Python termios.tcgetattr() Examples

def launch_proc_with_pty(args, stdin=None, stdout=None, stderr=None, echo=True):
    """Similar to pty.fork, but handle stdin/stdout according to parameters
    instead of connecting to the pty

    :return tuple (subprocess.Popen, pty_master)
    """

    def set_ctty(ctty_fd, master_fd):
        os.setsid()
        os.close(master_fd)
        fcntl.ioctl(ctty_fd, termios.TIOCSCTTY, 0)
        if not echo:
            termios_p = termios.tcgetattr(ctty_fd)
            # termios_p.c_lflags
            termios_p[3] &= ~termios.ECHO
            termios.tcsetattr(ctty_fd, termios.TCSANOW, termios_p)
    (pty_master, pty_slave) = os.openpty()
    # pylint: disable=not-an-iterable
    p = yield from asyncio.create_subprocess_exec(*args,
        stdin=stdin,
        stdout=stdout,
        stderr=stderr,
        preexec_fn=lambda: set_ctty(pty_slave, pty_master))
    os.close(pty_slave)
    return p, open(pty_master, 'wb+', buffering=0) 

def __init__(self):
        # setup
        CozmoTeleop.settings = termios.tcgetattr(sys.stdin)
        atexit.register(self.reset_terminal)

        # vars
        self.head_angle = STD_HEAD_ANGLE
        self.lift_height = STD_LIFT_HEIGHT

        # params
        self.lin_vel = rospy.get_param('~lin_vel', 0.2)
        self.ang_vel = rospy.get_param('~ang_vel', 1.5757)

        # pubs
        self._head_pub = rospy.Publisher('head_angle', Float64, queue_size=1)
        self._lift_pub = rospy.Publisher('lift_height', Float64, queue_size=1)
        self._cmd_vel_pub = rospy.Publisher('cmd_vel', Twist, queue_size=1) 

def raw_terminal():
        if not isatty(sys.stdin):
            f = open("/dev/tty")
            fd = f.fileno()
        else:
            fd = sys.stdin.fileno()
            f = None
        try:
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(fd)
                yield fd
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
                sys.stdout.flush()
                if f is not None:
                    f.close()
        except termios.error:
            pass 

def getecho(self):
        '''This returns the terminal echo mode. This returns True if echo is
        on or False if echo is off. Child applications that are expecting you
        to enter a password often set ECHO False. See waitnoecho().

        Not supported on platforms where ``isatty()`` returns False.  '''

        try:
            attr = termios.tcgetattr(self.fd)
        except termios.error as err:
            errmsg = 'getecho() may not be called on this platform'
            if err.args[0] == errno.EINVAL:
                raise IOError(err.args[0], '%s: %s.' % (err.args[1], errmsg))
            raise

        self.echo = bool(attr[3] & termios.ECHO)
        return self.echo 

def _setecho(fd, state):
    errmsg = 'setecho() may not be called on this platform (it may still be possible to enable/disable echo when spawning the child process)'

    try:
        attr = termios.tcgetattr(fd)
    except termios.error as err:
        if err.args[0] == errno.EINVAL:
            raise IOError(err.args[0], '%s: %s.' % (err.args[1], errmsg))
        raise

    if state:
        attr[3] = attr[3] | termios.ECHO
    else:
        attr[3] = attr[3] & ~termios.ECHO

    try:
        # I tried TCSADRAIN and TCSAFLUSH, but these were inconsistent and
        # blocked on some platforms. TCSADRAIN would probably be ideal.
        termios.tcsetattr(fd, termios.TCSANOW, attr)
    except IOError as err:
        if err.args[0] == errno.EINVAL:
            raise IOError(err.args[0], '%s: %s.' % (err.args[1], errmsg))
        raise 

def __call__(self):
        import sys, tty, termios
        from select import select

        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)

        try:
            tty.setraw(sys.stdin.fileno())

            # [ Wait until ready for reading,
            #   wait until ready for writing
            #   wait for an "exception condition" ]
            # The below line times out after 1 second
            # This can be changed to a floating-point value if necessary
            [i, o, e] = select([sys.stdin.fileno()], [], [], 1)
            if i:
                ch = sys.stdin.read(1)
            else:
                ch = None

        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)

        return ch 

def raw_terminal():
        if not isatty(sys.stdin):
            f = open('/dev/tty')
            fd = f.fileno()
        else:
            fd = sys.stdin.fileno()
            f = None
        try:
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(fd)
                yield fd
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
                sys.stdout.flush()
                if f is not None:
                    f.close()
        except termios.error:
            pass 

def getchar(echo):
        if not isatty(sys.stdin):
            f = open('/dev/tty')
            fd = f.fileno()
        else:
            fd = sys.stdin.fileno()
            f = None
        try:
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(fd)
                ch = os.read(fd, 32)
                if echo and isatty(sys.stdout):
                    sys.stdout.write(ch)
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
                sys.stdout.flush()
                if f is not None:
                    f.close()
        except termios.error:
            pass
        _translate_ch_to_exc(ch)
        return ch.decode(get_best_encoding(sys.stdin), 'replace') 

def getchar(echo):
        if not isatty(sys.stdin):
            f = open('/dev/tty')
            fd = f.fileno()
        else:
            fd = sys.stdin.fileno()
            f = None
        try:
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(fd)
                ch = os.read(fd, 32)
                if echo and isatty(sys.stdout):
                    sys.stdout.write(ch)
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
                sys.stdout.flush()
                if f is not None:
                    f.close()
        except termios.error:
            pass
        _translate_ch_to_exc(ch)
        return ch.decode(get_best_encoding(sys.stdin), 'replace') 

def read_char_no_blocking():
    ''' Read a character in nonblocking mode, if no characters are present in the buffer, return an empty string '''
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    old_flags = fcntl.fcntl(fd, fcntl.F_GETFL)
    try:
        tty.setraw(fd, termios.TCSADRAIN)
        fcntl.fcntl(fd, fcntl.F_SETFL, old_flags | os.O_NONBLOCK)
        return sys.stdin.read(1)
    except IOError as e:
        ErrorNumber = e[0]
        # IOError with ErrorNumber 11(35 in Mac)  is thrown when there is nothing to read(Resource temporarily unavailable)
        if (sys.platform.startswith("linux") and ErrorNumber != 11) or (sys.platform == "darwin" and ErrorNumber != 35):
            raise
        return ""
    finally:
        fcntl.fcntl(fd, fcntl.F_SETFL, old_flags)
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings) 

def restore_echo():
    """Hack for https://stackoverflow.com/questions/6488275 equivalent
    issue with Nmap (from
    http://stackoverflow.com/a/8758047/3223422)

    """
    try:
        fdesc = sys.stdin.fileno()
    except ValueError:
        return
    try:
        attrs = termios.tcgetattr(fdesc)
    except termios.error:
        return
    attrs[3] = attrs[3] | termios.ECHO
    termios.tcsetattr(fdesc, termios.TCSADRAIN, attrs) 

def __init__(self, verbosity, maxJobs):
        super().__init__(verbosity)
        self.__index = 1
        self.__maxJobs = maxJobs
        self.__jobs = {}
        self.__slots = [None] * maxJobs
        self.__tasksDone = 0
        self.__tasksNum = 1

        # disable cursor
        print("\x1b[?25l")

        # disable echo
        try:
            import termios
            fd = sys.stdin.fileno()
            self.__oldTcAttr = termios.tcgetattr(fd)
            new = termios.tcgetattr(fd)
            new[3] = new[3] & ~termios.ECHO
            termios.tcsetattr(fd, termios.TCSADRAIN, new)
        except ImportError:
            pass 

def __init__(self, args, close_stderr=False):
    pid, fd = pty.fork()
    if pid == 0:
      # We're the child. Transfer control to command.
      if close_stderr:
        dev_null = os.open('/dev/null', 0)
        os.dup2(dev_null, 2)
      os.execvp(args[0], args)
    else:
      # Disable echoing.
      attr = termios.tcgetattr(fd)
      attr[3] = attr[3] & ~termios.ECHO
      termios.tcsetattr(fd, termios.TCSANOW, attr)
      # Set up a file()-like interface to the child process
      self.r = os.fdopen(fd, 'r', 1)
      self.w = os.fdopen(os.dup(fd), 'w', 1) 

def _set_vtime(self, vtime):
        if not isinstance(vtime, (float, int)):
            raise TypeError("Invalid vtime type, should be float or integer.")
        elif not (0 <= vtime <= 25.5):
            raise ValueError("Invalid vtime, can be 0 to 25.5 seconds.")

        try:
            iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror)

        cc[termios.VTIME] = int(float(vtime) * 10.0)

        try:
            termios.tcsetattr(self._fd, termios.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror) 

def getchar(echo):
        if not isatty(sys.stdin):
            f = open('/dev/tty')
            fd = f.fileno()
        else:
            fd = sys.stdin.fileno()
            f = None
        try:
            old_settings = termios.tcgetattr(fd)
            try:
                tty.setraw(fd)
                ch = os.read(fd, 32)
                if echo and isatty(sys.stdout):
                    sys.stdout.write(ch)
            finally:
                termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
                sys.stdout.flush()
                if f is not None:
                    f.close()
        except termios.error:
            pass
        _translate_ch_to_exc(ch)
        return ch.decode(get_best_encoding(sys.stdin), 'replace') 

def _set_vmin(self, vmin):
        if not isinstance(vmin, int):
            raise TypeError("Invalid vmin type, should be integer.")
        elif not (0 <= vmin <= 255):
            raise ValueError("Invalid vmin, can be 0 to 255.")

        try:
            iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror)

        cc[termios.VMIN] = vmin

        try:
            termios.tcsetattr(self._fd, termios.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror)

        self._use_termios_timeout = vmin > 0 

def _set_xonxoff(self, enabled):
        if not isinstance(enabled, bool):
            raise TypeError("Invalid enabled type, should be boolean.")

        # Get tty attributes
        try:
            (iflag, oflag, cflag, lflag, ispeed, ospeed, cc) = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        # Modify tty attributes
        iflag &= ~(termios.IXON | termios.IXOFF | termios.IXANY)
        if enabled:
            iflag |= (termios.IXON | termios.IXOFF)

        # Set tty attributes
        try:
            termios.tcsetattr(self._fd, termios.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror) 

def init():
    if os.name == 'posix':
        global old
        old = termios.tcgetattr(fd)
        new = termios.tcgetattr(fd)
        new[3] = new[3] & ~termios.ICANON & ~termios.ECHO
        new[6][termios.VMIN] = 1
        new[6][termios.VTIME] = 0

        # -- Cambiar los atributos
        termios.tcsetattr(fd, termios.TCSANOW, new)

        # -- Restaurar el terminal a la salida
        atexit.register(cleanup_console)
    pass


# -------------------------------------
# Pequena prueba del modulo
# ------------------------------------- 

def _set_stopbits(self, stopbits):
        if not isinstance(stopbits, int):
            raise TypeError("Invalid stop bits type, should be integer.")
        elif stopbits not in [1, 2]:
            raise ValueError("Invalid stop bits, can be 1, 2.")

        # Get tty attributes
        try:
            (iflag, oflag, cflag, lflag, ispeed, ospeed, cc) = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        # Modify tty attributes
        cflag &= ~termios.CSTOPB
        if stopbits == 2:
            cflag |= termios.CSTOPB

        # Set tty attributes
        try:
            termios.tcsetattr(self._fd, termios.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror) 

def _set_baudrate(self, baudrate):
        if not isinstance(baudrate, int):
            raise TypeError("Invalid baud rate type, should be integer.")

        if baudrate not in Serial._BAUDRATE_TO_OSPEED:
            raise ValueError("Unknown baud rate: {:d}".format(baudrate))

        # Get tty attributes
        try:
            (iflag, oflag, cflag, lflag, ispeed, ospeed, cc) = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        # Modify tty attributes
        cflag &= ~(termios.CBAUD | termios.CBAUDEX)
        cflag |= Serial._BAUDRATE_TO_OSPEED[baudrate]
        ispeed = Serial._BAUDRATE_TO_OSPEED[baudrate]
        ospeed = Serial._BAUDRATE_TO_OSPEED[baudrate]

        # Set tty attributes
        try:
            termios.tcsetattr(self._fd, termios.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror) 

def _set_databits(self, databits):
        if not isinstance(databits, int):
            raise TypeError("Invalid data bits type, should be integer.")
        elif databits not in [5, 6, 7, 8]:
            raise ValueError("Invalid data bits, can be 5, 6, 7, 8.")

        # Get tty attributes
        try:
            (iflag, oflag, cflag, lflag, ispeed, ospeed, cc) = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        # Modify tty attributes
        cflag &= ~termios.CSIZE
        cflag |= Serial._DATABITS_TO_CFLAG[databits]

        # Set tty attributes
        try:
            termios.tcsetattr(self._fd, termios.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
        except termios.error as e:
            raise SerialError(e.errno, "Setting serial port attributes: " + e.strerror) 

def pause(secs):
    fd = sys.stdin.fileno()

    oldterm = termios.tcgetattr(fd)
    newattr = termios.tcgetattr(fd)
    newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
    termios.tcsetattr(fd, termios.TCSANOW, newattr)

    oldflags = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, oldflags | os.O_NONBLOCK)

    try:
        ctrlc = False
        paused = False
        t = secs / 0.1
        i = 0
        while i < t:
            if keypressed():
                paused = True
                break
            sleep(0.1)
            i += 1

        if paused:
            while True:
                if keypressed():
                    break
                sleep(0.1)
    except KeyboardInterrupt:
        ctrlc = True

    termios.tcsetattr(fd, termios.TCSAFLUSH, oldterm)
    fcntl.fcntl(fd, fcntl.F_SETFL, oldflags)
    if ctrlc:
        sys.exit(1) 

def _get_stopbits(self):
        # Get tty attributes
        try:
            (_, _, cflag, _, _, _, _) = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        if (cflag & termios.CSTOPB) != 0:
            return 2
        else:
            return 1 

def ask_user(question: str, default: bool, new_line: bool = False) -> bool:
    """
    Asks the user a yes/no question.
    :param question:    The question to ask
    :param default:     The default answer, if user presses enter.
                        True for yes, False for no
    :param new_line:    If new_line before printing the question
    :return:            yes: True, no: False
    """

    yes = ["y"]
    no = ["n"]
    if default:
        yes.append("")
        choices = "Y/n"
    else:
        no.append("")
        choices = "N/y"

    while True:
        print(aurman_question("{} {}: ".format(question, choices), new_line=new_line, to_print=False),
              end='', flush=True)

        # see https://stackoverflow.com/a/36974338
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)

        try:
            tty.setcbreak(fd)
            answer = sys.stdin.read(1)
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)

        print(flush=True)
        user_choice = answer.strip().lower()
        if user_choice in yes or user_choice in no:
            return user_choice in yes
        aurman_error("That was not a valid choice!") 

def __call__(self):
        import sys, tty, termios
        from select import select
        fd = sys.stdin.fileno()
        old_settings = termios.tcgetattr(fd)
        try:
            tty.setraw(sys.stdin.fileno())
            [i, o, e] = select([sys.stdin.fileno()], [], [], 1)
            if i:
                ch = sys.stdin.read(1)
            else:
                ch = None
        finally:
            termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
        return ch 

def _get_rtscts(self):
        # Get tty attributes
        try:
            (_, _, cflag, _, _, _, _) = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        if (cflag & termios.CRTSCTS) != 0:
            return True
        else:
            return False 

def _get_vmin(self):
        try:
            iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        return cc[termios.VMIN] 

def posix_shell(chan):
    import termios
    import tty

    oldtty = termios.tcgetattr(sys.stdin)
    try:
        tty.setraw(sys.stdin.fileno())
        tty.setcbreak(sys.stdin.fileno())
        chan.settimeout(0.0)

        while True:
            r, w, e = select.select([chan, sys.stdin], [], [])
            if chan in r:
                try:
                    x = chan.recv(1024).decode("UTF-8")
                    if len(x) == 0:
                        break
                    sys.stdout.write(x)
                    sys.stdout.flush()
                except socket.timeout:
                    pass

            if sys.stdin in r:
                x = sys.stdin.read(1)
                if len(x) == 0:
                    break
                chan.send(x)
    finally:
        termios.tcsetattr(sys.stdin, termios.TCSADRAIN, oldtty)
        return 

def _get_vtime(self):
        try:
            iflag, oflag, cflag, lflag, ispeed, ospeed, cc = termios.tcgetattr(self._fd)
        except termios.error as e:
            raise SerialError(e.errno, "Getting serial port attributes: " + e.strerror)

        return float(cc[termios.VTIME]) / 10.0 

def getch():
    fd = sys.stdin.fileno()
    old_settings = termios.tcgetattr(fd)
    try:
        tty.setraw(fd)
        ch = sys.stdin.read(1)
    finally:
        termios.tcsetattr(fd, termios.TCSADRAIN, old_settings)
    return ch