对于项目,我想获取NTFS分区上所有空闲/已使用集群的列表。 为此,我必须转储$ Bitmap文件并解析其内容。
网上有很少的API和示例,但是它们似乎不起作用。是否有一个简单的方法/代码示例只是复制$ Bitmap文件。
使用FSCTL_GET_VOLUME_BITMAP是唯一的方法吗?理想情况下,我想在C#中完成。
答案 0 :(得分:1)
NFI.EXE(曾经是)“oem支持工具”的一部分可以枚举所有NTFS分区项。它也可能能够转储$ Bitmap的内容。
答案 1 :(得分:0)
你肯定想走简单路线并使用IOCTL,而不是试图直接阅读$Bitmap
。当然,如果有人为你做了,你不必亲自去做。事实证明,MSDN博主已经为您编写了一个不错的小包装器:
http://blogs.msdn.com/b/jeffrey_wall/archive/2004/09/13/229137.aspx
整个类有超过300行代码,所以我不会发布所有内容,但这里是获取卷位图的函数:
/// <summary>
/// Get cluster usage for a device
/// </summary>
/// <param name="DeviceName">use "c:"</param>
/// <returns>a bitarray for each cluster</returns>
static public BitArray GetVolumeMap(string DeviceName)
{
IntPtr pAlloc = IntPtr.Zero;
IntPtr hDevice = IntPtr.Zero;
try
{
hDevice = OpenVolume(DeviceName);
Int64 i64 = 0;
GCHandle handle = GCHandle.Alloc(i64, GCHandleType.Pinned);
IntPtr p = handle.AddrOfPinnedObject();
// alloc off more than enough for my machine
// 64 megs == 67108864 bytes == 536870912 bits == cluster count
// NTFS 4k clusters == 2147483648 k of storage == 2097152 megs == 2048 gig disk storage
uint q = 1024 * 1024 * 64; // 1024 bytes == 1k * 1024 == 1 meg * 64 == 64 megs
uint size = 0;
pAlloc = Marshal.AllocHGlobal((int)q);
IntPtr pDest = pAlloc;
bool fResult = DeviceIoControl(
hDevice,
FSConstants.FSCTL_GET_VOLUME_BITMAP,
p,
(uint)Marshal.SizeOf(i64),
pDest,
q,
ref size,
IntPtr.Zero);
if (!fResult)
{
throw new Exception(Marshal.GetLastWin32Error().ToString());
}
handle.Free();
/*
object returned was...
typedef struct
{
LARGE_INTEGER StartingLcn;
LARGE_INTEGER BitmapSize;
BYTE Buffer[1];
} VOLUME_BITMAP_BUFFER, *PVOLUME_BITMAP_BUFFER;
*/
Int64 StartingLcn = (Int64)Marshal.PtrToStructure(pDest, typeof(Int64));
Debug.Assert(StartingLcn == 0);
pDest = (IntPtr)((Int64)pDest + 8);
Int64 BitmapSize = (Int64)Marshal.PtrToStructure(pDest, typeof(Int64));
Int32 byteSize = (int)(BitmapSize / 8);
byteSize++; // round up - even with no remainder
IntPtr BitmapBegin = (IntPtr)((Int64)pDest + 8);
byte[] byteArr = new byte[byteSize];
Marshal.Copy(BitmapBegin, byteArr, 0, (Int32)byteSize);
BitArray retVal = new BitArray(byteArr);
retVal.Length = (int)BitmapSize; // truncate to exact cluster count
return retVal;
}
finally
{
CloseHandle(hDevice);
hDevice = IntPtr.Zero;
Marshal.FreeHGlobal(pAlloc);
pAlloc = IntPtr.Zero;
}
}