def reset_invalid_value(opt):
logsyslog(LOG_ERR,
('{conf}: Invalid value for ' +
'{option}').format(
conf = self.config_file,
option = opt))
return getattr(self, opt)
def start(self):
"""
Load config, daemonize, connect to serial port, listen on socket
"""
opensyslog(ident = self.name, facility = LOG_DAEMON)
self.__load_config()
if self.pidfile_path is not None:
self.daemon_context.pidfile = lockfile.FileLock(self.pidfile_path)
if _pidfile_isbusy(self.daemon_context.pidfile):
logsyslog(LOG_ERR, 'Already running (pidfile is locked)')
closesyslog()
return
if _socket_isbusy(self.socket_path):
logsyslog(LOG_ERR, 'Already running (socket is in use)')
closesyslog()
return
self.daemon_context.open()
with _openfile(self.daemon_context.pidfile.path, 'w',
fail = self.__stop) as file:
file.write('{pid}'.format(pid = os.getpid()))
# opening the serial port here doesn't work
# open it in __run instead
# self.serial_context.open()
logsyslog(LOG_INFO, 'Started')
self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
self.socket.bind(self.socket_path)
self.socket.listen(1)
logsyslog(LOG_INFO, ('Listening on socket {socket}').format(
socket = self.socket_path))
self.__run()
def _openfile(path, mode = 'r', fail = None):
path = os.path.realpath(path)
try:
file = open(path, mode)
except IOError as error:
if repr(error).find('Permission') >= 0:
logsyslog(LOG_ERR,
'Cannot {action} {path}. Permission denied.'.format(
action = ('write to' if 'w' in mode else 'read'),
path = path))
elif repr(error).find('No such file') >= 0:
logsyslog(LOG_ERR, 'No such file or directory: {path}'.format(
path = path))
else:
logsyslog(LOG_ERR, 'Cannot {action} {path}. Unknown error.'.format(
action = ('write to' if 'w' in mode else 'read'),
path = path))
else:
return file
if fail is not None:
fail()
sys.exit(255)
return None
def __stop(self):
pid = _get_pid(self.daemon_context.pidfile.path)
if pid is None:
return
logsyslog(LOG_INFO, 'Stopping')
os.remove(self.socket.getsockname())
os.remove(self.daemon_context.pidfile.path)
self.socket.close()
if self.serial_context.isOpen():
self.serial_context.close()
self.daemon_context.close()
try:
os.kill(pid, signal.SIGKILL)
except OSError:
logsyslog(LOG_ERR, 'Could not stop process id {pid}'.format(
pid = pid))
closesyslog()
def __accept_signal(self, sig, frame):
if sig == signal.SIGHUP:
self.__load_config()
else:
logsyslog(LOG_INFO, 'Caught signal {sig}'.format(sig = sig))
self.__stop()
def __load_config(self):
def reset_invalid_value(opt):
logsyslog(LOG_ERR,
('{conf}: Invalid value for ' +
'{option}').format(
conf = self.config_file,
option = opt))
return getattr(self, opt)
conf = _openfile(self.config_file, 'r')
if conf is not None:
with conf:
regex_pat = regex.compile(r"""\s* (?|
(?P<option>
reply_length_strict |
data[-_]length |
data[-_]encoding |
log[-_]file |
pidfile[-_]path |
socket[-_]path
) \s* (?: =\s* )?
(?|
" (?P<value> [^"]+ ) " |
' (?P<value> [^']+ ) ' |
(?P<value> [^#\r\n]+ )
) )
""", regex.X|regex.I)
line_num = 0
for line in conf:
line_num += 1
if line.startswith('#'):
continue
match = regex_pat.match(line.strip())
if match:
# translate the option name to the object's attribute
opt = match.group('option').lower().replace('-', '_')
if opt.endswith(('file',
'dir',
'path',
'encoding')):
# value is a string
val = match.group('value')
elif opt == 'reply_length_strict':
# value must be a boolean
if val.lower() not in ['0', '1', 'false', 'true']:
val = reset_invalid_value(opt)
elif val.lower() in ['0', 'false']:
val = False
else:
val = True
else:
# value must be numeric and positive
val = int(match.group('value'))
if val <= 0:
val = reset_invalid_value(opt)
setattr(self, opt, val)
else:
logsyslog(LOG_ERR, ('{conf}: Invalid syntax at line ' +
'{line}').format(
conf = self.config_file,
line = line_num))
logsyslog(LOG_INFO, 'Loaded configuration from {conf}'.format(
conf = self.config_file))
def __run(self):
with open(self.log_file, 'a') as log_file:
try:
soc = None
# flush doesn't work in daemon mode for ttyS?
# close and reopen instead
device = self.serial_context.port
is_ttyS = True
try:
# is it a number? Serial defaults to /dev/ttyS? if so
device += 0
except TypeError:
# not a number, assume string
try:
if not device.startswith('/dev/ttyS'):
raise AttributeError
except AttributeError:
# not a string or not a ttyS? device
# assume flushing works
is_ttyS = False
else:
device = '/dev/ttyS{num}'.format(num = device)
while True:
if not soc or soc.fileno() < 0:
logsyslog(LOG_INFO, 'Waiting for connection')
soc, soc_addr = self.socket.accept()
logsyslog(LOG_INFO, ('Connected to {addr}').format(
addr = soc_addr))
data = soc.recv(self.data_length).decode(
self.data_encoding)
if data == '':
logsyslog(LOG_INFO, 'Closing connection')
soc.close()
continue
elif data == 'device':
logsyslog(LOG_INFO, 'Device path requested')
try:
soc.sendall(device.encode(self.data_encoding))
except ConnectionResetError:
soc.close()
continue
logsyslog(LOG_INFO, 'Read from socket: {data}'.format(
data = data))
reply_length_byte_length = 0
try:
reply_length_byte_length = int(data[0], 16)
reply_length = int(
data[1 : reply_length_byte_length + 1], 16)
except ValueError:
reply_length = 0
data = data[reply_length_byte_length + 1:]
if not self.serial_context.isOpen():
# first time in the loop
logsyslog(LOG_INFO, 'Opening serial port')
self.serial_context.open()
logsyslog(LOG_INFO, 'Sending {data}'.format(
data = data))
# discard any input or output
self.serial_context.flushOutput()
self.serial_context.flushInput()
self.serial_context.write(data.encode(self.data_encoding))
if is_ttyS:
self.serial_context.close()
self.serial_context.open()
else:
self.serial_context.flush()
logsyslog(LOG_INFO, ('Will read {length} bytes').format(
length = reply_length))
if reply_length > 0:
reply = self.serial_context.read(reply_length)
reply_decoded = reply.decode(self.data_encoding)
logsyslog(LOG_INFO, 'Received {data}'.format(
data = reply_decoded))
if len(reply_decoded) == reply_length \
or not self.reply_length_strict:
try:
soc.sendall(reply)
except ConnectionResetError:
soc.close()
continue
except:
traceback.print_exc(file = log_file)
self.__stop()
