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-rw-r--r--src/archive/tar/common.go305
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diff --git a/src/archive/tar/common.go b/src/archive/tar/common.go
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+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package tar implements access to tar archives.
+// It aims to cover most of the variations, including those produced
+// by GNU and BSD tars.
+//
+// References:
+// http://www.freebsd.org/cgi/man.cgi?query=tar&sektion=5
+// http://www.gnu.org/software/tar/manual/html_node/Standard.html
+// http://pubs.opengroup.org/onlinepubs/9699919799/utilities/pax.html
+package tar
+
+import (
+ "bytes"
+ "errors"
+ "fmt"
+ "os"
+ "path"
+ "time"
+)
+
+const (
+ blockSize = 512
+
+ // Types
+ TypeReg = '0' // regular file
+ TypeRegA = '\x00' // regular file
+ TypeLink = '1' // hard link
+ TypeSymlink = '2' // symbolic link
+ TypeChar = '3' // character device node
+ TypeBlock = '4' // block device node
+ TypeDir = '5' // directory
+ TypeFifo = '6' // fifo node
+ TypeCont = '7' // reserved
+ TypeXHeader = 'x' // extended header
+ TypeXGlobalHeader = 'g' // global extended header
+ TypeGNULongName = 'L' // Next file has a long name
+ TypeGNULongLink = 'K' // Next file symlinks to a file w/ a long name
+ TypeGNUSparse = 'S' // sparse file
+)
+
+// A Header represents a single header in a tar archive.
+// Some fields may not be populated.
+type Header struct {
+ Name string // name of header file entry
+ Mode int64 // permission and mode bits
+ Uid int // user id of owner
+ Gid int // group id of owner
+ Size int64 // length in bytes
+ ModTime time.Time // modified time
+ Typeflag byte // type of header entry
+ Linkname string // target name of link
+ Uname string // user name of owner
+ Gname string // group name of owner
+ Devmajor int64 // major number of character or block device
+ Devminor int64 // minor number of character or block device
+ AccessTime time.Time // access time
+ ChangeTime time.Time // status change time
+ Xattrs map[string]string
+}
+
+// File name constants from the tar spec.
+const (
+ fileNameSize = 100 // Maximum number of bytes in a standard tar name.
+ fileNamePrefixSize = 155 // Maximum number of ustar extension bytes.
+)
+
+// FileInfo returns an os.FileInfo for the Header.
+func (h *Header) FileInfo() os.FileInfo {
+ return headerFileInfo{h}
+}
+
+// headerFileInfo implements os.FileInfo.
+type headerFileInfo struct {
+ h *Header
+}
+
+func (fi headerFileInfo) Size() int64 { return fi.h.Size }
+func (fi headerFileInfo) IsDir() bool { return fi.Mode().IsDir() }
+func (fi headerFileInfo) ModTime() time.Time { return fi.h.ModTime }
+func (fi headerFileInfo) Sys() interface{} { return fi.h }
+
+// Name returns the base name of the file.
+func (fi headerFileInfo) Name() string {
+ if fi.IsDir() {
+ return path.Base(path.Clean(fi.h.Name))
+ }
+ return path.Base(fi.h.Name)
+}
+
+// Mode returns the permission and mode bits for the headerFileInfo.
+func (fi headerFileInfo) Mode() (mode os.FileMode) {
+ // Set file permission bits.
+ mode = os.FileMode(fi.h.Mode).Perm()
+
+ // Set setuid, setgid and sticky bits.
+ if fi.h.Mode&c_ISUID != 0 {
+ // setuid
+ mode |= os.ModeSetuid
+ }
+ if fi.h.Mode&c_ISGID != 0 {
+ // setgid
+ mode |= os.ModeSetgid
+ }
+ if fi.h.Mode&c_ISVTX != 0 {
+ // sticky
+ mode |= os.ModeSticky
+ }
+
+ // Set file mode bits.
+ // clear perm, setuid, setgid and sticky bits.
+ m := os.FileMode(fi.h.Mode) &^ 07777
+ if m == c_ISDIR {
+ // directory
+ mode |= os.ModeDir
+ }
+ if m == c_ISFIFO {
+ // named pipe (FIFO)
+ mode |= os.ModeNamedPipe
+ }
+ if m == c_ISLNK {
+ // symbolic link
+ mode |= os.ModeSymlink
+ }
+ if m == c_ISBLK {
+ // device file
+ mode |= os.ModeDevice
+ }
+ if m == c_ISCHR {
+ // Unix character device
+ mode |= os.ModeDevice
+ mode |= os.ModeCharDevice
+ }
+ if m == c_ISSOCK {
+ // Unix domain socket
+ mode |= os.ModeSocket
+ }
+
+ switch fi.h.Typeflag {
+ case TypeLink, TypeSymlink:
+ // hard link, symbolic link
+ mode |= os.ModeSymlink
+ case TypeChar:
+ // character device node
+ mode |= os.ModeDevice
+ mode |= os.ModeCharDevice
+ case TypeBlock:
+ // block device node
+ mode |= os.ModeDevice
+ case TypeDir:
+ // directory
+ mode |= os.ModeDir
+ case TypeFifo:
+ // fifo node
+ mode |= os.ModeNamedPipe
+ }
+
+ return mode
+}
+
+// sysStat, if non-nil, populates h from system-dependent fields of fi.
+var sysStat func(fi os.FileInfo, h *Header) error
+
+// Mode constants from the tar spec.
+const (
+ c_ISUID = 04000 // Set uid
+ c_ISGID = 02000 // Set gid
+ c_ISVTX = 01000 // Save text (sticky bit)
+ c_ISDIR = 040000 // Directory
+ c_ISFIFO = 010000 // FIFO
+ c_ISREG = 0100000 // Regular file
+ c_ISLNK = 0120000 // Symbolic link
+ c_ISBLK = 060000 // Block special file
+ c_ISCHR = 020000 // Character special file
+ c_ISSOCK = 0140000 // Socket
+)
+
+// Keywords for the PAX Extended Header
+const (
+ paxAtime = "atime"
+ paxCharset = "charset"
+ paxComment = "comment"
+ paxCtime = "ctime" // please note that ctime is not a valid pax header.
+ paxGid = "gid"
+ paxGname = "gname"
+ paxLinkpath = "linkpath"
+ paxMtime = "mtime"
+ paxPath = "path"
+ paxSize = "size"
+ paxUid = "uid"
+ paxUname = "uname"
+ paxXattr = "SCHILY.xattr."
+ paxNone = ""
+)
+
+// FileInfoHeader creates a partially-populated Header from fi.
+// If fi describes a symlink, FileInfoHeader records link as the link target.
+// If fi describes a directory, a slash is appended to the name.
+// Because os.FileInfo's Name method returns only the base name of
+// the file it describes, it may be necessary to modify the Name field
+// of the returned header to provide the full path name of the file.
+func FileInfoHeader(fi os.FileInfo, link string) (*Header, error) {
+ if fi == nil {
+ return nil, errors.New("tar: FileInfo is nil")
+ }
+ fm := fi.Mode()
+ h := &Header{
+ Name: fi.Name(),
+ ModTime: fi.ModTime(),
+ Mode: int64(fm.Perm()), // or'd with c_IS* constants later
+ }
+ switch {
+ case fm.IsRegular():
+ h.Mode |= c_ISREG
+ h.Typeflag = TypeReg
+ h.Size = fi.Size()
+ case fi.IsDir():
+ h.Typeflag = TypeDir
+ h.Mode |= c_ISDIR
+ h.Name += "/"
+ case fm&os.ModeSymlink != 0:
+ h.Typeflag = TypeSymlink
+ h.Mode |= c_ISLNK
+ h.Linkname = link
+ case fm&os.ModeDevice != 0:
+ if fm&os.ModeCharDevice != 0 {
+ h.Mode |= c_ISCHR
+ h.Typeflag = TypeChar
+ } else {
+ h.Mode |= c_ISBLK
+ h.Typeflag = TypeBlock
+ }
+ case fm&os.ModeNamedPipe != 0:
+ h.Typeflag = TypeFifo
+ h.Mode |= c_ISFIFO
+ case fm&os.ModeSocket != 0:
+ h.Mode |= c_ISSOCK
+ default:
+ return nil, fmt.Errorf("archive/tar: unknown file mode %v", fm)
+ }
+ if fm&os.ModeSetuid != 0 {
+ h.Mode |= c_ISUID
+ }
+ if fm&os.ModeSetgid != 0 {
+ h.Mode |= c_ISGID
+ }
+ if fm&os.ModeSticky != 0 {
+ h.Mode |= c_ISVTX
+ }
+ if sysStat != nil {
+ return h, sysStat(fi, h)
+ }
+ return h, nil
+}
+
+var zeroBlock = make([]byte, blockSize)
+
+// POSIX specifies a sum of the unsigned byte values, but the Sun tar uses signed byte values.
+// We compute and return both.
+func checksum(header []byte) (unsigned int64, signed int64) {
+ for i := 0; i < len(header); i++ {
+ if i == 148 {
+ // The chksum field (header[148:156]) is special: it should be treated as space bytes.
+ unsigned += ' ' * 8
+ signed += ' ' * 8
+ i += 7
+ continue
+ }
+ unsigned += int64(header[i])
+ signed += int64(int8(header[i]))
+ }
+ return
+}
+
+type slicer []byte
+
+func (sp *slicer) next(n int) (b []byte) {
+ s := *sp
+ b, *sp = s[0:n], s[n:]
+ return
+}
+
+func isASCII(s string) bool {
+ for _, c := range s {
+ if c >= 0x80 {
+ return false
+ }
+ }
+ return true
+}
+
+func toASCII(s string) string {
+ if isASCII(s) {
+ return s
+ }
+ var buf bytes.Buffer
+ for _, c := range s {
+ if c < 0x80 {
+ buf.WriteByte(byte(c))
+ }
+ }
+ return buf.String()
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-17 21:04:50 +0000