|
| 1 | +package extractor |
| 2 | + |
| 3 | +import ( |
| 4 | + "encoding/binary" |
| 5 | + "errors" |
| 6 | + "fmt" |
| 7 | + "os" |
| 8 | + "path/filepath" |
| 9 | + "strings" |
| 10 | + "sync" |
| 11 | +) |
| 12 | + |
| 13 | +type EmbedFile struct { |
| 14 | + Name string `json:"name,omitempty"` |
| 15 | + Data []byte `json:"data,omitempty"` |
| 16 | + Hash []byte `json:"hash,omitempty"` |
| 17 | +} |
| 18 | + |
| 19 | +func Extract(fpath string, vaddr uint64) (ret []EmbedFile, err error) { |
| 20 | + parser, err := NewParser(fpath) |
| 21 | + if err != nil { |
| 22 | + return nil, err |
| 23 | + } |
| 24 | + defer parser.Close() |
| 25 | + |
| 26 | + fr, err := NewFileReader(fpath) |
| 27 | + if err != nil { |
| 28 | + return nil, err |
| 29 | + } |
| 30 | + defer fr.Close() |
| 31 | + |
| 32 | + // parse embed header |
| 33 | + embedHeaderOff, err := parser.ConvRelativeOffset(vaddr) |
| 34 | + if err != nil { |
| 35 | + return nil, err |
| 36 | + } |
| 37 | + header, err := fr.ReadUint64(3, embedHeaderOff) |
| 38 | + if err != nil { |
| 39 | + return nil, err |
| 40 | + } |
| 41 | + if header[1] != header[2] { // length and capacity |
| 42 | + return nil, errors.New("invalid embed header") |
| 43 | + } |
| 44 | + |
| 45 | + filesOff, err := parser.ConvRelativeOffset(header[0]) |
| 46 | + if err != nil { |
| 47 | + return nil, err |
| 48 | + } |
| 49 | + |
| 50 | + // parse embed files |
| 51 | + for i := header[1]; i > 0; i-- { |
| 52 | + // parse file name |
| 53 | + name, err := fr.ReadUint64(2, filesOff) |
| 54 | + if err != nil { |
| 55 | + return nil, err |
| 56 | + } |
| 57 | + offset, err := parser.ConvRelativeOffset(name[0]) |
| 58 | + if err != nil { |
| 59 | + return nil, err |
| 60 | + } |
| 61 | + fname, err := fr.ReadBytes(int(name[1]), offset) |
| 62 | + if err != nil { |
| 63 | + return nil, err |
| 64 | + } |
| 65 | + |
| 66 | + // parse file content |
| 67 | + filesOff += 16 |
| 68 | + var fcontent []byte |
| 69 | + content, err := fr.ReadUint64(2, filesOff) |
| 70 | + if err != nil { |
| 71 | + return nil, err |
| 72 | + } |
| 73 | + if content[0] != 0 { |
| 74 | + offset, err = parser.ConvRelativeOffset(content[0]) |
| 75 | + if err != nil { |
| 76 | + return nil, err |
| 77 | + } |
| 78 | + fcontent, err = fr.ReadBytes(int(content[1]), offset) |
| 79 | + if err != nil { |
| 80 | + return nil, err |
| 81 | + } |
| 82 | + } |
| 83 | + |
| 84 | + // parse file hash |
| 85 | + filesOff += 16 |
| 86 | + hash, err := fr.ReadBytes(16, filesOff) |
| 87 | + if err != nil { |
| 88 | + return nil, err |
| 89 | + } |
| 90 | + |
| 91 | + // create embed file |
| 92 | + ret = append(ret, EmbedFile{Name: string(fname), Data: fcontent, Hash: hash}) |
| 93 | + filesOff += 16 |
| 94 | + } |
| 95 | + |
| 96 | + return ret, nil |
| 97 | +} |
| 98 | + |
| 99 | +type FileReader struct { |
| 100 | + f *os.File |
| 101 | +} |
| 102 | + |
| 103 | +func NewFileReader(fpath string) (*FileReader, error) { |
| 104 | + file, err := os.Open(fpath) |
| 105 | + if err != nil { |
| 106 | + return nil, err |
| 107 | + } |
| 108 | + |
| 109 | + return &FileReader{f: file}, nil |
| 110 | +} |
| 111 | + |
| 112 | +func (fr *FileReader) Close() error { |
| 113 | + if fr.f != nil { |
| 114 | + return fr.f.Close() |
| 115 | + } |
| 116 | + |
| 117 | + return nil |
| 118 | +} |
| 119 | + |
| 120 | +var bufpool = sync.Pool{ |
| 121 | + New: func() interface{} { |
| 122 | + buf := make([]byte, 8) |
| 123 | + return &buf |
| 124 | + }, |
| 125 | +} |
| 126 | + |
| 127 | +func (fr *FileReader) ReadUint64(size int, off uint64) ([]uint64, error) { |
| 128 | + if fr.f == nil { |
| 129 | + return nil, os.ErrClosed |
| 130 | + } |
| 131 | + |
| 132 | + ret := make([]uint64, 0) |
| 133 | + for i := 0; i < size; i++ { |
| 134 | + bufptr := bufpool.Get().(*[]byte) |
| 135 | + buf := *bufptr |
| 136 | + defer bufpool.Put(bufptr) |
| 137 | + |
| 138 | + n, err := fr.f.ReadAt(buf, int64(off)) |
| 139 | + if err != nil { |
| 140 | + return nil, err |
| 141 | + } |
| 142 | + |
| 143 | + if n != 8 { |
| 144 | + return nil, errors.New("read size mismatch") |
| 145 | + } |
| 146 | + |
| 147 | + off += 8 |
| 148 | + ret = append(ret, binary.LittleEndian.Uint64(buf)) |
| 149 | + } |
| 150 | + |
| 151 | + if len(ret) != size { |
| 152 | + return nil, errors.New("read size mismatch") |
| 153 | + } |
| 154 | + |
| 155 | + return ret, nil |
| 156 | +} |
| 157 | + |
| 158 | +func (fr *FileReader) ReadBytes(size int, off uint64) ([]byte, error) { |
| 159 | + if fr.f == nil { |
| 160 | + return nil, os.ErrClosed |
| 161 | + } |
| 162 | + |
| 163 | + ret := make([]byte, size) |
| 164 | + n, err := fr.f.ReadAt(ret, int64(off)) |
| 165 | + if err != nil { |
| 166 | + return nil, err |
| 167 | + } |
| 168 | + |
| 169 | + if n != size { |
| 170 | + return nil, errors.New("read size mismatch") |
| 171 | + } |
| 172 | + |
| 173 | + return ret, nil |
| 174 | +} |
| 175 | + |
| 176 | +func Save(files []EmbedFile, output string) error { |
| 177 | + if err := os.MkdirAll(output, 0755); err != nil { |
| 178 | + return err |
| 179 | + } |
| 180 | + |
| 181 | + for _, ef := range files { |
| 182 | + fullPath := filepath.Join(output, ef.Name) |
| 183 | + |
| 184 | + if strings.HasSuffix(ef.Name, "/") { |
| 185 | + if err := os.MkdirAll(fullPath, 0755); err != nil { |
| 186 | + return err |
| 187 | + } |
| 188 | + } |
| 189 | + |
| 190 | + parentDir := filepath.Dir(fullPath) |
| 191 | + if err := os.MkdirAll(parentDir, 0755); err != nil { |
| 192 | + return err |
| 193 | + } |
| 194 | + |
| 195 | + if ef.Data != nil { |
| 196 | + if err := os.WriteFile(fullPath, ef.Data, 0644); err != nil { |
| 197 | + return fmt.Errorf("failed to write file %s: %v", fullPath, err) |
| 198 | + } |
| 199 | + } |
| 200 | + } |
| 201 | + |
| 202 | + return nil |
| 203 | +} |
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