|
|
@@ -4,33 +4,23 @@
|
|
|
|
|
|
package tar
|
|
|
|
|
|
-// TODO(dsymonds):
|
|
|
-// - pax extensions
|
|
|
-
|
|
|
import (
|
|
|
"bytes"
|
|
|
- "errors"
|
|
|
"io"
|
|
|
"io/ioutil"
|
|
|
- "math"
|
|
|
"strconv"
|
|
|
"strings"
|
|
|
"time"
|
|
|
)
|
|
|
|
|
|
-var (
|
|
|
- ErrHeader = errors.New("archive/tar: invalid tar header")
|
|
|
-)
|
|
|
-
|
|
|
-// 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.
|
|
|
+// Reader provides sequential access to the contents of a tar archive.
|
|
|
+// Reader.Next advances to the next file in the archive (including the first),
|
|
|
+// and then Reader can be treated as an io.Reader to access the file's data.
|
|
|
type Reader struct {
|
|
|
r io.Reader
|
|
|
- pad int64 // amount of padding (ignored) after current file entry
|
|
|
- curr numBytesReader // reader for current file entry
|
|
|
- blk block // buffer to use as temporary local storage
|
|
|
+ pad int64 // Amount of padding (ignored) after current file entry
|
|
|
+ curr fileReader // Reader for current file entry
|
|
|
+ blk block // Buffer to use as temporary local storage
|
|
|
|
|
|
// err is a persistent error.
|
|
|
// It is only the responsibility of every exported method of Reader to
|
|
|
@@ -38,68 +28,21 @@ type Reader struct {
|
|
|
err error
|
|
|
}
|
|
|
|
|
|
-// A numBytesReader is an io.Reader with a numBytes method, returning the number
|
|
|
-// of bytes remaining in the underlying encoded data.
|
|
|
-type numBytesReader interface {
|
|
|
+type fileReader interface {
|
|
|
io.Reader
|
|
|
- numBytes() int64
|
|
|
-}
|
|
|
+ fileState
|
|
|
|
|
|
-// 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 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
|
|
|
+ WriteTo(io.Writer) (int64, error)
|
|
|
}
|
|
|
|
|
|
-// 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"
|
|
|
-)
|
|
|
-
|
|
|
// NewReader creates a new Reader reading from r.
|
|
|
-func NewReader(r io.Reader) *Reader { return &Reader{r: r} }
|
|
|
+func NewReader(r io.Reader) *Reader {
|
|
|
+ return &Reader{r: r, curr: ®FileReader{r, 0}}
|
|
|
+}
|
|
|
|
|
|
// Next advances to the next entry in the tar archive.
|
|
|
+// The Header.Size determines how many bytes can be read for the next file.
|
|
|
+// Any remaining data in the current file is automatically discarded.
|
|
|
//
|
|
|
// io.EOF is returned at the end of the input.
|
|
|
func (tr *Reader) Next() (*Header, error) {
|
|
|
@@ -112,18 +55,26 @@ func (tr *Reader) Next() (*Header, error) {
|
|
|
}
|
|
|
|
|
|
func (tr *Reader) next() (*Header, error) {
|
|
|
- var extHdrs map[string]string
|
|
|
+ var paxHdrs map[string]string
|
|
|
+ var gnuLongName, gnuLongLink 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".
|
|
|
+ format := FormatUSTAR | FormatPAX | FormatGNU
|
|
|
loop:
|
|
|
for {
|
|
|
- if err := tr.skipUnread(); err != nil {
|
|
|
+ // Discard the remainder of the file and any padding.
|
|
|
+ if err := discard(tr.r, tr.curr.PhysicalRemaining()); err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
+ if _, err := tryReadFull(tr.r, tr.blk[:tr.pad]); err != nil {
|
|
|
+ return nil, err
|
|
|
+ }
|
|
|
+ tr.pad = 0
|
|
|
+
|
|
|
hdr, rawHdr, err := tr.readHeader()
|
|
|
if err != nil {
|
|
|
return nil, err
|
|
|
@@ -131,43 +82,58 @@ loop:
|
|
|
if err := tr.handleRegularFile(hdr); err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
+ format.mayOnlyBe(hdr.Format)
|
|
|
|
|
|
// Check for PAX/GNU special headers and files.
|
|
|
switch hdr.Typeflag {
|
|
|
- case TypeXHeader:
|
|
|
- extHdrs, err = parsePAX(tr)
|
|
|
+ case TypeXHeader, TypeXGlobalHeader:
|
|
|
+ format.mayOnlyBe(FormatPAX)
|
|
|
+ paxHdrs, err = parsePAX(tr)
|
|
|
if err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
+ if hdr.Typeflag == TypeXGlobalHeader {
|
|
|
+ mergePAX(hdr, paxHdrs)
|
|
|
+ return &Header{
|
|
|
+ Name: hdr.Name,
|
|
|
+ Typeflag: hdr.Typeflag,
|
|
|
+ Xattrs: hdr.Xattrs,
|
|
|
+ PAXRecords: hdr.PAXRecords,
|
|
|
+ Format: format,
|
|
|
+ }, nil
|
|
|
+ }
|
|
|
continue loop // This is a meta header affecting the next header
|
|
|
case TypeGNULongName, TypeGNULongLink:
|
|
|
+ format.mayOnlyBe(FormatGNU)
|
|
|
realname, err := ioutil.ReadAll(tr)
|
|
|
if err != nil {
|
|
|
return nil, 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)
|
|
|
+ gnuLongName = p.parseString(realname)
|
|
|
case TypeGNULongLink:
|
|
|
- extHdrs[paxLinkpath] = p.parseString(realname)
|
|
|
- }
|
|
|
- if p.err != nil {
|
|
|
- return nil, p.err
|
|
|
+ gnuLongLink = p.parseString(realname)
|
|
|
}
|
|
|
continue loop // This is a meta header affecting the next header
|
|
|
default:
|
|
|
// The old GNU sparse format is handled here since it is technically
|
|
|
// just a regular file with additional attributes.
|
|
|
|
|
|
- if err := mergePAX(hdr, extHdrs); err != nil {
|
|
|
+ if err := mergePAX(hdr, paxHdrs); err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
+ if gnuLongName != "" {
|
|
|
+ hdr.Name = gnuLongName
|
|
|
+ }
|
|
|
+ if gnuLongLink != "" {
|
|
|
+ hdr.Linkname = gnuLongLink
|
|
|
+ }
|
|
|
+ if hdr.Typeflag == TypeRegA && strings.HasSuffix(hdr.Name, "/") {
|
|
|
+ hdr.Typeflag = TypeDir // Legacy archives use trailing slash for directories
|
|
|
+ }
|
|
|
|
|
|
// The extended headers may have updated the size.
|
|
|
// Thus, setup the regFileReader again after merging PAX headers.
|
|
|
@@ -177,9 +143,15 @@ loop:
|
|
|
|
|
|
// Sparse formats rely on being able to read from the logical data
|
|
|
// section; there must be a preceding call to handleRegularFile.
|
|
|
- if err := tr.handleSparseFile(hdr, rawHdr, extHdrs); err != nil {
|
|
|
+ if err := tr.handleSparseFile(hdr, rawHdr); err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
+
|
|
|
+ // Set the final guess at the format.
|
|
|
+ if format.has(FormatUSTAR) && format.has(FormatPAX) {
|
|
|
+ format.mayOnlyBe(FormatUSTAR)
|
|
|
+ }
|
|
|
+ hdr.Format = format
|
|
|
return hdr, nil // This is a file, so stop
|
|
|
}
|
|
|
}
|
|
|
@@ -197,105 +169,86 @@ func (tr *Reader) handleRegularFile(hdr *Header) error {
|
|
|
return ErrHeader
|
|
|
}
|
|
|
|
|
|
- tr.pad = -nb & (blockSize - 1) // blockSize is a power of two
|
|
|
+ tr.pad = blockPadding(nb)
|
|
|
tr.curr = ®FileReader{r: tr.r, nb: nb}
|
|
|
return nil
|
|
|
}
|
|
|
|
|
|
// handleSparseFile checks if the current file is a sparse format of any type
|
|
|
// and sets the curr reader appropriately.
|
|
|
-func (tr *Reader) handleSparseFile(hdr *Header, rawHdr *block, extHdrs map[string]string) error {
|
|
|
- var sp []sparseEntry
|
|
|
+func (tr *Reader) handleSparseFile(hdr *Header, rawHdr *block) error {
|
|
|
+ var spd sparseDatas
|
|
|
var err error
|
|
|
if hdr.Typeflag == TypeGNUSparse {
|
|
|
- sp, err = tr.readOldGNUSparseMap(hdr, rawHdr)
|
|
|
- if err != nil {
|
|
|
- return err
|
|
|
- }
|
|
|
+ spd, err = tr.readOldGNUSparseMap(hdr, rawHdr)
|
|
|
} else {
|
|
|
- sp, err = tr.checkForGNUSparsePAXHeaders(hdr, extHdrs)
|
|
|
- if err != nil {
|
|
|
- return err
|
|
|
- }
|
|
|
+ spd, err = tr.readGNUSparsePAXHeaders(hdr)
|
|
|
}
|
|
|
|
|
|
// If sp is non-nil, then this is a sparse file.
|
|
|
- // Note that it is possible for len(sp) to be zero.
|
|
|
- if sp != nil {
|
|
|
- tr.curr, err = newSparseFileReader(tr.curr, sp, hdr.Size)
|
|
|
+ // Note that it is possible for len(sp) == 0.
|
|
|
+ if err == nil && spd != nil {
|
|
|
+ if isHeaderOnlyType(hdr.Typeflag) || !validateSparseEntries(spd, hdr.Size) {
|
|
|
+ return ErrHeader
|
|
|
+ }
|
|
|
+ sph := invertSparseEntries(spd, hdr.Size)
|
|
|
+ tr.curr = &sparseFileReader{tr.curr, sph, 0}
|
|
|
}
|
|
|
return 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, 64)
|
|
|
+// readGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers.
|
|
|
+// If they are found, then this function reads the sparse map and returns it.
|
|
|
+// This assumes that 0.0 headers have already been converted to 0.1 headers
|
|
|
+// by the the PAX header parsing logic.
|
|
|
+func (tr *Reader) readGNUSparsePAXHeaders(hdr *Header) (sparseDatas, error) {
|
|
|
+ // Identify the version of GNU headers.
|
|
|
+ var is1x0 bool
|
|
|
+ major, minor := hdr.PAXRecords[paxGNUSparseMajor], hdr.PAXRecords[paxGNUSparseMinor]
|
|
|
+ switch {
|
|
|
+ case major == "0" && (minor == "0" || minor == "1"):
|
|
|
+ is1x0 = false
|
|
|
+ case major == "1" && minor == "0":
|
|
|
+ is1x0 = true
|
|
|
+ case major != "" || minor != "":
|
|
|
+ return nil, nil // Unknown GNU sparse PAX version
|
|
|
+ case hdr.PAXRecords[paxGNUSparseMap] != "":
|
|
|
+ is1x0 = false // 0.0 and 0.1 did not have explicit version records, so guess
|
|
|
+ default:
|
|
|
+ return nil, nil // Not a PAX format GNU sparse file.
|
|
|
+ }
|
|
|
+ hdr.Format.mayOnlyBe(FormatPAX)
|
|
|
+
|
|
|
+ // Update hdr from GNU sparse PAX headers.
|
|
|
+ if name := hdr.PAXRecords[paxGNUSparseName]; name != "" {
|
|
|
+ hdr.Name = name
|
|
|
+ }
|
|
|
+ size := hdr.PAXRecords[paxGNUSparseSize]
|
|
|
+ if size == "" {
|
|
|
+ size = hdr.PAXRecords[paxGNUSparseRealSize]
|
|
|
+ }
|
|
|
+ if size != "" {
|
|
|
+ n, err := strconv.ParseInt(size, 10, 64)
|
|
|
if err != nil {
|
|
|
return nil, ErrHeader
|
|
|
}
|
|
|
- hdr.Size = realSize
|
|
|
- } else if sparseRealSizeOk {
|
|
|
- realSize, err := strconv.ParseInt(sparseRealSize, 10, 64)
|
|
|
- if err != nil {
|
|
|
- return nil, ErrHeader
|
|
|
- }
|
|
|
- hdr.Size = realSize
|
|
|
+ hdr.Size = n
|
|
|
}
|
|
|
|
|
|
- // 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)
|
|
|
+ // Read the sparse map according to the appropriate format.
|
|
|
+ if is1x0 {
|
|
|
+ return readGNUSparseMap1x0(tr.curr)
|
|
|
}
|
|
|
- return sp, err
|
|
|
+ return readGNUSparseMap0x1(hdr.PAXRecords)
|
|
|
}
|
|
|
|
|
|
-// 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) (err error) {
|
|
|
- var id64 int64
|
|
|
- for k, v := range headers {
|
|
|
+// mergePAX merges paxHdrs into hdr for all relevant fields of Header.
|
|
|
+func mergePAX(hdr *Header, paxHdrs map[string]string) (err error) {
|
|
|
+ for k, v := range paxHdrs {
|
|
|
+ if v == "" {
|
|
|
+ continue // Keep the original USTAR value
|
|
|
+ }
|
|
|
+ var id64 int64
|
|
|
switch k {
|
|
|
case paxPath:
|
|
|
hdr.Name = v
|
|
|
@@ -320,17 +273,18 @@ func mergePAX(hdr *Header, headers map[string]string) (err error) {
|
|
|
case paxSize:
|
|
|
hdr.Size, err = strconv.ParseInt(v, 10, 64)
|
|
|
default:
|
|
|
- if strings.HasPrefix(k, paxXattr) {
|
|
|
+ if strings.HasPrefix(k, paxSchilyXattr) {
|
|
|
if hdr.Xattrs == nil {
|
|
|
hdr.Xattrs = make(map[string]string)
|
|
|
}
|
|
|
- hdr.Xattrs[k[len(paxXattr):]] = v
|
|
|
+ hdr.Xattrs[k[len(paxSchilyXattr):]] = v
|
|
|
}
|
|
|
}
|
|
|
if err != nil {
|
|
|
return ErrHeader
|
|
|
}
|
|
|
}
|
|
|
+ hdr.PAXRecords = paxHdrs
|
|
|
return nil
|
|
|
}
|
|
|
|
|
|
@@ -348,7 +302,7 @@ func parsePAX(r io.Reader) (map[string]string, error) {
|
|
|
// headers since 0.0 headers were not PAX compliant.
|
|
|
var sparseMap []string
|
|
|
|
|
|
- extHdrs := make(map[string]string)
|
|
|
+ paxHdrs := make(map[string]string)
|
|
|
for len(sbuf) > 0 {
|
|
|
key, value, residual, err := parsePAXRecord(sbuf)
|
|
|
if err != nil {
|
|
|
@@ -366,58 +320,13 @@ func parsePAX(r io.Reader) (map[string]string, error) {
|
|
|
}
|
|
|
sparseMap = append(sparseMap, value)
|
|
|
default:
|
|
|
- // According to PAX specification, a value is stored only if it is
|
|
|
- // non-empty. Otherwise, the key is deleted.
|
|
|
- if len(value) > 0 {
|
|
|
- extHdrs[key] = value
|
|
|
- } else {
|
|
|
- delete(extHdrs, key)
|
|
|
- }
|
|
|
+ paxHdrs[key] = value
|
|
|
}
|
|
|
}
|
|
|
if len(sparseMap) > 0 {
|
|
|
- extHdrs[paxGNUSparseMap] = strings.Join(sparseMap, ",")
|
|
|
- }
|
|
|
- return extHdrs, nil
|
|
|
-}
|
|
|
-
|
|
|
-// 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 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, io.SeekCurrent)
|
|
|
- if err == nil {
|
|
|
- // Seek seems supported, so perform the real Seek.
|
|
|
- pos2, err := sr.Seek(dataSkip-1, io.SeekCurrent)
|
|
|
- if err != nil {
|
|
|
- return err
|
|
|
- }
|
|
|
- seekSkipped = pos2 - pos1
|
|
|
- }
|
|
|
+ paxHdrs[paxGNUSparseMap] = strings.Join(sparseMap, ",")
|
|
|
}
|
|
|
-
|
|
|
- copySkipped, err := io.CopyN(ioutil.Discard, tr.r, totalSkip-seekSkipped)
|
|
|
- if err == io.EOF && seekSkipped+copySkipped < dataSkip {
|
|
|
- err = io.ErrUnexpectedEOF
|
|
|
- }
|
|
|
- return err
|
|
|
+ return paxHdrs, nil
|
|
|
}
|
|
|
|
|
|
// readHeader reads the next block header and assumes that the underlying reader
|
|
|
@@ -445,7 +354,7 @@ func (tr *Reader) readHeader() (*Header, *block, error) {
|
|
|
|
|
|
// Verify the header matches a known format.
|
|
|
format := tr.blk.GetFormat()
|
|
|
- if format == formatUnknown {
|
|
|
+ if format == FormatUnknown {
|
|
|
return nil, nil, ErrHeader
|
|
|
}
|
|
|
|
|
|
@@ -454,37 +363,86 @@ func (tr *Reader) readHeader() (*Header, *block, error) {
|
|
|
|
|
|
// Unpack the V7 header.
|
|
|
v7 := tr.blk.V7()
|
|
|
+ hdr.Typeflag = v7.TypeFlag()[0]
|
|
|
hdr.Name = p.parseString(v7.Name())
|
|
|
+ hdr.Linkname = p.parseString(v7.LinkName())
|
|
|
+ hdr.Size = p.parseNumeric(v7.Size())
|
|
|
hdr.Mode = p.parseNumeric(v7.Mode())
|
|
|
hdr.Uid = int(p.parseNumeric(v7.UID()))
|
|
|
hdr.Gid = int(p.parseNumeric(v7.GID()))
|
|
|
- hdr.Size = p.parseNumeric(v7.Size())
|
|
|
hdr.ModTime = time.Unix(p.parseNumeric(v7.ModTime()), 0)
|
|
|
- hdr.Typeflag = v7.TypeFlag()[0]
|
|
|
- hdr.Linkname = p.parseString(v7.LinkName())
|
|
|
|
|
|
// Unpack format specific fields.
|
|
|
if format > formatV7 {
|
|
|
ustar := tr.blk.USTAR()
|
|
|
hdr.Uname = p.parseString(ustar.UserName())
|
|
|
hdr.Gname = p.parseString(ustar.GroupName())
|
|
|
- if hdr.Typeflag == TypeChar || hdr.Typeflag == TypeBlock {
|
|
|
- hdr.Devmajor = p.parseNumeric(ustar.DevMajor())
|
|
|
- hdr.Devminor = p.parseNumeric(ustar.DevMinor())
|
|
|
- }
|
|
|
+ hdr.Devmajor = p.parseNumeric(ustar.DevMajor())
|
|
|
+ hdr.Devminor = p.parseNumeric(ustar.DevMinor())
|
|
|
|
|
|
var prefix string
|
|
|
- switch format {
|
|
|
- case formatUSTAR, formatGNU:
|
|
|
- // TODO(dsnet): Do not use the prefix field for the GNU format!
|
|
|
- // See golang.org/issues/12594
|
|
|
+ switch {
|
|
|
+ case format.has(FormatUSTAR | FormatPAX):
|
|
|
+ hdr.Format = format
|
|
|
ustar := tr.blk.USTAR()
|
|
|
prefix = p.parseString(ustar.Prefix())
|
|
|
- case formatSTAR:
|
|
|
+
|
|
|
+ // For Format detection, check if block is properly formatted since
|
|
|
+ // the parser is more liberal than what USTAR actually permits.
|
|
|
+ notASCII := func(r rune) bool { return r >= 0x80 }
|
|
|
+ if bytes.IndexFunc(tr.blk[:], notASCII) >= 0 {
|
|
|
+ hdr.Format = FormatUnknown // Non-ASCII characters in block.
|
|
|
+ }
|
|
|
+ nul := func(b []byte) bool { return int(b[len(b)-1]) == 0 }
|
|
|
+ if !(nul(v7.Size()) && nul(v7.Mode()) && nul(v7.UID()) && nul(v7.GID()) &&
|
|
|
+ nul(v7.ModTime()) && nul(ustar.DevMajor()) && nul(ustar.DevMinor())) {
|
|
|
+ hdr.Format = FormatUnknown // Numeric fields must end in NUL
|
|
|
+ }
|
|
|
+ case format.has(formatSTAR):
|
|
|
star := tr.blk.STAR()
|
|
|
prefix = p.parseString(star.Prefix())
|
|
|
hdr.AccessTime = time.Unix(p.parseNumeric(star.AccessTime()), 0)
|
|
|
hdr.ChangeTime = time.Unix(p.parseNumeric(star.ChangeTime()), 0)
|
|
|
+ case format.has(FormatGNU):
|
|
|
+ hdr.Format = format
|
|
|
+ var p2 parser
|
|
|
+ gnu := tr.blk.GNU()
|
|
|
+ if b := gnu.AccessTime(); b[0] != 0 {
|
|
|
+ hdr.AccessTime = time.Unix(p2.parseNumeric(b), 0)
|
|
|
+ }
|
|
|
+ if b := gnu.ChangeTime(); b[0] != 0 {
|
|
|
+ hdr.ChangeTime = time.Unix(p2.parseNumeric(b), 0)
|
|
|
+ }
|
|
|
+
|
|
|
+ // Prior to Go1.8, the Writer had a bug where it would output
|
|
|
+ // an invalid tar file in certain rare situations because the logic
|
|
|
+ // incorrectly believed that the old GNU format had a prefix field.
|
|
|
+ // This is wrong and leads to an output file that mangles the
|
|
|
+ // atime and ctime fields, which are often left unused.
|
|
|
+ //
|
|
|
+ // In order to continue reading tar files created by former, buggy
|
|
|
+ // versions of Go, we skeptically parse the atime and ctime fields.
|
|
|
+ // If we are unable to parse them and the prefix field looks like
|
|
|
+ // an ASCII string, then we fallback on the pre-Go1.8 behavior
|
|
|
+ // of treating these fields as the USTAR prefix field.
|
|
|
+ //
|
|
|
+ // Note that this will not use the fallback logic for all possible
|
|
|
+ // files generated by a pre-Go1.8 toolchain. If the generated file
|
|
|
+ // happened to have a prefix field that parses as valid
|
|
|
+ // atime and ctime fields (e.g., when they are valid octal strings),
|
|
|
+ // then it is impossible to distinguish between an valid GNU file
|
|
|
+ // and an invalid pre-Go1.8 file.
|
|
|
+ //
|
|
|
+ // See https://golang.org/issues/12594
|
|
|
+ // See https://golang.org/issues/21005
|
|
|
+ if p2.err != nil {
|
|
|
+ hdr.AccessTime, hdr.ChangeTime = time.Time{}, time.Time{}
|
|
|
+ ustar := tr.blk.USTAR()
|
|
|
+ if s := p.parseString(ustar.Prefix()); isASCII(s) {
|
|
|
+ prefix = s
|
|
|
+ }
|
|
|
+ hdr.Format = FormatUnknown // Buggy file is not GNU
|
|
|
+ }
|
|
|
}
|
|
|
if len(prefix) > 0 {
|
|
|
hdr.Name = prefix + "/" + hdr.Name
|
|
|
@@ -501,21 +459,22 @@ func (tr *Reader) readHeader() (*Header, *block, error) {
|
|
|
// The Header.Size does not reflect the size of any extended headers used.
|
|
|
// Thus, this function will read from the raw io.Reader to fetch extra headers.
|
|
|
// This method mutates blk in the process.
|
|
|
-func (tr *Reader) readOldGNUSparseMap(hdr *Header, blk *block) ([]sparseEntry, error) {
|
|
|
+func (tr *Reader) readOldGNUSparseMap(hdr *Header, blk *block) (sparseDatas, error) {
|
|
|
// Make sure that the input format is GNU.
|
|
|
// Unfortunately, the STAR format also has a sparse header format that uses
|
|
|
// the same type flag but has a completely different layout.
|
|
|
- if blk.GetFormat() != formatGNU {
|
|
|
+ if blk.GetFormat() != FormatGNU {
|
|
|
return nil, ErrHeader
|
|
|
}
|
|
|
+ hdr.Format.mayOnlyBe(FormatGNU)
|
|
|
|
|
|
var p parser
|
|
|
hdr.Size = p.parseNumeric(blk.GNU().RealSize())
|
|
|
if p.err != nil {
|
|
|
return nil, p.err
|
|
|
}
|
|
|
- var s sparseArray = blk.GNU().Sparse()
|
|
|
- var sp = make([]sparseEntry, 0, s.MaxEntries())
|
|
|
+ s := blk.GNU().Sparse()
|
|
|
+ spd := make(sparseDatas, 0, s.MaxEntries())
|
|
|
for {
|
|
|
for i := 0; i < s.MaxEntries(); i++ {
|
|
|
// This termination condition is identical to GNU and BSD tar.
|
|
|
@@ -523,25 +482,22 @@ func (tr *Reader) readOldGNUSparseMap(hdr *Header, blk *block) ([]sparseEntry, e
|
|
|
break // Don't return, need to process extended headers (even if empty)
|
|
|
}
|
|
|
offset := p.parseNumeric(s.Entry(i).Offset())
|
|
|
- numBytes := p.parseNumeric(s.Entry(i).NumBytes())
|
|
|
+ length := p.parseNumeric(s.Entry(i).Length())
|
|
|
if p.err != nil {
|
|
|
return nil, p.err
|
|
|
}
|
|
|
- sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
|
|
|
+ spd = append(spd, sparseEntry{Offset: offset, Length: length})
|
|
|
}
|
|
|
|
|
|
if s.IsExtended()[0] > 0 {
|
|
|
// There are more entries. Read an extension header and parse its entries.
|
|
|
- if _, err := io.ReadFull(tr.r, blk[:]); err != nil {
|
|
|
- if err == io.EOF {
|
|
|
- err = io.ErrUnexpectedEOF
|
|
|
- }
|
|
|
+ if _, err := mustReadFull(tr.r, blk[:]); err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
s = blk.Sparse()
|
|
|
continue
|
|
|
}
|
|
|
- return sp, nil // Done
|
|
|
+ return spd, nil // Done
|
|
|
}
|
|
|
}
|
|
|
|
|
|
@@ -549,28 +505,27 @@ func (tr *Reader) readOldGNUSparseMap(hdr *Header, blk *block) ([]sparseEntry, e
|
|
|
// 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
|
|
|
+// fields (offset, length). This function must stop reading at the end
|
|
|
// boundary of the block containing the last newline.
|
|
|
//
|
|
|
// Note that the GNU manual says that numeric values should be encoded in octal
|
|
|
// format. However, the GNU tar utility itself outputs these values in decimal.
|
|
|
// As such, this library treats values as being encoded in decimal.
|
|
|
-func readGNUSparseMap1x0(r io.Reader) ([]sparseEntry, error) {
|
|
|
- var cntNewline int64
|
|
|
- var buf bytes.Buffer
|
|
|
- var blk = make([]byte, blockSize)
|
|
|
-
|
|
|
- // feedTokens copies data in numBlock chunks from r into buf until there are
|
|
|
+func readGNUSparseMap1x0(r io.Reader) (sparseDatas, error) {
|
|
|
+ var (
|
|
|
+ cntNewline int64
|
|
|
+ buf bytes.Buffer
|
|
|
+ blk block
|
|
|
+ )
|
|
|
+
|
|
|
+ // feedTokens copies data in blocks 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
|
|
|
- }
|
|
|
+ feedTokens := func(n int64) error {
|
|
|
+ for cntNewline < n {
|
|
|
+ if _, err := mustReadFull(r, blk[:]); err != nil {
|
|
|
return err
|
|
|
}
|
|
|
- buf.Write(blk)
|
|
|
+ buf.Write(blk[:])
|
|
|
for _, c := range blk {
|
|
|
if c == '\n' {
|
|
|
cntNewline++
|
|
|
@@ -582,10 +537,10 @@ func readGNUSparseMap1x0(r io.Reader) ([]sparseEntry, error) {
|
|
|
|
|
|
// nextToken gets the next token delimited by a newline. This assumes that
|
|
|
// at least one newline exists in the buffer.
|
|
|
- var nextToken = func() string {
|
|
|
+ nextToken := func() string {
|
|
|
cntNewline--
|
|
|
tok, _ := buf.ReadString('\n')
|
|
|
- return tok[:len(tok)-1] // Cut off newline
|
|
|
+ return strings.TrimRight(tok, "\n")
|
|
|
}
|
|
|
|
|
|
// Parse for the number of entries.
|
|
|
@@ -604,80 +559,67 @@ func readGNUSparseMap1x0(r io.Reader) ([]sparseEntry, error) {
|
|
|
if err := feedTokens(2 * numEntries); err != nil {
|
|
|
return nil, err
|
|
|
}
|
|
|
- sp := make([]sparseEntry, 0, numEntries)
|
|
|
+ spd := make(sparseDatas, 0, numEntries)
|
|
|
for i := int64(0); i < numEntries; i++ {
|
|
|
- offset, err := strconv.ParseInt(nextToken(), 10, 64)
|
|
|
- if err != nil {
|
|
|
+ offset, err1 := strconv.ParseInt(nextToken(), 10, 64)
|
|
|
+ length, err2 := strconv.ParseInt(nextToken(), 10, 64)
|
|
|
+ if err1 != nil || err2 != nil {
|
|
|
return nil, ErrHeader
|
|
|
}
|
|
|
- numBytes, err := strconv.ParseInt(nextToken(), 10, 64)
|
|
|
- if err != nil {
|
|
|
- return nil, ErrHeader
|
|
|
- }
|
|
|
- sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
|
|
|
+ spd = append(spd, sparseEntry{Offset: offset, Length: length})
|
|
|
}
|
|
|
- return sp, nil
|
|
|
+ return spd, 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) {
|
|
|
+func readGNUSparseMap0x1(paxHdrs map[string]string) (sparseDatas, error) {
|
|
|
// Get number of entries.
|
|
|
// Use integer overflow resistant math to check this.
|
|
|
- numEntriesStr := extHdrs[paxGNUSparseNumBlocks]
|
|
|
+ numEntriesStr := paxHdrs[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
|
|
|
}
|
|
|
|
|
|
// There should be two numbers in sparseMap for each entry.
|
|
|
- sparseMap := strings.Split(extHdrs[paxGNUSparseMap], ",")
|
|
|
+ sparseMap := strings.Split(paxHdrs[paxGNUSparseMap], ",")
|
|
|
+ if len(sparseMap) == 1 && sparseMap[0] == "" {
|
|
|
+ sparseMap = sparseMap[:0]
|
|
|
+ }
|
|
|
if int64(len(sparseMap)) != 2*numEntries {
|
|
|
return nil, ErrHeader
|
|
|
}
|
|
|
|
|
|
// Loop through the entries in the sparse map.
|
|
|
// numEntries is trusted now.
|
|
|
- sp := make([]sparseEntry, 0, numEntries)
|
|
|
- for i := int64(0); i < numEntries; i++ {
|
|
|
- offset, err := strconv.ParseInt(sparseMap[2*i], 10, 64)
|
|
|
- if err != nil {
|
|
|
- return nil, ErrHeader
|
|
|
- }
|
|
|
- numBytes, err := strconv.ParseInt(sparseMap[2*i+1], 10, 64)
|
|
|
- if err != nil {
|
|
|
+ spd := make(sparseDatas, 0, numEntries)
|
|
|
+ for len(sparseMap) >= 2 {
|
|
|
+ offset, err1 := strconv.ParseInt(sparseMap[0], 10, 64)
|
|
|
+ length, err2 := strconv.ParseInt(sparseMap[1], 10, 64)
|
|
|
+ if err1 != nil || err2 != nil {
|
|
|
return nil, ErrHeader
|
|
|
}
|
|
|
- sp = append(sp, sparseEntry{offset: offset, numBytes: numBytes})
|
|
|
+ spd = append(spd, sparseEntry{Offset: offset, Length: length})
|
|
|
+ sparseMap = sparseMap[2:]
|
|
|
}
|
|
|
- return sp, nil
|
|
|
+ return spd, 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.
|
|
|
+// Read reads from the current file in the tar archive.
|
|
|
+// It returns (0, io.EOF) when it reaches the end of that file,
|
|
|
+// until Next is called to advance to the next file.
|
|
|
+//
|
|
|
+// If the current file is sparse, then the regions marked as a hole
|
|
|
+// are read back as NUL-bytes.
|
|
|
//
|
|
|
-// Calling Read on special types like TypeLink, TypeSymLink, TypeChar,
|
|
|
-// TypeBlock, TypeDir, and TypeFifo returns 0, io.EOF regardless of what
|
|
|
+// 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) (int, 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
|
|
|
@@ -685,116 +627,229 @@ func (tr *Reader) Read(b []byte) (int, error) {
|
|
|
return n, err
|
|
|
}
|
|
|
|
|
|
-func (rfr *regFileReader) Read(b []byte) (n int, err error) {
|
|
|
- if rfr.nb == 0 {
|
|
|
- // file consumed
|
|
|
- return 0, io.EOF
|
|
|
+// writeTo writes the content of the current file to w.
|
|
|
+// The bytes written matches the number of remaining bytes in the current file.
|
|
|
+//
|
|
|
+// If the current file is sparse and w is an io.WriteSeeker,
|
|
|
+// then writeTo uses Seek to skip past holes defined in Header.SparseHoles,
|
|
|
+// assuming that skipped regions are filled with NULs.
|
|
|
+// This always writes the last byte to ensure w is the right size.
|
|
|
+//
|
|
|
+// TODO(dsnet): Re-export this when adding sparse file support.
|
|
|
+// See https://golang.org/issue/22735
|
|
|
+func (tr *Reader) writeTo(w io.Writer) (int64, error) {
|
|
|
+ if tr.err != nil {
|
|
|
+ return 0, tr.err
|
|
|
}
|
|
|
- if int64(len(b)) > rfr.nb {
|
|
|
- b = b[0:rfr.nb]
|
|
|
+ n, err := tr.curr.WriteTo(w)
|
|
|
+ if err != nil {
|
|
|
+ tr.err = err
|
|
|
}
|
|
|
- n, err = rfr.r.Read(b)
|
|
|
- rfr.nb -= int64(n)
|
|
|
+ return n, err
|
|
|
+}
|
|
|
|
|
|
- if err == io.EOF && rfr.nb > 0 {
|
|
|
- err = io.ErrUnexpectedEOF
|
|
|
+// regFileReader is a fileReader for reading data from a regular file entry.
|
|
|
+type regFileReader struct {
|
|
|
+ r io.Reader // Underlying Reader
|
|
|
+ nb int64 // Number of remaining bytes to read
|
|
|
+}
|
|
|
+
|
|
|
+func (fr *regFileReader) Read(b []byte) (n int, err error) {
|
|
|
+ if int64(len(b)) > fr.nb {
|
|
|
+ b = b[:fr.nb]
|
|
|
+ }
|
|
|
+ if len(b) > 0 {
|
|
|
+ n, err = fr.r.Read(b)
|
|
|
+ fr.nb -= int64(n)
|
|
|
+ }
|
|
|
+ switch {
|
|
|
+ case err == io.EOF && fr.nb > 0:
|
|
|
+ return n, io.ErrUnexpectedEOF
|
|
|
+ case err == nil && fr.nb == 0:
|
|
|
+ return n, io.EOF
|
|
|
+ default:
|
|
|
+ return n, err
|
|
|
}
|
|
|
- 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
|
|
|
+func (fr *regFileReader) WriteTo(w io.Writer) (int64, error) {
|
|
|
+ return io.Copy(w, struct{ io.Reader }{fr})
|
|
|
}
|
|
|
|
|
|
-// 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
|
|
|
- }
|
|
|
+func (fr regFileReader) LogicalRemaining() int64 {
|
|
|
+ return fr.nb
|
|
|
+}
|
|
|
|
|
|
- // 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
|
|
|
+func (fr regFileReader) PhysicalRemaining() int64 {
|
|
|
+ return fr.nb
|
|
|
}
|
|
|
|
|
|
-// 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))
|
|
|
+// sparseFileReader is a fileReader for reading data from a sparse file entry.
|
|
|
+type sparseFileReader struct {
|
|
|
+ fr fileReader // Underlying fileReader
|
|
|
+ sp sparseHoles // Normalized list of sparse holes
|
|
|
+ pos int64 // Current position in sparse file
|
|
|
+}
|
|
|
+
|
|
|
+func (sr *sparseFileReader) Read(b []byte) (n int, err error) {
|
|
|
+ finished := int64(len(b)) >= sr.LogicalRemaining()
|
|
|
+ if finished {
|
|
|
+ b = b[:sr.LogicalRemaining()]
|
|
|
+ }
|
|
|
+
|
|
|
+ b0 := b
|
|
|
+ endPos := sr.pos + int64(len(b))
|
|
|
+ for endPos > sr.pos && err == nil {
|
|
|
+ var nf int // Bytes read in fragment
|
|
|
+ holeStart, holeEnd := sr.sp[0].Offset, sr.sp[0].endOffset()
|
|
|
+ if sr.pos < holeStart { // In a data fragment
|
|
|
+ bf := b[:min(int64(len(b)), holeStart-sr.pos)]
|
|
|
+ nf, err = tryReadFull(sr.fr, bf)
|
|
|
+ } else { // In a hole fragment
|
|
|
+ bf := b[:min(int64(len(b)), holeEnd-sr.pos)]
|
|
|
+ nf, err = tryReadFull(zeroReader{}, bf)
|
|
|
+ }
|
|
|
+ b = b[nf:]
|
|
|
+ sr.pos += int64(nf)
|
|
|
+ if sr.pos >= holeEnd && len(sr.sp) > 1 {
|
|
|
+ sr.sp = sr.sp[1:] // Ensure last fragment always remains
|
|
|
+ }
|
|
|
}
|
|
|
- n := int(n64)
|
|
|
- for i := 0; i < n; i++ {
|
|
|
- b[i] = 0
|
|
|
+
|
|
|
+ n = len(b0) - len(b)
|
|
|
+ switch {
|
|
|
+ case err == io.EOF:
|
|
|
+ return n, errMissData // Less data in dense file than sparse file
|
|
|
+ case err != nil:
|
|
|
+ return n, err
|
|
|
+ case sr.LogicalRemaining() == 0 && sr.PhysicalRemaining() > 0:
|
|
|
+ return n, errUnrefData // More data in dense file than sparse file
|
|
|
+ case finished:
|
|
|
+ return n, io.EOF
|
|
|
+ default:
|
|
|
+ return n, nil
|
|
|
}
|
|
|
- sfr.pos += n64
|
|
|
- return n
|
|
|
}
|
|
|
|
|
|
-// Read reads the sparse file data in expanded form.
|
|
|
-func (sfr *sparseFileReader) Read(b []byte) (n int, err error) {
|
|
|
- // Skip past all empty fragments.
|
|
|
- for len(sfr.sp) > 0 && sfr.sp[0].numBytes == 0 {
|
|
|
- sfr.sp = sfr.sp[1:]
|
|
|
+func (sr *sparseFileReader) WriteTo(w io.Writer) (n int64, err error) {
|
|
|
+ ws, ok := w.(io.WriteSeeker)
|
|
|
+ if ok {
|
|
|
+ if _, err := ws.Seek(0, io.SeekCurrent); err != nil {
|
|
|
+ ok = false // Not all io.Seeker can really seek
|
|
|
+ }
|
|
|
}
|
|
|
-
|
|
|
- // 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
|
|
|
+ if !ok {
|
|
|
+ return io.Copy(w, struct{ io.Reader }{sr})
|
|
|
+ }
|
|
|
+
|
|
|
+ var writeLastByte bool
|
|
|
+ pos0 := sr.pos
|
|
|
+ for sr.LogicalRemaining() > 0 && !writeLastByte && err == nil {
|
|
|
+ var nf int64 // Size of fragment
|
|
|
+ holeStart, holeEnd := sr.sp[0].Offset, sr.sp[0].endOffset()
|
|
|
+ if sr.pos < holeStart { // In a data fragment
|
|
|
+ nf = holeStart - sr.pos
|
|
|
+ nf, err = io.CopyN(ws, sr.fr, nf)
|
|
|
+ } else { // In a hole fragment
|
|
|
+ nf = holeEnd - sr.pos
|
|
|
+ if sr.PhysicalRemaining() == 0 {
|
|
|
+ writeLastByte = true
|
|
|
+ nf--
|
|
|
+ }
|
|
|
+ _, err = ws.Seek(nf, io.SeekCurrent)
|
|
|
+ }
|
|
|
+ sr.pos += nf
|
|
|
+ if sr.pos >= holeEnd && len(sr.sp) > 1 {
|
|
|
+ sr.sp = sr.sp[1:] // Ensure last fragment always remains
|
|
|
}
|
|
|
- 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
|
|
|
+ // If the last fragment is a hole, then seek to 1-byte before EOF, and
|
|
|
+ // write a single byte to ensure the file is the right size.
|
|
|
+ if writeLastByte && err == nil {
|
|
|
+ _, err = ws.Write([]byte{0})
|
|
|
+ sr.pos++
|
|
|
}
|
|
|
|
|
|
- // 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[:bytesLeft]
|
|
|
+ n = sr.pos - pos0
|
|
|
+ switch {
|
|
|
+ case err == io.EOF:
|
|
|
+ return n, errMissData // Less data in dense file than sparse file
|
|
|
+ case err != nil:
|
|
|
+ return n, err
|
|
|
+ case sr.LogicalRemaining() == 0 && sr.PhysicalRemaining() > 0:
|
|
|
+ return n, errUnrefData // More data in dense file than sparse file
|
|
|
+ default:
|
|
|
+ return n, nil
|
|
|
}
|
|
|
+}
|
|
|
|
|
|
- n, err = sfr.rfr.Read(b)
|
|
|
- sfr.pos += int64(n)
|
|
|
+func (sr sparseFileReader) LogicalRemaining() int64 {
|
|
|
+ return sr.sp[len(sr.sp)-1].endOffset() - sr.pos
|
|
|
+}
|
|
|
+func (sr sparseFileReader) PhysicalRemaining() int64 {
|
|
|
+ return sr.fr.PhysicalRemaining()
|
|
|
+}
|
|
|
+
|
|
|
+type zeroReader struct{}
|
|
|
+
|
|
|
+func (zeroReader) Read(b []byte) (int, error) {
|
|
|
+ for i := range b {
|
|
|
+ b[i] = 0
|
|
|
+ }
|
|
|
+ return len(b), nil
|
|
|
+}
|
|
|
+
|
|
|
+// mustReadFull is like io.ReadFull except it returns
|
|
|
+// io.ErrUnexpectedEOF when io.EOF is hit before len(b) bytes are read.
|
|
|
+func mustReadFull(r io.Reader, b []byte) (int, error) {
|
|
|
+ n, err := tryReadFull(r, b)
|
|
|
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
|
|
|
- }
|
|
|
+ err = io.ErrUnexpectedEOF
|
|
|
}
|
|
|
+ return n, err
|
|
|
+}
|
|
|
|
|
|
- if sfr.pos == endPos {
|
|
|
- sfr.sp = sfr.sp[1:] // We are done with this fragment, so pop it
|
|
|
+// tryReadFull is like io.ReadFull except it returns
|
|
|
+// io.EOF when it is hit before len(b) bytes are read.
|
|
|
+func tryReadFull(r io.Reader, b []byte) (n int, err error) {
|
|
|
+ for len(b) > n && err == nil {
|
|
|
+ var nn int
|
|
|
+ nn, err = r.Read(b[n:])
|
|
|
+ n += nn
|
|
|
+ }
|
|
|
+ if len(b) == n && err == io.EOF {
|
|
|
+ err = nil
|
|
|
}
|
|
|
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.numBytes()
|
|
|
+// discard skips n bytes in r, reporting an error if unable to do so.
|
|
|
+func discard(r io.Reader, n int64) error {
|
|
|
+ // 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 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 := r.(io.Seeker); ok && n > 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, io.SeekCurrent)
|
|
|
+ if pos1 >= 0 && err == nil {
|
|
|
+ // Seek seems supported, so perform the real Seek.
|
|
|
+ pos2, err := sr.Seek(n-1, io.SeekCurrent)
|
|
|
+ if pos2 < 0 || err != nil {
|
|
|
+ return err
|
|
|
+ }
|
|
|
+ seekSkipped = pos2 - pos1
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ copySkipped, err := io.CopyN(ioutil.Discard, r, n-seekSkipped)
|
|
|
+ if err == io.EOF && seekSkipped+copySkipped < n {
|
|
|
+ err = io.ErrUnexpectedEOF
|
|
|
+ }
|
|
|
+ return err
|
|
|
}
|
Tibor Vass