uboot: (firmwareOdroidC2/C4) don't invoke patch tool, use patches = [] instead

https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/setup.sh#L948
this can do it nicely.

Signed-off-by: Anton Arapov <anton@deadbeef.mx>

nixos/modules/services/network-filesystems/nfsd.nix

@@ -0,0 +1,175 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+
+  cfg = config.services.nfs.server;
+
+  exports = pkgs.writeText "exports" cfg.exports;
+
+in
+
+{
+  imports = [
+    (mkRenamedOptionModule [ "services" "nfs" "lockdPort" ] [ "services" "nfs" "server" "lockdPort" ])
+    (mkRenamedOptionModule [ "services" "nfs" "statdPort" ] [ "services" "nfs" "server" "statdPort" ])
+  ];
+
+  ###### interface
+
+  options = {
+
+    services.nfs = {
+
+      server = {
+        enable = mkOption {
+          type = types.bool;
+          default = false;
+          description = ''
+            Whether to enable the kernel's NFS server.
+          '';
+        };
+
+        extraNfsdConfig = mkOption {
+          type = types.str;
+          default = "";
+          description = ''
+            Extra configuration options for the [nfsd] section of /etc/nfs.conf.
+          '';
+        };
+
+        exports = mkOption {
+          type = types.lines;
+          default = "";
+          description = ''
+            Contents of the /etc/exports file.  See
+            <citerefentry><refentrytitle>exports</refentrytitle>
+            <manvolnum>5</manvolnum></citerefentry> for the format.
+          '';
+        };
+
+        hostName = mkOption {
+          type = types.nullOr types.str;
+          default = null;
+          description = ''
+            Hostname or address on which NFS requests will be accepted.
+            Default is all.  See the <option>-H</option> option in
+            <citerefentry><refentrytitle>nfsd</refentrytitle>
+            <manvolnum>8</manvolnum></citerefentry>.
+          '';
+        };
+
+        nproc = mkOption {
+          type = types.int;
+          default = 8;
+          description = ''
+            Number of NFS server threads.  Defaults to the recommended value of 8.
+          '';
+        };
+
+        createMountPoints = mkOption {
+          type = types.bool;
+          default = false;
+          description = "Whether to create the mount points in the exports file at startup time.";
+        };
+
+        mountdPort = mkOption {
+          type = types.nullOr types.int;
+          default = null;
+          example = 4002;
+          description = ''
+            Use fixed port for rpc.mountd, useful if server is behind firewall.
+          '';
+        };
+
+        lockdPort = mkOption {
+          type = types.nullOr types.int;
+          default = null;
+          example = 4001;
+          description = ''
+            Use a fixed port for the NFS lock manager kernel module
+            (<literal>lockd/nlockmgr</literal>).  This is useful if the
+            NFS server is behind a firewall.
+          '';
+        };
+
+        statdPort = mkOption {
+          type = types.nullOr types.int;
+          default = null;
+          example = 4000;
+          description = ''
+            Use a fixed port for <command>rpc.statd</command>. This is
+            useful if the NFS server is behind a firewall.
+          '';
+        };
+
+      };
+
+    };
+
+  };
+
+
+  ###### implementation
+
+  config = mkIf cfg.enable {
+
+    services.nfs.extraConfig = ''
+      [nfsd]
+      threads=${toString cfg.nproc}
+      ${optionalString (cfg.hostName != null) "host=${cfg.hostName}"}
+      ${cfg.extraNfsdConfig}
+
+      [mountd]
+      ${optionalString (cfg.mountdPort != null) "port=${toString cfg.mountdPort}"}
+
+      [statd]
+      ${optionalString (cfg.statdPort != null) "port=${toString cfg.statdPort}"}
+
+      [lockd]
+      ${optionalString (cfg.lockdPort != null) ''
+        port=${toString cfg.lockdPort}
+        udp-port=${toString cfg.lockdPort}
+      ''}
+    '';
+
+    services.rpcbind.enable = true;
+
+    boot.supportedFilesystems = [ "nfs" ]; # needed for statd and idmapd
+
+    environment.etc.exports.source = exports;
+
+    systemd.services.nfs-server =
+      { enable = true;
+        wantedBy = [ "multi-user.target" ];
+
+        preStart =
+          ''
+            mkdir -p /var/lib/nfs/v4recovery
+          '';
+      };
+
+    systemd.services.nfs-mountd =
+      { enable = true;
+        restartTriggers = [ exports ];
+
+        preStart =
+          ''
+            mkdir -p /var/lib/nfs
+
+            ${optionalString cfg.createMountPoints
+              ''
+                # create export directories:
+                # skip comments, take first col which may either be a quoted
+                # "foo bar" or just foo (-> man export)
+                sed '/^#.*/d;s/^"\([^"]*\)".*/\1/;t;s/[ ].*//' ${exports} \
+                | xargs -d '\n' mkdir -p
+              ''
+            }
+          '';
+      };
+
+  };
+
+}