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moby--moby/daemon/graphdriver/vfs/driver.go
Kato Kazuyoshi 733711481e cp's -T and --reflink=auto are only available on GNU coreutils
Docker-DCO-1.1-Signed-off-by: Kato Kazuyoshi <kato.kazuyoshi@gmail.com> (github: kzys)
2014-06-24 23:58:17 +09:00

112 lines
2.1 KiB
Go

package vfs
import (
"bytes"
"fmt"
"github.com/dotcloud/docker/daemon/graphdriver"
"os"
"os/exec"
"path"
)
func init() {
graphdriver.Register("vfs", Init)
}
func Init(home string, options []string) (graphdriver.Driver, error) {
d := &Driver{
home: home,
}
return d, nil
}
type Driver struct {
home string
}
func (d *Driver) String() string {
return "vfs"
}
func (d *Driver) Status() [][2]string {
return nil
}
func (d *Driver) Cleanup() error {
return nil
}
func isGNUcoreutils() bool {
if stdout, err := exec.Command("cp", "--version").Output(); err == nil {
return bytes.Contains(stdout, []byte("GNU coreutils"))
}
return false
}
func copyDir(src, dst string) error {
argv := make([]string, 0, 4)
if isGNUcoreutils() {
argv = append(argv, "-aT", "--reflink=auto", src, dst)
} else {
argv = append(argv, "-a", src+"/.", dst+"/.")
}
if output, err := exec.Command("cp", argv...).CombinedOutput(); err != nil {
return fmt.Errorf("Error VFS copying directory: %s (%s)", err, output)
}
return nil
}
func (d *Driver) Create(id, parent string) error {
dir := d.dir(id)
if err := os.MkdirAll(path.Dir(dir), 0700); err != nil {
return err
}
if err := os.Mkdir(dir, 0755); err != nil {
return err
}
if parent == "" {
return nil
}
parentDir, err := d.Get(parent, "")
if err != nil {
return fmt.Errorf("%s: %s", parent, err)
}
if err := copyDir(parentDir, dir); err != nil {
return err
}
return nil
}
func (d *Driver) dir(id string) string {
return path.Join(d.home, "dir", path.Base(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))
}
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
}
func (d *Driver) Put(id string) {
// The vfs driver has no runtime resources (e.g. mounts)
// to clean up, so we don't need anything here
}
func (d *Driver) Exists(id string) bool {
_, err := os.Stat(d.dir(id))
return err == nil
}