set terminal size via CSI query

termsize.py

#!/usr/bin/python3
import sys
import os
import tty
import termios
import re
import struct
import fcntl

stdin = sys.stdin.fileno()
stdout = sys.stdout.fileno()

prevattr = termios.tcgetattr(stdin)
try:
    tty.setcbreak(stdin)
    os.write(stdout, b'\033[18;t')
    reply = os.read(stdin, 256)
finally:
    termios.tcsetattr(stdin, termios.TCSANOW, prevattr)

m = re.match(rb'^\033\[8;(?P<rows>\d+);(?P<cols>\d+)t$', reply)
if m:
    rows, cols = int(m.group("rows").decode("ASCII")), int(m.group("cols").decode("ASCII"))
    args = struct.pack('HHHH', rows, cols, 0, 0)
    fcntl.ioctl(stdin, termios.TIOCSWINSZ, args)
else:
    sys.stderr.write("terminal size query failed\n")
    sys.exit(1)