chrootarchive: use archive untar implementation on Windows

chrootarchive/archive.go

@@ -1,15 +1,11 @@
 package chrootarchive
 
 import (
-	"errors"
 	"io"
-	"os"
-	"path/filepath"
 
 	"github.com/moby/sys/user"
 
 	"github.com/moby/go-archive"
-	"github.com/moby/go-archive/compression"
 )
 
 // NewArchiver returns a new Archiver which uses chrootarchive.Untar
@@ -51,41 +47,6 @@ func UntarUncompressed(tarArchive io.Reader, dest string, options *archive.TarOp
 	return untarHandler(tarArchive, dest, options, false, dest)
 }
 
-// Handler for teasing out the automatic decompression
-func untarHandler(tarArchive io.Reader, dest string, options *archive.TarOptions, decompress bool, root string) error {
-	if tarArchive == nil {
-		return errors.New("empty archive")
-	}
-	if options == nil {
-		options = &archive.TarOptions{}
-	}
-
-	// If dest is inside a root then directory is created within chroot by extractor.
-	// This case is only currently used by cp.
-	if dest == root {
-		uid, gid := options.IDMap.RootPair()
-
-		dest = filepath.Clean(dest)
-		if _, err := os.Stat(dest); os.IsNotExist(err) {
-			if err := user.MkdirAllAndChown(dest, 0o755, uid, gid, user.WithOnlyNew); err != nil {
-				return err
-			}
-		}
-	}
-
-	r := io.NopCloser(tarArchive)
-	if decompress {
-		decompressedArchive, err := compression.DecompressStream(tarArchive)
-		if err != nil {
-			return err
-		}
-		defer decompressedArchive.Close()
-		r = decompressedArchive
-	}
-
-	return invokeUnpack(r, dest, options, root)
-}
-
 // Tar tars the requested path while chrooted to the specified root.
 func Tar(srcPath string, options *archive.TarOptions, root string) (io.ReadCloser, error) {
 	if options == nil {

chrootarchive/archive_unix.go

@@ -5,12 +5,51 @@ package chrootarchive
 import (
 	"errors"
 	"io"
+	"os"
 	"path/filepath"
 	"strings"
 
 	"github.com/moby/go-archive"
+	"github.com/moby/go-archive/compression"
+	"github.com/moby/sys/user"
 )
 
+// Handler for teasing out the automatic decompression
+func untarHandler(tarArchive io.Reader, dest string, options *archive.TarOptions, decompress bool, root string) error {
+	if tarArchive == nil {
+		return errors.New("empty archive")
+	}
+	if options == nil {
+		options = &archive.TarOptions{}
+	}
+
+	// Create dest here only if it is the root itself; paths below the root are
+	// created by the extractor after entering the chroot.
+	// This case is only currently used by cp.
+	if dest == root {
+		uid, gid := options.IDMap.RootPair()
+
+		dest = filepath.Clean(dest)
+		if _, err := os.Stat(dest); os.IsNotExist(err) {
+			if err := user.MkdirAllAndChown(dest, 0o755, uid, gid, user.WithOnlyNew); err != nil {
+				return err
+			}
+		}
+	}
+
+	r := io.NopCloser(tarArchive)
+	if decompress {
+		decompressedArchive, err := compression.DecompressStream(tarArchive)
+		if err != nil {
+			return err
+		}
+		defer decompressedArchive.Close()
+		r = decompressedArchive
+	}
+
+	return invokeUnpack(r, dest, options, root)
+}
+
 func invokeUnpack(decompressedArchive io.Reader, dest string, options *archive.TarOptions, root string) error {
 	relDest, err := resolvePathInChroot(root, dest)
 	if err != nil {

chrootarchive/archive_windows.go

@@ -1,7 +1,10 @@
 package chrootarchive
 
 import (
+	"errors"
 	"io"
+	"os"
+	"path/filepath"
 	"strings"
 
 	"github.com/moby/go-archive"
@@ -25,14 +28,34 @@ func addLongPathPrefix(srcPath string) string {
 	return longPathPrefix + srcPath
 }
 
-func invokeUnpack(decompressedArchive io.ReadCloser, dest string, options *archive.TarOptions, root string) error {
+// Handler for teasing out the automatic decompression
+func untarHandler(tarArchive io.Reader, dest string, options *archive.TarOptions, decompress bool, root string) error {
+	if tarArchive == nil {
+		return errors.New("empty archive")
+	}
+
+	// Create dest here only if it is the root itself; paths below the root are
+	// created by the extractor after entering the chroot.
+	// This case is only currently used by cp.
+	if dest == root {
+		dest = filepath.Clean(dest)
+		if _, err := os.Stat(dest); os.IsNotExist(err) {
+			if err := os.MkdirAll(dest, 0); err != nil {
+				return err
+			}
+		}
+	}
+
 	// Windows is different to Linux here because Windows does not support
 	// chroot. Hence there is no point sandboxing a chrooted process to
 	// do the unpack. We call inline instead within the daemon process.
-	return archive.Unpack(decompressedArchive, addLongPathPrefix(dest), options)
+	if decompress {
+		return archive.Untar(tarArchive, addLongPathPrefix(dest), options)
+	}
+	return archive.UntarUncompressed(tarArchive, addLongPathPrefix(dest), options)
 }
 
-func invokePack(srcPath string, options *archive.TarOptions, root string) (io.ReadCloser, error) {
+func invokePack(srcPath string, options *archive.TarOptions, _ string) (io.ReadCloser, error) {
 	// Windows is different to Linux here because Windows does not support
 	// chroot. Hence there is no point sandboxing a chrooted process to
 	// do the pack. We call inline instead within the daemon process.