Memory leak in Windows rawhid sample code

[tni]

The code is from here.

In hid_WINDOWS.c::rawhid_open(), SetupDiGetClassDevs() is used but the returned handle is never released (a call to SetupDiDestroyDeviceInfoList() is required). When frequently calling rawhid_open(), the leak is very substantial.

 

[IBNobody]

Is this the recommended fix? Instead of returning count from inside the for loop, it breaks out instead. SetupDiDestroyDeviceInfoList is called at the end.

//  rawhid_open - open 1 or more devices
//
//    Inputs:
//	max = maximum number of devices to open
//	vid = Vendor ID, or -1 if any
//	pid = Product ID, or -1 if any
//	usage_page = top level usage page, or -1 if any
//	usage = top level usage number, or -1 if any
//    Output:
//	actual number of devices opened
//
__stdcall  int rawhid_open(int max, int vid, int pid, int usage_page, int usage)
{
        GUID guid;
        HDEVINFO info;
        DWORD index=0, reqd_size;
        SP_DEVICE_INTERFACE_DATA iface;
        SP_DEVICE_INTERFACE_DETAIL_DATA *details;
        HIDD_ATTRIBUTES attrib;
        PHIDP_PREPARSED_DATA hid_data;
        HIDP_CAPS capabilities;
        HANDLE h;
        BOOL ret;
	hid_t *hid;
	int count=0;

	if (first_hid) free_all_hid();
	if (max < 1) return 0;
	if (!rx_event) {
		rx_event = CreateEvent(NULL, TRUE, TRUE, NULL);
		tx_event = CreateEvent(NULL, TRUE, TRUE, NULL);
		InitializeCriticalSection(&rx_mutex);
		InitializeCriticalSection(&tx_mutex);
	}
	HidD_GetHidGuid(&guid);
	info = SetupDiGetClassDevs(&guid, NULL, NULL, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
	if (info == INVALID_HANDLE_VALUE) return 0;
	for (index=0; 1 ;index++) {
		iface.cbSize = sizeof(SP_DEVICE_INTERFACE_DATA);
		ret = SetupDiEnumDeviceInterfaces(info, NULL, &guid, index, &iface);
		if (!ret) break;
		SetupDiGetInterfaceDeviceDetail(info, &iface, NULL, 0, &reqd_size, NULL);
		details = (SP_DEVICE_INTERFACE_DETAIL_DATA *)malloc(reqd_size);
		if (details == NULL) continue;

		memset(details, 0, reqd_size);
		details->cbSize = sizeof(SP_DEVICE_INTERFACE_DETAIL_DATA);
		ret = SetupDiGetDeviceInterfaceDetail(info, &iface, details, reqd_size, NULL, NULL);
		if (!ret) {
			free(details);
			continue;
		}
		h = CreateFile(details->DevicePath, GENERIC_READ|GENERIC_WRITE,
			FILE_SHARE_READ|FILE_SHARE_WRITE, NULL,
			OPEN_EXISTING, FILE_FLAG_OVERLAPPED, NULL);
		free(details);
		if (h == INVALID_HANDLE_VALUE) continue;
		attrib.Size = sizeof(HIDD_ATTRIBUTES);
		ret = HidD_GetAttributes(h, &attrib);
		//printf("vid: %4x\n", attrib.VendorID);
		if (!ret || (vid > 0 && attrib.VendorID != vid) ||
		  (pid > 0 && attrib.ProductID != pid) ||
		  !HidD_GetPreparsedData(h, &hid_data)) {
			CloseHandle(h);
			continue;
		}
		if (!HidP_GetCaps(hid_data, &capabilities) ||
		  (usage_page > 0 && capabilities.UsagePage != usage_page) ||
		  (usage > 0 && capabilities.Usage != usage)) {
			HidD_FreePreparsedData(hid_data);
			CloseHandle(h);
			continue;
		}
		HidD_FreePreparsedData(hid_data);
		hid = (struct hid_struct *)malloc(sizeof(struct hid_struct));
		if (!hid) {
			CloseHandle(h);
			continue;
		}
		hid->handle = h;
		hid->pid = attrib.ProductID;
		hid->vid = attrib.VendorID;
		hid->usage_page = capabilities.UsagePage;
		hid->usage = capabilities.Usage;
		hid->open = 1;
		add_hid(hid);
		count++;
		if (count >= max) break;
	}
	SetupDiDestroyDeviceInfoList(info);
	return count;
}