Merge pull request #61257 from matthewbauer/add-binfmt-emulated-systems

nixos/binfmt: handle emulatedSystems

nixos/modules/rename.nix

@@ -234,6 +234,9 @@ with lib;
     (mkRenamedOptionModule [ "hardware" "ckb" "enable" ] [ "hardware" "ckb-next" "enable" ])
     (mkRenamedOptionModule [ "hardware" "ckb" "package" ] [ "hardware" "ckb-next" "package" ])
 
+    # binfmt
+    (mkRenamedOptionModule [ "boot" "binfmtMiscRegistrations" ] [ "boot" "binfmt" "registrations" ])
+
   ] ++ (flip map [ "blackboxExporter" "collectdExporter" "fritzboxExporter"
                    "jsonExporter" "minioExporter" "nginxExporter" "nodeExporter"
                    "snmpExporter" "unifiExporter" "varnishExporter" ]

nixos/modules/system/boot/binfmt.nix

@@ -1,8 +1,8 @@
-{ config, lib, ... }:
+{ config, lib, pkgs, ... }:
 let
   inherit (lib) mkOption types optionalString;
 
-  cfg = config.boot.binfmtMiscRegistrations;
+  cfg = config.boot.binfmt;
 
   makeBinfmtLine = name: { recognitionType, offset, magicOrExtension
                          , mask, preserveArgvZero, openBinary
@@ -13,25 +13,122 @@ let
     mask' = toString mask;
     interpreter = "/run/binfmt/${name}";
     flags = if !(matchCredentials -> openBinary)
-              then throw "boot.binfmtMiscRegistrations.${name}: you can't specify openBinary = false when matchCredentials = true."
+              then throw "boot.binfmt.registrations.${name}: you can't specify openBinary = false when matchCredentials = true."
             else optionalString preserveArgvZero "P" +
                  optionalString (openBinary && !matchCredentials) "O" +
                  optionalString matchCredentials "C" +
                  optionalString fixBinary "F";
   in ":${name}:${type}:${offset'}:${magicOrExtension}:${mask'}:${interpreter}:${flags}";
 
-  binfmtFile = builtins.toFile "binfmt_nixos.conf"
-    (lib.concatStringsSep "\n" (lib.mapAttrsToList makeBinfmtLine cfg));
-
   activationSnippet = name: { interpreter, ... }:
     "ln -sf ${interpreter} /run/binfmt/${name}";
-  activationScript = ''
+
-    mkdir -p -m 0755 /run/binfmt
+  getEmulator = system: (lib.systems.elaborate { inherit system; }).emulator pkgs;
-    ${lib.concatStringsSep "\n" (lib.mapAttrsToList activationSnippet cfg)}
+
-  '';
+  # Mapping of systems to “magicOrExtension” and “mask”. Mostly taken from:
+  # - https://github.com/cleverca22/nixos-configs/blob/master/qemu.nix
+  # and
+  # - https://github.com/qemu/qemu/blob/master/scripts/qemu-binfmt-conf.sh
+  # TODO: maybe put these in a JSON file?
+  magics = {
+    armv6l-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\x00\xff\xfe\xff\xff\xff'';
+    };
+    armv7l-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x28\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\x00\xff\xfe\xff\xff\xff'';
+    };
+    aarch64-linux = {
+      magicOrExtension = ''\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\x00\xff\xfe\xff\xff\xff'';
+    };
+    aarch64_be-linux = {
+      magicOrExtension = ''\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xb7'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    i386-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    i486-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    i586-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    i686-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    x86_64-linux = {
+      magicOrExtension = ''\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x3e\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    alpha-linux = {
+      magicOrExtension = ''\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x26\x90'';
+      mask = ''\xff\xff\xff\xff\xff\xfe\xfe\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    sparc64-linux = {
+      magicOrExtension = ''\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x02'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    sparc-linux = {
+      magicOrExtension = ''\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x12'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    powerpc-linux = {
+      magicOrExtension = ''\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x14'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    powerpc64-linux = {
+      magicOrExtension = ''\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x15'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    powerpc64le-linux = {
+      magicOrExtension = ''\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x15\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\x00'';
+    };
+    mips-linux = {
+      magicOrExtension = ''\x7fELF\x01\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    mipsel-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    mips64-linux = {
+      magicOrExtension = ''\x7fELF\x02\x02\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff'';
+    };
+    mips64el-linux = {
+      magicOrExtension = ''\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x08\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    riscv32-linux = {
+      magicOrExtension = ''\x7fELF\x01\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    riscv64-linux = {
+      magicOrExtension = ''\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00'';
+      mask = ''\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'';
+    };
+    x86_64-windows = {
+      magicOrExtension = ".exe";
+      recognitionType = "extension";
+    };
+    i686-windows = {
+      magicOrExtension = ".exe";
+      recognitionType = "extension";
+    };
+  };
+
 in {
   options = {
-    boot.binfmtMiscRegistrations = mkOption {
+    boot.binfmt = {
+      registrations = mkOption {
         default = {};
 
         description = ''
@@ -126,12 +223,39 @@ in {
           };
         }));
       };
+
+      emulatedSystems = mkOption {
+        default = [];
+        description = ''
+          List of systems to emulate. Will also configure Nix to
+          support your new systems.
+        '';
+        type = types.listOf types.string;
+      };
+    };
   };
 
-  config = lib.mkIf (cfg != {}) {
+  config = {
-    environment.etc."binfmt.d/nixos.conf".source = binfmtFile;
+    boot.binfmt.registrations = builtins.listToAttrs (map (system: {
-    system.activationScripts.binfmt = activationScript;
+      name = system;
-    systemd.additionalUpstreamSystemUnits =
+      value = {
+        interpreter = getEmulator system;
+      } // (magics.${system} or (throw "Cannot create binfmt registration for system ${system}"));
+    }) cfg.emulatedSystems);
+    # TODO: add a nix.extraPlatforms option to NixOS!
+    nix.extraOptions = lib.mkIf (cfg.emulatedSystems != []) ''
+      extra-platforms = ${toString (cfg.emulatedSystems ++ lib.optional pkgs.stdenv.hostPlatform.isx86_64 "i686-linux")}
+    '';
+    nix.sandboxPaths = lib.mkIf (cfg.emulatedSystems != [])
+      ([ "/run/binfmt" ] ++ (map (system: dirOf (dirOf (getEmulator system))) cfg.emulatedSystems));
+
+    environment.etc."binfmt.d/nixos.conf".source = builtins.toFile "binfmt_nixos.conf"
+      (lib.concatStringsSep "\n" (lib.mapAttrsToList makeBinfmtLine config.boot.binfmt.registrations));
+    system.activationScripts.binfmt = ''
+      mkdir -p -m 0755 /run/binfmt
+      ${lib.concatStringsSep "\n" (lib.mapAttrsToList activationSnippet config.boot.binfmt.registrations)}
+    '';
+    systemd.additionalUpstreamSystemUnits = lib.mkIf (config.boot.binfmt.registrations != {})
       [ "proc-sys-fs-binfmt_misc.automount"
         "proc-sys-fs-binfmt_misc.mount"
       ];