chuanqi/996box-decompiled/jsc-extract/probe-format.js

// 探针:0xa4 0x05 是不是某种压缩/编码 wrapper
const fs = require('fs');
const zlib = require('zlib');

const target = process.argv[2];
const raw = fs.readFileSync(target);
console.log('File:', target);
console.log('Size:', raw.length);
console.log('First 32 bytes:', raw.subarray(0, 32).toString('hex'));

// 1. 尝试 brotli 解压整段
try {
  const d = zlib.brotliDecompressSync(raw);
  console.log('[brotli full]: OK, decompressed to', d.length, 'bytes');
  console.log('  first 32:', d.subarray(0, 32).toString('hex'));
} catch (e) {
  console.log('[brotli full] FAIL:', e.message);
}

// 2. 尝试跳过前 N 字节 brotli 解压
for (let skip of [0, 1, 2, 4, 8]) {
  try {
    const d = zlib.brotliDecompressSync(raw.subarray(skip));
    console.log(`[brotli skip=${skip}]: OK, ${d.length} bytes, first 16: ${d.subarray(0, 16).toString('hex')}`);
  } catch (e) { /* skip */ }
}

// 3. 尝试 gzip 解压
for (let skip of [0, 2, 4]) {
  try {
    const d = zlib.gunzipSync(raw.subarray(skip));
    console.log(`[gzip skip=${skip}]: OK, ${d.length} bytes`);
  } catch (e) { /* skip */ }
}

// 4. 看 V8 字节码的 source hash (字节 8-12 LE) 是否合理
const MAGIC = Buffer.from([0xde, 0xc0]);
for (let off = 0; off < 6; off++) {
  if (raw.subarray(off + 2, off + 4).equals(MAGIC) || raw.subarray(off, off + 2).equals(MAGIC)) {
    console.log(`V8 magic at offset ${off}`);
    if (off + 12 <= raw.length) {
      const sourceHash = raw.readUInt32LE(off + 8);
      const flagHash = raw.readUInt32LE(off + 12);
      console.log(`  source hash (should be source length): ${sourceHash}`);
      console.log(`  flag hash: 0x${flagHash.toString(16)}`);
    }
  }
}