Question

为什么我向DeviceIoControl发送命令：

byte lpInBuffer[44] = { 0x2C, 0x00, 0x00, 0x00, 0x01... };
byte lpOutBuffer[88];

BOOL result = DeviceIoControl(open, 0x0004D004, lpInBuffer, sizeof(lpInBuffer), &lpOutBuffer, sizeof(lpOutBuffer), 0x00000000, 0x00000000);

err = GetLastError(); //
cout << "result:" << result << ", err: " << err << "\n";

结果还可以！

但如果我这样做，结果会出错：

void putMessage(HANDLE handle, int type, int output_len, byte message[]) {
    byte* lpOutBuffer = new byte[output_len];
    byte* lpInBuffer = message;

    for (int i = 0; i < sizeof(lpInBuffer); i++) {
        cout << lpInBuffer[i];
    }

    BOOL result = DeviceIoControl(handle, type, lpInBuffer, sizeof(lpInBuffer), &lpOutBuffer, sizeof(lpOutBuffer), 0x00000000, 0x00000000);


    int err = GetLastError();
    cout << "result:" << result << ", err: " << err << "\n";

    for (int i = 0; i < sizeof(lpOutBuffer); i++) {
        cout << lpOutBuffer[i];
    }

    cout << "\n\n";
}

putMessage(open, 0x0004D004, 88, new byte[44]{ 0x2C, 0x00, 0x00, 0x00, 0x01... });

Answer 1

在你的第一个代码示例中，你处理的是 array 类型的变量，而这种类型的sizeof是（已知的编译时间常数）大小以CHAR_BITS位的元素为单位。

在第二个代码示例中，您不处理数组类型的变量，而是处理指针类型的变量。指针的大小独立于它可能指向的数组的大小（可能在编译时未知）。

要解决此问题，您还需要将message大小传递给您的函数。在函数中使用该大小以及输出缓冲区大小而不是那些sizeof表达式。

Answer 2

此代码正常运行：

void putMessage(HANDLE handle, int type, int output_size, vector<byte> input) {
    vector<byte> output(output_size);

    cout << "lpInBuffer:" << input.size() << ", lpOutBuffer: " << output.size() << "\n";

    BOOL result = DeviceIoControl(handle, type, input.data(), input.size(), (void*)output.data(), output.size(), 0x00000000, 0x00000000);

    int err = GetLastError(); // 5 i.e. ERROR_ACCESS_DENIED
    cout << "result:" << result << ", err: " << err << "\n";


    for (int i = 0; i < output.size(); i++) {
        cout << hexToString(output[i]) << " ";
    }

    cout << "\n\n";
}

C ++把字节数组放到函数中

2 个答案: