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.
This commit is contained in:
Luke Granger-Brown 2021-01-03 18:29:34 +00:00
parent 052231cf79
commit 13fad0f81b
2 changed files with 73 additions and 23 deletions

View file

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

View file

@ -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";