go.mod github.com/Microsoft/hcsshim v0.8.16

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

vendor/github.com/Microsoft/hcsshim/computestorage/attach.go

@@ -0,0 +1,38 @@
+package computestorage
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+)
+
+// AttachLayerStorageFilter sets up the layer storage filter on a writable
+// container layer.
+//
+// `layerPath` is a path to a directory the writable layer is mounted. If the
+// path does not end in a `\` the platform will append it automatically.
+//
+// `layerData` is the parent read-only layer data.
+func AttachLayerStorageFilter(ctx context.Context, layerPath string, layerData LayerData) (err error) {
+	title := "hcsshim.AttachLayerStorageFilter"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+	)
+
+	bytes, err := json.Marshal(layerData)
+	if err != nil {
+		return err
+	}
+
+	err = hcsAttachLayerStorageFilter(layerPath, string(bytes))
+	if err != nil {
+		return errors.Wrap(err, "failed to attach layer storage filter")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/destroy.go

@@ -0,0 +1,26 @@
+package computestorage
+
+import (
+	"context"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+)
+
+// DestroyLayer deletes a container layer.
+//
+// `layerPath` is a path to a directory containing the layer to export.
+func DestroyLayer(ctx context.Context, layerPath string) (err error) {
+	title := "hcsshim.DestroyLayer"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(trace.StringAttribute("layerPath", layerPath))
+
+	err = hcsDestroyLayer(layerPath)
+	if err != nil {
+		return errors.Wrap(err, "failed to destroy layer")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/detach.go

@@ -0,0 +1,26 @@
+package computestorage
+
+import (
+	"context"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+)
+
+// DetachLayerStorageFilter detaches the layer storage filter on a writable container layer.
+//
+// `layerPath` is a path to a directory containing the layer to export.
+func DetachLayerStorageFilter(ctx context.Context, layerPath string) (err error) {
+	title := "hcsshim.DetachLayerStorageFilter"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(trace.StringAttribute("layerPath", layerPath))
+
+	err = hcsDetachLayerStorageFilter(layerPath)
+	if err != nil {
+		return errors.Wrap(err, "failed to detach layer storage filter")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/export.go

@@ -0,0 +1,46 @@
+package computestorage
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+)
+
+// ExportLayer exports a container layer.
+//
+// `layerPath` is a path to a directory containing the layer to export.
+//
+// `exportFolderPath` is a pre-existing folder to export the layer to.
+//
+// `layerData` is the parent layer data.
+//
+// `options` are the export options applied to the exported layer.
+func ExportLayer(ctx context.Context, layerPath, exportFolderPath string, layerData LayerData, options ExportLayerOptions) (err error) {
+	title := "hcsshim.ExportLayer"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+		trace.StringAttribute("exportFolderPath", exportFolderPath),
+	)
+
+	ldbytes, err := json.Marshal(layerData)
+	if err != nil {
+		return err
+	}
+
+	obytes, err := json.Marshal(options)
+	if err != nil {
+		return err
+	}
+
+	err = hcsExportLayer(layerPath, exportFolderPath, string(ldbytes), string(obytes))
+	if err != nil {
+		return errors.Wrap(err, "failed to export layer")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/format.go

@@ -0,0 +1,26 @@
+package computestorage
+
+import (
+	"context"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+	"golang.org/x/sys/windows"
+)
+
+// FormatWritableLayerVhd formats a virtual disk for use as a writable container layer.
+//
+// If the VHD is not mounted it will be temporarily mounted.
+func FormatWritableLayerVhd(ctx context.Context, vhdHandle windows.Handle) (err error) {
+	title := "hcsshim.FormatWritableLayerVhd"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+
+	err = hcsFormatWritableLayerVhd(vhdHandle)
+	if err != nil {
+		return errors.Wrap(err, "failed to format writable layer vhd")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/helpers.go

@@ -0,0 +1,193 @@
+package computestorage
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"github.com/Microsoft/go-winio/pkg/security"
+	"github.com/Microsoft/go-winio/vhd"
+	"github.com/pkg/errors"
+	"golang.org/x/sys/windows"
+)
+
+const defaultVHDXBlockSizeInMB = 1
+
+// SetupContainerBaseLayer is a helper to setup a containers scratch. It
+// will create and format the vhdx's inside and the size is configurable with the sizeInGB
+// parameter.
+//
+// `layerPath` is the path to the base container layer on disk.
+//
+// `baseVhdPath` is the path to where the base vhdx for the base layer should be created.
+//
+// `diffVhdPath` is the path where the differencing disk for the base layer should be created.
+//
+// `sizeInGB` is the size in gigabytes to make the base vhdx.
+func SetupContainerBaseLayer(ctx context.Context, layerPath, baseVhdPath, diffVhdPath string, sizeInGB uint64) (err error) {
+	var (
+		hivesPath  = filepath.Join(layerPath, "Hives")
+		layoutPath = filepath.Join(layerPath, "Layout")
+	)
+
+	// We need to remove the hives directory and layout file as `SetupBaseOSLayer` fails if these files
+	// already exist. `SetupBaseOSLayer` will create these files internally. We also remove the base and
+	// differencing disks if they exist in case we're asking for a different size.
+	if _, err := os.Stat(hivesPath); err == nil {
+		if err := os.RemoveAll(hivesPath); err != nil {
+			return errors.Wrap(err, "failed to remove prexisting hives directory")
+		}
+	}
+	if _, err := os.Stat(layoutPath); err == nil {
+		if err := os.RemoveAll(layoutPath); err != nil {
+			return errors.Wrap(err, "failed to remove prexisting layout file")
+		}
+	}
+
+	if _, err := os.Stat(baseVhdPath); err == nil {
+		if err := os.RemoveAll(baseVhdPath); err != nil {
+			return errors.Wrap(err, "failed to remove base vhdx path")
+		}
+	}
+	if _, err := os.Stat(diffVhdPath); err == nil {
+		if err := os.RemoveAll(diffVhdPath); err != nil {
+			return errors.Wrap(err, "failed to remove differencing vhdx")
+		}
+	}
+
+	createParams := &vhd.CreateVirtualDiskParameters{
+		Version: 2,
+		Version2: vhd.CreateVersion2{
+			MaximumSize:      sizeInGB * 1024 * 1024 * 1024,
+			BlockSizeInBytes: defaultVHDXBlockSizeInMB * 1024 * 1024,
+		},
+	}
+	handle, err := vhd.CreateVirtualDisk(baseVhdPath, vhd.VirtualDiskAccessNone, vhd.CreateVirtualDiskFlagNone, createParams)
+	if err != nil {
+		return errors.Wrap(err, "failed to create vhdx")
+	}
+
+	defer func() {
+		if err != nil {
+			_ = syscall.CloseHandle(handle)
+			os.RemoveAll(baseVhdPath)
+			os.RemoveAll(diffVhdPath)
+		}
+	}()
+
+	if err = FormatWritableLayerVhd(ctx, windows.Handle(handle)); err != nil {
+		return err
+	}
+	// Base vhd handle must be closed before calling SetupBaseLayer in case of Container layer
+	if err = syscall.CloseHandle(handle); err != nil {
+		return errors.Wrap(err, "failed to close vhdx handle")
+	}
+
+	options := OsLayerOptions{
+		Type: OsLayerTypeContainer,
+	}
+
+	// SetupBaseOSLayer expects an empty vhd handle for a container layer and will
+	// error out otherwise.
+	if err = SetupBaseOSLayer(ctx, layerPath, 0, options); err != nil {
+		return err
+	}
+	// Create the differencing disk that will be what's copied for the final rw layer
+	// for a container.
+	if err = vhd.CreateDiffVhd(diffVhdPath, baseVhdPath, defaultVHDXBlockSizeInMB); err != nil {
+		return errors.Wrap(err, "failed to create differencing disk")
+	}
+
+	if err = security.GrantVmGroupAccess(baseVhdPath); err != nil {
+		return errors.Wrapf(err, "failed to grant vm group access to %s", baseVhdPath)
+	}
+	if err = security.GrantVmGroupAccess(diffVhdPath); err != nil {
+		return errors.Wrapf(err, "failed to grant vm group access to %s", diffVhdPath)
+	}
+	return nil
+}
+
+// SetupUtilityVMBaseLayer is a helper to setup a UVMs scratch space. It will create and format
+// the vhdx inside and the size is configurable by the sizeInGB parameter.
+//
+// `uvmPath` is the path to the UtilityVM filesystem.
+//
+// `baseVhdPath` is the path to where the base vhdx for the UVM should be created.
+//
+// `diffVhdPath` is the path where the differencing disk for the UVM should be created.
+//
+// `sizeInGB` specifies the size in gigabytes to make the base vhdx.
+func SetupUtilityVMBaseLayer(ctx context.Context, uvmPath, baseVhdPath, diffVhdPath string, sizeInGB uint64) (err error) {
+	// Remove the base and differencing disks if they exist in case we're asking for a different size.
+	if _, err := os.Stat(baseVhdPath); err == nil {
+		if err := os.RemoveAll(baseVhdPath); err != nil {
+			return errors.Wrap(err, "failed to remove base vhdx")
+		}
+	}
+	if _, err := os.Stat(diffVhdPath); err == nil {
+		if err := os.RemoveAll(diffVhdPath); err != nil {
+			return errors.Wrap(err, "failed to remove differencing vhdx")
+		}
+	}
+
+	// Just create the vhdx for utilityVM layer, no need to format it.
+	createParams := &vhd.CreateVirtualDiskParameters{
+		Version: 2,
+		Version2: vhd.CreateVersion2{
+			MaximumSize:      sizeInGB * 1024 * 1024 * 1024,
+			BlockSizeInBytes: defaultVHDXBlockSizeInMB * 1024 * 1024,
+		},
+	}
+	handle, err := vhd.CreateVirtualDisk(baseVhdPath, vhd.VirtualDiskAccessNone, vhd.CreateVirtualDiskFlagNone, createParams)
+	if err != nil {
+		return errors.Wrap(err, "failed to create vhdx")
+	}
+
+	defer func() {
+		if err != nil {
+			_ = syscall.CloseHandle(handle)
+			os.RemoveAll(baseVhdPath)
+			os.RemoveAll(diffVhdPath)
+		}
+	}()
+
+	// If it is a UtilityVM layer then the base vhdx must be attached when calling
+	// `SetupBaseOSLayer`
+	attachParams := &vhd.AttachVirtualDiskParameters{
+		Version: 2,
+	}
+	if err := vhd.AttachVirtualDisk(handle, vhd.AttachVirtualDiskFlagNone, attachParams); err != nil {
+		return errors.Wrapf(err, "failed to attach virtual disk")
+	}
+
+	options := OsLayerOptions{
+		Type: OsLayerTypeVM,
+	}
+	if err := SetupBaseOSLayer(ctx, uvmPath, windows.Handle(handle), options); err != nil {
+		return err
+	}
+
+	// Detach and close the handle after setting up the layer as we don't need the handle
+	// for anything else and we no longer need to be attached either.
+	if err = vhd.DetachVirtualDisk(handle); err != nil {
+		return errors.Wrap(err, "failed to detach vhdx")
+	}
+	if err = syscall.CloseHandle(handle); err != nil {
+		return errors.Wrap(err, "failed to close vhdx handle")
+	}
+
+	// Create the differencing disk that will be what's copied for the final rw layer
+	// for a container.
+	if err = vhd.CreateDiffVhd(diffVhdPath, baseVhdPath, defaultVHDXBlockSizeInMB); err != nil {
+		return errors.Wrap(err, "failed to create differencing disk")
+	}
+
+	if err := security.GrantVmGroupAccess(baseVhdPath); err != nil {
+		return errors.Wrapf(err, "failed to grant vm group access to %s", baseVhdPath)
+	}
+	if err := security.GrantVmGroupAccess(diffVhdPath); err != nil {
+		return errors.Wrapf(err, "failed to grant vm group access to %s", diffVhdPath)
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/import.go

@@ -0,0 +1,41 @@
+package computestorage
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+)
+
+// ImportLayer imports a container layer.
+//
+// `layerPath` is a path to a directory to import the layer to. If the directory
+// does not exist it will be automatically created.
+//
+// `sourceFolderpath` is a pre-existing folder that contains the layer to
+// import.
+//
+// `layerData` is the parent layer data.
+func ImportLayer(ctx context.Context, layerPath, sourceFolderPath string, layerData LayerData) (err error) {
+	title := "hcsshim.ImportLayer"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+		trace.StringAttribute("sourceFolderPath", sourceFolderPath),
+	)
+
+	bytes, err := json.Marshal(layerData)
+	if err != nil {
+		return err
+	}
+
+	err = hcsImportLayer(layerPath, sourceFolderPath, string(bytes))
+	if err != nil {
+		return errors.Wrap(err, "failed to import layer")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/initialize.go

@@ -0,0 +1,38 @@
+package computestorage
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+)
+
+// InitializeWritableLayer initializes a writable layer for a container.
+//
+// `layerPath` is a path to a directory the layer is mounted. If the
+// path does not end in a `\` the platform will append it automatically.
+//
+// `layerData` is the parent read-only layer data.
+func InitializeWritableLayer(ctx context.Context, layerPath string, layerData LayerData) (err error) {
+	title := "hcsshim.InitializeWritableLayer"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+	)
+
+	bytes, err := json.Marshal(layerData)
+	if err != nil {
+		return err
+	}
+
+	// Options are not used in the platform as of RS5
+	err = hcsInitializeWritableLayer(layerPath, string(bytes), "")
+	if err != nil {
+		return errors.Wrap(err, "failed to intitialize container layer")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/mount.go

@@ -0,0 +1,27 @@
+package computestorage
+
+import (
+	"context"
+
+	"github.com/Microsoft/hcsshim/internal/interop"
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+	"golang.org/x/sys/windows"
+)
+
+// GetLayerVhdMountPath returns the volume path for a virtual disk of a writable container layer.
+func GetLayerVhdMountPath(ctx context.Context, vhdHandle windows.Handle) (path string, err error) {
+	title := "hcsshim.GetLayerVhdMountPath"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+
+	var mountPath *uint16
+	err = hcsGetLayerVhdMountPath(vhdHandle, &mountPath)
+	if err != nil {
+		return "", errors.Wrap(err, "failed to get vhd mount path")
+	}
+	path = interop.ConvertAndFreeCoTaskMemString(mountPath)
+	return path, nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/setup.go

@@ -0,0 +1,74 @@
+package computestorage
+
+import (
+	"context"
+	"encoding/json"
+
+	"github.com/Microsoft/hcsshim/internal/oc"
+	"github.com/Microsoft/hcsshim/osversion"
+	"github.com/pkg/errors"
+	"go.opencensus.io/trace"
+	"golang.org/x/sys/windows"
+)
+
+// SetupBaseOSLayer sets up a layer that contains a base OS for a container.
+//
+// `layerPath` is a path to a directory containing the layer.
+//
+// `vhdHandle` is an empty file handle of `options.Type == OsLayerTypeContainer`
+// or else it is a file handle to the 'SystemTemplateBase.vhdx' if `options.Type
+// == OsLayerTypeVm`.
+//
+// `options` are the options applied while processing the layer.
+func SetupBaseOSLayer(ctx context.Context, layerPath string, vhdHandle windows.Handle, options OsLayerOptions) (err error) {
+	title := "hcsshim.SetupBaseOSLayer"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+	)
+
+	bytes, err := json.Marshal(options)
+	if err != nil {
+		return err
+	}
+
+	err = hcsSetupBaseOSLayer(layerPath, vhdHandle, string(bytes))
+	if err != nil {
+		return errors.Wrap(err, "failed to setup base OS layer")
+	}
+	return nil
+}
+
+// SetupBaseOSVolume sets up a volume that contains a base OS for a container.
+//
+// `layerPath` is a path to a directory containing the layer.
+//
+// `volumePath` is the path to the volume to be used for setup.
+//
+// `options` are the options applied while processing the layer.
+func SetupBaseOSVolume(ctx context.Context, layerPath, volumePath string, options OsLayerOptions) (err error) {
+	if osversion.Get().Build < 19645 {
+		return errors.New("SetupBaseOSVolume is not present on builds older than 19645")
+	}
+	title := "hcsshim.SetupBaseOSVolume"
+	ctx, span := trace.StartSpan(ctx, title) //nolint:ineffassign,staticcheck
+	defer span.End()
+	defer func() { oc.SetSpanStatus(span, err) }()
+	span.AddAttributes(
+		trace.StringAttribute("layerPath", layerPath),
+		trace.StringAttribute("volumePath", volumePath),
+	)
+
+	bytes, err := json.Marshal(options)
+	if err != nil {
+		return err
+	}
+
+	err = hcsSetupBaseOSVolume(layerPath, volumePath, string(bytes))
+	if err != nil {
+		return errors.Wrap(err, "failed to setup base OS layer")
+	}
+	return nil
+}

vendor/github.com/Microsoft/hcsshim/computestorage/storage.go

@@ -0,0 +1,50 @@
+// Package computestorage is a wrapper around the HCS storage APIs. These are new storage APIs introduced
+// separate from the original graphdriver calls intended to give more freedom around creating
+// and managing container layers and scratch spaces.
+package computestorage
+
+import (
+	hcsschema "github.com/Microsoft/hcsshim/internal/schema2"
+)
+
+//go:generate go run ../mksyscall_windows.go -output zsyscall_windows.go storage.go
+
+//sys hcsImportLayer(layerPath string, sourceFolderPath string, layerData string) (hr error) = computestorage.HcsImportLayer?
+//sys hcsExportLayer(layerPath string, exportFolderPath string, layerData string, options string) (hr error) = computestorage.HcsExportLayer?
+//sys hcsDestroyLayer(layerPath string) (hr error) = computestorage.HcsDestoryLayer?
+//sys hcsSetupBaseOSLayer(layerPath string, handle windows.Handle, options string) (hr error) = computestorage.HcsSetupBaseOSLayer?
+//sys hcsInitializeWritableLayer(writableLayerPath string, layerData string, options string) (hr error) = computestorage.HcsInitializeWritableLayer?
+//sys hcsAttachLayerStorageFilter(layerPath string, layerData string) (hr error) = computestorage.HcsAttachLayerStorageFilter?
+//sys hcsDetachLayerStorageFilter(layerPath string) (hr error) = computestorage.HcsDetachLayerStorageFilter?
+//sys hcsFormatWritableLayerVhd(handle windows.Handle) (hr error) = computestorage.HcsFormatWritableLayerVhd?
+//sys hcsGetLayerVhdMountPath(vhdHandle windows.Handle, mountPath **uint16) (hr error) = computestorage.HcsGetLayerVhdMountPath?
+//sys hcsSetupBaseOSVolume(layerPath string, volumePath string, options string) (hr error) = computestorage.HcsSetupBaseOSVolume?
+
+// LayerData is the data used to describe parent layer information.
+type LayerData struct {
+	SchemaVersion hcsschema.Version `json:"SchemaVersion,omitempty"`
+	Layers        []hcsschema.Layer `json:"Layers,omitempty"`
+}
+
+// ExportLayerOptions are the set of options that are used with the `computestorage.HcsExportLayer` syscall.
+type ExportLayerOptions struct {
+	IsWritableLayer bool `json:"IsWritableLayer,omitempty"`
+}
+
+// OsLayerType is the type of layer being operated on.
+type OsLayerType string
+
+const (
+	// OsLayerTypeContainer is a container layer.
+	OsLayerTypeContainer OsLayerType = "Container"
+	// OsLayerTypeVM is a virtual machine layer.
+	OsLayerTypeVM OsLayerType = "Vm"
+)
+
+// OsLayerOptions are the set of options that are used with the `SetupBaseOSLayer` and
+// `SetupBaseOSVolume` calls.
+type OsLayerOptions struct {
+	Type                       OsLayerType `json:"Type,omitempty"`
+	DisableCiCacheOptimization bool        `json:"DisableCiCacheOptimization,omitempty"`
+	SkipUpdateBcdForBoot       bool        `json:"SkipUpdateBcdForBoot,omitempty"`
+}

vendor/github.com/Microsoft/hcsshim/computestorage/zsyscall_windows.go

@@ -0,0 +1,319 @@
+// Code generated mksyscall_windows.exe DO NOT EDIT
+
+package computestorage
+
+import (
+	"syscall"
+	"unsafe"
+
+	"golang.org/x/sys/windows"
+)
+
+var _ unsafe.Pointer
+
+// Do the interface allocations only once for common
+// Errno values.
+const (
+	errnoERROR_IO_PENDING = 997
+)
+
+var (
+	errERROR_IO_PENDING error = syscall.Errno(errnoERROR_IO_PENDING)
+)
+
+// errnoErr returns common boxed Errno values, to prevent
+// allocations at runtime.
+func errnoErr(e syscall.Errno) error {
+	switch e {
+	case 0:
+		return nil
+	case errnoERROR_IO_PENDING:
+		return errERROR_IO_PENDING
+	}
+	// TODO: add more here, after collecting data on the common
+	// error values see on Windows. (perhaps when running
+	// all.bat?)
+	return e
+}
+
+var (
+	modcomputestorage = windows.NewLazySystemDLL("computestorage.dll")
+
+	procHcsImportLayer              = modcomputestorage.NewProc("HcsImportLayer")
+	procHcsExportLayer              = modcomputestorage.NewProc("HcsExportLayer")
+	procHcsDestoryLayer             = modcomputestorage.NewProc("HcsDestoryLayer")
+	procHcsSetupBaseOSLayer         = modcomputestorage.NewProc("HcsSetupBaseOSLayer")
+	procHcsInitializeWritableLayer  = modcomputestorage.NewProc("HcsInitializeWritableLayer")
+	procHcsAttachLayerStorageFilter = modcomputestorage.NewProc("HcsAttachLayerStorageFilter")
+	procHcsDetachLayerStorageFilter = modcomputestorage.NewProc("HcsDetachLayerStorageFilter")
+	procHcsFormatWritableLayerVhd   = modcomputestorage.NewProc("HcsFormatWritableLayerVhd")
+	procHcsGetLayerVhdMountPath     = modcomputestorage.NewProc("HcsGetLayerVhdMountPath")
+	procHcsSetupBaseOSVolume        = modcomputestorage.NewProc("HcsSetupBaseOSVolume")
+)
+
+func hcsImportLayer(layerPath string, sourceFolderPath string, layerData string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, hr = syscall.UTF16PtrFromString(sourceFolderPath)
+	if hr != nil {
+		return
+	}
+	var _p2 *uint16
+	_p2, hr = syscall.UTF16PtrFromString(layerData)
+	if hr != nil {
+		return
+	}
+	return _hcsImportLayer(_p0, _p1, _p2)
+}
+
+func _hcsImportLayer(layerPath *uint16, sourceFolderPath *uint16, layerData *uint16) (hr error) {
+	if hr = procHcsImportLayer.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsImportLayer.Addr(), 3, uintptr(unsafe.Pointer(layerPath)), uintptr(unsafe.Pointer(sourceFolderPath)), uintptr(unsafe.Pointer(layerData)))
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsExportLayer(layerPath string, exportFolderPath string, layerData string, options string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, hr = syscall.UTF16PtrFromString(exportFolderPath)
+	if hr != nil {
+		return
+	}
+	var _p2 *uint16
+	_p2, hr = syscall.UTF16PtrFromString(layerData)
+	if hr != nil {
+		return
+	}
+	var _p3 *uint16
+	_p3, hr = syscall.UTF16PtrFromString(options)
+	if hr != nil {
+		return
+	}
+	return _hcsExportLayer(_p0, _p1, _p2, _p3)
+}
+
+func _hcsExportLayer(layerPath *uint16, exportFolderPath *uint16, layerData *uint16, options *uint16) (hr error) {
+	if hr = procHcsExportLayer.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall6(procHcsExportLayer.Addr(), 4, uintptr(unsafe.Pointer(layerPath)), uintptr(unsafe.Pointer(exportFolderPath)), uintptr(unsafe.Pointer(layerData)), uintptr(unsafe.Pointer(options)), 0, 0)
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsDestroyLayer(layerPath string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	return _hcsDestroyLayer(_p0)
+}
+
+func _hcsDestroyLayer(layerPath *uint16) (hr error) {
+	if hr = procHcsDestoryLayer.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsDestoryLayer.Addr(), 1, uintptr(unsafe.Pointer(layerPath)), 0, 0)
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsSetupBaseOSLayer(layerPath string, handle windows.Handle, options string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, hr = syscall.UTF16PtrFromString(options)
+	if hr != nil {
+		return
+	}
+	return _hcsSetupBaseOSLayer(_p0, handle, _p1)
+}
+
+func _hcsSetupBaseOSLayer(layerPath *uint16, handle windows.Handle, options *uint16) (hr error) {
+	if hr = procHcsSetupBaseOSLayer.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsSetupBaseOSLayer.Addr(), 3, uintptr(unsafe.Pointer(layerPath)), uintptr(handle), uintptr(unsafe.Pointer(options)))
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsInitializeWritableLayer(writableLayerPath string, layerData string, options string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(writableLayerPath)
+	if hr != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, hr = syscall.UTF16PtrFromString(layerData)
+	if hr != nil {
+		return
+	}
+	var _p2 *uint16
+	_p2, hr = syscall.UTF16PtrFromString(options)
+	if hr != nil {
+		return
+	}
+	return _hcsInitializeWritableLayer(_p0, _p1, _p2)
+}
+
+func _hcsInitializeWritableLayer(writableLayerPath *uint16, layerData *uint16, options *uint16) (hr error) {
+	if hr = procHcsInitializeWritableLayer.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsInitializeWritableLayer.Addr(), 3, uintptr(unsafe.Pointer(writableLayerPath)), uintptr(unsafe.Pointer(layerData)), uintptr(unsafe.Pointer(options)))
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsAttachLayerStorageFilter(layerPath string, layerData string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, hr = syscall.UTF16PtrFromString(layerData)
+	if hr != nil {
+		return
+	}
+	return _hcsAttachLayerStorageFilter(_p0, _p1)
+}
+
+func _hcsAttachLayerStorageFilter(layerPath *uint16, layerData *uint16) (hr error) {
+	if hr = procHcsAttachLayerStorageFilter.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsAttachLayerStorageFilter.Addr(), 2, uintptr(unsafe.Pointer(layerPath)), uintptr(unsafe.Pointer(layerData)), 0)
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsDetachLayerStorageFilter(layerPath string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	return _hcsDetachLayerStorageFilter(_p0)
+}
+
+func _hcsDetachLayerStorageFilter(layerPath *uint16) (hr error) {
+	if hr = procHcsDetachLayerStorageFilter.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsDetachLayerStorageFilter.Addr(), 1, uintptr(unsafe.Pointer(layerPath)), 0, 0)
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsFormatWritableLayerVhd(handle windows.Handle) (hr error) {
+	if hr = procHcsFormatWritableLayerVhd.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsFormatWritableLayerVhd.Addr(), 1, uintptr(handle), 0, 0)
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsGetLayerVhdMountPath(vhdHandle windows.Handle, mountPath **uint16) (hr error) {
+	if hr = procHcsGetLayerVhdMountPath.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsGetLayerVhdMountPath.Addr(), 2, uintptr(vhdHandle), uintptr(unsafe.Pointer(mountPath)), 0)
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}
+
+func hcsSetupBaseOSVolume(layerPath string, volumePath string, options string) (hr error) {
+	var _p0 *uint16
+	_p0, hr = syscall.UTF16PtrFromString(layerPath)
+	if hr != nil {
+		return
+	}
+	var _p1 *uint16
+	_p1, hr = syscall.UTF16PtrFromString(volumePath)
+	if hr != nil {
+		return
+	}
+	var _p2 *uint16
+	_p2, hr = syscall.UTF16PtrFromString(options)
+	if hr != nil {
+		return
+	}
+	return _hcsSetupBaseOSVolume(_p0, _p1, _p2)
+}
+
+func _hcsSetupBaseOSVolume(layerPath *uint16, volumePath *uint16, options *uint16) (hr error) {
+	if hr = procHcsSetupBaseOSVolume.Find(); hr != nil {
+		return
+	}
+	r0, _, _ := syscall.Syscall(procHcsSetupBaseOSVolume.Addr(), 3, uintptr(unsafe.Pointer(layerPath)), uintptr(unsafe.Pointer(volumePath)), uintptr(unsafe.Pointer(options)))
+	if int32(r0) < 0 {
+		if r0&0x1fff0000 == 0x00070000 {
+			r0 &= 0xffff
+		}
+		hr = syscall.Errno(r0)
+	}
+	return
+}