run

#!/usr/bin/python3 -u

import os
import sys
import random
import subprocess
import string

def random_string(n):
    return ''.join(random.choice(string.ascii_lowercase) for _ in range(n))

def check_pow(bits):
    r = random_string(10)
    print(f"hashcash -mb{bits} {r}")
    solution = input("Solution:").strip()
    if subprocess.call(["hashcash", f"-cdb{bits}", "-r", r, solution],
                       cwd="/tmp",
                       stdout=subprocess.DEVNULL,
                       stderr=subprocess.DEVNULL) != 0:
        raise Exception("Invalid PoW")

POW_BITS = 25

def main():
    check_pow(POW_BITS)
    fsize = int(input("Size of initramfs in bytes: "))

    MAX_SIZE = 10 * 1024 * 1024
    data = sys.stdin.buffer.read(fsize)[:MAX_SIZE]
    print(f"Read {len(data)} bytes")

    with open("/tmp/initramfs.cpio.gz", "wb") as initramfs:
        initramfs.write(data)

    os.execvp("qemu-system-x86_64",
              ["qemu-system-x86_64",
              "-kernel", "./bzImage",
              "-initrd", "/tmp/initramfs.cpio.gz",
              "-cdrom", "./secrets.iso",
              "-enable-kvm",
              "-m", "64m",
              "-nographic",
              "-append", "console=ttyS0",
              "-monitor", "/dev/null"]
            )

if __name__ == "__main__":
    main()