From: Jamey Kirby [jkirby@storagecraft.com]
Sent: Thursday, January 24, 2002 12:45 PM
To: NT Developers Interest List
Subject: [ntdev] Re: Unloading a RAM Disk driver

Yes, this works fine on read-only media.

-----Original Message-----
From: bounce-ntdev-562@lists.osr.com
[mailto:bounce-ntdev-562@lists.osr.com] On Behalf Of Anton Kolomyeytsev
Sent: Thursday, January 24, 2002 5:55 AM
To: NT Developers Interest List
Subject: [ntdev] Re: Unloading a RAM Disk driver


Hi,

Check this out...

Regards,
Anton

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

   // Prototypes

   BOOL EjectVolume(TCHAR cDriveLetter);

   HANDLE OpenVolume(TCHAR cDriveLetter);
   BOOL LockVolume(HANDLE hVolume);
   BOOL DismountVolume(HANDLE hVolume);
   BOOL PreventRemovalOfVolume(HANDLE hVolume, BOOL fPrevent);
   BOOL AutoEjectVolume(HANDLE hVolume);
   BOOL CloseVolume(HANDLE hVolume);

   LPTSTR szVolumeFormat = TEXT("\\\\.\\%c:");
   LPTSTR szRootFormat = TEXT("%c:\\");
   LPTSTR szErrorFormat = TEXT("Error %d: %s\n");

   void ReportError(LPTSTR szMsg)
   {
       _tprintf(szErrorFormat, GetLastError(), szMsg);
   }

   HANDLE OpenVolume(TCHAR cDriveLetter)
   {
       HANDLE hVolume;
       UINT uDriveType;
       TCHAR szVolumeName[8];
       TCHAR szRootName[5];
       DWORD dwAccessFlags;

       wsprintf(szRootName, szRootFormat, cDriveLetter);

       uDriveType = GetDriveType(szRootName);
       switch(uDriveType) {
       case DRIVE_REMOVABLE:
           dwAccessFlags = GENERIC_READ | GENERIC_WRITE;
           break;
       case DRIVE_CDROM:
           dwAccessFlags = GENERIC_READ;
           break;
       default:
           _tprintf(TEXT("Cannot eject.  Drive type is incorrect.\n"));
           return INVALID_HANDLE_VALUE;
       }

       wsprintf(szVolumeName, szVolumeFormat, cDriveLetter);

       hVolume = CreateFile(   szVolumeName,
                               dwAccessFlags,
                               FILE_SHARE_READ | FILE_SHARE_WRITE,
                               NULL,
                               OPEN_EXISTING,
                               0,
                               NULL );
       if (hVolume == INVALID_HANDLE_VALUE)
           ReportError(TEXT("CreateFile"));

       return hVolume;
   }

   BOOL CloseVolume(HANDLE hVolume)
   {
       return CloseHandle(hVolume);
   }

   #define LOCK_TIMEOUT        10000       // 10 Seconds
   #define LOCK_RETRIES        20

   BOOL LockVolume(HANDLE hVolume)
   {
       DWORD dwBytesReturned;
       DWORD dwSleepAmount;
       int nTryCount;

       dwSleepAmount = LOCK_TIMEOUT / LOCK_RETRIES;

       // Do this in a loop until a timeout period has expired
       for (nTryCount = 0; nTryCount < LOCK_RETRIES; nTryCount++) {
           if (DeviceIoControl(hVolume,
                               FSCTL_LOCK_VOLUME,
                               NULL, 0,
                               NULL, 0,
                               &dwBytesReturned,
                               NULL))
               return TRUE;

           Sleep(dwSleepAmount);
       }

       return FALSE;
   }

   BOOL DismountVolume(HANDLE hVolume)
   {
       DWORD dwBytesReturned;

       return DeviceIoControl( hVolume,
                               FSCTL_DISMOUNT_VOLUME,
                               NULL, 0,
                               NULL, 0,
                               &dwBytesReturned,
                               NULL);
   }

   BOOL PreventRemovalOfVolume(HANDLE hVolume, BOOL fPreventRemoval)
   {
       DWORD dwBytesReturned;
       PREVENT_MEDIA_REMOVAL PMRBuffer;

       PMRBuffer.PreventMediaRemoval = fPreventRemoval;

       return DeviceIoControl( hVolume,
                               IOCTL_STORAGE_MEDIA_REMOVAL,
                               &PMRBuffer,
sizeof(PREVENT_MEDIA_REMOVAL),
                               NULL, 0,
                               &dwBytesReturned,
                               NULL);
   }

   AutoEjectVolume(HANDLE hVolume)
   {
       DWORD dwBytesReturned;

       return DeviceIoControl( hVolume,
                               IOCTL_STORAGE_EJECT_MEDIA,
                               NULL, 0,
                               NULL, 0,
                               &dwBytesReturned,
                               NULL);
   }

   BOOL EjectVolume(TCHAR cDriveLetter)
   {
       HANDLE hVolume;

       BOOL fRemoveSafely = FALSE;
       BOOL fAutoEject = FALSE;

       // Open the volume.
       hVolume = OpenVolume(cDriveLetter);
       if (hVolume == INVALID_HANDLE_VALUE)
           return FALSE;

       // Lock and dismount the volume.
       if (LockVolume(hVolume) && DismountVolume(hVolume)) {
           fRemoveSafely = TRUE;

           // Set prevent removal to false and eject the volume.
           if (PreventRemovalOfVolume(hVolume, FALSE) &&
               AutoEjectVolume(hVolume))
               fAutoEject = TRUE;
       }

       // Close the volume so other processes can use the drive.
       if (!CloseVolume(hVolume))
           return FALSE;

       if (fAutoEject)
           printf("Media in Drive %c has been ejected safely.\n",
                  cDriveLetter);
       else {
           if (fRemoveSafely)
               printf("Media in Drive %c can be safely removed.\n",
               cDriveLetter);
       }

       return TRUE;
   }

   void Usage()
   {
       printf("Usage: Eject <drive letter>\n\n");
       return ;
   }

   void main(int argc, char * argv[])
   {
       if (argc != 2) {
           Usage();
           return ;
       }

       if (!EjectVolume(argv[1][0]))
           printf("Failure ejecting drive %c.\n", argv[1][0]);

       return ;
   }


On 01/23/02, ""Andreas Roth" <aroth@arsoft-online.de>" wrote:
> Hello!
> 
> To change the settings for my RAM Disk driver it is necessary to 
> restart the driver. I have added an Unload Handler to my driver. 
> Removing/Restarting the driver works if no File System driver is 
> attached to it (when no file system is on the disk). But when a File 
> System driver is attached to the driver the system does not allow to 
> stop/unload the driver ?
> 
> How can a detach the File System driver from the RAM Disk driver, so 
> that i can stop/unload the RAM Disk driver ?
> 
> A. Roth
> 
> 
> ---
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