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moby--moby/builder/dockerfile/internals.go
Salahuddin Khan 763d839261 Add ADD/COPY --chown flag support to Windows
This implements chown support on Windows. Built-in accounts as well
as accounts included in the SAM database of the container are supported.

NOTE: IDPair is now named Identity and IDMappings is now named
IdentityMapping.

The following are valid examples:
ADD --chown=Guest . <some directory>
COPY --chown=Administrator . <some directory>
COPY --chown=Guests . <some directory>
COPY --chown=ContainerUser . <some directory>

On Windows an owner is only granted the permission to read the security
descriptor and read/write the discretionary access control list. This
fix also grants read/write and execute permissions to the owner.

Signed-off-by: Salahuddin Khan <salah@docker.com>
2018-08-13 21:59:11 -07:00

500 lines
16 KiB
Go

package dockerfile // import "github.com/docker/docker/builder/dockerfile"
// internals for handling commands. Covers many areas and a lot of
// non-contiguous functionality. Please read the comments.
import (
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"os"
"path"
"path/filepath"
"runtime"
"strings"
"github.com/docker/docker/api/types"
"github.com/docker/docker/api/types/backend"
"github.com/docker/docker/api/types/container"
"github.com/docker/docker/builder"
"github.com/docker/docker/image"
"github.com/docker/docker/pkg/archive"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/pkg/containerfs"
"github.com/docker/docker/pkg/idtools"
"github.com/docker/docker/pkg/stringid"
"github.com/docker/docker/pkg/system"
"github.com/docker/go-connections/nat"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
)
// Archiver defines an interface for copying files from one destination to
// another using Tar/Untar.
type Archiver interface {
TarUntar(src, dst string) error
UntarPath(src, dst string) error
CopyWithTar(src, dst string) error
CopyFileWithTar(src, dst string) error
IdentityMapping() *idtools.IdentityMapping
}
// The builder will use the following interfaces if the container fs implements
// these for optimized copies to and from the container.
type extractor interface {
ExtractArchive(src io.Reader, dst string, opts *archive.TarOptions) error
}
type archiver interface {
ArchivePath(src string, opts *archive.TarOptions) (io.ReadCloser, error)
}
// helper functions to get tar/untar func
func untarFunc(i interface{}) containerfs.UntarFunc {
if ea, ok := i.(extractor); ok {
return ea.ExtractArchive
}
return chrootarchive.Untar
}
func tarFunc(i interface{}) containerfs.TarFunc {
if ap, ok := i.(archiver); ok {
return ap.ArchivePath
}
return archive.TarWithOptions
}
func (b *Builder) getArchiver(src, dst containerfs.Driver) Archiver {
t, u := tarFunc(src), untarFunc(dst)
return &containerfs.Archiver{
SrcDriver: src,
DstDriver: dst,
Tar: t,
Untar: u,
IDMapping: b.idMapping,
}
}
func (b *Builder) commit(dispatchState *dispatchState, comment string) error {
if b.disableCommit {
return nil
}
if !dispatchState.hasFromImage() {
return errors.New("Please provide a source image with `from` prior to commit")
}
runConfigWithCommentCmd := copyRunConfig(dispatchState.runConfig, withCmdComment(comment, dispatchState.operatingSystem))
id, err := b.probeAndCreate(dispatchState, runConfigWithCommentCmd)
if err != nil || id == "" {
return err
}
return b.commitContainer(dispatchState, id, runConfigWithCommentCmd)
}
func (b *Builder) commitContainer(dispatchState *dispatchState, id string, containerConfig *container.Config) error {
if b.disableCommit {
return nil
}
commitCfg := backend.CommitConfig{
Author: dispatchState.maintainer,
// TODO: this copy should be done by Commit()
Config: copyRunConfig(dispatchState.runConfig),
ContainerConfig: containerConfig,
ContainerID: id,
}
imageID, err := b.docker.CommitBuildStep(commitCfg)
dispatchState.imageID = string(imageID)
return err
}
func (b *Builder) exportImage(state *dispatchState, layer builder.RWLayer, parent builder.Image, runConfig *container.Config) error {
newLayer, err := layer.Commit()
if err != nil {
return err
}
// add an image mount without an image so the layer is properly unmounted
// if there is an error before we can add the full mount with image
b.imageSources.Add(newImageMount(nil, newLayer))
parentImage, ok := parent.(*image.Image)
if !ok {
return errors.Errorf("unexpected image type")
}
newImage := image.NewChildImage(parentImage, image.ChildConfig{
Author: state.maintainer,
ContainerConfig: runConfig,
DiffID: newLayer.DiffID(),
Config: copyRunConfig(state.runConfig),
}, parentImage.OS)
// TODO: it seems strange to marshal this here instead of just passing in the
// image struct
config, err := newImage.MarshalJSON()
if err != nil {
return errors.Wrap(err, "failed to encode image config")
}
exportedImage, err := b.docker.CreateImage(config, state.imageID)
if err != nil {
return errors.Wrapf(err, "failed to export image")
}
state.imageID = exportedImage.ImageID()
b.imageSources.Add(newImageMount(exportedImage, newLayer))
return nil
}
func (b *Builder) performCopy(req dispatchRequest, inst copyInstruction) error {
state := req.state
srcHash := getSourceHashFromInfos(inst.infos)
var chownComment string
if inst.chownStr != "" {
chownComment = fmt.Sprintf("--chown=%s", inst.chownStr)
}
commentStr := fmt.Sprintf("%s %s%s in %s ", inst.cmdName, chownComment, srcHash, inst.dest)
// TODO: should this have been using origPaths instead of srcHash in the comment?
runConfigWithCommentCmd := copyRunConfig(
state.runConfig,
withCmdCommentString(commentStr, state.operatingSystem))
hit, err := b.probeCache(state, runConfigWithCommentCmd)
if err != nil || hit {
return err
}
imageMount, err := b.imageSources.Get(state.imageID, true, req.builder.platform)
if err != nil {
return errors.Wrapf(err, "failed to get destination image %q", state.imageID)
}
rwLayer, err := imageMount.NewRWLayer()
if err != nil {
return err
}
defer rwLayer.Release()
destInfo, err := createDestInfo(state.runConfig.WorkingDir, inst, rwLayer, state.operatingSystem)
if err != nil {
return err
}
identity := b.idMapping.RootPair()
// if a chown was requested, perform the steps to get the uid, gid
// translated (if necessary because of user namespaces), and replace
// the root pair with the chown pair for copy operations
if inst.chownStr != "" {
identity, err = parseChownFlag(b, state, inst.chownStr, destInfo.root.Path(), b.idMapping)
if err != nil {
if b.options.Platform != "windows" {
return errors.Wrapf(err, "unable to convert uid/gid chown string to host mapping")
}
return errors.Wrapf(err, "unable to map container user account name to SID")
}
}
for _, info := range inst.infos {
opts := copyFileOptions{
decompress: inst.allowLocalDecompression,
archiver: b.getArchiver(info.root, destInfo.root),
identity: identity,
}
if err := performCopyForInfo(destInfo, info, opts); err != nil {
return errors.Wrapf(err, "failed to copy files")
}
}
return b.exportImage(state, rwLayer, imageMount.Image(), runConfigWithCommentCmd)
}
func createDestInfo(workingDir string, inst copyInstruction, rwLayer builder.RWLayer, platform string) (copyInfo, error) {
// Twiddle the destination when it's a relative path - meaning, make it
// relative to the WORKINGDIR
dest, err := normalizeDest(workingDir, inst.dest, platform)
if err != nil {
return copyInfo{}, errors.Wrapf(err, "invalid %s", inst.cmdName)
}
return copyInfo{root: rwLayer.Root(), path: dest}, nil
}
// normalizeDest normalises the destination of a COPY/ADD command in a
// platform semantically consistent way.
func normalizeDest(workingDir, requested string, platform string) (string, error) {
dest := fromSlash(requested, platform)
endsInSlash := strings.HasSuffix(dest, string(separator(platform)))
if platform != "windows" {
if !path.IsAbs(requested) {
dest = path.Join("/", filepath.ToSlash(workingDir), dest)
// Make sure we preserve any trailing slash
if endsInSlash {
dest += "/"
}
}
return dest, nil
}
// We are guaranteed that the working directory is already consistent,
// However, Windows also has, for now, the limitation that ADD/COPY can
// only be done to the system drive, not any drives that might be present
// as a result of a bind mount.
//
// So... if the path requested is Linux-style absolute (/foo or \\foo),
// we assume it is the system drive. If it is a Windows-style absolute
// (DRIVE:\\foo), error if DRIVE is not C. And finally, ensure we
// strip any configured working directories drive letter so that it
// can be subsequently legitimately converted to a Windows volume-style
// pathname.
// Not a typo - filepath.IsAbs, not system.IsAbs on this next check as
// we only want to validate where the DriveColon part has been supplied.
if filepath.IsAbs(dest) {
if strings.ToUpper(string(dest[0])) != "C" {
return "", fmt.Errorf("Windows does not support destinations not on the system drive (C:)")
}
dest = dest[2:] // Strip the drive letter
}
// Cannot handle relative where WorkingDir is not the system drive.
if len(workingDir) > 0 {
if ((len(workingDir) > 1) && !system.IsAbs(workingDir[2:])) || (len(workingDir) == 1) {
return "", fmt.Errorf("Current WorkingDir %s is not platform consistent", workingDir)
}
if !system.IsAbs(dest) {
if string(workingDir[0]) != "C" {
return "", fmt.Errorf("Windows does not support relative paths when WORKDIR is not the system drive")
}
dest = filepath.Join(string(os.PathSeparator), workingDir[2:], dest)
// Make sure we preserve any trailing slash
if endsInSlash {
dest += string(os.PathSeparator)
}
}
}
return dest, nil
}
// For backwards compat, if there's just one info then use it as the
// cache look-up string, otherwise hash 'em all into one
func getSourceHashFromInfos(infos []copyInfo) string {
if len(infos) == 1 {
return infos[0].hash
}
var hashs []string
for _, info := range infos {
hashs = append(hashs, info.hash)
}
return hashStringSlice("multi", hashs)
}
func hashStringSlice(prefix string, slice []string) string {
hasher := sha256.New()
hasher.Write([]byte(strings.Join(slice, ",")))
return prefix + ":" + hex.EncodeToString(hasher.Sum(nil))
}
type runConfigModifier func(*container.Config)
func withCmd(cmd []string) runConfigModifier {
return func(runConfig *container.Config) {
runConfig.Cmd = cmd
}
}
// withCmdComment sets Cmd to a nop comment string. See withCmdCommentString for
// why there are two almost identical versions of this.
func withCmdComment(comment string, platform string) runConfigModifier {
return func(runConfig *container.Config) {
runConfig.Cmd = append(getShell(runConfig, platform), "#(nop) ", comment)
}
}
// withCmdCommentString exists to maintain compatibility with older versions.
// A few instructions (workdir, copy, add) used a nop comment that is a single arg
// where as all the other instructions used a two arg comment string. This
// function implements the single arg version.
func withCmdCommentString(comment string, platform string) runConfigModifier {
return func(runConfig *container.Config) {
runConfig.Cmd = append(getShell(runConfig, platform), "#(nop) "+comment)
}
}
func withEnv(env []string) runConfigModifier {
return func(runConfig *container.Config) {
runConfig.Env = env
}
}
// withEntrypointOverride sets an entrypoint on runConfig if the command is
// not empty. The entrypoint is left unmodified if command is empty.
//
// The dockerfile RUN instruction expect to run without an entrypoint
// so the runConfig entrypoint needs to be modified accordingly. ContainerCreate
// will change a []string{""} entrypoint to nil, so we probe the cache with the
// nil entrypoint.
func withEntrypointOverride(cmd []string, entrypoint []string) runConfigModifier {
return func(runConfig *container.Config) {
if len(cmd) > 0 {
runConfig.Entrypoint = entrypoint
}
}
}
// withoutHealthcheck disables healthcheck.
//
// The dockerfile RUN instruction expect to run without healthcheck
// so the runConfig Healthcheck needs to be disabled.
func withoutHealthcheck() runConfigModifier {
return func(runConfig *container.Config) {
runConfig.Healthcheck = &container.HealthConfig{
Test: []string{"NONE"},
}
}
}
func copyRunConfig(runConfig *container.Config, modifiers ...runConfigModifier) *container.Config {
copy := *runConfig
copy.Cmd = copyStringSlice(runConfig.Cmd)
copy.Env = copyStringSlice(runConfig.Env)
copy.Entrypoint = copyStringSlice(runConfig.Entrypoint)
copy.OnBuild = copyStringSlice(runConfig.OnBuild)
copy.Shell = copyStringSlice(runConfig.Shell)
if copy.Volumes != nil {
copy.Volumes = make(map[string]struct{}, len(runConfig.Volumes))
for k, v := range runConfig.Volumes {
copy.Volumes[k] = v
}
}
if copy.ExposedPorts != nil {
copy.ExposedPorts = make(nat.PortSet, len(runConfig.ExposedPorts))
for k, v := range runConfig.ExposedPorts {
copy.ExposedPorts[k] = v
}
}
if copy.Labels != nil {
copy.Labels = make(map[string]string, len(runConfig.Labels))
for k, v := range runConfig.Labels {
copy.Labels[k] = v
}
}
for _, modifier := range modifiers {
modifier(&copy)
}
return &copy
}
func copyStringSlice(orig []string) []string {
if orig == nil {
return nil
}
return append([]string{}, orig...)
}
// getShell is a helper function which gets the right shell for prefixing the
// shell-form of RUN, ENTRYPOINT and CMD instructions
func getShell(c *container.Config, os string) []string {
if 0 == len(c.Shell) {
return append([]string{}, defaultShellForOS(os)[:]...)
}
return append([]string{}, c.Shell[:]...)
}
func (b *Builder) probeCache(dispatchState *dispatchState, runConfig *container.Config) (bool, error) {
cachedID, err := b.imageProber.Probe(dispatchState.imageID, runConfig)
if cachedID == "" || err != nil {
return false, err
}
fmt.Fprint(b.Stdout, " ---> Using cache\n")
dispatchState.imageID = cachedID
return true, nil
}
var defaultLogConfig = container.LogConfig{Type: "none"}
func (b *Builder) probeAndCreate(dispatchState *dispatchState, runConfig *container.Config) (string, error) {
if hit, err := b.probeCache(dispatchState, runConfig); err != nil || hit {
return "", err
}
return b.create(runConfig)
}
func (b *Builder) create(runConfig *container.Config) (string, error) {
logrus.Debugf("[BUILDER] Command to be executed: %v", runConfig.Cmd)
isWCOW := runtime.GOOS == "windows" && b.platform != nil && b.platform.OS == "windows"
hostConfig := hostConfigFromOptions(b.options, isWCOW)
container, err := b.containerManager.Create(runConfig, hostConfig)
if err != nil {
return "", err
}
// TODO: could this be moved into containerManager.Create() ?
for _, warning := range container.Warnings {
fmt.Fprintf(b.Stdout, " ---> [Warning] %s\n", warning)
}
fmt.Fprintf(b.Stdout, " ---> Running in %s\n", stringid.TruncateID(container.ID))
return container.ID, nil
}
func hostConfigFromOptions(options *types.ImageBuildOptions, isWCOW bool) *container.HostConfig {
resources := container.Resources{
CgroupParent: options.CgroupParent,
CPUShares: options.CPUShares,
CPUPeriod: options.CPUPeriod,
CPUQuota: options.CPUQuota,
CpusetCpus: options.CPUSetCPUs,
CpusetMems: options.CPUSetMems,
Memory: options.Memory,
MemorySwap: options.MemorySwap,
Ulimits: options.Ulimits,
}
hc := &container.HostConfig{
SecurityOpt: options.SecurityOpt,
Isolation: options.Isolation,
ShmSize: options.ShmSize,
Resources: resources,
NetworkMode: container.NetworkMode(options.NetworkMode),
// Set a log config to override any default value set on the daemon
LogConfig: defaultLogConfig,
ExtraHosts: options.ExtraHosts,
}
// For WCOW, the default of 20GB hard-coded in the platform
// is too small for builder scenarios where many users are
// using RUN statements to install large amounts of data.
// Use 127GB as that's the default size of a VHD in Hyper-V.
if isWCOW {
hc.StorageOpt = make(map[string]string)
hc.StorageOpt["size"] = "127GB"
}
return hc
}
// fromSlash works like filepath.FromSlash but with a given OS platform field
func fromSlash(path, platform string) string {
if platform == "windows" {
return strings.Replace(path, "/", "\\", -1)
}
return path
}
// separator returns a OS path separator for the given OS platform
func separator(platform string) byte {
if platform == "windows" {
return '\\'
}
return '/'
}