Thread: Memory Leak Help

Hi,

Im having some problems with a memory leak in some of my code, to be honest i have never really covered much 'memory managment' in the past and i have been away from programming for a few years, In the code below, the top function is called every so often, and upps the programs memory quite significantly over the course of a few minutes/several calls.

I allocated the main buffer memory with GlobalAlloc and free it later on with GlobalFree(). I cant think whats causing the leak? In the second function i assume strstr allocates memory itself?

Any ideas?

Code:

bool CheckData(HWND hWnd, wchar_t szUserName[128], wchar_t szPasswd[128], wchar_t szTmpPath[], data *md)
{
		HINTERNET hInternet;
		HINTERNET hConnect;
		LPCTSTR szServer;
		LPCWSTR szRSSLocation;
		HINTERNET hRequest;
		BOOL bResult;
		HANDLE hFile;
		DWORD dwBytesAvailable;

		md->error = 0;		// No Errors Yet!
		
		wchar_t file_path[max_path];
		wchar_t szDataFile[9] = _T("rss.xml");
		szServer = _T("");
		szRSSLocation = _T("");
		
		wcscpy_s(file_path, lengthof(file_path), szTmpPath);
		wcscat_s(file_path, lengthof(file_path), szDataFile);
		

		hInternet = InternetOpen(_T("WinInetGet/0.1"), INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
		if(hInternet == NULL) 
		{
			md->error = INTERNET_HAN; 
			return false;
		}

		hConnect = InternetConnect(hInternet, szServer, INTERNET_DEFAULT_HTTPS_PORT, szUserName, 
		szPasswd, INTERNET_SERVICE_HTTP, 0, 0);
		if(hConnect == NULL) 
		{
			md->error = INTERNET_HAN; 
			return false;
		}

		hRequest = HttpOpenRequest(hConnect, _T("GET"), szRSSLocation, NULL,
		NULL, NULL,
		INTERNET_FLAG_SECURE, 0);
		if(hRequest == NULL) 
		{
			md->error = INTERNET_HAN; 
			return false;
		}

		bResult = HttpSendRequest(hRequest, NULL, 0, NULL, 0);
		if(bResult == FALSE)
		{
			md->error = ERR_HTTP_REQ;
			return false;
		}
		
		

		hFile = CreateFile(file_path, GENERIC_WRITE, 0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
		if(hFile == INVALID_HANDLE_VALUE)
		{
			md->error = ERR_FILE_HANDLE;
			return false;
		}

		while (InternetQueryDataAvailable(hRequest, &dwBytesAvailable, 0, 0))
		{
			BYTE *pMessageBody = (BYTE *) GlobalAlloc(GMEM_FIXED, dwBytesAvailable+1);
			DWORD dwBytesRead;
			DWORD dwWritten;

			BOOL bResult = InternetReadFile(hRequest, pMessageBody,
						dwBytesAvailable, &dwBytesRead);

			
			if (!bResult)
			{
				md->error = ERR_HTTPS_FAIL;
				GlobalFree(pMessageBody);
				return false;
				break;
			}

			if (dwBytesRead == 0)
				break;	// EOF

			pMessageBody[dwBytesRead] = '\0';
			
			
			if(hFile != INVALID_HANDLE_VALUE)
			{
				WriteFile(hFile, pMessageBody, dwBytesRead, &dwWritten, NULL);
			}
			else
			{
				md->error = ERR_FILE_HANDLE;
				GlobalFree(pMessageBody);
				break;
			}
			
			// Free Memory
			GlobalFree(pMessageBody);
		}
	
		
		// Close connections
		CloseHandle(hFile);
		InternetCloseHandle(hInternet);
		InternetCloseHandle(hConnect);
		InternetCloseHandle(hRequest);
		
		// Begin XML Parsing
		bResult = ParseXML(file_path, md);
		if(bResult == FALSE)
		{
			md->error = ERR_PARSE;
		}

		// Delete temp XML file
		DeleteFile(file_path);


	if(md->error == 0)
		return true;
	else
		return false;
}


bool ParseXML(LPCWSTR XMLFile, data *md)
{
	HANDLE hFile;
	DWORD dwActBytes;
	DWORD filesize;
	char *szXML;
	char *nodea;
	char nodeb[13];
	

	hFile = CreateFile(XMLFile, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
	
	if(hFile != INVALID_HANDLE_VALUE)
	{
		// Get file size and allocate buffer memory
		filesize = GetFileSize(hFile, NULL);
		szXML = (char *) GlobalAlloc(GMEM_FIXED, filesize+1);

		SetFilePointer(hFile, 0, NULL, FILE_BEGIN);

		// read in entire xml file into the XML buffer
		ReadFile(hFile, szXML, filesize, &dwActBytes, NULL);

		szXML[dwActBytes] = 0;

		CloseHandle(hFile);

		MessageBoxA(NULL, szXML, "XML Data", NULL);
	}

	else
	{
		return false;
	}
	

	// Get the <data> node
	nodea = strstr(szXML, "<data>");
	
	if(nodea != NULL)
	{
	nodeb[0] = nodea[11];
	
	int pos = 0;
	int a = 11;

	do
	{
		nodeb[pos] = nodea[a];
		pos++;
		a++;

	} while(nodea[a] != '<');

	nodeb[pos] = 0;

	// Fill in the data structure
	md->new_messages = atoi(nodeb);
	}

	else
	{
		md->error = ERR_UNAUTH;
	}

	// Free Memory
	GlobalFree(szXML);
	
	return true;
}

Thanks very much for any help/advice on correct memory allocation