kernel-update: cleanup, make specifying version optional

Signed-off-by: Martin Matous <m@matous.dev>

README.md

@@ -79,7 +79,11 @@ Status: active use
 
 Dependencies: dracut, Gentoo (not really but eselect, specific names and paths...)
 
-Usage: `kernel-update.py update <old-version> <new-version>`
+This will update kernel using `/usr/src/linux/.config` to the latest installed `sys-kernel/gentoo-sources`.
+
+Usage: `kernel-update.py`
+
+Alt.: `kernel-update.py <old-version> <new-version>`
 
 
 ---
@@ -152,4 +156,4 @@ Status: one-off
 
 Dependencies: pykeepass
 
-Usage: `try-luks-from-kdbx.py /path/to/kdbx /path/to/block-device`
+Usage: `try-luks-from-kdbx.py /path/to/kdbx /path/to/block-device`

kernel-update.py

@@ -1,14 +1,12 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import argparse
 import os
 import shutil
 import subprocess
 import sys
-
 from pathlib import Path
 
-
 SRC_DIR = Path('/usr/src')
 BOOT_DIR = Path('/boot')
 
@@ -16,56 +14,50 @@ BOOT_DIR = Path('/boot')
 def update_config(old_dir: Path, new_dir: Path, make_cmd: list[str]) -> None:
 	if old_dir == new_dir:
 		return
-	old_config = old_dir/'.config'
+	old_config = old_dir / '.config'
-	new_config = new_dir/'.config'
+	new_config = new_dir / '.config'
 	while new_config.is_file():
-		response = input('New config present. Overwrite? [y/N]').strip().lower()
+		response = input('New config present. Overwrite? [y/N]\n').strip().lower()
 		if response == 'y':
 			break
-		elif response == '' or response == 'n':
+		elif response in ('', 'n'):
 			return
 		else:
-			print("unrecognized option {}", response)
+			print('unrecognized option {}', response)
 	print(f'Copying config from {old_config} to {new_config}')
 	shutil.copy2(old_config, new_config)
 
 	print(f'Setting symlink to {new_dir}')
-	subprocess.run(['eselect', 'kernel', 'set', new_dir.name])
+	(SRC_DIR / 'linux').symlink_to(new_dir, target_is_directory=True)
 	print('Migrating config options')
-	migrate = make_cmd + ['-C', new_dir.as_posix(), 'oldconfig']
+	migrate = [*make_cmd, '--directory', new_dir.as_posix(), 'oldconfig']
-	subprocess.run(migrate)
+	subprocess.run(migrate, check=True)
-	menuconfig = make_cmd + ['-C', new_dir.as_posix(), 'menuconfig']
+	menuconfig = [*make_cmd, '--directory', new_dir.as_posix(), 'menuconfig']
 	while True:
-		subprocess.run(menuconfig)
+		subprocess.run(menuconfig, check=True)
 		response = input('Stop editing? [Y/n]').strip().lower()
-		if response == '' or response == 'y':
+		if response in ('', 'y'):
 			break
 		elif response == 'n':
 			continue
 		else:
-			print("unrecognized option {}", response)
+			print('unrecognized option {}', response)
 
 
 def compile_kernel(new_dir: Path, make_cmd: list[str]) -> None:
-	cc = make_cmd + ['-C', new_dir.as_posix()]
+	cc = [*make_cmd, '--directory', new_dir.as_posix()]
-	subprocess.run(cc)
+	subprocess.run(cc, check=True)
 
 
 def install_kernel(kernel_dir: Path, make_cmd: list[str], kver: str) -> None:
-	install_modules = make_cmd + ['-C', kernel_dir.as_posix(), 'modules_install']
+	install_modules = [*make_cmd, '--directory', kernel_dir.as_posix(), 'modules_install']
-	subprocess.run(install_modules)
+	subprocess.run(install_modules, check=True)
-
+	kver = kver[6:]  # drop "linux-" prefix
-	kver = kver[6:]
+	# assumes proper dracut config in /etc, incl. signing keys
-	# assumes proper dracut config in /etc
 	dracut = ['dracut', f'--kver={kver}', '--force', '--no-machineid']
-	res = subprocess.run(dracut)
+	res = subprocess.run(dracut, check=True)
-
 	print(res)
-	return
+
-	# todo: sign uki
-	uki_dir = res.split('')
-	sign_uki = ['sbctl', 'bundle', '--save', '']
-	subprocess.run(sign_uki)
 
 def linux_folder(src_dir: Path, version: str) -> Path:
 	revision = ''
@@ -73,19 +65,19 @@ def linux_folder(src_dir: Path, version: str) -> Path:
 	if len(version) > 1:
 		revision = '-' + version[1]
 	version = version[0]
-	return (src_dir / (f'linux-{version}-gentoo{revision}'))
+	return src_dir / (f'linux-{version}-gentoo{revision}')
 
 
-def update_kernel(boot_dir: Path, args: argparse.Namespace) -> None:
+def update_kernel(args: argparse.Namespace) -> None:
 	old_dir = linux_folder(SRC_DIR, args.old_version)
 	new_dir = linux_folder(SRC_DIR, args.new_version)
 	new_version = new_dir.name
-	make_cmd = ['make', f'-j{len(os.sched_getaffinity(0))}']
+	make_cmd = ['make', f'--jobs={len(os.sched_getaffinity(0))}']
-	# https://docs.kernel.org/kbuild/llvm.html
 
 	if args.llvm:
+		# https://docs.kernel.org/kbuild/llvm.html
 		make_cmd.extend(['LLVM=1'])
-	none_selected = not (args.backup or args.config or args.compile or args.install or args.rollback)
+	none_selected = not any((args.config, args.compile, args.install))
 	if none_selected:
 		update_config(old_dir, new_dir, make_cmd)
 		compile_kernel(new_dir, make_cmd)
@@ -97,38 +89,27 @@ def update_kernel(boot_dir: Path, args: argparse.Namespace) -> None:
 	if args.install:
 		install_kernel(new_dir, make_cmd, new_version)
 
-def main() -> None:
-	parser = argparse.ArgumentParser(description='Convenience for manual kernel updates')
-	subparsers = parser.add_subparsers()
 
-	update = subparsers.add_parser('update',
+def main() -> None:
-		usage=f'{sys.argv[0]} update 5.15.12 5.16.3',
+	parser = argparse.ArgumentParser(description='Helper for manual kernel updates', usage=f'{sys.argv[0]}')
-	)
+	parser.add_argument('--llvm', '-l', action='store_true', help='Use clang/llvm to compile kernel')
-	update.add_argument(
+	parser.add_argument('--config', '-C', action='store_true', help='Migrate config from old kernel')
-		'--llvm', '-l', action='store_true',
+	parser.add_argument('--compile', '-c', action='store_true', help='Compile new kernel')
-		help="Use clang/llvm to compile kernel")
+	parser.add_argument('--install', '-i', action='store_true', help='Install new kernel')
-	update.add_argument(
+	parser.add_argument('old_version', help='Old kernel version (optional)', nargs='?', default=None)
-		'--backup', '-b', action='store_true',
+	parser.add_argument('new_version', help='New kernel version (optional)', nargs='?', default=None)
-		help="Backup old kernel files as .old")
-	update.add_argument(
-		'--rollback', '-r', action='store_true',
-		help='Restore .old kernel files as main boot choice')
-	update.add_argument(
-		'--config', '-C', action='store_true',
-		help='Migrate config from old kernel')
-	update.add_argument(
-		'--compile', '-c', action='store_true',
-		help='Compile new kernel')
-	update.add_argument(
-		'--install', '-i', action='store_true',
-		help='Install new kernel')
-	update.add_argument('old_version', help='Old kernel version')
-	update.add_argument('new_version', help='New kernel version')
-	update.set_defaults(func=update_kernel)
 
 	args = parser.parse_args()
-	args.func(BOOT_DIR, args)
+	if args.old_version and not args.new_version:
+		args.new_version = args.old_version
+		args.old_version = None
+	if not args.old_version:
+		args.old_version = (SRC_DIR / 'linux').readlink().name.split('-')[1]
+	if not args.new_version:
+		subdirs = Path(SRC_DIR).glob('linux-*-gentoo*')  # too broad but good enough, blame fnmatch
+		args.new_version = sorted(subdir.name for subdir in subdirs if subdir.is_dir())[-1].split('-')[1]
+	update_kernel(args)
 
 
-if __name__ == "__main__":
+if __name__ == '__main__':
 	main()