1 // Copyright 2016 Google Inc. All rights reserved. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package zip 16 17 import ( 18 "errors" 19 "io" 20 ) 21 22 const DataDescriptorFlag = 0x8 23 const ExtendedTimeStampTag = 0x5455 24 25 func (w *Writer) CopyFrom(orig *File, newName string) error { 26 if w.last != nil && !w.last.closed { 27 if err := w.last.close(); err != nil { 28 return err 29 } 30 w.last = nil 31 } 32 33 fileHeader := orig.FileHeader 34 fileHeader.Name = newName 35 fh := &fileHeader 36 37 // In some cases, we need strip the extras if it change between Central Directory 38 // and Local File Header. 39 fh.Extra = stripExtras(fh.Extra) 40 41 h := &header{ 42 FileHeader: fh, 43 offset: uint64(w.cw.count), 44 } 45 w.dir = append(w.dir, h) 46 47 if err := writeHeader(w.cw, fh); err != nil { 48 return err 49 } 50 dataOffset, err := orig.DataOffset() 51 if err != nil { 52 return err 53 } 54 io.Copy(w.cw, io.NewSectionReader(orig.zipr, dataOffset, int64(orig.CompressedSize64))) 55 56 if orig.hasDataDescriptor() { 57 // Write data descriptor. 58 var buf []byte 59 if fh.isZip64() { 60 buf = make([]byte, dataDescriptor64Len) 61 } else { 62 buf = make([]byte, dataDescriptorLen) 63 } 64 b := writeBuf(buf) 65 b.uint32(dataDescriptorSignature) 66 b.uint32(fh.CRC32) 67 if fh.isZip64() { 68 b.uint64(fh.CompressedSize64) 69 b.uint64(fh.UncompressedSize64) 70 } else { 71 b.uint32(fh.CompressedSize) 72 b.uint32(fh.UncompressedSize) 73 } 74 _, err = w.cw.Write(buf) 75 } 76 return err 77 } 78 79 // The zip64 extras change between the Central Directory and Local File Header, while we use 80 // the same structure for both. The Local File Haeder is taken care of by us writing a data 81 // descriptor with the zip64 values. The Central Directory Entry is written by Close(), where 82 // the zip64 extra is automatically created and appended when necessary. 83 // 84 // The extended-timestamp extra block changes between the Central Directory Header and Local 85 // File Header. 86 // Extended-Timestamp extra(LFH): <tag-size-flag-modtime-actime-changetime> 87 // Extended-Timestamp extra(CDH): <tag-size-flag-modtime> 88 func stripExtras(input []byte) []byte { 89 ret := []byte{} 90 91 for len(input) >= 4 { 92 r := readBuf(input) 93 tag := r.uint16() 94 size := r.uint16() 95 if int(size) > len(r) { 96 break 97 } 98 if tag != zip64ExtraId && tag != ExtendedTimeStampTag { 99 ret = append(ret, input[:4+size]...) 100 } 101 input = input[4+size:] 102 } 103 104 // Keep any trailing data 105 ret = append(ret, input...) 106 107 return ret 108 } 109 110 // CreateCompressedHeader adds a file to the zip file using the provied 111 // FileHeader for the file metadata. 112 // It returns a Writer to which the already compressed file contents 113 // should be written. 114 // 115 // The UncompressedSize64 and CRC32 entries in the FileHeader must be filled 116 // out already. 117 // 118 // The file's contents must be written to the io.Writer before the next 119 // call to Create, CreateHeader, CreateCompressedHeader, or Close. The 120 // provided FileHeader fh must not be modified after a call to 121 // CreateCompressedHeader 122 func (w *Writer) CreateCompressedHeader(fh *FileHeader) (io.WriteCloser, error) { 123 if w.last != nil && !w.last.closed { 124 if err := w.last.close(); err != nil { 125 return nil, err 126 } 127 } 128 if len(w.dir) > 0 && w.dir[len(w.dir)-1].FileHeader == fh { 129 // See https://golang.org/issue/11144 confusion. 130 return nil, errors.New("archive/zip: invalid duplicate FileHeader") 131 } 132 133 fh.Flags |= DataDescriptorFlag // we will write a data descriptor 134 135 fh.CreatorVersion = fh.CreatorVersion&0xff00 | zipVersion20 // preserve compatibility byte 136 fh.ReaderVersion = zipVersion20 137 138 fw := &compressedFileWriter{ 139 fileWriter{ 140 zipw: w.cw, 141 compCount: &countWriter{w: w.cw}, 142 }, 143 } 144 145 h := &header{ 146 FileHeader: fh, 147 offset: uint64(w.cw.count), 148 } 149 w.dir = append(w.dir, h) 150 fw.header = h 151 152 if err := writeHeader(w.cw, fh); err != nil { 153 return nil, err 154 } 155 156 w.last = &fw.fileWriter 157 return fw, nil 158 } 159 160 // Updated version of CreateHeader that doesn't enforce writing a data descriptor 161 func (w *Writer) CreateHeaderAndroid(fh *FileHeader) (io.Writer, error) { 162 writeDataDescriptor := fh.Method != Store 163 if writeDataDescriptor { 164 fh.Flags &= DataDescriptorFlag 165 } else { 166 fh.Flags &= ^uint16(DataDescriptorFlag) 167 } 168 return w.createHeaderImpl(fh) 169 } 170 171 type compressedFileWriter struct { 172 fileWriter 173 } 174 175 func (w *compressedFileWriter) Write(p []byte) (int, error) { 176 if w.closed { 177 return 0, errors.New("zip: write to closed file") 178 } 179 return w.compCount.Write(p) 180 } 181 182 func (w *compressedFileWriter) Close() error { 183 if w.closed { 184 return errors.New("zip: file closed twice") 185 } 186 w.closed = true 187 188 // update FileHeader 189 fh := w.header.FileHeader 190 fh.CompressedSize64 = uint64(w.compCount.count) 191 192 if fh.isZip64() { 193 fh.CompressedSize = uint32max 194 fh.UncompressedSize = uint32max 195 fh.ReaderVersion = zipVersion45 // requires 4.5 - File uses ZIP64 format extensions 196 } else { 197 fh.CompressedSize = uint32(fh.CompressedSize64) 198 fh.UncompressedSize = uint32(fh.UncompressedSize64) 199 } 200 201 // Write data descriptor. This is more complicated than one would 202 // think, see e.g. comments in zipfile.c:putextended() and 203 // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7073588. 204 // The approach here is to write 8 byte sizes if needed without 205 // adding a zip64 extra in the local header (too late anyway). 206 var buf []byte 207 if fh.isZip64() { 208 buf = make([]byte, dataDescriptor64Len) 209 } else { 210 buf = make([]byte, dataDescriptorLen) 211 } 212 b := writeBuf(buf) 213 b.uint32(dataDescriptorSignature) // de-facto standard, required by OS X 214 b.uint32(fh.CRC32) 215 if fh.isZip64() { 216 b.uint64(fh.CompressedSize64) 217 b.uint64(fh.UncompressedSize64) 218 } else { 219 b.uint32(fh.CompressedSize) 220 b.uint32(fh.UncompressedSize) 221 } 222 _, err := w.zipw.Write(buf) 223 return err 224 } 225
