.travis.yml

@@ -1,17 +1,17 @@
 language: go
 go:
   - tip
-  - 1.x
+  - 1.5.1
-  - 1.8.x
+  - 1.4.3
-  - 1.7.x
+  - 1.3.3
-  - 1.6.x
+  - 1.2.2
-  - 1.5.x
 
 # let us have pretty, fast Docker-based Travis workers!
 sudo: false
 
 install:
   - go get -d ./...
+  - go get golang.org/x/tools/cmd/vet
 
 script:
   - go test -v ./...

LICENSE

@@ -1,28 +1,19 @@
 Copyright (c) 2015 Vincent Batts, Raleigh, NC, USA
 
-All rights reserved.
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
 
-Redistribution and use in source and binary forms, with or without
+The above copyright notice and this permission notice shall be included in
-modification, are permitted provided that the following conditions are met:
+all copies or substantial portions of the Software.
 
-1. Redistributions of source code must retain the above copyright notice, this
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-list of conditions and the following disclaimer.
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-2. Redistributions in binary form must reproduce the above copyright notice,
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-this list of conditions and the following disclaimer in the documentation
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-and/or other materials provided with the distribution.
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-
+THE SOFTWARE.
-3. Neither the name of the copyright holder nor the names of its contributors
-may be used to endorse or promote products derived from this software without
-specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
-ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
-WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

README.md

@@ -1,7 +1,6 @@
 # tar-split
 
 [![Build Status](https://travis-ci.org/vbatts/tar-split.svg?branch=master)](https://travis-ci.org/vbatts/tar-split)
-[![Go Report Card](https://goreportcard.com/badge/github.com/vbatts/tar-split)](https://goreportcard.com/report/github.com/vbatts/tar-split)
 
 Pristinely disassembling a tar archive, and stashing needed raw bytes and offsets to reassemble a validating original archive.
 
@@ -26,23 +25,6 @@ go get github.com/vbatts/tar-split/cmd/tar-split
 For cli usage, see its [README.md](cmd/tar-split/README.md).
 For the library see the [docs](#docs)
 
-## Demo
-
-### Basic disassembly and assembly
-
-This demonstrates the `tar-split` command and how to assemble a tar archive from the `tar-data.json.gz`
-
-
-![basic cmd demo thumbnail](https://i.ytimg.com/vi/vh5wyjIOBtc/2.jpg?time=1445027151805)
-[youtube video of basic command demo](https://youtu.be/vh5wyjIOBtc)
-
-### Docker layer preservation
-
-This demonstrates the tar-split integration for docker-1.8. Providing consistent tar archives for the image layer content.
-
-![docker tar-split demo](https://i.ytimg.com/vi_webp/vh5wyjIOBtc/default.webp)
-[youtube vide of docker layer checksums](https://youtu.be/tV_Dia8E8xw)
-
 ## Caveat
 
 Eventually this should detect TARs that this is not possible with.
@@ -67,7 +49,7 @@ Do not break the API of stdlib `archive/tar` in our fork (ideally find an upstre
 
 ## Std Version
 
-The version of golang stdlib `archive/tar` is from go1.6
+The version of golang stdlib `archive/tar` is from go1.4.1, and their master branch around [a9dddb53f](https://github.com/golang/go/tree/a9dddb53f).
 It is minimally extended to expose the raw bytes of the TAR, rather than just the marshalled headers and file stream.
 
 

archive/tar/common.go

@@ -327,14 +327,3 @@ func toASCII(s string) string {
 	}
 	return buf.String()
 }
-
-// isHeaderOnlyType checks if the given type flag is of the type that has no
-// data section even if a size is specified.
-func isHeaderOnlyType(flag byte) bool {
-	switch flag {
-	case TypeLink, TypeSymlink, TypeChar, TypeBlock, TypeDir, TypeFifo:
-		return true
-	default:
-		return false
-	}
-}

archive/tar/example_test.go

@@ -26,7 +26,7 @@ func Example() {
 	}{
 		{"readme.txt", "This archive contains some text files."},
 		{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
-		{"todo.txt", "Get animal handling license."},
+		{"todo.txt", "Get animal handling licence."},
 	}
 	for _, file := range files {
 		hdr := &tar.Header{
@@ -76,5 +76,5 @@ func Example() {
 	// Geoffrey
 	// Gonzo
 	// Contents of todo.txt:
-	// Get animal handling license.
+	// Get animal handling licence.
 }

archive/tar/reader.go

@@ -12,7 +12,6 @@ import (
 	"errors"
 	"io"
 	"io/ioutil"
-	"math"
 	"os"
 	"strconv"
 	"strings"
@@ -40,10 +39,6 @@ type Reader struct {
 	rawBytes      *bytes.Buffer // last raw bits
 }
 
-type parser struct {
-	err error // Last error seen
-}
-
 // RawBytes accesses the raw bytes of the archive, apart from the file payload itself.
 // This includes the header and padding.
 //
@@ -75,36 +70,12 @@ type regFileReader struct {
 	nb int64     // number of unread bytes for current file entry
 }
 
-// A sparseFileReader is a numBytesReader for reading sparse file data from a
+// A sparseFileReader is a numBytesReader for reading sparse file data from a tar archive.
-// tar archive.
 type sparseFileReader struct {
-	rfr   numBytesReader // Reads the sparse-encoded file data
+	rfr *regFileReader // reads the sparse-encoded file data
-	sp    []sparseEntry  // The sparse map for the file
+	sp  []sparseEntry  // the sparse map for the file
-	pos   int64          // Keeps track of file position
+	pos int64          // keeps track of file position
-	total int64          // Total size of the file
+	tot int64          // total size of the file
-}
-
-// A sparseEntry holds a single entry in a sparse file's sparse map.
-//
-// Sparse files are represented using a series of sparseEntrys.
-// Despite the name, a sparseEntry represents an actual data fragment that
-// references data found in the underlying archive stream. All regions not
-// covered by a sparseEntry are logically filled with zeros.
-//
-// For example, if the underlying raw file contains the 10-byte data:
-//	var compactData = "abcdefgh"
-//
-// And the sparse map has the following entries:
-//	var sp = []sparseEntry{
-//		{offset: 2,  numBytes: 5} // Data fragment for [2..7]
-//		{offset: 18, numBytes: 3} // Data fragment for [18..21]
-//	}
-//
-// Then the content of the resulting sparse file with a "real" size of 25 is:
-//	var sparseData = "\x00"*2 + "abcde" + "\x00"*11 + "fgh" + "\x00"*4
-type sparseEntry struct {
-	offset   int64 // Starting position of the fragment
-	numBytes int64 // Length of the fragment
 }
 
 // Keywords for GNU sparse files in a PAX extended header
@@ -138,6 +109,7 @@ 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 hdr *Header
 	if tr.RawAccounting {
 		if tr.rawBytes == nil {
 			tr.rawBytes = bytes.NewBuffer(nil)
@@ -145,88 +117,98 @@ func (tr *Reader) Next() (*Header, error) {
 			tr.rawBytes.Reset()
 		}
 	}
-
+	if tr.err == nil {
-	if tr.err != nil {
+		tr.skipUnread()
-		return nil, tr.err
 	}
-
+	if tr.err != nil {
-	var hdr *Header
+		return hdr, tr.err
-	var extHdrs map[string]string
+	}
-
+	hdr = tr.readHeader()
-	// Externally, Next iterates through the tar archive as if it is a series of
+	if hdr == nil {
-	// files. Internally, the tar format often uses fake "files" to add meta
+		return hdr, tr.err
-	// data that describes the next file. These meta data "files" should not
+	}
-	// normally be visible to the outside. As such, this loop iterates through
+	// Check for PAX/GNU header.
-	// one or more "header files" until it finds a "normal file".
+	switch hdr.Typeflag {
-loop:
+	case TypeXHeader:
-	for {
+		//  PAX extended header
-		tr.err = tr.skipUnread()
+		headers, err := parsePAX(tr)
+		if err != nil {
+			return nil, err
+		}
+		// We actually read the whole file,
+		// but this skips alignment padding
+		tr.skipUnread()
 		if tr.err != nil {
 			return nil, tr.err
 		}
-
 		hdr = tr.readHeader()
-		if tr.err != nil {
+		if hdr == nil {
 			return nil, tr.err
 		}
-		// Check for PAX/GNU special headers and files.
+		mergePAX(hdr, headers)
-		switch hdr.Typeflag {
-		case TypeXHeader:
-			extHdrs, tr.err = parsePAX(tr)
-			if tr.err != nil {
-				return nil, tr.err
-			}
-			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 {
+		// Check for a PAX format sparse file
-				if _, tr.err = tr.rawBytes.Write(realname); tr.err != nil {
+		sp, err := tr.checkForGNUSparsePAXHeaders(hdr, headers)
-					return nil, tr.err
+		if err != nil {
-				}
+			tr.err = err
-			}
+			return nil, err
-
+		}
-			// Convert GNU extensions to use PAX headers.
+		if sp != nil {
-			if extHdrs == nil {
+			// Current file is a PAX format GNU sparse file.
-				extHdrs = make(map[string]string)
+			// Set the current file reader to a sparse file reader.
-			}
+			tr.curr = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
-			var p parser
+		}
-			switch hdr.Typeflag {
+		return hdr, nil
-			case TypeGNULongName:
+	case TypeGNULongName:
-				extHdrs[paxPath] = p.parseString(realname)
+		// We have a GNU long name header. Its contents are the real file name.
-			case TypeGNULongLink:
+		realname, err := ioutil.ReadAll(tr)
-				extHdrs[paxLinkpath] = p.parseString(realname)
+		if err != nil {
-			}
+			return nil, err
-			if p.err != nil {
+		}
-				tr.err = p.err
+		var buf []byte
-				return nil, tr.err
+		if tr.RawAccounting {
-			}
+			if _, err = tr.rawBytes.Write(realname); err != nil {
-			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
 			}
-			if sp != nil {
+			buf = make([]byte, tr.rawBytes.Len())
-				// Current file is a PAX format GNU sparse file.
+			copy(buf[:], tr.RawBytes())
-				// 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, 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 = cString(realname)
+		return hdr, err
+	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.Linkname = cString(realname)
+		return hdr, err
 	}
-	return hdr, nil
+	return hdr, tr.err
 }
 
 // checkForGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers. If they are found, then
@@ -403,7 +385,6 @@ func parsePAX(r io.Reader) (map[string]string, error) {
 			return nil, err
 		}
 	}
-	sbuf := string(buf)
 
 	// For GNU PAX sparse format 0.0 support.
 	// This function transforms the sparse format 0.0 headers into sparse format 0.1 headers.
@@ -412,17 +393,35 @@ func parsePAX(r io.Reader) (map[string]string, error) {
 	headers := make(map[string]string)
 	// Each record is constructed as
 	//     "%d %s=%s\n", length, keyword, value
-	for len(sbuf) > 0 {
+	for len(buf) > 0 {
-		key, value, residual, err := parsePAXRecord(sbuf)
+		// or the header was empty to start with.
-		if err != nil {
+		var sp int
+		// The size field ends at the first space.
+		sp = bytes.IndexByte(buf, ' ')
+		if sp == -1 {
 			return nil, ErrHeader
 		}
-		sbuf = residual
+		// Parse the first token as a decimal integer.
+		n, err := strconv.ParseInt(string(buf[:sp]), 10, 0)
+		if err != nil || n < 5 || int64(len(buf)) < n {
+			return nil, ErrHeader
+		}
+		// Extract everything between the decimal and the n -1 on the
+		// beginning to eat the ' ', -1 on the end to skip the newline.
+		var record []byte
+		record, buf = buf[sp+1:n-1], buf[n:]
+		// The first equals is guaranteed to mark the end of the key.
+		// Everything else is value.
+		eq := bytes.IndexByte(record, '=')
+		if eq == -1 {
+			return nil, ErrHeader
+		}
+		key, value := record[:eq], record[eq+1:]
 
 		keyStr := string(key)
 		if keyStr == paxGNUSparseOffset || keyStr == paxGNUSparseNumBytes {
 			// GNU sparse format 0.0 special key. Write to sparseMap instead of using the headers map.
-			sparseMap.WriteString(value)
+			sparseMap.Write(value)
 			sparseMap.Write([]byte{','})
 		} else {
 			// Normal key. Set the value in the headers map.
@@ -437,42 +436,9 @@ func parsePAX(r io.Reader) (map[string]string, error) {
 	return headers, nil
 }
 
-// parsePAXRecord parses the input PAX record string into a key-value pair.
+// cString parses bytes as a NUL-terminated C-style string.
-// If parsing is successful, it will slice off the currently read record and
-// return the remainder as r.
-//
-// A PAX record is of the following form:
-//	"%d %s=%s\n" % (size, key, value)
-func parsePAXRecord(s string) (k, v, r string, err error) {
-	// The size field ends at the first space.
-	sp := strings.IndexByte(s, ' ')
-	if sp == -1 {
-		return "", "", s, ErrHeader
-	}
-
-	// Parse the first token as a decimal integer.
-	n, perr := strconv.ParseInt(s[:sp], 10, 0) // Intentionally parse as native int
-	if perr != nil || n < 5 || int64(len(s)) < n {
-		return "", "", s, ErrHeader
-	}
-
-	// Extract everything between the space and the final newline.
-	rec, nl, rem := s[sp+1:n-1], s[n-1:n], s[n:]
-	if nl != "\n" {
-		return "", "", s, ErrHeader
-	}
-
-	// The first equals separates the key from the value.
-	eq := strings.IndexByte(rec, '=')
-	if eq == -1 {
-		return "", "", s, ErrHeader
-	}
-	return rec[:eq], rec[eq+1:], rem, nil
-}
-
-// parseString parses bytes as a NUL-terminated C-style string.
 // If a NUL byte is not found then the whole slice is returned as a string.
-func (*parser) parseString(b []byte) string {
+func cString(b []byte) string {
 	n := 0
 	for n < len(b) && b[n] != 0 {
 		n++
@@ -480,51 +446,19 @@ func (*parser) parseString(b []byte) string {
 	return string(b[0:n])
 }
 
-// parseNumeric parses the input as being encoded in either base-256 or octal.
+func (tr *Reader) octal(b []byte) int64 {
-// This function may return negative numbers.
+	// Check for binary format first.
-// If parsing fails or an integer overflow occurs, err will be set.
-func (p *parser) parseNumeric(b []byte) int64 {
-	// Check for base-256 (binary) format first.
-	// If the first bit is set, then all following bits constitute a two's
-	// complement encoded number in big-endian byte order.
 	if len(b) > 0 && b[0]&0x80 != 0 {
-		// Handling negative numbers relies on the following identity:
+		var x int64
-		//	-a-1 == ^a
-		//
-		// If the number is negative, we use an inversion mask to invert the
-		// data bytes and treat the value as an unsigned number.
-		var inv byte // 0x00 if positive or zero, 0xff if negative
-		if b[0]&0x40 != 0 {
-			inv = 0xff
-		}
-
-		var x uint64
 		for i, c := range b {
-			c ^= inv // Inverts c only if inv is 0xff, otherwise does nothing
 			if i == 0 {
-				c &= 0x7f // Ignore signal bit in first byte
+				c &= 0x7f // ignore signal bit in first byte
 			}
-			if (x >> 56) > 0 {
+			x = x<<8 | int64(c)
-				p.err = ErrHeader // Integer overflow
-				return 0
-			}
-			x = x<<8 | uint64(c)
 		}
-		if (x >> 63) > 0 {
+		return x
-			p.err = ErrHeader // Integer overflow
-			return 0
-		}
-		if inv == 0xff {
-			return ^int64(x)
-		}
-		return int64(x)
 	}
 
-	// Normal case is base-8 (octal) format.
-	return p.parseOctal(b)
-}
-
-func (p *parser) parseOctal(b []byte) int64 {
 	// Because unused fields are filled with NULs, we need
 	// to skip leading NULs. Fields may also be padded with
 	// spaces or NULs.
@@ -535,55 +469,27 @@ func (p *parser) parseOctal(b []byte) int64 {
 	if len(b) == 0 {
 		return 0
 	}
-	x, perr := strconv.ParseUint(p.parseString(b), 8, 64)
+	x, err := strconv.ParseUint(cString(b), 8, 64)
-	if perr != nil {
+	if err != nil {
-		p.err = ErrHeader
+		tr.err = err
 	}
 	return int64(x)
 }
 
-// skipUnread skips any unread bytes in the existing file entry, as well as any
+// skipUnread skips any unread bytes in the existing file entry, as well as any alignment padding.
-// alignment padding. It returns io.ErrUnexpectedEOF if any io.EOF is
+func (tr *Reader) skipUnread() {
-// encountered in the data portion; it is okay to hit io.EOF in the padding.
+	nr := tr.numBytes() + tr.pad // number of bytes to skip
-//
-// Note that this function still works properly even when sparse files are being
-// used since numBytes returns the bytes remaining in the underlying io.Reader.
-func (tr *Reader) skipUnread() error {
-	dataSkip := tr.numBytes()      // Number of data bytes to skip
-	totalSkip := dataSkip + tr.pad // Total number of bytes to skip
 	tr.curr, tr.pad = nil, 0
 	if tr.RawAccounting {
-		_, tr.err = io.CopyN(tr.rawBytes, tr.r, totalSkip)
+		_, tr.err = io.CopyN(tr.rawBytes, tr.r, nr)
-		return tr.err
+		return
 	}
-	// If possible, Seek to the last byte before the end of the data section.
+	if sr, ok := tr.r.(io.Seeker); ok {
-	// Do this because Seek is often lazy about reporting errors; this will mask
+		if _, err := sr.Seek(nr, os.SEEK_CUR); err == nil {
-	// the fact that the tar stream may be truncated. We can rely on the
+			return
-	// io.CopyN done shortly afterwards to trigger any IO errors.
-	var seekSkipped int64 // Number of bytes skipped via Seek
-	if sr, ok := tr.r.(io.Seeker); ok && dataSkip > 1 {
-		// Not all io.Seeker can actually Seek. For example, os.Stdin implements
-		// io.Seeker, but calling Seek always returns an error and performs
-		// no action. Thus, we try an innocent seek to the current position
-		// to see if Seek is really supported.
-		pos1, err := sr.Seek(0, os.SEEK_CUR)
-		if err == nil {
-			// Seek seems supported, so perform the real Seek.
-			pos2, err := sr.Seek(dataSkip-1, os.SEEK_CUR)
-			if err != nil {
-				tr.err = err
-				return tr.err
-			}
-			seekSkipped = pos2 - pos1
 		}
 	}
-
+	_, tr.err = io.CopyN(ioutil.Discard, tr.r, nr)
-	var copySkipped int64 // Number of bytes skipped via CopyN
-	copySkipped, tr.err = io.CopyN(ioutil.Discard, tr.r, totalSkip-seekSkipped)
-	if tr.err == io.EOF && seekSkipped+copySkipped < dataSkip {
-		tr.err = io.ErrUnexpectedEOF
-	}
-	return tr.err
 }
 
 func (tr *Reader) verifyChecksum(header []byte) bool {
@@ -591,32 +497,23 @@ func (tr *Reader) verifyChecksum(header []byte) bool {
 		return false
 	}
 
-	var p parser
+	given := tr.octal(header[148:156])
-	given := p.parseOctal(header[148:156])
 	unsigned, signed := checksum(header)
-	return p.err == nil && (given == unsigned || given == signed)
+	return given == unsigned || given == signed
 }
 
-// readHeader reads the next block header and assumes that the underlying reader
-// is already aligned to a block boundary.
-//
-// The err will be set to io.EOF only when one of the following occurs:
-//	* Exactly 0 bytes are read and EOF is hit.
-//	* Exactly 1 block of zeros is read and EOF is hit.
-//	* At least 2 blocks of zeros are read.
 func (tr *Reader) readHeader() *Header {
 	header := tr.hdrBuff[:]
 	copy(header, zeroBlock)
 
-	if n, err := io.ReadFull(tr.r, header); err != nil {
+	if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
-		tr.err = err
 		// because it could read some of the block, but reach EOF first
 		if tr.err == io.EOF && tr.RawAccounting {
-			if _, err := tr.rawBytes.Write(header[:n]); err != nil {
+			if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
-				tr.err = err
+				return nil
 			}
 		}
-		return nil // io.EOF is okay here
+		return nil
 	}
 	if tr.RawAccounting {
 		if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
@@ -626,15 +523,14 @@ func (tr *Reader) readHeader() *Header {
 
 	// Two blocks of zero bytes marks the end of the archive.
 	if bytes.Equal(header, zeroBlock[0:blockSize]) {
-		if n, err := io.ReadFull(tr.r, header); err != nil {
+		if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
-			tr.err = err
 			// because it could read some of the block, but reach EOF first
 			if tr.err == io.EOF && tr.RawAccounting {
-				if _, err := tr.rawBytes.Write(header[:n]); err != nil {
+				if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
-					tr.err = err
+					return nil
 				}
 			}
-			return nil // io.EOF is okay here
+			return nil
 		}
 		if tr.RawAccounting {
 			if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
@@ -655,19 +551,22 @@ func (tr *Reader) readHeader() *Header {
 	}
 
 	// Unpack
-	var p parser
 	hdr := new(Header)
 	s := slicer(header)
 
-	hdr.Name = p.parseString(s.next(100))
+	hdr.Name = cString(s.next(100))
-	hdr.Mode = p.parseNumeric(s.next(8))
+	hdr.Mode = tr.octal(s.next(8))
-	hdr.Uid = int(p.parseNumeric(s.next(8)))
+	hdr.Uid = int(tr.octal(s.next(8)))
-	hdr.Gid = int(p.parseNumeric(s.next(8)))
+	hdr.Gid = int(tr.octal(s.next(8)))
-	hdr.Size = p.parseNumeric(s.next(12))
+	hdr.Size = tr.octal(s.next(12))
-	hdr.ModTime = time.Unix(p.parseNumeric(s.next(12)), 0)
+	if hdr.Size < 0 {
+		tr.err = ErrHeader
+		return nil
+	}
+	hdr.ModTime = time.Unix(tr.octal(s.next(12)), 0)
 	s.next(8) // chksum
 	hdr.Typeflag = s.next(1)[0]
-	hdr.Linkname = p.parseString(s.next(100))
+	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,
@@ -687,76 +586,70 @@ func (tr *Reader) readHeader() *Header {
 
 	switch format {
 	case "posix", "gnu", "star":
-		hdr.Uname = p.parseString(s.next(32))
+		hdr.Uname = cString(s.next(32))
-		hdr.Gname = p.parseString(s.next(32))
+		hdr.Gname = cString(s.next(32))
 		devmajor := s.next(8)
 		devminor := s.next(8)
 		if hdr.Typeflag == TypeChar || hdr.Typeflag == TypeBlock {
-			hdr.Devmajor = p.parseNumeric(devmajor)
+			hdr.Devmajor = tr.octal(devmajor)
-			hdr.Devminor = p.parseNumeric(devminor)
+			hdr.Devminor = tr.octal(devminor)
 		}
 		var prefix string
 		switch format {
 		case "posix", "gnu":
-			prefix = p.parseString(s.next(155))
+			prefix = cString(s.next(155))
 		case "star":
-			prefix = p.parseString(s.next(131))
+			prefix = cString(s.next(131))
-			hdr.AccessTime = time.Unix(p.parseNumeric(s.next(12)), 0)
+			hdr.AccessTime = time.Unix(tr.octal(s.next(12)), 0)
-			hdr.ChangeTime = time.Unix(p.parseNumeric(s.next(12)), 0)
+			hdr.ChangeTime = time.Unix(tr.octal(s.next(12)), 0)
 		}
 		if len(prefix) > 0 {
 			hdr.Name = prefix + "/" + hdr.Name
 		}
 	}
 
-	if p.err != nil {
+	if tr.err != nil {
-		tr.err = p.err
-		return nil
-	}
-
-	nb := hdr.Size
-	if isHeaderOnlyType(hdr.Typeflag) {
-		nb = 0
-	}
-	if nb < 0 {
 		tr.err = ErrHeader
 		return nil
 	}
 
-	// Set the current file reader.
+	// Maximum value of hdr.Size is 64 GB (12 octal digits),
+	// so there's no risk of int64 overflowing.
+	nb := int64(hdr.Size)
 	tr.pad = -nb & (blockSize - 1) // blockSize is a power of two
+
+	// Set the current file reader.
 	tr.curr = &regFileReader{r: tr.r, nb: nb}
 
 	// Check for old GNU sparse format entry.
 	if hdr.Typeflag == TypeGNUSparse {
 		// Get the real size of the file.
-		hdr.Size = p.parseNumeric(header[483:495])
+		hdr.Size = tr.octal(header[483:495])
-		if p.err != nil {
-			tr.err = p.err
-			return nil
-		}
 
 		// Read the sparse map.
 		sp := tr.readOldGNUSparseMap(header)
 		if tr.err != nil {
 			return nil
 		}
-
 		// Current file is a GNU sparse file. Update the current file reader.
-		tr.curr, tr.err = newSparseFileReader(tr.curr, sp, hdr.Size)
+		tr.curr = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
-		if tr.err != nil {
-			return nil
-		}
 	}
 
 	return hdr
 }
 
+// A sparseEntry holds a single entry in a sparse file's sparse map.
+// A sparse entry indicates the offset and size in a sparse file of a
+// block of data.
+type sparseEntry struct {
+	offset   int64
+	numBytes int64
+}
+
 // readOldGNUSparseMap reads the sparse map as stored in the old GNU sparse format.
 // The sparse map is stored in the tar header if it's small enough. If it's larger than four entries,
 // then one or more extension headers are used to store the rest of the sparse map.
 func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
-	var p parser
 	isExtended := header[oldGNUSparseMainHeaderIsExtendedOffset] != 0
 	spCap := oldGNUSparseMainHeaderNumEntries
 	if isExtended {
@@ -767,10 +660,10 @@ func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
 
 	// Read the four entries from the main tar header
 	for i := 0; i < oldGNUSparseMainHeaderNumEntries; i++ {
-		offset := p.parseNumeric(s.next(oldGNUSparseOffsetSize))
+		offset := tr.octal(s.next(oldGNUSparseOffsetSize))
-		numBytes := p.parseNumeric(s.next(oldGNUSparseNumBytesSize))
+		numBytes := tr.octal(s.next(oldGNUSparseNumBytesSize))
-		if p.err != nil {
+		if tr.err != nil {
-			tr.err = p.err
+			tr.err = ErrHeader
 			return nil
 		}
 		if offset == 0 && numBytes == 0 {
@@ -794,10 +687,10 @@ func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
 		isExtended = sparseHeader[oldGNUSparseExtendedHeaderIsExtendedOffset] != 0
 		s = slicer(sparseHeader)
 		for i := 0; i < oldGNUSparseExtendedHeaderNumEntries; i++ {
-			offset := p.parseNumeric(s.next(oldGNUSparseOffsetSize))
+			offset := tr.octal(s.next(oldGNUSparseOffsetSize))
-			numBytes := p.parseNumeric(s.next(oldGNUSparseNumBytesSize))
+			numBytes := tr.octal(s.next(oldGNUSparseNumBytesSize))
-			if p.err != nil {
+			if tr.err != nil {
-				tr.err = p.err
+				tr.err = ErrHeader
 				return nil
 			}
 			if offset == 0 && numBytes == 0 {
@@ -809,111 +702,134 @@ func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
 	return sp
 }
 
-// readGNUSparseMap1x0 reads the sparse map as stored in GNU's PAX sparse format
+// readGNUSparseMap1x0 reads the sparse map as stored in GNU's PAX sparse format version 1.0.
-// version 1.0. The format of the sparse map consists of a series of
+// The sparse map is stored just before the file data and padded out to the nearest block boundary.
-// newline-terminated numeric fields. The first field is the number of entries
-// and is always present. Following this are the entries, consisting of two
-// fields (offset, numBytes). This function must stop reading at the end
-// boundary of the block containing the last newline.
-//
-// Note that the GNU manual says that numeric values should be encoded in octal
-// format. However, the GNU tar utility itself outputs these values in decimal.
-// As such, this library treats values as being encoded in decimal.
 func readGNUSparseMap1x0(r io.Reader) ([]sparseEntry, error) {
-	var cntNewline int64
+	buf := make([]byte, 2*blockSize)
-	var buf bytes.Buffer
+	sparseHeader := buf[:blockSize]
-	var blk = make([]byte, blockSize)
 
-	// feedTokens copies data in numBlock chunks from r into buf until there are
+	// readDecimal is a helper function to read a decimal integer from the sparse map
-	// at least cnt newlines in buf. It will not read more blocks than needed.
+	// while making sure to read from the file in blocks of size blockSize
-	var feedTokens = func(cnt int64) error {
+	readDecimal := func() (int64, error) {
-		for cntNewline < cnt {
+		// Look for newline
-			if _, err := io.ReadFull(r, blk); err != nil {
+		nl := bytes.IndexByte(sparseHeader, '\n')
-				if err == io.EOF {
+		if nl == -1 {
-					err = io.ErrUnexpectedEOF
+			if len(sparseHeader) >= blockSize {
-				}
+				// This is an error
-				return err
+				return 0, ErrHeader
 			}
-			buf.Write(blk)
+			oldLen := len(sparseHeader)
-			for _, c := range blk {
+			newLen := oldLen + blockSize
-				if c == '\n' {
+			if cap(sparseHeader) < newLen {
-					cntNewline++
+				// There's more header, but we need to make room for the next block
+				copy(buf, sparseHeader)
+				sparseHeader = buf[:newLen]
+			} else {
+				// There's more header, and we can just reslice
+				sparseHeader = sparseHeader[:newLen]
+			}
+
+			// Now that sparseHeader is large enough, read next block
+			if _, err := io.ReadFull(r, sparseHeader[oldLen:newLen]); err != nil {
+				return 0, err
+			}
+			// leaving this function for io.Reader makes it more testable
+			if tr, ok := r.(*Reader); ok && tr.RawAccounting {
+				if _, err := tr.rawBytes.Write(sparseHeader[oldLen:newLen]); err != nil {
+					return 0, err
 				}
 			}
+
+			// Look for a newline in the new data
+			nl = bytes.IndexByte(sparseHeader[oldLen:newLen], '\n')
+			if nl == -1 {
+				// This is an error
+				return 0, ErrHeader
+			}
+			nl += oldLen // We want the position from the beginning
 		}
-		return nil
+		// Now that we've found a newline, read a number
+		n, err := strconv.ParseInt(string(sparseHeader[:nl]), 10, 0)
+		if err != nil {
+			return 0, ErrHeader
+		}
+
+		// Update sparseHeader to consume this number
+		sparseHeader = sparseHeader[nl+1:]
+		return n, nil
 	}
 
-	// nextToken gets the next token delimited by a newline. This assumes that
+	// Read the first block
-	// at least one newline exists in the buffer.
+	if _, err := io.ReadFull(r, sparseHeader); err != nil {
-	var nextToken = func() string {
-		cntNewline--
-		tok, _ := buf.ReadString('\n')
-		return tok[:len(tok)-1] // Cut off newline
-	}
-
-	// Parse for the number of entries.
-	// Use integer overflow resistant math to check this.
-	if err := feedTokens(1); err != nil {
 		return nil, err
 	}
-	numEntries, err := strconv.ParseInt(nextToken(), 10, 0) // Intentionally parse as native int
+	// leaving this function for io.Reader makes it more testable
-	if err != nil || numEntries < 0 || int(2*numEntries) < int(numEntries) {
+	if tr, ok := r.(*Reader); ok && tr.RawAccounting {
-		return nil, ErrHeader
+		if _, err := tr.rawBytes.Write(sparseHeader); err != nil {
+			return nil, err
+		}
 	}
 
-	// Parse for all member entries.
+	// The first line contains the number of entries
-	// numEntries is trusted after this since a potential attacker must have
+	numEntries, err := readDecimal()
-	// committed resources proportional to what this library used.
+	if err != nil {
-	if err := feedTokens(2 * numEntries); err != nil {
 		return nil, err
 	}
+
+	// Read all the entries
 	sp := make([]sparseEntry, 0, numEntries)
 	for i := int64(0); i < numEntries; i++ {
-		offset, err := strconv.ParseInt(nextToken(), 10, 64)
+		// Read the offset
+		offset, err := readDecimal()
 		if err != nil {
-			return nil, ErrHeader
+			return nil, err
 		}
-		numBytes, err := strconv.ParseInt(nextToken(), 10, 64)
+		// Read numBytes
+		numBytes, err := readDecimal()
 		if err != nil {
-			return nil, ErrHeader
+			return nil, err
 		}
+
 		sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
 	}
+
 	return sp, nil
 }
 
-// readGNUSparseMap0x1 reads the sparse map as stored in GNU's PAX sparse format
+// readGNUSparseMap0x1 reads the sparse map as stored in GNU's PAX sparse format version 0.1.
-// version 0.1. The sparse map is stored in the PAX headers.
+// The sparse map is stored in the PAX headers.
-func readGNUSparseMap0x1(extHdrs map[string]string) ([]sparseEntry, error) {
+func readGNUSparseMap0x1(headers map[string]string) ([]sparseEntry, error) {
-	// Get number of entries.
+	// Get number of entries
-	// Use integer overflow resistant math to check this.
+	numEntriesStr, ok := headers[paxGNUSparseNumBlocks]
-	numEntriesStr := extHdrs[paxGNUSparseNumBlocks]
+	if !ok {
-	numEntries, err := strconv.ParseInt(numEntriesStr, 10, 0) // Intentionally parse as native int
+		return nil, ErrHeader
-	if err != nil || numEntries < 0 || int(2*numEntries) < int(numEntries) {
+	}
+	numEntries, err := strconv.ParseInt(numEntriesStr, 10, 0)
+	if err != nil {
 		return nil, ErrHeader
 	}
 
-	// There should be two numbers in sparseMap for each entry.
+	sparseMap := strings.Split(headers[paxGNUSparseMap], ",")
-	sparseMap := strings.Split(extHdrs[paxGNUSparseMap], ",")
+
+	// There should be two numbers in sparseMap for each entry
 	if int64(len(sparseMap)) != 2*numEntries {
 		return nil, ErrHeader
 	}
 
-	// Loop through the entries in the sparse map.
+	// Loop through the entries in the sparse map
-	// numEntries is trusted now.
 	sp := make([]sparseEntry, 0, numEntries)
 	for i := int64(0); i < numEntries; i++ {
-		offset, err := strconv.ParseInt(sparseMap[2*i], 10, 64)
+		offset, err := strconv.ParseInt(sparseMap[2*i], 10, 0)
 		if err != nil {
 			return nil, ErrHeader
 		}
-		numBytes, err := strconv.ParseInt(sparseMap[2*i+1], 10, 64)
+		numBytes, err := strconv.ParseInt(sparseMap[2*i+1], 10, 0)
 		if err != nil {
 			return nil, ErrHeader
 		}
 		sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
 	}
+
 	return sp, nil
 }
 
@@ -930,18 +846,10 @@ func (tr *Reader) numBytes() int64 {
 // Read reads from the current entry in the tar archive.
 // It returns 0, io.EOF when it reaches the end of that entry,
 // until Next is called to advance to the next entry.
-//
-// Calling Read on special types like TypeLink, TypeSymLink, TypeChar,
-// TypeBlock, TypeDir, and TypeFifo returns 0, io.EOF regardless of what
-// the Header.Size claims.
 func (tr *Reader) Read(b []byte) (n int, err error) {
-	if tr.err != nil {
-		return 0, tr.err
-	}
 	if tr.curr == nil {
 		return 0, io.EOF
 	}
-
 	n, err = tr.curr.Read(b)
 	if err != nil && err != io.EOF {
 		tr.err = err
@@ -971,33 +879,9 @@ func (rfr *regFileReader) numBytes() int64 {
 	return rfr.nb
 }
 
-// newSparseFileReader creates a new sparseFileReader, but validates all of the
+// readHole reads a sparse file hole ending at offset toOffset
-// sparse entries before doing so.
+func (sfr *sparseFileReader) readHole(b []byte, toOffset int64) int {
-func newSparseFileReader(rfr numBytesReader, sp []sparseEntry, total int64) (*sparseFileReader, error) {
+	n64 := toOffset - sfr.pos
-	if total < 0 {
-		return nil, ErrHeader // Total size cannot be negative
-	}
-
-	// Validate all sparse entries. These are the same checks as performed by
-	// the BSD tar utility.
-	for i, s := range sp {
-		switch {
-		case s.offset < 0 || s.numBytes < 0:
-			return nil, ErrHeader // Negative values are never okay
-		case s.offset > math.MaxInt64-s.numBytes:
-			return nil, ErrHeader // Integer overflow with large length
-		case s.offset+s.numBytes > total:
-			return nil, ErrHeader // Region extends beyond the "real" size
-		case i > 0 && sp[i-1].offset+sp[i-1].numBytes > s.offset:
-			return nil, ErrHeader // Regions can't overlap and must be in order
-		}
-	}
-	return &sparseFileReader{rfr: rfr, sp: sp, total: total}, nil
-}
-
-// readHole reads a sparse hole ending at endOffset.
-func (sfr *sparseFileReader) readHole(b []byte, endOffset int64) int {
-	n64 := endOffset - sfr.pos
 	if n64 > int64(len(b)) {
 		n64 = int64(len(b))
 	}
@@ -1011,54 +895,49 @@ func (sfr *sparseFileReader) readHole(b []byte, endOffset int64) int {
 
 // Read reads the sparse file data in expanded form.
 func (sfr *sparseFileReader) Read(b []byte) (n int, err error) {
-	// Skip past all empty fragments.
-	for len(sfr.sp) > 0 && sfr.sp[0].numBytes == 0 {
-		sfr.sp = sfr.sp[1:]
-	}
-
-	// If there are no more fragments, then it is possible that there
-	// is one last sparse hole.
 	if len(sfr.sp) == 0 {
-		// This behavior matches the BSD tar utility.
+		// No more data fragments to read from.
-		// However, GNU tar stops returning data even if sfr.total is unmet.
+		if sfr.pos < sfr.tot {
-		if sfr.pos < sfr.total {
+			// We're in the last hole
-			return sfr.readHole(b, sfr.total), nil
+			n = sfr.readHole(b, sfr.tot)
+			return
 		}
+		// Otherwise, we're at the end of the file
 		return 0, io.EOF
 	}
-
+	if sfr.tot < sfr.sp[0].offset {
-	// In front of a data fragment, so read a hole.
+		return 0, io.ErrUnexpectedEOF
+	}
 	if sfr.pos < sfr.sp[0].offset {
-		return sfr.readHole(b, sfr.sp[0].offset), nil
+		// We're in a hole
+		n = sfr.readHole(b, sfr.sp[0].offset)
+		return
 	}
 
-	// In a data fragment, so read from it.
+	// We're not in a hole, so we'll read from the next data fragment
-	// This math is overflow free since we verify that offset and numBytes can
+	posInFragment := sfr.pos - sfr.sp[0].offset
-	// be safely added when creating the sparseFileReader.
+	bytesLeft := sfr.sp[0].numBytes - posInFragment
-	endPos := sfr.sp[0].offset + sfr.sp[0].numBytes // End offset of fragment
-	bytesLeft := endPos - sfr.pos                   // Bytes left in fragment
 	if int64(len(b)) > bytesLeft {
-		b = b[:bytesLeft]
+		b = b[0:bytesLeft]
 	}
 
 	n, err = sfr.rfr.Read(b)
 	sfr.pos += int64(n)
-	if err == io.EOF {
+
-		if sfr.pos < endPos {
+	if int64(n) == bytesLeft {
-			err = io.ErrUnexpectedEOF // There was supposed to be more data
+		// We're done with this fragment
-		} else if sfr.pos < sfr.total {
+		sfr.sp = sfr.sp[1:]
-			err = nil // There is still an implicit sparse hole at the end
-		}
 	}
 
-	if sfr.pos == endPos {
+	if err == io.EOF && sfr.pos < sfr.tot {
-		sfr.sp = sfr.sp[1:] // We are done with this fragment, so pop it
+		// We reached the end of the last fragment's data, but there's a final hole
+		err = nil
 	}
-	return n, err
+	return
 }
 
 // numBytes returns the number of bytes left to read in the sparse file's
 // sparse-encoded data in the tar archive.
 func (sfr *sparseFileReader) numBytes() int64 {
-	return sfr.rfr.numBytes()
+	return sfr.rfr.nb
 }

archive/tar/tar_test.go

@@ -94,12 +94,13 @@ func TestRoundTrip(t *testing.T) {
 	var b bytes.Buffer
 	tw := NewWriter(&b)
 	hdr := &Header{
-		Name: "file.txt",
+		Name:    "file.txt",
-		Uid:  1 << 21, // too big for 8 octal digits
+		Uid:     1 << 21, // too big for 8 octal digits
-		Size: int64(len(data)),
+		Size:    int64(len(data)),
-		// https://github.com/golang/go/commit/0e3355903d2ebcf5ee9e76096f51ac9a116a9dbb#diff-d7bf2a98d7b57b6ff754ca406f1b7581R105
+		ModTime: time.Now(),
-		ModTime: time.Now().AddDate(0, 0, 0).Round(1 * time.Second),
 	}
+	// tar only supports second precision.
+	hdr.ModTime = hdr.ModTime.Add(-time.Duration(hdr.ModTime.Nanosecond()) * time.Nanosecond)
 	if err := tw.WriteHeader(hdr); err != nil {
 		t.Fatalf("tw.WriteHeader: %v", err)
 	}

archive/tar/writer.go

@@ -12,8 +12,8 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"path"
-	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -23,6 +23,7 @@ var (
 	ErrWriteTooLong    = errors.New("archive/tar: write too long")
 	ErrFieldTooLong    = errors.New("archive/tar: header field too long")
 	ErrWriteAfterClose = errors.New("archive/tar: write after close")
+	errNameTooLong     = errors.New("archive/tar: name too long")
 	errInvalidHeader   = errors.New("archive/tar: header field too long or contains invalid values")
 )
 
@@ -42,10 +43,6 @@ type Writer struct {
 	paxHdrBuff [blockSize]byte // buffer to use in writeHeader when writing a pax header
 }
 
-type formatter struct {
-	err error // Last error seen
-}
-
 // NewWriter creates a new Writer writing to w.
 func NewWriter(w io.Writer) *Writer { return &Writer{w: w} }
 
@@ -72,9 +69,17 @@ func (tw *Writer) Flush() error {
 }
 
 // Write s into b, terminating it with a NUL if there is room.
-func (f *formatter) formatString(b []byte, s string) {
+// If the value is too long for the field and allowPax is true add a paxheader record instead
+func (tw *Writer) cString(b []byte, s string, allowPax bool, paxKeyword string, paxHeaders map[string]string) {
+	needsPaxHeader := allowPax && len(s) > len(b) || !isASCII(s)
+	if needsPaxHeader {
+		paxHeaders[paxKeyword] = s
+		return
+	}
 	if len(s) > len(b) {
-		f.err = ErrFieldTooLong
+		if tw.err == nil {
+			tw.err = ErrFieldTooLong
+		}
 		return
 	}
 	ascii := toASCII(s)
@@ -85,40 +90,40 @@ func (f *formatter) formatString(b []byte, s string) {
 }
 
 // Encode x as an octal ASCII string and write it into b with leading zeros.
-func (f *formatter) formatOctal(b []byte, x int64) {
+func (tw *Writer) octal(b []byte, x int64) {
 	s := strconv.FormatInt(x, 8)
 	// leading zeros, but leave room for a NUL.
 	for len(s)+1 < len(b) {
 		s = "0" + s
 	}
-	f.formatString(b, s)
+	tw.cString(b, s, false, paxNone, nil)
 }
 
-// fitsInBase256 reports whether x can be encoded into n bytes using base-256
+// Write x into b, either as octal or as binary (GNUtar/star extension).
-// encoding. Unlike octal encoding, base-256 encoding does not require that the
+// If the value is too long for the field and writingPax is enabled both for the field and the add a paxheader record instead
-// string ends with a NUL character. Thus, all n bytes are available for output.
+func (tw *Writer) numeric(b []byte, x int64, allowPax bool, paxKeyword string, paxHeaders map[string]string) {
-//
+	// Try octal first.
-// If operating in binary mode, this assumes strict GNU binary mode; which means
+	s := strconv.FormatInt(x, 8)
-// that the first byte can only be either 0x80 or 0xff. Thus, the first byte is
+	if len(s) < len(b) {
-// equivalent to the sign bit in two's complement form.
+		tw.octal(b, x)
-func fitsInBase256(n int, x int64) bool {
-	var binBits = uint(n-1) * 8
-	return n >= 9 || (x >= -1<<binBits && x < 1<<binBits)
-}
-
-// Write x into b, as binary (GNUtar/star extension).
-func (f *formatter) formatNumeric(b []byte, x int64) {
-	if fitsInBase256(len(b), x) {
-		for i := len(b) - 1; i >= 0; i-- {
-			b[i] = byte(x)
-			x >>= 8
-		}
-		b[0] |= 0x80 // Highest bit indicates binary format
 		return
 	}
 
-	f.formatOctal(b, 0) // Last resort, just write zero
+	// If it is too long for octal, and pax is preferred, use a pax header
-	f.err = ErrFieldTooLong
+	if allowPax && tw.preferPax {
+		tw.octal(b, 0)
+		s := strconv.FormatInt(x, 10)
+		paxHeaders[paxKeyword] = s
+		return
+	}
+
+	// Too big: use binary (big-endian).
+	tw.usedBinary = true
+	for i := len(b) - 1; x > 0 && i >= 0; i-- {
+		b[i] = byte(x)
+		x >>= 8
+	}
+	b[0] |= 0x80 // highest bit indicates binary format
 }
 
 var (
@@ -157,7 +162,6 @@ func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
 	// subsecond time resolution, but for now let's just capture
 	// too long fields or non ascii characters
 
-	var f formatter
 	var header []byte
 
 	// We need to select which scratch buffer to use carefully,
@@ -172,40 +176,10 @@ func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
 	copy(header, zeroBlock)
 	s := slicer(header)
 
-	// Wrappers around formatter that automatically sets paxHeaders if the
-	// argument extends beyond the capacity of the input byte slice.
-	var formatString = func(b []byte, s string, paxKeyword string) {
-		needsPaxHeader := paxKeyword != paxNone && len(s) > len(b) || !isASCII(s)
-		if needsPaxHeader {
-			paxHeaders[paxKeyword] = s
-			return
-		}
-		f.formatString(b, s)
-	}
-	var formatNumeric = func(b []byte, x int64, paxKeyword string) {
-		// Try octal first.
-		s := strconv.FormatInt(x, 8)
-		if len(s) < len(b) {
-			f.formatOctal(b, x)
-			return
-		}
-
-		// If it is too long for octal, and PAX is preferred, use a PAX header.
-		if paxKeyword != paxNone && tw.preferPax {
-			f.formatOctal(b, 0)
-			s := strconv.FormatInt(x, 10)
-			paxHeaders[paxKeyword] = s
-			return
-		}
-
-		tw.usedBinary = true
-		f.formatNumeric(b, x)
-	}
-
 	// keep a reference to the filename to allow to overwrite it later if we detect that we can use ustar longnames instead of pax
 	pathHeaderBytes := s.next(fileNameSize)
 
-	formatString(pathHeaderBytes, hdr.Name, paxPath)
+	tw.cString(pathHeaderBytes, hdr.Name, true, paxPath, paxHeaders)
 
 	// Handle out of range ModTime carefully.
 	var modTime int64
@@ -213,25 +187,25 @@ func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
 		modTime = hdr.ModTime.Unix()
 	}
 
-	f.formatOctal(s.next(8), hdr.Mode)               // 100:108
+	tw.octal(s.next(8), hdr.Mode)                                   // 100:108
-	formatNumeric(s.next(8), int64(hdr.Uid), paxUid) // 108:116
+	tw.numeric(s.next(8), int64(hdr.Uid), true, paxUid, paxHeaders) // 108:116
-	formatNumeric(s.next(8), int64(hdr.Gid), paxGid) // 116:124
+	tw.numeric(s.next(8), int64(hdr.Gid), true, paxGid, paxHeaders) // 116:124
-	formatNumeric(s.next(12), hdr.Size, paxSize)     // 124:136
+	tw.numeric(s.next(12), hdr.Size, true, paxSize, paxHeaders)     // 124:136
-	formatNumeric(s.next(12), modTime, paxNone)      // 136:148 --- consider using pax for finer granularity
+	tw.numeric(s.next(12), modTime, false, paxNone, nil)            // 136:148 --- consider using pax for finer granularity
-	s.next(8)                                        // chksum (148:156)
+	s.next(8)                                                       // chksum (148:156)
-	s.next(1)[0] = hdr.Typeflag                      // 156:157
+	s.next(1)[0] = hdr.Typeflag                                     // 156:157
 
-	formatString(s.next(100), hdr.Linkname, paxLinkpath)
+	tw.cString(s.next(100), hdr.Linkname, true, paxLinkpath, paxHeaders)
 
-	copy(s.next(8), []byte("ustar\x0000"))          // 257:265
+	copy(s.next(8), []byte("ustar\x0000"))                        // 257:265
-	formatString(s.next(32), hdr.Uname, paxUname)   // 265:297
+	tw.cString(s.next(32), hdr.Uname, true, paxUname, paxHeaders) // 265:297
-	formatString(s.next(32), hdr.Gname, paxGname)   // 297:329
+	tw.cString(s.next(32), hdr.Gname, true, paxGname, paxHeaders) // 297:329
-	formatNumeric(s.next(8), hdr.Devmajor, paxNone) // 329:337
+	tw.numeric(s.next(8), hdr.Devmajor, false, paxNone, nil)      // 329:337
-	formatNumeric(s.next(8), hdr.Devminor, paxNone) // 337:345
+	tw.numeric(s.next(8), hdr.Devminor, false, paxNone, nil)      // 337:345
 
 	// keep a reference to the prefix to allow to overwrite it later if we detect that we can use ustar longnames instead of pax
 	prefixHeaderBytes := s.next(155)
-	formatString(prefixHeaderBytes, "", paxNone) // 345:500  prefix
+	tw.cString(prefixHeaderBytes, "", false, paxNone, nil) // 345:500  prefix
 
 	// Use the GNU magic instead of POSIX magic if we used any GNU extensions.
 	if tw.usedBinary {
@@ -241,26 +215,37 @@ func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
 	_, paxPathUsed := paxHeaders[paxPath]
 	// try to use a ustar header when only the name is too long
 	if !tw.preferPax && len(paxHeaders) == 1 && paxPathUsed {
-		prefix, suffix, ok := splitUSTARPath(hdr.Name)
+		suffix := hdr.Name
-		if ok {
+		prefix := ""
-			// Since we can encode in USTAR format, disable PAX header.
+		if len(hdr.Name) > fileNameSize && isASCII(hdr.Name) {
-			delete(paxHeaders, paxPath)
+			var err error
+			prefix, suffix, err = tw.splitUSTARLongName(hdr.Name)
+			if err == nil {
+				// ok we can use a ustar long name instead of pax, now correct the fields
 
-			// Update the path fields
+				// remove the path field from the pax header. this will suppress the pax header
-			formatString(pathHeaderBytes, suffix, paxNone)
+				delete(paxHeaders, paxPath)
-			formatString(prefixHeaderBytes, prefix, paxNone)
+
+				// update the path fields
+				tw.cString(pathHeaderBytes, suffix, false, paxNone, nil)
+				tw.cString(prefixHeaderBytes, prefix, false, paxNone, nil)
+
+				// Use the ustar magic if we used ustar long names.
+				if len(prefix) > 0 && !tw.usedBinary {
+					copy(header[257:265], []byte("ustar\x00"))
+				}
+			}
 		}
 	}
 
 	// The chksum field is terminated by a NUL and a space.
 	// This is different from the other octal fields.
 	chksum, _ := checksum(header)
-	f.formatOctal(header[148:155], chksum) // Never fails
+	tw.octal(header[148:155], chksum)
 	header[155] = ' '
 
-	// Check if there were any formatting errors.
+	if tw.err != nil {
-	if f.err != nil {
+		// problem with header; probably integer too big for a field.
-		tw.err = f.err
 		return tw.err
 	}
 
@@ -285,25 +270,28 @@ func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
 	return tw.err
 }
 
-// splitUSTARPath splits a path according to USTAR prefix and suffix rules.
+// writeUSTARLongName splits a USTAR long name hdr.Name.
-// If the path is not splittable, then it will return ("", "", false).
+// name must be < 256 characters. errNameTooLong is returned
-func splitUSTARPath(name string) (prefix, suffix string, ok bool) {
+// if hdr.Name can't be split. The splitting heuristic
+// is compatible with gnu tar.
+func (tw *Writer) splitUSTARLongName(name string) (prefix, suffix string, err error) {
 	length := len(name)
-	if length <= fileNameSize || !isASCII(name) {
+	if length > fileNamePrefixSize+1 {
-		return "", "", false
-	} else if length > fileNamePrefixSize+1 {
 		length = fileNamePrefixSize + 1
 	} else if name[length-1] == '/' {
 		length--
 	}
-
 	i := strings.LastIndex(name[:length], "/")
-	nlen := len(name) - i - 1 // nlen is length of suffix
+	// nlen contains the resulting length in the name field.
-	plen := i                 // plen is length of prefix
+	// plen contains the resulting length in the prefix field.
+	nlen := len(name) - i - 1
+	plen := i
 	if i <= 0 || nlen > fileNameSize || nlen == 0 || plen > fileNamePrefixSize {
-		return "", "", false
+		err = errNameTooLong
+		return
 	}
-	return name[:i], name[i+1:], true
+	prefix, suffix = name[:i], name[i+1:]
+	return
 }
 
 // writePaxHeader writes an extended pax header to the
@@ -316,11 +304,11 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) erro
 	// succeed, and seems harmless enough.
 	ext.ModTime = hdr.ModTime
 	// The spec asks that we namespace our pseudo files
-	// with the current pid.  However, this results in differing outputs
+	// with the current pid.
-	// for identical inputs.  As such, the constant 0 is now used instead.
+	pid := os.Getpid()
-	// golang.org/issue/12358
 	dir, file := path.Split(hdr.Name)
-	fullName := path.Join(dir, "PaxHeaders.0", file)
+	fullName := path.Join(dir,
+		fmt.Sprintf("PaxHeaders.%d", pid), file)
 
 	ascii := toASCII(fullName)
 	if len(ascii) > 100 {
@@ -330,15 +318,8 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) erro
 	// Construct the body
 	var buf bytes.Buffer
 
-	// Keys are sorted before writing to body to allow deterministic output.
+	for k, v := range paxHeaders {
-	var keys []string
+		fmt.Fprint(&buf, paxHeader(k+"="+v))
-	for k := range paxHeaders {
-		keys = append(keys, k)
-	}
-	sort.Strings(keys)
-
-	for _, k := range keys {
-		fmt.Fprint(&buf, formatPAXRecord(k, paxHeaders[k]))
 	}
 
 	ext.Size = int64(len(buf.Bytes()))
@@ -354,18 +335,17 @@ func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) erro
 	return nil
 }
 
-// formatPAXRecord formats a single PAX record, prefixing it with the
+// paxHeader formats a single pax record, prefixing it with the appropriate length
-// appropriate length.
+func paxHeader(msg string) string {
-func formatPAXRecord(k, v string) string {
+	const padding = 2 // Extra padding for space and newline
-	const padding = 3 // Extra padding for ' ', '=', and '\n'
+	size := len(msg) + padding
-	size := len(k) + len(v) + padding
 	size += len(strconv.Itoa(size))
-	record := fmt.Sprintf("%d %s=%s\n", size, k, v)
+	record := fmt.Sprintf("%d %s\n", size, msg)
-
-	// Final adjustment if adding size field increased the record size.
 	if len(record) != size {
+		// Final adjustment if adding size increased
+		// the number of digits in size
 		size = len(record)
-		record = fmt.Sprintf("%d %s=%s\n", size, k, v)
+		record = fmt.Sprintf("%d %s\n", size, msg)
 	}
 	return record
 }

archive/tar/writer_test.go

@@ -9,10 +9,8 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"math"
 	"os"
 	"reflect"
-	"sort"
 	"strings"
 	"testing"
 	"testing/iotest"
@@ -293,7 +291,7 @@ func TestPax(t *testing.T) {
 		t.Fatal(err)
 	}
 	// Simple test to make sure PAX extensions are in effect
-	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
+	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.")) {
 		t.Fatal("Expected at least one PAX header to be written.")
 	}
 	// Test that we can get a long name back out of the archive.
@@ -332,7 +330,7 @@ func TestPaxSymlink(t *testing.T) {
 		t.Fatal(err)
 	}
 	// Simple test to make sure PAX extensions are in effect
-	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
+	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.")) {
 		t.Fatal("Expected at least one PAX header to be written.")
 	}
 	// Test that we can get a long name back out of the archive.
@@ -382,7 +380,7 @@ func TestPaxNonAscii(t *testing.T) {
 		t.Fatal(err)
 	}
 	// Simple test to make sure PAX extensions are in effect
-	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
+	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.")) {
 		t.Fatal("Expected at least one PAX header to be written.")
 	}
 	// Test that we can get a long name back out of the archive.
@@ -441,49 +439,21 @@ func TestPaxXattrs(t *testing.T) {
 	}
 }
 
-func TestPaxHeadersSorted(t *testing.T) {
+func TestPAXHeader(t *testing.T) {
-	fileinfo, err := os.Stat("testdata/small.txt")
+	medName := strings.Repeat("CD", 50)
-	if err != nil {
+	longName := strings.Repeat("AB", 100)
-		t.Fatal(err)
+	paxTests := [][2]string{
-	}
+		{paxPath + "=/etc/hosts", "19 path=/etc/hosts\n"},
-	hdr, err := FileInfoHeader(fileinfo, "")
+		{"a=b", "6 a=b\n"},          // Single digit length
-	if err != nil {
+		{"a=names", "11 a=names\n"}, // Test case involving carries
-		t.Fatalf("os.Stat: %v", err)
+		{paxPath + "=" + longName, fmt.Sprintf("210 path=%s\n", longName)},
-	}
+		{paxPath + "=" + medName, fmt.Sprintf("110 path=%s\n", medName)}}
-	contents := strings.Repeat(" ", int(hdr.Size))
 
-	hdr.Xattrs = map[string]string{
+	for _, test := range paxTests {
-		"foo": "foo",
+		key, expected := test[0], test[1]
-		"bar": "bar",
+		if result := paxHeader(key); result != expected {
-		"baz": "baz",
+			t.Fatalf("paxHeader: got %s, expected %s", result, expected)
-		"qux": "qux",
+		}
-	}
-
-	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)
-	}
-	// Simple test to make sure PAX extensions are in effect
-	if !bytes.Contains(buf.Bytes(), []byte("PaxHeaders.0")) {
-		t.Fatal("Expected at least one PAX header to be written.")
-	}
-
-	// xattr bar should always appear before others
-	indices := []int{
-		bytes.Index(buf.Bytes(), []byte("bar=bar")),
-		bytes.Index(buf.Bytes(), []byte("baz=baz")),
-		bytes.Index(buf.Bytes(), []byte("foo=foo")),
-		bytes.Index(buf.Bytes(), []byte("qux=qux")),
-	}
-	if !sort.IntsAreSorted(indices) {
-		t.Fatal("PAX headers are not sorted")
 	}
 }
 
@@ -574,149 +544,3 @@ func TestWriteAfterClose(t *testing.T) {
 		t.Fatalf("Write: got %v; want ErrWriteAfterClose", err)
 	}
 }
-
-func TestSplitUSTARPath(t *testing.T) {
-	var sr = strings.Repeat
-
-	var vectors = []struct {
-		input  string // Input path
-		prefix string // Expected output prefix
-		suffix string // Expected output suffix
-		ok     bool   // Split success?
-	}{
-		{"", "", "", false},
-		{"abc", "", "", false},
-		{"用戶名", "", "", false},
-		{sr("a", fileNameSize), "", "", false},
-		{sr("a", fileNameSize) + "/", "", "", false},
-		{sr("a", fileNameSize) + "/a", sr("a", fileNameSize), "a", true},
-		{sr("a", fileNamePrefixSize) + "/", "", "", false},
-		{sr("a", fileNamePrefixSize) + "/a", sr("a", fileNamePrefixSize), "a", true},
-		{sr("a", fileNameSize+1), "", "", false},
-		{sr("/", fileNameSize+1), sr("/", fileNameSize-1), "/", true},
-		{sr("a", fileNamePrefixSize) + "/" + sr("b", fileNameSize),
-			sr("a", fileNamePrefixSize), sr("b", fileNameSize), true},
-		{sr("a", fileNamePrefixSize) + "//" + sr("b", fileNameSize), "", "", false},
-		{sr("a/", fileNameSize), sr("a/", 77) + "a", sr("a/", 22), true},
-	}
-
-	for _, v := range vectors {
-		prefix, suffix, ok := splitUSTARPath(v.input)
-		if prefix != v.prefix || suffix != v.suffix || ok != v.ok {
-			t.Errorf("splitUSTARPath(%q):\ngot  (%q, %q, %v)\nwant (%q, %q, %v)",
-				v.input, prefix, suffix, ok, v.prefix, v.suffix, v.ok)
-		}
-	}
-}
-
-func TestFormatPAXRecord(t *testing.T) {
-	var medName = strings.Repeat("CD", 50)
-	var longName = strings.Repeat("AB", 100)
-
-	var vectors = []struct {
-		inputKey string
-		inputVal string
-		output   string
-	}{
-		{"k", "v", "6 k=v\n"},
-		{"path", "/etc/hosts", "19 path=/etc/hosts\n"},
-		{"path", longName, "210 path=" + longName + "\n"},
-		{"path", medName, "110 path=" + medName + "\n"},
-		{"foo", "ba", "9 foo=ba\n"},
-		{"foo", "bar", "11 foo=bar\n"},
-		{"foo", "b=\nar=\n==\x00", "18 foo=b=\nar=\n==\x00\n"},
-		{"foo", "hello9 foo=ba\nworld", "27 foo=hello9 foo=ba\nworld\n"},
-		{"☺☻☹", "日a本b語ç", "27 ☺☻☹=日a本b語ç\n"},
-		{"\x00hello", "\x00world", "17 \x00hello=\x00world\n"},
-	}
-
-	for _, v := range vectors {
-		output := formatPAXRecord(v.inputKey, v.inputVal)
-		if output != v.output {
-			t.Errorf("formatPAXRecord(%q, %q): got %q, want %q",
-				v.inputKey, v.inputVal, output, v.output)
-		}
-	}
-}
-
-func TestFitsInBase256(t *testing.T) {
-	var vectors = []struct {
-		input int64
-		width int
-		ok    bool
-	}{
-		{+1, 8, true},
-		{0, 8, true},
-		{-1, 8, true},
-		{1 << 56, 8, false},
-		{(1 << 56) - 1, 8, true},
-		{-1 << 56, 8, true},
-		{(-1 << 56) - 1, 8, false},
-		{121654, 8, true},
-		{-9849849, 8, true},
-		{math.MaxInt64, 9, true},
-		{0, 9, true},
-		{math.MinInt64, 9, true},
-		{math.MaxInt64, 12, true},
-		{0, 12, true},
-		{math.MinInt64, 12, true},
-	}
-
-	for _, v := range vectors {
-		ok := fitsInBase256(v.width, v.input)
-		if ok != v.ok {
-			t.Errorf("checkNumeric(%d, %d): got %v, want %v", v.input, v.width, ok, v.ok)
-		}
-	}
-}
-
-func TestFormatNumeric(t *testing.T) {
-	var vectors = []struct {
-		input  int64
-		output string
-		ok     bool
-	}{
-		// Test base-256 (binary) encoded values.
-		{-1, "\xff", true},
-		{-1, "\xff\xff", true},
-		{-1, "\xff\xff\xff", true},
-		{(1 << 0), "0", false},
-		{(1 << 8) - 1, "\x80\xff", true},
-		{(1 << 8), "0\x00", false},
-		{(1 << 16) - 1, "\x80\xff\xff", true},
-		{(1 << 16), "00\x00", false},
-		{-1 * (1 << 0), "\xff", true},
-		{-1*(1<<0) - 1, "0", false},
-		{-1 * (1 << 8), "\xff\x00", true},
-		{-1*(1<<8) - 1, "0\x00", false},
-		{-1 * (1 << 16), "\xff\x00\x00", true},
-		{-1*(1<<16) - 1, "00\x00", false},
-		{537795476381659745, "0000000\x00", false},
-		{537795476381659745, "\x80\x00\x00\x00\x07\x76\xa2\x22\xeb\x8a\x72\x61", true},
-		{-615126028225187231, "0000000\x00", false},
-		{-615126028225187231, "\xff\xff\xff\xff\xf7\x76\xa2\x22\xeb\x8a\x72\x61", true},
-		{math.MaxInt64, "0000000\x00", false},
-		{math.MaxInt64, "\x80\x00\x00\x00\x7f\xff\xff\xff\xff\xff\xff\xff", true},
-		{math.MinInt64, "0000000\x00", false},
-		{math.MinInt64, "\xff\xff\xff\xff\x80\x00\x00\x00\x00\x00\x00\x00", true},
-		{math.MaxInt64, "\x80\x7f\xff\xff\xff\xff\xff\xff\xff", true},
-		{math.MinInt64, "\xff\x80\x00\x00\x00\x00\x00\x00\x00", true},
-	}
-
-	for _, v := range vectors {
-		var f formatter
-		output := make([]byte, len(v.output))
-		f.formatNumeric(output, v.input)
-		ok := (f.err == nil)
-		if ok != v.ok {
-			if v.ok {
-				t.Errorf("formatNumeric(%d): got formatting failure, want success", v.input)
-			} else {
-				t.Errorf("formatNumeric(%d): got formatting success, want failure", v.input)
-			}
-		}
-		if string(output) != v.output {
-			t.Errorf("formatNumeric(%d): got %q, want %q", v.input, output, v.output)
-		}
-	}
-}

cmd/tar-split/asm.go

@@ -6,7 +6,7 @@ import (
 	"os"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/urfave/cli"
+	"github.com/codegangsta/cli"
 	"github.com/vbatts/tar-split/tar/asm"
 	"github.com/vbatts/tar-split/tar/storage"
 )

cmd/tar-split/checksize.go

@@ -10,7 +10,7 @@ import (
 	"os"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/urfave/cli"
+	"github.com/codegangsta/cli"
 	"github.com/vbatts/tar-split/tar/asm"
 	"github.com/vbatts/tar-split/tar/storage"
 )

cmd/tar-split/disasm.go

@@ -3,11 +3,10 @@ package main
 import (
 	"compress/gzip"
 	"io"
-	"io/ioutil"
 	"os"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/urfave/cli"
+	"github.com/codegangsta/cli"
 	"github.com/vbatts/tar-split/tar/asm"
 	"github.com/vbatts/tar-split/tar/storage"
 )
@@ -49,13 +48,7 @@ func CommandDisasm(c *cli.Context) {
 	if err != nil {
 		logrus.Fatal(err)
 	}
-	var out io.Writer
+	i, err := io.Copy(os.Stdout, its)
-	if c.Bool("no-stdout") {
-		out = ioutil.Discard
-	} else {
-		out = os.Stdout
-	}
-	i, err := io.Copy(out, its)
 	if err != nil {
 		logrus.Fatal(err)
 	}

cmd/tar-split/main.go

@@ -4,7 +4,7 @@ import (
 	"os"
 
 	"github.com/Sirupsen/logrus"
-	"github.com/urfave/cli"
+	"github.com/codegangsta/cli"
 	"github.com/vbatts/tar-split/version"
 )
 
@@ -42,10 +42,6 @@ func main() {
 					Value: "tar-data.json.gz",
 					Usage: "output of disassembled tar stream",
 				},
-				cli.BoolFlag{
-					Name:  "no-stdout",
-					Usage: "do not throughput the stream to STDOUT",
-				},
 			},
 		},
 		{

tar/asm/assemble.go

@@ -3,10 +3,8 @@ package asm
 import (
 	"bytes"
 	"fmt"
-	"hash"
 	"hash/crc64"
 	"io"
-	"sync"
 
 	"github.com/vbatts/tar-split/tar/storage"
 )
@@ -25,106 +23,45 @@ func NewOutputTarStream(fg storage.FileGetter, up storage.Unpacker) io.ReadClose
 	}
 	pr, pw := io.Pipe()
 	go func() {
-		err := WriteOutputTarStream(fg, up, pw)
+		for {
-		if err != nil {
+			entry, err := up.Next()
-			pw.CloseWithError(err)
+			if err != nil {
-		} else {
+				pw.CloseWithError(err)
-			pw.Close()
+				return
+			}
+			switch entry.Type {
+			case storage.SegmentType:
+				if _, err := pw.Write(entry.Payload); err != nil {
+					pw.CloseWithError(err)
+					return
+				}
+			case storage.FileType:
+				if entry.Size == 0 {
+					continue
+				}
+				fh, err := fg.Get(entry.GetName())
+				if err != nil {
+					pw.CloseWithError(err)
+					return
+				}
+				c := crc64.New(storage.CRCTable)
+				tRdr := io.TeeReader(fh, c)
+				if _, err := io.Copy(pw, tRdr); err != nil {
+					fh.Close()
+					pw.CloseWithError(err)
+					return
+				}
+				if !bytes.Equal(c.Sum(nil), entry.Payload) {
+					// I would rather this be a comparable ErrInvalidChecksum or such,
+					// but since it's coming through the PipeReader, the context of
+					// _which_ file would be lost...
+					fh.Close()
+					pw.CloseWithError(fmt.Errorf("file integrity checksum failed for %q", entry.GetName()))
+					return
+				}
+				fh.Close()
+			}
 		}
 	}()
 	return pr
 }
-
-// WriteOutputTarStream writes assembled tar archive to a writer.
-func WriteOutputTarStream(fg storage.FileGetter, up storage.Unpacker, w io.Writer) error {
-	// ... Since these are interfaces, this is possible, so let's not have a nil pointer
-	if fg == nil || up == nil {
-		return nil
-	}
-	var copyBuffer []byte
-	var crcHash hash.Hash
-	var crcSum []byte
-	var multiWriter io.Writer
-	for {
-		entry, err := up.Next()
-		if err != nil {
-			if err == io.EOF {
-				return nil
-			}
-			return err
-		}
-		switch entry.Type {
-		case storage.SegmentType:
-			if _, err := w.Write(entry.Payload); err != nil {
-				return err
-			}
-		case storage.FileType:
-			if entry.Size == 0 {
-				continue
-			}
-			fh, err := fg.Get(entry.GetName())
-			if err != nil {
-				return err
-			}
-			if crcHash == nil {
-				crcHash = crc64.New(storage.CRCTable)
-				crcSum = make([]byte, 8)
-				multiWriter = io.MultiWriter(w, crcHash)
-				copyBuffer = byteBufferPool.Get().([]byte)
-				defer byteBufferPool.Put(copyBuffer)
-			} else {
-				crcHash.Reset()
-			}
-
-			if _, err := copyWithBuffer(multiWriter, fh, copyBuffer); err != nil {
-				fh.Close()
-				return err
-			}
-
-			if !bytes.Equal(crcHash.Sum(crcSum[:0]), entry.Payload) {
-				// I would rather this be a comparable ErrInvalidChecksum or such,
-				// but since it's coming through the PipeReader, the context of
-				// _which_ file would be lost...
-				fh.Close()
-				return fmt.Errorf("file integrity checksum failed for %q", entry.GetName())
-			}
-			fh.Close()
-		}
-	}
-}
-
-var byteBufferPool = &sync.Pool{
-	New: func() interface{} {
-		return make([]byte, 32*1024)
-	},
-}
-
-// copyWithBuffer is taken from stdlib io.Copy implementation
-// https://github.com/golang/go/blob/go1.5.1/src/io/io.go#L367
-func copyWithBuffer(dst io.Writer, src io.Reader, buf []byte) (written int64, err error) {
-	for {
-		nr, er := src.Read(buf)
-		if nr > 0 {
-			nw, ew := dst.Write(buf[0:nr])
-			if nw > 0 {
-				written += int64(nw)
-			}
-			if ew != nil {
-				err = ew
-				break
-			}
-			if nr != nw {
-				err = io.ErrShortWrite
-				break
-			}
-		}
-		if er == io.EOF {
-			break
-		}
-		if er != nil {
-			err = er
-			break
-		}
-	}
-	return written, err
-}

tar/asm/assemble_test.go

@@ -130,20 +130,17 @@ func TestTarStreamMangledGetterPutter(t *testing.T) {
 	}
 }
 
-var testCases = []struct {
-	path            string
-	expectedSHA1Sum string
-	expectedSize    int64
-}{
-	{"./testdata/t.tar.gz", "1eb237ff69bca6e22789ecb05b45d35ca307adbd", 10240},
-	{"./testdata/longlink.tar.gz", "d9f6babe107b7247953dff6b5b5ae31a3a880add", 20480},
-	{"./testdata/fatlonglink.tar.gz", "8537f03f89aeef537382f8b0bb065d93e03b0be8", 26234880},
-	{"./testdata/iso-8859.tar.gz", "ddafa51cb03c74ec117ab366ee2240d13bba1ec3", 10240},
-	{"./testdata/extranils.tar.gz", "e187b4b3e739deaccc257342f4940f34403dc588", 10648},
-	{"./testdata/notenoughnils.tar.gz", "72f93f41efd95290baa5c174c234f5d4c22ce601", 512},
-}
-
 func TestTarStream(t *testing.T) {
+	testCases := []struct {
+		path            string
+		expectedSHA1Sum string
+		expectedSize    int64
+	}{
+		{"./testdata/t.tar.gz", "1eb237ff69bca6e22789ecb05b45d35ca307adbd", 10240},
+		{"./testdata/longlink.tar.gz", "d9f6babe107b7247953dff6b5b5ae31a3a880add", 20480},
+		{"./testdata/fatlonglink.tar.gz", "8537f03f89aeef537382f8b0bb065d93e03b0be8", 26234880},
+		{"./testdata/iso-8859.tar.gz", "ddafa51cb03c74ec117ab366ee2240d13bba1ec3", 10240},
+	}
 
 	for _, tc := range testCases {
 		fh, err := os.Open(tc.path)
@@ -170,7 +167,10 @@ func TestTarStream(t *testing.T) {
 
 		// get a sum of the stream after it has passed through to ensure it's the same.
 		h0 := sha1.New()
-		i, err := io.Copy(h0, tarStream)
+		tRdr0 := io.TeeReader(tarStream, h0)
+
+		// read it all to the bit bucket
+		i, err := io.Copy(ioutil.Discard, tRdr0)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -205,52 +205,3 @@ func TestTarStream(t *testing.T) {
 		}
 	}
 }
-
-func BenchmarkAsm(b *testing.B) {
-	for i := 0; i < b.N; i++ {
-		for _, tc := range testCases {
-			func() {
-				fh, err := os.Open(tc.path)
-				if err != nil {
-					b.Fatal(err)
-				}
-				defer fh.Close()
-				gzRdr, err := gzip.NewReader(fh)
-				if err != nil {
-					b.Fatal(err)
-				}
-				defer gzRdr.Close()
-
-				// Setup where we'll store the metadata
-				w := bytes.NewBuffer([]byte{})
-				sp := storage.NewJSONPacker(w)
-				fgp := storage.NewBufferFileGetPutter()
-
-				// wrap the disassembly stream
-				tarStream, err := NewInputTarStream(gzRdr, sp, fgp)
-				if err != nil {
-					b.Fatal(err)
-				}
-				// read it all to the bit bucket
-				i1, err := io.Copy(ioutil.Discard, tarStream)
-				if err != nil {
-					b.Fatal(err)
-				}
-
-				r := bytes.NewBuffer(w.Bytes())
-				sup := storage.NewJSONUnpacker(r)
-				// and reuse the fgp that we Put the payloads to.
-
-				rc := NewOutputTarStream(fgp, sup)
-
-				i2, err := io.Copy(ioutil.Discard, rc)
-				if err != nil {
-					b.Fatal(err)
-				}
-				if i1 != i2 {
-					b.Errorf("%s: input(%d) and ouput(%d) byte count didn't match", tc.path, i1, i2)
-				}
-			}()
-		}
-	}
-}

tar/storage/packer.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"bufio"
 	"encoding/json"
 	"errors"
 	"io"
@@ -32,15 +33,31 @@ type PackUnpacker interface {
 */
 
 type jsonUnpacker struct {
-	seen seenNames
+	r     io.Reader
-	dec  *json.Decoder
+	b     *bufio.Reader
+	isEOF bool
+	seen  seenNames
 }
 
 func (jup *jsonUnpacker) Next() (*Entry, error) {
 	var e Entry
-	err := jup.dec.Decode(&e)
+	if jup.isEOF {
-	if err != nil {
+		// since ReadBytes() will return read bytes AND an EOF, we handle it this
+		// round-a-bout way so we can Unmarshal the tail with relevant errors, but
+		// still get an io.EOF when the stream is ended.
+		return nil, io.EOF
+	}
+	line, err := jup.b.ReadBytes('\n')
+	if err != nil && err != io.EOF {
 		return nil, err
+	} else if err == io.EOF {
+		jup.isEOF = true
+	}
+
+	err = json.Unmarshal(line, &e)
+	if err != nil && jup.isEOF {
+		// if the remainder actually _wasn't_ a remaining json structure, then just EOF
+		return nil, io.EOF
 	}
 
 	// check for dup name
@@ -61,7 +78,8 @@ func (jup *jsonUnpacker) Next() (*Entry, error) {
 // Each Entry read are expected to be delimited by new line.
 func NewJSONUnpacker(r io.Reader) Unpacker {
 	return &jsonUnpacker{
-		dec:  json.NewDecoder(r),
+		r:    r,
+		b:    bufio.NewReader(r),
 		seen: seenNames{},
 	}
 }

tar/storage/packer_test.go

@@ -4,8 +4,6 @@ import (
 	"bytes"
 	"compress/gzip"
 	"io"
-	"io/ioutil"
-	"os"
 	"testing"
 )
 
@@ -161,58 +159,5 @@ func TestGzip(t *testing.T) {
 	if len(entries) != len(e) {
 		t.Errorf("expected %d entries, got %d", len(e), len(entries))
 	}
-}
+
-
-func BenchmarkGetPut(b *testing.B) {
-	e := []Entry{
-		Entry{
-			Type:    SegmentType,
-			Payload: []byte("how"),
-		},
-		Entry{
-			Type:    SegmentType,
-			Payload: []byte("y'all"),
-		},
-		Entry{
-			Type:    FileType,
-			Name:    "./hurr.txt",
-			Payload: []byte("deadbeef"),
-		},
-		Entry{
-			Type:    SegmentType,
-			Payload: []byte("doin"),
-		},
-	}
-	b.RunParallel(func(pb *testing.PB) {
-		for pb.Next() {
-			func() {
-				fh, err := ioutil.TempFile("", "tar-split.")
-				if err != nil {
-					b.Fatal(err)
-				}
-				defer os.Remove(fh.Name())
-				defer fh.Close()
-
-				jp := NewJSONPacker(fh)
-				for i := range e {
-					if _, err := jp.AddEntry(e[i]); err != nil {
-						b.Fatal(err)
-					}
-				}
-				fh.Sync()
-
-				up := NewJSONUnpacker(fh)
-				for {
-					_, err := up.Next()
-					if err != nil {
-						if err == io.EOF {
-							break
-						}
-						b.Fatal(err)
-					}
-				}
-
-			}()
-		}
-	})
 }

tar_benchmark_test.go

@@ -1,84 +0,0 @@
-package tartest
-
-import (
-	"io"
-	"io/ioutil"
-	"os"
-	"testing"
-
-	upTar "archive/tar"
-
-	ourTar "github.com/vbatts/tar-split/archive/tar"
-)
-
-var testfile = "./archive/tar/testdata/sparse-formats.tar"
-
-func BenchmarkUpstreamTar(b *testing.B) {
-	for n := 0; n < b.N; n++ {
-		fh, err := os.Open(testfile)
-		if err != nil {
-			b.Fatal(err)
-		}
-		tr := upTar.NewReader(fh)
-		for {
-			_, err := tr.Next()
-			if err != nil {
-				if err == io.EOF {
-					break
-				}
-				fh.Close()
-				b.Fatal(err)
-			}
-			io.Copy(ioutil.Discard, tr)
-		}
-		fh.Close()
-	}
-}
-
-func BenchmarkOurTarNoAccounting(b *testing.B) {
-	for n := 0; n < b.N; n++ {
-		fh, err := os.Open(testfile)
-		if err != nil {
-			b.Fatal(err)
-		}
-		tr := ourTar.NewReader(fh)
-		tr.RawAccounting = false // this is default, but explicit here
-		for {
-			_, err := tr.Next()
-			if err != nil {
-				if err == io.EOF {
-					break
-				}
-				fh.Close()
-				b.Fatal(err)
-			}
-			io.Copy(ioutil.Discard, tr)
-		}
-		fh.Close()
-	}
-}
-func BenchmarkOurTarYesAccounting(b *testing.B) {
-	for n := 0; n < b.N; n++ {
-		fh, err := os.Open(testfile)
-		if err != nil {
-			b.Fatal(err)
-		}
-		tr := ourTar.NewReader(fh)
-		tr.RawAccounting = true // This enables mechanics for collecting raw bytes
-		for {
-			_ = tr.RawBytes()
-			_, err := tr.Next()
-			_ = tr.RawBytes()
-			if err != nil {
-				if err == io.EOF {
-					break
-				}
-				fh.Close()
-				b.Fatal(err)
-			}
-			io.Copy(ioutil.Discard, tr)
-			_ = tr.RawBytes()
-		}
-		fh.Close()
-	}
-}

version/version.go

@@ -1,7 +1,7 @@
 package version
-
 // AUTO-GENEREATED. DO NOT EDIT
-// 2016-09-26 19:53:30.825879 -0400 EDT
+// 2015-08-14 09:56:50.742727493 -0400 EDT
 
 // VERSION is the generated version from /home/vbatts/src/vb/tar-split/version
-var VERSION = "v0.10.1-4-gf280282"
+var VERSION = "v0.9.6-1-gc76e420"
+