Question

我的代码旨在将原始数据的前512个字节转储到驱动器中。 CreateFileW非常适合打开手柄，我已经通过获取驱动器几何体来测试它，所以我知道这不是问题所在。 ReadFileEx声称它正在工作，GetLastError返回0，但缓冲区保持为空并且没有数据被读取。这是我的代码：

#define UNICODE 1
#define _UNICODE 1

#include <windows.h>
#include <winioctl.h>
#include <stdio.h>
#include <tchar.h>
#include <strsafe.h>

#define wszDrive L"\\\\.\\X:"
#define BUFFERSIZE 512
DWORD g_BytesTransferred = 0;

VOID CALLBACK FileIOCompletionRoutine(
    __in  DWORD dwErrorCode,
    __in  DWORD dwNumberOfBytesTransfered,
    __in  LPOVERLAPPED lpOverlapped
);

VOID CALLBACK FileIOCompletionRoutine(
    __in  DWORD dwErrorCode,
    __in  DWORD dwNumberOfBytesTransfered,
    __in  LPOVERLAPPED lpOverlapped)
{
    _tprintf(TEXT("Error code:\t%x\n"), dwErrorCode);
    _tprintf(TEXT("Number of bytes:\t%x\n"), dwNumberOfBytesTransfered);
    g_BytesTransferred = dwNumberOfBytesTransfered;
}

HANDLE GetDriveHandle(LPWSTR wszPath)
{
    HANDLE hDevice = INVALID_HANDLE_VALUE;
    BOOL bResult = FALSE;
    DWORD junk = 0;

    hDevice = CreateFileW(wszPath,
        FILE_SHARE_READ | FILE_SHARE_WRITE,
        FILE_SHARE_READ |
        FILE_SHARE_WRITE,
        NULL,
        OPEN_EXISTING,
        0,
        NULL);

    return (hDevice);
}

int wmain(int argc, wchar_t *argv[])
{
    BOOL bResult = FALSE;
    ULONGLONG DiskSize = 0;
    char ReadBuffer[BUFFERSIZE] = { 0 };
    OVERLAPPED ol = { 0 };
    DWORD dwBytesRead = 0;

    HANDLE hDevice = GetDriveHandle(wszDrive);



    if (hDevice == INVALID_HANDLE_VALUE) {
        printf("Error Opening Drive");
    }
    else {
        printf("Drive Handle Opened. Starting Read.\n");
        ReadFileEx(hDevice, ReadBuffer, BUFFERSIZE, &ol, FileIOCompletionRoutine);
        if (dwBytesRead == 0) {
            printf("No Bytes Read. Error: %08x.\n", GetLastError());
        }
        ReadBuffer[dwBytesRead] = '\0';
        printf("%s", ReadBuffer);
    }

    CloseHandle(hDevice);

    while (true) {

    }

    return ((int)bResult);
}

Answer 1

关于输入句柄，ReadFileEx的文档说：

此参数可以是CreateFile函数使用FILE_FLAG_OVERLAPPED标志打开的任何句柄，也可以是套接字或接受函数返回的套接字句柄。

https://msdn.microsoft.com/en-us/library/windows/desktop/aa365468(v=vs.85).aspx

但你似乎没有使用那面旗帜。

它还声明：

此句柄还必须具有GENERIC_READ访问权限。有关访问权限的更多信息，请参阅文件安全性和访问权限。

ReadFileEx无法处理驱动器句柄，声称成功

1 个答案: