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Create ESP boot from bootspec (#248)
* Add script to generate ESP partition by bootspec Signed-off-by: Alexander V. Nikolaev <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,187 @@ | ||
| #! @python3@/bin/python3 -B | ||
| """This is opinionated rewrite of nixos/modules/system/boot/loader/systemd-boot/systemd-boot-builder.py, | ||
| as well as re-implement some logic from bootctl tool. | ||
| Two main goals: | ||
| * Use bootspec JSON as primary source of truth about system | ||
| * Be enough close to standard bootctl behavior, to allow local system updates | ||
| """ | ||
| import argparse | ||
| import errno | ||
| import json | ||
| import os | ||
| import shutil | ||
| import sys | ||
| from typing import Optional, Union, List, Dict, TypedDict | ||
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| BOOT_ENTRY = """title {title} | ||
| version Generation {generation} {description} | ||
| linux {kernel} | ||
| initrd {initrd} | ||
| options {kernel_params} | ||
| """ | ||
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| LOADER_CONF = """timeout 0 | ||
| default nixos-generation-1.conf | ||
| console-mode keep | ||
| """ | ||
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| LOADERS = { | ||
| "x86_64-linux": ("systemd-bootx64.efi", "BOOTX64.efi"), | ||
| "aarch64-linux": ("systemd-bootaa64.efi", "BOOTAA64.efi"), | ||
| } | ||
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| class BootSpec(TypedDict): | ||
| kernel: str | ||
| initrd: str | ||
| init: str | ||
| kernelParams: List[str] | ||
| system: str | ||
| label: str | ||
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| def eprint(*args: str) -> None: | ||
| print(*args, file=sys.stderr) | ||
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| def mkdir_p(path: str) -> None: | ||
| if os.path.isdir(path): | ||
| return | ||
| eprint(f"Create directory {path}") | ||
| try: | ||
| os.makedirs(path) | ||
| except OSError as e: | ||
| if e.errno != errno.EEXIST or not os.path.isdir(path): | ||
| raise | ||
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| def write_file(path: str, content: str) -> None: | ||
| mkdir_p(os.path.dirname(path)) | ||
| eprint(f"Writing {path}") | ||
| with open(path, "w") as f: | ||
| f.write(content) | ||
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| def ensure_file(name: str) -> None: | ||
| if os.path.exists(name): | ||
| eprint(f"Found required file {name}") | ||
| else: | ||
| eprint(f"Can't find required file {name}") | ||
| sys.exit(1) | ||
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| def copy_file(src: str, dst: str) -> None: | ||
| mkdir_p(os.path.dirname(dst)) | ||
| eprint(f"Copying {src} to {dst}") | ||
| shutil.copy(src, dst) | ||
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| def make_efi_name(store_file_path: str, root: str = "/") -> str: | ||
| suffix = os.path.basename(store_file_path) | ||
| store_dir = os.path.basename(os.path.dirname(store_file_path)) | ||
| return os.path.join(root, "EFI/nixos/%s-%s.efi" % (store_dir, suffix)) | ||
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| def copy_loader(loader: str, esp: str, target_name: str) -> None: | ||
| efi = os.path.join(esp, "EFI") | ||
| copy_file(loader, os.path.join(efi, "systemd", os.path.basename(loader))) | ||
| copy_file(loader, os.path.join(efi, "BOOT", target_name)) | ||
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| def copy_nixos(esp: str, kernel: str, initrd: str, dtb: Optional[str] = None) -> None: | ||
| copy_file(kernel, make_efi_name(kernel, esp)) | ||
| copy_file(initrd, make_efi_name(initrd, esp)) | ||
| if dtb: | ||
| copy_file(dtb, make_efi_name(dtb, esp)) | ||
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| def write_loader_entry( | ||
| esp: str, | ||
| boot: BootSpec, | ||
| kernel_params: List[str], | ||
| machine_id: Optional[str], | ||
| random_seed: Optional[str], | ||
| device_tree: Optional[str], | ||
| ) -> None: | ||
| entry = BOOT_ENTRY.format( | ||
| kernel=make_efi_name(boot["kernel"]), | ||
| initrd=make_efi_name(boot["initrd"]), | ||
| init=boot["init"], | ||
| kernel_params=" ".join(kernel_params), | ||
| description=boot["label"], | ||
| generation=1, | ||
| title="NixOS", | ||
| ) | ||
| if machine_id: | ||
| entry += f"machine-id {machine_id}" | ||
|
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| if device_tree: | ||
| dt = make_efi_name(device_tree) | ||
| entry += f"\ndevicetree /{dt}" | ||
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| write_file(os.path.join(esp, "loader/entries/nixos-generation-1.conf"), entry) | ||
| write_file(os.path.join(esp, "loader/loader.conf"), LOADER_CONF) | ||
| write_file(os.path.join(esp, "loader/entries.srel"), "type1\n") | ||
| if random_seed: | ||
| copy_file(random_seed, os.path.join(esp, "loader/random_seed")) | ||
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| def read_bootspec_file(toplevel: str) -> BootSpec: | ||
| bootfile = os.path.join(toplevel, "boot.json") | ||
| ensure_file(bootfile) | ||
| with open(bootfile, "r") as boot_json: | ||
| content = json.load(boot_json) | ||
| bootspec: Optional[BootSpec] = content.get("org.nixos.bootspec.v1") | ||
| if bootspec is None: | ||
| eprint(f"""Can't find "org.nixos.bootspec.v1" in {bootfile}""") | ||
| sys.exit(1) | ||
| return bootspec | ||
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| def create_esp_contents( | ||
| toplevel: str, | ||
| output: str, | ||
| machine_id: Optional[str], | ||
| random_seed: Optional[str], | ||
| device_tree: Optional[str], | ||
| ) -> None: | ||
| mkdir_p(output) | ||
| boot = read_bootspec_file(toplevel) | ||
| system = boot["system"] | ||
| selected_loader = LOADERS.get(system) | ||
| if selected_loader is None: | ||
| eprint(f"Haven't loader for system {system}") | ||
| sys.exit(1) | ||
| (loader, target_loader_filename) = selected_loader | ||
| loader = os.path.join(toplevel, "systemd/lib/systemd/boot/efi", loader) | ||
| ensure_file(loader) | ||
| copy_loader(loader, output, target_loader_filename) | ||
| copy_nixos(output, boot["kernel"], boot["initrd"], device_tree) | ||
| kernel_params = boot["kernelParams"] | ||
| init = boot["init"] | ||
| kernel_params.insert(0, f"init={init}") | ||
| write_loader_entry( | ||
| output, boot, kernel_params, machine_id, random_seed, device_tree | ||
| ) | ||
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| def main() -> None: | ||
| parser = argparse.ArgumentParser(description="Generate contents of ESP partition") | ||
| parser.add_argument( | ||
| "--toplevel", help="NixOS toplevel directory, contains boot.json" | ||
| ) | ||
| parser.add_argument("--output", help="Output directory") | ||
| parser.add_argument("--device-tree", default=None, help="Device tree file") | ||
| parser.add_argument("--random-seed", default=None, help="Random seed file") | ||
| parser.add_argument( | ||
| "--machine-id", default=None, help="Machine id to add to loader's entry" | ||
| ) | ||
| args = parser.parse_args() | ||
| create_esp_contents( | ||
| args.toplevel, args.output, args.machine_id, args.random_seed, args.device_tree | ||
| ) | ||
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| if __name__ == "__main__": | ||
| main() |
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