environment/lib/python2.7/site-packages/IPython/external/pexpect/_pexpect.py
def __pty_make_controlling_tty(self, tty_fd):

        """This makes the pseudo-terminal the controlling tty. This should be
        more portable than the pty.fork() function. Specifically, this should
        work on Solaris. """

        child_name = os.ttyname(tty_fd)

        # Disconnect from controlling tty. Harmless if not already connected.
        try:
            fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY);
            if fd >= 0:
                os.close(fd)
        except:
            # Already disconnected. This happens if running inside cron.
            pass

        os.setsid()

        # Verify we are disconnected from controlling tty
        # by attempting to open it again.
        try:
            fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY);
            if fd >= 0:
                os.close(fd)
                raise ExceptionPexpect, "Error! Failed to disconnect from controlling tty. It is still possible to open /dev/tty."
        except:
            # Good! We are disconnected from a controlling tty.
            pass

        # Verify we can open child pty.
        fd = os.open(child_name, os.O_RDWR);
        if fd < 0:
            raise ExceptionPexpect, "Error! Could not open child pty, " + child_name
        else:
            os.close(fd)

        # Verify we now have a controlling tty.
        fd = os.open("/dev/tty", os.O_WRONLY)
        if fd < 0:
            raise ExceptionPexpect, "Error! Could not open controlling tty, /dev/tty"
        else:
            os.close(fd)
def __pty_make_controlling_tty(self, tty_fd):

        """This makes the pseudo-terminal the controlling tty. This should be
        more portable than the pty.fork() function. Specifically, this should
        work on Solaris. """

        child_name = os.ttyname(tty_fd)

        # Disconnect from controlling tty. Harmless if not already connected.
        try:
            fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY);
            if fd >= 0:
                os.close(fd)
        except:
            # Already disconnected. This happens if running inside cron.
            pass

        os.setsid()

        # Verify we are disconnected from controlling tty
        # by attempting to open it again.
        try:
            fd = os.open("/dev/tty", os.O_RDWR | os.O_NOCTTY);
            if fd >= 0:
                os.close(fd)
                raise ExceptionPexpect, "Error! Failed to disconnect from controlling tty. It is still possible to open /dev/tty."
        except:
            # Good! We are disconnected from a controlling tty.
            pass

        # Verify we can open child pty.
        fd = os.open(child_name, os.O_RDWR);
        if fd < 0:
            raise ExceptionPexpect, "Error! Could not open child pty, " + child_name
        else:
            os.close(fd)

        # Verify we now have a controlling tty.
        fd = os.open("/dev/tty", os.O_WRONLY)
        if fd < 0:
            raise ExceptionPexpect, "Error! Could not open controlling tty, /dev/tty"
        else:
            os.close(fd)
This makes the pseudo-terminal the controlling tty. This should be
        more portable than the pty.fork() function. Specifically, this should
        work on Solaris.