From 012b18554e5e6a408a11a7157a30c5d068f2d3d1 Mon Sep 17 00:00:00 2001
From: Arthur de Jong <arthur@arthurdejong.org>
Date: Sat, 30 Mar 2013 22:59:57 +0100
Subject: Initial version of a chsh.ldap utility

---
 utils/shells.py | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 utils/shells.py

(limited to 'utils/shells.py')

diff --git a/utils/shells.py b/utils/shells.py
new file mode 100644
index 0000000..cc3fca1
--- /dev/null
+++ b/utils/shells.py
@@ -0,0 +1,64 @@
+# 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)
-- 
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