nixos/pcscd: fix #121088

nixos/modules/services/hardware/pcscd.nix

@@ -57,6 +57,16 @@ in
     systemd.services.pcscd = {
       environment.PCSCLITE_HP_DROPDIR = pluginEnv;
       restartTriggers = [ "/etc/reader.conf" ];
+
+      # If the cfgFile is empty and not specified (in which case the default
+      # /etc/reader.conf is assumed), pcscd will happily start going through the
+      # entire confdir (/etc in our case) looking for a config file and try to
+      # parse everything it finds. Doesn't take a lot of imagination to see how
+      # well that works. It really shouldn't do that to begin with, but to work
+      # around it, we force the path to the cfgFile.
+      #
+      # https://github.com/NixOS/nixpkgs/issues/121088
+      serviceConfig.ExecStart = [ "" "${getBin pkgs.pcsclite}/bin/pcscd -f -x -c ${cfgFile}" ];
     };
   };
 }