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/virtualisation/amazon-init.nix

@@ -0,0 +1,87 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.virtualisation.amazon-init;
+
+  script = ''
+    #!${pkgs.runtimeShell} -eu
+
+    echo "attempting to fetch configuration from EC2 user data..."
+
+    export HOME=/root
+    export PATH=${pkgs.lib.makeBinPath [ config.nix.package config.systemd.package pkgs.gnugrep pkgs.git pkgs.gnutar pkgs.gzip pkgs.gnused pkgs.xz config.system.build.nixos-rebuild]}:$PATH
+    export NIX_PATH=nixpkgs=/nix/var/nix/profiles/per-user/root/channels/nixos:nixos-config=/etc/nixos/configuration.nix:/nix/var/nix/profiles/per-user/root/channels
+
+    userData=/etc/ec2-metadata/user-data
+
+    # Check if user-data looks like a shell script and execute it with the
+    # runtime shell if it does. Otherwise treat it as a nixos configuration
+    # expression
+    if IFS= LC_ALL=C read -rN2 shebang < $userData && [ "$shebang" = '#!' ]; then
+      # NB: we cannot chmod the $userData file, this is why we execute it via
+      # `pkgs.runtimeShell`. This means we have only limited support for shell
+      # scripts compatible with the `pkgs.runtimeShell`.
+      exec ${pkgs.runtimeShell} $userData
+    fi
+
+    if [ -s "$userData" ]; then
+      # If the user-data looks like it could be a nix expression,
+      # copy it over. Also, look for a magic three-hash comment and set
+      # that as the channel.
+      if sed '/^\(#\|SSH_HOST_.*\)/d' < "$userData" | grep -q '\S'; then
+        channels="$(grep '^###' "$userData" | sed 's|###\s*||')"
+        while IFS= read -r channel; do
+          echo "writing channel: $channel"
+        done < <(printf "%s\n" "$channels")
+
+        if [[ -n "$channels" ]]; then
+          printf "%s" "$channels" > /root/.nix-channels
+          nix-channel --update
+        fi
+
+        echo "setting configuration from EC2 user data"
+        cp "$userData" /etc/nixos/configuration.nix
+      else
+        echo "user data does not appear to be a Nix expression; ignoring"
+        exit
+      fi
+    else
+      echo "no user data is available"
+      exit
+    fi
+
+    nixos-rebuild switch
+  '';
+in {
+
+  options.virtualisation.amazon-init = {
+    enable = mkOption {
+      default = true;
+      type = types.bool;
+      description = ''
+        Enable or disable the amazon-init service.
+      '';
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.amazon-init = {
+      inherit script;
+      description = "Reconfigure the system from EC2 userdata on startup";
+
+      wantedBy = [ "multi-user.target" ];
+      after = [ "multi-user.target" ];
+      requires = [ "network-online.target" ];
+
+      restartIfChanged = false;
+      unitConfig.X-StopOnRemoval = false;
+
+      serviceConfig = {
+        Type = "oneshot";
+        RemainAfterExit = true;
+      };
+    };
+  };
+}