Implements the Windows lcow differ/snapshotter responsible for managing the creation and lifetime of lcow containers on Windows. Signed-off-by: Justin Terry (VM) <juterry@microsoft.com>
		
			
				
	
	
		
			106 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			106 lines
		
	
	
		
			2.8 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
/*
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   Copyright The containerd Authors.
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   Licensed under the Apache License, Version 2.0 (the "License");
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   you may not use this file except in compliance with the License.
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   You may obtain a copy of the License at
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       http://www.apache.org/licenses/LICENSE-2.0
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   Unless required by applicable law or agreed to in writing, software
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   distributed under the License is distributed on an "AS IS" BASIS,
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   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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   See the License for the specific language governing permissions and
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   limitations under the License.
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*/
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package mount
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import (
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	"encoding/json"
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	"path/filepath"
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	"strings"
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	"github.com/Microsoft/hcsshim"
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	"github.com/pkg/errors"
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)
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var (
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	// ErrNotImplementOnWindows is returned when an action is not implemented for windows
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	ErrNotImplementOnWindows = errors.New("not implemented under windows")
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)
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// Mount to the provided target
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func (m *Mount) Mount(target string) error {
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	if m.Type != "windows-layer" {
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		return errors.Errorf("invalid windows mount type: '%s'", m.Type)
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	}
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	home, layerID := filepath.Split(m.Source)
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	parentLayerPaths, err := m.GetParentPaths()
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	if err != nil {
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		return err
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	}
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	var di = hcsshim.DriverInfo{
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		HomeDir: home,
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	}
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	if err = hcsshim.ActivateLayer(di, layerID); err != nil {
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		return errors.Wrapf(err, "failed to activate layer %s", m.Source)
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	}
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	defer func() {
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		if err != nil {
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			hcsshim.DeactivateLayer(di, layerID)
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		}
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	}()
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	if err = hcsshim.PrepareLayer(di, layerID, parentLayerPaths); err != nil {
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		return errors.Wrapf(err, "failed to prepare layer %s", m.Source)
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	}
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	return nil
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}
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// ParentLayerPathsFlag is the options flag used to represent the JSON encoded
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// list of parent layers required to use the layer
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const ParentLayerPathsFlag = "parentLayerPaths="
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// GetParentPaths of the mount
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func (m *Mount) GetParentPaths() ([]string, error) {
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	var parentLayerPaths []string
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	for _, option := range m.Options {
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		if strings.HasPrefix(option, ParentLayerPathsFlag) {
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			err := json.Unmarshal([]byte(option[len(ParentLayerPathsFlag):]), &parentLayerPaths)
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			if err != nil {
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				return nil, errors.Wrap(err, "failed to unmarshal parent layer paths from mount")
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			}
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		}
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	}
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	return parentLayerPaths, nil
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}
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// Unmount the mount at the provided path
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func Unmount(mount string, flags int) error {
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	var (
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		home, layerID = filepath.Split(mount)
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		di            = hcsshim.DriverInfo{
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			HomeDir: home,
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		}
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	)
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	if err := hcsshim.UnprepareLayer(di, layerID); err != nil {
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		return errors.Wrapf(err, "failed to unprepare layer %s", mount)
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	}
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	if err := hcsshim.DeactivateLayer(di, layerID); err != nil {
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		return errors.Wrapf(err, "failed to deactivate layer %s", mount)
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	}
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	return nil
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}
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// UnmountAll unmounts from the provided path
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func UnmountAll(mount string, flags int) error {
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	return Unmount(mount, flags)
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}
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