Windows/WinCE: Improve the run-time dynamic linking scheme

Prior to this commit, the Windows and WinCE backends had a specific
shortcoming when loading DLLs, that being that once loaded they were
never unloaded. This commit improves this by providing a means to
unload the DLLs during cleanup.

Note that the use of GetModuleHandle() has been removed in favor of
the exclusive use of LoadLibrary(). This was done to ensure that a
reference count is taken against the loaded DLL, which guards against
some other part of the application unloading the DLL that libusb
is currently using.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>

1 files changed, 41 insertions, 32 deletions

diff --git a/libusb/os/windows_winusb.h b/libusb/os/windows_winusb.h
index 8f53c4a..047f2e2 100644
--- a/libusb/os/windows_winusb.h
+++ b/libusb/os/windows_winusb.h
@@ -314,25 +314,32 @@ struct driver_lookup {
 };
 
 /* OLE32 dependency */
-DLL_DECLARE_PREFIXED(WINAPI, HRESULT, p, CLSIDFromString, (LPCOLESTR, LPCLSID));
+DLL_DECLARE_HANDLE(OLE32);
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, HRESULT, p, CLSIDFromString, (LPCOLESTR, LPCLSID));
 
+/* Kernel32 dependencies */
+DLL_DECLARE_HANDLE(Kernel32);
 /* This call is only available from XP SP2 */
-DLL_DECLARE_PREFIXED(WINAPI, BOOL, p, IsWow64Process, (HANDLE, PBOOL));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, BOOL, p, IsWow64Process, (HANDLE, PBOOL));
 
 /* SetupAPI dependencies */
-DLL_DECLARE_PREFIXED(WINAPI, HDEVINFO, p, SetupDiGetClassDevsA, (const GUID*, PCSTR, HWND, DWORD));
-DLL_DECLARE_PREFIXED(WINAPI, BOOL, p, SetupDiEnumDeviceInfo, (HDEVINFO, DWORD, PSP_DEVINFO_DATA));
-DLL_DECLARE_PREFIXED(WINAPI, BOOL, p, SetupDiEnumDeviceInterfaces, (HDEVINFO, PSP_DEVINFO_DATA,
+DLL_DECLARE_HANDLE(SetupAPI);
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, HDEVINFO, p, SetupDiGetClassDevsA, (const GUID*, PCSTR, HWND, DWORD));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, BOOL, p, SetupDiEnumDeviceInfo, (HDEVINFO, DWORD, PSP_DEVINFO_DATA));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, BOOL, p, SetupDiEnumDeviceInterfaces, (HDEVINFO, PSP_DEVINFO_DATA,
 			const GUID*, DWORD, PSP_DEVICE_INTERFACE_DATA));
-DLL_DECLARE_PREFIXED(WINAPI, BOOL, p, SetupDiGetDeviceInterfaceDetailA, (HDEVINFO, PSP_DEVICE_INTERFACE_DATA,
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, BOOL, p, SetupDiGetDeviceInterfaceDetailA, (HDEVINFO, PSP_DEVICE_INTERFACE_DATA,
 			PSP_DEVICE_INTERFACE_DETAIL_DATA_A, DWORD, PDWORD, PSP_DEVINFO_DATA));
-DLL_DECLARE_PREFIXED(WINAPI, BOOL, p, SetupDiDestroyDeviceInfoList, (HDEVINFO));
-DLL_DECLARE_PREFIXED(WINAPI, HKEY, p, SetupDiOpenDevRegKey, (HDEVINFO, PSP_DEVINFO_DATA, DWORD, DWORD, DWORD, REGSAM));
-DLL_DECLARE_PREFIXED(WINAPI, BOOL, p, SetupDiGetDeviceRegistryPropertyA, (HDEVINFO,
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, BOOL, p, SetupDiDestroyDeviceInfoList, (HDEVINFO));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, HKEY, p, SetupDiOpenDevRegKey, (HDEVINFO, PSP_DEVINFO_DATA, DWORD, DWORD, DWORD, REGSAM));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, BOOL, p, SetupDiGetDeviceRegistryPropertyA, (HDEVINFO,
 			PSP_DEVINFO_DATA, DWORD, PDWORD, PBYTE, DWORD, PDWORD));
-DLL_DECLARE_PREFIXED(WINAPI, HKEY, p, SetupDiOpenDeviceInterfaceRegKey, (HDEVINFO, PSP_DEVICE_INTERFACE_DATA, DWORD, DWORD));
-DLL_DECLARE_PREFIXED(WINAPI, LONG, p, RegQueryValueExW, (HKEY, LPCWSTR, LPDWORD, LPDWORD, LPBYTE, LPDWORD));
-DLL_DECLARE_PREFIXED(WINAPI, LONG, p, RegCloseKey, (HKEY));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, HKEY, p, SetupDiOpenDeviceInterfaceRegKey, (HDEVINFO, PSP_DEVICE_INTERFACE_DATA, DWORD, DWORD));
+
+/* AdvAPI32 dependencies */
+DLL_DECLARE_HANDLE(AdvAPI32);
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, LONG, p, RegQueryValueExW, (HKEY, LPCWSTR, LPDWORD, LPDWORD, LPBYTE, LPDWORD));
+DLL_DECLARE_FUNC_PREFIXED(WINAPI, LONG, p, RegCloseKey, (HKEY));
 
 /*
  * Windows DDK API definitions. Most of it copied from MinGW's includes
@@ -413,10 +420,11 @@ typedef enum USB_HUB_NODE {
 } USB_HUB_NODE;
 
 /* Cfgmgr32.dll interface */
-DLL_DECLARE(WINAPI, CONFIGRET, CM_Get_Parent, (PDEVINST, DEVINST, ULONG));
-DLL_DECLARE(WINAPI, CONFIGRET, CM_Get_Child, (PDEVINST, DEVINST, ULONG));
-DLL_DECLARE(WINAPI, CONFIGRET, CM_Get_Sibling, (PDEVINST, DEVINST, ULONG));
-DLL_DECLARE(WINAPI, CONFIGRET, CM_Get_Device_IDA, (DEVINST, PCHAR, ULONG, ULONG));
+DLL_DECLARE_HANDLE(Cfgmgr32);
+DLL_DECLARE_FUNC(WINAPI, CONFIGRET, CM_Get_Parent, (PDEVINST, DEVINST, ULONG));
+DLL_DECLARE_FUNC(WINAPI, CONFIGRET, CM_Get_Child, (PDEVINST, DEVINST, ULONG));
+DLL_DECLARE_FUNC(WINAPI, CONFIGRET, CM_Get_Sibling, (PDEVINST, DEVINST, ULONG));
+DLL_DECLARE_FUNC(WINAPI, CONFIGRET, CM_Get_Device_IDA, (DEVINST, PCHAR, ULONG, ULONG));
 
 #define IOCTL_USB_GET_HUB_CAPABILITIES_EX \
 	CTL_CODE( FILE_DEVICE_USB, USB_GET_HUB_CAPABILITIES_EX, METHOD_BUFFERED, FILE_ANY_ACCESS)
@@ -934,19 +942,20 @@ typedef struct _HIDP_VALUE_CAPS {
 	} u;
 } HIDP_VALUE_CAPS, *PHIDP_VALUE_CAPS;
 
-DLL_DECLARE(WINAPI, BOOL, HidD_GetAttributes, (HANDLE, PHIDD_ATTRIBUTES));
-DLL_DECLARE(WINAPI, VOID, HidD_GetHidGuid, (LPGUID));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetPreparsedData, (HANDLE, PHIDP_PREPARSED_DATA *));
-DLL_DECLARE(WINAPI, BOOL, HidD_FreePreparsedData, (PHIDP_PREPARSED_DATA));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetManufacturerString, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetProductString, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetSerialNumberString, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, LONG, HidP_GetCaps, (PHIDP_PREPARSED_DATA, PHIDP_CAPS));
-DLL_DECLARE(WINAPI, BOOL, HidD_SetNumInputBuffers, (HANDLE, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_SetFeature, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetFeature, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetPhysicalDescriptor, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_GetInputReport, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_SetOutputReport, (HANDLE, PVOID, ULONG));
-DLL_DECLARE(WINAPI, BOOL, HidD_FlushQueue, (HANDLE));
-DLL_DECLARE(WINAPI, BOOL, HidP_GetValueCaps, (HIDP_REPORT_TYPE, PHIDP_VALUE_CAPS, PULONG, PHIDP_PREPARSED_DATA));
+DLL_DECLARE_HANDLE(hid);
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetAttributes, (HANDLE, PHIDD_ATTRIBUTES));
+DLL_DECLARE_FUNC(WINAPI, VOID, HidD_GetHidGuid, (LPGUID));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetPreparsedData, (HANDLE, PHIDP_PREPARSED_DATA *));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_FreePreparsedData, (PHIDP_PREPARSED_DATA));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetManufacturerString, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetProductString, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetSerialNumberString, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, LONG, HidP_GetCaps, (PHIDP_PREPARSED_DATA, PHIDP_CAPS));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_SetNumInputBuffers, (HANDLE, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_SetFeature, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetFeature, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetPhysicalDescriptor, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_GetInputReport, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_SetOutputReport, (HANDLE, PVOID, ULONG));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidD_FlushQueue, (HANDLE));
+DLL_DECLARE_FUNC(WINAPI, BOOL, HidP_GetValueCaps, (HIDP_REPORT_TYPE, PHIDP_VALUE_CAPS, PULONG, PHIDP_PREPARSED_DATA));
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