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package wclayer
import (
"io/ioutil"
"os"
"path/filepath"
"github.com/Microsoft/go-winio"
"github.com/Microsoft/hcsshim/internal/hcserror"
"github.com/Microsoft/hcsshim/internal/safefile"
"github.com/sirupsen/logrus"
)
// ImportLayer will take the contents of the folder at importFolderPath and import
// that into a layer with the id layerId. Note that in order to correctly populate
// the layer and interperet the transport format, all parent layers must already
// be present on the system at the paths provided in parentLayerPaths.
func ImportLayer(path string, importFolderPath string, parentLayerPaths []string) error {
title := "hcsshim::ImportLayer "
logrus.Debugf(title+"path %s folder %s", path, importFolderPath)
// Generate layer descriptors
layers, err := layerPathsToDescriptors(parentLayerPaths)
if err != nil {
return err
}
err = importLayer(&stdDriverInfo, path, importFolderPath, layers)
if err != nil {
err = hcserror.Errorf(err, title, "path=%s folder=%s", path, importFolderPath)
logrus.Error(err)
return err
}
logrus.Debugf(title+"succeeded path=%s folder=%s", path, importFolderPath)
return nil
}
// LayerWriter is an interface that supports writing a new container image layer.
type LayerWriter interface {
// Add adds a file to the layer with given metadata.
Add(name string, fileInfo *winio.FileBasicInfo) error
// AddLink adds a hard link to the layer. The target must already have been added.
AddLink(name string, target string) error
// Remove removes a file that was present in a parent layer from the layer.
Remove(name string) error
// Write writes data to the current file. The data must be in the format of a Win32
// backup stream.
Write(b []byte) (int, error)
// Close finishes the layer writing process and releases any resources.
Close() error
}
type legacyLayerWriterWrapper struct {
*legacyLayerWriter
path string
parentLayerPaths []string
}
func (r *legacyLayerWriterWrapper) Close() error {
defer os.RemoveAll(r.root.Name())
defer r.legacyLayerWriter.CloseRoots()
err := r.legacyLayerWriter.Close()
if err != nil {
return err
}
if err = ImportLayer(r.destRoot.Name(), r.path, r.parentLayerPaths); err != nil {
return err
}
for _, name := range r.Tombstones {
if err = safefile.RemoveRelative(name, r.destRoot); err != nil && !os.IsNotExist(err) {
return err
}
}
// Add any hard links that were collected.
for _, lnk := range r.PendingLinks {
if err = safefile.RemoveRelative(lnk.Path, r.destRoot); err != nil && !os.IsNotExist(err) {
return err
}
if err = safefile.LinkRelative(lnk.Target, lnk.TargetRoot, lnk.Path, r.destRoot); err != nil {
return err
}
}
// Prepare the utility VM for use if one is present in the layer.
if r.HasUtilityVM {
err := safefile.EnsureNotReparsePointRelative("UtilityVM", r.destRoot)
if err != nil {
return err
}
err = ProcessUtilityVMImage(filepath.Join(r.destRoot.Name(), "UtilityVM"))
if err != nil {
return err
}
}
return nil
}
// NewLayerWriter returns a new layer writer for creating a layer on disk.
// The caller must have taken the SeBackupPrivilege and SeRestorePrivilege privileges
// to call this and any methods on the resulting LayerWriter.
func NewLayerWriter(path string, parentLayerPaths []string) (LayerWriter, error) {
if len(parentLayerPaths) == 0 {
// This is a base layer. It gets imported differently.
f, err := safefile.OpenRoot(path)
if err != nil {
return nil, err
}
return &baseLayerWriter{
root: f,
}, nil
}
importPath, err := ioutil.TempDir("", "hcs")
if err != nil {
return nil, err
}
w, err := newLegacyLayerWriter(importPath, parentLayerPaths, path)
if err != nil {
return nil, err
}
return &legacyLayerWriterWrapper{
legacyLayerWriter: w,
path: importPath,
parentLayerPaths: parentLayerPaths,
}, nil
}
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