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moby--moby/daemon/graphdriver/vfs/driver.go
Srini Brahmaroutu 3e7f9c636a daemon/graphdriver/vfs fix lint errors/warnings
Addresses #14756
Signed-off-by: Srini Brahmaroutu <srbrahma@us.ibm.com>
2015-08-03 17:46:42 +00:00

116 lines
3.2 KiB
Go

// +build linux windows
package vfs
import (
"fmt"
"os"
"path/filepath"
"github.com/docker/docker/daemon/graphdriver"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/pkg/system"
"github.com/opencontainers/runc/libcontainer/label"
)
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) (graphdriver.Driver, error) {
d := &Driver{
home: home,
}
return graphdriver.NaiveDiffDriver(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 {
home 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
}
// 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
}
// 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) error {
dir := d.dir(id)
if err := system.MkdirAll(filepath.Dir(dir), 0700); err != nil {
return err
}
if err := os.Mkdir(dir, 0755); err != nil {
return err
}
opts := []string{"level:s0"}
if _, mountLabel, err := label.InitLabels(opts); 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 := chrootarchive.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.Stat(d.dir(id)); err != nil {
return err
}
return os.RemoveAll(d.dir(id))
}
// 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
}