1 /* FreezeDLLMain.cpp

     2 

     3 This is a DLLMain suitable for frozen applications/DLLs on

     4 a Windows platform.

     5 

     6 The general problem is that many Python extension modules may define

     7 DLL main functions, but when statically linked together to form

     8 a frozen application, this DLLMain symbol exists multiple times.

     9 

    10 The solution is:

    11 * Each module checks for a frozen build, and if so, defines its DLLMain

    12   function as "__declspec(dllexport) DllMain%module%" 

    13   (eg, DllMainpythoncom, or DllMainpywintypes)

    14 

    15 * The frozen .EXE/.DLL links against this module, which provides

    16   the single DllMain.

    17 

    18 * This DllMain attempts to locate and call the DllMain for each

    19   of the extension modules.

    20 

    21 * This code also has hooks to "simulate" DllMain when used from

    22   a frozen .EXE.

    23 

    24 At this stage, there is a static table of "possibly embedded modules".

    25 This should change to something better, but it will work OK for now.

    26 

    27 Note that this scheme does not handle dependencies in the order

    28 of DllMain calls - except it does call pywintypes first :-)

    29 

    30 As an example of how an extension module with a DllMain should be

    31 changed, here is a snippet from the pythoncom extension module.

    32 

    33   // end of example code from pythoncom's DllMain.cpp

    34   #ifndef BUILD_FREEZE

    35   #define DLLMAIN DllMain

    36   #define DLLMAIN_DECL

    37   #else

    38   #define DLLMAIN DllMainpythoncom

    39   #define DLLMAIN_DECL __declspec(dllexport)

    40   #endif

    41 

    42   extern "C" DLLMAIN_DECL

    43   BOOL WINAPI DLLMAIN(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)

    44   // end of example code from pythoncom's DllMain.cpp

    45 

    46 ***************************************************************************/

    47 #include "windows.h"

    48 

    49 static char *possibleModules[] = {

    50 	"pywintypes",

    51 	"pythoncom",

    52 	"win32ui",

    53 	NULL,

    54 };

    55 

    56 BOOL CallModuleDllMain(char *modName, DWORD dwReason);

    57 

    58 

    59 /*

    60   Called by a frozen .EXE only, so that built-in extension

    61   modules are initialized correctly

    62 */

    63 void PyWinFreeze_ExeInit(void)

    64 {

    65 	char **modName;

    66 	for (modName = possibleModules;*modName;*modName++) {

    67 /*		printf("Initialising '%s'\n", *modName); */

    68 		CallModuleDllMain(*modName, DLL_PROCESS_ATTACH);

    69 	}

    70 }

    71 

    72 /*

    73   Called by a frozen .EXE only, so that built-in extension

    74   modules are cleaned up 

    75 */

    76 void PyWinFreeze_ExeTerm(void)

    77 {

    78 	// Must go backwards

    79 	char **modName;

    80 	for (modName = possibleModules+(sizeof(possibleModules) / sizeof(char *))-2;

    81 	     modName >= possibleModules;

    82 	     *modName--) {

    83 /*		printf("Terminating '%s'\n", *modName);*/

    84 		CallModuleDllMain(*modName, DLL_PROCESS_DETACH);

    85 	}

    86 }

    87 

    88 BOOL WINAPI DllMain(HINSTANCE hInstance, DWORD dwReason, LPVOID lpReserved)

    89 {

    90 	BOOL ret = TRUE;

    91 	switch (dwReason) {

    92 		case DLL_PROCESS_ATTACH: 

    93 		{

    94 			char **modName;

    95 			for (modName = possibleModules;*modName;*modName++) {

    96 				BOOL ok = CallModuleDllMain(*modName, dwReason);

    97 				if (!ok)

    98 					ret = FALSE;

    99 			}

   100 			break;

   101 		}

   102 		case DLL_PROCESS_DETACH: 

   103 		{

   104 			// Must go backwards

   105 			char **modName;

   106 			for (modName = possibleModules+(sizeof(possibleModules) / sizeof(char *))-2;

   107 			     modName >= possibleModules;

   108 			     *modName--)

   109 				CallModuleDllMain(*modName, DLL_PROCESS_DETACH);

   110 			break;

   111 		}

   112 	}

   113 	return ret;

   114 }

   115 

   116 BOOL CallModuleDllMain(char *modName, DWORD dwReason)

   117 {

   118 	BOOL (WINAPI * pfndllmain)(HINSTANCE, DWORD, LPVOID);

   119 

   120 	char funcName[255];

   121 	HMODULE hmod = GetModuleHandle(NULL);

   122 	strcpy(funcName, "_DllMain");

   123 	strcat(funcName, modName);

   124 	strcat(funcName, "@12"); // stdcall convention.

   125 	pfndllmain = (BOOL (WINAPI *)(HINSTANCE, DWORD, LPVOID))GetProcAddress(hmod, funcName);

   126 	if (pfndllmain==NULL) {

   127 		/* No function by that name exported - then that module does

   128  		   not appear in our frozen program - return OK

   129                 */

   130 		return TRUE;

   131 	}

   132 	return (*pfndllmain)(hmod, dwReason, NULL);

   133 }

   134