1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
# coding: utf-8
# shells.py - functions for validating user shells
#
# Copyright (C) 2013 Arthur de Jong
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301 USA
import ctypes
import ctypes.util
import os
import sys
def list_shells():
"""List the shells from /etc/shells."""
libc = ctypes.CDLL(ctypes.util.find_library("c"))
libc.setusershell()
while True:
shell = ctypes.c_char_p(libc.getusershell()).value
if not shell:
break
yield shell
libc.endusershell()
def shellexists(shell):
"""Check if the provided shell exists and is executable."""
return os.path.isfile(shell) and os.access(shell, os.X_OK)
def check(shell, asroot=False):
"""Check if the specified shell is valid and exit if it isn't."""
# if the shell is listed in /etc/shells, everything should be OK
if shell in list_shells():
return
# if we are not root, bail out
if not asroot:
if not shell:
# FIXME: print to stderr
print '%s: empty shell not allowed' % sys.argv[0]
else:
# FIXME: print to stderr
print '%s: %s is an invalid shell' % (sys.argv[0], shell)
sys.exit(1)
# warn if something seems wrong
if not shell:
# FIXME: print to stderr
print '%s: Warning: setting empty shell' % sys.argv[0]
elif not shellexists(shell):
print '%s: Warning: %s does not exist' % (sys.argv[0], shell)
|