# HG changeset patch

# User Alexander Larsson <alexander.larsson@gmail.com>

# Date 1392282510 -39600

# Node ID a15f344a9efa35ef168c8feaa92a15a1cdc93db5

# Parent  1a32fe60e0798d82bbff6c945001c7f0ba8de5ea

archive/tar: support extended attributes

This adds support for archives with the SCHILY.xattr field in the

pax header. This is what gnu tar and star generate.

Fixes issue 7154.

LGTM=dsymonds

R=golang-codereviews, gobot, dsymonds

CC=golang-codereviews

https://codereview.appspot.com/54570043

Committer: David Symonds <dsymonds@golang.org>

diff -r 1a32fe60e079 -r a15f344a9efa src/pkg/archive/tar/common.go

--- a/src/pkg/archive/tar/common.go	Thu Feb 13 03:09:03 2014 -0500

+++ b/src/pkg/archive/tar/common.go	Thu Feb 13 20:08:30 2014 +1100

@@ -57,6 +57,7 @@

 	Devminor   int64     // minor number of character or block device

 	AccessTime time.Time // access time

 	ChangeTime time.Time // status change time

+	Xattrs     map[string]string

 }

 // File name constants from the tar spec.

@@ -189,6 +190,7 @@

 	paxSize     = "size"

 	paxUid      = "uid"

 	paxUname    = "uname"

+	paxXattr    = "SCHILY.xattr."

 	paxNone     = ""

 )

diff -r 1a32fe60e079 -r a15f344a9efa src/pkg/archive/tar/reader.go

--- a/src/pkg/archive/tar/reader.go	Thu Feb 13 03:09:03 2014 -0500

+++ b/src/pkg/archive/tar/reader.go	Thu Feb 13 20:08:30 2014 +1100

@@ -139,8 +139,14 @@

 				return err

 			}

 			hdr.Size = int64(size)

+		default:

+			if strings.HasPrefix(k, paxXattr) {

+				if hdr.Xattrs == nil {

+					hdr.Xattrs = make(map[string]string)

+				}

+				hdr.Xattrs[k[len(paxXattr):]] = v

+			}

 		}

-

 	}

 	return nil

 }

diff -r 1a32fe60e079 -r a15f344a9efa src/pkg/archive/tar/reader_test.go

--- a/src/pkg/archive/tar/reader_test.go	Thu Feb 13 03:09:03 2014 -0500

+++ b/src/pkg/archive/tar/reader_test.go	Thu Feb 13 20:08:30 2014 +1100

@@ -161,6 +161,46 @@

 			},

 		},

 	},

+	{

+		file: "testdata/xattrs.tar",

+		headers: []*Header{

+			{

+				Name:       "small.txt",

+				Mode:       0644,

+				Uid:        1000,

+				Gid:        10,

+				Size:       5,

+				ModTime:    time.Unix(1386065770, 448252320),

+				Typeflag:   '0',

+				Uname:      "alex",

+				Gname:      "wheel",

+				AccessTime: time.Unix(1389782991, 419875220),

+				ChangeTime: time.Unix(1389782956, 794414986),

+				Xattrs: map[string]string{

+					"user.key":  "value",

+					"user.key2": "value2",

+					// Interestingly, selinux encodes the terminating null inside the xattr

+					"security.selinux": "unconfined_u:object_r:default_t:s0\x00",

+				},

+			},

+			{

+				Name:       "small2.txt",

+				Mode:       0644,

+				Uid:        1000,

+				Gid:        10,

+				Size:       11,

+				ModTime:    time.Unix(1386065770, 449252304),

+				Typeflag:   '0',

+				Uname:      "alex",

+				Gname:      "wheel",

+				AccessTime: time.Unix(1389782991, 419875220),

+				ChangeTime: time.Unix(1386065770, 449252304),

+				Xattrs: map[string]string{

+					"security.selinux": "unconfined_u:object_r:default_t:s0\x00",

+				},

+			},

+		},

+	},

 }

 func TestReader(t *testing.T) {

@@ -180,7 +220,7 @@

 				f.Close()

 				continue testLoop

 			}

-			if *hdr != *header {

+			if !reflect.DeepEqual(*hdr, *header) {

 				t.Errorf("test %d, entry %d: Incorrect header:\nhave %+v\nwant %+v",

 					i, j, *hdr, *header)

 			}

@@ -253,7 +293,7 @@

 		}

 		// check the header

-		if *hdr != *headers[nread] {

+		if !reflect.DeepEqual(*hdr, *headers[nread]) {

 			t.Errorf("Incorrect header:\nhave %+v\nwant %+v",

 				*hdr, headers[nread])

 		}

diff -r 1a32fe60e079 -r a15f344a9efa src/pkg/archive/tar/writer.go

--- a/src/pkg/archive/tar/writer.go	Thu Feb 13 03:09:03 2014 -0500

+++ b/src/pkg/archive/tar/writer.go	Thu Feb 13 20:08:30 2014 +1100

@@ -236,6 +236,12 @@

 		return tw.err

 	}

+	if allowPax {

+		for k, v := range hdr.Xattrs {

+			paxHeaders[paxXattr+k] = v

+		}

+	}

+

 	if len(paxHeaders) > 0 {

 		if !allowPax {

 			return errInvalidHeader

diff -r 1a32fe60e079 -r a15f344a9efa src/pkg/archive/tar/writer_test.go

--- a/src/pkg/archive/tar/writer_test.go	Thu Feb 13 03:09:03 2014 -0500

+++ b/src/pkg/archive/tar/writer_test.go	Thu Feb 13 20:08:30 2014 +1100

@@ -10,6 +10,7 @@

 	"io"

 	"io/ioutil"

 	"os"

+	"reflect"

 	"strings"

 	"testing"

 	"testing/iotest"

@@ -338,6 +339,45 @@

 	}

 }

+func TestPaxXattrs(t *testing.T) {

+	xattrs := map[string]string{

+		"user.key": "value",

+	}

+

+	// Create an archive with an xattr

+	fileinfo, err := os.Stat("testdata/small.txt")

+	if err != nil {

+		t.Fatal(err)

+	}

+	hdr, err := FileInfoHeader(fileinfo, "")

+	if err != nil {

+		t.Fatalf("os.Stat: %v", err)

+	}

+	contents := "Kilts"

+	hdr.Xattrs = xattrs

+	var buf bytes.Buffer

+	writer := NewWriter(&buf)

+	if err := writer.WriteHeader(hdr); err != nil {

+		t.Fatal(err)

+	}

+	if _, err = writer.Write([]byte(contents)); err != nil {

+		t.Fatal(err)

+	}

+	if err := writer.Close(); err != nil {

+		t.Fatal(err)

+	}

+	// Test that we can get the xattrs back out of the archive.

+	reader := NewReader(&buf)

+	hdr, err = reader.Next()

+	if err != nil {

+		t.Fatal(err)

+	}

+	if !reflect.DeepEqual(hdr.Xattrs, xattrs) {

+		t.Fatalf("xattrs did not survive round trip: got %+v, want %+v",

+			hdr.Xattrs, xattrs)

+	}

+}

+

 func TestPAXHeader(t *testing.T) {

 	medName := strings.Repeat("CD", 50)

 	longName := strings.Repeat("AB", 100)