windows - 将 Windows 设备路径解析为驱动器号

Question

你如何解析一个 NT 风格的设备路径，例如\Device\CdRom0，到它的逻辑驱动器号，例如G:\？

编辑：卷名与设备路径不同，因此很遗憾GetVolumePathNamesForVolumeName()不起作用。

Answer 1

希望下面的代码足以解决这个问题——在你初始化它之后，你只需要遍历集合来找到你的匹配项。您可能希望在插入集合之前将所有内容转换为大写/小写，以帮助提高查找性能。

typedef basic_string<TCHAR> tstring;
typedef map<tstring, tstring> HardDiskCollection;

void Initialise( HardDiskCollection &_hardDiskCollection )
{
    TCHAR tszLinkName[MAX_PATH] = { 0 };
    TCHAR tszDevName[MAX_PATH] = { 0 };
    TCHAR tcDrive = 0;

    _tcscpy_s( tszLinkName, MAX_PATH, _T("a:") );
    for ( tcDrive = _T('a'); tcDrive < _T('z'); ++tcDrive )
    {
        tszLinkName[0] = tcDrive;
        if ( QueryDosDevice( tszLinkName, tszDevName, MAX_PATH ) )
        {
            _hardDiskCollection.insert( pair<tstring, tstring>( tszLinkName, tszDevName ) );
        }
    }
}

Answer 2

也许您可以使用 GetVolumeNameForMountPoint 并遍历所有挂载点 A:\ 到 Z:\，找到匹配项时中断？

http://msdn.microsoft.com/en-us/library/aa364994(VS.85).aspx

（这个我没试过）

Answer 3

以下函数仅使用 C 完成工作

BOOL GetWin32FileName(const TCHAR* pszNativeFileName, TCHAR *pszWin32FileName)
{
    BOOL bFound = FALSE;

    // Translate path with device name to drive letters.
    TCHAR szTemp[MAX_PATH];
    szTemp[0] = '\0';

    if (GetLogicalDriveStrings(MAX_PATH - 1, szTemp))
    {
        TCHAR szName[MAX_PATH];
        TCHAR szDrive[3] = TEXT(" :");
        TCHAR* p = szTemp;

        do
        {
            // Copy the drive letter to the template string
            *szDrive = *p;

            // Look up each device name
            if (QueryDosDevice(szDrive, szName, MAX_PATH))
            {
                size_t uNameLen = _tcslen(szName);

                if (uNameLen < MAX_PATH)
                {
                    bFound = _tcsnicmp(pszNativeFileName, szName, uNameLen) == 0
                        && *(pszNativeFileName + uNameLen) == _T('\\');

                    if (bFound)
                    {
                        // Replace device path with DOS path
                        StringCchPrintf(pszWin32FileName,
                            MAX_PATH,
                            TEXT("%s%s"),
                            szDrive,
                            pszNativeFileName + uNameLen);
                    }
                }
            }
            // Go to the next NULL character.
            while (*p++);
        } while (!bFound && *p);
    }

    return(bFound);
}

Answer 4

您可以查找所有卷的名称以匹配设备名称并获取驱动器号。这是一个示例：

int DeviceNameToVolumePathName(WCHAR *filepath) {
    WCHAR fileDevName[MAX_PATH];
    WCHAR devName[MAX_PATH];
    WCHAR fileName[MAX_PATH];
    HANDLE FindHandle = INVALID_HANDLE_VALUE;
    WCHAR  VolumeName[MAX_PATH];
    DWORD  Error = ERROR_SUCCESS;
    size_t Index = 0;
    DWORD  CharCount = MAX_PATH + 1;

    int index = 0;
    // \Device\HarddiskVolume1\windows,locate \windows.
    for (int i = 0; i < lstrlenW(filepath); i++) {
        if (!memcmp(&filepath[i], L"\\", 2)) {
            index++;
            if (index == 3) {
                index = i;
                break;
            }
        }
    }
    filepath[index] = L'\0';

    memcpy(fileDevName, filepath, (index + 1) * sizeof(WCHAR));

    FindHandle = FindFirstVolumeW(VolumeName, ARRAYSIZE(VolumeName));

    if (FindHandle == INVALID_HANDLE_VALUE)
    {
        Error = GetLastError();
        wprintf(L"FindFirstVolumeW failed with error code %d\n", Error);
        return FALSE;
    }
    for (;;)
    {
        //  Skip the \\?\ prefix and remove the trailing backslash.
        Index = wcslen(VolumeName) - 1;

        if (VolumeName[0] != L'\\' ||
            VolumeName[1] != L'\\' ||
            VolumeName[2] != L'?' ||
            VolumeName[3] != L'\\' ||
            VolumeName[Index] != L'\\')
        {
            Error = ERROR_BAD_PATHNAME;
            wprintf(L"FindFirstVolumeW/FindNextVolumeW returned a bad path: %s\n", VolumeName);
            break;
        }
        VolumeName[Index] = L'\0';
        CharCount = QueryDosDeviceW(&VolumeName[4], devName, 100);
        if (CharCount == 0)
        {
            Error = GetLastError();
            wprintf(L"QueryDosDeviceW failed with error code %d\n", Error);
            break;
        }
        if (!lstrcmpW(devName, filepath)) {
            VolumeName[Index] = L'\\';
            Error = GetVolumePathNamesForVolumeNameW(VolumeName, fileName, CharCount, &CharCount);
            if (!Error) {
                Error = GetLastError();
                wprintf(L"GetVolumePathNamesForVolumeNameW failed with error code %d\n", Error);
                break;
            }

            // concat drive letter to path
            lstrcatW(fileName, &filepath[index + 1]);
            lstrcpyW(filepath, fileName);

            Error = ERROR_SUCCESS;
            break;
        }

        Error = FindNextVolumeW(FindHandle, VolumeName, ARRAYSIZE(VolumeName));

        if (!Error)
        {
            Error = GetLastError();

            if (Error != ERROR_NO_MORE_FILES)
            {
                wprintf(L"FindNextVolumeW failed with error code %d\n", Error);
                break;
            }

            //
            //  Finished iterating
            //  through all the volumes.
            Error = ERROR_BAD_PATHNAME;
            break;
        }
    }

    FindVolumeClose(FindHandle);
    if (Error != ERROR_SUCCESS)
        return FALSE;
    return TRUE;

}

如果您想在驱动程序中解决它，您可以查看此链接以供参考。

Answer 5

这是解决方案的重构版本。

我用 wchar_t 替换了 TChAR，因为在大多数项目中使用它并不是一个好主意。

std::map<std::wstring, std::wstring> GetDosPathDevicePathMap()
{
    // It's not really related to MAX_PATH, but I guess it should be enough.
    // Though the docs say "The first null-terminated string stored into the buffer is the current mapping for the device.
    //                      The other null-terminated strings represent undeleted prior mappings for the device."
    wchar_t devicePath[MAX_PATH] = { 0 };
    std::map<std::wstring, std::wstring> result;
    std::wstring dosPath = L"A:";

    for (wchar_t letter = L'A'; letter <= L'Z'; ++letter)
    {
        dosPath[0] = letter;
        if (QueryDosDeviceW(dosPath.c_str(), devicePath, MAX_PATH)) // may want to properly handle errors instead ... e.g. check ERROR_INSUFFICIENT_BUFFER
        {
            result[dosPath] = devicePath;
        }
    }
    return result;
}