JCaselles user finder v3 - spwd module 20130717-173930

Assignment

Write a code that will print the list of available user to log in.

Solution

Use of spwd module, that returns a list of the databases of all users whith proper shell init configuration (i.e. they don't haver either /bin/false or /sbin/nologin). From this list, there still are few that are not able to be used for login, and are marked with "*" or "!" in the password index of the database (ps_pwd, or 1). When we discard those with this symbols in the password field, we end up with only those users capable of login.

Link to Code at GitHub

#!/usr/bin/env python

from spwd import getspall
from sys import exit

def get_users_list ():

    """
    This function prints the list of users that are able to login
    into the system. To achieve this, we use the spwd module and its function
    getspall(), which returns a list of each user password database,
    like /etc/shadow file. Then we filter it to print just the users
    that have a proper password, and not marked with "*" or "!", which means
    they are not suited for login into the system.

    """


    user_list = getspall()

    filtered_list =  [user.sp_nam for user in user_list \
                      if user.sp_pwd.find("*") == -1 \
                      and user.sp_pwd.find("!") == -1]

    for x in filtered_list:
        print x


if __name__ == "__main__":
    get_users_list()
    exit(0)