From 52ccdf3510a1c2920a4398ca032ead3c57657d51 Mon Sep 17 00:00:00 2001
From: David Symonds <dsymonds@golang.org>
Date: Mon, 6 Jul 2009 22:59:31 -0700
Subject: [PATCH] Add support for v7 tar.

R=rsc
APPROVED=rsc
DELTA=32  (26 added, 4 deleted, 2 changed)
OCL=31172
CL=31242
---
 src/pkg/archive/tar/testdata/v7.tar | Bin 0 -> 3072 bytes
 src/pkg/archive/tar/untar.go        |  10 ++++------
 src/pkg/archive/tar/untar_test.go   |  23 +++++++++++++++++++++++
 3 files changed, 27 insertions(+), 6 deletions(-)
 create mode 100644 src/pkg/archive/tar/testdata/v7.tar

diff --git a/src/pkg/archive/tar/testdata/v7.tar b/src/pkg/archive/tar/testdata/v7.tar
new file mode 100644
index 0000000000000000000000000000000000000000..dd33f92ffad5343d19a36f20814c85e935b08008
GIT binary patch
literal 3072
zcmeH{Jqp7x423oK6gffAPpllFLrxJwDFp`)_R!<kg0y2dg%<QSdw9?K@KfE_oX7TT
z;3w?T2?3cjAps(hQa^u`fQVU8SQ7X9Sy^H5dy#|lG0S@>hXfbP<&j%;aSqdeAW*IU
x?7IN08ejWQV*R(BK*E#tf5sI3KjZ&gOS$LUxRw2KMqFeBfglhBg20aucma2<CEox5

literal 0
HcmV?d00001

diff --git a/src/pkg/archive/tar/untar.go b/src/pkg/archive/tar/untar.go
index e662971a4f..3ebfc5e562 100644
--- a/src/pkg/archive/tar/untar.go
+++ b/src/pkg/archive/tar/untar.go
@@ -4,7 +4,7 @@
 
 // The tar package implements access to tar archives.
 // It aims to cover most of the variations, including those produced
-// by GNU and BSD tars (not yet started).
+// by GNU and BSD tars.
 //
 // References:
 //   http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5
@@ -12,8 +12,7 @@
 package tar
 
 // TODO(dsymonds):
-// - Make it seekable.
-// - Extensions.
+//   - pax extensions
 
 import (
 	"bufio";
@@ -211,9 +210,6 @@ func (tr *Reader) readHeader() *Header {
 	hdr := new(Header);
 	s := slicer(header);
 
-	// TODO(dsymonds): The format of the header depends on the value of magic (hdr[257:262]),
-	// so use that value to do the correct parsing below.
-
 	hdr.Name = cString(s.next(100));
 	hdr.Mode = tr.octal(s.next(8));
 	hdr.Uid = tr.octal(s.next(8));
@@ -225,6 +221,8 @@ func (tr *Reader) readHeader() *Header {
 	hdr.Linkname = cString(s.next(100));
 
 	// The remainder of the header depends on the value of magic.
+	// The original (v7) version of tar had no explicit magic field,
+	// so its magic bytes, like the rest of the block, are NULs.
 	magic := string(s.next(8));  // contains version field as well.
 	var format string;
 	switch magic {
diff --git a/src/pkg/archive/tar/untar_test.go b/src/pkg/archive/tar/untar_test.go
index 11f7735f12..9a42c9c926 100644
--- a/src/pkg/archive/tar/untar_test.go
+++ b/src/pkg/archive/tar/untar_test.go
@@ -79,6 +79,29 @@ var untarTests = []*untarTest{
 			},
 		},
 	},
+	&untarTest{
+		file: "testdata/v7.tar",
+		headers: []*Header{
+			&Header{
+				Name: "small.txt",
+				Mode: 0640,
+				Uid: 73025,
+				Gid: 5000,
+				Size: 5,
+				Mtime: 1246508266,
+				Typeflag: '\x00',
+			},
+			&Header{
+				Name: "small2.txt",
+				Mode: 0640,
+				Uid: 73025,
+				Gid: 5000,
+				Size: 11,
+				Mtime: 1245217492,
+				Typeflag: '\x00',
+			},
+		},
+	},
 };
 
 func TestAll(t *testing.T) {