зеркало из https://github.com/microsoft/docker.git
269 строки
6.9 KiB
Go
269 строки
6.9 KiB
Go
package runtime
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import (
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"fmt"
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"github.com/dotcloud/docker/archive"
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"github.com/dotcloud/docker/runtime/execdriver"
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"github.com/dotcloud/docker/utils"
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"io/ioutil"
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"os"
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"path/filepath"
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"strings"
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"syscall"
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)
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type BindMap struct {
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SrcPath string
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DstPath string
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Mode string
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}
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func prepareVolumesForContainer(container *Container) error {
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if container.Volumes == nil || len(container.Volumes) == 0 {
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container.Volumes = make(map[string]string)
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container.VolumesRW = make(map[string]bool)
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if err := applyVolumesFrom(container); err != nil {
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return err
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}
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}
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if err := createVolumes(container); err != nil {
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return err
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}
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return nil
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}
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func setupMountsForContainer(container *Container, envPath string) error {
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mounts := []execdriver.Mount{
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{container.runtime.sysInitPath, "/.dockerinit", false, true},
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{envPath, "/.dockerenv", false, true},
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{container.ResolvConfPath, "/etc/resolv.conf", false, true},
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}
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if container.HostnamePath != "" && container.HostsPath != "" {
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mounts = append(mounts, execdriver.Mount{container.HostnamePath, "/etc/hostname", false, true})
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mounts = append(mounts, execdriver.Mount{container.HostsPath, "/etc/hosts", false, true})
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}
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// Mount user specified volumes
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// Note, these are not private because you may want propagation of (un)mounts from host
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// volumes. For instance if you use -v /usr:/usr and the host later mounts /usr/share you
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// want this new mount in the container
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for r, v := range container.Volumes {
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mounts = append(mounts, execdriver.Mount{v, r, container.VolumesRW[r], false})
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}
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container.command.Mounts = mounts
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return nil
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}
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func applyVolumesFrom(container *Container) error {
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if container.Config.VolumesFrom != "" {
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for _, containerSpec := range strings.Split(container.Config.VolumesFrom, ",") {
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var (
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mountRW = true
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specParts = strings.SplitN(containerSpec, ":", 2)
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)
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switch len(specParts) {
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case 0:
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return fmt.Errorf("Malformed volumes-from specification: %s", container.Config.VolumesFrom)
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case 2:
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switch specParts[1] {
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case "ro":
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mountRW = false
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case "rw": // mountRW is already true
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default:
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return fmt.Errorf("Malformed volumes-from specification: %s", containerSpec)
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}
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}
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c := container.runtime.Get(specParts[0])
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if c == nil {
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return fmt.Errorf("Container %s not found. Impossible to mount its volumes", container.ID)
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}
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for volPath, id := range c.Volumes {
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if _, exists := container.Volumes[volPath]; exists {
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continue
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}
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if err := os.MkdirAll(filepath.Join(container.basefs, volPath), 0755); err != nil {
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return err
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}
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container.Volumes[volPath] = id
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if isRW, exists := c.VolumesRW[volPath]; exists {
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container.VolumesRW[volPath] = isRW && mountRW
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}
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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 getBindMap(container *Container) (map[string]BindMap, error) {
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var (
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// Create the requested bind mounts
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binds = make(map[string]BindMap)
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// Define illegal container destinations
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illegalDsts = []string{"/", "."}
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)
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for _, bind := range container.hostConfig.Binds {
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// FIXME: factorize bind parsing in parseBind
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var (
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src, dst, mode string
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arr = strings.Split(bind, ":")
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)
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if len(arr) == 2 {
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src = arr[0]
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dst = arr[1]
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mode = "rw"
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} else if len(arr) == 3 {
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src = arr[0]
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dst = arr[1]
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mode = arr[2]
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} else {
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return nil, fmt.Errorf("Invalid bind specification: %s", bind)
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}
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// Bail if trying to mount to an illegal destination
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for _, illegal := range illegalDsts {
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if dst == illegal {
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return nil, fmt.Errorf("Illegal bind destination: %s", dst)
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}
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}
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bindMap := BindMap{
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SrcPath: src,
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DstPath: dst,
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Mode: mode,
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}
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binds[filepath.Clean(dst)] = bindMap
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}
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return binds, nil
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}
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func createVolumes(container *Container) error {
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binds, err := getBindMap(container)
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if err != nil {
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return err
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}
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volumesDriver := container.runtime.volumes.Driver()
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// Create the requested volumes if they don't exist
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for volPath := range container.Config.Volumes {
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volPath = filepath.Clean(volPath)
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volIsDir := true
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// Skip existing volumes
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if _, exists := container.Volumes[volPath]; exists {
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continue
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}
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var srcPath string
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var isBindMount bool
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srcRW := false
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// If an external bind is defined for this volume, use that as a source
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if bindMap, exists := binds[volPath]; exists {
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isBindMount = true
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srcPath = bindMap.SrcPath
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if strings.ToLower(bindMap.Mode) == "rw" {
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srcRW = true
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}
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if stat, err := os.Stat(bindMap.SrcPath); err != nil {
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return err
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} else {
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volIsDir = stat.IsDir()
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}
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// Otherwise create an directory in $ROOT/volumes/ and use that
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} else {
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// Do not pass a container as the parameter for the volume creation.
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// The graph driver using the container's information ( Image ) to
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// create the parent.
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c, err := container.runtime.volumes.Create(nil, "", "", "", "", nil, nil)
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if err != nil {
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return err
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}
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srcPath, err = volumesDriver.Get(c.ID)
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if err != nil {
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return fmt.Errorf("Driver %s failed to get volume rootfs %s: %s", volumesDriver, c.ID, err)
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}
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srcRW = true // RW by default
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}
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if p, err := filepath.EvalSymlinks(srcPath); err != nil {
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return err
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} else {
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srcPath = p
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}
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container.Volumes[volPath] = srcPath
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container.VolumesRW[volPath] = srcRW
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// Create the mountpoint
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volPath = filepath.Join(container.basefs, volPath)
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rootVolPath, err := utils.FollowSymlinkInScope(volPath, container.basefs)
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if err != nil {
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return err
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}
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if _, err := os.Stat(rootVolPath); err != nil {
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if os.IsNotExist(err) {
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if volIsDir {
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if err := os.MkdirAll(rootVolPath, 0755); err != nil {
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return err
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}
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} else {
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if err := os.MkdirAll(filepath.Dir(rootVolPath), 0755); err != nil {
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return err
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}
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if f, err := os.OpenFile(rootVolPath, os.O_CREATE, 0755); err != nil {
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return err
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} else {
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f.Close()
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}
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}
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}
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}
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// Do not copy or change permissions if we are mounting from the host
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if srcRW && !isBindMount {
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volList, err := ioutil.ReadDir(rootVolPath)
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if err != nil {
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return err
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}
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if len(volList) > 0 {
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srcList, err := ioutil.ReadDir(srcPath)
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if err != nil {
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return err
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}
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if len(srcList) == 0 {
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// If the source volume is empty copy files from the root into the volume
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if err := archive.CopyWithTar(rootVolPath, srcPath); err != nil {
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return err
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}
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var stat syscall.Stat_t
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if err := syscall.Stat(rootVolPath, &stat); err != nil {
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return err
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}
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var srcStat syscall.Stat_t
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if err := syscall.Stat(srcPath, &srcStat); err != nil {
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return err
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}
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// Change the source volume's ownership if it differs from the root
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// files that were just copied
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if stat.Uid != srcStat.Uid || stat.Gid != srcStat.Gid {
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if err := os.Chown(srcPath, int(stat.Uid), int(stat.Gid)); err != nil {
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return err
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}
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}
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}
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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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