Python TTY Control

Question

I guess I'm not clear on what what the function of the getty/agetty/mgetty programs are on a linux/unix machine. I can start a shell on a tty with something like this:

TTY = '/dev/tty3'

cpid = os.fork()
if cpid == 0:
    os.closerange(0, 4)
    sys.stdin = open(TTY, 'r')
    sys.stdout = open(TTY, 'w')
    sys.stderr = open(TTY, 'w')
    os.execv(('/bin/bash',), ('bash',))

..and if i switch over to tty3, there is a shell running- but some keystrokes are ignored / are never being sent to the shell. the shell knows the TTY settings are not correct because bash will say something like 'unable to open tty, job control disabled'

I know the 'termios' module has functions to change the settings on the TTY, which is what the 'tty' module uses, but i am unable to find an example of python setting the TTY correctly and starting a shell. I feel like it should be something simple, but i don't know where to look.

looking at the source for the *etty programs didn't help me- C looks like greek to me :-/

Maybe im just not looking for the right terms? Anyone replaced the *etty programs with Python in the past and have an explanation they would care to share?

Thanks for entertaining my basic question :)