tunnel.py 文件源码

def _try_passwordless_openssh(server, keyfile):
    """Try passwordless login with shell ssh command."""
    if pexpect is None:
        raise ImportError("pexpect unavailable, use paramiko")
    cmd = 'ssh -f '+ server
    if keyfile:
        cmd += ' -i ' + keyfile
    cmd += ' exit'

    # pop SSH_ASKPASS from env
    env = os.environ.copy()
    env.pop('SSH_ASKPASS', None)

    ssh_newkey = 'Are you sure you want to continue connecting'
    p = pexpect.spawn(cmd, env=env)
    while True:
        try:
            i = p.expect([ssh_newkey, _password_pat], timeout=.1)
            if i==0:
                raise SSHException('The authenticity of the host can\'t be established.')
        except pexpect.TIMEOUT:
            continue
        except pexpect.EOF:
            return True
        else:
            return False