// Compute output ID.
	h := sha256.New()
	if _, err := file.Seek(0, 0); err != nil {
		return OutputID{}, 0, err
	}
	size, err := io.Copy(h, file)
	if err != nil {
		return OutputID{}, 0, err
	}
	var out OutputID
	h.Sum(out[:0])

	if _, err := file.Seek(0, 0); err != nil {
		return OutputID{}, 0, err
	}

	if !c.can[cmdPut] {

func Getdirentries(fd int, buf []byte, basep *uintptr) (n int, err error) {
	n, err = Getdents(fd, buf)
	if err != nil || basep == nil {
		return
	}

	var off int64
	off, err = Seek(fd, 0, 1 /* SEEK_CUR */)
	if err != nil {
		*basep = ^uintptr(0)
		return
	}
	*basep = uintptr(off)
	if unsafe.Sizeof(*basep) == 8 {
		return
	}
	if off>>32 != 0 {

		}

		go func() {
			defer close(errc)
			defer conn.Close()

			f, err := os.Open(newton)
			if err != nil {
				errc <- err
				return
			}
			defer f.Close()
			if _, err := f.Seek(seekTo, io.SeekStart); err != nil {
				errc <- err
				return
			}

			expectSendfile(t, conn, func() {
				_, err = io.CopyN(conn, f, sendSize)
			})
			if err != nil {
				errc <- err

	f.offset += int64(n)
	return n, nil
}

func (f *openFile) Seek(offset int64, whence int) (int64, error) {
	switch whence {
	case 0:
		// offset += 0
	case 1:
		offset += f.offset
	case 2:
		offset += int64(len(f.f.data))
	}
	if offset < 0 || offset > int64(len(f.f.data)) {
		return 0, &fs.PathError{Op: "seek", Path: f.f.name, Err: fs.ErrInvalid}
	}
	f.offset = offset
	return offset, nil

//sys	pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK

func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {
	var ts *Timespec
	if timeout != nil {

//sys	pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
//sys	Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error)

//sys	pwrite(fd int, p []byte, offset int64) (n int, err error) = SYS_PWRITE64
//sys	Renameat(olddirfd int, oldpath string, newdirfd int, newpath string) (err error)
//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK
//sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)
//sys	Setfsgid(gid int) (err error)
//sys	Setfsuid(uid int) (err error)

type xcoffBiobuf bio.Reader

func (f *xcoffBiobuf) ReadAt(p []byte, off int64) (int, error) {
	ret := ((*bio.Reader)(f)).MustSeek(off, 0)
	if ret < 0 {
		return 0, errors.New("fail to seek")
	}
	n, err := f.Read(p)
	if err != nil {
		return 0, err
	}
	return n, nil
}

// loads the Xcoff file pn from f.
// Symbols are written into loader, and a slice of the text symbols is returned.

	ENOTTY          Errno = 25      /* Not a typewriter */
	EFBIG           Errno = 27      /* File too large */
	ENOSPC          Errno = 28      /* No space left on device */
	ESPIPE          Errno = 29      /* Illegal seek */
	EROFS           Errno = 30      /* Read-only file system */
	EMLINK          Errno = 31      /* Too many links */
	EPIPE           Errno = 32      /* Broken pipe */
	ENAMETOOLONG    Errno = 36      /* File name too long */

		var err error
		off, err = b.emitFunc(w, off, f)
		if err != nil {
			return digest, err
		}
	}

	// Back-patch the length.
	totalLength := uint32(off)
	if _, err := w.Seek(0, io.SeekStart); err != nil {
		return digest, err
	}
	b.wrUint32(w, totalLength)
	if b.werr != nil {
		return digest, b.werr
	}
	return digest, nil
}