permit debug information through gdb

Author: mazunki

deps/musl/default.nix

@@ -2,6 +2,7 @@
 stdenv
 , pkgs
 , linuxHeaders ? null
+, debug ? false
 }:
 stdenv.mkDerivation rec {
   pname = "musl-includeos";
@@ -40,7 +41,8 @@ stdenv.mkDerivation rec {
     ./configure --prefix=$out --disable-shared --enable-debug --with-malloc=oldmalloc CROSS_COMPILE=${stdenv.targetPlatform.config}-
   '';
 
-  CFLAGS = "-Wno-error=int-conversion -nostdinc";
+  dontStrip = debug;
+  CFLAGS = "-Wno-error=int-conversion -nostdinc${pkgs.lib.optionalString debug " -g"}";
 
   meta = {
     description = "musl - Linux based libc, built with IncludeOS linux-like syscalls";

flake.lock

@@ -3,18 +3,19 @@
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/25.05";
-    vmrunner.url = "github:includeos/vmrunner";
+    # vmrunner.url = "github:includeos/vmrunner";
+    vmrunner.url = "github:mazunki/vmrunner";
   };
 
   outputs = { self, nixpkgs, vmrunner }:
     let
       system = "x86_64-linux";
 
-      mkIncludeos = { withCcache ? false, smp ? false }:
+      mkIncludeos = { withCcache ? false, smp ? false, debug ? false }:
         let
           overlays = [
             (import ./overlay.nix {
-              inherit withCcache smp;
+              inherit withCcache smp debug;
               disableTargetWarning = true;
             })
           ];
@@ -45,61 +46,68 @@
           inherit chainloader;      # 32-bit boot stub that hotswaps into the 64-bit unikernel
         };
 
-      default = mkIncludeos {};
-      mkUnikernel = import ./mkUnikernel.nix { inherit system default vmrunner; };
+      default      = mkIncludeos {};
+      defaultDebug = mkIncludeos { debug = true; };
+      mkUnikernel  = import ./mkUnikernel.nix { inherit system default defaultDebug vmrunner; };
     in {
       packages.${system} = {
-        default     = default.includeos;
+        default     = default.includeos // { debug = defaultDebug.includeos; };
         chainloader = default.chainloader;
         example     = mkUnikernel { unikernel = ./example; };
       };
 
       devShells.${system}.default = import ./develop.nix { includeos = default.includeos; };
 
-      lib.${system} = { inherit mkIncludeos mkUnikernel; };
+      lib.${system} = {
+        inherit mkIncludeos mkUnikernel;
 
-      apps.${system} = {
-        default = self.apps.${system}.boot-unikernel;
+        mkChainloader = { mem }:
+          vmrunner.lib.${system}.mkBoot default.chainloader { inherit mem; };
 
-        boot = {
-          type = "app";
-          program = "${vmrunner.lib.${system}.mkBoot default.chainloader {}}/bin/boot";
-        };
+        boot = { kernel ? "service", mem, kvm ? false, debug ? false }:
+          let
+            chainloaders = self.lib.${system}.mkChainloader { inherit mem; };
+            chainloader = if kvm then chainloaders.kvm
+                         else if debug then chainloaders.debug
+                         else chainloaders.default;
+          in {
+            type = "app";
+            program = "${default.pkgs.writeShellScript "boot-unikernel" ''
+              set -e
+              dir="''${1:-./result}"
+              ${default.pkgs.lib.optionalString debug ''echo "boot: $dir/${kernel}" >&2''}
+              exec ${chainloader}/bin/boot "$dir/${kernel}" "$@"
+            ''}";
+          };
 
-        boot-unikernel = {
-          type = "app";
-          program = "${default.pkgs.writeShellScript "boot-unikernel" ''
-            set -e
-            dir="''${1:-./result}"
-            shift || true
-            exec ${vmrunner.lib.${system}.mkBoot default.chainloader {}}/bin/boot \
-              -j $dir/vm.json \
-              $dir/*.elf.bin \
-              "$@"
-          ''}";
-        };
+        mkBoot1 = { src, kernel ? "service", kvm ? false, mem ? "16G", debug ? false }:
+          let
+            bootApp = self.lib.${system}.boot { inherit kernel kvm debug mem; };
+          in {
+            type = "app";
+            program = "${default.pkgs.writeShellScript "run-flake-package" ''
+              set -e
+              exec ${bootApp.program} ${src} "$@"
+            ''}";
+          };
 
-        boot-unikernel-kvm = {
-          type = "app";
-          program = "${default.pkgs.writeShellScript "boot-unikernel-kvm" ''
-            set -e
-            dir="''${1:-./result}"
-            shift || true
-            exec ${vmrunner.lib.${system}.mkBoot default.chainloader { kvm = true; }}/bin/boot \
-              -j $dir/vm.json \
-              $dir/*.elf.bin \
-              "$@"
-          ''}";
-        };
+        mkBoot = args:
+        let
+          debugSrc = args.debugSrc or args.src;
+          base     = builtins.removeAttrs args [ "debugSrc" ];
+          tcg   = self.lib.${system}.mkBoot1 (base // { kvm = false; debug = false; });
+          kvm   = self.lib.${system}.mkBoot1 (base // { kvm = true;  debug = false; });
+          debug = self.lib.${system}.mkBoot1 (base // { src = debugSrc; kvm = false; debug = true; });
+        in
+          tcg // { inherit tcg kvm debug; };
+      };
 
-        example = {
-          type = "app";
-          program = "${default.pkgs.writeShellScript "run-example" ''
-            set -e
-            built=$(nix build path:${self.outPath}#example --no-link --print-out-paths)
-            exec ${self.apps.${system}.boot-unikernel.program} $built "$@"
-          ''}";
-        };
+      apps.${system} = {
+        default = self.apps.${system}.boot-unikernel;
+
+        boot-unikernel = self.lib.${system}.boot { mem = "128m"; };
+
+        example = self.lib.${system}.mkBoot { src = self.packages.${system}.example; kernel = "hello_includeos.elf.bin"; };
       };
     };
 }

flake.nix

@@ -1,8 +1,11 @@
 # mkUnikernel.nix
-{ system, default, vmrunner }:
+{ system, default, defaultDebug, vmrunner }:
 args:
 let
-  ios           = if args ? includeos then args.includeos else default;
+  debug         = args.debug or false;
+  ios           = if args ? includeos then args.includeos
+                  else if debug then defaultDebug
+                  else default;
   vmrunnerPkg   = if args ? vmrunner then args.vmrunner
                   else vmrunner.packages.${system}.default;
 
@@ -37,6 +40,10 @@ ios.includeos.stdenv.mkDerivation {
     "-DINCLUDEOS_PACKAGE=${ios.includeos}"
     "-DCMAKE_MODULE_PATH=${ios.includeos}/cmake"
     "-DFOR_PRODUCTION=${if forProduction then "ON" else "OFF"}"
+    "-DCMAKE_BUILD_TYPE=${if debug then "Debug" else "Release"}"
+  ] ++ ios.pkgs.lib.optionals debug [
+    "-DCMAKE_C_FLAGS=-ffile-prefix-map=/build/${builtins.baseNameOf src}=/build/unikernel"
+    "-DCMAKE_CXX_FLAGS=-ffile-prefix-map=/build/${builtins.baseNameOf src}=/build/unikernel"
   ];
 
   installPhase = ''

mkUnikernel.nix

@@ -2,6 +2,7 @@
   withCcache, # Enable ccache. Requires correct permissions, see below.
   disableTargetWarning ? true, # TODO: see https://github.com/NixOS/nixpkgs/issues/395191
   smp,      # Enable multicore support (SMP)
+  debug ? false,
 } :
 final: prev: {
 
@@ -13,7 +14,7 @@ final: prev: {
     musl-unpatched = self.callPackage ./deps/musl-unpatched/default.nix { linuxHeaders = prev.linuxHeaders; };
 
     # Import IncludeOS musl which will be built and linked with IncludeOS services
-    musl-includeos = self.callPackage ./deps/musl/default.nix { };
+    musl-includeos = self.callPackage ./deps/musl/default.nix { inherit debug; };
 
     # Clang with unpatched musl for building libcxx
     clang_musl_unpatched_nolibcxx = self.llvmPkgs.clangNoLibcxx.override (old: {
@@ -191,7 +192,10 @@ final: prev: {
 
       smpFlags = if smp then [ "-DSMP=ON" ] else [];
 
-      cmakeFlags = archFlags ++ smpFlags;
+      debugFlags = if debug then [ "-DCMAKE_BUILD_TYPE=Debug" ] else [];
+      dontStrip  = debug;
+
+      cmakeFlags = archFlags ++ smpFlags ++ debugFlags;
 
       # Add some pasthroughs, for easily building the dependencies (for debugging):
       # $ nix-build -A NAME