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volumes.go
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volumes.go
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package daemon
import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"github.com/docker/docker/daemon/execdriver"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/runconfig"
"github.com/docker/docker/volume"
)
type mountPoint struct {
Name string
Destination string
Driver string
RW bool
Volume volume.Volume `json:"-"`
Source string
}
func (m *mountPoint) Setup() (string, error) {
if m.Volume != nil {
return m.Volume.Mount()
}
if len(m.Source) > 0 {
if _, err := os.Stat(m.Source); err != nil {
if !os.IsNotExist(err) {
return "", err
}
if err := os.MkdirAll(m.Source, 0755); err != nil {
return "", err
}
}
return m.Source, nil
}
return "", fmt.Errorf("Unable to setup mount point, neither source nor volume defined")
}
func (m *mountPoint) Path() string {
if m.Volume != nil {
return m.Volume.Path()
}
return m.Source
}
func parseBindMount(spec string, config *runconfig.Config) (*mountPoint, error) {
bind := &mountPoint{
RW: true,
}
arr := strings.Split(spec, ":")
switch len(arr) {
case 2:
bind.Destination = arr[1]
case 3:
bind.Destination = arr[1]
if !validMountMode(arr[2]) {
return nil, fmt.Errorf("invalid mode for volumes-from: %s", arr[2])
}
bind.RW = arr[2] == "rw"
default:
return nil, fmt.Errorf("Invalid volume specification: %s", spec)
}
name, source, err := parseVolumeSource(arr[0], config)
if err != nil {
return nil, err
}
if len(source) == 0 {
bind.Driver = config.VolumeDriver
if len(bind.Driver) == 0 {
bind.Driver = volume.DefaultDriverName
}
} else {
bind.Source = filepath.Clean(source)
}
bind.Name = name
bind.Destination = filepath.Clean(bind.Destination)
return bind, nil
}
func parseVolumesFrom(spec string) (string, string, error) {
if len(spec) == 0 {
return "", "", fmt.Errorf("malformed volumes-from specification: %s", spec)
}
specParts := strings.SplitN(spec, ":", 2)
id := specParts[0]
mode := "rw"
if len(specParts) == 2 {
mode = specParts[1]
if !validMountMode(mode) {
return "", "", fmt.Errorf("invalid mode for volumes-from: %s", mode)
}
}
return id, mode, nil
}
func validMountMode(mode string) bool {
validModes := map[string]bool{
"rw": true,
"ro": true,
}
return validModes[mode]
}
func (container *Container) specialMounts() []execdriver.Mount {
var mounts []execdriver.Mount
if container.ResolvConfPath != "" {
mounts = append(mounts, execdriver.Mount{Source: container.ResolvConfPath, Destination: "/etc/resolv.conf", Writable: !container.hostConfig.ReadonlyRootfs, Private: true})
}
if container.HostnamePath != "" {
mounts = append(mounts, execdriver.Mount{Source: container.HostnamePath, Destination: "/etc/hostname", Writable: !container.hostConfig.ReadonlyRootfs, Private: true})
}
if container.HostsPath != "" {
mounts = append(mounts, execdriver.Mount{Source: container.HostsPath, Destination: "/etc/hosts", Writable: !container.hostConfig.ReadonlyRootfs, Private: true})
}
return mounts
}
func copyExistingContents(source, destination string) error {
volList, err := ioutil.ReadDir(source)
if err != nil {
return err
}
if len(volList) > 0 {
srcList, err := ioutil.ReadDir(destination)
if err != nil {
return err
}
if len(srcList) == 0 {
// If the source volume is empty copy files from the root into the volume
if err := chrootarchive.CopyWithTar(source, destination); err != nil {
return err
}
}
}
return copyOwnership(source, destination)
}
// registerMountPoints initializes the container mount points with the configured volumes and bind mounts.
// It follows the next sequence to decide what to mount in each final destination:
//
// 1. Select the previously configured mount points for the containers, if any.
// 2. Select the volumes mounted from another containers. Overrides previously configured mount point destination.
// 3. Select the bind mounts set by the client. Overrides previously configured mount point destinations.
func (daemon *Daemon) registerMountPoints(container *Container, hostConfig *runconfig.HostConfig) error {
binds := map[string]bool{}
mountPoints := map[string]*mountPoint{}
// 1. Read already configured mount points.
for name, point := range container.MountPoints {
mountPoints[name] = point
}
// 2. Read volumes from other containers.
for _, v := range hostConfig.VolumesFrom {
containerID, mode, err := parseVolumesFrom(v)
if err != nil {
return err
}
c, err := daemon.Get(containerID)
if err != nil {
return err
}
for _, m := range c.MountPoints {
cp := m
cp.RW = m.RW && mode != "ro"
if len(m.Source) == 0 {
v, err := createVolume(m.Name, m.Driver)
if err != nil {
return err
}
cp.Volume = v
}
mountPoints[cp.Destination] = cp
}
}
// 3. Read bind mounts
for _, b := range hostConfig.Binds {
// #10618
bind, err := parseBindMount(b, container.Config)
if err != nil {
return err
}
if binds[bind.Destination] {
return fmt.Errorf("Duplicate bind mount %s", bind.Destination)
}
if len(bind.Name) > 0 && len(bind.Driver) > 0 {
v, err := createVolume(bind.Name, bind.Driver)
if err != nil {
return err
}
bind.Volume = v
}
binds[bind.Destination] = true
mountPoints[bind.Destination] = bind
}
container.MountPoints = mountPoints
return nil
}
// verifyOldVolumesInfo ports volumes configured for the containers pre docker 1.7.
// It reads the container configuration and creates valid mount points for the old volumes.
func (daemon *Daemon) verifyOldVolumesInfo(container *Container) error {
jsonPath, err := container.jsonPath()
if err != nil {
return err
}
f, err := os.Open(jsonPath)
if err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
type oldContVolCfg struct {
Volumes map[string]string
VolumesRW map[string]bool
}
vols := oldContVolCfg{
Volumes: make(map[string]string),
VolumesRW: make(map[string]bool),
}
if err := json.NewDecoder(f).Decode(&vols); err != nil {
return err
}
for destination, hostPath := range vols.Volumes {
vfsPath := filepath.Join(daemon.root, "vfs", "dir")
if strings.HasPrefix(hostPath, vfsPath) {
id := filepath.Base(hostPath)
rw := vols.VolumesRW != nil && vols.VolumesRW[destination]
container.addLocalMountPoint(id, destination, rw)
}
}
return container.ToDisk()
}
func createVolume(name, driverName string) (volume.Volume, error) {
vd, err := getVolumeDriver(driverName)
if err != nil {
return nil, err
}
return vd.Create(name)
}
func removeVolume(v volume.Volume) error {
vd, err := getVolumeDriver(v.DriverName())
if err != nil {
return nil
}
return vd.Remove(v)
}