cfilesystemwatcher.cpp

来自「PGP8.0源码 请认真阅读您的文件包然后写出其具体功能」· C++ 代码 · 共 191 行

/*____________________________________________________________________________
		Copyright (C) 2002 PGP Corporation
        All rights reserved.

        $Id: CFilesystemWatcher.cpp,v 1.6 2002/08/06 20:09:30 dallen Exp $
____________________________________________________________________________*/

#include "pgpClassesConfig.h"
#include "CFilesystemWatcher.h"

_USING_PGP

// Types

struct CFilesystemWatcher::WatchedBufInfo : 
	public CListableObject<CFilesystemWatcher::WatchedBufInfo>
{
	void	*buf;
};


// Class CFilesystemWatcher static variables

CFilesystemWatcher	*CFilesystemWatcher::mHookInstance;


// Class CFilesystemWatcher member functions

CFilesystemWatcher::CFilesystemWatcher()
{
	mHookInstance = this;
	Status() = mWBIAllocator.Status();
}

CComboError 
CFilesystemWatcher::WatchForBuffer(void *buf)
{
	CComboError	error;

	WatchedBufInfo	*pWBI;
	error = mWBIAllocator.Allocate(pWBI);

	if (error.IsntError())
	{
		pWBI->buf = buf;
		mWBIList.AddHead(pWBI);
	}

	return error;
}

CComboError 
CFilesystemWatcher::StopWatchingForBuffer(void *buf)
{
	CComboError	error;

	PGPBoolean		foundBufInfo	= FALSE;
	WatchedBufInfo	*pWBI			= mWBIList.Head();

	// Find the info structure for this buffer.
	while (IsntNull(pWBI))
	{
		if (pWBI->buf == buf)
		{
			foundBufInfo = TRUE;
			break;
		}
		else
		{
			pWBI = mWBIList.Next(pWBI);
		}
	}

	if (!foundBufInfo)
		error.pgpErr = kPGPError_BadParams;

	// Free the list entry.
	mWBIList.Remove(pWBI);
	mWBIAllocator.Free(pWBI);

	return error;
}

CComboError 
CFilesystemWatcher::Startup()
{
	CComboError	error;

	mPreviousHook = IFSMgr_InstallFileSystemApiHook(FilesystemHook);

	if (IsNull(mPreviousHook))
		error.pgpErr = kPGPError_VolumeOpFailed;

	return error;
}

void 
CFilesystemWatcher::Shutdown()
{
	if (IsntNull(mPreviousHook))
	{
		IFSMgr_RemoveFileSystemApiHook(FilesystemHook);
		mPreviousHook = NULL;
	}
}

int 
CFilesystemWatcher::FilesystemHookAux(
	pIFSFunc	pfn, 
	int			func, 
	int			drive, 
	int			resType, 
	int			codePage, 
	pioreq		pir)
{
	// fix not being able to open > 2GB files
	switch (func)
	{
	case IFSFN_OPEN:
		if (pir->ir_options & R0_NO_CACHE)
			pir->ir_attr |= OPEN_FLAGS_EXTENDED_SIZE;

		// fix for bug in ID: Q183173
		if ((pir->ir_options & OPEN_FLAGS_REOPEN) && 
			(pir->ir_pid == -1))
		{
			switch (pir->ir_flags)
			{
			case ACCESS_WRITEONLY:
				pir->ir_flags = ACCESS_READWRITE;
				break;
			}
		}
		break;

	// fix access flags on our read/write requests
	case IFSFN_READ:
	case IFSFN_WRITE:
	{
		PGPBoolean		foundBuffer	= FALSE;
		void			*buf		= static_cast<void *>(pir->ir_data);
		WatchedBufInfo	*pWBI		= mWBIList.Head();

		while (IsntNull(pWBI))
		{
			if (pWBI->buf == buf)
			{
				foundBuffer = TRUE;
				break;
			}
			else
			{
				pWBI = mWBIList.Next(pWBI);
			}
		}

		if (foundBuffer)
		{
			// OK, this is one of our virtual volume requests. Restore the
			// memory-mapped flag.

			PGPUInt32	oldOptions	= pir->ir_options;
			pir->ir_options |= R0_MM_READ_WRITE;

			int	ret	= (*mPreviousHook)(pfn, func, drive, resType, codePage, 
				pir);

			pir->ir_options = oldOptions;
			return ret;
		}
		break;
	}
	}

	return (*mPreviousHook)(pfn, func, drive, resType, codePage, pir);
}

int 
_cdecl 
CFilesystemWatcher::FilesystemHook(
	pIFSFunc	pfn, 
	int			func, 
	int			drive, 
	int			resType, 
	int			codePage, 
	pioreq		pir)
{
	return mHookInstance->FilesystemHookAux(pfn, func, drive, resType, 
		codePage, pir);
}