add build-host tftp server

pkgs/tufted/default.nix

@@ -0,0 +1,44 @@
+{
+  lua5_3
+, stdenv
+, fennel
+, fetchFromGitHub
+, makeWrapper
+} :
+let
+  tufty-lua = lua.pkgs.buildLuaPackage {
+    pname = "tufty";
+    version = "1";
+    src = fetchFromGitHub {
+      owner = "telent";
+      repo = "tufty";
+      sha256 = "sha256-m5UEfcCNdG0Ku380cPhu1inNQmSfQJ5NcRIxLohUOh8=";
+      rev = "75c6d38713a82f4197f91dcb182a2e34f255bf7c";
+    };
+    buildPhase = ":";
+    installPhase = ''
+        mkdir -p "$out/share/lua/${lua5_3.luaversion}"
+        cp src/*.lua "$out/share/lua/${lua5_3.luaversion}/"
+      '';
+  };
+  lua = lua5_3.withPackages (ps: with ps; [
+    tufty-lua luasocket luaposix
+  ]);
+  fennel_ = (fennel.override { inherit lua; });
+in stdenv.mkDerivation {
+  pname = "tufted";
+  version = "1";
+  phases =  [ "unpackPhase" "installPhase" ];
+  buildInputs = [ lua fennel_ ];
+  nativeBuildInputs = [ makeWrapper ];
+  src = ./.;
+  installPhase = ''
+    mkdir -p $out/lib
+    cp tufted.fnl $out/lib
+    makeWrapper ${fennel_}/bin/fennel \
+      $out/bin/tufted \
+      --add-flags "--add-fennel-path $out/lib/?.fnl" \
+      --add-flags "--add-package-path $out/lib/?.lua" \
+      --add-flags "$out/lib/tufted.fnl"
+  '';
+}

pkgs/tufted/tufted.fnl

@@ -0,0 +1,51 @@
+(local tftp (require :tftp))
+(local { : realpath} (require :posix.stdlib))
+(local { : view } (require :fennel))
+
+(local options
+       (match arg
+         ["-a" ip-address dir]
+         { :allow ip-address :base-directory (realpath dir)}
+
+         [dir]
+         { :allow nil :base-directory (realpath dir)}
+
+         []
+         (error "missing command line parameters")
+         ))
+
+(print (.. "TFTP serving from " options.base-directory))
+
+(fn merge-pathname [directory filename]
+  (if (directory:match "/$")
+      (.. directory  filename)
+      (.. directory "/" filename)))
+
+(->
+ (tftp:listen
+  (fn [file host port]
+    (if (or (not options.allow) (= host options.allow))
+        (let [pathname (merge-pathname options.base-directory file)
+              f (io.open pathname "rb")
+              size (f:seek "end")]
+          (f:seek "set" 0)
+          (var eof? false)
+          (values
+           (fn handler [reqlen]
+             (let [bytes (f:read reqlen)]
+               (if eof?
+                   false
+                   bytes
+                   (values true bytes)
+                   (do
+                     ;; if the file length is divisible by the block
+                     ;; length, need to send an empty block at eof
+                     (set eof? true)
+                     (values true "")))))
+           size))
+        (error "host not allowed")))
+  nil
+  ["*"]
+  69)
+
+(os.exit))