How to connect to virtual /dev/ttyX from same machines pts terminal?

Question

I want to get output/input from /dev/ttyX console (normally accessible directly using keys ctrl+alt+FNr, where Nr is number of /dev/ttyNr: ctrl+alt+f4 access /dev/tty4). I want to view and control these consoles over ssh (which normally uses virtual /dev/pts console like desktop applications (xterm) does). I need something to either connect from normal virtual terminal (/dev/pts/Y) to /dev/ttyX, or switch consoles.

For physical devices like /dev/ttySX, /dev/ttyUSBX utilities like minicom and screen after setting baud rate are working well. I tried to apply similar methods for virtual /dev/ttyX but sessions only hang: output send from screen gets to tty, but are not executed and input does show (ctrl+alt+f4 shows output but it does not get executed, neither while writing anything shows up in screen: like I would be using echo nonsense >> /dev/tty4 but not having real session). minicom does the same. Either I am abusing utilities or I don't know how to properly setup tty's.

Should I do something with getty? It seems that it is important here too.

Any ideas how to connect to /dev/tty from pts console? I am using Linux with systemd if that is important.

Answer 1

Why? :) The /dev/ttyX terminals are just software terminals provided by the kernel. The /dev/pts/* terminals are essentially pipes connected to /dev/ptmx, and according to man pts on my closest-available RHEL6 system, the interface is identical between the two. If you're implementing a program to replace a terminal interface, using /dev/ptmx is the generally "right" way to do it anyway. On a Linux system, the filename is all that really differs. You could probably just create a symlink named like /dev/ttyX after creating the pty if the filename is really that important.

If your goal is to remotely control the screen attained when you hit Alt+F4, for example, just change /etc/iniitab to open your alternate "remote control" program on /dev/tty4. Normally it starts up a mingetty, but there's no reason you couldn't run whatever you want there. You may also look at the mingetty man page to see what else you can do with mingetty; it's capable of several interesting things.