import socket
import paramiko
import threading
import sys
import subprocess

# using the key from the Paramiko demo files
host_key = paramiko.RSAKey(filename='test_rsa.key')

class Server (paramiko.ServerInterface):
    def _init_(self):
        self.event = threading.Event()

    def check_channel_request(self, kind, chanid):
        if kind == 'session':
            return paramiko.OPEN_SUCCEEDED
        return paramiko.OPEN_FAILED_ADMINISTRATIVELY_PROHIBITED

    def check_auth_password(self, username, password):
        if (username == 'justin') and (password == 'lovesthepython'):
            return paramiko.AUTH_SUCCESSFUL
        return paramiko.AUTH_FAILED

server = sys.argv[1]
ssh_port = int(sys.argv[2])

try:
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sock.bind((server, ssh_port))
    sock.listen(100)
    print('[+] Listening for connection ...')
    client, addr = sock.accept()

except Exception as e:
    print('[-] Listen failed: ' + str(e))
    sys.exit(1)

print('[+] Got a connection!')

try:
    bhSession = paramiko.Transport(client)
    bhSession.add_server_key(host_key)
    server = Server()

    try:
        bhSession.start_server(server=server)
    except paramiko.SSHException as x:
        print('[-] SSH negotiation failed.')

    chan = bhSession.accept(20)
    print('[+] Authenticated!')
    print(chan.recv(1024).decode())
    chan.send('Welcome to bh_ssh')

    while True:
        try:
            command = chan.recv(1024).decode().strip('\n')
            print('$ ' + command)
            if command != 'exit':
                cmd_output = subprocess.check_output(command, shell=True)
                chan.send(str(cmd_output))
                print(cmd_output.decode())
            else:
                chan.send('exit')
                print('exiting')
                bhSession.close()
                raise Exception ('exit')
        except KeyboardInterrupt:
            bhSession.close()
except Exception as e:
    exc_type, exc_obj, tb = sys.exc_info()
    lineno = tb.tb_lineno
    print('[-] Caught exception: ' + str(e) + ' on line ' + str(lineno))
    try:
        bhSession.close()
    except:
        pass
    sys.exit(1)