Move all of NixOS to nixos/ in preparation of the repository merge

nixos/modules/services/databases/openldap.nix

@@ -0,0 +1,58 @@
+{ config, pkgs, ... }:
+
+with pkgs.lib;
+
+let
+
+  cfg = config.services.openldap;
+  openldap = pkgs.openldap;
+
+  configFile = pkgs.writeText "slapd.conf" cfg.extraConfig;
+
+in
+
+{
+
+  ###### interface
+
+  options = {
+
+    services.openldap = {
+
+      enable = mkOption {
+        default = false;
+        description = "
+          Whether to enable the ldap server.
+        ";
+      };
+
+      extraConfig = mkOption {
+        default = "";
+        description = "
+          sldapd.conf configuration
+        ";
+      };
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf config.services.openldap.enable {
+
+    environment.systemPackages = [ openldap ];
+
+    systemd.services.openldap = {
+      description = "LDAP server";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+      preStart = ''
+        mkdir -p /var/run/slapd
+      '';
+      serviceConfig.ExecStart = "${openldap}/libexec/slapd -d 0 -f ${configFile}";
+    };
+
+  };
+
+}