diff --git a/archive/tar/reader.go b/archive/tar/reader.go index 02df550..ba34ed7 100644 --- a/archive/tar/reader.go +++ b/archive/tar/reader.go @@ -138,8 +138,6 @@ func NewReader(r io.Reader) *Reader { return &Reader{r: r} } // // io.EOF is returned at the end of the input. func (tr *Reader) Next() (*Header, error) { - var p parser - var hdr *Header if tr.RawAccounting { if tr.rawBytes == nil { tr.rawBytes = bytes.NewBuffer(nil) @@ -147,114 +145,88 @@ func (tr *Reader) Next() (*Header, error) { tr.rawBytes.Reset() } } - if tr.err == nil { - tr.skipUnread() - } + if tr.err != nil { - return hdr, tr.err + return nil, tr.err } - hdr = tr.readHeader() - if hdr == nil { - return hdr, tr.err - } - // Check for PAX/GNU header. - switch hdr.Typeflag { - case TypeXHeader: - // PAX extended header - headers, err := parsePAX(tr) - if err != nil { - return nil, err - } - // We actually read the whole file, - // but this skips alignment padding - tr.skipUnread() + + var hdr *Header + var extHdrs map[string]string + + // Externally, Next iterates through the tar archive as if it is a series of + // files. Internally, the tar format often uses fake "files" to add meta + // data that describes the next file. These meta data "files" should not + // normally be visible to the outside. As such, this loop iterates through + // one or more "header files" until it finds a "normal file". +loop: + for { + tr.err = tr.skipUnread() if tr.err != nil { return nil, tr.err } + hdr = tr.readHeader() - if hdr == nil { + if tr.err != nil { return nil, tr.err } - mergePAX(hdr, headers) - - // Check for a PAX format sparse file - sp, err := tr.checkForGNUSparsePAXHeaders(hdr, headers) - if err != nil { - tr.err = err - return nil, err - } - if sp != nil { - // Sparse files do not make sense when applied to the special header - // types that never have a data section. - if isHeaderOnlyType(hdr.Typeflag) { - tr.err = ErrHeader - return nil, tr.err - } - - // Current file is a PAX format GNU sparse file. - // Set the current file reader to a sparse file reader. - tr.curr, tr.err = newSparseFileReader(tr.curr, sp, hdr.Size) + // Check for PAX/GNU special headers and files. + switch hdr.Typeflag { + case TypeXHeader: + extHdrs, tr.err = parsePAX(tr) if tr.err != nil { return nil, tr.err } - } - return hdr, nil - case TypeGNULongName: - // 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(realname); err != nil { + continue loop // This is a meta header affecting the next header + case TypeGNULongName, TypeGNULongLink: + var realname []byte + realname, tr.err = ioutil.ReadAll(tr) + if tr.err != nil { + return nil, tr.err + } + + if tr.RawAccounting { + if _, tr.err = tr.rawBytes.Write(realname); tr.err != nil { + return nil, tr.err + } + } + + // Convert GNU extensions to use PAX headers. + if extHdrs == nil { + extHdrs = make(map[string]string) + } + var p parser + switch hdr.Typeflag { + case TypeGNULongName: + extHdrs[paxPath] = p.parseString(realname) + case TypeGNULongLink: + extHdrs[paxLinkpath] = p.parseString(realname) + } + if p.err != nil { + tr.err = p.err + return nil, tr.err + } + continue loop // This is a meta header affecting the next header + default: + mergePAX(hdr, extHdrs) + + // Check for a PAX format sparse file + sp, err := tr.checkForGNUSparsePAXHeaders(hdr, extHdrs) + if err != nil { + tr.err = err return nil, err } - 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 { - buf = append(buf, tr.RawBytes()...) - if _, err = tr.rawBytes.Write(buf); err != nil { - return nil, err + if sp != nil { + // Current file is a PAX format GNU sparse file. + // Set the current file reader to a sparse file reader. + tr.curr, tr.err = newSparseFileReader(tr.curr, sp, hdr.Size) + if tr.err != nil { + return nil, tr.err + } } + break loop // This is a file, so stop } - hdr.Name = p.parseString(realname) - if p.err != nil { - return nil, p.err - } - return hdr, nil - case TypeGNULongLink: - // 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(realname); err != nil { - return nil, err - } - 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 { - buf = append(buf, tr.RawBytes()...) - if _, err = tr.rawBytes.Write(buf); err != nil { - return nil, err - } - } - hdr.Name = p.parseString(realname) - if p.err != nil { - return nil, p.err - } - return hdr, nil } - return hdr, tr.err + return hdr, nil } // checkForGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers. If they are found, then diff --git a/archive/tar/reader_test.go b/archive/tar/reader_test.go index f0dbd94..861d1a5 100644 --- a/archive/tar/reader_test.go +++ b/archive/tar/reader_test.go @@ -288,6 +288,30 @@ var untarTests = []*untarTest{ }, }, }, + { + // Matches the behavior of GNU, BSD, and STAR tar utilities. + file: "testdata/gnu-multi-hdrs.tar", + headers: []*Header{ + { + Name: "GNU2/GNU2/long-path-name", + Linkname: "GNU4/GNU4/long-linkpath-name", + ModTime: time.Unix(0, 0), + Typeflag: '2', + }, + }, + }, + { + // Matches the behavior of GNU and BSD tar utilities. + file: "testdata/pax-multi-hdrs.tar", + headers: []*Header{ + { + Name: "bar", + Linkname: "PAX4/PAX4/long-linkpath-name", + ModTime: time.Unix(0, 0), + Typeflag: '2', + }, + }, + }, { file: "testdata/neg-size.tar", err: ErrHeader, diff --git a/archive/tar/testdata/gnu-multi-hdrs.tar b/archive/tar/testdata/gnu-multi-hdrs.tar new file mode 100644 index 0000000..8bcad55 Binary files /dev/null and b/archive/tar/testdata/gnu-multi-hdrs.tar differ diff --git a/archive/tar/testdata/pax-multi-hdrs.tar b/archive/tar/testdata/pax-multi-hdrs.tar new file mode 100644 index 0000000..14bc759 Binary files /dev/null and b/archive/tar/testdata/pax-multi-hdrs.tar differ