| #!/usr/bin/env python |
| # |
| # backend for serial IO for POSIX compatible systems, like Linux, OSX |
| # |
| # This file is part of pySerial. https://github.com/pyserial/pyserial |
| # (C) 2001-2020 Chris Liechti <[email protected]> |
| # |
| # SPDX-License-Identifier: BSD-3-Clause |
| # |
| # parts based on code from Grant B. Edwards <[email protected]>: |
| # ftp://ftp.visi.com/users/grante/python/PosixSerial.py |
| # |
| # references: http://www.easysw.com/~mike/serial/serial.html |
| |
| # Collection of port names (was previously used by number_to_device which was |
| # removed. |
| # - Linux /dev/ttyS%d (confirmed) |
| # - cygwin/win32 /dev/com%d (confirmed) |
| # - openbsd (OpenBSD) /dev/cua%02d |
| # - bsd*, freebsd* /dev/cuad%d |
| # - darwin (OS X) /dev/cuad%d |
| # - netbsd /dev/dty%02d (NetBSD 1.6 testing by Erk) |
| # - irix (IRIX) /dev/ttyf%d (partially tested) names depending on flow control |
| # - hp (HP-UX) /dev/tty%dp0 (not tested) |
| # - sunos (Solaris/SunOS) /dev/tty%c (letters, 'a'..'z') (confirmed) |
| # - aix (AIX) /dev/tty%d |
| |
| |
| from __future__ import absolute_import |
| |
| # pylint: disable=abstract-method |
| import errno |
| import fcntl |
| import os |
| import select |
| import struct |
| import sys |
| import termios |
| |
| import serial |
| from serial.serialutil import SerialBase, SerialException, to_bytes, \ |
| PortNotOpenError, SerialTimeoutException, Timeout |
| |
| |
| class PlatformSpecificBase(object): |
| BAUDRATE_CONSTANTS = {} |
| |
| def _set_special_baudrate(self, baudrate): |
| raise NotImplementedError('non-standard baudrates are not supported on this platform') |
| |
| def _set_rs485_mode(self, rs485_settings): |
| raise NotImplementedError('RS485 not supported on this platform') |
| |
| def set_low_latency_mode(self, low_latency_settings): |
| raise NotImplementedError('Low latency not supported on this platform') |
| |
| def _update_break_state(self): |
| """\ |
| Set break: Controls TXD. When active, no transmitting is possible. |
| """ |
| if self._break_state: |
| fcntl.ioctl(self.fd, TIOCSBRK) |
| else: |
| fcntl.ioctl(self.fd, TIOCCBRK) |
| |
| |
| # some systems support an extra flag to enable the two in POSIX unsupported |
| # paritiy settings for MARK and SPACE |
| CMSPAR = 0 # default, for unsupported platforms, override below |
| |
| # try to detect the OS so that a device can be selected... |
| # this code block should supply a device() and set_special_baudrate() function |
| # for the platform |
| plat = sys.platform.lower() |
| |
| if plat[:5] == 'linux': # Linux (confirmed) # noqa |
| import array |
| |
| # extra termios flags |
| CMSPAR = 0o10000000000 # Use "stick" (mark/space) parity |
| |
| # baudrate ioctls |
| TCGETS2 = 0x802C542A |
| TCSETS2 = 0x402C542B |
| BOTHER = 0o010000 |
| |
| # RS485 ioctls |
| TIOCGRS485 = 0x542E |
| TIOCSRS485 = 0x542F |
| SER_RS485_ENABLED = 0b00000001 |
| SER_RS485_RTS_ON_SEND = 0b00000010 |
| SER_RS485_RTS_AFTER_SEND = 0b00000100 |
| SER_RS485_RX_DURING_TX = 0b00010000 |
| |
| class PlatformSpecific(PlatformSpecificBase): |
| BAUDRATE_CONSTANTS = { |
| 0: 0o000000, # hang up |
| 50: 0o000001, |
| 75: 0o000002, |
| 110: 0o000003, |
| 134: 0o000004, |
| 150: 0o000005, |
| 200: 0o000006, |
| 300: 0o000007, |
| 600: 0o000010, |
| 1200: 0o000011, |
| 1800: 0o000012, |
| 2400: 0o000013, |
| 4800: 0o000014, |
| 9600: 0o000015, |
| 19200: 0o000016, |
| 38400: 0o000017, |
| 57600: 0o010001, |
| 115200: 0o010002, |
| 230400: 0o010003, |
| 460800: 0o010004, |
| 500000: 0o010005, |
| 576000: 0o010006, |
| 921600: 0o010007, |
| 1000000: 0o010010, |
| 1152000: 0o010011, |
| 1500000: 0o010012, |
| 2000000: 0o010013, |
| 2500000: 0o010014, |
| 3000000: 0o010015, |
| 3500000: 0o010016, |
| 4000000: 0o010017 |
| } |
| |
| def set_low_latency_mode(self, low_latency_settings): |
| buf = array.array('i', [0] * 32) |
| |
| try: |
| # get serial_struct |
| fcntl.ioctl(self.fd, termios.TIOCGSERIAL, buf) |
| |
| # set or unset ASYNC_LOW_LATENCY flag |
| if low_latency_settings: |
| buf[4] |= 0x2000 |
| else: |
| buf[4] &= ~0x2000 |
| |
| # set serial_struct |
| fcntl.ioctl(self.fd, termios.TIOCSSERIAL, buf) |
| except IOError as e: |
| raise ValueError('Failed to update ASYNC_LOW_LATENCY flag to {}: {}'.format(low_latency_settings, e)) |
| |
| def _set_special_baudrate(self, baudrate): |
| # right size is 44 on x86_64, allow for some growth |
| buf = array.array('i', [0] * 64) |
| try: |
| # get serial_struct |
| fcntl.ioctl(self.fd, TCGETS2, buf) |
| # set custom speed |
| buf[2] &= ~termios.CBAUD |
| buf[2] |= BOTHER |
| buf[9] = buf[10] = baudrate |
| |
| # set serial_struct |
| fcntl.ioctl(self.fd, TCSETS2, buf) |
| except IOError as e: |
| raise ValueError('Failed to set custom baud rate ({}): {}'.format(baudrate, e)) |
| |
| def _set_rs485_mode(self, rs485_settings): |
| buf = array.array('i', [0] * 8) # flags, delaytx, delayrx, padding |
| try: |
| fcntl.ioctl(self.fd, TIOCGRS485, buf) |
| buf[0] |= SER_RS485_ENABLED |
| if rs485_settings is not None: |
| if rs485_settings.loopback: |
| buf[0] |= SER_RS485_RX_DURING_TX |
| else: |
| buf[0] &= ~SER_RS485_RX_DURING_TX |
| if rs485_settings.rts_level_for_tx: |
| buf[0] |= SER_RS485_RTS_ON_SEND |
| else: |
| buf[0] &= ~SER_RS485_RTS_ON_SEND |
| if rs485_settings.rts_level_for_rx: |
| buf[0] |= SER_RS485_RTS_AFTER_SEND |
| else: |
| buf[0] &= ~SER_RS485_RTS_AFTER_SEND |
| if rs485_settings.delay_before_tx is not None: |
| buf[1] = int(rs485_settings.delay_before_tx * 1000) |
| if rs485_settings.delay_before_rx is not None: |
| buf[2] = int(rs485_settings.delay_before_rx * 1000) |
| else: |
| buf[0] = 0 # clear SER_RS485_ENABLED |
| fcntl.ioctl(self.fd, TIOCSRS485, buf) |
| except IOError as e: |
| raise ValueError('Failed to set RS485 mode: {}'.format(e)) |
| |
| |
| elif plat == 'cygwin': # cygwin/win32 (confirmed) |
| |
| class PlatformSpecific(PlatformSpecificBase): |
| BAUDRATE_CONSTANTS = { |
| 128000: 0x01003, |
| 256000: 0x01005, |
| 500000: 0x01007, |
| 576000: 0x01008, |
| 921600: 0x01009, |
| 1000000: 0x0100a, |
| 1152000: 0x0100b, |
| 1500000: 0x0100c, |
| 2000000: 0x0100d, |
| 2500000: 0x0100e, |
| 3000000: 0x0100f |
| } |
| |
| |
| elif plat[:6] == 'darwin': # OS X |
| import array |
| IOSSIOSPEED = 0x80045402 # _IOW('T', 2, speed_t) |
| |
| class PlatformSpecific(PlatformSpecificBase): |
| osx_version = os.uname()[2].split('.') |
| TIOCSBRK = 0x2000747B # _IO('t', 123) |
| TIOCCBRK = 0x2000747A # _IO('t', 122) |
| |
| # Tiger or above can support arbitrary serial speeds |
| if int(osx_version[0]) >= 8: |
| def _set_special_baudrate(self, baudrate): |
| # use IOKit-specific call to set up high speeds |
| buf = array.array('i', [baudrate]) |
| fcntl.ioctl(self.fd, IOSSIOSPEED, buf, 1) |
| |
| def _update_break_state(self): |
| """\ |
| Set break: Controls TXD. When active, no transmitting is possible. |
| """ |
| if self._break_state: |
| fcntl.ioctl(self.fd, PlatformSpecific.TIOCSBRK) |
| else: |
| fcntl.ioctl(self.fd, PlatformSpecific.TIOCCBRK) |
| |
| elif plat[:3] == 'bsd' or \ |
| plat[:7] == 'freebsd' or \ |
| plat[:6] == 'netbsd' or \ |
| plat[:7] == 'openbsd': |
| |
| class ReturnBaudrate(object): |
| def __getitem__(self, key): |
| return key |
| |
| class PlatformSpecific(PlatformSpecificBase): |
| # Only tested on FreeBSD: |
| # The baud rate may be passed in as |
| # a literal value. |
| BAUDRATE_CONSTANTS = ReturnBaudrate() |
| |
| TIOCSBRK = 0x2000747B # _IO('t', 123) |
| TIOCCBRK = 0x2000747A # _IO('t', 122) |
| |
| |
| def _update_break_state(self): |
| """\ |
| Set break: Controls TXD. When active, no transmitting is possible. |
| """ |
| if self._break_state: |
| fcntl.ioctl(self.fd, PlatformSpecific.TIOCSBRK) |
| else: |
| fcntl.ioctl(self.fd, PlatformSpecific.TIOCCBRK) |
| |
| else: |
| class PlatformSpecific(PlatformSpecificBase): |
| pass |
| |
| |
| # load some constants for later use. |
| # try to use values from termios, use defaults from linux otherwise |
| TIOCMGET = getattr(termios, 'TIOCMGET', 0x5415) |
| TIOCMBIS = getattr(termios, 'TIOCMBIS', 0x5416) |
| TIOCMBIC = getattr(termios, 'TIOCMBIC', 0x5417) |
| TIOCMSET = getattr(termios, 'TIOCMSET', 0x5418) |
| |
| # TIOCM_LE = getattr(termios, 'TIOCM_LE', 0x001) |
| TIOCM_DTR = getattr(termios, 'TIOCM_DTR', 0x002) |
| TIOCM_RTS = getattr(termios, 'TIOCM_RTS', 0x004) |
| # TIOCM_ST = getattr(termios, 'TIOCM_ST', 0x008) |
| # TIOCM_SR = getattr(termios, 'TIOCM_SR', 0x010) |
| |
| TIOCM_CTS = getattr(termios, 'TIOCM_CTS', 0x020) |
| TIOCM_CAR = getattr(termios, 'TIOCM_CAR', 0x040) |
| TIOCM_RNG = getattr(termios, 'TIOCM_RNG', 0x080) |
| TIOCM_DSR = getattr(termios, 'TIOCM_DSR', 0x100) |
| TIOCM_CD = getattr(termios, 'TIOCM_CD', TIOCM_CAR) |
| TIOCM_RI = getattr(termios, 'TIOCM_RI', TIOCM_RNG) |
| # TIOCM_OUT1 = getattr(termios, 'TIOCM_OUT1', 0x2000) |
| # TIOCM_OUT2 = getattr(termios, 'TIOCM_OUT2', 0x4000) |
| if hasattr(termios, 'TIOCINQ'): |
| TIOCINQ = termios.TIOCINQ |
| else: |
| TIOCINQ = getattr(termios, 'FIONREAD', 0x541B) |
| TIOCOUTQ = getattr(termios, 'TIOCOUTQ', 0x5411) |
| |
| TIOCM_zero_str = struct.pack('I', 0) |
| TIOCM_RTS_str = struct.pack('I', TIOCM_RTS) |
| TIOCM_DTR_str = struct.pack('I', TIOCM_DTR) |
| |
| TIOCSBRK = getattr(termios, 'TIOCSBRK', 0x5427) |
| TIOCCBRK = getattr(termios, 'TIOCCBRK', 0x5428) |
| |
| |
| class Serial(SerialBase, PlatformSpecific): |
| """\ |
| Serial port class POSIX implementation. Serial port configuration is |
| done with termios and fcntl. Runs on Linux and many other Un*x like |
| systems. |
| """ |
| |
| def open(self): |
| """\ |
| Open port with current settings. This may throw a SerialException |
| if the port cannot be opened.""" |
| if self._port is None: |
| raise SerialException("Port must be configured before it can be used.") |
| if self.is_open: |
| raise SerialException("Port is already open.") |
| self.fd = None |
| # open |
| try: |
| self.fd = os.open(self.portstr, os.O_RDWR | os.O_NOCTTY | os.O_NONBLOCK) |
| except OSError as msg: |
| self.fd = None |
| raise SerialException(msg.errno, "could not open port {}: {}".format(self._port, msg)) |
| #~ fcntl.fcntl(self.fd, fcntl.F_SETFL, 0) # set blocking |
| |
| self.pipe_abort_read_r, self.pipe_abort_read_w = None, None |
| self.pipe_abort_write_r, self.pipe_abort_write_w = None, None |
| |
| try: |
| self._reconfigure_port(force_update=True) |
| |
| try: |
| if not self._dsrdtr: |
| self._update_dtr_state() |
| if not self._rtscts: |
| self._update_rts_state() |
| except IOError as e: |
| # ignore Invalid argument and Inappropriate ioctl |
| if e.errno not in (errno.EINVAL, errno.ENOTTY): |
| raise |
| |
| self._reset_input_buffer() |
| |
| self.pipe_abort_read_r, self.pipe_abort_read_w = os.pipe() |
| self.pipe_abort_write_r, self.pipe_abort_write_w = os.pipe() |
| fcntl.fcntl(self.pipe_abort_read_r, fcntl.F_SETFL, os.O_NONBLOCK) |
| fcntl.fcntl(self.pipe_abort_write_r, fcntl.F_SETFL, os.O_NONBLOCK) |
| except BaseException: |
| try: |
| os.close(self.fd) |
| except Exception: |
| # ignore any exception when closing the port |
| # also to keep original exception that happened when setting up |
| pass |
| self.fd = None |
| |
| if self.pipe_abort_read_w is not None: |
| os.close(self.pipe_abort_read_w) |
| self.pipe_abort_read_w = None |
| if self.pipe_abort_read_r is not None: |
| os.close(self.pipe_abort_read_r) |
| self.pipe_abort_read_r = None |
| if self.pipe_abort_write_w is not None: |
| os.close(self.pipe_abort_write_w) |
| self.pipe_abort_write_w = None |
| if self.pipe_abort_write_r is not None: |
| os.close(self.pipe_abort_write_r) |
| self.pipe_abort_write_r = None |
| |
| raise |
| |
| self.is_open = True |
| |
| def _reconfigure_port(self, force_update=False): |
| """Set communication parameters on opened port.""" |
| if self.fd is None: |
| raise SerialException("Can only operate on a valid file descriptor") |
| |
| # if exclusive lock is requested, create it before we modify anything else |
| if self._exclusive is not None: |
| if self._exclusive: |
| try: |
| fcntl.flock(self.fd, fcntl.LOCK_EX | fcntl.LOCK_NB) |
| except IOError as msg: |
| raise SerialException(msg.errno, "Could not exclusively lock port {}: {}".format(self._port, msg)) |
| else: |
| fcntl.flock(self.fd, fcntl.LOCK_UN) |
| |
| custom_baud = None |
| |
| vmin = vtime = 0 # timeout is done via select |
| if self._inter_byte_timeout is not None: |
| vmin = 1 |
| vtime = int(self._inter_byte_timeout * 10) |
| try: |
| orig_attr = termios.tcgetattr(self.fd) |
| iflag, oflag, cflag, lflag, ispeed, ospeed, cc = orig_attr |
| except termios.error as msg: # if a port is nonexistent but has a /dev file, it'll fail here |
| raise SerialException("Could not configure port: {}".format(msg)) |
| # set up raw mode / no echo / binary |
| cflag |= (termios.CLOCAL | termios.CREAD) |
| lflag &= ~(termios.ICANON | termios.ECHO | termios.ECHOE | |
| termios.ECHOK | termios.ECHONL | |
| termios.ISIG | termios.IEXTEN) # |termios.ECHOPRT |
| for flag in ('ECHOCTL', 'ECHOKE'): # netbsd workaround for Erk |
| if hasattr(termios, flag): |
| lflag &= ~getattr(termios, flag) |
| |
| oflag &= ~(termios.OPOST | termios.ONLCR | termios.OCRNL) |
| iflag &= ~(termios.INLCR | termios.IGNCR | termios.ICRNL | termios.IGNBRK) |
| if hasattr(termios, 'IUCLC'): |
| iflag &= ~termios.IUCLC |
| if hasattr(termios, 'PARMRK'): |
| iflag &= ~termios.PARMRK |
| |
| # setup baud rate |
| try: |
| ispeed = ospeed = getattr(termios, 'B{}'.format(self._baudrate)) |
| except AttributeError: |
| try: |
| ispeed = ospeed = self.BAUDRATE_CONSTANTS[self._baudrate] |
| except KeyError: |
| #~ raise ValueError('Invalid baud rate: %r' % self._baudrate) |
| |
| # See if BOTHER is defined for this platform; if it is, use |
| # this for a speed not defined in the baudrate constants list. |
| try: |
| ispeed = ospeed = BOTHER |
| except NameError: |
| # may need custom baud rate, it isn't in our list. |
| ispeed = ospeed = getattr(termios, 'B38400') |
| |
| try: |
| custom_baud = int(self._baudrate) # store for later |
| except ValueError: |
| raise ValueError('Invalid baud rate: {!r}'.format(self._baudrate)) |
| else: |
| if custom_baud < 0: |
| raise ValueError('Invalid baud rate: {!r}'.format(self._baudrate)) |
| |
| # setup char len |
| cflag &= ~termios.CSIZE |
| if self._bytesize == 8: |
| cflag |= termios.CS8 |
| elif self._bytesize == 7: |
| cflag |= termios.CS7 |
| elif self._bytesize == 6: |
| cflag |= termios.CS6 |
| elif self._bytesize == 5: |
| cflag |= termios.CS5 |
| else: |
| raise ValueError('Invalid char len: {!r}'.format(self._bytesize)) |
| # setup stop bits |
| if self._stopbits == serial.STOPBITS_ONE: |
| cflag &= ~(termios.CSTOPB) |
| elif self._stopbits == serial.STOPBITS_ONE_POINT_FIVE: |
| cflag |= (termios.CSTOPB) # XXX same as TWO.. there is no POSIX support for 1.5 |
| elif self._stopbits == serial.STOPBITS_TWO: |
| cflag |= (termios.CSTOPB) |
| else: |
| raise ValueError('Invalid stop bit specification: {!r}'.format(self._stopbits)) |
| # setup parity |
| iflag &= ~(termios.INPCK | termios.ISTRIP) |
| if self._parity == serial.PARITY_NONE: |
| cflag &= ~(termios.PARENB | termios.PARODD | CMSPAR) |
| elif self._parity == serial.PARITY_EVEN: |
| cflag &= ~(termios.PARODD | CMSPAR) |
| cflag |= (termios.PARENB) |
| elif self._parity == serial.PARITY_ODD: |
| cflag &= ~CMSPAR |
| cflag |= (termios.PARENB | termios.PARODD) |
| elif self._parity == serial.PARITY_MARK and CMSPAR: |
| cflag |= (termios.PARENB | CMSPAR | termios.PARODD) |
| elif self._parity == serial.PARITY_SPACE and CMSPAR: |
| cflag |= (termios.PARENB | CMSPAR) |
| cflag &= ~(termios.PARODD) |
| else: |
| raise ValueError('Invalid parity: {!r}'.format(self._parity)) |
| # setup flow control |
| # xonxoff |
| if hasattr(termios, 'IXANY'): |
| if self._xonxoff: |
| iflag |= (termios.IXON | termios.IXOFF) # |termios.IXANY) |
| else: |
| iflag &= ~(termios.IXON | termios.IXOFF | termios.IXANY) |
| else: |
| if self._xonxoff: |
| iflag |= (termios.IXON | termios.IXOFF) |
| else: |
| iflag &= ~(termios.IXON | termios.IXOFF) |
| # rtscts |
| if hasattr(termios, 'CRTSCTS'): |
| if self._rtscts: |
| cflag |= (termios.CRTSCTS) |
| else: |
| cflag &= ~(termios.CRTSCTS) |
| elif hasattr(termios, 'CNEW_RTSCTS'): # try it with alternate constant name |
| if self._rtscts: |
| cflag |= (termios.CNEW_RTSCTS) |
| else: |
| cflag &= ~(termios.CNEW_RTSCTS) |
| # XXX should there be a warning if setting up rtscts (and xonxoff etc) fails?? |
| |
| # buffer |
| # vmin "minimal number of characters to be read. 0 for non blocking" |
| if vmin < 0 or vmin > 255: |
| raise ValueError('Invalid vmin: {!r}'.format(vmin)) |
| cc[termios.VMIN] = vmin |
| # vtime |
| if vtime < 0 or vtime > 255: |
| raise ValueError('Invalid vtime: {!r}'.format(vtime)) |
| cc[termios.VTIME] = vtime |
| # activate settings |
| if force_update or [iflag, oflag, cflag, lflag, ispeed, ospeed, cc] != orig_attr: |
| termios.tcsetattr( |
| self.fd, |
| termios.TCSANOW, |
| [iflag, oflag, cflag, lflag, ispeed, ospeed, cc]) |
| |
| # apply custom baud rate, if any |
| if custom_baud is not None: |
| self._set_special_baudrate(custom_baud) |
| |
| if self._rs485_mode is not None: |
| self._set_rs485_mode(self._rs485_mode) |
| |
| def close(self): |
| """Close port""" |
| if self.is_open: |
| if self.fd is not None: |
| os.close(self.fd) |
| self.fd = None |
| os.close(self.pipe_abort_read_w) |
| os.close(self.pipe_abort_read_r) |
| os.close(self.pipe_abort_write_w) |
| os.close(self.pipe_abort_write_r) |
| self.pipe_abort_read_r, self.pipe_abort_read_w = None, None |
| self.pipe_abort_write_r, self.pipe_abort_write_w = None, None |
| self.is_open = False |
| |
| # - - - - - - - - - - - - - - - - - - - - - - - - |
| |
| @property |
| def in_waiting(self): |
| """Return the number of bytes currently in the input buffer.""" |
| #~ s = fcntl.ioctl(self.fd, termios.FIONREAD, TIOCM_zero_str) |
| s = fcntl.ioctl(self.fd, TIOCINQ, TIOCM_zero_str) |
| return struct.unpack('I', s)[0] |
| |
| # select based implementation, proved to work on many systems |
| def read(self, size=1): |
| """\ |
| Read size bytes from the serial port. If a timeout is set it may |
| return less characters as requested. With no timeout it will block |
| until the requested number of bytes is read. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| read = bytearray() |
| timeout = Timeout(self._timeout) |
| while len(read) < size: |
| try: |
| ready, _, _ = select.select([self.fd, self.pipe_abort_read_r], [], [], timeout.time_left()) |
| if self.pipe_abort_read_r in ready: |
| os.read(self.pipe_abort_read_r, 1000) |
| break |
| # If select was used with a timeout, and the timeout occurs, it |
| # returns with empty lists -> thus abort read operation. |
| # For timeout == 0 (non-blocking operation) also abort when |
| # there is nothing to read. |
| if not ready: |
| break # timeout |
| buf = os.read(self.fd, size - len(read)) |
| except OSError as e: |
| # this is for Python 3.x where select.error is a subclass of |
| # OSError ignore BlockingIOErrors and EINTR. other errors are shown |
| # https://www.python.org/dev/peps/pep-0475. |
| if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('read failed: {}'.format(e)) |
| except select.error as e: |
| # this is for Python 2.x |
| # ignore BlockingIOErrors and EINTR. all errors are shown |
| # see also http://www.python.org/dev/peps/pep-3151/#select |
| if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('read failed: {}'.format(e)) |
| else: |
| # read should always return some data as select reported it was |
| # ready to read when we get to this point. |
| if not buf: |
| # Disconnected devices, at least on Linux, show the |
| # behavior that they are always ready to read immediately |
| # but reading returns nothing. |
| raise SerialException( |
| 'device reports readiness to read but returned no data ' |
| '(device disconnected or multiple access on port?)') |
| read.extend(buf) |
| |
| if timeout.expired(): |
| break |
| return bytes(read) |
| |
| def cancel_read(self): |
| if self.is_open: |
| os.write(self.pipe_abort_read_w, b"x") |
| |
| def cancel_write(self): |
| if self.is_open: |
| os.write(self.pipe_abort_write_w, b"x") |
| |
| def write(self, data): |
| """Output the given byte string over the serial port.""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| d = to_bytes(data) |
| tx_len = length = len(d) |
| timeout = Timeout(self._write_timeout) |
| while tx_len > 0: |
| try: |
| n = os.write(self.fd, d) |
| if timeout.is_non_blocking: |
| # Zero timeout indicates non-blocking - simply return the |
| # number of bytes of data actually written |
| return n |
| elif not timeout.is_infinite: |
| # when timeout is set, use select to wait for being ready |
| # with the time left as timeout |
| if timeout.expired(): |
| raise SerialTimeoutException('Write timeout') |
| abort, ready, _ = select.select([self.pipe_abort_write_r], [self.fd], [], timeout.time_left()) |
| if abort: |
| os.read(self.pipe_abort_write_r, 1000) |
| break |
| if not ready: |
| raise SerialTimeoutException('Write timeout') |
| else: |
| assert timeout.time_left() is None |
| # wait for write operation |
| abort, ready, _ = select.select([self.pipe_abort_write_r], [self.fd], [], None) |
| if abort: |
| os.read(self.pipe_abort_write_r, 1) |
| break |
| if not ready: |
| raise SerialException('write failed (select)') |
| d = d[n:] |
| tx_len -= n |
| except SerialException: |
| raise |
| except OSError as e: |
| # this is for Python 3.x where select.error is a subclass of |
| # OSError ignore BlockingIOErrors and EINTR. other errors are shown |
| # https://www.python.org/dev/peps/pep-0475. |
| if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('write failed: {}'.format(e)) |
| except select.error as e: |
| # this is for Python 2.x |
| # ignore BlockingIOErrors and EINTR. all errors are shown |
| # see also http://www.python.org/dev/peps/pep-3151/#select |
| if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('write failed: {}'.format(e)) |
| if not timeout.is_non_blocking and timeout.expired(): |
| raise SerialTimeoutException('Write timeout') |
| return length - len(d) |
| |
| def flush(self): |
| """\ |
| Flush of file like objects. In this case, wait until all data |
| is written. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| termios.tcdrain(self.fd) |
| |
| def _reset_input_buffer(self): |
| """Clear input buffer, discarding all that is in the buffer.""" |
| termios.tcflush(self.fd, termios.TCIFLUSH) |
| |
| def reset_input_buffer(self): |
| """Clear input buffer, discarding all that is in the buffer.""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| self._reset_input_buffer() |
| |
| def reset_output_buffer(self): |
| """\ |
| Clear output buffer, aborting the current output and discarding all |
| that is in the buffer. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| termios.tcflush(self.fd, termios.TCOFLUSH) |
| |
| def send_break(self, duration=0.25): |
| """\ |
| Send break condition. Timed, returns to idle state after given |
| duration. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| termios.tcsendbreak(self.fd, int(duration / 0.25)) |
| |
| def _update_rts_state(self): |
| """Set terminal status line: Request To Send""" |
| if self._rts_state: |
| fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_RTS_str) |
| else: |
| fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_RTS_str) |
| |
| def _update_dtr_state(self): |
| """Set terminal status line: Data Terminal Ready""" |
| if self._dtr_state: |
| fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str) |
| else: |
| fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str) |
| |
| @property |
| def cts(self): |
| """Read terminal status line: Clear To Send""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) |
| return struct.unpack('I', s)[0] & TIOCM_CTS != 0 |
| |
| @property |
| def dsr(self): |
| """Read terminal status line: Data Set Ready""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) |
| return struct.unpack('I', s)[0] & TIOCM_DSR != 0 |
| |
| @property |
| def ri(self): |
| """Read terminal status line: Ring Indicator""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) |
| return struct.unpack('I', s)[0] & TIOCM_RI != 0 |
| |
| @property |
| def cd(self): |
| """Read terminal status line: Carrier Detect""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str) |
| return struct.unpack('I', s)[0] & TIOCM_CD != 0 |
| |
| # - - platform specific - - - - |
| |
| @property |
| def out_waiting(self): |
| """Return the number of bytes currently in the output buffer.""" |
| #~ s = fcntl.ioctl(self.fd, termios.FIONREAD, TIOCM_zero_str) |
| s = fcntl.ioctl(self.fd, TIOCOUTQ, TIOCM_zero_str) |
| return struct.unpack('I', s)[0] |
| |
| def fileno(self): |
| """\ |
| For easier use of the serial port instance with select. |
| WARNING: this function is not portable to different platforms! |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| return self.fd |
| |
| def set_input_flow_control(self, enable=True): |
| """\ |
| Manually control flow - when software flow control is enabled. |
| This will send XON (true) or XOFF (false) to the other device. |
| WARNING: this function is not portable to different platforms! |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| if enable: |
| termios.tcflow(self.fd, termios.TCION) |
| else: |
| termios.tcflow(self.fd, termios.TCIOFF) |
| |
| def set_output_flow_control(self, enable=True): |
| """\ |
| Manually control flow of outgoing data - when hardware or software flow |
| control is enabled. |
| WARNING: this function is not portable to different platforms! |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| if enable: |
| termios.tcflow(self.fd, termios.TCOON) |
| else: |
| termios.tcflow(self.fd, termios.TCOOFF) |
| |
| def nonblocking(self): |
| """DEPRECATED - has no use""" |
| import warnings |
| warnings.warn("nonblocking() has no effect, already nonblocking", DeprecationWarning) |
| |
| |
| class PosixPollSerial(Serial): |
| """\ |
| Poll based read implementation. Not all systems support poll properly. |
| However this one has better handling of errors, such as a device |
| disconnecting while it's in use (e.g. USB-serial unplugged). |
| """ |
| |
| def read(self, size=1): |
| """\ |
| Read size bytes from the serial port. If a timeout is set it may |
| return less characters as requested. With no timeout it will block |
| until the requested number of bytes is read. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| read = bytearray() |
| timeout = Timeout(self._timeout) |
| poll = select.poll() |
| poll.register(self.fd, select.POLLIN | select.POLLERR | select.POLLHUP | select.POLLNVAL) |
| poll.register(self.pipe_abort_read_r, select.POLLIN | select.POLLERR | select.POLLHUP | select.POLLNVAL) |
| if size > 0: |
| while len(read) < size: |
| # print "\tread(): size",size, "have", len(read) #debug |
| # wait until device becomes ready to read (or something fails) |
| for fd, event in poll.poll(None if timeout.is_infinite else (timeout.time_left() * 1000)): |
| if fd == self.pipe_abort_read_r: |
| break |
| if event & (select.POLLERR | select.POLLHUP | select.POLLNVAL): |
| raise SerialException('device reports error (poll)') |
| # we don't care if it is select.POLLIN or timeout, that's |
| # handled below |
| if fd == self.pipe_abort_read_r: |
| os.read(self.pipe_abort_read_r, 1000) |
| break |
| buf = os.read(self.fd, size - len(read)) |
| read.extend(buf) |
| if timeout.expired() \ |
| or (self._inter_byte_timeout is not None and self._inter_byte_timeout > 0) and not buf: |
| break # early abort on timeout |
| return bytes(read) |
| |
| |
| class VTIMESerial(Serial): |
| """\ |
| Implement timeout using vtime of tty device instead of using select. |
| This means that no inter character timeout can be specified and that |
| the error handling is degraded. |
| |
| Overall timeout is disabled when inter-character timeout is used. |
| |
| Note that this implementation does NOT support cancel_read(), it will |
| just ignore that. |
| """ |
| |
| def _reconfigure_port(self, force_update=True): |
| """Set communication parameters on opened port.""" |
| super(VTIMESerial, self)._reconfigure_port() |
| fcntl.fcntl(self.fd, fcntl.F_SETFL, 0) # clear O_NONBLOCK |
| |
| if self._inter_byte_timeout is not None: |
| vmin = 1 |
| vtime = int(self._inter_byte_timeout * 10) |
| elif self._timeout is None: |
| vmin = 1 |
| vtime = 0 |
| else: |
| vmin = 0 |
| vtime = int(self._timeout * 10) |
| try: |
| orig_attr = termios.tcgetattr(self.fd) |
| iflag, oflag, cflag, lflag, ispeed, ospeed, cc = orig_attr |
| except termios.error as msg: # if a port is nonexistent but has a /dev file, it'll fail here |
| raise serial.SerialException("Could not configure port: {}".format(msg)) |
| |
| if vtime < 0 or vtime > 255: |
| raise ValueError('Invalid vtime: {!r}'.format(vtime)) |
| cc[termios.VTIME] = vtime |
| cc[termios.VMIN] = vmin |
| |
| termios.tcsetattr( |
| self.fd, |
| termios.TCSANOW, |
| [iflag, oflag, cflag, lflag, ispeed, ospeed, cc]) |
| |
| def read(self, size=1): |
| """\ |
| Read size bytes from the serial port. If a timeout is set it may |
| return less characters as requested. With no timeout it will block |
| until the requested number of bytes is read. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| read = bytearray() |
| while len(read) < size: |
| buf = os.read(self.fd, size - len(read)) |
| if not buf: |
| break |
| read.extend(buf) |
| return bytes(read) |
| |
| # hack to make hasattr return false |
| cancel_read = property() |
