// extract extracts the original sound from the input video.
func extract(in string) error {
// Probe to determine the audio codec.
cmd := exec.Command("ffprobe", "-show_streams", "-select_streams", "a", in)
buf, err := cmd.Output()
if err != nil {
return fmt.Errorf("audio codec probe failed; %v", err)
}
re := regexp.MustCompile("codec_name=(.*)")
matches := re.FindSubmatch(buf)
if len(matches) < 2 {
return fmt.Errorf("unable to locate codec_name")
}
codec := string(matches[1])
// Copy the original sound from the input video.
stderr := new(bytes.Buffer)
out := fmt.Sprintf("%s.%s", pathutil.TrimExt(in), codec)
cmd = exec.Command("ffmpeg", "-i", in, "-vn", "-y", "-acodec", "copy", out)
cmd.Stderr = stderr
err = cmd.Run()
if err != nil {
log.Println(stderr.String())
return err
}
fmt.Printf("Created %q.\n", out)
return nil
}
// dump stores the graph as a DOT file and an image representation of the graph
// as a PNG file with filenames based on "-o" flag.
func dump(graph *dot.Graph) error {
// Store graph to DOT file.
dotPath := flagOut
if !flagQuiet {
log.Printf("Creating: %q\n", dotPath)
}
err := ioutil.WriteFile(dotPath, []byte(graph.String()), 0644)
if err != nil {
return errutil.Err(err)
}
// Generate an image representation of the graph.
if flagImage {
pngPath := pathutil.TrimExt(dotPath) + ".png"
if !flagQuiet {
log.Printf("Creating: %q\n", pngPath)
}
cmd := exec.Command("dot", "-Tpng", "-o", pngPath, dotPath)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err = cmd.Run()
if err != nil {
return errutil.Err(err)
}
}
return nil
}
// flac2wav converts the provided FLAC file to a WAV file.
func flac2wav(path string) error {
// Open FLAC file.
stream, err := flac.Open(path)
if err != nil {
return err
}
defer stream.Close()
// Create WAV file.
wavPath := pathutil.TrimExt(path) + ".wav"
if !flagForce {
exists, err := osutil.Exists(wavPath)
if err != nil {
return err
}
if exists {
return fmt.Errorf("the file %q exists already", wavPath)
}
}
fw, err := os.Create(wavPath)
if err != nil {
return err
}
defer fw.Close()
// Create WAV encoder.
conf := audio.Config{
Channels: int(stream.Info.NChannels),
SampleRate: int(stream.Info.SampleRate),
}
enc, err := wav.NewEncoder(fw, conf)
if err != nil {
return err
}
defer enc.Close()
for {
// Decode FLAC audio samples.
frame, err := stream.ParseNext()
if err != nil {
if err == io.EOF {
break
}
return err
}
// Encode WAV audio samples.
samples := make(audio.Int16, 1)
for i := 0; i < int(frame.BlockSize); i++ {
for _, subframe := range frame.Subframes {
samples[0] = int16(subframe.Samples[i])
_, err = enc.Write(samples)
if err != nil {
return err
}
}
}
}
return nil
}
// ll2go parses the provided LLVM IR assembly file and decompiles it to Go
// source code.
func ll2go(llPath string) error {
// File name and file path without extension.
baseName := pathutil.FileName(llPath)
basePath := pathutil.TrimExt(llPath)
// TODO: Create graphs in /tmp/xxx_graphs/*.dot
// Create temporary foo.dot file, e.g.
//
// foo.ll -> foo_graphs/*.dot
dotDir := basePath + "_graphs"
if ok, _ := osutil.Exists(dotDir); !ok {
if !flagQuiet {
log.Printf("Creating control flow graphs for %q.\n", filepath.Base(llPath))
}
cmd := exec.Command("ll2dot", "-q", "-funcs", flagFuncs, "-f", llPath)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
return errutil.Err(err)
}
}
// Create temporary foo.bc file, e.g.
//
// foo.ll -> foo.bc
bcPath := fmt.Sprintf("/tmp/%s.bc", baseName)
cmd := exec.Command("llvm-as", "-o", bcPath, llPath)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
return errutil.Err(err)
}
// Remove temporary foo.bc file.
defer func() {
err = os.Remove(bcPath)
if err != nil {
log.Fatalln(errutil.Err(err))
}
}()
// Parse foo.bc
module, err := llvm.ParseBitcodeFile(bcPath)
if err != nil {
return errutil.Err(err)
}
defer module.Dispose()
// Get function names.
var funcNames []string
if len(flagFuncs) > 0 {
// Get function names from command line flag:
//
// -funcs="foo,bar"
funcNames = strings.Split(flagFuncs, ",")
} else {
// Get all function names.
for llFunc := module.FirstFunction(); !llFunc.IsNil(); llFunc = llvm.NextFunction(llFunc) {
if llFunc.IsDeclaration() {
// Ignore function declarations (e.g. functions without bodies).
continue
}
funcNames = append(funcNames, llFunc.Name())
}
}
// Locate package name.
pkgName := flagPkgName
if len(flagPkgName) == 0 {
pkgName = baseName
for _, funcName := range funcNames {
if funcName == "main" {
pkgName = "main"
break
}
}
}
// Create foo.go.
file := &ast.File{
Name: newIdent(pkgName),
}
// TODO: Implement support for global variables.
// Parse each function.
for _, funcName := range funcNames {
if !flagQuiet {
log.Printf("Parsing function: %q\n", funcName)
}
graph, err := parseCFG(basePath, funcName)
if err != nil {
return errutil.Err(err)
}
// Structure the CFG.
dotDir := basePath + "_graphs"
dotName := funcName + ".dot"
dotPath := path.Join(dotDir, dotName)
jsonName := funcName + ".json"
jsonPath := path.Join(dotDir, jsonName)
if ok, _ := osutil.Exists(jsonPath); !ok {
cmd := exec.Command("restructure", "-o", jsonPath, dotPath)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
if !flagQuiet {
log.Printf("Structuring function: %q\n", funcName)
}
err = cmd.Run()
if err != nil {
return errutil.Err(err)
}
}
var hprims []*xprimitive.Primitive
fr, err := os.Open(jsonPath)
if err != nil {
return errutil.Err(err)
}
defer fr.Close()
dec := json.NewDecoder(fr)
err = dec.Decode(&hprims)
if err != nil {
return errutil.Err(err)
}
f, err := parseFunc(graph, module, funcName, hprims)
if err != nil {
return errutil.Err(err)
}
file.Decls = append(file.Decls, f)
if flagVerbose && !flagQuiet {
printFunc(f)
}
}
// Store Go source code to file.
goPath := basePath + ".go"
if !flagQuiet {
log.Printf("Creating: %q\n", goPath)
}
return storeFile(goPath, file)
}
// ll2dot parses the provided LLVM IR assembly file and generates a control flow
// graph for each of its defined functions using one node per basic block.
func ll2dot(llPath string) error {
// File name and file path without extension.
baseName := pathutil.FileName(llPath)
basePath := pathutil.TrimExt(llPath)
// Create temporary foo.bc file, e.g.
//
// foo.ll -> foo.bc
bcPath := fmt.Sprintf("/tmp/%s.bc", baseName)
cmd := exec.Command("llvm-as", "-o", bcPath, llPath)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
return errutil.Err(err)
}
// Remove temporary foo.bc file.
defer func() {
err = os.Remove(bcPath)
if err != nil {
log.Fatalln(errutil.Err(err))
}
}()
// Create output directory for the control flow graphs.
dotDir := basePath + "_graphs"
if flagForce {
// Force remove existing graph directory.
err = os.RemoveAll(dotDir)
if err != nil {
return errutil.Err(err)
}
}
err = os.Mkdir(dotDir, 0755)
if err != nil {
return errutil.Err(err)
}
// Parse foo.bc
module, err := llvm.ParseBitcodeFile(bcPath)
if err != nil {
return errutil.Err(err)
}
defer module.Dispose()
// Get function names.
var funcNames []string
if len(flagFuncs) > 0 {
// Get function names from command line flag:
//
// -funcs="foo,bar"
funcNames = strings.Split(flagFuncs, ",")
} else {
// Get all function names.
for f := module.FirstFunction(); !f.IsNil(); f = llvm.NextFunction(f) {
if f.IsDeclaration() {
// Ignore function declarations (e.g. functions without bodies).
continue
}
funcNames = append(funcNames, f.Name())
}
}
// Generate a control flow graph for each function.
for _, funcName := range funcNames {
// Generate control flow graph.
if !flagQuiet {
log.Printf("Parsing function: %q\n", funcName)
}
graph, err := createCFG(module, funcName)
if err != nil {
return errutil.Err(err)
}
// Store the control flow graph.
//
// For a source file "foo.ll" containing the functions "bar" and "baz" the
// following DOT files will be created:
//
// foo_graphs/bar.dot
// foo_graphs/baz.dot
dotName := funcName + ".dot"
dotPath := filepath.Join(dotDir, dotName)
if !flagQuiet {
log.Printf("Creating: %q\n", dotPath)
}
buf := []byte(graph.String())
err = ioutil.WriteFile(dotPath, buf, 0644)
if err != nil {
return errutil.Err(err)
}
// Generate an image representation of the control flow graph.
if flagImage {
pngName := funcName + ".png"
pngPath := filepath.Join(dotDir, pngName)
if !flagQuiet {
log.Printf("Creating: %q\n", pngPath)
}
cmd := exec.Command("dot", "-Tpng", "-o", pngPath, dotPath)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err = cmd.Run()
if err != nil {
return errutil.Err(err)
}
}
}
return nil
}
// flac2wav converts the provided FLAC file to a WAV file.
func flac2wav(path string) error {
// Open FLAC file.
fr, err := os.Open(path)
if err != nil {
return err
}
defer fr.Close()
// Create FLAC decoder.
dec, magic, err := audio.NewDecoder(fr)
if err != nil {
return err
}
fmt.Println("magic:", magic)
conf := dec.Config()
fmt.Println("conf:", conf)
// Create WAV file.
wavPath := pathutil.TrimExt(path) + ".wav"
if !flagForce {
exists, err := osutil.Exists(wavPath)
if err != nil {
return err
}
if exists {
return fmt.Errorf("the file %q exists already", wavPath)
}
}
fw, err := os.Create(wavPath)
if err != nil {
return err
}
defer fw.Close()
// Create WAV encoder.
enc, err := wav.NewEncoder(fw, conf)
if err != nil {
return err
}
defer enc.Close()
// Encode WAV audio samples copied from the FLAC decoder.
// TODO(u): Replace with audio.Copy as soon as that doesn't cause audio
// sample conversions.
buf := make(audio.PCM16Samples, (32*1024)/8)
for {
nr, er := dec.Read(buf)
if nr > 0 {
nw, ew := enc.Write(buf[0:nr])
if ew != nil {
return ew
}
if nr != nw {
return audio.ErrShortWrite
}
}
if er == audio.EOS {
return nil
}
if er != nil {
return er
}
}
}