wfnt.c

vc环境下的pgp源码

/*____________________________________________________________________________
	Copyright (C) 1997 Network Associates Inc. and affiliated companies.
	All rights reserved.

	$Id: WFnt.c,v 1.11 1999/04/01 20:49:59 wjb Exp $
____________________________________________________________________________*/
#include "precomp.h"

//
// Invalid longlong number
//
#define LLINVALID		((ULONGLONG) -1)

//
// Size of the buffer we read file mapping information into.
// The buffer is big enough to hold the 16 bytes that 
// come back at the head of the buffer (the number of entries 
// and the starting virtual cluster), as well as 512 pairs
// of [virtual cluster, logical cluster] pairs.
//
#define	FILEMAPSIZE		(512+2)

//
// Size of the bitmap buffer we pass in. Its large enough to
// hold information for the 16-byte header that's returned
// plus the indicated number of bytes, each of which has 8 bits 
// (imagine that!)
//
#define BITMAPBYTES		4096
#define BITMAPSIZE		(BITMAPBYTES+2*sizeof(ULONGLONG))

//
// Bit shifting array for efficient processing of the bitmap
//
BYTE		BitShift[] = { 1, 2, 4, 8, 16, 32, 64, 128 };

// StatusToError
//
// Takes the status messages and turns them into our
// native wipe free codes.
DWORD StatusToError( NTSTATUS Status )
{
	switch( Status ) 
	{
	case STATUS_SUCCESS:
		return WFE_NOERROR;
	case STATUS_INVALID_PARAMETER:
		return WFE_INVALPARAM; // Must be the metafile
	case STATUS_BUFFER_TOO_SMALL:
		return WFE_OUTOFMEMORY;
	case STATUS_ALREADY_COMMITTED:
		return WFE_ALREADYCOMMIT; // NTFS won't let us. Try anyway
	case STATUS_INVALID_DEVICE_REQUEST:
		return WFE_DRIVENOTSUPPORTED;
	case STATUS_DEVICELOCKED:
		return WFE_COULDNOTLOCK;
	default:
		return WFE_CLUSTERERROR;
	}		  
}

// OpenVolume
//
// Grabs the handle of our logical volume
DWORD OpenVolume( VOLINFO *vi ) 
{
	static char			volumeName[] = "\\\\.\\A:";

	//
	// open the volume
	//
	volumeName[4] = (char)vi->vol0 + 'A'; 
	vi->VolHandle = CreateFile( volumeName, GENERIC_READ, 
					FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 
					0, 0 );
	if( vi->VolHandle == INVALID_HANDLE_VALUE )	{

		return GetLastError();
	}

	return ERROR_SUCCESS;
}

// WipeCluster
//
// WipeCluster uses the patterns stored in filename to 
// eradicate the data in the target cluster of the logical
// drive specified.

DWORD NTWipeCluster( VOLINFO *vi, char *fileName, ULONGLONG Vcn, ULONGLONG target)
{
	DWORD						status;
	IO_STATUS_BLOCK				ioStatus;
	HANDLE						sourceFile;
	LARGE_INTEGER				startVcn, targetLcn;
	DWORD						numClusters;
	MOVEFILE_DESCRIPTOR			moveFile;

	DWORD RetVal;

	RetVal=WFE_NOERROR;

	if(vi->bCountClusters)
	{
		vi->dwClusterCount++;

		if(vi->dwFS==FS_NTFS)
			// NTFS works with 16 cluster segments
			vi->dwClusterCount=vi->dwClusterCount+15; 

		if(UserPressedCancel(vi))
			RetVal=WFE_USERCANCEL;
		return RetVal;
	}

	// 
	// Get numeric parameters
	//
	startVcn.QuadPart=Vcn;
	targetLcn.QuadPart=target;
	numClusters=1;

	if(vi->dwFS==FS_NTFS)
		numClusters=16; // NTFS works with 16 cluster segments
	//
	// Open the file
	//
	sourceFile = CreateFile( fileName, GENERIC_READ, 
					FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 
					FILE_FLAG_NO_BUFFERING, 0 );
	if( sourceFile == INVALID_HANDLE_VALUE ) 
	{
		// Could not open file
		return WFE_COULDNOTREAD ;
	}

	//
	// Setup movefile descriptor and make the call
	//
	memset(&moveFile,0x00,sizeof(MOVEFILE_DESCRIPTOR));
	memset(&ioStatus,0x00,sizeof(IO_STATUS_BLOCK));

	moveFile.FileHandle = sourceFile;
	moveFile.StartVcn = startVcn;
	moveFile.TargetLcn = targetLcn;
	moveFile.NumVcns = numClusters;

	status = NtFsControlFile( vi->VolHandle, NULL, NULL, 0, &ioStatus,
						FSCTL_MOVE_FILE,
						&moveFile, sizeof( moveFile ),
						NULL, 0 );

	RetVal=StatusToError(status);

	// 
	// If the operation is pending, wait for it to finish
	//
	if( status == STATUS_PENDING ) 
	{
		WaitForSingleObject( sourceFile, INFINITE ); 

		RetVal=StatusToError(ioStatus.Status);
	}

	CloseHandle(sourceFile);
	
	// Handle our progress bars and look out for user cancel
	{
		char StrRes[500];
		char statusmsg[500];

		vi->dwClustersWritten=vi->dwClustersWritten+1;
		
		if(vi->dwFS==FS_NTFS)
			// NTFS works with 16 cluster segments
			vi->dwClustersWritten=vi->dwClustersWritten+15; 

		if(vi->dwClustersWritten%10==0)
		{
			float pos;

			LoadString (g_hinst, IDS_PERCENTWRITTEN, StrRes, sizeof(StrRes));

			if(RetVal==WFE_NOERROR)
			{
				sprintf(statusmsg,
					StrRes,
					vi->dwClustersWritten,vi->dwClusterCount);
			}
			else
			{
				sprintf(statusmsg,
					"An error occurred... %d of %d",
					vi->dwClustersWritten,vi->dwClusterCount);
			}

			if(vi->dwFS==FS_NTFS)
			{
				if(RetVal==WFE_INVALPARAM)
				{
					sprintf(statusmsg,
						"Skipping NTFS metadata. %d of %d.",
						vi->dwClustersWritten,vi->dwClusterCount);
				}
				else if(RetVal==WFE_ALREADYCOMMIT)
				{
					sprintf(statusmsg,
						"NTFS won't release cluster. %d of %d.",
						vi->dwClustersWritten,vi->dwClusterCount);
				}
			}

			StatusMessage(statusmsg, FALSE);

			pos = 10 + 
				( (float)vi->dwClustersWritten / 
				  (float)vi->dwClusterCount )
				* 90;

			WipeProgress((int)pos); 
		}
	}

	if(UserPressedCancel(vi))
		RetVal=WFE_USERCANCEL;

	return RetVal;
}

// WipeFreeClusters
//
// Given a logical drive number, routine iterates through free
// clusters and calls WipeCluster to zap the information stored
// there. Note that if changes take place on the drive while
// routine is executes, some clusters may be missed.

DWORD NTWipeFreeClusters( VOLINFO *vi)
{
	DWORD						status,wipestatus;
	PBITMAP_DESCRIPTOR			bitMappings;
	ULONGLONG					startLcn;
	ULONGLONG					nextLcn;
	IO_STATUS_BLOCK				ioStatus;
	ULONGLONG					i;
	BYTE						BitMap[ BITMAPSIZE ];
	char						fileName[MAX_PATH];
	
	//
	// Make the name into a real pathname
	//
	sprintf(fileName, "%C:\\%s", vi->vol0+'A', "PGPwipepattern.tmp" );

	//
	// Start scanning at the cluster offset the user specifies
	//
	bitMappings = (PBITMAP_DESCRIPTOR) BitMap;
	nextLcn = 0;

	while( !(status = NtFsControlFile( vi->VolHandle, NULL, NULL, 0, &ioStatus,
						FSCTL_GET_VOLUME_BITMAP,
						&nextLcn, sizeof( ULONGLONG ),
						bitMappings, BITMAPSIZE )) ||
			 status == STATUS_BUFFER_OVERFLOW ||
			 status == STATUS_PENDING ) 
	{

		// 
		// If the operation is pending, wait for it to finish
		//
		if( status == STATUS_PENDING ) 
		{
			
			WaitForSingleObject( vi->VolHandle, INFINITE );
			
			//
			// Get the status from the status block
			//
			if( ioStatus.Status != STATUS_SUCCESS && 
				ioStatus.Status != STATUS_BUFFER_OVERFLOW ) 
			{
				// Error out
				return StatusToError(ioStatus.Status);
			}
		}

		//
		// Scan through the returned bitmap info, looking for empty clusters
		//
		startLcn = bitMappings->StartLcn;
	
		for( i = 0; i < min( bitMappings->ClustersToEndOfVol, 8*BITMAPBYTES); i++ ) 
		{

			if( !(bitMappings->Map[ i/8 ] & BitShift[ i % 8 ])) 
			{
				wipestatus=NTWipeCluster( vi, fileName, 0, startLcn + i);

				if((wipestatus==WFE_NOERROR)&&(vi->SlackMove))
				{
					// Hey, we were able to do it. Save this cluster for 
					// later slack movement operations since we know its
					// free
					if(vi->PatternBuffer==0)
						vi->PatternBuffer=startLcn+i;
					else if(vi->SlackBufferIndex<SLACKBUFFER)
					{
						vi->SlackBuffer[vi->SlackBufferIndex]=startLcn+i;
						vi->SlackBufferIndex=vi->SlackBufferIndex+1;
					}
				}

				if(((wipestatus==WFE_ALREADYCOMMIT)||(wipestatus==WFE_INVALPARAM))&&(vi->dwFS==FS_NTFS))
				{
					// Couldn't do the move because of MFT, or user is mucking
					// around.... just skip it and we'll get it on the next pass.
					// Only applies to NTFS
					wipestatus=WFE_NOERROR;
				}

				if(wipestatus!=WFE_NOERROR)
				{
					return wipestatus;
				}
			} 

			if(vi->dwFS==FS_NTFS)
				i=i+15; // NTFS works with 16 cluster segments
		}
	
		//
		// End of volume?
		//
		if( status != STATUS_BUFFER_OVERFLOW ) 
		{
		
			return StatusToError(STATUS_SUCCESS);
		}				

		//
		// Move to the next block
		//
		nextLcn = bitMappings->StartLcn + i;
	}

	//
	// We only get here when there's an error
	//

	return StatusToError(status);
}



// GetLastClusterOfFile
//
// Loops through till it finds the last cluster in the chain

DWORD GetLastClusterOfFile(VOLINFO *vi, char *fileName, SLACKMOVE *sm)
{
	DWORD						status;
	int							i;
	HANDLE						sourceFile;
	IO_STATUS_BLOCK				ioStatus;
	ULONGLONG					startVcn;
	PGET_RETRIEVAL_DESCRIPTOR	fileMappings;
	int							lines = 0;
	ULONGLONG					FileMap[ FILEMAPSIZE ];

	// Save name of file for later
	sm->name=fileName;

	//
	// Open the file
	//
	sourceFile = CreateFile( fileName, GENERIC_READ, 
					FILE_SHARE_READ|FILE_SHARE_WRITE, NULL, OPEN_EXISTING, 
					FILE_FLAG_NO_BUFFERING, 0 );

	if( sourceFile == INVALID_HANDLE_VALUE ) 
		return WFE_COULDNOTREAD;

	//
	// Start dumping the mapping information. Go until we hit the end of the
	// file.
	//
	startVcn = 0;
	fileMappings = (PGET_RETRIEVAL_DESCRIPTOR) FileMap;
	while( !(status = NtFsControlFile( sourceFile, NULL, NULL, 0, &ioStatus,
						FSCTL_GET_RETRIEVAL_POINTERS,
						&startVcn, sizeof( startVcn ),
						fileMappings, FILEMAPSIZE * sizeof(LARGE_INTEGER) ) ) ||
			 status == STATUS_BUFFER_OVERFLOW ||
			 status == STATUS_PENDING ) 
	{
		// 
		// If the operation is pending, wait for it to finish
		//
		if( status == STATUS_PENDING ) {
			
			WaitForSingleObject( sourceFile, INFINITE ); 

			//
			// Get the status from the status block
			//
			if( ioStatus.Status != STATUS_SUCCESS && 
				ioStatus.Status != STATUS_BUFFER_OVERFLOW ) 
			{
				// Error out
				return StatusToError(ioStatus.Status);
			}
		}

		//
		// Loop through the buffer of number/cluster pairs, printing them
		// out.
		//
		startVcn = fileMappings->StartVcn;
		for( i = 0; i < (ULONGLONG) fileMappings->NumberOfPairs; i++ ) 
		{
			//
			// On NT 4.0, a compressed virtual run (0-filled) is 
			// identified with a cluster offset of -1
			//
			if( fileMappings->Pair[i].Lcn == LLINVALID ) 
			{
				// Ignore virtual runs since OS is supposed to fill slack
				// with zeros
			} 
			else 
			{
				// This gives us the last cluster Vcn (First+Length-1)
				sm->Vcn=startVcn+(fileMappings->Pair[i].Vcn - startVcn )-1;
		
				if(vi->dwFS==FS_NTFS)
				{
					// We need to 16 cluster align it if NTFS
					sm->Vcn=(sm->Vcn/16)*16;
				}

				// This gives us the last cluster Lcn (Start Location + offset)
				sm->Orig=fileMappings->Pair[i].Lcn+(sm->Vcn-startVcn);
			}
			startVcn = fileMappings->Pair[i].Vcn;
		}

		//
		// If the buffer wasn't overflowed, then we're done
		//
		if( !status ) break;
	}