pid = os.fork()
if pid == 0:
    exe = sys.executable
    os.execlp(exe, os.path.basename(exe))
    os._exit(127)

os.waitpid(pid, 0)

20:18:26 --- SIGINT {si_signo=SIGINT, si_code=SI_USER, si_pid=4678, si_uid=1000} ---
20:18:26 rt_sigreturn({mask=[]})        = -1 EINTR (Interrupted system call) <0.000007>
20:18:26 write(4, "\33[?2004l", 8)      = 8 <0.000013>
20:18:26 write(4, "\33[?1l\33>", 7)     = 7 <0.000012>
20:18:26 ioctl(3, TCGETS, {c_iflag=IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0 <0.000008>
20:18:26 ioctl(3, TCGETS, {c_iflag=IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = 0 <0.000006>
20:18:26 ioctl(3, TCSETSW, {c_iflag=ICRNL|IXON|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|OPOST|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ICANON|ECHO|ECHOE|ECHOK|IEXTEN|ECHOCTL|ECHOKE, ...}) = -1 EIO (Input/output error) <0.000007>
...
20:18:26 ioctl(3, TCSETSW, {c_iflag=BRKINT|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ECHOE|ECHOK|ECHOCTL|ECHOKE, ...}) = -1 EIO (Input/output error) <0.000008>

...
20:18:26 ioctl(3, TCSETSW, {c_iflag=BRKINT|IUTF8, c_oflag=NL0|CR0|TAB0|BS0|VT0|FF0|ONLCR, c_cflag=B38400|CS8|CREAD, c_lflag=ISIG|ECHOE|ECHOK|ECHOCTL|ECHOKE, ...}) = -1 EIO (Input/output error) <0.000008>

sudo strace -e inject=ioctl:error=5 -p $(pidof python)

# sudo ./retsnoop -x EIO -a '*tty*' -e '*tty*'

10:10:44.178847 -> 10:10:44.178850 TID/PID 30657/30657 (python/python):

                 entry_SYSCALL_64_after_hwframe+0x76  
                 do_syscall_64+0x7e                   
                 x64_sys_call+0x131e                  
                 __x64_sys_ioctl+0xa4                 
     2us [-EIO]  tty_ioctl+0x515                      
 ⌇   1us [-EIO]  n_tty_ioctl+0x85                     
 ⌇   1us [-EIO]  n_tty_ioctl_helper+0x2d              
 ⌇   0us [-EIO]  tty_mode_ioctl+0x1c1                 
                 set_termios+0x5d                     
 ⌇   0us [-EIO]  tty_check_change+0x13                
!⌇   0us [-EIO]  __tty_check_change 

int tty_check_change(struct tty_struct *tty)
{
  return __tty_check_change(tty, SIGTTOU);
}
int __tty_check_change(struct tty_struct *tty, int sig)
{
  if (tty_pgrp && pgrp != tty_pgrp) {
    if (is_ignored(sig)) {
      if (sig == SIGTTIN)
        ret = -EIO;
    } else if (is_current_pgrp_orphaned())
      ret = -EIO;

#!/usr/bin/env python3
import os, sys, pty, fcntl, termios, signal, time

def handler(sig, f):
    pass

def spawn_p2():
    master_fd, slave_fd = pty.openpty()
    os.setsid()
    fcntl.ioctl(slave_fd, termios.TIOCSCTTY, 0)

    p2_pgid = os.getpgrp()

    pid3 = os.fork()
    if pid3 == 0:
        os.setpgid(0, 0)
        os.dup2(slave_fd, 0)
        os.dup2(slave_fd, 1)
        os.dup2(slave_fd, 2)
        if slave_fd > 2:
            os.close(slave_fd)
        pid4 = os.fork()
        if pid4 == 0:
            signal.signal(signal.SIGTTOU, handler)
            exe = 'python'
            os.execlp(exe, os.path.basename(exe))
        else:
            os.tcsetpgrp(0, p2_pgid)
            os._exit(0)

    try:
        os.setpgid(pid3, pid3)
    except ProcessLookupError:
        pass

    os.tcsetpgrp(slave_fd, pid3)

    if slave_fd > 2:
        os.close(slave_fd)

    os.waitpid(pid3, 0)
    time.sleep(1)

    os.tcsetpgrp(master_fd, p2_pgid)

    while 1:
        os.read(master_fd, 1024)

def main():
    pid2 = os.fork()
    if pid2 == 0:
        spawn_p2()
    else:
        time.sleep(1 << 30)

if __name__ == "__main__":
    main()

root       67924   67901  1 13:49 pts/0    00:00:00  \_ python /src/orp_repl2.py
root       67977   67924  1 13:49 pts/1    00:00:00      \_ python /src/orp_repl2.py
root       67979   67924 79 13:49 pts/1    00:00:02      \_ python