使用popen和专用的TTY Python运行交互式Bash

I need to run an interactive Bash instance in a separated process in Python with it's own dedicated TTY (I can't use pexpect). I used this code snippet I commonly see used in similar programs:

我需要在Python中使用它自己的专用TTY在一个单独的进程中运行一个交互式Bash实例(我不能使用pexpect)。我使用了这个代码片段,我常见于类似的程序中使用:

master, slave = pty.openpty()

p = subprocess.Popen(["/bin/bash", "-i"], stdin=slave, stdout=slave, stderr=slave)

os.close(slave)

x = os.read(master, 1026)

print x

subprocess.Popen.kill(p)
os.close(master)

But when I run it I get the following output:

但是当我运行它时,我得到以下输出:

$ ./pty_try.py
bash: cannot set terminal process group (10790): Inappropriate ioctl for device
bash: no job control in this shell

Strace of the run shows some errors:

运行的Strace显示一些错误:

...
readlink("/usr/bin/python2.7", 0x7ffc8db02510, 4096) = -1 EINVAL (Invalid argument)
...
ioctl(3, SNDCTL_TMR_TIMEBASE or SNDRV_TIMER_IOCTL_NEXT_DEVICE or TCGETS, 0x7ffc8db03590) = -1 ENOTTY (Inappropriate ioctl for device)
...
readlink("./pty_try.py", 0x7ffc8db00610, 4096) = -1 EINVAL (Invalid argument)

The code snippet seems pretty straightforward, is Bash not getting something it needs? what could be the problem here?

代码片段看起来很简单,Bash没有得到它需要的东西吗?这可能是什么问题?

3 个解决方案

#1

This is a solution to run an interactive command in subprocess. It uses pseudo-terminal to make stdout non-blocking(also some command needs a tty device, eg. bash). it uses select to handle input and ouput to the subprocess.

这是在子进程中运行交互式命令的解决方案。它使用伪终端使stdout非阻塞(也有一些命令需要tty设备,例如bash)。它使用select来处理输入和输出到子进程。

#!/usr/bin/env python
# -*- coding: utf-8 -*-

import os
import sys
import select
import termios
import tty
import pty
from subprocess import Popen

command = 'bash'
# command = 'docker run -it --rm centos /bin/bash'.split()

# save original tty setting then set it to raw mode
old_tty = termios.tcgetattr(sys.stdin)
tty.setraw(sys.stdin.fileno())

# open pseudo-terminal to interact with subprocess
master_fd, slave_fd = pty.openpty()

# use os.setsid() make it run in a new process group, or bash job control will not be enabled
p = Popen(command,
          preexec_fn=os.setsid,
          stdin=slave_fd,
          stdout=slave_fd,
          stderr=slave_fd,
          universal_newlines=True)

while p.poll() is None:
    r, w, e = select.select([sys.stdin, master_fd], [], [])
    if sys.stdin in r:
        d = os.read(sys.stdin.fileno(), 10240)
        os.write(master_fd, d)
    elif master_fd in r:
        o = os.read(master_fd, 10240)
        if o:
            os.write(sys.stdout.fileno(), o)

# restore tty settings back
termios.tcsetattr(sys.stdin, termios.TCSADRAIN, old_tty)

#2

This is the solution that worked for me at the end (as suggested by qarma) :

这是最终对我有用的解决方案(如qarma所示):

libc = ctypes.CDLL('libc.so.6')

master, slave = pty.openpty()
p = subprocess.Popen(["/bin/bash", "-i"], preexec_fn=libc.setsid, stdin=slave, stdout=slave, stderr=slave)
os.close(slave)

... do stuff here ...

x = os.read(master, 1026)
print x

#3

-3

you will have to pass input to read and then print x.

你将不得不传递输入读取然后打印x。

#1