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Merge pull request #26932 from dmcgowan/update-tar-split

Browse source 
Update tar split
This commit is contained in:
Alexander Morozov 2016-10-05 13:45:07 -07:00 committed by GitHub
commit 921a0bf686
5 changed files with 580 additions and 419 deletions
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2
hack/vendor.sh
View file

@ -92,7 +92,7 @@ clone git github.com/miekg/dns 75e6e86cc601825c5dbcd4e0c209eab180997cd7
# get graph and distribution packages
clone git github.com/docker/distribution 77b9d2997abcded79a5314970fe69a44c93c25fb
clone git github.com/vbatts/tar-split v0.9.11
clone git github.com/vbatts/tar-split v0.10.1
# get go-zfs packages
clone git github.com/mistifyio/go-zfs 22c9b32c84eb0d0c6f4043b6e90fc94073de92fa

39
vendor/src/github.com/vbatts/tar-split/LICENSE vendored
View file

@ -1,19 +1,28 @@
Copyright (c) 2015 Vincent Batts, Raleigh, NC, USA
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:
All rights reserved.
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
1. Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
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.

11
vendor/src/github.com/vbatts/tar-split/archive/tar/common.go vendored
View file

@ -327,3 +327,14 @@ 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
}
}

725
vendor/src/github.com/vbatts/tar-split/archive/tar/reader.go vendored
View file

@ -12,6 +12,7 @@ import (
"errors"
"io"
"io/ioutil"
"math"
"os"
"strconv"
"strings"
@ -39,6 +40,10 @@ 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.
//
@ -70,12 +75,36 @@ 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 tar archive.
// A sparseFileReader is a numBytesReader for reading sparse file data from a
// tar archive.
type sparseFileReader struct {
rfr *regFileReader // reads the sparse-encoded file data
sp []sparseEntry // the sparse map for the file
pos int64 // keeps track of file position
tot int64 // total size of the file
rfr numBytesReader // Reads the sparse-encoded file data
sp []sparseEntry // The sparse map for the file
pos int64 // Keeps track of file position
total 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
@ -109,7 +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 hdr *Header
if tr.RawAccounting {
if tr.rawBytes == nil {
tr.rawBytes = bytes.NewBuffer(nil)
@ -117,98 +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 PAX/GNU special headers and files.
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
}
// 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 {
// Current file is a PAX format GNU sparse file.
// Set the current file reader to a sparse file reader.
tr.curr = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
}
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 {
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 = 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, tr.err
return hdr, nil
}
// checkForGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers. If they are found, then
@ -385,6 +403,7 @@ 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.
@ -393,35 +412,17 @@ 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(buf) > 0 {
// or the header was empty to start with.
var sp int
// The size field ends at the first space.
sp = bytes.IndexByte(buf, ' ')
if sp == -1 {
for len(sbuf) > 0 {
key, value, residual, err := parsePAXRecord(sbuf)
if err != nil {
return nil, ErrHeader
}
// 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:]
sbuf = residual
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.Write(value)
sparseMap.WriteString(value)
sparseMap.Write([]byte{','})
} else {
// Normal key. Set the value in the headers map.
@ -436,9 +437,42 @@ func parsePAX(r io.Reader) (map[string]string, error) {
return headers, nil
}
// cString parses bytes as a NUL-terminated C-style string.
// parsePAXRecord parses the input PAX record string into a key-value pair.
// 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 cString(b []byte) string {
func (*parser) parseString(b []byte) string {
n := 0
for n < len(b) && b[n] != 0 {
n++
@ -446,19 +480,51 @@ func cString(b []byte) string {
return string(b[0:n])
}
func (tr *Reader) octal(b []byte) int64 {
// Check for binary format first.
// parseNumeric parses the input as being encoded in either base-256 or octal.
// This function may return negative numbers.
// 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 {
var x int64
for i, c := range b {
if i == 0 {
c &= 0x7f // ignore signal bit in first byte
}
x = x<<8 | int64(c)
// Handling negative numbers relies on the following identity:
// -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
}
return x
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
}
if (x >> 56) > 0 {
p.err = ErrHeader // Integer overflow
return 0
}
x = x<<8 | uint64(c)
}
if (x >> 63) > 0 {
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.
@ -469,27 +535,55 @@ func (tr *Reader) octal(b []byte) int64 {
if len(b) == 0 {
return 0
}
x, err := strconv.ParseUint(cString(b), 8, 64)
if err != nil {
tr.err = err
x, perr := strconv.ParseUint(p.parseString(b), 8, 64)
if perr != nil {
p.err = ErrHeader
}
return int64(x)
}
// skipUnread skips any unread bytes in the existing file entry, as well as any alignment padding.
func (tr *Reader) skipUnread() {
nr := tr.numBytes() + tr.pad // number of bytes to skip
// skipUnread skips any unread bytes in the existing file entry, as well as any
// alignment padding. It returns io.ErrUnexpectedEOF if any io.EOF is
// encountered in the data portion; it is okay to hit io.EOF in the padding.
//
// 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, nr)
return
_, tr.err = io.CopyN(tr.rawBytes, tr.r, totalSkip)
return tr.err
}
if sr, ok := tr.r.(io.Seeker); ok {
if _, err := sr.Seek(nr, os.SEEK_CUR); err == nil {
return
// If possible, Seek to the last byte before the end of the data section.
// Do this because Seek is often lazy about reporting errors; this will mask
// the fact that the tar stream may be truncated. We can rely on the
// 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 {
@ -497,23 +591,32 @@ func (tr *Reader) verifyChecksum(header []byte) bool {
return false
}
given := tr.octal(header[148:156])
var p parser
given := p.parseOctal(header[148:156])
unsigned, signed := checksum(header)
return given == unsigned || given == signed
return p.err == nil && (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 _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
if n, err := io.ReadFull(tr.r, header); 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 _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
return nil
if _, err := tr.rawBytes.Write(header[:n]); err != nil {
tr.err = err
}
}
return nil
return nil // io.EOF is okay here
}
if tr.RawAccounting {
if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
@ -523,14 +626,15 @@ func (tr *Reader) readHeader() *Header {
// Two blocks of zero bytes marks the end of the archive.
if bytes.Equal(header, zeroBlock[0:blockSize]) {
if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
if n, err := io.ReadFull(tr.r, header); 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 _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
return nil
if _, err := tr.rawBytes.Write(header[:n]); err != nil {
tr.err = err
}
}
return nil
return nil // io.EOF is okay here
}
if tr.RawAccounting {
if _, tr.err = tr.rawBytes.Write(header); tr.err != nil {
@ -551,22 +655,19 @@ func (tr *Reader) readHeader() *Header {
}
// Unpack
var p parser
hdr := new(Header)
s := slicer(header)
hdr.Name = cString(s.next(100))
hdr.Mode = tr.octal(s.next(8))
hdr.Uid = int(tr.octal(s.next(8)))
hdr.Gid = int(tr.octal(s.next(8)))
hdr.Size = tr.octal(s.next(12))
if hdr.Size < 0 {
tr.err = ErrHeader
return nil
}
hdr.ModTime = time.Unix(tr.octal(s.next(12)), 0)
hdr.Name = p.parseString(s.next(100))
hdr.Mode = p.parseNumeric(s.next(8))
hdr.Uid = int(p.parseNumeric(s.next(8)))
hdr.Gid = int(p.parseNumeric(s.next(8)))
hdr.Size = p.parseNumeric(s.next(12))
hdr.ModTime = time.Unix(p.parseNumeric(s.next(12)), 0)
s.next(8) // chksum
hdr.Typeflag = s.next(1)[0]
hdr.Linkname = cString(s.next(100))
hdr.Linkname = p.parseString(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,
@ -586,70 +687,76 @@ func (tr *Reader) readHeader() *Header {
switch format {
case "posix", "gnu", "star":
hdr.Uname = cString(s.next(32))
hdr.Gname = cString(s.next(32))
hdr.Uname = p.parseString(s.next(32))
hdr.Gname = p.parseString(s.next(32))
devmajor := s.next(8)
devminor := s.next(8)
if hdr.Typeflag == TypeChar || hdr.Typeflag == TypeBlock {
hdr.Devmajor = tr.octal(devmajor)
hdr.Devminor = tr.octal(devminor)
hdr.Devmajor = p.parseNumeric(devmajor)
hdr.Devminor = p.parseNumeric(devminor)
}
var prefix string
switch format {
case "posix", "gnu":
prefix = cString(s.next(155))
prefix = p.parseString(s.next(155))
case "star":
prefix = cString(s.next(131))
hdr.AccessTime = time.Unix(tr.octal(s.next(12)), 0)
hdr.ChangeTime = time.Unix(tr.octal(s.next(12)), 0)
prefix = p.parseString(s.next(131))
hdr.AccessTime = time.Unix(p.parseNumeric(s.next(12)), 0)
hdr.ChangeTime = time.Unix(p.parseNumeric(s.next(12)), 0)
}
if len(prefix) > 0 {
hdr.Name = prefix + "/" + hdr.Name
}
}
if tr.err != nil {
if p.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
}
// 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.pad = -nb & (blockSize - 1) // blockSize is a power of two
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 = tr.octal(header[483:495])
hdr.Size = p.parseNumeric(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 = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
tr.curr, tr.err = newSparseFileReader(tr.curr, sp, 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 {
@ -660,10 +767,10 @@ func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
// Read the four entries from the main tar header
for i := 0; i < oldGNUSparseMainHeaderNumEntries; i++ {
offset := tr.octal(s.next(oldGNUSparseOffsetSize))
numBytes := tr.octal(s.next(oldGNUSparseNumBytesSize))
if tr.err != nil {
tr.err = ErrHeader
offset := p.parseNumeric(s.next(oldGNUSparseOffsetSize))
numBytes := p.parseNumeric(s.next(oldGNUSparseNumBytesSize))
if p.err != nil {
tr.err = p.err
return nil
}
if offset == 0 && numBytes == 0 {
@ -687,10 +794,10 @@ func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
isExtended = sparseHeader[oldGNUSparseExtendedHeaderIsExtendedOffset] != 0
s = slicer(sparseHeader)
for i := 0; i < oldGNUSparseExtendedHeaderNumEntries; i++ {
offset := tr.octal(s.next(oldGNUSparseOffsetSize))
numBytes := tr.octal(s.next(oldGNUSparseNumBytesSize))
if tr.err != nil {
tr.err = ErrHeader
offset := p.parseNumeric(s.next(oldGNUSparseOffsetSize))
numBytes := p.parseNumeric(s.next(oldGNUSparseNumBytesSize))
if p.err != nil {
tr.err = p.err
return nil
}
if offset == 0 && numBytes == 0 {
@ -702,134 +809,111 @@ func (tr *Reader) readOldGNUSparseMap(header []byte) []sparseEntry {
return sp
}
// readGNUSparseMap1x0 reads the sparse map as stored in GNU's PAX sparse format version 1.0.
// The sparse map is stored just before the file data and padded out to the nearest block boundary.
// readGNUSparseMap1x0 reads the sparse map as stored in GNU's PAX sparse format
// version 1.0. The format of the sparse map consists of a series of
// 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) {
buf := make([]byte, 2*blockSize)
sparseHeader := buf[:blockSize]
var cntNewline int64
var buf bytes.Buffer
var blk = make([]byte, blockSize)
// readDecimal is a helper function to read a decimal integer from the sparse map
// while making sure to read from the file in blocks of size blockSize
readDecimal := func() (int64, error) {
// Look for newline
nl := bytes.IndexByte(sparseHeader, '\n')
if nl == -1 {
if len(sparseHeader) >= blockSize {
// This is an error
return 0, ErrHeader
// feedTokens copies data in numBlock chunks from r into buf until there are
// at least cnt newlines in buf. It will not read more blocks than needed.
var feedTokens = func(cnt int64) error {
for cntNewline < cnt {
if _, err := io.ReadFull(r, blk); err != nil {
if err == io.EOF {
err = io.ErrUnexpectedEOF
}
return err
}
oldLen := len(sparseHeader)
newLen := oldLen + blockSize
if cap(sparseHeader) < newLen {
// 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
buf.Write(blk)
for _, c := range blk {
if c == '\n' {
cntNewline++
}
}
// 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
}
// 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
return nil
}
// Read the first block
if _, err := io.ReadFull(r, sparseHeader); err != nil {
// nextToken gets the next token delimited by a newline. This assumes that
// at least one newline exists in the buffer.
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
}
// leaving this function for io.Reader makes it more testable
if tr, ok := r.(*Reader); ok && tr.RawAccounting {
if _, err := tr.rawBytes.Write(sparseHeader); err != nil {
return nil, err
}
numEntries, err := strconv.ParseInt(nextToken(), 10, 0) // Intentionally parse as native int
if err != nil || numEntries < 0 || int(2*numEntries) < int(numEntries) {
return nil, ErrHeader
}
// The first line contains the number of entries
numEntries, err := readDecimal()
if err != nil {
// Parse for all member entries.
// numEntries is trusted after this since a potential attacker must have
// committed resources proportional to what this library used.
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++ {
// Read the offset
offset, err := readDecimal()
offset, err := strconv.ParseInt(nextToken(), 10, 64)
if err != nil {
return nil, err
return nil, ErrHeader
}
// Read numBytes
numBytes, err := readDecimal()
numBytes, err := strconv.ParseInt(nextToken(), 10, 64)
if err != nil {
return nil, err
return nil, ErrHeader
}
sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
}
return sp, nil
}
// readGNUSparseMap0x1 reads the sparse map as stored in GNU's PAX sparse format version 0.1.
// The sparse map is stored in the PAX headers.
func readGNUSparseMap0x1(headers map[string]string) ([]sparseEntry, error) {
// Get number of entries
numEntriesStr, ok := headers[paxGNUSparseNumBlocks]
if !ok {
return nil, ErrHeader
}
numEntries, err := strconv.ParseInt(numEntriesStr, 10, 0)
if err != nil {
// readGNUSparseMap0x1 reads the sparse map as stored in GNU's PAX sparse format
// version 0.1. The sparse map is stored in the PAX headers.
func readGNUSparseMap0x1(extHdrs map[string]string) ([]sparseEntry, error) {
// Get number of entries.
// Use integer overflow resistant math to check this.
numEntriesStr := extHdrs[paxGNUSparseNumBlocks]
numEntries, err := strconv.ParseInt(numEntriesStr, 10, 0) // Intentionally parse as native int
if err != nil || numEntries < 0 || int(2*numEntries) < int(numEntries) {
return nil, ErrHeader
}
sparseMap := strings.Split(headers[paxGNUSparseMap], ",")
// There should be two numbers in sparseMap for each entry
// There should be two numbers in sparseMap for each entry.
sparseMap := strings.Split(extHdrs[paxGNUSparseMap], ",")
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, 0)
offset, err := strconv.ParseInt(sparseMap[2*i], 10, 64)
if err != nil {
return nil, ErrHeader
}
numBytes, err := strconv.ParseInt(sparseMap[2*i+1], 10, 0)
numBytes, err := strconv.ParseInt(sparseMap[2*i+1], 10, 64)
if err != nil {
return nil, ErrHeader
}
sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
}
return sp, nil
}
@ -846,10 +930,18 @@ 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
@ -879,9 +971,33 @@ func (rfr *regFileReader) numBytes() int64 {
return rfr.nb
}
// readHole reads a sparse file hole ending at offset toOffset
func (sfr *sparseFileReader) readHole(b []byte, toOffset int64) int {
n64 := toOffset - sfr.pos
// newSparseFileReader creates a new sparseFileReader, but validates all of the
// sparse entries before doing so.
func newSparseFileReader(rfr numBytesReader, sp []sparseEntry, total int64) (*sparseFileReader, error) {
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))
}
@ -895,49 +1011,54 @@ func (sfr *sparseFileReader) readHole(b []byte, toOffset int64) int {
// Read reads the sparse file data in expanded form.
func (sfr *sparseFileReader) Read(b []byte) (n int, err error) {
if len(sfr.sp) == 0 {
// No more data fragments to read from.
if sfr.pos < sfr.tot {
// We're in the last hole
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 {
return 0, io.ErrUnexpectedEOF
}
if sfr.pos < sfr.sp[0].offset {
// We're in a hole
n = sfr.readHole(b, sfr.sp[0].offset)
return
// Skip past all empty fragments.
for len(sfr.sp) > 0 && sfr.sp[0].numBytes == 0 {
sfr.sp = sfr.sp[1:]
}
// We're not in a hole, so we'll read from the next data fragment
posInFragment := sfr.pos - sfr.sp[0].offset
bytesLeft := sfr.sp[0].numBytes - posInFragment
// 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.
// However, GNU tar stops returning data even if sfr.total is unmet.
if sfr.pos < sfr.total {
return sfr.readHole(b, sfr.total), nil
}
return 0, io.EOF
}
// In front of a data fragment, so read a hole.
if sfr.pos < sfr.sp[0].offset {
return sfr.readHole(b, sfr.sp[0].offset), nil
}
// In a data fragment, so read from it.
// This math is overflow free since we verify that offset and numBytes can
// be safely added when creating the sparseFileReader.
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[0:bytesLeft]
b = b[:bytesLeft]
}
n, err = sfr.rfr.Read(b)
sfr.pos += int64(n)
if int64(n) == bytesLeft {
// We're done with this fragment
sfr.sp = sfr.sp[1:]
if err == io.EOF {
if sfr.pos < endPos {
err = io.ErrUnexpectedEOF // There was supposed to be more data
} else if sfr.pos < sfr.total {
err = nil // There is still an implicit sparse hole at the end
}
}
if err == io.EOF && sfr.pos < sfr.tot {
// We reached the end of the last fragment's data, but there's a final hole
err = nil
if sfr.pos == endPos {
sfr.sp = sfr.sp[1:] // We are done with this fragment, so pop it
}
return
return n, err
}
// 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.nb
return sfr.rfr.numBytes()
}

222
vendor/src/github.com/vbatts/tar-split/archive/tar/writer.go vendored
View file

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