From 95cf4c4270262249ad4d2f2ad8d1fe82ca27979d Mon Sep 17 00:00:00 2001
From: Pim Kunis <pim@kunis.nl>
Date: Wed, 25 Dec 2024 11:56:27 +0100
Subject: [PATCH] Create helper to build the ebpf programs

---
 dropworld/default.nix             | 16 ----------------
 dropworld/{dropworld.c => main.c} |  0
 flake.nix                         | 18 +++++++++++++++---
 tcpfilter/default.nix             | 16 ----------------
 tcpfilter/{tcpfilter.c => main.c} |  0
 5 files changed, 15 insertions(+), 35 deletions(-)
 delete mode 100644 dropworld/default.nix
 rename dropworld/{dropworld.c => main.c} (100%)
 delete mode 100644 tcpfilter/default.nix
 rename tcpfilter/{tcpfilter.c => main.c} (100%)

diff --git a/dropworld/default.nix b/dropworld/default.nix
deleted file mode 100644
index f102fcc..0000000
--- a/dropworld/default.nix
+++ /dev/null
@@ -1,16 +0,0 @@
-{clangStdenv, libbpf, ...}: clangStdenv.mkDerivation {
-  name = "dropworld";
-  src = ./.;
-  hardeningDisable = [ "stackprotector" "zerocallusedregs" ];
-  dontFixup = true;
-  buildInputs = [ libbpf ];
-
-  buildPhase = ''
-    clang -O2 -target bpf -g -c dropworld.c -o dropworld.o
-  '';
-
-  installPhase = ''
-    mkdir $out
-    cp dropworld.o $out
-  '';
-}
diff --git a/dropworld/dropworld.c b/dropworld/main.c
similarity index 100%
rename from dropworld/dropworld.c
rename to dropworld/main.c
diff --git a/flake.nix b/flake.nix
index 3ad43a4..3b287aa 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,5 +1,5 @@
 {
-  description = "A very basic flake";
+  description = "eBPF sandbox";
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
@@ -9,11 +9,23 @@
   outputs = inputs: inputs.flake-utils.lib.eachDefaultSystem (system:
     let
       pkgs = inputs.nixpkgs.legacyPackages.${system};
+
+      mkEbpfProg = name: src: pkgs.clangStdenv.mkDerivation {
+        name = "ebpf-${name}";
+        inherit src;
+        hardeningDisable = [ "stackprotector" "zerocallusedregs" ];
+        dontFixup = true;
+        buildInputs = with pkgs; [ libbpf ];
+
+        buildPhase = ''
+          clang -O2 -target bpf -g -c ${src}/main.c -o $out
+        '';
+      };
     in
     {
       packages = {
-        dropworld = pkgs.callPackage ./dropworld {};
-        tcpfilter = pkgs.callPackage ./tcpfilter {};
+        dropworld = mkEbpfProg "dropworld" ./dropworld;
+        tcpfilter = mkEbpfProg "tcpfilter" ./tcpfilter;
       };
 
       devShells.default = pkgs.mkShell {
diff --git a/tcpfilter/default.nix b/tcpfilter/default.nix
deleted file mode 100644
index 93140ea..0000000
--- a/tcpfilter/default.nix
+++ /dev/null
@@ -1,16 +0,0 @@
-{clangStdenv, libbpf, ...}: clangStdenv.mkDerivation {
-  name = "tcpfilter";
-  src = ./.;
-  hardeningDisable = [ "stackprotector" "zerocallusedregs" ];
-  dontFixup = true;
-  buildInputs = [ libbpf ];
-
-  buildPhase = ''
-    clang -O2 -target bpf -g -c tcpfilter.c -o tcpfilter.o
-  '';
-
-  installPhase = ''
-    mkdir $out
-    cp tcpfilter.o $out
-  '';
-}
diff --git a/tcpfilter/tcpfilter.c b/tcpfilter/main.c
similarity index 100%
rename from tcpfilter/tcpfilter.c
rename to tcpfilter/main.c