Member Avatar for ganeshredcobra

am using debian lenny and tried to create a shutdwon script using python

import os
os.system("sudo shutdown -h now")

i cant use this in debian lenny then how will i implement

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Your GUI app is failing because sudo expects a terminal to prompt for a password. From a GUI there is no TTY, so os.system("sudo ...") quietly does nothing. is right: keep root access tight. Two clean approaches on Debian Lenny are below.

  1. Ask ConsoleKit to power off over D-Bus (PolicyKit will raise a GUI auth dialog if needed). This avoids calling shutdown directly and works well in desktop sessions.
import dbus
bus = dbus.SystemBus()
ck = bus.get_object('org.freedesktop.ConsoleKit',
                    '/org/freedesktop/ConsoleKit/Manager')
iface = dbus.Interface(ck, 'org.freedesktop.ConsoleKit.Manager')
iface.Stop()  # requests system shutdown; polkit handles auth

Notes:

  • You need a polkit agent running in your session (e.g., the GNOME/KDE one) so the password dialog appears. ConsoleKit exposes Stop() and Restart() for this exact use case. See the ConsoleKit Manager API. ConsoleKit Manager API
  1. Keep using shutdown, but supply a GUI askpass helper to sudo as @Furdo hinted.

Create ~/bin/askpass.sh:

#!/bin/sh
zenity --password --title="Authentication"

Then call it from Python:

import os, subprocess
env = os.environ.copy()
env['SUDO_ASKPASS'] = os.path.expanduser('~/bin/askpass.sh')
subprocess.check_call(['sudo', '-A', '/sbin/shutdown', '-h', 'now'], env=env)

The -A flag tells sudo to use the askpass helper; SUDO_ASKPASS points to your script. Details are in the sudo manual. Sudo manual

Extras:

  • If you want a ready-made GUI prompt on Lenny, gksu/gksudo exists and will pop up a password dialog for /sbin/shutdown. gksu package (includes Lenny)
  • For a one-click button without prompts, use visudo to grant only your user NOPASSWD for /sbin/shutdown (and/or /sbin/reboot). Be precise with paths and avoid broad rules.

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All 5 Replies

Member Avatar for woooee

i cant use this in debian lenny

I don't understand why you can't use this. Also, you probably only want root access for the script, otherwise anyone can shut down your system. If you want to run it from a non-root user, then you or the program will also have to be able to supply the correct password, which also is a bad idea.

Edited by woooee because: n/a
Member Avatar for SoulMazer

Could you be more descriptive than "I can't use this"? Do you get an error? Does it just not do anything in general?

As you probably know, you need elevated privileges to run a command with "sudo," so my guess is that you need to run your script with "sudo": sudo python MyScript.py

Member Avatar for ganeshredcobra

this is working if am going through terminal but here am using a gui so after running the script its not promting for password and its not getting shutdown

choice=='Shutdown':
msgbox("You chose to Shutdown")
msg = "Do you want to schedule your Shutdown"
title = "Confirmation"
choices=
choice=buttonbox(msg,title,choices)
if choice=='Yes':
t=integerbox('Enter the time in minutes :')
tim=t*60
time.sleep(tim)
#os.system('sudo shutdown -h now')
commands.getoutput('sudo shutdown -r now')
else:
os.system('sudo shutdown -h now')

Member Avatar for Furdo

You can or at least used to be able to shutdown in python using python dbus Hal.
The following works in Slackware 13 Mandriva and Fedora.

import dbus
bus = dbus.SystemBus()
shut = bus.get_object('org.freedesktop.Hal',
                       '/org/freedesktop/Hal/devices/computer')
shutr =  dbus.Interface(shut , 'org.freedesktop.Hal.Device.SystemPowerManagement')
shutr.Shutdown()

But dbus is a can of worms and constantly changing giving us in linux all the joys of the Windows registry. So in ubuntu 10.10 hal has disappeared and UPower has appeared at least in the default installation. I can no longer shutdown but with UPower I can Hibernate or Suspend. The following works in Ubuntu 10.10 for me (of course some hardware setups have problems with hibernate).

import dbus
bus = dbus.SystemBus()
shut = bus.get_object('org.freedesktop.UPower',
        '/org/freedesktop/UPower') 
shutr =   dbus.Interface(shut , 'org.freedesktop.UPower')
shutr.Hibernate()

To just use halt or shutdown explore sudo -A and SUDO_ASKPASS
with say a simple little pygtk or pyqt dialog to get the password.

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