def check_pin(request, account):
""":returns True on success, False on failure"""
if request.card_pin != account.pin:
eprint("wrong pin!")
# eprint("expected '{}', but got '{}'".format(account.pin, request.card_pin))
return False
return True
def create_new_account(request):
""":return True on success, False otherwise"""
if request.account in accounts:
eprint("account name '{}' already exists".format(request.account))
return False
if request.amount < Balance(10 * 100):
eprint("initial balance {} must be at least 10.00".format(
request.amount))
return False
accounts[request.account] = Account(request.card_pin, request.amount)
return True
def deposit(request):
""":return True on success, False otherwise"""
if not check_account_name_exists(request.account):
return False
account = accounts[request.account]
if not check_pin(request, account):
return False
if request.amount <= Balance(0):
eprint("amount {} must be larger than 0.00".format(request.amount))
return False
account.balance += request.amount
return True
def process_request(request):
""":returns True on success, False on failure"""
if request.command == "n":
return accounting.create_new_account(request)
if request.command == "g":
return accounting.check_balance(request)
if request.command == "w":
return accounting.withdraw(request)
if request.command == "d":
return accounting.deposit(request)
eprint("Invalid command '" + request.command +
"'. This shouldn't happen...")
return False # this should never happen
def withdraw(request):
""":return True on success, False otherwise"""
if not check_account_name_exists(request.account):
return False
account = accounts[request.account]
if not check_pin(request, account):
return False
if request.amount <= Balance(0):
eprint("amount {} must be larger than 0.00".format(request.amount))
return False
if account.balance < request.amount:
eprint("balance '{}' not sufficient to withdraw amount '{}'".format(
account.balance, request.amount))
return False
account.balance -= request.amount
return True
def exit_gracefully(signum, frame):
eprint("received SIGINT or SIGTERM, terminating gracefully...")
if conn is not None:
conn.close()
s.close()
sys.exit(0)
def input_error_exit():
eprint("input error exit 255")
sys.exit(255)
if request.command == "g":
return accounting.check_balance(request)
if request.command == "w":
return accounting.withdraw(request)
if request.command == "d":
return accounting.deposit(request)
eprint("Invalid command '" + request.command +
"'. This shouldn't happen...")
return False # this should never happen
if __name__ == '__main__':
args = arguments.read_bank_arguments(sys.argv[1:])
if args is None:
eprint("parsing of bank arguments failed, terminating...")
input_error_exit()
(port, auth_filename) = args
if port is None:
port = constants.DEFAULT_PORT
if auth_filename is None:
auth_filename = "bank.auth"
key = encryption.create_random_key()
eprint("bank key (base64): " + base64.b64encode(key).decode("utf-8"))
auth_file = open(auth_filename, "wb")
auth_file.write(key)
auth_file.close()
myprint("created")
conn = None
def check_account_name_exists(account_name):
""":returns True on success, False on failure"""
if account_name not in accounts:
eprint("account name '{}' doesn't exists".format(account_name))
return False
return True
def main():
args = arguments.read_atm_arguments(sys.argv[1:])
if args is None:
eprint("parsing ATM arguments failed. terminating...")
input_error_exit()
(auth_filename, ip_address, port, card_filename, account_name, command,
amount) = args
if ip_address is None:
ip_address = "127.0.0.1"
if port is None:
port = constants.DEFAULT_PORT
if card_filename is None:
card_filename = account_name + ".card"
if auth_filename is None:
auth_filename = "bank.auth"
pin, key = None, None
try:
if command != "n":
card_file = open(card_filename, 'r')
pin = card_file.read()
card_file.close()
else:
if os.path.isfile(card_filename):
eprint("card file already exists:", card_filename)
input_error_exit()
pin = my_base64encode(encryption.create_random_key())
auth_file = open(auth_filename, 'rb')
key = auth_file.read()
eprint("atm key (base64): " + base64.b64encode(key).decode("utf-8"))
auth_file.close()
except IOError as e:
eprint(e)
input_error_exit()
request = Request.Request(account_name, pin, command, amount)
s = socket.socket()
s.settimeout(10)
try:
s.connect((ip_address, port))
data_to_send = str(request)
eprint("atm, sending (decrypted): " + data_to_send)
encrypted_data_to_send = encryption.encrypt_message(data_to_send, key)
eprint("atm, sending " + str(len(encrypted_data_to_send)) +
" bytes, (encrypted)")
s.send(encrypted_data_to_send)
received_data = s.recv(BUFFER_SIZE)
if not received_data:
s.close()
protocol_error_exit()
decrypted_data = encryption.decrypt_message(received_data, key)
if decrypted_data is None:
s.close()
protocol_error_exit()
else:
if decrypted_data == constants.FAILURE:
eprint("received FAILURE code from bank. terminating...")
s.close()
input_error_exit()
else: # success
eprint("received JSON result from bank")
myprint(decrypted_data)
if command == "n":
card_file = open(card_filename, 'w')
card_file.write(pin)
card_file.close()
except Exception as e:
eprint("socket error:", e)
s.close()
protocol_error_exit()
def protocol_error_exit():
eprint("protocol error exit 63")
sys.exit(63)