lib/privileges.nit

   1 # This file is part of NIT ( http://www.nitlanguage.org ).
   2 #
   3 # Copyright 2013 Alexis Laferrière <alexis.laf@xymus.net>
   4 #
   5 # Licensed under the Apache License, Version 2.0 (the "License");
   6 # you may not use this file except in compliance with the License.
   7 # You may obtain a copy of the License at
   8 #
   9 #     http://www.apache.org/licenses/LICENSE-2.0
  10 #
  11 # Unless required by applicable law or agreed to in writing, software
  12 # distributed under the License is distributed on an "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14 # See the License for the specific language governing permissions and
  15 # limitations under the License.
  16
  17 # Process privileges management utilities
  18 #
  19 # Used mainly by daemons and such to aquire resources as su and
  20 # then drop back to a restricted user.
  21 module privileges
  22
  23 import opts
  24
  25 class UserGroup
  26         var user: String
  27         var group: nullable String
  28
  29         fun drop_privileges
  30         do
  31                 var passwd = new Passwd.from_name(user)
  32                 var uid = passwd.uid
  33
  34                 var group = group
  35                 var gid
  36                 if group != null then
  37                         var gpasswd = new Group.from_name(group)
  38                         gid = gpasswd.gid
  39                 else gid = passwd.gid
  40
  41                 sys.gid = gid
  42                 sys.uid = uid
  43         end
  44 end
  45
  46 # Option to ask for a username and group
  47 class OptionDropPrivileges
  48         super OptionUserAndGroup
  49
  50         init do init_user_and_group("Drop privileges to user:group or simply user", "-u", "--usergroup")
  51 end
  52
  53 # Option to ask for a username and group
  54 class OptionUserAndGroup
  55         super OptionParameter
  56
  57         redef type VALUE: nullable UserGroup
  58
  59         #init for_droping_privileges() do init("Drop privileges to user:group or simply user", "-u", "--usergroup")
  60         init(help: String, names: String...) do init_opt(help, null, names)
  61         private init init_user_and_group(help: String, names: String...) do init_opt(help, null, names)
  62
  63         redef fun convert(str)
  64         do
  65                 var words = str.split(":")
  66                 if words.length == 1 then
  67                         return new UserGroup(str, null)
  68                 else if words.length == 2 then
  69                         return new UserGroup(words[0], words[1])
  70                 else
  71                         errors.add("Option {names.join(", ")} expected parameter in the format \"user:group\" or simply \"user\".\n")
  72                         abort # FIXME only for nitc, remove and replace with next line when FFI is working in nitg
  73                         #return null
  74                 end
  75         end
  76 end