if err := syscall.Mkfifo(name, 0o600); err != nil {
			t.Fatal(err)
		}
		// The problem only occurs if we use O_NONBLOCK here.
		rd, err := os.OpenFile(name, os.O_RDONLY|syscall.O_NONBLOCK, 0o600)
		if err != nil {
			t.Fatal(err)
		}
		wr, err := os.OpenFile(name, os.O_WRONLY|syscall.O_NONBLOCK, 0o600)
		if err != nil {
			t.Fatal(err)
		}
		const msg = "message"

	}
	ofile, ok := file.(*openFile)
	if !ok {
		return nil, &fs.PathError{Op: "read", Path: name, Err: errors.New("is a directory")}
	}
	return []byte(ofile.f.data), nil
}

// An openFile is a regular file open for reading.
type openFile struct {
	f      *file // the file itself
	offset int64 // current read offset
}

var (
	_ io.Seeker   = (*openFile)(nil)
	_ io.ReaderAt = (*openFile)(nil)

	Trace("Open", path)
	return openFile(path, os.O_RDONLY, 0)
}

func openFile(path string, flag int, perm os.FileMode) (*os.File, error) {
	cpath := canonicalize(path)
	if node, ok := overlay[cpath]; ok {
		// Opening a file in the overlay.
		if node.isDir() {
			return nil, &fs.PathError{Op: "OpenFile", Path: path, Err: errors.New("fsys.OpenFile doesn't support opening directories yet")}
		}

	}
	defer inf.Close()

	fi, err := inf.Stat()
	if err != nil {
		fatal("accessing input meta-data file %s: %v", inpath, err)
	}

	outf, err := os.OpenFile(outpath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, fi.Mode())
	if err != nil {
		fatal("opening output meta-data file %s: %v", outpath, err)
	}

	_, err = io.Copy(outf, inf)
	outf.Close()
	if err != nil {

	if len(newID) != len(id) {
		log.Fatalf("%s: build ID length mismatch %q vs %q", file, id, newID)
	}

	if len(matches) == 0 {
		return
	}

	f, err = os.OpenFile(file, os.O_RDWR, 0)
	if err != nil {
		log.Fatal(err)
	}
	if err := buildid.Rewrite(f, matches, newID); err != nil {
		log.Fatal(err)
	}
	if err := f.Close(); err != nil {
		log.Fatal(err)
	}

type newFileKind int

const (
	// kindNewFile means that the descriptor was passed to us via NewFile.
	kindNewFile newFileKind = iota
	// kindOpenFile means that the descriptor was opened using
	// Open, Create, or OpenFile.
	kindOpenFile
	// kindPipe means that the descriptor was opened using Pipe.
	kindPipe
	// kindSock means that the descriptor is a network file descriptor

func (s *DependenciesStub) writeAllToDryRunPath() error {
	path := DryRunFilePath.Get()
	if path != "" {
		// Print the input into the given output file.
		f, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY, 0o644)
		if err != nil {
			return fmt.Errorf("unable to open dry run output file %v: %v", path, err)
		}

		defer f.Close()

		for _, line := range s.ExecutedAll {

	in, err := os.Open(srcFilepath)
	if err != nil {
		return err
	}
	defer in.Close()

	perm, err := in.Stat()
	if err != nil {
		return err
	}

	out, err := os.OpenFile(filepath.Join(targetDir, targetFilename), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm.Mode())
	if err != nil {
		return err
	}
	defer out.Close()

	if _, err := io.Copy(out, in); err != nil {
		return err
	}

		t.Fatalf("Child 1 and 2 are not in the same process group")
	}
}

func TestForeground(t *testing.T) {
	signal.Ignore(syscall.SIGTTIN, syscall.SIGTTOU)
	defer signal.Reset()

	tty, err := os.OpenFile("/dev/tty", os.O_RDWR, 0)
	if err != nil {
		t.Skipf("Can't test Foreground. Couldn't open /dev/tty: %s", err)
	}
	defer tty.Close()

	ttyFD := int(tty.Fd())

	fpgrp, err := syscall.Tcgetpgrp(ttyFD)

		for i, fi := range fis {
			des[i] = fs.FileInfoToDirEntry(fi)
		}
		return des, nil
	}
	return os.ReadDir(path)
}

// openFile calls ctxt.OpenFile (if not nil) or else os.Open.
func (ctxt *Context) openFile(path string) (io.ReadCloser, error) {
	if fn := ctxt.OpenFile; fn != nil {
		return fn(path)
	}

	f, err := os.Open(path)
	if err != nil {
		return nil, err // nil interface
	}