查找分区的起始偏移量

如何解决查找分区的起始偏移量

假设我有一个带有两个分区e：，f：的USB驱动器。我怎么知道分区e：或f：从哪个偏移量开始，以便我可以从该偏移量开始写入原始数据。我找不到任何可以为我提供c ++偏移量的函数。在Dos中，我可以轻松地通过wmic partition get Index,Name,StartingOffset来实现这一点。

解决方法

要获取物理驱动器中的StartingOffset个分区（例如\\\\.\\PhysicalDrive1），可以使用IOCTL_DISK_GET_DRIVE_LAYOUT_EX获取每个分区的PARTITION_INFORMATION_EX阵列：

#include <windows.h>
#include <stdio.h>

#define wszDrive L"\\\\.\\PhysicalDrive1"

int wmain(int argc,wchar_t* argv[])
{

    HANDLE hDevice = INVALID_HANDLE_VALUE;  // handle to the drive to be examined 
    BOOL bResult = FALSE;                 // results flag
    DWORD junk = 0;                     // discard results
    DWORD error;

    DWORD szNewLayout = sizeof(DRIVE_LAYOUT_INFORMATION_EX) + sizeof(PARTITION_INFORMATION_EX) * 4 * 25;
    
    
    hDevice = CreateFileW(wszDrive,// drive to open
        GENERIC_READ,// no access to the drive
        FILE_SHARE_READ,NULL,// default security attributes
        OPEN_EXISTING,// disposition
        0,// file attributes
        0);            // do not copy file attributes
    if (hDevice == INVALID_HANDLE_VALUE)    // cannot open the drive
    {
        error = GetLastError();
        printf("CreateFileW error: %d\n",error);
        return -1;
    }

    DRIVE_LAYOUT_INFORMATION_EX* pdg = (DRIVE_LAYOUT_INFORMATION_EX*)malloc(szNewLayout);
    if (pdg == NULL)
    {
        error = GetLastError();
        printf("malloc error: %d\n",error);
        CloseHandle(hDevice);
        return -1;
    }
    ZeroMemory(pdg,szNewLayout);

    bResult = DeviceIoControl(hDevice,// device to be queried
        IOCTL_DISK_GET_DRIVE_LAYOUT_EX,// operation to perform
        NULL,// no input buffer
        pdg,szNewLayout,// sizeof(*pdg)*2,// output buffer
        &junk,// # bytes returned
        (LPOVERLAPPED)NULL);          // synchronous I/O
    if (!bResult)
    {
        error = GetLastError();
        printf("DeviceIoControl error: %d\n",error);
        free(pdg);
        CloseHandle(hDevice);
        return -1;
    }
    for (int i = 0; i < pdg->PartitionCount; i++) {
        printf("partition %d: %lld\n",i,pdg->PartitionEntry[i].StartingOffset.QuadPart);
    }

    free(pdg);
    CloseHandle(hDevice);
    return 0;
}

要获取指定分区（例如StartingOffset）的\\\\.\\E:，可以使用IOCTL_DISK_GET_PARTITION_INFO_EX：

#include <windows.h>
#include <stdio.h>

#define wszDrive L"\\\\.\\E:"

int wmain(int argc,wchar_t* argv[])
{
    HANDLE hDevice = INVALID_HANDLE_VALUE;  // handle to the drive to be examined 
    BOOL bResult = FALSE;                 // results flag
    DWORD junk = 0;                     // discard results
    DWORD error;

    PARTITION_INFORMATION_EX piex;
    ZeroMemory(&piex,sizeof(PARTITION_INFORMATION_EX));
    hDevice = CreateFileW(wszDrive,error);
        return -1;
    }

    bResult = DeviceIoControl(hDevice,IOCTL_DISK_GET_PARTITION_INFO_EX,&piex,sizeof(PARTITION_INFORMATION_EX),&junk,(LPOVERLAPPED)NULL);
    if (!bResult)
    {
        error = GetLastError();
        printf("DeviceIoControl error: %d\n",error);
        CloseHandle(hDevice);
        return -1;
    }
    wprintf(L"%s StartingOffset: %lld\n",wszDrive,piex.StartingOffset.QuadPart);

    CloseHandle(hDevice);
    return 0;
}