ukify: Type-annotate ukify

src/ukify/mypy.ini

@@ -0,0 +1,21 @@
+[mypy]
+python_version = 3.9
+allow_redefinition = True
+# belonging to --strict
+warn_unused_configs = true
+disallow_untyped_calls = true
+disallow_untyped_defs = true
+disallow_untyped_decorators = true
+disallow_incomplete_defs = true
+check_untyped_defs = true
+no_implicit_optional = true
+warn_redundant_casts = true
+warn_unused_ignores = false
+warn_return_any = true
+no_implicit_reexport = true
+# extra options not in --strict
+pretty = true
+show_error_codes = true
+show_column_numbers = true
+warn_unreachable = true
+strict_equality = true

src/ukify/ukify.py

@@ -40,15 +40,18 @@ import subprocess
 import sys
 import tempfile
 import textwrap
-from collections.abc import Sequence
+from collections.abc import Iterable, Iterator, Sequence
 from hashlib import sha256
 from pathlib import Path
+from types import ModuleType
 from typing import (
     IO,
     Any,
     Callable,
     Optional,
+    TypeVar,
     Union,
+    cast,
 )
 
 import pefile  # type: ignore
@@ -83,7 +86,7 @@ class Style:
     reset = '\033[0m' if sys.stderr.isatty() else ''
 
 
-def guess_efi_arch():
+def guess_efi_arch() -> str:
     arch = os.uname().machine
 
     for glob, mapping in EFI_ARCH_MAP.items():
@@ -118,23 +121,23 @@ def page(text: str, enabled: Optional[bool]) -> None:
         print(text)
 
 
-def shell_join(cmd):
+def shell_join(cmd: list[Union[str, Path]]) -> str:
     # TODO: drop in favour of shlex.join once shlex.join supports Path.
     return ' '.join(shlex.quote(str(x)) for x in cmd)
 
 
-def round_up(x, blocksize=4096):
+def round_up(x: int, blocksize: int = 4096) -> int:
     return (x + blocksize - 1) // blocksize * blocksize
 
 
-def try_import(modname, name=None):
+def try_import(modname: str, name: Optional[str] = None) -> ModuleType:
     try:
         return __import__(modname)
     except ImportError as e:
         raise ValueError(f'Kernel is compressed with {name or modname}, but module unavailable') from e
 
 
-def get_zboot_kernel(f):
+def get_zboot_kernel(f: IO[bytes]) -> bytes:
     """Decompress zboot efistub kernel if compressed. Return contents."""
     # See linux/drivers/firmware/efi/libstub/Makefile.zboot
     # and linux/drivers/firmware/efi/libstub/zboot-header.S
@@ -157,25 +160,25 @@ def get_zboot_kernel(f):
     f.seek(start)
     if comp_type.startswith(b'gzip'):
         gzip = try_import('gzip')
-        return gzip.open(f).read(size)
+        return cast(bytes, gzip.open(f).read(size))
     elif comp_type.startswith(b'lz4'):
         lz4 = try_import('lz4.frame', 'lz4')
-        return lz4.frame.decompress(f.read(size))
+        return cast(bytes, lz4.frame.decompress(f.read(size)))
     elif comp_type.startswith(b'lzma'):
         lzma = try_import('lzma')
-        return lzma.open(f).read(size)
+        return cast(bytes, lzma.open(f).read(size))
     elif comp_type.startswith(b'lzo'):
         raise NotImplementedError('lzo decompression not implemented')
     elif comp_type.startswith(b'xzkern'):
         raise NotImplementedError('xzkern decompression not implemented')
     elif comp_type.startswith(b'zstd22'):
         zstd = try_import('zstd')
-        return zstd.uncompress(f.read(size))
-    else:
-        raise NotImplementedError(f'unknown compressed type: {comp_type}')
+        return cast(bytes, zstd.uncompress(f.read(size)))
+
+    raise NotImplementedError(f'unknown compressed type: {comp_type!r}')
 
 
-def maybe_decompress(filename):
+def maybe_decompress(filename: Union[str, Path]) -> bytes:
     """Decompress file if compressed. Return contents."""
     f = open(filename, 'rb')
     start = f.read(4)
@@ -197,20 +200,20 @@ def maybe_decompress(filename):
 
     if start.startswith(b'\x1f\x8b'):
         gzip = try_import('gzip')
-        return gzip.open(f).read()
+        return cast(bytes, gzip.open(f).read())
 
     if start.startswith(b'\x28\xb5\x2f\xfd'):
         zstd = try_import('zstd')
-        return zstd.uncompress(f.read())
+        return cast(bytes, zstd.uncompress(f.read()))
 
     if start.startswith(b'\x02\x21\x4c\x18'):
         lz4 = try_import('lz4.frame', 'lz4')
-        return lz4.frame.decompress(f.read())
+        return cast(bytes, lz4.frame.decompress(f.read()))
 
     if start.startswith(b'\x04\x22\x4d\x18'):
         print('Newer lz4 stream format detected! This may not boot!')
         lz4 = try_import('lz4.frame', 'lz4')
-        return lz4.frame.decompress(f.read())
+        return cast(bytes, lz4.frame.decompress(f.read()))
 
     if start.startswith(b'\x89LZO'):
         # python3-lzo is not packaged for Fedora
@@ -218,13 +221,13 @@ def maybe_decompress(filename):
 
     if start.startswith(b'BZh'):
         bz2 = try_import('bz2', 'bzip2')
-        return bz2.open(f).read()
+        return cast(bytes, bz2.open(f).read())
 
     if start.startswith(b'\x5d\x00\x00'):
         lzma = try_import('lzma')
-        return lzma.open(f).read()
+        return cast(bytes, lzma.open(f).read())
 
-    raise NotImplementedError(f'unknown file format (starts with {start})')
+    raise NotImplementedError(f'unknown file format (starts with {start!r})')
 
 
 class Uname:
@@ -240,7 +243,7 @@ class Uname:
     TEXT_PATTERN = rb'Linux version (?P<version>\d\.\S+) \('
 
     @classmethod
-    def scrape_x86(cls, filename, opts=None):
+    def scrape_x86(cls, filename: Path, opts: Optional[argparse.Namespace] = None) -> str:
         # Based on https://gitlab.archlinux.org/archlinux/mkinitcpio/mkinitcpio/-/blob/master/functions#L136
         # and https://docs.kernel.org/arch/x86/boot.html#the-real-mode-kernel-header
         with open(filename, 'rb') as f:
@@ -253,15 +256,17 @@ class Uname:
             f.seek(0x200 + offset)
             text = f.read(128)
         text = text.split(b'\0', maxsplit=1)[0]
-        text = text.decode()
+        decoded = text.decode()
 
-        if not (m := re.match(cls.VERSION_PATTERN, text)):
+        if not (m := re.match(cls.VERSION_PATTERN, decoded)):
             raise ValueError(f'Cannot parse version-host-release uname string: {text!r}')
         return m.group('version')
 
     @classmethod
-    def scrape_elf(cls, filename, opts=None):
+    def scrape_elf(cls, filename: Path, opts: Optional[argparse.Namespace] = None) -> str:
         readelf = find_tool('readelf', opts=opts)
+        if not readelf:
+            raise ValueError('FIXME')
 
         cmd = [
             readelf,
@@ -282,7 +287,7 @@ class Uname:
         return text.rstrip('\0')
 
     @classmethod
-    def scrape_generic(cls, filename, opts=None):
+    def scrape_generic(cls, filename: Path, opts: Optional[argparse.Namespace] = None) -> str:
         # import libarchive
         # libarchive-c fails with
         # ArchiveError: Unrecognized archive format (errno=84, retcode=-30, archive_p=94705420454656)
@@ -296,7 +301,7 @@ class Uname:
         return m.group('version').decode()
 
     @classmethod
-    def scrape(cls, filename, opts=None):
+    def scrape(cls, filename: Path, opts: Optional[argparse.Namespace] = None) -> Optional[str]:
         for func in (cls.scrape_x86, cls.scrape_elf, cls.scrape_generic):
             try:
                 version = func(filename, opts=opts)
@@ -328,13 +333,13 @@ DEFAULT_SECTIONS_TO_SHOW = {
 class Section:
     name: str
     content: Optional[Path]
-    tmpfile: Optional[IO] = None
+    tmpfile: Optional[IO[Any]] = None
     measure: bool = False
     output_mode: Optional[str] = None
     virtual_size: Optional[int] = None
 
     @classmethod
-    def create(cls, name, contents, **kwargs):
+    def create(cls, name: str, contents: Union[str, bytes, Path, None], **kwargs: Any) -> 'Section':
         if isinstance(contents, (str, bytes)):
             mode = 'wt' if isinstance(contents, str) else 'wb'
             tmp = tempfile.NamedTemporaryFile(mode=mode, prefix=f'tmp{name}')
@@ -347,7 +352,7 @@ class Section:
         return cls(name, contents, tmpfile=tmp, **kwargs)
 
     @classmethod
-    def parse_input(cls, s):
+    def parse_input(cls, s: str) -> 'Section':
         try:
             name, contents, *rest = s.split(':')
         except ValueError as e:
@@ -356,14 +361,15 @@ class Section:
             raise ValueError(f'Cannot parse section spec (extraneous parameters): {s!r}')
 
         if contents.startswith('@'):
-            contents = Path(contents[1:])
+            sec = cls.create(name, Path(contents[1:]))
+        else:
+            sec = cls.create(name, contents)
 
-        sec = cls.create(name, contents)
         sec.check_name()
         return sec
 
     @classmethod
-    def parse_output(cls, s):
+    def parse_output(cls, s: str) -> 'Section':
         if not (m := re.match(r'([a-zA-Z0-9_.]+):(text|binary)(?:@(.+))?', s)):
             raise ValueError(f'Cannot parse section spec: {s!r}')
 
@@ -372,7 +378,7 @@ class Section:
 
         return cls.create(name, out, output_mode=ttype)
 
-    def check_name(self):
+    def check_name(self) -> None:
         # PE section names with more than 8 characters are legal, but our stub does
         # not support them.
         if not self.name.isascii() or not self.name.isprintable():
@@ -386,7 +392,7 @@ class UKI:
     executable: list[Union[Path, str]]
     sections: list[Section] = dataclasses.field(default_factory=list, init=False)
 
-    def add_section(self, section):
+    def add_section(self, section: Section) -> None:
         start = 0
 
         # Start search at last .profile section, if there is one
@@ -400,7 +406,7 @@ class UKI:
         self.sections += [section]
 
 
-def parse_banks(s):
+def parse_banks(s: str) -> list[str]:
     banks = re.split(r',|\s+', s)
     # TODO: do some sanity checking here
     return banks
@@ -416,7 +422,7 @@ KNOWN_PHASES = (
 )
 
 
-def parse_phase_paths(s):
+def parse_phase_paths(s: str) -> list[str]:
     # Split on commas or whitespace here. Commas might be hard to parse visually.
     paths = re.split(r',|\s+', s)
 
@@ -428,7 +434,7 @@ def parse_phase_paths(s):
     return paths
 
 
-def check_splash(filename):
+def check_splash(filename: Optional[str]) -> None:
     if filename is None:
         return
 
@@ -442,7 +448,7 @@ def check_splash(filename):
     print(f'Splash image {filename} is {img.width}×{img.height} pixels')
 
 
-def check_inputs(opts):
+def check_inputs(opts: argparse.Namespace) -> None:
     for name, value in vars(opts).items():
         if name in {'output', 'tools'}:
             continue
@@ -458,7 +464,7 @@ def check_inputs(opts):
     check_splash(opts.splash)
 
 
-def check_cert_and_keys_nonexistent(opts):
+def check_cert_and_keys_nonexistent(opts: argparse.Namespace) -> None:
     # Raise if any of the keys and certs are found on disk
     paths = itertools.chain(
         (opts.sb_key, opts.sb_cert),
@@ -469,12 +475,16 @@ def check_cert_and_keys_nonexistent(opts):
             raise ValueError(f'{path} is present')
 
 
-def find_tool(name, fallback=None, opts=None):
+def find_tool(
+    name: str,
+    fallback: Optional[str] = None,
+    opts: Optional[argparse.Namespace] = None,
+) -> Union[str, Path, None]:
     if opts and opts.tools:
         for d in opts.tools:
             tool = d / name
             if tool.exists():
-                return tool
+                return cast(Path, tool)
 
     if shutil.which(name) is not None:
         return name
@@ -485,8 +495,8 @@ def find_tool(name, fallback=None, opts=None):
     return fallback
 
 
-def combine_signatures(pcrsigs):
-    combined = collections.defaultdict(list)
+def combine_signatures(pcrsigs: list[dict[str, str]]) -> str:
+    combined: collections.defaultdict[str, list[str]] = collections.defaultdict(list)
     for pcrsig in pcrsigs:
         for bank, sigs in pcrsig.items():
             for sig in sigs:
@@ -495,7 +505,7 @@ def combine_signatures(pcrsigs):
     return json.dumps(combined)
 
 
-def key_path_groups(opts):
+def key_path_groups(opts: argparse.Namespace) -> Iterator:
     if not opts.pcr_private_keys:
         return
 
@@ -510,16 +520,18 @@ def key_path_groups(opts):
     )
 
 
-def pe_strip_section_name(name):
+def pe_strip_section_name(name: bytes) -> str:
     return name.rstrip(b'\x00').decode()
 
 
-def call_systemd_measure(uki, opts, profile_start=0):
+def call_systemd_measure(uki: UKI, opts: argparse.Namespace, profile_start: int = 0) -> None:
     measure_tool = find_tool(
         'systemd-measure',
         '/usr/lib/systemd/systemd-measure',
         opts=opts,
     )
+    if not measure_tool:
+        raise ValueError('FIXME')
 
     banks = opts.pcr_banks or ()
 
@@ -583,8 +595,8 @@ def call_systemd_measure(uki, opts, profile_start=0):
                 extra += [f'--public-key={pub_key}']
             extra += [f'--phase={phase_path}' for phase_path in group or ()]
 
-            print('+', shell_join(cmd + extra))
-            pcrsig = subprocess.check_output(cmd + extra, text=True)
+            print('+', shell_join(cmd + extra))  # type: ignore
+            pcrsig = subprocess.check_output(cmd + extra, text=True)  # type: ignore
             pcrsig = json.loads(pcrsig)
             pcrsigs += [pcrsig]
 
@@ -592,7 +604,7 @@ def call_systemd_measure(uki, opts, profile_start=0):
         uki.add_section(Section.create('.pcrsig', combined))
 
 
-def join_initrds(initrds):
+def join_initrds(initrds: list[Path]) -> Union[Path, bytes, None]:
     if not initrds:
         return None
     if len(initrds) == 1:
@@ -608,7 +620,10 @@ def join_initrds(initrds):
     return b''.join(seq)
 
 
-def pairwise(iterable):
+T = TypeVar('T')
+
+
+def pairwise(iterable: Iterable[T]) -> Iterator[tuple[T, Optional[T]]]:
     a, b = itertools.tee(iterable)
     next(b, None)
     return zip(a, b)
@@ -618,7 +633,7 @@ class PEError(Exception):
     pass
 
 
-def pe_add_sections(uki: UKI, output: str):
+def pe_add_sections(uki: UKI, output: str) -> None:
     pe = pefile.PE(uki.executable, fast_load=True)
 
     # Old stubs do not have the symbol/string table stripped, even though image files should not have one.
@@ -750,7 +765,7 @@ def pe_add_sections(uki: UKI, output: str):
     pe.write(output)
 
 
-def merge_sbat(input_pe: [Path], input_text: [str]) -> str:
+def merge_sbat(input_pe: list[Path], input_text: list[str]) -> str:
     sbat = []
 
     for f in input_pe:
@@ -786,16 +801,21 @@ def merge_sbat(input_pe: [Path], input_text: [str]) -> str:
     )
 
 
-def signer_sign(cmd):
+def signer_sign(cmd: list[Union[str, Path]]) -> None:
     print('+', shell_join(cmd))
     subprocess.check_call(cmd)
 
 
-def find_sbsign(opts=None):
+def find_sbsign(opts: Optional[argparse.Namespace] = None) -> Union[str, Path, None]:
     return find_tool('sbsign', opts=opts)
 
 
-def sbsign_sign(sbsign_tool, input_f, output_f, opts=None):
+def sbsign_sign(
+    sbsign_tool: Union[str, Path],
+    input_f: str,
+    output_f: str,
+    opts: argparse.Namespace,
+) -> None:
     sign_invocation = [
         sbsign_tool,
         '--key', opts.sb_key,
@@ -810,11 +830,16 @@ def sbsign_sign(sbsign_tool, input_f, output_f, opts=None):
     signer_sign(sign_invocation)
 
 
-def find_pesign(opts=None):
+def find_pesign(opts: Optional[argparse.Namespace] = None) -> Union[str, Path, None]:
     return find_tool('pesign', opts=opts)
 
 
-def pesign_sign(pesign_tool, input_f, output_f, opts=None):
+def pesign_sign(
+    pesign_tool: Union[str, Path],
+    input_f: str,
+    output_f: str,
+    opts: argparse.Namespace,
+) -> None:
     sign_invocation = [
         pesign_tool,
         '-s',
@@ -841,7 +866,7 @@ PESIGCHECK = {
 }
 
 
-def verify(tool, opts):
+def verify(tool: dict[str, str], opts: argparse.Namespace) -> bool:
     verify_tool = find_tool(tool['name'], opts=opts)
     cmd = [
         verify_tool,
@@ -857,13 +882,13 @@ def verify(tool, opts):
     return tool['output'] in info
 
 
-def make_uki(opts):
+def make_uki(opts: argparse.Namespace) -> None:
     # kernel payload signing
 
     sign_tool = None
     sign_args_present = opts.sb_key or opts.sb_cert_name
     sign_kernel = opts.sign_kernel
-    sign = None
+    sign: Optional[Callable[[Union[str, Path], str, str, argparse.Namespace], None]] = None
     linux = opts.linux
 
     if sign_args_present:
@@ -884,6 +909,8 @@ def make_uki(opts):
             sign_kernel = verify(verify_tool, opts)
 
         if sign_kernel:
+            assert sign is not None
+            assert sign_tool is not None
             linux_signed = tempfile.NamedTemporaryFile(prefix='linux-signed')
             linux = Path(linux_signed.name)
             sign(sign_tool, opts.linux, linux, opts=opts)
@@ -1051,8 +1078,9 @@ uki-addon,1,UKI Addon,addon,1,https://www.freedesktop.org/software/systemd/man/l
     # UKI signing
 
     if sign_args_present:
-        assert sign
-        sign(sign_tool, unsigned_output, opts.output, opts=opts)
+        assert sign is not None
+        assert sign_tool is not None
+        sign(sign_tool, unsigned_output, opts.output, opts)
 
         # We end up with no executable bits, let's reapply them
         os.umask(umask := os.umask(0))
@@ -1062,7 +1090,7 @@ uki-addon,1,UKI Addon,addon,1,https://www.freedesktop.org/software/systemd/man/l
 
 
 @contextlib.contextmanager
-def temporary_umask(mask: int):
+def temporary_umask(mask: int) -> Iterator[None]:
     # Drop <mask> bits from umask
     old = os.umask(0)
     os.umask(old | mask)
@@ -1076,7 +1104,7 @@ def generate_key_cert_pair(
     common_name: str,
     valid_days: int,
     keylength: int = 2048,
-) -> tuple[bytes]:
+) -> tuple[bytes, bytes]:
     from cryptography import x509
     from cryptography.hazmat.primitives import hashes, serialization
     from cryptography.hazmat.primitives.asymmetric import rsa
@@ -1133,7 +1161,7 @@ def generate_key_cert_pair(
     return key_pem, cert_pem
 
 
-def generate_priv_pub_key_pair(keylength: int = 2048) -> tuple[bytes]:
+def generate_priv_pub_key_pair(keylength: int = 2048) -> tuple[bytes, bytes]:
     from cryptography.hazmat.primitives import serialization
     from cryptography.hazmat.primitives.asymmetric import rsa
 
@@ -1154,7 +1182,7 @@ def generate_priv_pub_key_pair(keylength: int = 2048) -> tuple[bytes]:
     return priv_key_pem, pub_key_pem
 
 
-def generate_keys(opts):
+def generate_keys(opts: argparse.Namespace) -> None:
     work = False
 
     # This will generate keys and certificates and write them to the paths that
@@ -1192,7 +1220,10 @@ def generate_keys(opts):
         )
 
 
-def inspect_section(opts, section):
+def inspect_section(
+    opts: argparse.Namespace,
+    section: pefile.SectionStructure,
+) -> tuple[str, Optional[dict[str, Union[int, str]]]]:
     name = pe_strip_section_name(section.Name)
 
     # find the config for this section in opts and whether to show it
@@ -1233,7 +1264,7 @@ def inspect_section(opts, section):
     return name, struct
 
 
-def inspect_sections(opts):
+def inspect_sections(opts: argparse.Namespace) -> None:
     indent = 4 if opts.json == 'pretty' else None
 
     for file in opts.files:
@@ -1348,7 +1379,7 @@ class ConfigItem:
             return self.dest
         return self._names()[0].lstrip('-').replace('-', '_')
 
-    def add_to(self, parser: argparse.ArgumentParser):
+    def add_to(self, parser: argparse.ArgumentParser) -> None:
         kwargs = {
             key: val
             for key in dataclasses.asdict(self)
@@ -1357,7 +1388,14 @@ class ConfigItem:
         args = self._names()
         parser.add_argument(*args, **kwargs)
 
-    def apply_config(self, namespace, section, group, key, value) -> None:
+    def apply_config(
+        self,
+        namespace: argparse.Namespace,
+        section: str,
+        group: Optional[str],
+        key: str,
+        value: Any,
+    ) -> None:
         assert f'{section}/{key}' == self.config_key
         dest = self.argparse_dest()
 
@@ -1662,7 +1700,7 @@ CONFIG_ITEMS = [
 CONFIGFILE_ITEMS = {item.config_key: item for item in CONFIG_ITEMS if item.config_key}
 
 
-def apply_config(namespace, filename=None):
+def apply_config(namespace: argparse.Namespace, filename: Union[str, Path, None] = None) -> None:
     if filename is None:
         if namespace.config:
             # Config set by the user, use that.
@@ -1694,7 +1732,7 @@ def apply_config(namespace, filename=None):
         strict=False,
     )
     # Do not make keys lowercase
-    cp.optionxform = lambda option: option
+    cp.optionxform = lambda option: option  # type: ignore
 
     # The API is not great.
     read = cp.read(filename)
@@ -1718,8 +1756,8 @@ def apply_config(namespace, filename=None):
                 print(f'Unknown config setting [{section_name}] {key}=')
 
 
-def config_example():
-    prev_section = None
+def config_example() -> Iterator[str]:
+    prev_section: Optional[str] = None
     for item in CONFIG_ITEMS:
         section, key, value = item.config_example()
         if section:
@@ -1743,7 +1781,7 @@ class PagerHelpAction(argparse._HelpAction):  # pylint: disable=protected-access
         parser.exit()
 
 
-def create_parser():
+def create_parser() -> argparse.ArgumentParser:
     p = argparse.ArgumentParser(
         description='Build and sign Unified Kernel Images',
         usage='\n  '
@@ -1762,7 +1800,7 @@ def create_parser():
         item.add_to(p)
 
     # Suppress printing of usage synopsis on errors
-    p.error = lambda message: p.exit(2, f'{p.prog}: error: {message}\n')
+    p.error = lambda message: p.exit(2, f'{p.prog}: error: {message}\n')  # type: ignore
 
     # Make --help paged
     p.add_argument(
@@ -1774,7 +1812,7 @@ def create_parser():
     return p
 
 
-def finalize_options(opts):
+def finalize_options(opts: argparse.Namespace) -> None:
     # Figure out which syntax is being used, one of:
     # ukify verb --arg --arg --arg
     # ukify linux initrd…
@@ -1887,14 +1925,14 @@ def finalize_options(opts):
         sys.exit()
 
 
-def parse_args(args=None):
+def parse_args(args: Optional[list[str]] = None) -> argparse.Namespace:
     opts = create_parser().parse_args(args)
     apply_config(opts)
     finalize_options(opts)
     return opts
 
 
-def main():
+def main() -> None:
     opts = parse_args()
     if opts.verb == 'build':
         check_inputs(opts)