Added guestUsers job for automatical adding guests

svn path=/nixos/trunk/; revision=13732

system/options.nix

@@ -3065,5 +3065,6 @@ root        ALL=(ALL) SETENV: ALL
     (import ../upstart-jobs/cron/locate.nix)
     (import ../upstart-jobs/manual.nix)
     (import ../upstart-jobs/rogue.nix)
+    (import ../upstart-jobs/guest-users.nix)
   ];
 }

upstart-jobs/guest-users.nix

@@ -0,0 +1,76 @@
+{pkgs, config}: 
+let
+  inherit(pkgs.lib) mkOption;
+
+  options = {
+    services = {
+      guestUsers = {
+        enable = mkOption {
+	  default = false;
+	  description = "
+	    Whether to enable automatic addition of users with empty passwords
+	  ";
+	};
+	users = mkOption {
+	  default = ["guest"];
+	  description = "
+	    List of usernames to add
+	  ";
+	};
+	includeRoot = mkOption {
+	  default = false;
+	  description = "
+	    LEAVE THAT ALONE; whether to reset root password
+	  ";
+	};
+	extraGroups = mkOption {
+	  default = ["audio"];
+	  description = "
+	    Extra groups to grant
+	  ";
+	};
+      };
+    };
+  };
+  inherit (pkgs.lib) concatStringsSep optional optionalString;
+
+  inherit (config.services.guestUsers) enable users includeRoot extraGroups;
+
+  userEntry = user:
+  {
+    name = user;
+    description = "NixOS guest user";
+    home = "/home/${user}";
+    createHome = true;
+    group = "users";
+    extraGroups = extraGroups;
+    shell = "/bin/sh";
+  };
+
+  nameString = (concatStringsSep " " users) + optionalString includeRoot " root";
+
+in 
+
+{
+  require = options;
+  services = {
+    extraJobs = optional enable {
+      name = "clear-passwords";
+      job = ''
+        description "Clear guest passwords"
+	start on startup
+	script
+	  for i in ${nameString}; do
+	      echo | ${pkgs.pwdutils}/bin/passwd --stdin $i
+	  done
+	end script
+      '';
+    };
+    mingetty = {
+      helpLine = optionalString enable "\nThis users have empty passwords: ${nameString}";
+    };
+  };
+  users = {
+    extraUsers = map userEntry users;
+  };
+}