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@@ -1,377 +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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-// - catch more errors (no first header, etc.)
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-
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-import (
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- "bytes"
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- "errors"
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- "fmt"
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- "io"
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- "os"
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- "path"
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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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- ErrWriteTooLong = errors.New("archive/tar: write too long")
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- ErrFieldTooLong = errors.New("archive/tar: header field too long")
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- ErrWriteAfterClose = errors.New("archive/tar: write after close")
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- errNameTooLong = errors.New("archive/tar: name too long")
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- errInvalidHeader = errors.New("archive/tar: header field too long or contains invalid values")
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-)
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-
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-// A Writer provides sequential writing of a tar archive in POSIX.1 format.
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-// A tar archive consists of a sequence of files.
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-// Call WriteHeader to begin a new file, and then call Write to supply that file's data,
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-// writing at most hdr.Size bytes in total.
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-type Writer struct {
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- w io.Writer
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- err error
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- nb int64 // number of unwritten bytes for current file entry
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- pad int64 // amount of padding to write after current file entry
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- closed bool
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- usedBinary bool // whether the binary numeric field extension was used
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- preferPax bool // use pax header instead of binary numeric header
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-}
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-
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-// NewWriter creates a new Writer writing to w.
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-func NewWriter(w io.Writer) *Writer { return &Writer{w: w} }
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-
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-// Flush finishes writing the current file (optional).
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-func (tw *Writer) Flush() error {
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- if tw.nb > 0 {
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- tw.err = fmt.Errorf("archive/tar: missed writing %d bytes", tw.nb)
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- return tw.err
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- }
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-
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- n := tw.nb + tw.pad
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- for n > 0 && tw.err == nil {
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- nr := n
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- if nr > blockSize {
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- nr = blockSize
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- }
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- var nw int
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- nw, tw.err = tw.w.Write(zeroBlock[0:nr])
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- n -= int64(nw)
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- }
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- tw.nb = 0
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- tw.pad = 0
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- return tw.err
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-}
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-
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-// Write s into b, terminating it with a NUL if there is room.
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-// If the value is too long for the field and allowPax is true add a paxheader record instead
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-func (tw *Writer) cString(b []byte, s string, allowPax bool, paxKeyword string, paxHeaders map[string]string) {
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- needsPaxHeader := allowPax && len(s) > len(b) || !isASCII(s)
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- if needsPaxHeader {
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- paxHeaders[paxKeyword] = s
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- return
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- }
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- if len(s) > len(b) {
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- if tw.err == nil {
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- tw.err = ErrFieldTooLong
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- }
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- return
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- }
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- ascii := toASCII(s)
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- copy(b, ascii)
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- if len(ascii) < len(b) {
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- b[len(ascii)] = 0
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- }
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-}
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-
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-// Encode x as an octal ASCII string and write it into b with leading zeros.
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-func (tw *Writer) octal(b []byte, x int64) {
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- s := strconv.FormatInt(x, 8)
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- // leading zeros, but leave room for a NUL.
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- for len(s)+1 < len(b) {
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- s = "0" + s
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- }
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- tw.cString(b, s, false, paxNone, nil)
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-}
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-
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-// Write x into b, either as octal or as binary (GNUtar/star extension).
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-// If the value is too long for the field and writingPax is enabled both for the field and the add a paxheader record instead
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-func (tw *Writer) numeric(b []byte, x int64, allowPax bool, paxKeyword string, paxHeaders map[string]string) {
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- // Try octal first.
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- s := strconv.FormatInt(x, 8)
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- if len(s) < len(b) {
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- tw.octal(b, x)
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- return
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- }
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-
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- // If it is too long for octal, and pax is preferred, use a pax header
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- if allowPax && tw.preferPax {
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- tw.octal(b, 0)
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- s := strconv.FormatInt(x, 10)
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- paxHeaders[paxKeyword] = s
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- return
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- }
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-
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- // Too big: use binary (big-endian).
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- tw.usedBinary = true
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- for i := len(b) - 1; x > 0 && i >= 0; i-- {
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- b[i] = byte(x)
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- x >>= 8
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- }
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- b[0] |= 0x80 // highest bit indicates binary format
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-}
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-
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-var (
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- minTime = time.Unix(0, 0)
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- // There is room for 11 octal digits (33 bits) of mtime.
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- maxTime = minTime.Add((1<<33 - 1) * time.Second)
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-)
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-
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-// WriteHeader writes hdr and prepares to accept the file's contents.
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-// WriteHeader calls Flush if it is not the first header.
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-// Calling after a Close will return ErrWriteAfterClose.
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-func (tw *Writer) WriteHeader(hdr *Header) error {
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- return tw.writeHeader(hdr, true)
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-}
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-
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-// WriteHeader writes hdr and prepares to accept the file's contents.
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-// WriteHeader calls Flush if it is not the first header.
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-// Calling after a Close will return ErrWriteAfterClose.
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-// As this method is called internally by writePax header to allow it to
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-// suppress writing the pax header.
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-func (tw *Writer) writeHeader(hdr *Header, allowPax bool) error {
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- if tw.closed {
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- return ErrWriteAfterClose
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- }
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- if tw.err == nil {
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- tw.Flush()
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- }
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- if tw.err != nil {
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- return tw.err
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- }
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-
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- // a map to hold pax header records, if any are needed
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- paxHeaders := make(map[string]string)
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-
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- // TODO(shanemhansen): we might want to use PAX headers for
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- // subsecond time resolution, but for now let's just capture
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- // too long fields or non ascii characters
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-
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- header := make([]byte, blockSize)
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- s := slicer(header)
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-
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- // keep a reference to the filename to allow to overwrite it later if we detect that we can use ustar longnames instead of pax
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- pathHeaderBytes := s.next(fileNameSize)
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-
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- tw.cString(pathHeaderBytes, hdr.Name, true, paxPath, paxHeaders)
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-
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- // Handle out of range ModTime carefully.
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- var modTime int64
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- if !hdr.ModTime.Before(minTime) && !hdr.ModTime.After(maxTime) {
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- modTime = hdr.ModTime.Unix()
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- }
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-
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- tw.octal(s.next(8), hdr.Mode) // 100:108
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- tw.numeric(s.next(8), int64(hdr.Uid), true, paxUid, paxHeaders) // 108:116
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- tw.numeric(s.next(8), int64(hdr.Gid), true, paxGid, paxHeaders) // 116:124
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- tw.numeric(s.next(12), hdr.Size, true, paxSize, paxHeaders) // 124:136
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- tw.numeric(s.next(12), modTime, false, paxNone, nil) // 136:148 --- consider using pax for finer granularity
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- s.next(8) // chksum (148:156)
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- s.next(1)[0] = hdr.Typeflag // 156:157
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-
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- tw.cString(s.next(100), hdr.Linkname, true, paxLinkpath, paxHeaders)
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-
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- copy(s.next(8), []byte("ustar\x0000")) // 257:265
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- tw.cString(s.next(32), hdr.Uname, true, paxUname, paxHeaders) // 265:297
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- tw.cString(s.next(32), hdr.Gname, true, paxGname, paxHeaders) // 297:329
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- tw.numeric(s.next(8), hdr.Devmajor, false, paxNone, nil) // 329:337
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- tw.numeric(s.next(8), hdr.Devminor, false, paxNone, nil) // 337:345
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-
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- // keep a reference to the prefix to allow to overwrite it later if we detect that we can use ustar longnames instead of pax
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- prefixHeaderBytes := s.next(155)
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- tw.cString(prefixHeaderBytes, "", false, paxNone, nil) // 345:500 prefix
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-
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- // Use the GNU magic instead of POSIX magic if we used any GNU extensions.
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- if tw.usedBinary {
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- copy(header[257:265], []byte("ustar \x00"))
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- }
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-
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- _, paxPathUsed := paxHeaders[paxPath]
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- // try to use a ustar header when only the name is too long
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- if !tw.preferPax && len(paxHeaders) == 1 && paxPathUsed {
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- suffix := hdr.Name
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- prefix := ""
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- if len(hdr.Name) > fileNameSize && isASCII(hdr.Name) {
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- var err error
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- prefix, suffix, err = tw.splitUSTARLongName(hdr.Name)
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- if err == nil {
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- // ok we can use a ustar long name instead of pax, now correct the fields
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-
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- // remove the path field from the pax header. this will suppress the pax header
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- delete(paxHeaders, paxPath)
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-
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- // update the path fields
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- tw.cString(pathHeaderBytes, suffix, false, paxNone, nil)
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- tw.cString(prefixHeaderBytes, prefix, false, paxNone, nil)
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-
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- // Use the ustar magic if we used ustar long names.
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- if len(prefix) > 0 {
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- copy(header[257:265], []byte("ustar\000"))
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- }
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- }
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- }
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- }
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-
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- // The chksum field is terminated by a NUL and a space.
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- // This is different from the other octal fields.
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- chksum, _ := checksum(header)
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- tw.octal(header[148:155], chksum)
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- header[155] = ' '
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-
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- if tw.err != nil {
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- // problem with header; probably integer too big for a field.
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- return tw.err
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- }
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-
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- if len(paxHeaders) > 0 {
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- if !allowPax {
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- return errInvalidHeader
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- }
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- if err := tw.writePAXHeader(hdr, paxHeaders); err != nil {
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- return err
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- }
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- }
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- tw.nb = int64(hdr.Size)
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- tw.pad = (blockSize - (tw.nb % blockSize)) % blockSize
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-
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- _, tw.err = tw.w.Write(header)
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- return tw.err
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-}
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-
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-// writeUSTARLongName splits a USTAR long name hdr.Name.
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-// name must be < 256 characters. errNameTooLong is returned
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-// if hdr.Name can't be split. The splitting heuristic
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-// is compatible with gnu tar.
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-func (tw *Writer) splitUSTARLongName(name string) (prefix, suffix string, err error) {
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- length := len(name)
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- if length > fileNamePrefixSize+1 {
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- length = fileNamePrefixSize + 1
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- } else if name[length-1] == '/' {
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- length--
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- }
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- i := strings.LastIndex(name[:length], "/")
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- // nlen contains the resulting length in the name field.
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- // plen contains the resulting length in the prefix field.
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- nlen := len(name) - i - 1
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- plen := i
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- if i <= 0 || nlen > fileNameSize || nlen == 0 || plen > fileNamePrefixSize {
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- err = errNameTooLong
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- return
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- }
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- prefix, suffix = name[:i], name[i+1:]
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- return
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-}
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-
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-// writePaxHeader writes an extended pax header to the
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-// archive.
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-func (tw *Writer) writePAXHeader(hdr *Header, paxHeaders map[string]string) error {
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- // Prepare extended header
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- ext := new(Header)
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- ext.Typeflag = TypeXHeader
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- // Setting ModTime is required for reader parsing to
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- // succeed, and seems harmless enough.
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- ext.ModTime = hdr.ModTime
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- // The spec asks that we namespace our pseudo files
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- // with the current pid.
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- pid := os.Getpid()
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- dir, file := path.Split(hdr.Name)
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- fullName := path.Join(dir,
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- fmt.Sprintf("PaxHeaders.%d", pid), file)
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-
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- ascii := toASCII(fullName)
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- if len(ascii) > 100 {
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- ascii = ascii[:100]
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- }
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- ext.Name = ascii
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- // Construct the body
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- var buf bytes.Buffer
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-
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- for k, v := range paxHeaders {
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- fmt.Fprint(&buf, paxHeader(k+"="+v))
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- }
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-
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- ext.Size = int64(len(buf.Bytes()))
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- if err := tw.writeHeader(ext, false); err != nil {
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- return err
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- }
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- if _, err := tw.Write(buf.Bytes()); err != nil {
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- return err
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- }
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- if err := tw.Flush(); err != nil {
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- return err
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- }
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- return nil
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-}
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-
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-// paxHeader formats a single pax record, prefixing it with the appropriate length
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-func paxHeader(msg string) string {
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- const padding = 2 // Extra padding for space and newline
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- size := len(msg) + padding
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- size += len(strconv.Itoa(size))
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- record := fmt.Sprintf("%d %s\n", size, msg)
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- if len(record) != size {
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- // Final adjustment if adding size increased
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- // the number of digits in size
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- size = len(record)
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- record = fmt.Sprintf("%d %s\n", size, msg)
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- }
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- return record
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-}
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-
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-// Write writes to the current entry in the tar archive.
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-// Write returns the error ErrWriteTooLong if more than
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-// hdr.Size bytes are written after WriteHeader.
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-func (tw *Writer) Write(b []byte) (n int, err error) {
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- if tw.closed {
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- err = ErrWriteTooLong
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- return
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- }
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- overwrite := false
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- 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
|
|
|
|
-}
|
|
|