Michael Sauer
76b9c3fef1
feat: nl_mkimage.py implementieren (Gegenstück zu nl_fwup_trailer.c aus Task 2)
49 lines
1.7 KiB
Python
Executable File
49 lines
1.7 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Appends the ninlight OTA trailer to a `_gz.img` produced by wm_tool.
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Layout (512 bytes): "NINL" | version(1) | device[16] | fw_version[16] | sha256[32] | 0xFF padding.
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The hash covers the complete `_gz.img` (T_BOOTER header + payload), which is exactly what the
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firmware hashes while writing the image to flash.
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"""
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import argparse
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import hashlib
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import sys
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from pathlib import Path
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TRAILER_SIZE = 512
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TRAILER_VERSION = 1
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FIELD = 16
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def field(value: str, name: str) -> bytes:
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raw = value.encode()
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if len(raw) >= FIELD:
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sys.exit(f"error: {name} '{value}' is too long (max {FIELD - 1} bytes)")
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return raw.ljust(FIELD, b"\x00")
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def main() -> None:
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p = argparse.ArgumentParser(description="append the ninlight OTA trailer")
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p.add_argument("--image", required=True, type=Path, help="input _gz.img")
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p.add_argument("--device", required=True, help="device id, e.g. e27_rgb")
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p.add_argument("--version", required=True, help="firmware version")
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p.add_argument("--out", required=True, type=Path, help="output _ota.img")
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a = p.parse_args()
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data = a.image.read_bytes()
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if len(data) > TRAILER_SIZE and data[-TRAILER_SIZE : -TRAILER_SIZE + 4] == b"NINL":
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sys.exit("error: image already carries a trailer")
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trailer = bytearray(b"\xff" * TRAILER_SIZE)
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trailer[0:4] = b"NINL"
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trailer[4] = TRAILER_VERSION
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trailer[5:21] = field(a.device, "device")
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trailer[21:37] = field(a.version, "version")
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trailer[37:69] = hashlib.sha256(data).digest()
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a.out.write_bytes(data + bytes(trailer))
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print(f"{a.out} ({len(data) + TRAILER_SIZE} bytes, device={a.device}, version={a.version})")
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if __name__ == "__main__":
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main()
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