ostree_repo=") {
if !ostree.OstreeSupport() {
return nil, fmt.Errorf("vfs: ostree_repo specified but support for ostree is missing")
}
d.ostreeRepo = option[16:]
}
if strings.HasPrefix(option, ".ostree_repo=") {
if !ostree.OstreeSupport() {
return nil, fmt.Errorf("vfs: ostree_repo specified but support for ostree is missing")
}
d.ostreeRepo = option[13:]
}
if strings.HasPrefix(option, "vfs.mountopt=") {
return nil, fmt.Errorf("vfs driver does not support mount options")
}
}
if d.ostreeRepo != "" {
rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
if err != nil {
return nil, err
}
if err := ostree.CreateOSTreeRepository(d.ostreeRepo, rootUID, rootGID); err != nil {
return nil, err
}
}
return graphdriver.NewNaiveDiffDriver(d, graphdriver.NewNaiveLayerIDMapUpdater(d)), 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 {
homes []string
idMappings *idtools.IDMappings
ostreeRepo string
}
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
}
// Metadata is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any meta data.
func (d *Driver) Metadata(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, false)
}
// 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 {
return d.create(id, parent, opts, true)
}
func (d *Driver) create(id, parent string, opts *graphdriver.CreateOpts, ro bool) error {
if opts != nil && len(opts.StorageOpt) != 0 {
return fmt.Errorf("--storage-opt is not supported for vfs")
}
dir := d.dir(id)
rootIDs := d.idMappings.RootPair()
if err := idtools.MkdirAllAndChown(filepath.Dir(dir), 0700, rootIDs); err != nil {
return err
}
if parent != "" {
st, err := system.Stat(d.dir(parent))
if err != nil {
return err
}
rootIDs.UID = int(st.UID())
rootIDs.GID = int(st.GID())
}
if err := idtools.MkdirAndChown(dir, 0755, rootIDs); err != nil {
return err
}
labelOpts := []string{"level:s0"}
if _, mountLabel, err := label.InitLabels(labelOpts); err == nil {
label.SetFileLabel(dir, mountLabel)
}
if parent != "" {
parentDir, err := d.Get(parent, graphdriver.MountOpts{})
if err != nil {
return fmt.Errorf("%s: %s", parent, err)
}
if err := CopyWithTar(parentDir, dir); err != nil {
return err
}
}
if ro && d.ostreeRepo != "" {
if err := ostree.ConvertToOSTree(d.ostreeRepo, dir, id); err != nil {
return err
}
}
return nil
}
func (d *Driver) dir(id string) string {
for i, home := range d.homes {
if i > 0 {
home = filepath.Join(home, d.String())
}
candidate := filepath.Join(home, "dir", filepath.Base(id))
fi, err := os.Stat(candidate)
if err == nil && fi.IsDir() {
return candidate
}
}
return filepath.Join(d.homes[0], "dir", filepath.Base(id))
}
// Remove deletes the content from the directory for a given id.
func (d *Driver) Remove(id string) error {
if d.ostreeRepo != "" {
// Ignore errors, we don't want to fail if the ostree branch doesn't exist,
ostree.DeleteOSTree(d.ostreeRepo, id)
}
return system.EnsureRemoveAll(d.dir(id))
}
// Get returns the directory for the given id.
func (d *Driver) Get(id string, options graphdriver.MountOpts) (_ string, retErr error) {
dir := d.dir(id)
if len(options.Options) > 0 {
return "", fmt.Errorf("vfs driver does not support mount options")
}
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
}
// AdditionalImageStores returns additional image stores supported by the driver
func (d *Driver) AdditionalImageStores() []string {
if len(d.homes) > 1 {
return d.homes[1:]
}
return nil
}
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