package daemon // import "github.com/docker/docker/daemon" import ( "context" "os" "path/filepath" "reflect" "strings" "time" "github.com/docker/docker/api/types" containertypes "github.com/docker/docker/api/types/container" "github.com/docker/docker/api/types/mount" mounttypes "github.com/docker/docker/api/types/mount" "github.com/docker/docker/container" "github.com/docker/docker/errdefs" "github.com/docker/docker/volume" volumemounts "github.com/docker/docker/volume/mounts" "github.com/docker/docker/volume/service" volumeopts "github.com/docker/docker/volume/service/opts" "github.com/pkg/errors" "github.com/sirupsen/logrus" ) var ( // ErrVolumeReadonly is used to signal an error when trying to copy data into // a volume mount that is not writable. ErrVolumeReadonly = errors.New("mounted volume is marked read-only") ) type mounts []container.Mount // Len returns the number of mounts. Used in sorting. func (m mounts) Len() int { return len(m) } // Less returns true if the number of parts (a/b/c would be 3 parts) in the // mount indexed by parameter 1 is less than that of the mount indexed by // parameter 2. Used in sorting. func (m mounts) Less(i, j int) bool { return m.parts(i) < m.parts(j) } // Swap swaps two items in an array of mounts. Used in sorting func (m mounts) Swap(i, j int) { m[i], m[j] = m[j], m[i] } // parts returns the number of parts in the destination of a mount. Used in sorting. func (m mounts) parts(i int) int { return strings.Count(filepath.Clean(m[i].Destination), string(os.PathSeparator)) } // 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. // 4. Cleanup old volumes that are about to be reassigned. func (daemon *Daemon) registerMountPoints(container *container.Container, hostConfig *containertypes.HostConfig) (retErr error) { binds := map[string]bool{} mountPoints := map[string]*volumemounts.MountPoint{} parser := volumemounts.NewParser(container.OS) ctx := context.TODO() defer func() { // clean up the container mountpoints once return with error if retErr != nil { for _, m := range mountPoints { if m.Volume == nil { continue } daemon.volumes.Release(ctx, m.Volume.Name(), container.ID) } } }() dereferenceIfExists := func(destination string) { if v, ok := mountPoints[destination]; ok { logrus.Debugf("Duplicate mount point '%s'", destination) if v.Volume != nil { daemon.volumes.Release(ctx, v.Volume.Name(), container.ID) } } } // 1. Read already configured mount points. for destination, point := range container.MountPoints { mountPoints[destination] = point } // 2. Read volumes from other containers. for _, v := range hostConfig.VolumesFrom { containerID, mode, err := parser.ParseVolumesFrom(v) if err != nil { return err } c, err := daemon.GetContainer(containerID) if err != nil { return err } for _, m := range c.MountPoints { cp := &volumemounts.MountPoint{ Type: m.Type, Name: m.Name, Source: m.Source, RW: m.RW && parser.ReadWrite(mode), Driver: m.Driver, Destination: m.Destination, Propagation: m.Propagation, Spec: m.Spec, CopyData: false, } if len(cp.Source) == 0 { v, err := daemon.volumes.Get(ctx, cp.Name, volumeopts.WithGetDriver(cp.Driver), volumeopts.WithGetReference(container.ID)) if err != nil { return err } cp.Volume = &volumeWrapper{v: v, s: daemon.volumes} } dereferenceIfExists(cp.Destination) mountPoints[cp.Destination] = cp } } // 3. Read bind mounts for _, b := range hostConfig.Binds { bind, err := parser.ParseMountRaw(b, hostConfig.VolumeDriver) if err != nil { return err } needsSlavePropagation, err := daemon.validateBindDaemonRoot(bind.Spec) if err != nil { return err } if needsSlavePropagation { bind.Propagation = mount.PropagationRSlave } // #10618 _, tmpfsExists := hostConfig.Tmpfs[bind.Destination] if binds[bind.Destination] || tmpfsExists { return duplicateMountPointError(bind.Destination) } if bind.Type == mounttypes.TypeVolume { // create the volume v, err := daemon.volumes.Create(ctx, bind.Name, bind.Driver, volumeopts.WithCreateReference(container.ID)) if err != nil { return err } bind.Volume = &volumeWrapper{v: v, s: daemon.volumes} bind.Source = v.Mountpoint // bind.Name is an already existing volume, we need to use that here bind.Driver = v.Driver if bind.Driver == volume.DefaultDriverName { setBindModeIfNull(bind) } } binds[bind.Destination] = true dereferenceIfExists(bind.Destination) mountPoints[bind.Destination] = bind } for _, cfg := range hostConfig.Mounts { mp, err := parser.ParseMountSpec(cfg) if err != nil { return errdefs.InvalidParameter(err) } needsSlavePropagation, err := daemon.validateBindDaemonRoot(mp.Spec) if err != nil { return err } if needsSlavePropagation { mp.Propagation = mount.PropagationRSlave } if binds[mp.Destination] { return duplicateMountPointError(cfg.Target) } if mp.Type == mounttypes.TypeVolume { var v *types.Volume if cfg.VolumeOptions != nil { var driverOpts map[string]string if cfg.VolumeOptions.DriverConfig != nil { driverOpts = cfg.VolumeOptions.DriverConfig.Options } v, err = daemon.volumes.Create(ctx, mp.Name, mp.Driver, volumeopts.WithCreateReference(container.ID), volumeopts.WithCreateOptions(driverOpts), volumeopts.WithCreateLabels(cfg.VolumeOptions.Labels), ) } else { v, err = daemon.volumes.Create(ctx, mp.Name, mp.Driver, volumeopts.WithCreateReference(container.ID)) } if err != nil { return err } mp.Volume = &volumeWrapper{v: v, s: daemon.volumes} mp.Name = v.Name mp.Driver = v.Driver // need to selinux-relabel local mounts mp.Source = v.Mountpoint if mp.Driver == volume.DefaultDriverName { setBindModeIfNull(mp) } } if mp.Type == mounttypes.TypeBind { mp.SkipMountpointCreation = true } binds[mp.Destination] = true dereferenceIfExists(mp.Destination) mountPoints[mp.Destination] = mp } container.Lock() // 4. Cleanup old volumes that are about to be reassigned. for _, m := range mountPoints { if parser.IsBackwardCompatible(m) { if mp, exists := container.MountPoints[m.Destination]; exists && mp.Volume != nil { daemon.volumes.Release(ctx, mp.Volume.Name(), container.ID) } } } container.MountPoints = mountPoints container.Unlock() return nil } // lazyInitializeVolume initializes a mountpoint's volume if needed. // This happens after a daemon restart. func (daemon *Daemon) lazyInitializeVolume(containerID string, m *volumemounts.MountPoint) error { if len(m.Driver) > 0 && m.Volume == nil { v, err := daemon.volumes.Get(context.TODO(), m.Name, volumeopts.WithGetDriver(m.Driver), volumeopts.WithGetReference(containerID)) if err != nil { return err } m.Volume = &volumeWrapper{v: v, s: daemon.volumes} } return nil } // backportMountSpec resolves mount specs (introduced in 1.13) from pre-1.13 // mount configurations // The container lock should not be held when calling this function. // Changes are only made in-memory and may make changes to containers referenced // by `container.HostConfig.VolumesFrom` func (daemon *Daemon) backportMountSpec(container *container.Container) { container.Lock() defer container.Unlock() parser := volumemounts.NewParser(container.OS) maybeUpdate := make(map[string]bool) for _, mp := range container.MountPoints { if mp.Spec.Source != "" && mp.Type != "" { continue } maybeUpdate[mp.Destination] = true } if len(maybeUpdate) == 0 { return } mountSpecs := make(map[string]bool, len(container.HostConfig.Mounts)) for _, m := range container.HostConfig.Mounts { mountSpecs[m.Target] = true } binds := make(map[string]*volumemounts.MountPoint, len(container.HostConfig.Binds)) for _, rawSpec := range container.HostConfig.Binds { mp, err := parser.ParseMountRaw(rawSpec, container.HostConfig.VolumeDriver) if err != nil { logrus.WithError(err).Error("Got unexpected error while re-parsing raw volume spec during spec backport") continue } binds[mp.Destination] = mp } volumesFrom := make(map[string]volumemounts.MountPoint) for _, fromSpec := range container.HostConfig.VolumesFrom { from, _, err := parser.ParseVolumesFrom(fromSpec) if err != nil { logrus.WithError(err).WithField("id", container.ID).Error("Error reading volumes-from spec during mount spec backport") continue } fromC, err := daemon.GetContainer(from) if err != nil { logrus.WithError(err).WithField("from-container", from).Error("Error looking up volumes-from container") continue } // make sure from container's specs have been backported daemon.backportMountSpec(fromC) fromC.Lock() for t, mp := range fromC.MountPoints { volumesFrom[t] = *mp } fromC.Unlock() } needsUpdate := func(containerMount, other *volumemounts.MountPoint) bool { if containerMount.Type != other.Type || !reflect.DeepEqual(containerMount.Spec, other.Spec) { return true } return false } // main for _, cm := range container.MountPoints { if !maybeUpdate[cm.Destination] { continue } // nothing to backport if from hostconfig.Mounts if mountSpecs[cm.Destination] { continue } if mp, exists := binds[cm.Destination]; exists { if needsUpdate(cm, mp) { cm.Spec = mp.Spec cm.Type = mp.Type } continue } if cm.Name != "" { if mp, exists := volumesFrom[cm.Destination]; exists { if needsUpdate(cm, &mp) { cm.Spec = mp.Spec cm.Type = mp.Type } continue } if cm.Type != "" { // probably specified via the hostconfig.Mounts continue } // anon volume cm.Type = mounttypes.TypeVolume cm.Spec.Type = mounttypes.TypeVolume } else { if cm.Type != "" { // already updated continue } cm.Type = mounttypes.TypeBind cm.Spec.Type = mounttypes.TypeBind cm.Spec.Source = cm.Source if cm.Propagation != "" { cm.Spec.BindOptions = &mounttypes.BindOptions{ Propagation: cm.Propagation, } } } cm.Spec.Target = cm.Destination cm.Spec.ReadOnly = !cm.RW } } // VolumesService is used to perform volume operations func (daemon *Daemon) VolumesService() *service.VolumesService { return daemon.volumes } type volumeMounter interface { Mount(ctx context.Context, v *types.Volume, ref string) (string, error) Unmount(ctx context.Context, v *types.Volume, ref string) error } type volumeWrapper struct { v *types.Volume s volumeMounter } func (v *volumeWrapper) Name() string { return v.v.Name } func (v *volumeWrapper) DriverName() string { return v.v.Driver } func (v *volumeWrapper) Path() string { return v.v.Mountpoint } func (v *volumeWrapper) Mount(ref string) (string, error) { return v.s.Mount(context.TODO(), v.v, ref) } func (v *volumeWrapper) Unmount(ref string) error { return v.s.Unmount(context.TODO(), v.v, ref) } func (v *volumeWrapper) CreatedAt() (time.Time, error) { return time.Time{}, errors.New("not implemented") } func (v *volumeWrapper) Status() map[string]interface{} { return v.v.Status }