pkg/chrootarchive: pass TarOptions via CLI arg

Signed-off-by: Tibor Vass <teabee89@gmail.com>

chrootarchive/archive.go

@@ -1,11 +1,14 @@
 package chrootarchive
 
 import (
+	"bytes"
+	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
 	"os"
 	"runtime"
+	"strings"
 	"syscall"
 
 	"github.com/docker/docker/pkg/archive"
@@ -22,7 +25,12 @@ func untar() {
 	if err := syscall.Chdir("/"); err != nil {
 		fatal(err)
 	}
-	if err := archive.Untar(os.Stdin, "/", nil); err != nil {
+	options := new(archive.TarOptions)
+	dec := json.NewDecoder(strings.NewReader(flag.Arg(1)))
+	if err := dec.Decode(options); err != nil {
+		fatal(err)
+	}
+	if err := archive.Untar(os.Stdin, "/", options); err != nil {
 		fatal(err)
 	}
 	os.Exit(0)
@@ -33,12 +41,18 @@ var (
 )
 
 func Untar(archive io.Reader, dest string, options *archive.TarOptions) error {
+	var buf bytes.Buffer
+	enc := json.NewEncoder(&buf)
+	if err := enc.Encode(options); err != nil {
+		return fmt.Errorf("Untar json encode: %v", err)
+	}
 	if _, err := os.Stat(dest); os.IsNotExist(err) {
 		if err := os.MkdirAll(dest, 0777); err != nil {
 			return err
 		}
 	}
-	cmd := reexec.Command("docker-untar", dest)
+
+	cmd := reexec.Command("docker-untar", dest, buf.String())
 	cmd.Stdin = archive
 	out, err := cmd.CombinedOutput()
 	if err != nil {

chrootarchive/archive_test.go

@@ -0,0 +1,39 @@
+package chrootarchive
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"testing"
+
+	"github.com/docker/docker/pkg/archive"
+)
+
+func TestChrootTarUntar(t *testing.T) {
+	tmpdir, err := ioutil.TempDir("", "docker-TestChrootTarUntar")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.RemoveAll(tmpdir)
+	src := filepath.Join(tmpdir, "src")
+	if err := os.MkdirAll(src, 0700); err != nil {
+		t.Fatal(err)
+	}
+	if err := ioutil.WriteFile(filepath.Join(src, "toto"), []byte("hello toto"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	if err := ioutil.WriteFile(filepath.Join(src, "lolo"), []byte("hello lolo"), 0644); err != nil {
+		t.Fatal(err)
+	}
+	stream, err := archive.Tar(src, archive.Uncompressed)
+	if err != nil {
+		t.Fatal(err)
+	}
+	dest := filepath.Join(tmpdir, "src")
+	if err := os.MkdirAll(dest, 0700); err != nil {
+		t.Fatal(err)
+	}
+	if err := Untar(stream, dest, &archive.TarOptions{Excludes: []string{"lolo"}}); err != nil {
+		t.Fatal(err)
+	}
+}

chrootarchive/init.go

@@ -10,6 +10,7 @@ import (
 func init() {
 	reexec.Register("docker-untar", untar)
 	reexec.Register("docker-applyLayer", applyLayer)
+	reexec.Init()
 }
 
 func fatal(err error) {