Creating reparse point

reparse.cpp

// -----------------------------------------------------------------------
//   Includes
// -----------------------------------------------------------------------

#include <Windows.h>
#include <tchar.h>
#include <stdio.h>

// -----------------------------------------------------------------------
//   Functions
// -----------------------------------------------------------------------

/*++
*		Setting required privileges
*		@param priv privilege
--*/
void GetPrivilege(LPCTSTR priv)
{
	HANDLE hToken;
	TOKEN_PRIVILEGES tp;
	OpenProcessToken(GetCurrentProcess(),
		TOKEN_ADJUST_PRIVILEGES, &hToken);
	LookupPrivilegeValue(NULL, priv, &tp.Privileges[0].Luid);
	tp.PrivilegeCount = 1;
	tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
	AdjustTokenPrivileges(hToken, FALSE, &tp,
		sizeof(TOKEN_PRIVILEGES), NULL, NULL);
	CloseHandle(hToken);
}

int _tmain(int argc, TCHAR** argv)
{
	// 1. required privileges
	GetPrivilege(SE_BACKUP_NAME);
	GetPrivilege(SE_RESTORE_NAME);
	GetPrivilege(SE_CREATE_SYMBOLIC_LINK_NAME);

	// 2. prepare reparse structure
	TCHAR data[] = _T("My reparse data");
	BYTE reparseBuffer[sizeof(REPARSE_GUID_DATA_BUFFER) + sizeof(data)];
	PREPARSE_GUID_DATA_BUFFER rd = (PREPARSE_GUID_DATA_BUFFER) reparseBuffer;

	ZeroMemory(reparseBuffer, sizeof(REPARSE_GUID_DATA_BUFFER) + sizeof(data));

	// {07A869CB-F647-451F-840D-964A3AF8C0B6}
	static const GUID my_guid =
	{
		0x7a869cb, 0xf647, 0x451f,
		{ 0x84, 0xd, 0x96, 0x4a, 0x3a, 0xf8, 0xc0, 0xb6 }
	};

	rd->ReparseTag = 0xFF00;
	rd->ReparseDataLength = sizeof(data);
	rd->Reserved = 0;
	rd->ReparseGuid = my_guid;
	memcpy(rd->GenericReparseBuffer.DataBuffer, &data, sizeof(data));

	DWORD dwLen = 0;
	LPCTSTR name = _T("TestReparseFile");

	// 3. create empty file
	_tprintf(_T("Creating empty file\n"));
	HANDLE hFile = CreateFile(name,
		GENERIC_READ | GENERIC_WRITE, 
		0, NULL,
		CREATE_NEW, 
		FILE_FLAG_OPEN_REPARSE_POINT | FILE_FLAG_BACKUP_SEMANTICS,
		NULL);
	if (INVALID_HANDLE_VALUE == hFile)
	{
		_tprintf(_T("Failed to create file\n"));
		return -1;
	}

	// 4. Fill file with reparse
	_tprintf(_T("Creating reparse\n"));
	if (!DeviceIoControl(hFile, FSCTL_SET_REPARSE_POINT,
		rd, rd->ReparseDataLength + REPARSE_GUID_DATA_BUFFER_HEADER_SIZE,
		NULL, 0, &dwLen, NULL))
	{
		CloseHandle(hFile);
		DeleteFile(name);

		_tprintf(_T("Failed to create reparse\n"));
		return -1;
	}

	CloseHandle(hFile);

	_tprintf(_T("SUCCESS\n"));
	return 0;
}