nix flake and better run.sh

.envrc

@@ -0,0 +1 @@
+use_flake

.gitignore

@@ -7,4 +7,6 @@
 *.pcap
 
 # docship
-/output
+/output
+
+.direnv/

flake.nix

@@ -0,0 +1,54 @@
+{
+  description = "build environment";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/24.05";
+
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+
+  outputs =
+    { self
+    , nixpkgs
+    , flake-utils
+    ,
+    }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        packages = {
+          default = pkgs.stdenv.mkDerivation {
+            version = "1.0.0";
+            pname = "dev env";
+            src = ./.;
+
+            nativeBuildInputs = with pkgs.buildPackages; [
+              llvmPackages.clang-unwrapped
+              llvmPackages.bintools-unwrapped
+            ];
+
+            # first path will be computed within build env, the second one will be taken from the environment
+            installPhase = ''
+              mkdir -p $out/bin
+              { echo "export PATH=$PATH:\$PATH";
+                echo "exec \$SHELL";
+              } >> $out/bin/dev-env
+
+              chmod +x $out/bin/dev-env
+            '';
+          };
+        };
+
+        devShells.default = pkgs.mkShell {
+          nativeBuildInputs = with pkgs.buildPackages; [
+            llvmPackages.clang-unwrapped
+            llvmPackages.bintools-unwrapped
+          ];
+
+          shellHook = ''
+          '';
+        };
+      }
+    );
+}

run.sh

@@ -2,13 +2,32 @@
 set -xue
 
 QEMU=qemu-system-riscv32
-CC=/opt/homebrew/opt/llvm/bin/clang
-OBJCOPY=/opt/homebrew/opt/llvm/bin/llvm-objcopy
 
-CFLAGS="-std=c11 -O2 -g3 -Wall -Wextra --target=riscv32 -ffreestanding -nostdlib"
+if [[ -n "$IN_NIX_SHELL" ]]; then
+CC=clang
+OBJCOPY=llvm-objcopy
+else
+TOOLCHAIN="${TOOLCHAIN:-}"
+if [[ ! -f $TOOLCHAIN/clang ]]; then
+if [[ -f /run/current-system/sw/bin/clang ]]; then
+TOOLCHAIN=/run/current-system/sw/bin
+elif [[ -f /opt/homebrew/opt/llvm/bin/clang ]]; then
+TOOLCHAIN=/opt/homebrew/opt/llvm/bin/
+else
+echo "Cannot find toolchain"
+exit 1
+fi
+fi
+echo "Using toolchain at ${TOOLCHAIN}"
+CC=$TOOLCHAIN/clang
+OBJCOPY=$TOOLCHAIN/llvm-objcopy
+fi
+
+CFLAGS="-std=c11 -O2 -gdwarf-4 -g3 -Wall -Wextra --target=riscv32-unknown-elf -fno-stack-protector -ffreestanding -nostdlib"
 
 # シェルをビルド
 $CC $CFLAGS -Wl,-Tuser.ld -Wl,-Map=shell.map -o shell.elf shell.c user.c common.c
+
 $OBJCOPY --set-section-flags .bss=alloc,contents -O binary shell.elf shell.bin
 $OBJCOPY -Ibinary -Oelf32-littleriscv shell.bin shell.bin.o