From 4d66163297403e1f4a85fa9601886eae31f551ac Mon Sep 17 00:00:00 2001
From: Vincent Batts <vbatts@hashbangbash.com>
Date: Thu, 13 Aug 2015 15:32:17 -0400
Subject: [PATCH] archive/tar: a []byte copy needed for GNU LongLink

---
 archive/tar/reader.go | 32 ++++++++++----------------------
 1 file changed, 10 insertions(+), 22 deletions(-)

diff --git a/archive/tar/reader.go b/archive/tar/reader.go
index f817956..c72e002 100644
--- a/archive/tar/reader.go
+++ b/archive/tar/reader.go
@@ -154,60 +154,48 @@ func (tr *Reader) Next() (*Header, error) {
 		}
 		return hdr, nil
 	case TypeGNULongName:
-		var b *bytes.Buffer
-		if tr.RawAccounting {
-			b = bytes.NewBuffer(tr.RawBytes())
-		}
 		// We have a GNU long name header. Its contents are the real file name.
 		realname, err := ioutil.ReadAll(tr)
 		if err != nil {
 			return nil, err
 		}
+		var buf []byte
 		if tr.RawAccounting {
-			if _, err = tr.rawBytes.Write(b.Bytes()); err != nil {
-				return nil, err
-			}
 			if _, err = tr.rawBytes.Write(realname); err != nil {
 				return nil, err
 			}
-			b.Reset()
-			b.Write(tr.RawBytes())
+			buf = make([]byte, tr.rawBytes.Len())
+			copy(buf[:], tr.RawBytes())
 		}
 		hdr, err := tr.Next()
 		// since the above call to Next() resets the buffer, we need to throw the bytes over
 		if tr.RawAccounting {
-			b.Write(tr.RawBytes())
-			if _, err = tr.rawBytes.Write(b.Bytes()); err != nil {
+			buf = append(buf, tr.RawBytes()...)
+			if _, err = tr.rawBytes.Write(buf); err != nil {
 				return nil, err
 			}
 		}
 		hdr.Name = cString(realname)
 		return hdr, err
 	case TypeGNULongLink:
-		var b *bytes.Buffer
-		if tr.RawAccounting {
-			b = bytes.NewBuffer(tr.RawBytes())
-		}
 		// We have a GNU long link header.
 		realname, err := ioutil.ReadAll(tr)
 		if err != nil {
 			return nil, err
 		}
+		var buf []byte
 		if tr.RawAccounting {
-			if _, err = tr.rawBytes.Write(b.Bytes()); err != nil {
-				return nil, err
-			}
 			if _, err = tr.rawBytes.Write(realname); err != nil {
 				return nil, err
 			}
-			b.Reset()
-			b.Write(tr.RawBytes())
+			buf = make([]byte, tr.rawBytes.Len())
+			copy(buf[:], tr.RawBytes())
 		}
 		hdr, err := tr.Next()
 		// since the above call to Next() resets the buffer, we need to throw the bytes over
 		if tr.RawAccounting {
-			b.Write(tr.RawBytes())
-			if _, err = tr.rawBytes.Write(b.Bytes()); err != nil {
+			buf = append(buf, tr.RawBytes()...)
+			if _, err = tr.rawBytes.Write(buf); err != nil {
 				return nil, err
 			}
 		}