Commit 13fad0f8 authored by Luke Granger-Brown's avatar Luke Granger-Brown
Browse files

nixos/systemd-boot: create boot entries for specialisations 

Some specialisations (such as those which affect various boot-time
attributes) cannot be switched to at runtime. This allows picking the
specialisation at boot time.
parent 052231cf

nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py

+50 −23
Original line number Diff line number Diff line
@@ -17,19 +17,28 @@ import glob 
import os.path

from typing import Tuple, List, Optional



SystemIdentifier = Tuple[Optional[str], int, Optional[str]]





def copy_if_not_exists(source: str, dest: str) -> None:

    if not os.path.exists(dest):

        shutil.copyfile(source, dest)





def system_dir(profile: Optional[str], generation: int) -> str:

def generation_dir(profile: Optional[str], generation: int) -> str:

    if profile:

        return "/nix/var/nix/profiles/system-profiles/%s-%d-link" % (profile, generation)

    else:

        return "/nix/var/nix/profiles/system-%d-link" % (generation)



BOOT_ENTRY = """title NixOS{profile}

def system_dir(profile: Optional[str], generation: int, specialisation: Optional[str]) -> str:

    d = generation_dir(profile, generation)

    if specialisation:

        return os.path.join(d, "specialisation", specialisation)

    else:

        return d



BOOT_ENTRY = """title NixOS{profile}{specialisation}

version Generation {generation} {description}

linux {kernel}

initrd {initrd}
@@ -46,26 +55,34 @@ efi /efi/memtest86/BOOTX64.efi 
"""





def write_loader_conf(profile: Optional[str], generation: int) -> None:

def generation_conf_filename(profile: Optional[str], generation: int, specialisation: Optional[str]) -> str:

    pieces = [

        "nixos",

        profile or None,

        "generation",

        str(generation),

        f"specialisation-{specialisation}" if specialisation else None,

    ]

    return "-".join(p for p in pieces if p) + ".conf"





def write_loader_conf(profile: Optional[str], generation: int, specialisation: Optional[str]) -> None:

    with open("@efiSysMountPoint@/loader/loader.conf.tmp", 'w') as f:

        if "@timeout@" != "":

            f.write("timeout @timeout@\n")

        if profile:

            f.write("default nixos-%s-generation-%d.conf\n" % (profile, generation))

        else:

            f.write("default nixos-generation-%d.conf\n" % (generation))

        f.write("default %s\n" % generation_conf_filename(profile, generation, specialisation))

        if not @editor@:

            f.write("editor 0\n");

        f.write("console-mode @consoleMode@\n");

    os.rename("@efiSysMountPoint@/loader/loader.conf.tmp", "@efiSysMountPoint@/loader/loader.conf")





def profile_path(profile: Optional[str], generation: int, name: str) -> str:

    return os.path.realpath("%s/%s" % (system_dir(profile, generation), name))

def profile_path(profile: Optional[str], generation: int, specialisation: Optional[str], name: str) -> str:

    return os.path.realpath("%s/%s" % (system_dir(profile, generation, specialisation), name))





def copy_from_profile(profile: Optional[str], generation: int, name: str, dry_run: bool = False) -> str:

    store_file_path = profile_path(profile, generation, name)

def copy_from_profile(profile: Optional[str], generation: int, specialisation: Optional[str], name: str, dry_run: bool = False) -> str:

    store_file_path = profile_path(profile, generation, specialisation, name)

    suffix = os.path.basename(store_file_path)

    store_dir = os.path.basename(os.path.dirname(store_file_path))

    efi_file_path = "/efi/nixos/%s-%s.efi" % (store_dir, suffix)
@@ -95,19 +112,17 @@ def describe_generation(generation_dir: str) -> str: 
    return description





def write_entry(profile: Optional[str], generation: int, machine_id: str) -> None:

    kernel = copy_from_profile(profile, generation, "kernel")

    initrd = copy_from_profile(profile, generation, "initrd")

def write_entry(profile: Optional[str], generation: int, specialisation: Optional[str], machine_id: str) -> None:

    kernel = copy_from_profile(profile, generation, specialisation, "kernel")

    initrd = copy_from_profile(profile, generation, specialisation, "initrd")

    try:

        append_initrd_secrets = profile_path(profile, generation, "append-initrd-secrets")

        append_initrd_secrets = profile_path(profile, generation, specialisation, "append-initrd-secrets")

        subprocess.check_call([append_initrd_secrets, "@efiSysMountPoint@%s" % (initrd)])

    except FileNotFoundError:

        pass

    if profile:

        entry_file = "@efiSysMountPoint@/loader/entries/nixos-%s-generation-%d.conf" % (profile, generation)

    else:

        entry_file = "@efiSysMountPoint@/loader/entries/nixos-generation-%d.conf" % (generation)

    generation_dir = os.readlink(system_dir(profile, generation))

    entry_file = "@efiSysMountPoint@/loader/entries/%s" % (

        generation_conf_filename(profile, generation, specialisation))

    generation_dir = os.readlink(system_dir(profile, generation, specialisation))

    tmp_path = "%s.tmp" % (entry_file)

    kernel_params = "init=%s/init " % generation_dir
@@ -115,6 +130,7 @@ def write_entry(profile: Optional[str], generation: int, machine_id: str) -> Non 
        kernel_params = kernel_params + params_file.read()

    with open(tmp_path, 'w') as f:

        f.write(BOOT_ENTRY.format(profile=" [" + profile + "]" if profile else "",

                    specialisation=" (%s)" % specialisation if specialisation else "",

                    generation=generation,

                    kernel=kernel,

                    initrd=initrd,
@@ -133,7 +149,7 @@ def mkdir_p(path: str) -> None: 
            raise





def get_generations(profile: Optional[str] = None) -> List[Tuple[Optional[str], int]]:

def get_generations(profile: Optional[str] = None) -> List[SystemIdentifier]:

    gen_list = subprocess.check_output([

        "@nix@/bin/nix-env",

        "--list-generations",
@@ -145,10 +161,19 @@ def get_generations(profile: Optional[str] = None) -> List[Tuple[Optional[str], 
    gen_lines.pop()



    configurationLimit = @configurationLimit@

    return [ (profile, int(line.split()[0])) for line in gen_lines ][-configurationLimit:]

    configurations: List[SystemIdentifier] = [ (profile, int(line.split()[0]), None) for line in gen_lines ]

    return configurations[-configurationLimit:]





def get_specialisations(profile: Optional[str], generation: int, _: Optional[str]) -> List[SystemIdentifier]:

    specialisations_dir = os.path.join(

            system_dir(profile, generation, None), "specialisation")

    if not os.path.exists(specialisations_dir):

        return []

    return [(profile, generation, spec) for spec in os.listdir(specialisations_dir)]





def remove_old_entries(gens: List[Tuple[Optional[str], int]]) -> None:

def remove_old_entries(gens: List[SystemIdentifier]) -> None:

    rex_profile = re.compile("^@efiSysMountPoint@/loader/entries/nixos-(.*)-generation-.*\.conf$")

    rex_generation = re.compile("^@efiSysMountPoint@/loader/entries/nixos.*-generation-(.*)\.conf$")

    known_paths = []
@@ -243,6 +268,8 @@ def main() -> None: 
    for gen in gens:

        try:

            write_entry(*gen, machine_id)

            for specialisation in get_specialisations(*gen):

                write_entry(*specialisation, machine_id)

            if os.readlink(system_dir(*gen)) == args.default_config:

                write_loader_conf(*gen)

        except OSError as e:

nixos/tests/systemd-boot.nix

+23 −0
Original line number Diff line number Diff line
@@ -39,6 +39,29 @@ in 
    '';

  };



  # Check that specialisations create corresponding boot entries.

  specialisation = makeTest {

    name = "systemd-boot-specialisation";

    meta.maintainers = with pkgs.stdenv.lib.maintainers; [ lukegb ];



    machine = { pkgs, lib, ... }: {

      imports = [ common ];

      specialisation.something.configuration = {};

    };



    testScript = ''

      machine.start()

      machine.wait_for_unit("multi-user.target")



      machine.succeed(

          "test -e /boot/loader/entries/nixos-generation-1-specialisation-something.conf"

      )

      machine.succeed(

          "grep -q 'title NixOS (something)' /boot/loader/entries/nixos-generation-1-specialisation-something.conf"

      )

    '';

  };



  # Boot without having created an EFI entry--instead using default "/EFI/BOOT/BOOTX64.EFI"

  fallback = makeTest {

    name = "systemd-boot-fallback";