Remove LCOW code (step 1)

The LCOW implementation in dockerd has been deprecated in favor of re-implementation
in containerd (in progress). Microsoft started removing the LCOW V1 code from the
build dependencies we use in Microsoft/opengcs (soon to be part of Microsoft/hcshhim),
which means that we need to start removing this code.

This first step removes the lcow graphdriver, the LCOW initialization code, and
some LCOW-related utilities.

Signed-off-by: Sebastiaan van Stijn <[email protected]>

.github/CODEOWNERS

@@ -6,7 +6,6 @@
 builder/**                              @tonistiigi
 contrib/mkimage/**                      @tianon
 daemon/graphdriver/devmapper/**         @rhvgoyal 
-daemon/graphdriver/lcow/**              @johnstep
 daemon/graphdriver/overlay/**           @dmcgowan
 daemon/graphdriver/overlay2/**          @dmcgowan
 daemon/graphdriver/windows/**           @johnstep

api/server/router/image/image_routes.go

@@ -16,7 +16,6 @@ import (
 	"github.com/docker/docker/errdefs"
 	"github.com/docker/docker/pkg/ioutils"
 	"github.com/docker/docker/pkg/streamformatter"
-	"github.com/docker/docker/pkg/system"
 	"github.com/docker/docker/registry"
 	specs "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
@@ -50,9 +49,6 @@ func (s *imageRouter) postImagesCreate(ctx context.Context, w http.ResponseWrite
 			if err != nil {
 				return err
 			}
-			if err := system.ValidatePlatform(sp); err != nil {
-				return err
-			}
 			platform = &sp
 		}
 	}

builder/builder-next/builder.go

@@ -20,7 +20,6 @@ import (
 	"github.com/docker/docker/libnetwork"
 	"github.com/docker/docker/pkg/idtools"
 	"github.com/docker/docker/pkg/streamformatter"
-	"github.com/docker/docker/pkg/system"
 	controlapi "github.com/moby/buildkit/api/services/control"
 	"github.com/moby/buildkit/client"
 	"github.com/moby/buildkit/control"
@@ -299,13 +298,10 @@ func (b *Builder) Build(ctx context.Context, opt backend.BuildConfig) (*builder.
 	if opt.Options.Platform != "" {
 		// same as in newBuilder in builder/dockerfile.builder.go
 		// TODO: remove once opt.Options.Platform is of type specs.Platform
-		sp, err := platforms.Parse(opt.Options.Platform)
+		_, err := platforms.Parse(opt.Options.Platform)
 		if err != nil {
 			return nil, err
 		}
-		if err := system.ValidatePlatform(sp); err != nil {
-			return nil, err
-		}
 		frontendAttrs["platform"] = opt.Options.Platform
 	}
 

builder/dockerfile/builder.go

@@ -159,9 +159,6 @@ func newBuilder(clientCtx context.Context, options builderOptions) (*Builder, er
 		if err != nil {
 			return nil, err
 		}
-		if err := system.ValidatePlatform(sp); err != nil {
-			return nil, err
-		}
 		b.platform = &sp
 	}
 

builder/dockerfile/dispatchers.go

@@ -172,9 +172,6 @@ func initializeStage(d dispatchRequest, cmd *instructions.Stage) error {
 		if err != nil {
 			return errors.Wrapf(err, "failed to parse platform %s", v)
 		}
-		if err := system.ValidatePlatform(p); err != nil {
-			return err
-		}
 		platform = &p
 	}
 
@@ -264,10 +261,7 @@ func (d *dispatchRequest) getImageOrStage(name string, platform *specs.Platform)
 		// from it.
 		if runtime.GOOS == "windows" {
 			if platform == nil || platform.OS == "linux" {
-				if !system.LCOWSupported() {
-					return nil, errors.New("Linux containers are not supported on this system")
-				}
-				imageImage.OS = "linux"
+				return nil, errors.New("Linux containers are not supported on this system")
 			} else if platform.OS == "windows" {
 				return nil, errors.New("Windows does not support FROM scratch")
 			} else {

cmd/dockerd/daemon.go

@@ -117,8 +117,6 @@ func (cli *DaemonCli) start(opts *daemonOptions) (err error) {
 		return fmt.Errorf("dockerd needs to be started with root. To see how to run dockerd in rootless mode with unprivileged user, see the documentation")
 	}
 
-	system.InitLCOW(cli.Config.Experimental)
-
 	if err := setDefaultUmask(); err != nil {
 		return err
 	}

container/container.go

@@ -746,7 +746,7 @@ func (container *Container) CreateDaemonEnvironment(tty bool, linkedEnv []string
 	}
 
 	env := make([]string, 0, envSize)
-	if runtime.GOOS != "windows" || (runtime.GOOS == "windows" && os == "linux") {
+	if runtime.GOOS != "windows" {
 		env = append(env, "PATH="+system.DefaultPathEnv(os))
 		env = append(env, "HOSTNAME="+container.Config.Hostname)
 		if tty {

daemon/create.go

@@ -69,12 +69,6 @@ func (daemon *Daemon) containerCreate(opts createOpts) (containertypes.Container
 		if err == nil {
 			os = img.OS
 		}
-	} else {
-		// This mean scratch. On Windows, we can safely assume that this is a linux
-		// container. On other platforms, it's the host OS (which it already is)
-		if isWindows && system.LCOWSupported() {
-			os = "linux"
-		}
 	}
 
 	warnings, err := daemon.verifyContainerSettings(os, opts.params.HostConfig, opts.params.Config, false)

daemon/daemon_windows.go

@@ -499,19 +499,12 @@ func (daemon *Daemon) runAsHyperVContainer(hostConfig *containertypes.HostConfig
 // conditionalMountOnStart is a platform specific helper function during the
 // container start to call mount.
 func (daemon *Daemon) conditionalMountOnStart(container *container.Container) error {
-
-	// Bail out now for Linux containers. We cannot mount the containers filesystem on the
-	// host as it is a non-Windows filesystem.
-	if system.LCOWSupported() && container.OS != "windows" {
+	if daemon.runAsHyperVContainer(container.HostConfig) {
+		// We do not mount if a Hyper-V container as it needs to be mounted inside the
+		// utility VM, not the host.
 		return nil
 	}
-
-	// We do not mount if a Hyper-V container as it needs to be mounted inside the
-	// utility VM, not the host.
-	if !daemon.runAsHyperVContainer(container.HostConfig) {
-		return daemon.Mount(container)
-	}
-	return nil
+	return daemon.Mount(container)
 }
 
 // conditionalUnmountOnCleanup is a platform specific helper function called