get raspberry PI temperature straight from /dev/vcio

temp.py

import os
import struct
import fcntl
from decimal import Decimal

DEVICE_FILE_NAME = "/dev/vcio"
IOCTL_MBOX_PROPERTY = 0xC0046400  # _IOWR(MAJOR_NUM, 0, char *) adjusted for alignment
GET_GENCMD_RESULT = 0x00030080
MAX_STRING = 1024

def mbox_open():
    try:
        file_desc = os.open(DEVICE_FILE_NAME, os.O_RDWR)
        return file_desc
    except OSError as e:
        raise RuntimeError(f"Failed to open device file {DEVICE_FILE_NAME}: {e}")

def mbox_close(file_desc):
    os.close(file_desc)

def mbox_property(file_desc, buf):
    mutable_buf = bytearray(struct.pack(f"{len(buf)}I", *buf))
    try:
        fcntl.ioctl(file_desc, IOCTL_MBOX_PROPERTY, mutable_buf)
    except OSError as e:
        print(f"[ERROR] ioctl failed: {e}")
        raise

    return struct.unpack(f"{len(buf)}I", mutable_buf)

def gencmd(file_desc, command):
    command = command.encode('ascii') + b'\x00'  # Null-terminate the command

    buf = [
        0,                  # size (will be set later)
        0x00000000,         # process request
        GET_GENCMD_RESULT,  # tag id
        MAX_STRING,         # buffer length
        0,                  # request length (response will overwrite)
        0,                  # error response
    ]

    command_padded = command.ljust(MAX_STRING, b'\x00')
    buf += list(struct.unpack(f"{MAX_STRING // 4}I", command_padded))
    buf.append(0x00000000)  # End tag
    buf[0] = len(buf) * 4  # Set actual size in bytes

    response = mbox_property(file_desc, buf)
    temp_data_parts = (struct.pack('I', response[7]) + struct.pack('I', response[8])).decode('ascii')
    return  Decimal(temp_data_parts[1:-3])

def measure_temp():
    file_desc = mbox_open()
    try:
        return  gencmd(file_desc, "measure_temp")
    finally:
        mbox_close(file_desc)

# Example usage
if __name__ == "__main__":
    temp = measure_temp()
    print(temp)