Using sudo with Python script

Question

I\'m trying to write a small script to mount a VirtualBox shared folder each time I execute the script. I want to do it with Python, because I\'m trying to learn it for scri

Answer 1

sometimes require a carriage return:

os.popen("sudo -S %s"%(command), 'w').write('mypass\n')

Answer 2

• Use -S option in the sudo command which tells to read the password from 'stdin' instead of the terminal device.

• Tell Popen to read stdin from PIPE.

• Send the Password to the stdin PIPE of the process by using it as an argument to communicate method. Do not forget to add a new line character, '\n', at the end of the password.

sp = Popen(cmd , shell=True, stdin=PIPE)
out, err = sp.communicate(_user_pass+'\n')   

Answer 3

subprocess.Popen creates a process and opens pipes and stuff. What you are doing is:

• Start a process sudo -S
• Start a process mypass
• Start a process mount -t vboxsf myfolder /home/myuser/myfolder

which is obviously not going to work. You need to pass the arguments to Popen. If you look at its documentation, you will notice that the first argument is actually a list of the arguments.

Answer 4

To pass the password to sudo's stdin:

#!/usr/bin/env python
from subprocess import Popen, PIPE

sudo_password = 'mypass'
command = 'mount -t vboxsf myfolder /home/myuser/myfolder'.split()

p = Popen(['sudo', '-S'] + command, stdin=PIPE, stderr=PIPE,
          universal_newlines=True)
sudo_prompt = p.communicate(sudo_password + '\n')[1]

Note: you could probably configure passwordless sudo or SUDO_ASKPASS command instead of hardcoding your password in the source code.

Answer 5

I know it is always preferred not to hardcode the sudo password in the script. However, for some reason, if you have no permission to modify /etc/sudoers or change file owner, Pexpect is a feasible alternative.

Here is a Python function sudo_exec for your reference:

import platform, os, logging
import subprocess, pexpect

log = logging.getLogger(__name__)

def sudo_exec(cmdline, passwd):
    osname = platform.system()
    if osname == 'Linux':
        prompt = r'\[sudo\] password for %s: ' % os.environ['USER']
    elif osname == 'Darwin':
        prompt = 'Password:'
    else:
        assert False, osname

    child = pexpect.spawn(cmdline)
    idx = child.expect([prompt, pexpect.EOF], 3)
    if idx == 0: # if prompted for the sudo password
        log.debug('sudo password was asked.')
        child.sendline(passwd)
        child.expect(pexpect.EOF)
return child.before