mapping partitions starting from PhysicalDrive

Question

I want to map all partitions from all drives in Windows (the ones who are not mapped already). I mean I want to assign to each of them drive letters. I know that you can do it with FindFirstVolume, FindNextVolume, FindVolumeClose but there are situations where you can't use them. I tried with QueryDosDevice, same thing.

The idea is to start from \.\PhysicalDrive[n], find out the partitions and map them. I know it's doable because I saw a program that can do that. But I don't like it, because it maps hidden partitions also.

Does someone know a way...? Thank you.

Answer 1

I did it :) I made a program who adds or removes drive letters when it's started - if one or more storage drives were added or removed from the computer:

program MapDrives;

uses Windows;

type
   TPARTITION_INFORMATION = record
      StartingOffset: _LARGE_INTEGER; //TLargeInteger;
      PartitionLength: _LARGE_INTEGER; //TLargeInteger;
      HiddenSectors: DWORD;
      PartitionNumber: DWORD;
      PartitionType: BYTE;
      BootIndicator: BOOLEAN;
      RecognizedPartition: BOOLEAN;
      RewritePartition: BOOLEAN;
   end;

function IntToStr(Value: Integer): string;
begin
   if Value < 10 then
      Result := Char(Value + 48)
   else
      Result := Char(Value div 10 + 48) + Char(Value + 48);
end;

function GetNextAvailableLetter: AnsiChar;
var Drives, mask: DWord;
   i: Integer;
begin
   Drives := GetLogicalDrives;
   mask := 4;
   Result := 'Z';
   for i := 3 to 26 do //C to Z
   begin
      if mask and Drives = 0 then
      begin
         Result := AnsiChar(64 + i);
         Exit;
      end;
      mask := mask shl 1;
   end;
end;


const IOCTL_DISK_GET_PARTITION_INFO = $0074004;

var i, j, k: Integer;
   H: THandle;
   dwBytesReturned: DWORD;
   BreakCycle, DoMount: Boolean;
   NextLetter: AnsiChar;
   PartitionInformation: TPARTITION_INFORMATION;
   PartitionsInformation: array of TPARTITION_INFORMATION;
   Drives, mask: DWord;
   OldMode: UINT;

begin
   OldMode := SetErrorMode(SEM_FAILCRITICALERRORS); //so it shouldn't ask to insert CD or card

   //gets informations about already mounted partitions
   SetLength(PartitionsInformation, 0);
   Drives := GetLogicalDrives;
   mask := 4;
   for i := 3 to 26 do //C to Z
   begin
      if mask and Drives <> 0 then
      begin
         H := CreateFile(PAnsiChar('\\.\' + Char(64 + i) + ':'), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, 0, 0);
         if H <> INVALID_HANDLE_VALUE then
         begin
            SetLength(PartitionsInformation, Length(PartitionsInformation) + 1);
            DeviceIoControl(H, IOCTL_DISK_GET_PARTITION_INFO, nil, 0, @PartitionsInformation[High(PartitionsInformation)], SizeOf(TPARTITION_INFORMATION), dwBytesReturned, nil);
            CloseHandle(H);
         end
         else     //removes unaccessible drives
            DefineDosDevice(DDD_REMOVE_DEFINITION or DDD_RAW_TARGET_PATH, PAnsiChar(string(Char(64 + i) + ':')), nil);
      end;
      mask := mask shl 1;
   end;

   for i := 0 to 99 do
   begin
      H := CreateFile(PAnsiChar('\\.\PhysicalDrive' + IntToStr(i)), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, 0, 0);
      if H = INVALID_HANDLE_VALUE then //no more hdd's
         Break;
      CloseHandle(H);
      for j := 1 to 20 do
      begin
         BreakCycle := False;
         NextLetter := GetNextAvailableLetter;
         DefineDosDevice(DDD_RAW_TARGET_PATH or DDD_NO_BROADCAST_SYSTEM, PAnsiChar(string(NextLetter + ':')), PAnsiChar('\Device\Harddisk' + IntToStr(i) + '\Partition' + IntToStr(j)));
         DoMount := True;
         H := CreateFile(PAnsiChar('\\.\' + NextLetter + ':'), GENERIC_READ, FILE_SHARE_READ or FILE_SHARE_WRITE, nil, OPEN_EXISTING, 0, 0);
         if H = INVALID_HANDLE_VALUE then //no more partitions
            BreakCycle := True
         else
         begin
            PartitionInformation.PartitionType := 0;
            DeviceIoControl(H, IOCTL_DISK_GET_PARTITION_INFO, nil, 0, @PartitionInformation, SizeOf(TPARTITION_INFORMATION), dwBytesReturned, nil);
            DoMount := PartitionInformation.PartitionType in [0, 1, 6, 7, 11, 12, 114];
            CloseHandle(H);
         end;
         if DoMount then
         begin
            for k := 0 to High(PartitionsInformation) do  //compare with already mounted partitions
               if (PartitionsInformation[k].StartingOffset.LowPart = PartitionInformation.StartingOffset.LowPart) and
                  (PartitionsInformation[k].StartingOffset.HighPart = PartitionInformation.StartingOffset.HighPart) and
                  (PartitionsInformation[k].StartingOffset.QuadPart = PartitionInformation.StartingOffset.QuadPart) and
                  (PartitionsInformation[k].PartitionLength.LowPart = PartitionInformation.PartitionLength.LowPart) and
                  (PartitionsInformation[k].PartitionLength.HighPart = PartitionInformation.PartitionLength.HighPart) and
                  (PartitionsInformation[k].PartitionLength.QuadPart = PartitionInformation.PartitionLength.QuadPart) and
                  (PartitionsInformation[k].HiddenSectors = PartitionInformation.HiddenSectors) and
                  (PartitionsInformation[k].PartitionType = PartitionInformation.PartitionType) and
                  (PartitionsInformation[k].BootIndicator = PartitionInformation.BootIndicator) and
                  (PartitionsInformation[k].RecognizedPartition = PartitionInformation.RecognizedPartition) then
                  Break;
            DoMount := k > High(PartitionsInformation);
         end;
         DefineDosDevice(DDD_REMOVE_DEFINITION or DDD_RAW_TARGET_PATH, PAnsiChar(string(NextLetter + ':')), nil);
         if (not BreakCycle) and DoMount then
            DefineDosDevice(DDD_RAW_TARGET_PATH, PAnsiChar(string(NextLetter + ':')), PAnsiChar('\Device\Harddisk' + IntToStr(i) + '\Partition' + IntToStr(j)));
         if BreakCycle then
            Break;
      end;
   end;
   SetErrorMode(OldMode); //restore original mode
end.

On the computers that I mentioned it works perfectly.

Thank you guys for all your ideas which helped me to make this code.

If someone notice some bugs or has any good ideas about how to improve it, I'll be glad to fix/implement them.