Files
ha-ninlight/custom_components/ninlight/firmware.py
T

197 lines
7.1 KiB
Python

"""Firmware images for ninlight lamps: trailer, version order, Wi-Fi check, catalog.
Deliberately free of Home Assistant imports. Blocking functions are marked; callers run them in an
executor. Facts behind the constants: spec §2 (layout checked against a real image).
"""
from __future__ import annotations
from dataclasses import dataclass
import hashlib
import logging
from pathlib import Path
import re
import zlib
_LOGGER = logging.getLogger(__name__)
TRAILER_SIZE = 512
TRAILER_MAGIC = b"NINL"
TRAILER_FORMAT = 1
W600_HEADER_SIZE = 56
GZIP_MAGIC = b"\x1f\x8b\x08"
# cmake/write_version.cmake cuts the version hard to 15 characters.
VERSION_FIELD_MAX = 15
_VERSION_RE = re.compile(
r"^(?P<major>\d+)\.(?P<minor>\d+)\.(?P<patch>\d+)"
r"(?:-rc(?P<rc>\d+))?"
r"(?:-(?P<commits>\d+)(?P<hash>-g[0-9a-f]*)?)?"
r"(?:-d(?:i(?:r(?:t(?:y)?)?)?)?)?$"
)
class InvalidImageError(ValueError):
"""The file is not a valid ninlight OTA image."""
@dataclass(frozen=True, slots=True)
class FirmwareVersion:
"""A parsed `git describe` version. The hash is ignored on purpose (usually truncated)."""
base: tuple[int, int, int]
rc: int | None
commits: int
@property
def sort_key(self) -> tuple[int, int, int, int, int, int]:
# A release candidate sorts before the release of the same base.
rc_rank, rc_number = (0, self.rc) if self.rc is not None else (1, 0)
return (*self.base, rc_rank, rc_number, self.commits)
def parse_version(text: str) -> FirmwareVersion | None:
match = _VERSION_RE.match(text)
if match is None:
return None
if len(text) == VERSION_FIELD_MAX and text[-1].isdigit() and match["hash"] is None:
# The cut may have landed inside the commit (or rc) number: not comparable.
return None
return FirmwareVersion(
(int(match["major"]), int(match["minor"]), int(match["patch"])),
int(match["rc"]) if match["rc"] is not None else None,
int(match["commits"]) if match["commits"] is not None else 0,
)
def is_newer(candidate: str, installed: str) -> bool:
new, old = parse_version(candidate), parse_version(installed)
if new is None or old is None:
return False
return new.sort_key > old.sort_key
def parse_trailer(data: bytes) -> tuple[str, str]:
"""Return (device_type, version) of a valid image or raise InvalidImageError."""
if len(data) <= TRAILER_SIZE:
raise InvalidImageError("too short for a trailer")
payload, trailer = data[:-TRAILER_SIZE], data[-TRAILER_SIZE:]
if trailer[0:4] != TRAILER_MAGIC:
raise InvalidImageError("no NINL trailer")
if trailer[4] != TRAILER_FORMAT:
raise InvalidImageError(f"unsupported trailer format {trailer[4]}")
if trailer[37:69] != hashlib.sha256(payload).digest():
raise InvalidImageError("sha256 mismatch")
device_type = _text_field(trailer[5:21])
version = _text_field(trailer[21:37])
if not device_type or not version:
raise InvalidImageError("empty device type or version")
return device_type, version
def _text_field(raw: bytes) -> str:
return raw.split(b"\x00", 1)[0].decode("ascii", errors="replace")
def contains_ssid(data: bytes, ssid: str) -> bool:
"""True if the decompressed firmware carries `ssid` as a NUL-framed C string (spec §7)."""
if not ssid or len(data) <= TRAILER_SIZE:
return False
payload = data[:-TRAILER_SIZE]
start = payload.find(GZIP_MAGIC, W600_HEADER_SIZE)
if start < 0:
return False
try:
raw = zlib.decompressobj(31).decompress(payload[start:])
except zlib.error:
return False
return b"\x00" + ssid.encode() + b"\x00" in raw
@dataclass(frozen=True, slots=True)
class FirmwareImage:
"""One valid image in the firmware folder."""
path: Path
device_type: str
version: str
size: int
mtime_ns: int
def _sort_key(image: FirmwareImage) -> tuple[int, ...]:
version = parse_version(image.version)
return version.sort_key if version is not None else ()
class FirmwareCatalog:
"""All valid images in one folder. Not thread-safe: callers serialize scans."""
def __init__(self, directory: Path) -> None:
self.directory = directory
self.images: tuple[FirmwareImage, ...] = ()
self._parsed: dict[tuple[str, int, int], FirmwareImage | None] = {}
self._ssid_hits: dict[tuple[str, int, int, str], bool] = {}
def scan(self) -> tuple[FirmwareImage, ...]:
"""Blocking. Invalid files are logged once per (path, mtime, size)."""
self.directory.mkdir(parents=True, exist_ok=True)
found: list[FirmwareImage] = []
seen: set[tuple[str, int, int]] = set()
for path in sorted(self.directory.glob("*.img")):
try:
if not path.is_file():
continue
stat = path.stat()
except OSError:
continue
key = (str(path), stat.st_mtime_ns, stat.st_size)
seen.add(key)
if key not in self._parsed:
try:
device_type, version = parse_trailer(path.read_bytes())
except (OSError, InvalidImageError) as err:
_LOGGER.warning("Ignoring firmware file %s: %s", path.name, err)
self._parsed[key] = None
else:
self._parsed[key] = FirmwareImage(
path, device_type, version, stat.st_size, stat.st_mtime_ns
)
image = self._parsed[key]
if image is not None:
found.append(image)
self._parsed = {k: v for k, v in self._parsed.items() if k in seen}
self._ssid_hits = {k: v for k, v in self._ssid_hits.items() if k[:3] in seen}
self.images = tuple(found)
return self.images
def newer_images(self, device_type: str, installed: str) -> list[FirmwareImage]:
"""Images for exactly this device type that are newer than `installed`, newest first."""
candidates = [
image
for image in self.images
if image.device_type == device_type and is_newer(image.version, installed)
]
return sorted(candidates, key=_sort_key, reverse=True)
def verify(self, image: FirmwareImage) -> bool:
"""Blocking. The file is still there, unchanged and valid for the same type/version."""
try:
stat = image.path.stat()
if (stat.st_mtime_ns, stat.st_size) != (image.mtime_ns, image.size):
return False
return parse_trailer(image.path.read_bytes()) == (image.device_type, image.version)
except OSError, InvalidImageError:
return False
def contains_ssid(self, image: FirmwareImage, ssid: str) -> bool:
"""Blocking, cached per (image file, ssid)."""
key = (str(image.path), image.mtime_ns, image.size, ssid)
if key not in self._ssid_hits:
try:
data = image.path.read_bytes()
except OSError:
return False
self._ssid_hits[key] = contains_ssid(data, ssid)
return self._ssid_hits[key]