X-Git-Url: http://nitlanguage.org

diff --git a/lib/privileges.nit b/lib/privileges.nit
index 05f8fc7..f17a28e 100644
--- a/lib/privileges.nit
+++ b/lib/privileges.nit
@@ -22,19 +22,45 @@ module privileges
 
 import opts
 
+redef class Text
+	# Does the operating system know the user named `self`?
+	fun user_exists: Bool
+	do
+		var passwd = new Passwd.from_name(to_s)
+		return not passwd.address_is_null
+	end
+
+	# Does the operating system know the group named `self`?
+	fun group_exists: Bool
+	do
+		var passwd = new Group.from_name(to_s)
+		return not passwd.address_is_null
+	end
+end
+
+# Class to manage user groups
 class UserGroup
+
+	# User name
 	var user: String
+
+	# Group name
 	var group: nullable String
 
+	# Drop privileges of the running program to those of `self`
+	#
+	# require: `user.user_exists and (group == null or group.group_exists)`
 	fun drop_privileges
 	do
 		var passwd = new Passwd.from_name(user)
+		assert not passwd.address_is_null
 		var uid = passwd.uid
 
 		var group = group
 		var gid
 		if group != null then
 			var gpasswd = new Group.from_name(group)
+			assert not gpasswd.address_is_null
 			gid = gpasswd.gid
 		else gid = passwd.gid
 
@@ -44,21 +70,16 @@ class UserGroup
 end
 
 # Option to ask for a username and group
-class OptionDropPrivileges
-	super OptionUserAndGroup
-
-	init do init_user_and_group("Drop privileges to user:group or simply user", "-u", "--usergroup")
-end
-
-# Option to ask for a username and group
 class OptionUserAndGroup
 	super OptionParameter
 
 	redef type VALUE: nullable UserGroup
 
-	#init for_droping_privileges() do init("Drop privileges to user:group or simply user", "-u", "--usergroup")
-	init(help: String, names: String...) do init_opt(help, null, names)
-	private init init_user_and_group(help: String, names: String...) do init_opt(help, null, names)
+	# Create an `OptionUserAndGroup` for dropping privileges
+	init for_dropping_privileges
+	do
+		init("Drop privileges to user:group or simply user", null, ["-u", "--usergroup"])
+	end
 
 	redef fun convert(str)
 	do
@@ -69,8 +90,7 @@ class OptionUserAndGroup
 			return new UserGroup(words[0], words[1])
 		else
 			errors.add("Option {names.join(", ")} expected parameter in the format \"user:group\" or simply \"user\".\n")
-			abort # FIXME only for nitc, remove and replace with next line when FFI is working in nitg
-			#return null
+			return null
 		end
 	end
 end