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archive/tar: adding from go as of a9dddb53f

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Vincent Batts 2015-02-11 14:08:03 +01:00
parent 70b9150cff
commit 64426b0aae
23 changed files with 3195 additions and 0 deletions
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305
archive/tar/common.go Normal file
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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package tar implements access to tar archives.
// It aims to cover most of the variations, including those produced
// by GNU and BSD tars.
//
// References:
// http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5
// http://www.gnu.org/software/tar/manual/html_node/Standard.html
// http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html
package tar
import (
"bytes"
"errors"
"fmt"
"os"
"path"
"time"
)
const (
blockSize = 512
// Types
TypeReg = '0' // regular file
TypeRegA = '\x00' // regular file
TypeLink = '1' // hard link
TypeSymlink = '2' // symbolic link
TypeChar = '3' // character device node
TypeBlock = '4' // block device node
TypeDir = '5' // directory
TypeFifo = '6' // fifo node
TypeCont = '7' // reserved
TypeXHeader = 'x' // extended header
TypeXGlobalHeader = 'g' // global extended header
TypeGNULongName = 'L' // Next file has a long name
TypeGNULongLink = 'K' // Next file symlinks to a file w/ a long name
TypeGNUSparse = 'S' // sparse file
)
// A Header represents a single header in a tar archive.
// Some fields may not be populated.
type Header struct {
Name string // name of header file entry
Mode int64 // permission and mode bits
Uid int // user id of owner
Gid int // group id of owner
Size int64 // length in bytes
ModTime time.Time // modified time
Typeflag byte // type of header entry
Linkname string // target name of link
Uname string // user name of owner
Gname string // group name of owner
Devmajor int64 // major number of character or block device
Devminor int64 // minor number of character or block device
AccessTime time.Time // access time
ChangeTime time.Time // status change time
Xattrs map[string]string
}
// File name constants from the tar spec.
const (
fileNameSize = 100 // Maximum number of bytes in a standard tar name.
fileNamePrefixSize = 155 // Maximum number of ustar extension bytes.
)
// FileInfo returns an os.FileInfo for the Header.
func (h *Header) FileInfo() os.FileInfo {
return headerFileInfo{h}
}
// headerFileInfo implements os.FileInfo.
type headerFileInfo struct {
h *Header
}
func (fi headerFileInfo) Size() int64 { return fi.h.Size }
func (fi headerFileInfo) IsDir() bool { return fi.Mode().IsDir() }
func (fi headerFileInfo) ModTime() time.Time { return fi.h.ModTime }
func (fi headerFileInfo) Sys() interface{} { return fi.h }
// Name returns the base name of the file.
func (fi headerFileInfo) Name() string {
if fi.IsDir() {
return path.Base(path.Clean(fi.h.Name))
}
return path.Base(fi.h.Name)
}
// Mode returns the permission and mode bits for the headerFileInfo.
func (fi headerFileInfo) Mode() (mode os.FileMode) {
// Set file permission bits.
mode = os.FileMode(fi.h.Mode).Perm()
// Set setuid, setgid and sticky bits.
if fi.h.Mode&c_ISUID != 0 {
// setuid
mode |= os.ModeSetuid
}
if fi.h.Mode&c_ISGID != 0 {
// setgid
mode |= os.ModeSetgid
}
if fi.h.Mode&c_ISVTX != 0 {
// sticky
mode |= os.ModeSticky
}
// Set file mode bits.
// clear perm, setuid, setgid and sticky bits.
m := os.FileMode(fi.h.Mode) &^ 07777
if m == c_ISDIR {
// directory
mode |= os.ModeDir
}
if m == c_ISFIFO {
// named pipe (FIFO)
mode |= os.ModeNamedPipe
}
if m == c_ISLNK {
// symbolic link
mode |= os.ModeSymlink
}
if m == c_ISBLK {
// device file
mode |= os.ModeDevice
}
if m == c_ISCHR {
// Unix character device
mode |= os.ModeDevice
mode |= os.ModeCharDevice
}
if m == c_ISSOCK {
// Unix domain socket
mode |= os.ModeSocket
}
switch fi.h.Typeflag {
case TypeLink, TypeSymlink:
// hard link, symbolic link
mode |= os.ModeSymlink
case TypeChar:
// character device node
mode |= os.ModeDevice
mode |= os.ModeCharDevice
case TypeBlock:
// block device node
mode |= os.ModeDevice
case TypeDir:
// directory
mode |= os.ModeDir
case TypeFifo:
// fifo node
mode |= os.ModeNamedPipe
}
return mode
}
// sysStat, if non-nil, populates h from system-dependent fields of fi.
var sysStat func(fi os.FileInfo, h *Header) error
// Mode constants from the tar spec.
const (
c_ISUID = 04000 // Set uid
c_ISGID = 02000 // Set gid
c_ISVTX = 01000 // Save text (sticky bit)
c_ISDIR = 040000 // Directory
c_ISFIFO = 010000 // FIFO
c_ISREG = 0100000 // Regular file
c_ISLNK = 0120000 // Symbolic link
c_ISBLK = 060000 // Block special file
c_ISCHR = 020000 // Character special file
c_ISSOCK = 0140000 // Socket
)
// Keywords for the PAX Extended Header
const (
paxAtime = "atime"
paxCharset = "charset"
paxComment = "comment"
paxCtime = "ctime" // please note that ctime is not a valid pax header.
paxGid = "gid"
paxGname = "gname"
paxLinkpath = "linkpath"
paxMtime = "mtime"
paxPath = "path"
paxSize = "size"
paxUid = "uid"
paxUname = "uname"
paxXattr = "SCHILY.xattr."
paxNone = ""
)
// FileInfoHeader creates a partially-populated Header from fi.
// If fi describes a symlink, FileInfoHeader records link as the link target.
// If fi describes a directory, a slash is appended to the name.
// Because os.FileInfo's Name method returns only the base name of
// the file it describes, it may be necessary to modify the Name field
// of the returned header to provide the full path name of the file.
func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
if fi == nil {
return nil, errors.New("tar: FileInfo is nil")
}
fm := fi.Mode()
h := &Header{
Name: fi.Name(),
ModTime: fi.ModTime(),
Mode: int64(fm.Perm()), // or'd with c_IS* constants later
}
switch {
case fm.IsRegular():
h.Mode |= c_ISREG
h.Typeflag = TypeReg
h.Size = fi.Size()
case fi.IsDir():
h.Typeflag = TypeDir
h.Mode |= c_ISDIR
h.Name += "/"
case fm&os.ModeSymlink != 0:
h.Typeflag = TypeSymlink
h.Mode |= c_ISLNK
h.Linkname = link
case fm&os.ModeDevice != 0:
if fm&os.ModeCharDevice != 0 {
h.Mode |= c_ISCHR
h.Typeflag = TypeChar
} else {
h.Mode |= c_ISBLK
h.Typeflag = TypeBlock
}
case fm&os.ModeNamedPipe != 0:
h.Typeflag = TypeFifo
h.Mode |= c_ISFIFO
case fm&os.ModeSocket != 0:
h.Mode |= c_ISSOCK
default:
return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm)
}
if fm&os.ModeSetuid != 0 {
h.Mode |= c_ISUID
}
if fm&os.ModeSetgid != 0 {
h.Mode |= c_ISGID
}
if fm&os.ModeSticky != 0 {
h.Mode |= c_ISVTX
}
if sysStat != nil {
return h, sysStat(fi, h)
}
return h, nil
}
var zeroBlock = make([]byte, blockSize)
// POSIX specifies a sum of the unsigned byte values, but the Sun tar uses signed byte values.
// We compute and return both.
func checksum(header []byte) (unsigned int64, signed int64) {
for i := 0; i < len(header); i++ {
if i == 148 {
// The chksum field (header[148:156]) is special: it should be treated as space bytes.
unsigned += ' ' * 8
signed += ' ' * 8
i += 7
continue
}
unsigned += int64(header[i])
signed += int64(int8(header[i]))
}
return
}
type slicer []byte
func (sp *slicer) next(n int) (b []byte) {
s := *sp
b, *sp = s[0:n], s[n:]
return
}
func isASCII(s string) bool {
for _, c := range s {
if c >= 0x80 {
return false
}
}
return true
}
func toASCII(s string) string {
if isASCII(s) {
return s
}
var buf bytes.Buffer
for _, c := range s {
if c < 0x80 {
buf.WriteByte(byte(c))
}
}
return buf.String()
}

80
archive/tar/example_test.go Normal file
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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tar_test
import (
"archive/tar"
"bytes"
"fmt"
"io"
"log"
"os"
)
func Example() {
// Create a buffer to write our archive to.
buf := new(bytes.Buffer)
// Create a new tar archive.
tw := tar.NewWriter(buf)
// Add some files to the archive.
var files = []struct {
Name, Body string
}{
{"readme.txt", "This archive contains some text files."},
{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
{"todo.txt", "Get animal handling licence."},
}
for _, file := range files {
hdr := &tar.Header{
Name: file.Name,
Mode: 0600,
Size: int64(len(file.Body)),
}
if err := tw.WriteHeader(hdr); err != nil {
log.Fatalln(err)
}
if _, err := tw.Write([]byte(file.Body)); err != nil {
log.Fatalln(err)
}
}
// Make sure to check the error on Close.
if err := tw.Close(); err != nil {
log.Fatalln(err)
}
// Open the tar archive for reading.
r := bytes.NewReader(buf.Bytes())
tr := tar.NewReader(r)
// Iterate through the files in the archive.
for {
hdr, err := tr.Next()
if err == io.EOF {
// end of tar archive
break
}
if err != nil {
log.Fatalln(err)
}
fmt.Printf("Contents of %s:\n", hdr.Name)
if _, err := io.Copy(os.Stdout, tr); err != nil {
log.Fatalln(err)
}
fmt.Println()
}
// Output:
// Contents of readme.txt:
// This archive contains some text files.
// Contents of gopher.txt:
// Gopher names:
// George
// Geoffrey
// Gonzo
// Contents of todo.txt:
// Get animal handling licence.
}

822
archive/tar/reader.go Normal file
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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tar
// TODO(dsymonds):
// - pax extensions
import (
"bytes"
"errors"
"io"
"io/ioutil"
"os"
"strconv"
"strings"
"time"
)
var (
ErrHeader = errors.New("archive/tar: invalid tar header")
)
const maxNanoSecondIntSize = 9
// A Reader provides sequential access to the contents of a tar archive.
// A tar archive consists of a sequence of files.
// The Next method advances to the next file in the archive (including the first),
// and then it can be treated as an io.Reader to access the file's data.
type Reader struct {
r io.Reader
err error
pad int64 // amount of padding (ignored) after current file entry
curr numBytesReader // reader for current file entry
hdrBuff [blockSize]byte // buffer to use in readHeader
}
// A numBytesReader is an io.Reader with a numBytes method, returning the number
// of bytes remaining in the underlying encoded data.
type numBytesReader interface {
io.Reader
numBytes() int64
}
// A regFileReader is a numBytesReader for reading file data from a tar archive.
type regFileReader struct {
r io.Reader // underlying reader
nb int64 // number of unread bytes for current file entry
}
// 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
}
// Keywords for GNU sparse files in a PAX extended header
const (
paxGNUSparseNumBlocks = "GNU.sparse.numblocks"
paxGNUSparseOffset = "GNU.sparse.offset"
paxGNUSparseNumBytes = "GNU.sparse.numbytes"
paxGNUSparseMap = "GNU.sparse.map"
paxGNUSparseName = "GNU.sparse.name"
paxGNUSparseMajor = "GNU.sparse.major"
paxGNUSparseMinor = "GNU.sparse.minor"
paxGNUSparseSize = "GNU.sparse.size"
paxGNUSparseRealSize = "GNU.sparse.realsize"
)
// Keywords for old GNU sparse headers
const (
oldGNUSparseMainHeaderOffset = 386
oldGNUSparseMainHeaderIsExtendedOffset = 482
oldGNUSparseMainHeaderNumEntries = 4
oldGNUSparseExtendedHeaderIsExtendedOffset = 504
oldGNUSparseExtendedHeaderNumEntries = 21
oldGNUSparseOffsetSize = 12
oldGNUSparseNumBytesSize = 12
)
// NewReader creates a new Reader reading from r.
func NewReader(r io.Reader) *Reader { return &Reader{r: r} }
// Next advances to the next entry in the tar archive.
//
// io.EOF is returned at the end of the input.
func (tr *Reader) Next() (*Header, error) {
var hdr *Header
if tr.err == nil {
tr.skipUnread()
}
if tr.err != nil {
return hdr, 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()
hdr = tr.readHeader()
mergePAX(hdr, headers)
// Check for a PAX format sparse file
sp, err := tr.checkForGNUSparsePAXHeaders(hdr, headers)
if err != nil {
tr.err = err
return nil, err
}
if sp != nil {
// 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
}
hdr, err := tr.Next()
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
}
hdr, err := tr.Next()
hdr.Linkname = cString(realname)
return hdr, err
}
return hdr, tr.err
}
// checkForGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers. If they are found, then
// this function reads the sparse map and returns it. Unknown sparse formats are ignored, causing the file to
// be treated as a regular file.
func (tr *Reader) checkForGNUSparsePAXHeaders(hdr *Header, headers map[string]string) ([]sparseEntry, error) {
var sparseFormat string
// Check for sparse format indicators
major, majorOk := headers[paxGNUSparseMajor]
minor, minorOk := headers[paxGNUSparseMinor]
sparseName, sparseNameOk := headers[paxGNUSparseName]
_, sparseMapOk := headers[paxGNUSparseMap]
sparseSize, sparseSizeOk := headers[paxGNUSparseSize]
sparseRealSize, sparseRealSizeOk := headers[paxGNUSparseRealSize]
// Identify which, if any, sparse format applies from which PAX headers are set
if majorOk && minorOk {
sparseFormat = major + "." + minor
} else if sparseNameOk && sparseMapOk {
sparseFormat = "0.1"
} else if sparseSizeOk {
sparseFormat = "0.0"
} else {
// Not a PAX format GNU sparse file.
return nil, nil
}
// Check for unknown sparse format
if sparseFormat != "0.0" && sparseFormat != "0.1" && sparseFormat != "1.0" {
return nil, nil
}
// Update hdr from GNU sparse PAX headers
if sparseNameOk {
hdr.Name = sparseName
}
if sparseSizeOk {
realSize, err := strconv.ParseInt(sparseSize, 10, 0)
if err != nil {
return nil, ErrHeader
}
hdr.Size = realSize
} else if sparseRealSizeOk {
realSize, err := strconv.ParseInt(sparseRealSize, 10, 0)
if err != nil {
return nil, ErrHeader
}
hdr.Size = realSize
}
// Set up the sparse map, according to the particular sparse format in use
var sp []sparseEntry
var err error
switch sparseFormat {
case "0.0", "0.1":
sp, err = readGNUSparseMap0x1(headers)
case "1.0":
sp, err = readGNUSparseMap1x0(tr.curr)
}
return sp, err
}
// mergePAX merges well known headers according to PAX standard.
// In general headers with the same name as those found
// in the header struct overwrite those found in the header
// struct with higher precision or longer values. Esp. useful
// for name and linkname fields.
func mergePAX(hdr *Header, headers map[string]string) error {
for k, v := range headers {
switch k {
case paxPath:
hdr.Name = v
case paxLinkpath:
hdr.Linkname = v
case paxGname:
hdr.Gname = v
case paxUname:
hdr.Uname = v
case paxUid:
uid, err := strconv.ParseInt(v, 10, 0)
if err != nil {
return err
}
hdr.Uid = int(uid)
case paxGid:
gid, err := strconv.ParseInt(v, 10, 0)
if err != nil {
return err
}
hdr.Gid = int(gid)
case paxAtime:
t, err := parsePAXTime(v)
if err != nil {
return err
}
hdr.AccessTime = t
case paxMtime:
t, err := parsePAXTime(v)
if err != nil {
return err
}
hdr.ModTime = t
case paxCtime:
t, err := parsePAXTime(v)
if err != nil {
return err
}
hdr.ChangeTime = t
case paxSize:
size, err := strconv.ParseInt(v, 10, 0)
if err != nil {
return err
}
hdr.Size = int64(size)
default:
if strings.HasPrefix(k, paxXattr) {
if hdr.Xattrs == nil {
hdr.Xattrs = make(map[string]string)
}
hdr.Xattrs[k[len(paxXattr):]] = v
}
}
}
return nil
}
// parsePAXTime takes a string of the form %d.%d as described in
// the PAX specification.
func parsePAXTime(t string) (time.Time, error) {
buf := []byte(t)
pos := bytes.IndexByte(buf, '.')
var seconds, nanoseconds int64
var err error
if pos == -1 {
seconds, err = strconv.ParseInt(t, 10, 0)
if err != nil {
return time.Time{}, err
}
} else {
seconds, err = strconv.ParseInt(string(buf[:pos]), 10, 0)
if err != nil {
return time.Time{}, err
}
nano_buf := string(buf[pos+1:])
// Pad as needed before converting to a decimal.
// For example .030 -> .030000000 -> 30000000 nanoseconds
if len(nano_buf) < maxNanoSecondIntSize {
// Right pad
nano_buf += strings.Repeat("0", maxNanoSecondIntSize-len(nano_buf))
} else if len(nano_buf) > maxNanoSecondIntSize {
// Right truncate
nano_buf = nano_buf[:maxNanoSecondIntSize]
}
nanoseconds, err = strconv.ParseInt(string(nano_buf), 10, 0)
if err != nil {
return time.Time{}, err
}
}
ts := time.Unix(seconds, nanoseconds)
return ts, nil
}
// parsePAX parses PAX headers.
// If an extended header (type 'x') is invalid, ErrHeader is returned
func parsePAX(r io.Reader) (map[string]string, error) {
buf, err := ioutil.ReadAll(r)
if err != nil {
return nil, err
}
// For GNU PAX sparse format 0.0 support.
// This function transforms the sparse format 0.0 headers into sparse format 0.1 headers.
var sparseMap bytes.Buffer
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 {
return nil, ErrHeader
}
// Parse the first token as a decimal integer.
n, err := strconv.ParseInt(string(buf[:sp]), 10, 0)
if err != nil {
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.Write(value)
sparseMap.Write([]byte{','})
} else {
// Normal key. Set the value in the headers map.
headers[keyStr] = string(value)
}
}
if sparseMap.Len() != 0 {
// Add sparse info to headers, chopping off the extra comma
sparseMap.Truncate(sparseMap.Len() - 1)
headers[paxGNUSparseMap] = sparseMap.String()
}
return headers, nil
}
// cString 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 {
n := 0
for n < len(b) && b[n] != 0 {
n++
}
return string(b[0:n])
}
func (tr *Reader) octal(b []byte) int64 {
// Check for binary format first.
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)
}
return x
}
// Because unused fields are filled with NULs, we need
// to skip leading NULs. Fields may also be padded with
// spaces or NULs.
// So we remove leading and trailing NULs and spaces to
// be sure.
b = bytes.Trim(b, " \x00")
if len(b) == 0 {
return 0
}
x, err := strconv.ParseUint(cString(b), 8, 64)
if err != nil {
tr.err = err
}
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
tr.curr, tr.pad = nil, 0
if sr, ok := tr.r.(io.Seeker); ok {
if _, err := sr.Seek(nr, os.SEEK_CUR); err == nil {
return
}
}
_, tr.err = io.CopyN(ioutil.Discard, tr.r, nr)
}
func (tr *Reader) verifyChecksum(header []byte) bool {
if tr.err != nil {
return false
}
given := tr.octal(header[148:156])
unsigned, signed := checksum(header)
return given == unsigned || given == signed
}
func (tr *Reader) readHeader() *Header {
header := tr.hdrBuff[:]
copy(header, zeroBlock)
if _, tr.err = io.ReadFull(tr.r, header); tr.err != nil {
return nil
}
// 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 {
return nil
}
if bytes.Equal(header, zeroBlock[0:blockSize]) {
tr.err = io.EOF
} else {
tr.err = ErrHeader // zero block and then non-zero block
}
return nil
}
if !tr.verifyChecksum(header) {
tr.err = ErrHeader
return nil
}
// Unpack
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))
hdr.ModTime = time.Unix(tr.octal(s.next(12)), 0)
s.next(8) // chksum
hdr.Typeflag = s.next(1)[0]
hdr.Linkname = cString(s.next(100))
// The remainder of the header depends on the value of magic.
// The original (v7) version of tar had no explicit magic field,
// so its magic bytes, like the rest of the block, are NULs.
magic := string(s.next(8)) // contains version field as well.
var format string
switch {
case magic[:6] == "ustar\x00": // POSIX tar (1003.1-1988)
if string(header[508:512]) == "tar\x00" {
format = "star"
} else {
format = "posix"
}
case magic == "ustar \x00": // old GNU tar
format = "gnu"
}
switch format {
case "posix", "gnu", "star":
hdr.Uname = cString(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 = tr.octal(devmajor)
hdr.Devminor = tr.octal(devminor)
}
var prefix string
switch format {
case "posix", "gnu":
prefix = cString(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)
}
if len(prefix) > 0 {
hdr.Name = prefix + "/" + hdr.Name
}
}
if tr.err != nil {
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.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])
// 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}
}
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 {
isExtended := header[oldGNUSparseMainHeaderIsExtendedOffset] != 0
spCap := oldGNUSparseMainHeaderNumEntries
if isExtended {
spCap += oldGNUSparseExtendedHeaderNumEntries
}
sp := make([]sparseEntry, 0, spCap)
s := slicer(header[oldGNUSparseMainHeaderOffset:])
// 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
return nil
}
if offset == 0 && numBytes == 0 {
break
}
sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
}
for isExtended {
// There are more entries. Read an extension header and parse its entries.
sparseHeader := make([]byte, blockSize)
if _, tr.err = io.ReadFull(tr.r, sparseHeader); tr.err != nil {
return nil
}
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
return nil
}
if offset == 0 && numBytes == 0 {
break
}
sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
}
}
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.
func readGNUSparseMap1x0(r io.Reader) ([]sparseEntry, error) {
buf := make([]byte, 2*blockSize)
sparseHeader := buf[: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
}
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
}
// 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
}
// Read the first block
if _, err := io.ReadFull(r, sparseHeader); err != nil {
return nil, err
}
// The first line contains the number of entries
numEntries, err := readDecimal()
if 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()
if err != nil {
return nil, err
}
// Read numBytes
numBytes, err := readDecimal()
if err != nil {
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 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 {
return nil, ErrHeader
}
sparseMap := strings.Split(headers[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
sp := make([]sparseEntry, 0, numEntries)
for i := int64(0); i < numEntries; i++ {
offset, err := strconv.ParseInt(sparseMap[2*i], 10, 0)
if err != nil {
return nil, ErrHeader
}
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
}
// numBytes returns the number of bytes left to read in the current file's entry
// in the tar archive, or 0 if there is no current file.
func (tr *Reader) numBytes() int64 {
if tr.curr == nil {
// No current file, so no bytes
return 0
}
return tr.curr.numBytes()
}
// 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.
func (tr *Reader) Read(b []byte) (n int, err error) {
if tr.curr == nil {
return 0, io.EOF
}
n, err = tr.curr.Read(b)
if err != nil && err != io.EOF {
tr.err = err
}
return
}
func (rfr *regFileReader) Read(b []byte) (n int, err error) {
if rfr.nb == 0 {
// file consumed
return 0, io.EOF
}
if int64(len(b)) > rfr.nb {
b = b[0:rfr.nb]
}
n, err = rfr.r.Read(b)
rfr.nb -= int64(n)
if err == io.EOF && rfr.nb > 0 {
err = io.ErrUnexpectedEOF
}
return
}
// numBytes returns the number of bytes left to read in the file's data in the tar archive.
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
if n64 > int64(len(b)) {
n64 = int64(len(b))
}
n := int(n64)
for i := 0; i < n; i++ {
b[i] = 0
}
sfr.pos += n64
return n
}
// 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.pos < sfr.sp[0].offset {
// We're in a hole
n = sfr.readHole(b, sfr.sp[0].offset)
return
}
// 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 int64(len(b)) > bytesLeft {
b = b[0: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 && sfr.pos < sfr.tot {
// We reached the end of the last fragment's data, but there's a final hole
err = nil
}
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.nb
}

743
archive/tar/reader_test.go Normal file
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@ -0,0 +1,743 @@
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tar
import (
"bytes"
"crypto/md5"
"fmt"
"io"
"io/ioutil"
"os"
"reflect"
"strings"
"testing"
"time"
)
type untarTest struct {
file string
headers []*Header
cksums []string
}
var gnuTarTest = &untarTest{
file: "testdata/gnu.tar",
headers: []*Header{
{
Name: "small.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 5,
ModTime: time.Unix(1244428340, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
},
{
Name: "small2.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 11,
ModTime: time.Unix(1244436044, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
},
},
cksums: []string{
"e38b27eaccb4391bdec553a7f3ae6b2f",
"c65bd2e50a56a2138bf1716f2fd56fe9",
},
}
var sparseTarTest = &untarTest{
file: "testdata/sparse-formats.tar",
headers: []*Header{
{
Name: "sparse-gnu",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392395740, 0),
Typeflag: 0x53,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "sparse-posix-0.0",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392342187, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "sparse-posix-0.1",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392340456, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "sparse-posix-1.0",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 200,
ModTime: time.Unix(1392337404, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
{
Name: "end",
Mode: 420,
Uid: 1000,
Gid: 1000,
Size: 4,
ModTime: time.Unix(1392398319, 0),
Typeflag: 0x30,
Linkname: "",
Uname: "david",
Gname: "david",
Devmajor: 0,
Devminor: 0,
},
},
cksums: []string{
"6f53234398c2449fe67c1812d993012f",
"6f53234398c2449fe67c1812d993012f",
"6f53234398c2449fe67c1812d993012f",
"6f53234398c2449fe67c1812d993012f",
"b0061974914468de549a2af8ced10316",
},
}
var untarTests = []*untarTest{
gnuTarTest,
sparseTarTest,
{
file: "testdata/star.tar",
headers: []*Header{
{
Name: "small.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 5,
ModTime: time.Unix(1244592783, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
AccessTime: time.Unix(1244592783, 0),
ChangeTime: time.Unix(1244592783, 0),
},
{
Name: "small2.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 11,
ModTime: time.Unix(1244592783, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
AccessTime: time.Unix(1244592783, 0),
ChangeTime: time.Unix(1244592783, 0),
},
},
},
{
file: "testdata/v7.tar",
headers: []*Header{
{
Name: "small.txt",
Mode: 0444,
Uid: 73025,
Gid: 5000,
Size: 5,
ModTime: time.Unix(1244593104, 0),
Typeflag: '\x00',
},
{
Name: "small2.txt",
Mode: 0444,
Uid: 73025,
Gid: 5000,
Size: 11,
ModTime: time.Unix(1244593104, 0),
Typeflag: '\x00',
},
},
},
{
file: "testdata/pax.tar",
headers: []*Header{
{
Name: "a/123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
Mode: 0664,
Uid: 1000,
Gid: 1000,
Uname: "shane",
Gname: "shane",
Size: 7,
ModTime: time.Unix(1350244992, 23960108),
ChangeTime: time.Unix(1350244992, 23960108),
AccessTime: time.Unix(1350244992, 23960108),
Typeflag: TypeReg,
},
{
Name: "a/b",
Mode: 0777,
Uid: 1000,
Gid: 1000,
Uname: "shane",
Gname: "shane",
Size: 0,
ModTime: time.Unix(1350266320, 910238425),
ChangeTime: time.Unix(1350266320, 910238425),
AccessTime: time.Unix(1350266320, 910238425),
Typeflag: TypeSymlink,
Linkname: "123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100",
},
},
},
{
file: "testdata/nil-uid.tar", // golang.org/issue/5290
headers: []*Header{
{
Name: "P1050238.JPG.log",
Mode: 0664,
Uid: 0,
Gid: 0,
Size: 14,
ModTime: time.Unix(1365454838, 0),
Typeflag: TypeReg,
Linkname: "",
Uname: "eyefi",
Gname: "eyefi",
Devmajor: 0,
Devminor: 0,
},
},
},
{
file: "testdata/xattrs.tar",
headers: []*Header{
{
Name: "small.txt",
Mode: 0644,
Uid: 1000,
Gid: 10,
Size: 5,
ModTime: time.Unix(1386065770, 448252320),
Typeflag: '0',
Uname: "alex",
Gname: "wheel",
AccessTime: time.Unix(1389782991, 419875220),
ChangeTime: time.Unix(1389782956, 794414986),
Xattrs: map[string]string{
"user.key": "value",
"user.key2": "value2",
// Interestingly, selinux encodes the terminating null inside the xattr
"security.selinux": "unconfined_u:object_r:default_t:s0\x00",
},
},
{
Name: "small2.txt",
Mode: 0644,
Uid: 1000,
Gid: 10,
Size: 11,
ModTime: time.Unix(1386065770, 449252304),
Typeflag: '0',
Uname: "alex",
Gname: "wheel",
AccessTime: time.Unix(1389782991, 419875220),
ChangeTime: time.Unix(1386065770, 449252304),
Xattrs: map[string]string{
"security.selinux": "unconfined_u:object_r:default_t:s0\x00",
},
},
},
},
}
func TestReader(t *testing.T) {
testLoop:
for i, test := range untarTests {
f, err := os.Open(test.file)
if err != nil {
t.Errorf("test %d: Unexpected error: %v", i, err)
continue
}
defer f.Close()
tr := NewReader(f)
for j, header := range test.headers {
hdr, err := tr.Next()
if err != nil || hdr == nil {
t.Errorf("test %d, entry %d: Didn't get entry: %v", i, j, err)
f.Close()
continue testLoop
}
if !reflect.DeepEqual(*hdr, *header) {
t.Errorf("test %d, entry %d: Incorrect header:\nhave %+v\nwant %+v",
i, j, *hdr, *header)
}
}
hdr, err := tr.Next()
if err == io.EOF {
continue testLoop
}
if hdr != nil || err != nil {
t.Errorf("test %d: Unexpected entry or error: hdr=%v err=%v", i, hdr, err)
}
}
}
func TestPartialRead(t *testing.T) {
f, err := os.Open("testdata/gnu.tar")
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
defer f.Close()
tr := NewReader(f)
// Read the first four bytes; Next() should skip the last byte.
hdr, err := tr.Next()
if err != nil || hdr == nil {
t.Fatalf("Didn't get first file: %v", err)
}
buf := make([]byte, 4)
if _, err := io.ReadFull(tr, buf); err != nil {
t.Fatalf("Unexpected error: %v", err)
}
if expected := []byte("Kilt"); !bytes.Equal(buf, expected) {
t.Errorf("Contents = %v, want %v", buf, expected)
}
// Second file
hdr, err = tr.Next()
if err != nil || hdr == nil {
t.Fatalf("Didn't get second file: %v", err)
}
buf = make([]byte, 6)
if _, err := io.ReadFull(tr, buf); err != nil {
t.Fatalf("Unexpected error: %v", err)
}
if expected := []byte("Google"); !bytes.Equal(buf, expected) {
t.Errorf("Contents = %v, want %v", buf, expected)
}
}
func TestIncrementalRead(t *testing.T) {
test := gnuTarTest
f, err := os.Open(test.file)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
defer f.Close()
tr := NewReader(f)
headers := test.headers
cksums := test.cksums
nread := 0
// loop over all files
for ; ; nread++ {
hdr, err := tr.Next()
if hdr == nil || err == io.EOF {
break
}
// check the header
if !reflect.DeepEqual(*hdr, *headers[nread]) {
t.Errorf("Incorrect header:\nhave %+v\nwant %+v",
*hdr, headers[nread])
}
// read file contents in little chunks EOF,
// checksumming all the way
h := md5.New()
rdbuf := make([]uint8, 8)
for {
nr, err := tr.Read(rdbuf)
if err == io.EOF {
break
}
if err != nil {
t.Errorf("Read: unexpected error %v\n", err)
break
}
h.Write(rdbuf[0:nr])
}
// verify checksum
have := fmt.Sprintf("%x", h.Sum(nil))
want := cksums[nread]
if want != have {
t.Errorf("Bad checksum on file %s:\nhave %+v\nwant %+v", hdr.Name, have, want)
}
}
if nread != len(headers) {
t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(headers), nread)
}
}
func TestNonSeekable(t *testing.T) {
test := gnuTarTest
f, err := os.Open(test.file)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
defer f.Close()
type readerOnly struct {
io.Reader
}
tr := NewReader(readerOnly{f})
nread := 0
for ; ; nread++ {
_, err := tr.Next()
if err == io.EOF {
break
}
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
}
if nread != len(test.headers) {
t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(test.headers), nread)
}
}
func TestParsePAXHeader(t *testing.T) {
paxTests := [][3]string{
{"a", "a=name", "10 a=name\n"}, // Test case involving multiple acceptable lengths
{"a", "a=name", "9 a=name\n"}, // Test case involving multiple acceptable length
{"mtime", "mtime=1350244992.023960108", "30 mtime=1350244992.023960108\n"}}
for _, test := range paxTests {
key, expected, raw := test[0], test[1], test[2]
reader := bytes.NewReader([]byte(raw))
headers, err := parsePAX(reader)
if err != nil {
t.Errorf("Couldn't parse correctly formatted headers: %v", err)
continue
}
if strings.EqualFold(headers[key], expected) {
t.Errorf("mtime header incorrectly parsed: got %s, wanted %s", headers[key], expected)
continue
}
trailer := make([]byte, 100)
n, err := reader.Read(trailer)
if err != io.EOF || n != 0 {
t.Error("Buffer wasn't consumed")
}
}
badHeader := bytes.NewReader([]byte("3 somelongkey="))
if _, err := parsePAX(badHeader); err != ErrHeader {
t.Fatal("Unexpected success when parsing bad header")
}
}
func TestParsePAXTime(t *testing.T) {
// Some valid PAX time values
timestamps := map[string]time.Time{
"1350244992.023960108": time.Unix(1350244992, 23960108), // The common case
"1350244992.02396010": time.Unix(1350244992, 23960100), // Lower precision value
"1350244992.0239601089": time.Unix(1350244992, 23960108), // Higher precision value
"1350244992": time.Unix(1350244992, 0), // Low precision value
}
for input, expected := range timestamps {
ts, err := parsePAXTime(input)
if err != nil {
t.Fatal(err)
}
if !ts.Equal(expected) {
t.Fatalf("Time parsing failure %s %s", ts, expected)
}
}
}
func TestMergePAX(t *testing.T) {
hdr := new(Header)
// Test a string, integer, and time based value.
headers := map[string]string{
"path": "a/b/c",
"uid": "1000",
"mtime": "1350244992.023960108",
}
err := mergePAX(hdr, headers)
if err != nil {
t.Fatal(err)
}
want := &Header{
Name: "a/b/c",
Uid: 1000,
ModTime: time.Unix(1350244992, 23960108),
}
if !reflect.DeepEqual(hdr, want) {
t.Errorf("incorrect merge: got %+v, want %+v", hdr, want)
}
}
func TestSparseEndToEnd(t *testing.T) {
test := sparseTarTest
f, err := os.Open(test.file)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
defer f.Close()
tr := NewReader(f)
headers := test.headers
cksums := test.cksums
nread := 0
// loop over all files
for ; ; nread++ {
hdr, err := tr.Next()
if hdr == nil || err == io.EOF {
break
}
// check the header
if !reflect.DeepEqual(*hdr, *headers[nread]) {
t.Errorf("Incorrect header:\nhave %+v\nwant %+v",
*hdr, headers[nread])
}
// read and checksum the file data
h := md5.New()
_, err = io.Copy(h, tr)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
// verify checksum
have := fmt.Sprintf("%x", h.Sum(nil))
want := cksums[nread]
if want != have {
t.Errorf("Bad checksum on file %s:\nhave %+v\nwant %+v", hdr.Name, have, want)
}
}
if nread != len(headers) {
t.Errorf("Didn't process all files\nexpected: %d\nprocessed %d\n", len(headers), nread)
}
}
type sparseFileReadTest struct {
sparseData []byte
sparseMap []sparseEntry
realSize int64
expected []byte
}
var sparseFileReadTests = []sparseFileReadTest{
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 0, numBytes: 2},
{offset: 5, numBytes: 3},
},
realSize: 8,
expected: []byte("ab\x00\x00\x00cde"),
},
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 0, numBytes: 2},
{offset: 5, numBytes: 3},
},
realSize: 10,
expected: []byte("ab\x00\x00\x00cde\x00\x00"),
},
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 1, numBytes: 3},
{offset: 6, numBytes: 2},
},
realSize: 8,
expected: []byte("\x00abc\x00\x00de"),
},
{
sparseData: []byte("abcde"),
sparseMap: []sparseEntry{
{offset: 1, numBytes: 3},
{offset: 6, numBytes: 2},
},
realSize: 10,
expected: []byte("\x00abc\x00\x00de\x00\x00"),
},
{
sparseData: []byte(""),
sparseMap: nil,
realSize: 2,
expected: []byte("\x00\x00"),
},
}
func TestSparseFileReader(t *testing.T) {
for i, test := range sparseFileReadTests {
r := bytes.NewReader(test.sparseData)
nb := int64(r.Len())
sfr := &sparseFileReader{
rfr: &regFileReader{r: r, nb: nb},
sp: test.sparseMap,
pos: 0,
tot: test.realSize,
}
if sfr.numBytes() != nb {
t.Errorf("test %d: Before reading, sfr.numBytes() = %d, want %d", i, sfr.numBytes(), nb)
}
buf, err := ioutil.ReadAll(sfr)
if err != nil {
t.Errorf("test %d: Unexpected error: %v", i, err)
}
if e := test.expected; !bytes.Equal(buf, e) {
t.Errorf("test %d: Contents = %v, want %v", i, buf, e)
}
if sfr.numBytes() != 0 {
t.Errorf("test %d: After draining the reader, numBytes() was nonzero", i)
}
}
}
func TestSparseIncrementalRead(t *testing.T) {
sparseMap := []sparseEntry{{10, 2}}
sparseData := []byte("Go")
expected := "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00Go\x00\x00\x00\x00\x00\x00\x00\x00"
r := bytes.NewReader(sparseData)
nb := int64(r.Len())
sfr := &sparseFileReader{
rfr: &regFileReader{r: r, nb: nb},
sp: sparseMap,
pos: 0,
tot: int64(len(expected)),
}
// We'll read the data 6 bytes at a time, with a hole of size 10 at
// the beginning and one of size 8 at the end.
var outputBuf bytes.Buffer
buf := make([]byte, 6)
for {
n, err := sfr.Read(buf)
if err == io.EOF {
break
}
if err != nil {
t.Errorf("Read: unexpected error %v\n", err)
}
if n > 0 {
_, err := outputBuf.Write(buf[:n])
if err != nil {
t.Errorf("Write: unexpected error %v\n", err)
}
}
}
got := outputBuf.String()
if got != expected {
t.Errorf("Contents = %v, want %v", got, expected)
}
}
func TestReadGNUSparseMap0x1(t *testing.T) {
headers := map[string]string{
paxGNUSparseNumBlocks: "4",
paxGNUSparseMap: "0,5,10,5,20,5,30,5",
}
expected := []sparseEntry{
{offset: 0, numBytes: 5},
{offset: 10, numBytes: 5},
{offset: 20, numBytes: 5},
{offset: 30, numBytes: 5},
}
sp, err := readGNUSparseMap0x1(headers)
if err != nil {
t.Errorf("Unexpected error: %v", err)
}
if !reflect.DeepEqual(sp, expected) {
t.Errorf("Incorrect sparse map: got %v, wanted %v", sp, expected)
}
}
func TestReadGNUSparseMap1x0(t *testing.T) {
// This test uses lots of holes so the sparse header takes up more than two blocks
numEntries := 100
expected := make([]sparseEntry, 0, numEntries)
sparseMap := new(bytes.Buffer)
fmt.Fprintf(sparseMap, "%d\n", numEntries)
for i := 0; i < numEntries; i++ {
offset := int64(2048 * i)
numBytes := int64(1024)
expected = append(expected, sparseEntry{offset: offset, numBytes: numBytes})
fmt.Fprintf(sparseMap, "%d\n%d\n", offset, numBytes)
}
// Make the header the smallest multiple of blockSize that fits the sparseMap
headerBlocks := (sparseMap.Len() + blockSize - 1) / blockSize
bufLen := blockSize * headerBlocks
buf := make([]byte, bufLen)
copy(buf, sparseMap.Bytes())
// Get an reader to read the sparse map
r := bytes.NewReader(buf)
// Read the sparse map
sp, err := readGNUSparseMap1x0(r)
if err != nil {
t.Errorf("Unexpected error: %v", err)
}
if !reflect.DeepEqual(sp, expected) {
t.Errorf("Incorrect sparse map: got %v, wanted %v", sp, expected)
}
}
func TestUninitializedRead(t *testing.T) {
test := gnuTarTest
f, err := os.Open(test.file)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
defer f.Close()
tr := NewReader(f)
_, err = tr.Read([]byte{})
if err == nil || err != io.EOF {
t.Errorf("Unexpected error: %v, wanted %v", err, io.EOF)
}
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build linux dragonfly openbsd solaris
package tar
import (
"syscall"
"time"
)
func statAtime(st *syscall.Stat_t) time.Time {
return time.Unix(st.Atim.Unix())
}
func statCtime(st *syscall.Stat_t) time.Time {
return time.Unix(st.Ctim.Unix())
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build darwin freebsd netbsd
package tar
import (
"syscall"
"time"
)
func statAtime(st *syscall.Stat_t) time.Time {
return time.Unix(st.Atimespec.Unix())
}
func statCtime(st *syscall.Stat_t) time.Time {
return time.Unix(st.Ctimespec.Unix())
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build linux darwin dragonfly freebsd openbsd netbsd solaris
package tar
import (
"os"
"syscall"
)
func init() {
sysStat = statUnix
}
func statUnix(fi os.FileInfo, h *Header) error {
sys, ok := fi.Sys().(*syscall.Stat_t)
if !ok {
return nil
}
h.Uid = int(sys.Uid)
h.Gid = int(sys.Gid)
// TODO(bradfitz): populate username & group. os/user
// doesn't cache LookupId lookups, and lacks group
// lookup functions.
h.AccessTime = statAtime(sys)
h.ChangeTime = statCtime(sys)
// TODO(bradfitz): major/minor device numbers?
return nil
}

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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tar
import (
"bytes"
"io/ioutil"
"os"
"path"
"reflect"
"strings"
"testing"
"time"
)
func TestFileInfoHeader(t *testing.T) {
fi, err := os.Stat("testdata/small.txt")
if err != nil {
t.Fatal(err)
}
h, err := FileInfoHeader(fi, "")
if err != nil {
t.Fatalf("FileInfoHeader: %v", err)
}
if g, e := h.Name, "small.txt"; g != e {
t.Errorf("Name = %q; want %q", g, e)
}
if g, e := h.Mode, int64(fi.Mode().Perm())|c_ISREG; g != e {
t.Errorf("Mode = %#o; want %#o", g, e)
}
if g, e := h.Size, int64(5); g != e {
t.Errorf("Size = %v; want %v", g, e)
}
if g, e := h.ModTime, fi.ModTime(); !g.Equal(e) {
t.Errorf("ModTime = %v; want %v", g, e)
}
// FileInfoHeader should error when passing nil FileInfo
if _, err := FileInfoHeader(nil, ""); err == nil {
t.Fatalf("Expected error when passing nil to FileInfoHeader")
}
}
func TestFileInfoHeaderDir(t *testing.T) {
fi, err := os.Stat("testdata")
if err != nil {
t.Fatal(err)
}
h, err := FileInfoHeader(fi, "")
if err != nil {
t.Fatalf("FileInfoHeader: %v", err)
}
if g, e := h.Name, "testdata/"; g != e {
t.Errorf("Name = %q; want %q", g, e)
}
// Ignoring c_ISGID for golang.org/issue/4867
if g, e := h.Mode&^c_ISGID, int64(fi.Mode().Perm())|c_ISDIR; g != e {
t.Errorf("Mode = %#o; want %#o", g, e)
}
if g, e := h.Size, int64(0); g != e {
t.Errorf("Size = %v; want %v", g, e)
}
if g, e := h.ModTime, fi.ModTime(); !g.Equal(e) {
t.Errorf("ModTime = %v; want %v", g, e)
}
}
func TestFileInfoHeaderSymlink(t *testing.T) {
h, err := FileInfoHeader(symlink{}, "some-target")
if err != nil {
t.Fatal(err)
}
if g, e := h.Name, "some-symlink"; g != e {
t.Errorf("Name = %q; want %q", g, e)
}
if g, e := h.Linkname, "some-target"; g != e {
t.Errorf("Linkname = %q; want %q", g, e)
}
}
type symlink struct{}
func (symlink) Name() string { return "some-symlink" }
func (symlink) Size() int64 { return 0 }
func (symlink) Mode() os.FileMode { return os.ModeSymlink }
func (symlink) ModTime() time.Time { return time.Time{} }
func (symlink) IsDir() bool { return false }
func (symlink) Sys() interface{} { return nil }
func TestRoundTrip(t *testing.T) {
data := []byte("some file contents")
var b bytes.Buffer
tw := NewWriter(&b)
hdr := &Header{
Name: "file.txt",
Uid: 1 << 21, // too big for 8 octal digits
Size: int64(len(data)),
ModTime: time.Now(),
}
// 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)
}
if _, err := tw.Write(data); err != nil {
t.Fatalf("tw.Write: %v", err)
}
if err := tw.Close(); err != nil {
t.Fatalf("tw.Close: %v", err)
}
// Read it back.
tr := NewReader(&b)
rHdr, err := tr.Next()
if err != nil {
t.Fatalf("tr.Next: %v", err)
}
if !reflect.DeepEqual(rHdr, hdr) {
t.Errorf("Header mismatch.\n got %+v\nwant %+v", rHdr, hdr)
}
rData, err := ioutil.ReadAll(tr)
if err != nil {
t.Fatalf("Read: %v", err)
}
if !bytes.Equal(rData, data) {
t.Errorf("Data mismatch.\n got %q\nwant %q", rData, data)
}
}
type headerRoundTripTest struct {
h *Header
fm os.FileMode
}
func TestHeaderRoundTrip(t *testing.T) {
golden := []headerRoundTripTest{
// regular file.
{
h: &Header{
Name: "test.txt",
Mode: 0644 | c_ISREG,
Size: 12,
ModTime: time.Unix(1360600916, 0),
Typeflag: TypeReg,
},
fm: 0644,
},
// hard link.
{
h: &Header{
Name: "hard.txt",
Mode: 0644 | c_ISLNK,
Size: 0,
ModTime: time.Unix(1360600916, 0),
Typeflag: TypeLink,
},
fm: 0644 | os.ModeSymlink,
},
// symbolic link.
{
h: &Header{
Name: "link.txt",
Mode: 0777 | c_ISLNK,
Size: 0,
ModTime: time.Unix(1360600852, 0),
Typeflag: TypeSymlink,
},
fm: 0777 | os.ModeSymlink,
},
// character device node.
{
h: &Header{
Name: "dev/null",
Mode: 0666 | c_ISCHR,
Size: 0,
ModTime: time.Unix(1360578951, 0),
Typeflag: TypeChar,
},
fm: 0666 | os.ModeDevice | os.ModeCharDevice,
},
// block device node.
{
h: &Header{
Name: "dev/sda",
Mode: 0660 | c_ISBLK,
Size: 0,
ModTime: time.Unix(1360578954, 0),
Typeflag: TypeBlock,
},
fm: 0660 | os.ModeDevice,
},
// directory.
{
h: &Header{
Name: "dir/",
Mode: 0755 | c_ISDIR,
Size: 0,
ModTime: time.Unix(1360601116, 0),
Typeflag: TypeDir,
},
fm: 0755 | os.ModeDir,
},
// fifo node.
{
h: &Header{
Name: "dev/initctl",
Mode: 0600 | c_ISFIFO,
Size: 0,
ModTime: time.Unix(1360578949, 0),
Typeflag: TypeFifo,
},
fm: 0600 | os.ModeNamedPipe,
},
// setuid.
{
h: &Header{
Name: "bin/su",
Mode: 0755 | c_ISREG | c_ISUID,
Size: 23232,
ModTime: time.Unix(1355405093, 0),
Typeflag: TypeReg,
},
fm: 0755 | os.ModeSetuid,
},
// setguid.
{
h: &Header{
Name: "group.txt",
Mode: 0750 | c_ISREG | c_ISGID,
Size: 0,
ModTime: time.Unix(1360602346, 0),
Typeflag: TypeReg,
},
fm: 0750 | os.ModeSetgid,
},
// sticky.
{
h: &Header{
Name: "sticky.txt",
Mode: 0600 | c_ISREG | c_ISVTX,
Size: 7,
ModTime: time.Unix(1360602540, 0),
Typeflag: TypeReg,
},
fm: 0600 | os.ModeSticky,
},
}
for i, g := range golden {
fi := g.h.FileInfo()
h2, err := FileInfoHeader(fi, "")
if err != nil {
t.Error(err)
continue
}
if strings.Contains(fi.Name(), "/") {
t.Errorf("FileInfo of %q contains slash: %q", g.h.Name, fi.Name())
}
name := path.Base(g.h.Name)
if fi.IsDir() {
name += "/"
}
if got, want := h2.Name, name; got != want {
t.Errorf("i=%d: Name: got %v, want %v", i, got, want)
}
if got, want := h2.Size, g.h.Size; got != want {
t.Errorf("i=%d: Size: got %v, want %v", i, got, want)
}
if got, want := h2.Mode, g.h.Mode; got != want {
t.Errorf("i=%d: Mode: got %o, want %o", i, got, want)
}
if got, want := fi.Mode(), g.fm; got != want {
t.Errorf("i=%d: fi.Mode: got %o, want %o", i, got, want)
}
if got, want := h2.ModTime, g.h.ModTime; got != want {
t.Errorf("i=%d: ModTime: got %v, want %v", i, got, want)
}
if sysh, ok := fi.Sys().(*Header); !ok || sysh != g.h {
t.Errorf("i=%d: Sys didn't return original *Header", i)
}
}
}

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// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tar
// TODO(dsymonds):
// - catch more errors (no first header, etc.)
import (
"bytes"
"errors"
"fmt"
"io"
"os"
"path"
"strconv"
"strings"
"time"
)
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")
)
// A Writer provides sequential writing of a tar archive in POSIX.1 format.
// A tar archive consists of a sequence of files.
// Call WriteHeader to begin a new file, and then call Write to supply that file's data,
// writing at most hdr.Size bytes in total.
type Writer struct {
w io.Writer
err error
nb int64 // number of unwritten bytes for current file entry
pad int64 // amount of padding to write after current file entry
closed bool
usedBinary bool // whether the binary numeric field extension was used
preferPax bool // use pax header instead of binary numeric header
hdrBuff [blockSize]byte // buffer to use in writeHeader when writing a regular header
paxHdrBuff [blockSize]byte // buffer to use in writeHeader when writing a pax header
}
// NewWriter creates a new Writer writing to w.
func NewWriter(w io.Writer) *Writer { return &Writer{w: w} }
// Flush finishes writing the current file (optional).
func (tw *Writer) Flush() error {
if tw.nb > 0 {
tw.err = fmt.Errorf("archive/tar: missed writing %d bytes", tw.nb)
return tw.err
}
n := tw.nb + tw.pad
for n > 0 && tw.err == nil {
nr := n
if nr > blockSize {
nr = blockSize
}
var nw int
nw, tw.err = tw.w.Write(zeroBlock[0:nr])
n -= int64(nw)
}
tw.nb = 0
tw.pad = 0
return tw.err
}
// 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
}
if len(s) > len(b) {
if tw.err == nil {
tw.err = ErrFieldTooLong
}
return
}
ascii := toASCII(s)
copy(b, ascii)
if len(ascii) < len(b) {
b[len(ascii)] = 0
}
}
// Encode x as an octal ASCII string and write it into b with leading zeros.
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
}
tw.cString(b, s, false, paxNone, nil)
}
// 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)
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
}
var (
minTime = time.Unix(0, 0)
// There is room for 11 octal digits (33 bits) of mtime.
maxTime = minTime.Add((1<<33 - 1) * time.Second)
)
// WriteHeader writes hdr and prepares to accept the file's contents.
// WriteHeader calls Flush if it is not the first header.
// Calling after a Close will return ErrWriteAfterClose.
func (tw *Writer) WriteHeader(hdr *Header) error {
return tw.writeHeader(hdr, true)
}
// WriteHeader writes hdr and prepares to accept the file's contents.
// WriteHeader calls Flush if it is not the first header.
// Calling after a Close will return ErrWriteAfterClose.
// As this method is called internally by writePax header to allow it to
// suppress writing the pax header.
func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
if tw.closed {
return ErrWriteAfterClose
}
if tw.err == nil {
tw.Flush()
}
if tw.err != nil {
return tw.err
}
// a map to hold pax header records, if any are needed
paxHeaders := make(map[string]string)
// TODO(shanemhansen): we might want to use PAX headers for
// subsecond time resolution, but for now let's just capture
// too long fields or non ascii characters
var header []byte
// We need to select which scratch buffer to use carefully,
// since this method is called recursively to write PAX headers.
// If allowPax is true, this is the non-recursive call, and we will use hdrBuff.
// If allowPax is false, we are being called by writePAXHeader, and hdrBuff is
// already being used by the non-recursive call, so we must use paxHdrBuff.
header = tw.hdrBuff[:]
if !allowPax {
header = tw.paxHdrBuff[:]
}
copy(header, zeroBlock)
s := slicer(header)
// 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)
// Handle out of range ModTime carefully.
var modTime int64
if !hdr.ModTime.Before(minTime) && !hdr.ModTime.After(maxTime) {
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
tw.cString(s.next(100), hdr.Linkname, true, paxLinkpath, paxHeaders)
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
// 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
// Use the GNU magic instead of POSIX magic if we used any GNU extensions.
if tw.usedBinary {
copy(header[257:265], []byte("ustar \x00"))
}
_, 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
// 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"))
}
}
}
}
// 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)
header[155] = ' '
if tw.err != nil {
// problem with header; probably integer too big for a field.
return tw.err
}
if allowPax {
for k, v := range hdr.Xattrs {
paxHeaders[paxXattr+k] = v
}
}
if len(paxHeaders) > 0 {
if !allowPax {
return errInvalidHeader
}
if err := tw.writePAXHeader(hdr, paxHeaders); err != nil {
return err
}
}
tw.nb = int64(hdr.Size)
tw.pad = (blockSize - (tw.nb % blockSize)) % blockSize
_, tw.err = tw.w.Write(header)
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) {
length := len(name)
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
if i <= 0 || nlen > fileNameSize || nlen == 0 || plen > fileNamePrefixSize {
err = errNameTooLong
return
}
prefix, suffix = name[:i], name[i+1:]
return
}
// writePaxHeader writes an extended pax header to the
// archive.
func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) error {
// Prepare extended header
ext := new(Header)
ext.Typeflag = TypeXHeader
// Setting ModTime is required for reader parsing to
// 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()
dir, file := path.Split(hdr.Name)
fullName := path.Join(dir,
fmt.Sprintf("PaxHeaders.%d", pid), file)
ascii := toASCII(fullName)
if len(ascii) > 100 {
ascii = ascii[:100]
}
ext.Name = ascii
// Construct the body
var buf bytes.Buffer
for k, v := range paxHeaders {
fmt.Fprint(&buf, paxHeader(k+"="+v))
}
ext.Size = int64(len(buf.Bytes()))
if err := tw.writeHeader(ext, false); err != nil {
return err
}
if _, err := tw.Write(buf.Bytes()); err != nil {
return err
}
if err := tw.Flush(); err != nil {
return err
}
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
size += len(strconv.Itoa(size))
record := fmt.Sprintf("%d %s\n", size, msg)
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)
}
return record
}
// Write writes to the current entry in the tar archive.
// Write returns the error ErrWriteTooLong if more than
// hdr.Size bytes are written after WriteHeader.
func (tw *Writer) Write(b []byte) (n int, err error) {
if tw.closed {
err = ErrWriteTooLong
return
}
overwrite := false
if int64(len(b)) > tw.nb {
b = b[0:tw.nb]
overwrite = true
}
n, err = tw.w.Write(b)
tw.nb -= int64(n)
if err == nil && overwrite {
err = ErrWriteTooLong
return
}
tw.err = err
return
}
// Close closes the tar archive, flushing any unwritten
// data to the underlying writer.
func (tw *Writer) Close() error {
if tw.err != nil || tw.closed {
return tw.err
}
tw.Flush()
tw.closed = true
if tw.err != nil {
return tw.err
}
// trailer: two zero blocks
for i := 0; i < 2; i++ {
_, tw.err = tw.w.Write(zeroBlock)
if tw.err != nil {
break
}
}
return tw.err
}

491
archive/tar/writer_test.go Normal file
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@ -0,0 +1,491 @@
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tar
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
"reflect"
"strings"
"testing"
"testing/iotest"
"time"
)
type writerTestEntry struct {
header *Header
contents string
}
type writerTest struct {
file string // filename of expected output
entries []*writerTestEntry
}
var writerTests = []*writerTest{
// The writer test file was produced with this command:
// tar (GNU tar) 1.26
// ln -s small.txt link.txt
// tar -b 1 --format=ustar -c -f writer.tar small.txt small2.txt link.txt
{
file: "testdata/writer.tar",
entries: []*writerTestEntry{
{
header: &Header{
Name: "small.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 5,
ModTime: time.Unix(1246508266, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
},
contents: "Kilts",
},
{
header: &Header{
Name: "small2.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 11,
ModTime: time.Unix(1245217492, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
},
contents: "Google.com\n",
},
{
header: &Header{
Name: "link.txt",
Mode: 0777,
Uid: 1000,
Gid: 1000,
Size: 0,
ModTime: time.Unix(1314603082, 0),
Typeflag: '2',
Linkname: "small.txt",
Uname: "strings",
Gname: "strings",
},
// no contents
},
},
},
// The truncated test file was produced using these commands:
// dd if=/dev/zero bs=1048576 count=16384 > /tmp/16gig.txt
// tar -b 1 -c -f- /tmp/16gig.txt | dd bs=512 count=8 > writer-big.tar
{
file: "testdata/writer-big.tar",
entries: []*writerTestEntry{
{
header: &Header{
Name: "tmp/16gig.txt",
Mode: 0640,
Uid: 73025,
Gid: 5000,
Size: 16 << 30,
ModTime: time.Unix(1254699560, 0),
Typeflag: '0',
Uname: "dsymonds",
Gname: "eng",
},
// fake contents
contents: strings.Repeat("\x00", 4<<10),
},
},
},
// The truncated test file was produced using these commands:
// dd if=/dev/zero bs=1048576 count=16384 > (longname/)*15 /16gig.txt
// tar -b 1 -c -f- (longname/)*15 /16gig.txt | dd bs=512 count=8 > writer-big-long.tar
{
file: "testdata/writer-big-long.tar",
entries: []*writerTestEntry{
{
header: &Header{
Name: strings.Repeat("longname/", 15) + "16gig.txt",
Mode: 0644,
Uid: 1000,
Gid: 1000,
Size: 16 << 30,
ModTime: time.Unix(1399583047, 0),
Typeflag: '0',
Uname: "guillaume",
Gname: "guillaume",
},
// fake contents
contents: strings.Repeat("\x00", 4<<10),
},
},
},
// This file was produced using gnu tar 1.17
// gnutar -b 4 --format=ustar (longname/)*15 + file.txt
{
file: "testdata/ustar.tar",
entries: []*writerTestEntry{
{
header: &Header{
Name: strings.Repeat("longname/", 15) + "file.txt",
Mode: 0644,
Uid: 0765,
Gid: 024,
Size: 06,
ModTime: time.Unix(1360135598, 0),
Typeflag: '0',
Uname: "shane",
Gname: "staff",
},
contents: "hello\n",
},
},
},
}
// Render byte array in a two-character hexadecimal string, spaced for easy visual inspection.
func bytestr(offset int, b []byte) string {
const rowLen = 32
s := fmt.Sprintf("%04x ", offset)
for _, ch := range b {
switch {
case '0' <= ch && ch <= '9', 'A' <= ch && ch <= 'Z', 'a' <= ch && ch <= 'z':
s += fmt.Sprintf(" %c", ch)
default:
s += fmt.Sprintf(" %02x", ch)
}
}
return s
}
// Render a pseudo-diff between two blocks of bytes.
func bytediff(a []byte, b []byte) string {
const rowLen = 32
s := fmt.Sprintf("(%d bytes vs. %d bytes)\n", len(a), len(b))
for offset := 0; len(a)+len(b) > 0; offset += rowLen {
na, nb := rowLen, rowLen
if na > len(a) {
na = len(a)
}
if nb > len(b) {
nb = len(b)
}
sa := bytestr(offset, a[0:na])
sb := bytestr(offset, b[0:nb])
if sa != sb {
s += fmt.Sprintf("-%v\n+%v\n", sa, sb)
}
a = a[na:]
b = b[nb:]
}
return s
}
func TestWriter(t *testing.T) {
testLoop:
for i, test := range writerTests {
expected, err := ioutil.ReadFile(test.file)
if err != nil {
t.Errorf("test %d: Unexpected error: %v", i, err)
continue
}
buf := new(bytes.Buffer)
tw := NewWriter(iotest.TruncateWriter(buf, 4<<10)) // only catch the first 4 KB
big := false
for j, entry := range test.entries {
big = big || entry.header.Size > 1<<10
if err := tw.WriteHeader(entry.header); err != nil {
t.Errorf("test %d, entry %d: Failed writing header: %v", i, j, err)
continue testLoop
}
if _, err := io.WriteString(tw, entry.contents); err != nil {
t.Errorf("test %d, entry %d: Failed writing contents: %v", i, j, err)
continue testLoop
}
}
// Only interested in Close failures for the small tests.
if err := tw.Close(); err != nil && !big {
t.Errorf("test %d: Failed closing archive: %v", i, err)
continue testLoop
}
actual := buf.Bytes()
if !bytes.Equal(expected, actual) {
t.Errorf("test %d: Incorrect result: (-=expected, +=actual)\n%v",
i, bytediff(expected, actual))
}
if testing.Short() { // The second test is expensive.
break
}
}
}
func TestPax(t *testing.T) {
// Create an archive with a large name
fileinfo, err := os.Stat("testdata/small.txt")
if err != nil {
t.Fatal(err)
}
hdr, err := FileInfoHeader(fileinfo, "")
if err != nil {
t.Fatalf("os.Stat: %v", err)
}
// Force a PAX long name to be written
longName := strings.Repeat("ab", 100)
contents := strings.Repeat(" ", int(hdr.Size))
hdr.Name = longName
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.")) {
t.Fatal("Expected at least one PAX header to be written.")
}
// Test that we can get a long name back out of the archive.
reader := NewReader(&buf)
hdr, err = reader.Next()
if err != nil {
t.Fatal(err)
}
if hdr.Name != longName {
t.Fatal("Couldn't recover long file name")
}
}
func TestPaxSymlink(t *testing.T) {
// Create an archive with a large linkname
fileinfo, err := os.Stat("testdata/small.txt")
if err != nil {
t.Fatal(err)
}
hdr, err := FileInfoHeader(fileinfo, "")
hdr.Typeflag = TypeSymlink
if err != nil {
t.Fatalf("os.Stat:1 %v", err)
}
// Force a PAX long linkname to be written
longLinkname := strings.Repeat("1234567890/1234567890", 10)
hdr.Linkname = longLinkname
hdr.Size = 0
var buf bytes.Buffer
writer := NewWriter(&buf)
if err := writer.WriteHeader(hdr); 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.")) {
t.Fatal("Expected at least one PAX header to be written.")
}
// Test that we can get a long name back out of the archive.
reader := NewReader(&buf)
hdr, err = reader.Next()
if err != nil {
t.Fatal(err)
}
if hdr.Linkname != longLinkname {
t.Fatal("Couldn't recover long link name")
}
}
func TestPaxNonAscii(t *testing.T) {
// Create an archive with non ascii. These should trigger a pax header
// because pax headers have a defined utf-8 encoding.
fileinfo, err := os.Stat("testdata/small.txt")
if err != nil {
t.Fatal(err)
}
hdr, err := FileInfoHeader(fileinfo, "")
if err != nil {
t.Fatalf("os.Stat:1 %v", err)
}
// some sample data
chineseFilename := "文件名"
chineseGroupname := "組"
chineseUsername := "用戶名"
hdr.Name = chineseFilename
hdr.Gname = chineseGroupname
hdr.Uname = chineseUsername
contents := strings.Repeat(" ", int(hdr.Size))
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.")) {
t.Fatal("Expected at least one PAX header to be written.")
}
// Test that we can get a long name back out of the archive.
reader := NewReader(&buf)
hdr, err = reader.Next()
if err != nil {
t.Fatal(err)
}
if hdr.Name != chineseFilename {
t.Fatal("Couldn't recover unicode name")
}
if hdr.Gname != chineseGroupname {
t.Fatal("Couldn't recover unicode group")
}
if hdr.Uname != chineseUsername {
t.Fatal("Couldn't recover unicode user")
}
}
func TestPaxXattrs(t *testing.T) {
xattrs := map[string]string{
"user.key": "value",
}
// Create an archive with an xattr
fileinfo, err := os.Stat("testdata/small.txt")
if err != nil {
t.Fatal(err)
}
hdr, err := FileInfoHeader(fileinfo, "")
if err != nil {
t.Fatalf("os.Stat: %v", err)
}
contents := "Kilts"
hdr.Xattrs = xattrs
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)
}
// Test that we can get the xattrs back out of the archive.
reader := NewReader(&buf)
hdr, err = reader.Next()
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(hdr.Xattrs, xattrs) {
t.Fatalf("xattrs did not survive round trip: got %+v, want %+v",
hdr.Xattrs, xattrs)
}
}
func TestPAXHeader(t *testing.T) {
medName := strings.Repeat("CD", 50)
longName := strings.Repeat("AB", 100)
paxTests := [][2]string{
{paxPath + "=/etc/hosts", "19 path=/etc/hosts\n"},
{"a=b", "6 a=b\n"}, // Single digit length
{"a=names", "11 a=names\n"}, // Test case involving carries
{paxPath + "=" + longName, fmt.Sprintf("210 path=%s\n", longName)},
{paxPath + "=" + medName, fmt.Sprintf("110 path=%s\n", medName)}}
for _, test := range paxTests {
key, expected := test[0], test[1]
if result := paxHeader(key); result != expected {
t.Fatalf("paxHeader: got %s, expected %s", result, expected)
}
}
}
func TestUSTARLongName(t *testing.T) {
// Create an archive with a path that failed to split with USTAR extension in previous versions.
fileinfo, err := os.Stat("testdata/small.txt")
if err != nil {
t.Fatal(err)
}
hdr, err := FileInfoHeader(fileinfo, "")
hdr.Typeflag = TypeDir
if err != nil {
t.Fatalf("os.Stat:1 %v", err)
}
// Force a PAX long name to be written. The name was taken from a practical example
// that fails and replaced ever char through numbers to anonymize the sample.
longName := "/0000_0000000/00000-000000000/0000_0000000/00000-0000000000000/0000_0000000/00000-0000000-00000000/0000_0000000/00000000/0000_0000000/000/0000_0000000/00000000v00/0000_0000000/000000/0000_0000000/0000000/0000_0000000/00000y-00/0000/0000/00000000/0x000000/"
hdr.Name = longName
hdr.Size = 0
var buf bytes.Buffer
writer := NewWriter(&buf)
if err := writer.WriteHeader(hdr); err != nil {
t.Fatal(err)
}
if err := writer.Close(); err != nil {
t.Fatal(err)
}
// Test that we can get a long name back out of the archive.
reader := NewReader(&buf)
hdr, err = reader.Next()
if err != nil {
t.Fatal(err)
}
if hdr.Name != longName {
t.Fatal("Couldn't recover long name")
}
}
func TestValidTypeflagWithPAXHeader(t *testing.T) {
var buffer bytes.Buffer
tw := NewWriter(&buffer)
fileName := strings.Repeat("ab", 100)
hdr := &Header{
Name: fileName,
Size: 4,
Typeflag: 0,
}
if err := tw.WriteHeader(hdr); err != nil {
t.Fatalf("Failed to write header: %s", err)
}
if _, err := tw.Write([]byte("fooo")); err != nil {
t.Fatalf("Failed to write the file's data: %s", err)
}
tw.Close()
tr := NewReader(&buffer)
for {
header, err := tr.Next()
if err == io.EOF {
break
}
if err != nil {
t.Fatalf("Failed to read header: %s", err)
}
if header.Typeflag != 0 {
t.Fatalf("Typeflag should've been 0, found %d", header.Typeflag)
}
}
}