package daemon import ( "errors" "os" "path/filepath" "strings" "github.com/docker/docker/container" "github.com/docker/docker/daemon/execdriver" derr "github.com/docker/docker/errors" "github.com/docker/docker/volume" "github.com/docker/engine-api/types" containertypes "github.com/docker/engine-api/types/container" "github.com/opencontainers/runc/libcontainer/label" ) 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 []execdriver.Mount // volumeToAPIType converts a volume.Volume to the type used by the remote API func volumeToAPIType(v volume.Volume) *types.Volume { return &types.Volume{ Name: v.Name(), Driver: v.DriverName(), Mountpoint: v.Path(), } } // 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) error { binds := map[string]bool{} mountPoints := map[string]*volume.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 := volume.ParseVolumesFrom(v) if err != nil { return err } c, err := daemon.GetContainer(containerID) if err != nil { return err } for _, m := range c.MountPoints { cp := &volume.MountPoint{ Name: m.Name, Source: m.Source, RW: m.RW && volume.ReadWrite(mode), Driver: m.Driver, Destination: m.Destination, Propagation: m.Propagation, } if len(cp.Source) == 0 { v, err := daemon.volumes.GetWithRef(cp.Name, cp.Driver, container.ID) if err != nil { return err } cp.Volume = v } mountPoints[cp.Destination] = cp } } // 3. Read bind mounts for _, b := range hostConfig.Binds { // #10618 bind, err := volume.ParseMountSpec(b, hostConfig.VolumeDriver) if err != nil { return err } if binds[bind.Destination] { return derr.ErrorCodeMountDup.WithArgs(bind.Destination) } if len(bind.Name) > 0 && len(bind.Driver) > 0 { // create the volume v, err := daemon.volumes.CreateWithRef(bind.Name, bind.Driver, container.ID, nil) if err != nil { return err } bind.Volume = v bind.Source = v.Path() // bind.Name is an already existing volume, we need to use that here bind.Driver = v.DriverName() bind = setBindModeIfNull(bind) } if label.RelabelNeeded(bind.Mode) { if err := label.Relabel(bind.Source, container.MountLabel, label.IsShared(bind.Mode)); err != nil { return err } } binds[bind.Destination] = true mountPoints[bind.Destination] = bind } container.Lock() // 4. Cleanup old volumes that are about to be reassigned. for _, m := range mountPoints { if m.BackwardsCompatible() { if mp, exists := container.MountPoints[m.Destination]; exists && mp.Volume != nil { daemon.volumes.Dereference(mp.Volume, 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 *volume.MountPoint) error { if len(m.Driver) > 0 && m.Volume == nil { v, err := daemon.volumes.GetWithRef(m.Name, m.Driver, containerID) if err != nil { return err } m.Volume = v } return nil }