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// Copyright 2010 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 zip provides support for reading and writing ZIP archives.
See: https://www.pkware.com/documents/casestudies/APPNOTE.TXT
This package does not support disk spanning.
A note about ZIP64:
To be backwards compatible the FileHeader has both 32 and 64 bit Size
fields. The 64 bit fields will always contain the correct value and
for normal archives both fields will be the same. For files requiring
the ZIP64 format the 32 bit fields will be 0xffffffff and the 64 bit
fields must be used instead.
*/
package zip
import (
"os"
"path"
"time"
)
// Compression methods.
const (
Store uint16 = 0
Deflate uint16 = 8
)
const (
fileHeaderSignature = 0x04034b50
directoryHeaderSignature = 0x02014b50
directoryEndSignature = 0x06054b50
directory64LocSignature = 0x07064b50
directory64EndSignature = 0x06064b50
dataDescriptorSignature = 0x08074b50 // de-facto standard; required by OS X Finder
fileHeaderLen = 30 // + filename + extra
directoryHeaderLen = 46 // + filename + extra + comment
directoryEndLen = 22 // + comment
dataDescriptorLen = 16 // four uint32: descriptor signature, crc32, compressed size, size
dataDescriptor64Len = 24 // descriptor with 8 byte sizes
directory64LocLen = 20 //
directory64EndLen = 56 // + extra
// Constants for the first byte in CreatorVersion
creatorFAT = 0
creatorUnix = 3
creatorNTFS = 11
creatorVFAT = 14
creatorMacOSX = 19
// version numbers
zipVersion20 = 20 // 2.0
zipVersion45 = 45 // 4.5 (reads and writes zip64 archives)
// limits for non zip64 files
uint16max = (1 << 16) - 1
uint32max = (1 << 32) - 1
// extra header id's
zip64ExtraId = 0x0001 // zip64 Extended Information Extra Field
)
// FileHeader describes a file within a zip file.
// See the zip spec for details.
type FileHeader struct {
// Name is the name of the file.
// It must be a relative path: it must not start with a drive
// letter (e.g. C:) or leading slash, and only forward slashes
// are allowed.
Name string
CreatorVersion uint16
ReaderVersion uint16
Flags uint16
Method uint16
ModifiedTime uint16 // MS-DOS time
ModifiedDate uint16 // MS-DOS date
CRC32 uint32
CompressedSize uint32 // Deprecated: Use CompressedSize64 instead.
UncompressedSize uint32 // Deprecated: Use UncompressedSize64 instead.
CompressedSize64 uint64
UncompressedSize64 uint64
Extra []byte
ExternalAttrs uint32 // Meaning depends on CreatorVersion
Comment string
}
// FileInfo returns an os.FileInfo for the FileHeader.
func (h *FileHeader) FileInfo() os.FileInfo {
return headerFileInfo{h}
}
// headerFileInfo implements os.FileInfo.
type headerFileInfo struct {
fh *FileHeader
}
func (fi headerFileInfo) Name() string { return path.Base(fi.fh.Name) }
func (fi headerFileInfo) Size() int64 {
if fi.fh.UncompressedSize64 > 0 {
return int64(fi.fh.UncompressedSize64)
}
return int64(fi.fh.UncompressedSize)
}
func (fi headerFileInfo) IsDir() bool { return fi.Mode().IsDir() }
func (fi headerFileInfo) ModTime() time.Time { return fi.fh.ModTime() }
func (fi headerFileInfo) Mode() os.FileMode { return fi.fh.Mode() }
func (fi headerFileInfo) Sys() interface{} { return fi.fh }
// FileInfoHeader creates a partially-populated FileHeader from an
// os.FileInfo.
// 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) (*FileHeader, error) {
size := fi.Size()
fh := &FileHeader{
Name: fi.Name(),
UncompressedSize64: uint64(size),
}
fh.SetModTime(fi.ModTime())
fh.SetMode(fi.Mode())
if fh.UncompressedSize64 > uint32max {
fh.UncompressedSize = uint32max
} else {
fh.UncompressedSize = uint32(fh.UncompressedSize64)
}
return fh, nil
}
type directoryEnd struct {
diskNbr uint32 // unused
dirDiskNbr uint32 // unused
dirRecordsThisDisk uint64 // unused
directoryRecords uint64
directorySize uint64
directoryOffset uint64 // relative to file
commentLen uint16
comment string
}
// msDosTimeToTime converts an MS-DOS date and time into a time.Time.
// The resolution is 2s.
// See: http://msdn.microsoft.com/en-us/library/ms724247(v=VS.85).aspx
func msDosTimeToTime(dosDate, dosTime uint16) time.Time {
return time.Date(
// date bits 0-4: day of month; 5-8: month; 9-15: years since 1980
int(dosDate>>9+1980),
time.Month(dosDate>>5&0xf),
int(dosDate&0x1f),
// time bits 0-4: second/2; 5-10: minute; 11-15: hour
int(dosTime>>11),
int(dosTime>>5&0x3f),
int(dosTime&0x1f*2),
0, // nanoseconds
time.UTC,
)
}
// timeToMsDosTime converts a time.Time to an MS-DOS date and time.
// The resolution is 2s.
// See: http://msdn.microsoft.com/en-us/library/ms724274(v=VS.85).aspx
func timeToMsDosTime(t time.Time) (fDate uint16, fTime uint16) {
t = t.In(time.UTC)
fDate = uint16(t.Day() + int(t.Month())<<5 + (t.Year()-1980)<<9)
fTime = uint16(t.Second()/2 + t.Minute()<<5 + t.Hour()<<11)
return
}
// ModTime returns the modification time in UTC.
// The resolution is 2s.
func (h *FileHeader) ModTime() time.Time {
return msDosTimeToTime(h.ModifiedDate, h.ModifiedTime)
}
// SetModTime sets the ModifiedTime and ModifiedDate fields to the given time in UTC.
// The resolution is 2s.
func (h *FileHeader) SetModTime(t time.Time) {
h.ModifiedDate, h.ModifiedTime = timeToMsDosTime(t)
}
const (
// Unix constants. The specification doesn't mention them,
// but these seem to be the values agreed on by tools.
s_IFMT = 0xf000
s_IFSOCK = 0xc000
s_IFLNK = 0xa000
s_IFREG = 0x8000
s_IFBLK = 0x6000
s_IFDIR = 0x4000
s_IFCHR = 0x2000
s_IFIFO = 0x1000
s_ISUID = 0x800
s_ISGID = 0x400
s_ISVTX = 0x200
msdosDir = 0x10
msdosReadOnly = 0x01
)
// Mode returns the permission and mode bits for the FileHeader.
func (h *FileHeader) Mode() (mode os.FileMode) {
switch h.CreatorVersion >> 8 {
case creatorUnix, creatorMacOSX:
mode = unixModeToFileMode(h.ExternalAttrs >> 16)
case creatorNTFS, creatorVFAT, creatorFAT:
mode = msdosModeToFileMode(h.ExternalAttrs)
}
if len(h.Name) > 0 && h.Name[len(h.Name)-1] == '/' {
mode |= os.ModeDir
}
return mode
}
// SetMode changes the permission and mode bits for the FileHeader.
func (h *FileHeader) SetMode(mode os.FileMode) {
h.CreatorVersion = h.CreatorVersion&0xff | creatorUnix<<8
h.ExternalAttrs = fileModeToUnixMode(mode) << 16
// set MSDOS attributes too, as the original zip does.
if mode&os.ModeDir != 0 {
h.ExternalAttrs |= msdosDir
}
if mode&0200 == 0 {
h.ExternalAttrs |= msdosReadOnly
}
}
// isZip64 reports whether the file size exceeds the 32 bit limit
func (fh *FileHeader) isZip64() bool {
return fh.CompressedSize64 >= uint32max || fh.UncompressedSize64 >= uint32max
}
func msdosModeToFileMode(m uint32) (mode os.FileMode) {
if m&msdosDir != 0 {
mode = os.ModeDir | 0777
} else {
mode = 0666
}
if m&msdosReadOnly != 0 {
mode &^= 0222
}
return mode
}
func fileModeToUnixMode(mode os.FileMode) uint32 {
var m uint32
switch mode & os.ModeType {
default:
m = s_IFREG
case os.ModeDir:
m = s_IFDIR
case os.ModeSymlink:
m = s_IFLNK
case os.ModeNamedPipe:
m = s_IFIFO
case os.ModeSocket:
m = s_IFSOCK
case os.ModeDevice:
if mode&os.ModeCharDevice != 0 {
m = s_IFCHR
} else {
m = s_IFBLK
}
}
if mode&os.ModeSetuid != 0 {
m |= s_ISUID
}
if mode&os.ModeSetgid != 0 {
m |= s_ISGID
}
if mode&os.ModeSticky != 0 {
m |= s_ISVTX
}
return m | uint32(mode&0777)
}
func unixModeToFileMode(m uint32) os.FileMode {
mode := os.FileMode(m & 0777)
switch m & s_IFMT {
case s_IFBLK:
mode |= os.ModeDevice
case s_IFCHR:
mode |= os.ModeDevice | os.ModeCharDevice
case s_IFDIR:
mode |= os.ModeDir
case s_IFIFO:
mode |= os.ModeNamedPipe
case s_IFLNK:
mode |= os.ModeSymlink
case s_IFREG:
// nothing to do
case s_IFSOCK:
mode |= os.ModeSocket
}
if m&s_ISGID != 0 {
mode |= os.ModeSetgid
}
if m&s_ISUID != 0 {
mode |= os.ModeSetuid
}
if m&s_ISVTX != 0 {
mode |= os.ModeSticky
}
return mode
}