archive: add ChownOpts support to TarWithOptions

Signed-off-by: Sébastien HOUZÉ <cto@verylastroom.com>

pkg/archive/archive.go

@@ -382,6 +382,7 @@ type tarAppender struct {
 	// for hardlink mapping
 	SeenFiles  map[uint64]string
 	IDMappings *idtools.IDMappings
+	ChownOpts  *idtools.IDPair
 
 	// For packing and unpacking whiteout files in the
 	// non standard format. The whiteout files defined
@@ -390,12 +391,13 @@ type tarAppender struct {
 	WhiteoutConverter tarWhiteoutConverter
 }
 
-func newTarAppender(idMapping *idtools.IDMappings, writer io.Writer) *tarAppender {
+func newTarAppender(idMapping *idtools.IDMappings, writer io.Writer, chownOpts *idtools.IDPair) *tarAppender {
 	return &tarAppender{
 		SeenFiles:  make(map[uint64]string),
 		TarWriter:  tar.NewWriter(writer),
 		Buffer:     pools.BufioWriter32KPool.Get(nil),
 		IDMappings: idMapping,
+		ChownOpts:  chownOpts,
 	}
 }
 
@@ -470,6 +472,12 @@ func (ta *tarAppender) addTarFile(path, name string) error {
 		}
 	}
 
+	// explicitly override with ChownOpts
+	if ta.ChownOpts != nil {
+		hdr.Uid = ta.ChownOpts.UID
+		hdr.Gid = ta.ChownOpts.GID
+	}
+
 	if ta.WhiteoutConverter != nil {
 		wo, err := ta.WhiteoutConverter.ConvertWrite(hdr, path, fi)
 		if err != nil {
@@ -692,6 +700,7 @@ func TarWithOptions(srcPath string, options *TarOptions) (io.ReadCloser, error)
 		ta := newTarAppender(
 			idtools.NewIDMappingsFromMaps(options.UIDMaps, options.GIDMaps),
 			compressWriter,
+			options.ChownOpts,
 		)
 		ta.WhiteoutConverter = getWhiteoutConverter(options.WhiteoutFormat)
 

pkg/archive/archive_test.go

@@ -14,6 +14,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/docker/docker/pkg/idtools"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -724,6 +725,57 @@ func TestTarUntar(t *testing.T) {
 	}
 }
 
+func TestTarWithOptionsChownOptsAlwaysOverridesIdPair(t *testing.T) {
+	origin, err := ioutil.TempDir("", "docker-test-tar-chown-opt")
+	require.NoError(t, err)
+
+	defer os.RemoveAll(origin)
+	filePath := filepath.Join(origin, "1")
+	err = ioutil.WriteFile(filePath, []byte("hello world"), 0700)
+	require.NoError(t, err)
+
+	idMaps := []idtools.IDMap{
+		0: {
+			ContainerID: 0,
+			HostID:      0,
+			Size:        65536,
+		},
+		1: {
+			ContainerID: 0,
+			HostID:      100000,
+			Size:        65536,
+		},
+	}
+
+	cases := []struct {
+		opts        *TarOptions
+		expectedUID int
+		expectedGID int
+	}{
+		{&TarOptions{ChownOpts: &idtools.IDPair{UID: 1337, GID: 42}}, 1337, 42},
+		{&TarOptions{ChownOpts: &idtools.IDPair{UID: 100001, GID: 100001}, UIDMaps: idMaps, GIDMaps: idMaps}, 100001, 100001},
+		{&TarOptions{ChownOpts: &idtools.IDPair{UID: 0, GID: 0}, NoLchown: false}, 0, 0},
+		{&TarOptions{ChownOpts: &idtools.IDPair{UID: 1, GID: 1}, NoLchown: true}, 1, 1},
+		{&TarOptions{ChownOpts: &idtools.IDPair{UID: 1000, GID: 1000}, NoLchown: true}, 1000, 1000},
+	}
+	for _, testCase := range cases {
+		reader, err := TarWithOptions(filePath, testCase.opts)
+		require.NoError(t, err)
+		tr := tar.NewReader(reader)
+		defer reader.Close()
+		for {
+			hdr, err := tr.Next()
+			if err == io.EOF {
+				// end of tar archive
+				break
+			}
+			require.NoError(t, err)
+			assert.Equal(t, hdr.Uid, testCase.expectedUID, "Uid equals expected value")
+			assert.Equal(t, hdr.Gid, testCase.expectedGID, "Gid equals expected value")
+		}
+	}
+}
+
 func TestTarWithOptions(t *testing.T) {
 	// TODO Windows: Figure out how to fix this test.
 	if runtime.GOOS == "windows" {

pkg/archive/changes.go

@@ -394,7 +394,7 @@ func ChangesSize(newDir string, changes []Change) int64 {
 func ExportChanges(dir string, changes []Change, uidMaps, gidMaps []idtools.IDMap) (io.ReadCloser, error) {
 	reader, writer := io.Pipe()
 	go func() {
-		ta := newTarAppender(idtools.NewIDMappingsFromMaps(uidMaps, gidMaps), writer)
+		ta := newTarAppender(idtools.NewIDMappingsFromMaps(uidMaps, gidMaps), writer, nil)
 
 		// this buffer is needed for the duration of this piped stream
 		defer pools.BufioWriter32KPool.Put(ta.Buffer)