Windows: Undo 908db518 for Windows daemon

Signed-off-by: John Howard <jhoward@microsoft.com>

chrootarchive/archive.go

@@ -30,10 +30,16 @@ func untar() {
 
 	var options *archive.TarOptions
 
+	if runtime.GOOS != "windows" {
 		//read the options from the pipe "ExtraFiles"
 		if err := json.NewDecoder(os.NewFile(3, "options")).Decode(&options); err != nil {
 			fatal(err)
 		}
+	} else {
+		if err := json.Unmarshal([]byte(os.Getenv("OPT")), &options); err != nil {
+			fatal(err)
+		}
+	}
 
 	if err := chroot(flag.Arg(0)); err != nil {
 		fatal(err)
@@ -68,19 +74,41 @@ func Untar(tarArchive io.Reader, dest string, options *archive.TarOptions) error
 	if err != nil {
 		return err
 	}
+
+	var data []byte
+	var r, w *os.File
 	defer decompressedArchive.Close()
 
+	if runtime.GOOS != "windows" {
 		// We can't pass a potentially large exclude list directly via cmd line
 		// because we easily overrun the kernel's max argument/environment size
 		// when the full image list is passed (e.g. when this is used by
 		// `docker load`). We will marshall the options via a pipe to the
 		// child
-	r, w, err := os.Pipe()
+
+		// This solution won't work on Windows as it will fail in golang
+		// exec_windows.go as at the lowest layer because attr.Files > 3
+		r, w, err = os.Pipe()
 		if err != nil {
 			return fmt.Errorf("Untar pipe failure: %v", err)
 		}
+	} else {
+		// We can't pass the exclude list directly via cmd line
+		// because we easily overrun the shell max argument list length
+		// when the full image list is passed (e.g. when this is used
+		// by `docker load`). Instead we will add the JSON marshalled
+		// and placed in the env, which has significantly larger
+		// max size
+		data, err = json.Marshal(options)
+		if err != nil {
+			return fmt.Errorf("Untar json encode: %v", err)
+		}
+	}
+
 	cmd := reexec.Command("docker-untar", dest)
 	cmd.Stdin = decompressedArchive
+
+	if runtime.GOOS != "windows" {
 		cmd.ExtraFiles = append(cmd.ExtraFiles, r)
 		output := bytes.NewBuffer(nil)
 		cmd.Stdout = output
@@ -99,6 +127,15 @@ func Untar(tarArchive io.Reader, dest string, options *archive.TarOptions) error
 			return fmt.Errorf("Untar re-exec error: %v: output: %s", err, output)
 		}
 		return nil
+	} else {
+		cmd.Env = append(cmd.Env, fmt.Sprintf("OPT=%s", data))
+		out, err := cmd.CombinedOutput()
+		if err != nil {
+			return fmt.Errorf("Untar %s %s", err, out)
+		}
+		return nil
+	}
+
 }
 
 func TarUntar(src, dst string) error {