Handle CRC too short in readMemory

2022-01-26 21:01:55 +01:00 · 2022-01-26 21:01:55 +01:00 · efddfd60cb
parent 00fb5f1dee
commit efddfd60cb
1 changed files with 5 additions and 1 deletions
--- a/solar_ble.py
+++ b/solar_ble.py
@ -305,7 +305,11 @@ def readMemory(fh: RawIOBase, address: int, words: int = 1) -> Optional[bytes]:
        data = fh.read(size)
        _crc = fh.read(2)
        if data and _crc:
-            crc = struct.unpack_from("<H", _crc)[0]
+            try:
+                crc = struct.unpack_from("<H", _crc)[0]
+            except struct.error:
+                log(f"readMemory: CRC error; read {len(_crc)} bytes (2 expected)")
+                return None
            calculated_crc = modbus(bytes([tag, operation, size, *data]))
            if crc == calculated_crc:
                return data