Revert "nixos/grub: generate BLS entries"

nixos/doc/manual/release-notes/rl-2505.section.md

···
 
 - `services.gitea` now supports CAPTCHA usage through the `services.gitea.captcha` variable.
 
-- The GRUB bootloader (`boot.loader.grub`) now generates [boot loader entries](https://uapi-group.org/specifications/specs/boot_loader_specification/).
-  These files are used by userspace tools (for example, `bootctl`) to inspect the bootloader status, getting the default boot entry, the path of the kernel binary, etc.
-  As a consequence, `systemctl kexec` now works automatically: specifying the kernel and its arguments with `kexec --load` is no longer required.
-
 - `bind.cacheNetworks` now only controls access for recursive queries, where it previously controlled access for all queries.
 
 - [`services.mongodb.enableAuth`](#opt-services.mongodb.enableAuth) now uses the newer [mongosh](https://github.com/mongodb-js/mongosh) shell instead of the legacy shell to configure the initial superuser. You can configure the mongosh package to use through the [`services.mongodb.mongoshPackage`](#opt-services.mongodb.mongoshPackage) option.

nixos/modules/system/boot/loader/grub/grub.nix

···
     then realGrub.override { efiSupport = cfg.efiSupport; }
     else null;
 
-  bootPath = if cfg.mirroredBoots != [ ]
-    then (builtins.head cfg.mirroredBoots).path
-    else "/boot";
-
   f = x: optionalString (x != null) ("" + x);
 
   grubConfig = args:
···
       system.boot.loader.id = "grub";
 
       environment.systemPackages = mkIf (grub != null) [ grub ];
-
-      # Link /boot under /run/boot-loder-entries to make
-      # systemd happy even on non-EFI system
-      systemd.mounts = lib.optional (!cfg.efiSupport) {
-        what  = bootPath;
-        where = "/run/boot-loader-entries";
-        type  = "none";
-        options = "bind";
-        requiredBy = [ "local-fs.target" ];
-      };
 
       boot.loader.grub.extraPrepareConfig =
         concatStrings (mapAttrsToList (n: v: ''

nixos/modules/system/boot/loader/grub/install-grub.pl

···
 
 print STDERR "updating GRUB 2 menu...\n";
 
-# Make GRUB directory
-make_path("$bootPath/grub", { mode => 0700 });
-
-# Make BLS entries directory, see addBLSEntry
-make_path("$bootPath/loader/entries", { mode => 0700 });
-writeFile("$bootPath/loader/entries.srel", "type1");
-
-# and a temporary one for new entries
-make_path("$bootPath/loader/entries.tmp", { mode => 0700 });
+make_path("$bootPath/grub", {  mode => 0700 });
 
 # Discover whether the bootPath is on the same filesystem as / and
 # /nix/store.  If not, then all kernels and initrds must be copied to
···
 }
 
 sub addEntry {
-    # Creates a Grub menu entry for a given system
     my ($name, $path, $options, $current) = @_;
     return unless -e "$path/kernel" && -e "$path/initrd";
 
···
     $conf .= "}\n\n";
 }
 
-sub addBLSEntry {
-    # Creates a Boot Loader Specification[1] entry for a given system.
-    # The information contained in the entry mirrors a boot entry in GRUB menu.
-    #
-    # [1]: https://uapi-group.org/specifications/specs/boot_loader_specification
-    my ($prof, $spec, $gen, $link) = @_;
-
-    # collect data from system
-    my %bootspec = %{decode_json(readFile("$link/boot.json"))->{"org.nixos.bootspec.v1"}};
-    my $date = strftime("%F", localtime(lstat($link)->mtime));
-    my $kernel = $bootspec{kernel} =~ s@$storePath/@@r =~ s@/@-@r;
-    my $initrd = $bootspec{initrd} =~ s@$storePath/@@r =~ s@/@-@r;
-    my $kernelParams = readFile("$link/kernel-params");
-    my $machineId = readFile("/etc/machine-id");
-
-    if ($grubEfi eq "" && !$copyKernels) {
-        # workaround for https://github.com/systemd/systemd/issues/35729
-        make_path("$bootPath/kernels", { mode => 0755 });
-        symlink($bootspec{kernel}, "$bootPath/kernels/$kernel");
-        symlink($bootspec{initrd}, "$bootPath/kernels/$initrd");
-        $copied{"$bootPath/kernels/$kernel"} = 1;
-        $copied{"$bootPath/kernels/$initrd"} = 1;
-    }
-
-    # fill in the entry
-    my $extras = join(' ', $prof = $prof ne "system" ? " [$prof] " : "",
-                           $spec = $spec ne "" ? " ($spec) " : "");
-    my $entry = <<~END;
-      title @distroName@$extras
-      sort-key nixos
-      version Generation $gen $bootspec{label}, built on $date
-      linux kernels/$kernel
-      initrd kernels/$initrd
-      options init=$bootspec{init} $kernelParams
-      END
-    $entry .= "machine-id $machineId" if defined $machineId;
-
-    # entry file basename
-    my $name = join("-", grep { length $_ > 0 }
-        "nixos", $prof ne "system" ? $prof : "",
-        "generation", $gen,
-         $spec ? "specialisation-$spec" : "");
-
-    # write entry to the temp directory
-    writeFile("$bootPath/loader/entries.tmp/$name.conf", $entry);
-
-    # mark the default entry
-    if (readlink($link) eq $defaultConfig) {
-        writeFile("$bootPath/loader/loader.conf", "default $name.conf");
-    }
-}
-
 sub addGeneration {
     my ($name, $nameSuffix, $path, $options, $current) = @_;
 
···
             warn "skipping corrupt system profile entry ‘$link’\n";
             next;
         }
-        my $gen = nrFromGen($link);
         my $date = strftime("%F", localtime(lstat($link)->mtime));
         my $version =
             -e "$link/nixos-version"
             ? readFile("$link/nixos-version")
             : basename((glob(dirname(Cwd::abs_path("$link/kernel")) . "/lib/modules/*"))[0]);
-        addGeneration("@distroName@ - Configuration " . $gen, " ($date - $version)", $link, $subEntryOptions, 0);
-
-        addBLSEntry(basename($profile), "", $gen, $link);
-        foreach my $spec (glob "$link/specialisation/*") {
-            addBLSEntry(basename($profile), $spec, $gen, $spec);
-        }
+        addGeneration("@distroName@ - Configuration " . nrFromGen($link), " ($date - $version)", $link, $subEntryOptions, 0);
     }
 
     $conf .= "}\n";
···
     next unless $name =~ /^\w+$/;
     addProfile $profile, "@distroName@ - Profile '$name'";
 }
-
-# Atomically replace the BLS entries directory
-my $entriesDir = "$bootPath/loader/entries";
-rename $entriesDir, "$entriesDir.bak" or die "cannot rename $entriesDir to $entriesDir.bak: $!\n";
-rename "$entriesDir.tmp", $entriesDir or die "cannot rename $entriesDir.tmp to $entriesDir: $!\n";
-rmtree "$entriesDir.bak" or die "cannot remove $entriesDir.bak: $!\n";
 
 # extraPrepareConfig could refer to @bootPath@, which we have to substitute
 $extraPrepareConfig =~ s/\@bootPath\@/$bootPath/g;

nixos/tests/all-tests.nix

···
   greetd-no-shadow = handleTest ./greetd-no-shadow.nix {};
   grocy = handleTest ./grocy.nix {};
   grow-partition = runTest ./grow-partition.nix;
-  grub = import ./grub.nix { inherit pkgs runTest; };
+  grub = handleTest ./grub.nix {};
   guacamole-server = handleTest ./guacamole-server.nix {};
   guix = handleTest ./guix {};
   gvisor = handleTest ./gvisor.nix {};

nixos/tests/grub.nix

···
-{ pkgs, runTest }:
-
-{
-  # Basic GRUB setup with BIOS and a password
-  basic = runTest {
-    name = "grub-basic";
-    meta.maintainers = with pkgs.lib.maintainers; [ rnhmjoj ];
-
-    nodes.machine = { ... }: {
-      virtualisation.useBootLoader = true;
-      boot.loader.timeout = null;
-      boot.loader.grub = {
-        enable = true;
-        users.alice.password = "supersecret";
-        # OCR is not accurate enough
-        extraConfig = "serial; terminal_output serial";
-      };
-    };
-
-    testScript = ''
-      def grub_login_as(user, password):
-          """
-          Enters user and password to log into GRUB
-          """
-          machine.wait_for_console_text("Enter username:")
-          machine.send_chars(user + "\n")
-          machine.wait_for_console_text("Enter password:")
-          machine.send_chars(password + "\n")
-
-
-      def grub_select_all_configurations():
-          """
-          Selects "All configurations" from the GRUB menu
-          to trigger a login request.
-          """
-          machine.send_monitor_command("sendkey down")
-          machine.send_monitor_command("sendkey ret")
-
-
-      machine.start()
+import ./make-test-python.nix ({ lib, ... }: {
+  name = "grub";
 
-      # wait for grub screen
-      machine.wait_for_console_text("GNU GRUB")
+  meta = with lib.maintainers; {
+    maintainers = [ rnhmjoj ];
+  };
 
-      grub_select_all_configurations()
-      with subtest("Invalid credentials are rejected"):
-          grub_login_as("wronguser", "wrongsecret")
-          machine.wait_for_console_text("error: access denied.")
+  nodes.machine = { ... }: {
+    virtualisation.useBootLoader = true;
 
-      grub_select_all_configurations()
-      with subtest("Valid credentials are accepted"):
-          grub_login_as("alice", "supersecret")
-          machine.send_chars("\n")  # press enter to boot
-          machine.wait_for_console_text("Linux version")
+    boot.loader.timeout = null;
+    boot.loader.grub = {
+      enable = true;
+      users.alice.password = "supersecret";
 
-      with subtest("Machine boots correctly"):
-          machine.wait_for_unit("multi-user.target")
-    '';
+      # OCR is not accurate enough
+      extraConfig = "serial; terminal_output serial";
     };
+  };
 
-  # Test boot loader entries on EFI
-  bls-efi = runTest {
-    name = "grub-bls-efi";
-    meta.maintainers = with pkgs.lib.maintainers; [ rnhmjoj ];
+  testScript = ''
+    def grub_login_as(user, password):
+        """
+        Enters user and password to log into GRUB
+        """
+        machine.wait_for_console_text("Enter username:")
+        machine.send_chars(user + "\n")
+        machine.wait_for_console_text("Enter password:")
+        machine.send_chars(password + "\n")
 
-    nodes.machine = { pkgs, ... }: {
-      virtualisation.useBootLoader = true;
-      virtualisation.useEFIBoot = true;
-      boot.loader.efi.canTouchEfiVariables = true;
-      boot.loader.grub.enable = true;
-      boot.loader.grub.efiSupport = true;
-    };
 
-    testScript = ''
-      with subtest("Machine boots correctly"):
-          machine.wait_for_unit("multi-user.target")
+    def grub_select_all_configurations():
+        """
+        Selects "All configurations" from the GRUB menu
+        to trigger a login request.
+        """
+        machine.send_monitor_command("sendkey down")
+        machine.send_monitor_command("sendkey ret")
 
-      with subtest("Boot entries are installed"):
-          entries = machine.succeed("bootctl list")
-          print(entries)
-          error = "NixOS boot entry not found in bootctl list."
-          assert "version: Generation 1" in entries, error
 
-      with subtest("systemctl kexec can detect the kernel"):
-          machine.succeed("systemctl kexec --dry-run")
+    machine.start()
 
-      with subtest("systemctl kexec really works"):
-          machine.execute("systemctl kexec", check_return=False)
-          machine.connected = False
-          machine.connect()
-          machine.wait_for_unit("multi-user.target")
-    '';
-  };
+    # wait for grub screen
+    machine.wait_for_console_text("GNU GRUB")
 
-  # Test boot loader entries on BIOS
-  bls-bios = runTest {
-    name = "grub-bls-bios";
-    meta.maintainers = with pkgs.lib.maintainers; [ rnhmjoj ];
-
-    nodes.machine = { pkgs, ... }: {
-      virtualisation.useBootLoader = true;
-      boot.loader.grub.enable = true;
-    };
-
-    testScript = ''
-      with subtest("Machine boots correctly"):
-          machine.wait_for_unit("multi-user.target")
-
-      with subtest("Boot entries are installed"):
-          machine.succeed("test -f /boot/loader/entries/nixos-generation-1.conf")
-
-      with subtest("systemctl kexec can detect the kernel"):
-          machine.succeed("systemctl kexec --dry-run")
+    grub_select_all_configurations()
+    with subtest("Invalid credentials are rejected"):
+        grub_login_as("wronguser", "wrongsecret")
+        machine.wait_for_console_text("error: access denied.")
 
-      with subtest("systemctl kexec really works"):
-          machine.execute("systemctl kexec", check_return=False)
-          machine.connected = False
-          machine.connect()
-          machine.wait_for_unit("multi-user.target")
-    '';
-  };
+    grub_select_all_configurations()
+    with subtest("Valid credentials are accepted"):
+        grub_login_as("alice", "supersecret")
+        machine.send_chars("\n")  # press enter to boot
+        machine.wait_for_console_text("Linux version")
 
-}
+    with subtest("Machine boots correctly"):
+        machine.wait_for_unit("multi-user.target")
+  '';
+})

nixos/tests/nixos-rebuild-install-bootloader.nix

···
           # at this point we've tested regression #262724, but haven't tested the bootloader itself
           # TODO: figure out how to how to tell the test driver to start the bootloader instead of
           # booting into the kernel directly.
-
-      with subtest("New boot entry has been added"):
-          machine.succeed("test -f /boot/loader/entries/nixos-generation-2.conf")
     '';
 })