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@@ -1,820 +0,0 @@
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-// Copyright 2009 The Go Authors. All rights reserved.
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-// Use of this source code is governed by a BSD-style
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-// license that can be found in the LICENSE file.
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-
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-package tar
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-
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-// TODO(dsymonds):
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-// - pax extensions
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-
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-import (
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- "bytes"
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- "errors"
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- "io"
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- "io/ioutil"
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- "os"
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- "strconv"
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- "strings"
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- "time"
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-)
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-
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-var (
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- ErrHeader = errors.New("archive/tar: invalid tar header")
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-)
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-
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-const maxNanoSecondIntSize = 9
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-
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-// A Reader provides sequential access to the contents of a tar archive.
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-// A tar archive consists of a sequence of files.
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-// The Next method advances to the next file in the archive (including the first),
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-// and then it can be treated as an io.Reader to access the file's data.
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-type Reader struct {
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- r io.Reader
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- err error
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- pad int64 // amount of padding (ignored) after current file entry
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- curr numBytesReader // reader for current file entry
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- hdrBuff [blockSize]byte // buffer to use in readHeader
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-}
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-
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-// A numBytesReader is an io.Reader with a numBytes method, returning the number
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-// of bytes remaining in the underlying encoded data.
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-type numBytesReader interface {
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- io.Reader
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- numBytes() int64
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-}
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-
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-// A regFileReader is a numBytesReader for reading file data from a tar archive.
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-type regFileReader struct {
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- r io.Reader // underlying reader
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- nb int64 // number of unread bytes for current file entry
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-}
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-
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-// A sparseFileReader is a numBytesReader for reading sparse file data from a tar archive.
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-type sparseFileReader struct {
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- rfr *regFileReader // reads the sparse-encoded file data
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- sp []sparseEntry // the sparse map for the file
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- pos int64 // keeps track of file position
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- tot int64 // total size of the file
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-}
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-
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-// Keywords for GNU sparse files in a PAX extended header
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-const (
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- paxGNUSparseNumBlocks = "GNU.sparse.numblocks"
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- paxGNUSparseOffset = "GNU.sparse.offset"
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- paxGNUSparseNumBytes = "GNU.sparse.numbytes"
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- paxGNUSparseMap = "GNU.sparse.map"
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- paxGNUSparseName = "GNU.sparse.name"
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- paxGNUSparseMajor = "GNU.sparse.major"
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- paxGNUSparseMinor = "GNU.sparse.minor"
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- paxGNUSparseSize = "GNU.sparse.size"
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- paxGNUSparseRealSize = "GNU.sparse.realsize"
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-)
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-
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-// Keywords for old GNU sparse headers
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-const (
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- oldGNUSparseMainHeaderOffset = 386
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- oldGNUSparseMainHeaderIsExtendedOffset = 482
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- oldGNUSparseMainHeaderNumEntries = 4
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- oldGNUSparseExtendedHeaderIsExtendedOffset = 504
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- oldGNUSparseExtendedHeaderNumEntries = 21
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- oldGNUSparseOffsetSize = 12
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- oldGNUSparseNumBytesSize = 12
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-)
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-
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-// NewReader creates a new Reader reading from r.
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-func NewReader(r io.Reader) *Reader { return &Reader{r: r} }
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-
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-// Next advances to the next entry in the tar archive.
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-func (tr *Reader) Next() (*Header, error) {
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- var hdr *Header
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- if tr.err == nil {
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- tr.skipUnread()
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- }
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- if tr.err != nil {
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- return hdr, tr.err
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- }
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- hdr = tr.readHeader()
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- if hdr == nil {
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- return hdr, tr.err
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- }
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- // Check for PAX/GNU header.
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- switch hdr.Typeflag {
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- case TypeXHeader:
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- // PAX extended header
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- headers, err := parsePAX(tr)
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- if err != nil {
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- return nil, err
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- }
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- // We actually read the whole file,
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- // but this skips alignment padding
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- tr.skipUnread()
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- hdr = tr.readHeader()
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- mergePAX(hdr, headers)
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-
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- // Check for a PAX format sparse file
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- sp, err := tr.checkForGNUSparsePAXHeaders(hdr, headers)
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- if err != nil {
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- tr.err = err
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- return nil, err
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- }
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- if sp != nil {
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- // Current file is a PAX format GNU sparse file.
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- // Set the current file reader to a sparse file reader.
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- tr.curr = &sparseFileReader{rfr: tr.curr.(*regFileReader), sp: sp, tot: hdr.Size}
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- }
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- return hdr, nil
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- case TypeGNULongName:
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- // We have a GNU long name header. Its contents are the real file name.
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- realname, err := ioutil.ReadAll(tr)
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- if err != nil {
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- return nil, err
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- }
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- hdr, err := tr.Next()
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- hdr.Name = cString(realname)
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- return hdr, err
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- case TypeGNULongLink:
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- // We have a GNU long link header.
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- realname, err := ioutil.ReadAll(tr)
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- if err != nil {
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- return nil, err
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- }
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- hdr, err := tr.Next()
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- hdr.Linkname = cString(realname)
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- return hdr, err
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- }
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- return hdr, tr.err
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-}
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-
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-// checkForGNUSparsePAXHeaders checks the PAX headers for GNU sparse headers. If they are found, then
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-// this function reads the sparse map and returns it. Unknown sparse formats are ignored, causing the file to
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-// be treated as a regular file.
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-func (tr *Reader) checkForGNUSparsePAXHeaders(hdr *Header, headers map[string]string) ([]sparseEntry, error) {
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- var sparseFormat string
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-
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- // Check for sparse format indicators
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- major, majorOk := headers[paxGNUSparseMajor]
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- minor, minorOk := headers[paxGNUSparseMinor]
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- sparseName, sparseNameOk := headers[paxGNUSparseName]
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- _, sparseMapOk := headers[paxGNUSparseMap]
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- sparseSize, sparseSizeOk := headers[paxGNUSparseSize]
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- sparseRealSize, sparseRealSizeOk := headers[paxGNUSparseRealSize]
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-
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- // Identify which, if any, sparse format applies from which PAX headers are set
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- if majorOk && minorOk {
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- sparseFormat = major + "." + minor
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- } else if sparseNameOk && sparseMapOk {
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- sparseFormat = "0.1"
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- } else if sparseSizeOk {
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- sparseFormat = "0.0"
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- } else {
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- // Not a PAX format GNU sparse file.
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- return nil, nil
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- }
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-
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- // Check for unknown sparse format
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- if sparseFormat != "0.0" && sparseFormat != "0.1" && sparseFormat != "1.0" {
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- return nil, nil
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- }
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-
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- // Update hdr from GNU sparse PAX headers
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- if sparseNameOk {
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- hdr.Name = sparseName
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- }
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- if sparseSizeOk {
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- realSize, err := strconv.ParseInt(sparseSize, 10, 0)
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- if err != nil {
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- return nil, ErrHeader
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- }
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- hdr.Size = realSize
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- } else if sparseRealSizeOk {
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- realSize, err := strconv.ParseInt(sparseRealSize, 10, 0)
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- if err != nil {
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- return nil, ErrHeader
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- }
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- hdr.Size = realSize
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- }
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-
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- // Set up the sparse map, according to the particular sparse format in use
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- var sp []sparseEntry
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- var err error
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- switch sparseFormat {
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- case "0.0", "0.1":
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- sp, err = readGNUSparseMap0x1(headers)
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- case "1.0":
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- sp, err = readGNUSparseMap1x0(tr.curr)
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- }
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- return sp, err
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-}
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-
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-// mergePAX merges well known headers according to PAX standard.
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-// In general headers with the same name as those found
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-// in the header struct overwrite those found in the header
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-// struct with higher precision or longer values. Esp. useful
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-// for name and linkname fields.
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-func mergePAX(hdr *Header, headers map[string]string) error {
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- for k, v := range headers {
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- switch k {
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- case paxPath:
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- hdr.Name = v
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- case paxLinkpath:
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- hdr.Linkname = v
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- case paxGname:
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- hdr.Gname = v
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- case paxUname:
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- hdr.Uname = v
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- case paxUid:
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- uid, err := strconv.ParseInt(v, 10, 0)
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- if err != nil {
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- return err
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- }
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- hdr.Uid = int(uid)
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- case paxGid:
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- gid, err := strconv.ParseInt(v, 10, 0)
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- if err != nil {
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- return err
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- }
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- hdr.Gid = int(gid)
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- case paxAtime:
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- t, err := parsePAXTime(v)
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- if err != nil {
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- return err
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- }
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- hdr.AccessTime = t
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- case paxMtime:
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- t, err := parsePAXTime(v)
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- if err != nil {
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- return err
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- }
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- hdr.ModTime = t
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- case paxCtime:
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- t, err := parsePAXTime(v)
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- if err != nil {
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- return err
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- }
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- hdr.ChangeTime = t
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- case paxSize:
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- size, err := strconv.ParseInt(v, 10, 0)
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- if err != nil {
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- return err
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- }
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- hdr.Size = int64(size)
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- default:
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- if strings.HasPrefix(k, paxXattr) {
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- if hdr.Xattrs == nil {
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- hdr.Xattrs = make(map[string]string)
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- }
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- hdr.Xattrs[k[len(paxXattr):]] = v
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- }
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- }
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- }
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- return nil
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-}
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-
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-// parsePAXTime takes a string of the form %d.%d as described in
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-// the PAX specification.
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-func parsePAXTime(t string) (time.Time, error) {
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- buf := []byte(t)
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- pos := bytes.IndexByte(buf, '.')
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- var seconds, nanoseconds int64
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- var err error
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- if pos == -1 {
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- seconds, err = strconv.ParseInt(t, 10, 0)
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- if err != nil {
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- return time.Time{}, err
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- }
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- } else {
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- seconds, err = strconv.ParseInt(string(buf[:pos]), 10, 0)
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- if err != nil {
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- return time.Time{}, err
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- }
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- nano_buf := string(buf[pos+1:])
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- // Pad as needed before converting to a decimal.
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- // For example .030 -> .030000000 -> 30000000 nanoseconds
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- if len(nano_buf) < maxNanoSecondIntSize {
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- // Right pad
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- nano_buf += strings.Repeat("0", maxNanoSecondIntSize-len(nano_buf))
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- } else if len(nano_buf) > maxNanoSecondIntSize {
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- // Right truncate
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- nano_buf = nano_buf[:maxNanoSecondIntSize]
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- }
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- nanoseconds, err = strconv.ParseInt(string(nano_buf), 10, 0)
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- if err != nil {
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- return time.Time{}, err
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- }
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- }
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- ts := time.Unix(seconds, nanoseconds)
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- return ts, nil
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-}
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-
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-// parsePAX parses PAX headers.
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-// If an extended header (type 'x') is invalid, ErrHeader is returned
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-func parsePAX(r io.Reader) (map[string]string, error) {
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- buf, err := ioutil.ReadAll(r)
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- if err != nil {
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- return nil, err
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- }
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-
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- // For GNU PAX sparse format 0.0 support.
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- // This function transforms the sparse format 0.0 headers into sparse format 0.1 headers.
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- var sparseMap bytes.Buffer
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-
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- headers := make(map[string]string)
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- // Each record is constructed as
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- // "%d %s=%s\n", length, keyword, value
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- for len(buf) > 0 {
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- // or the header was empty to start with.
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- var sp int
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- // The size field ends at the first space.
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- sp = bytes.IndexByte(buf, ' ')
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- if sp == -1 {
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- return nil, ErrHeader
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- }
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- // Parse the first token as a decimal integer.
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- n, err := strconv.ParseInt(string(buf[:sp]), 10, 0)
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- if err != nil {
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- return nil, ErrHeader
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- }
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- // Extract everything between the decimal and the n -1 on the
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- // beginning to eat the ' ', -1 on the end to skip the newline.
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- var record []byte
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- record, buf = buf[sp+1:n-1], buf[n:]
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- // The first equals is guaranteed to mark the end of the key.
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- // Everything else is value.
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- eq := bytes.IndexByte(record, '=')
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- if eq == -1 {
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- return nil, ErrHeader
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- }
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- key, value := record[:eq], record[eq+1:]
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-
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- keyStr := string(key)
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- if keyStr == paxGNUSparseOffset || keyStr == paxGNUSparseNumBytes {
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- // GNU sparse format 0.0 special key. Write to sparseMap instead of using the headers map.
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- sparseMap.Write(value)
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- sparseMap.Write([]byte{','})
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- } else {
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- // Normal key. Set the value in the headers map.
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- headers[keyStr] = string(value)
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- }
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- }
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- if sparseMap.Len() != 0 {
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- // Add sparse info to headers, chopping off the extra comma
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- sparseMap.Truncate(sparseMap.Len() - 1)
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- headers[paxGNUSparseMap] = sparseMap.String()
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- }
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- return headers, nil
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-}
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-
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-// cString parses bytes as a NUL-terminated C-style string.
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-// If a NUL byte is not found then the whole slice is returned as a string.
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-func cString(b []byte) string {
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- n := 0
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- for n < len(b) && b[n] != 0 {
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- n++
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- }
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- return string(b[0:n])
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-}
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-
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-func (tr *Reader) octal(b []byte) int64 {
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- // Check for binary format first.
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- if len(b) > 0 && b[0]&0x80 != 0 {
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- var x int64
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- for i, c := range b {
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- if i == 0 {
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- c &= 0x7f // ignore signal bit in first byte
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- }
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- x = x<<8 | int64(c)
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- }
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- return x
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- }
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-
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- // Because unused fields are filled with NULs, we need
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- // to skip leading NULs. Fields may also be padded with
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- // spaces or NULs.
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- // So we remove leading and trailing NULs and spaces to
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- // be sure.
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- b = bytes.Trim(b, " \x00")
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-
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- if len(b) == 0 {
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- return 0
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- }
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- x, err := strconv.ParseUint(cString(b), 8, 64)
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- if err != nil {
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- tr.err = err
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- }
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- return int64(x)
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-}
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-
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-// skipUnread skips any unread bytes in the existing file entry, as well as any alignment padding.
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-func (tr *Reader) skipUnread() {
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- nr := tr.numBytes() + tr.pad // number of bytes to skip
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- tr.curr, tr.pad = nil, 0
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- if sr, ok := tr.r.(io.Seeker); ok {
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- if _, err := sr.Seek(nr, os.SEEK_CUR); err == nil {
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- return
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- }
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|
- }
|
|
|
- _, 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 = ®FileReader{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
|
|
|
-}
|