pcscd: allow multiple readerConfig entries

nixos/modules/services/hardware/pcscd.nix

@@ -1,11 +1,16 @@
-{ config, lib, pkgs, ... }:
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
 let
   cfg = config.services.pcscd;
-  cfgFile = pkgs.writeText "reader.conf" config.services.pcscd.readerConfig;
+  cfgFile = pkgs.writeText "reader.conf" (
+    builtins.concatStringsSep "\n\n" config.services.pcscd.readerConfigs
+  );
 
-  package = if config.security.polkit.enable
+  package = if config.security.polkit.enable then pkgs.pcscliteWithPolkit else pkgs.pcsclite;
-              then pkgs.pcscliteWithPolkit
-              else pkgs.pcsclite;
 
   pluginEnv = pkgs.buildEnv {
     name = "pcscd-plugins";
@@ -14,6 +19,20 @@ let
 
 in
 {
+  imports = [
+    (lib.mkChangedOptionModule
+      [ "services" "pcscd" "readerConfig" ]
+      [ "services" "pcscd" "readerConfigs" ]
+      (
+        config:
+        let
+          readerConfig = lib.getAttrFromPath [ "services" "pcscd" "readerConfig" ] config;
+        in
+        [ readerConfig ]
+      )
+    )
+  ];
+
   options.services.pcscd = {
     enable = lib.mkEnableOption "PCSC-Lite daemon, to access smart cards using SCard API (PC/SC)";
 
@@ -24,15 +43,17 @@ in
       description = "Plugin packages to be used for PCSC-Lite.";
     };
 
-    readerConfig = lib.mkOption {
+    readerConfigs = lib.mkOption {
-      type = lib.types.lines;
+      type = lib.types.listOf lib.types.lines;
-      default = "";
+      default = [ ];
-      example = ''
+      example = [
+        ''
           FRIENDLYNAME      "Some serial reader"
           DEVICENAME        /dev/ttyS0
           LIBPATH           /path/to/serial_reader.so
           CHANNELID         1
-      '';
+        ''
+      ];
       description = ''
         Configuration for devices that aren't hotpluggable.
 
@@ -68,7 +89,10 @@ in
       # around it, we force the path to the cfgFile.
       #
       # https://github.com/NixOS/nixpkgs/issues/121088
-      serviceConfig.ExecStart = [ "" "${lib.getExe package} -f -x -c ${cfgFile} ${lib.escapeShellArgs cfg.extraArgs}" ];
+      serviceConfig.ExecStart = [
+        ""
+        "${lib.getExe package} -f -x -c ${cfgFile} ${lib.escapeShellArgs cfg.extraArgs}"
+      ];
     };
   };
 }