I have written an SSH wrapper script that does local line editing. It is invoked similarly to SSH. For example: python3 sshwrapper.py user@example.com -CX. The problem is that when I connect to a remote computer using this script and use vim or tmux there, some garbage is printed. This problem is not specific to SSH, since the problems also appear when I use this script to wrap bash instead of ssh.
Examples:
After starting
tmux, some garbage is printed after the bash prompt:abc@me:~$ ^[[?65;1;9cWhen opening a new file in Vim using
vim mynewfile.txt, this appears on the first line:^[[2;2R^[[>65;6003;1c^[]10;rgb:0000/0000/0000^G^[]11;rgb:ffff/ffff/dddd^G
How do I fix the problem?
This is the script in question:
import os
import pty
import select
import signal
import subprocess
import sys
master_fd, slave_fd = pty.openpty()
process = subprocess.Popen(['ssh'] + sys.argv[1:],
stdin=slave_fd,
stdout=slave_fd,
stderr=subprocess.STDOUT,
# Important for Ctrl-c in the remote terminal.
preexec_fn=os.setsid)
def sigint_handler(_signum, _frame):
os.write(master_fd, b'\03') # Send Ctrl-c.
signal.signal(signal.SIGINT, sigint_handler)
def sigtstp_handler(_signum, _frame):
os.write(master_fd, b'\x1A') # Send Ctrl-z.
signal.signal(signal.SIGTSTP, sigtstp_handler)
def sigchld_handler(_signum, _frame):
process.wait()
sys.exit(process.returncode)
signal.signal(signal.SIGCHLD, sigchld_handler)
while process.poll() is None:
# Block until there is something to read or write.
r, w, e = select.select([sys.stdin, master_fd], [], [])
if sys.stdin in r:
# Write to SSH.
user_input = os.read(sys.stdin.fileno(), 4096)
if not user_input:
os.write(master_fd, b'\04') # Send Ctrl-d.
else:
os.write(master_fd, user_input)
if master_fd in r:
# Read from SSH.
data = os.read(master_fd, 4096)
sys.stdout.write(data.decode())
sys.stdout.flush()
I am using Python 3.8.10 on Ubuntu 20.04 on both my local computer and the remote computer. This is a self-education project, so I am writing the program using Python standard libraries only.
