add clash-updater

pkgs/network/proxy/clash-premium/default.nix

@@ -49,6 +49,20 @@ stdenv.mkDerivation {
         fi
     '';
 
+    makeUpdater = { subscription, name }: stdenv.mkDerivation {
+        name = "clash-updater-${name}";
+        src = ./updater.sh;
+
+        dontConfigure = true;
+        dontBuild = true;
+        dontPatchELF = true;
+        dontUnpack = true;
+
+        installPhase = ''
+            makeWrapper $src $out/bin/clash-updater-${name} --set SUBSCRIPTION_URL "${subscription}"
+        '';
+    };
+
     meta = {
         description = "close-sourced pre-built Clash binary with TUN support and more";
         homepage = "https://github.com/Dreamacro/clash/releases/premium";
@@ -60,3 +74,4 @@ stdenv.mkDerivation {
         ];
     };
 }
+

pkgs/network/proxy/clash-premium/updater.sh

@@ -0,0 +1,8 @@
+#!/bin/bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+env
+
+sleep 10000