pkg/archive: adjust chmod bits on windows

This change modifies the chmod bits of build context archives built on
windows to preserve the execute bit and remove the r/w bits from
grp/others.

Also adjusted integ-cli tests to verify permissions based on the platform
the tests are running.

Fixes #11047.

Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>

archive/archive.go

@@ -204,6 +204,7 @@ func (ta *tarAppender) addTarFile(path, name string) error {
 	if err != nil {
 		return err
 	}
+	hdr.Mode = int64(chmodTarEntry(os.FileMode(hdr.Mode)))
 
 	name, err = canonicalTarName(name, fi.IsDir())
 	if err != nil {
@@ -696,6 +697,8 @@ func (archiver *Archiver) CopyFileWithTar(src, dst string) (err error) {
 			return err
 		}
 		hdr.Name = filepath.Base(dst)
+		hdr.Mode = int64(chmodTarEntry(os.FileMode(hdr.Mode)))
+
 		tw := tar.NewWriter(w)
 		defer tw.Close()
 		if err := tw.WriteHeader(hdr); err != nil {

archive/archive_unix.go

@@ -4,6 +4,7 @@ package archive
 
 import (
 	"errors"
+	"os"
 	"syscall"
 
 	"github.com/docker/docker/vendor/src/code.google.com/p/go/src/pkg/archive/tar"
@@ -16,6 +17,13 @@ func CanonicalTarNameForPath(p string) (string, error) {
 	return p, nil // already unix-style
 }
 
+// chmodTarEntry is used to adjust the file permissions used in tar header based
+// on the platform the archival is done.
+
+func chmodTarEntry(perm os.FileMode) os.FileMode {
+	return perm // noop for unix as golang APIs provide perm bits correctly
+}
+
 func setHeaderForSpecialDevice(hdr *tar.Header, ta *tarAppender, name string, stat interface{}) (nlink uint32, inode uint64, err error) {
 	s, ok := stat.(*syscall.Stat_t)
 

archive/archive_unix_test.go

@@ -3,6 +3,7 @@
 package archive
 
 import (
+	"os"
 	"testing"
 )
 
@@ -40,3 +41,20 @@ func TestCanonicalTarName(t *testing.T) {
 		}
 	}
 }
+
+func TestChmodTarEntry(t *testing.T) {
+	cases := []struct {
+		in, expected os.FileMode
+	}{
+		{0000, 0000},
+		{0777, 0777},
+		{0644, 0644},
+		{0755, 0755},
+		{0444, 0444},
+	}
+	for _, v := range cases {
+		if out := chmodTarEntry(v.in); out != v.expected {
+			t.Fatalf("wrong chmod. expected:%v got:%v", v.expected, out)
+		}
+	}
+}

archive/archive_windows.go

@@ -4,6 +4,7 @@ package archive
 
 import (
 	"fmt"
+	"os"
 	"strings"
 
 	"github.com/docker/docker/vendor/src/code.google.com/p/go/src/pkg/archive/tar"
@@ -23,6 +24,17 @@ func CanonicalTarNameForPath(p string) (string, error) {
 	return strings.Replace(p, "\\", "/", -1), nil
 }
 
+// chmodTarEntry is used to adjust the file permissions used in tar header based
+// on the platform the archival is done.
+func chmodTarEntry(perm os.FileMode) os.FileMode {
+	// Clear r/w on grp/others: no precise equivalen of group/others on NTFS.
+	perm &= 0711
+	// Add the x bit: make everything +x from windows
+	perm |= 0100
+
+	return perm
+}
+
 func setHeaderForSpecialDevice(hdr *tar.Header, ta *tarAppender, name string, stat interface{}) (nlink uint32, inode uint64, err error) {
 	// do nothing. no notion of Rdev, Inode, Nlink in stat on Windows
 	return

archive/archive_windows_test.go

@@ -3,6 +3,7 @@
 package archive
 
 import (
+	"os"
 	"testing"
 )
 
@@ -46,3 +47,20 @@ func TestCanonicalTarName(t *testing.T) {
 		}
 	}
 }
+
+func TestChmodTarEntry(t *testing.T) {
+	cases := []struct {
+		in, expected os.FileMode
+	}{
+		{0000, 0100},
+		{0777, 0711},
+		{0644, 0700},
+		{0755, 0711},
+		{0444, 0500},
+	}
+	for _, v := range cases {
+		if out := chmodTarEntry(v.in); out != v.expected {
+			t.Fatalf("wrong chmod. expected:%v got:%v", v.expected, out)
+		}
+	}
+}