235 lines
7.3 KiB
Go
235 lines
7.3 KiB
Go
// +build !windows
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package daemon // import "github.com/docker/docker/daemon"
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import (
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"encoding/json"
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"fmt"
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"os"
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"path/filepath"
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"sort"
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"strconv"
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"strings"
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"github.com/docker/docker/container"
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"github.com/docker/docker/pkg/fileutils"
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"github.com/docker/docker/pkg/mount"
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"github.com/docker/docker/volume"
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"github.com/docker/docker/volume/drivers"
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"github.com/docker/docker/volume/local"
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"github.com/pkg/errors"
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)
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// setupMounts iterates through each of the mount points for a container and
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// calls Setup() on each. It also looks to see if is a network mount such as
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// /etc/resolv.conf, and if it is not, appends it to the array of mounts.
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func (daemon *Daemon) setupMounts(c *container.Container) ([]container.Mount, error) {
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var mounts []container.Mount
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// TODO: tmpfs mounts should be part of Mountpoints
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tmpfsMounts := make(map[string]bool)
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tmpfsMountInfo, err := c.TmpfsMounts()
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if err != nil {
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return nil, err
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}
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for _, m := range tmpfsMountInfo {
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tmpfsMounts[m.Destination] = true
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}
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for _, m := range c.MountPoints {
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if tmpfsMounts[m.Destination] {
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continue
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}
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if err := daemon.lazyInitializeVolume(c.ID, m); err != nil {
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return nil, err
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}
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// If the daemon is being shutdown, we should not let a container start if it is trying to
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// mount the socket the daemon is listening on. During daemon shutdown, the socket
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// (/var/run/docker.sock by default) doesn't exist anymore causing the call to m.Setup to
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// create at directory instead. This in turn will prevent the daemon to restart.
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checkfunc := func(m *volume.MountPoint) error {
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if _, exist := daemon.hosts[m.Source]; exist && daemon.IsShuttingDown() {
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return fmt.Errorf("Could not mount %q to container while the daemon is shutting down", m.Source)
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}
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return nil
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}
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path, err := m.Setup(c.MountLabel, daemon.idMappings.RootPair(), checkfunc)
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if err != nil {
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return nil, err
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}
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if !c.TrySetNetworkMount(m.Destination, path) {
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mnt := container.Mount{
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Source: path,
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Destination: m.Destination,
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Writable: m.RW,
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Propagation: string(m.Propagation),
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}
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if m.Volume != nil {
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attributes := map[string]string{
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"driver": m.Volume.DriverName(),
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"container": c.ID,
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"destination": m.Destination,
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"read/write": strconv.FormatBool(m.RW),
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"propagation": string(m.Propagation),
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}
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daemon.LogVolumeEvent(m.Volume.Name(), "mount", attributes)
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}
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mounts = append(mounts, mnt)
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}
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}
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mounts = sortMounts(mounts)
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netMounts := c.NetworkMounts()
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// if we are going to mount any of the network files from container
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// metadata, the ownership must be set properly for potential container
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// remapped root (user namespaces)
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rootIDs := daemon.idMappings.RootPair()
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for _, mount := range netMounts {
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// we should only modify ownership of network files within our own container
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// metadata repository. If the user specifies a mount path external, it is
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// up to the user to make sure the file has proper ownership for userns
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if strings.Index(mount.Source, daemon.repository) == 0 {
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if err := os.Chown(mount.Source, rootIDs.UID, rootIDs.GID); err != nil {
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return nil, err
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}
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}
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}
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return append(mounts, netMounts...), nil
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}
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// sortMounts sorts an array of mounts in lexicographic order. This ensure that
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// when mounting, the mounts don't shadow other mounts. For example, if mounting
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// /etc and /etc/resolv.conf, /etc/resolv.conf must not be mounted first.
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func sortMounts(m []container.Mount) []container.Mount {
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sort.Sort(mounts(m))
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return m
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}
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// setBindModeIfNull is platform specific processing to ensure the
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// shared mode is set to 'z' if it is null. This is called in the case
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// of processing a named volume and not a typical bind.
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func setBindModeIfNull(bind *volume.MountPoint) {
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if bind.Mode == "" {
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bind.Mode = "z"
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}
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}
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// migrateVolume links the contents of a volume created pre Docker 1.7
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// into the location expected by the local driver.
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// It creates a symlink from DOCKER_ROOT/vfs/dir/VOLUME_ID to DOCKER_ROOT/volumes/VOLUME_ID/_container_data.
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// It preserves the volume json configuration generated pre Docker 1.7 to be able to
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// downgrade from Docker 1.7 to Docker 1.6 without losing volume compatibility.
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func migrateVolume(id, vfs string) error {
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l, err := volumedrivers.GetDriver(volume.DefaultDriverName)
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if err != nil {
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return err
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}
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newDataPath := l.(*local.Root).DataPath(id)
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fi, err := os.Stat(newDataPath)
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if err != nil && !os.IsNotExist(err) {
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return err
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}
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if fi != nil && fi.IsDir() {
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return nil
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}
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return os.Symlink(vfs, newDataPath)
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}
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// verifyVolumesInfo ports volumes configured for the containers pre docker 1.7.
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// It reads the container configuration and creates valid mount points for the old volumes.
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func (daemon *Daemon) verifyVolumesInfo(container *container.Container) error {
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container.Lock()
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defer container.Unlock()
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// Inspect old structures only when we're upgrading from old versions
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// to versions >= 1.7 and the MountPoints has not been populated with volumes data.
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type volumes struct {
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Volumes map[string]string
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VolumesRW map[string]bool
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}
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cfgPath, err := container.ConfigPath()
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if err != nil {
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return err
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}
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f, err := os.Open(cfgPath)
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if err != nil {
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return errors.Wrap(err, "could not open container config")
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}
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defer f.Close()
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var cv volumes
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if err := json.NewDecoder(f).Decode(&cv); err != nil {
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return errors.Wrap(err, "could not decode container config")
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}
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if len(container.MountPoints) == 0 && len(cv.Volumes) > 0 {
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for destination, hostPath := range cv.Volumes {
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vfsPath := filepath.Join(daemon.root, "vfs", "dir")
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rw := cv.VolumesRW != nil && cv.VolumesRW[destination]
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if strings.HasPrefix(hostPath, vfsPath) {
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id := filepath.Base(hostPath)
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v, err := daemon.volumes.CreateWithRef(id, volume.DefaultDriverName, container.ID, nil, nil)
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if err != nil {
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return err
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}
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if err := migrateVolume(id, hostPath); err != nil {
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return err
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}
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container.AddMountPointWithVolume(destination, v, true)
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} else { // Bind mount
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m := volume.MountPoint{Source: hostPath, Destination: destination, RW: rw}
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container.MountPoints[destination] = &m
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}
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}
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}
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return nil
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}
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func (daemon *Daemon) mountVolumes(container *container.Container) error {
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mounts, err := daemon.setupMounts(container)
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if err != nil {
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return err
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}
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for _, m := range mounts {
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dest, err := container.GetResourcePath(m.Destination)
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if err != nil {
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return err
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}
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var stat os.FileInfo
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stat, err = os.Stat(m.Source)
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if err != nil {
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return err
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}
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if err = fileutils.CreateIfNotExists(dest, stat.IsDir()); err != nil {
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return err
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}
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opts := "rbind,ro"
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if m.Writable {
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opts = "rbind,rw"
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}
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if err := mount.Mount(m.Source, dest, bindMountType, opts); err != nil {
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return err
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}
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// mountVolumes() seems to be called for temporary mounts
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// outside the container. Soon these will be unmounted with
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// lazy unmount option and given we have mounted the rbind,
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// all the submounts will propagate if these are shared. If
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// daemon is running in host namespace and has / as shared
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// then these unmounts will propagate and unmount original
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// mount as well. So make all these mounts rprivate.
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// Do not use propagation property of volume as that should
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// apply only when mounting happen inside the container.
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if err := mount.MakeRPrivate(dest); err != nil {
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return err
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}
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}
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return nil
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}
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