| 1 | /*
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| 2 |
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| 3 | Entry point for the Windows NT DLL.
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| 4 |
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| 5 | About the only reason for having this, is so initall() can automatically
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| 6 | be called, removing that burden (and possible source of frustration if
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| 7 | forgotten) from the programmer.
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| 8 |
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| 9 | */
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| 10 |
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| 11 | #include "Python.h"
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| 12 | #include "windows.h"
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| 13 |
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| 14 | #ifdef Py_ENABLE_SHARED
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| 15 | char dllVersionBuffer[16] = ""; // a private buffer
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| 16 |
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| 17 | // Python Globals
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| 18 | HMODULE PyWin_DLLhModule = NULL;
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| 19 | const char *PyWin_DLLVersionString = dllVersionBuffer;
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| 20 |
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| 21 | // Windows "Activation Context" work:
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| 22 | // Our .pyd extension modules are generally built without a manifest (ie,
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| 23 | // those included with Python and those built with a default distutils.
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| 24 | // This requires we perform some "activation context" magic when loading our
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| 25 | // extensions. In summary:
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| 26 | // * As our DLL loads we save the context being used.
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| 27 | // * Before loading our extensions we re-activate our saved context.
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| 28 | // * After extension load is complete we restore the old context.
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| 29 | // As an added complication, this magic only works on XP or later - we simply
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| 30 | // use the existence (or not) of the relevant function pointers from kernel32.
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| 31 | // See bug 4566 (http://python.org/sf/4566) for more details.
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| 32 |
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| 33 | typedef BOOL (WINAPI * PFN_GETCURRENTACTCTX)(HANDLE *);
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| 34 | typedef BOOL (WINAPI * PFN_ACTIVATEACTCTX)(HANDLE, ULONG_PTR *);
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| 35 | typedef BOOL (WINAPI * PFN_DEACTIVATEACTCTX)(DWORD, ULONG_PTR);
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| 36 | typedef BOOL (WINAPI * PFN_ADDREFACTCTX)(HANDLE);
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| 37 | typedef BOOL (WINAPI * PFN_RELEASEACTCTX)(HANDLE);
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| 38 |
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| 39 | // locals and function pointers for this activation context magic.
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| 40 | static HANDLE PyWin_DLLhActivationContext = NULL; // one day it might be public
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| 41 | static PFN_GETCURRENTACTCTX pfnGetCurrentActCtx = NULL;
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| 42 | static PFN_ACTIVATEACTCTX pfnActivateActCtx = NULL;
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| 43 | static PFN_DEACTIVATEACTCTX pfnDeactivateActCtx = NULL;
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| 44 | static PFN_ADDREFACTCTX pfnAddRefActCtx = NULL;
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| 45 | static PFN_RELEASEACTCTX pfnReleaseActCtx = NULL;
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| 46 |
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| 47 | void _LoadActCtxPointers()
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| 48 | {
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| 49 | HINSTANCE hKernel32 = GetModuleHandleW(L"kernel32.dll");
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| 50 | if (hKernel32)
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| 51 | pfnGetCurrentActCtx = (PFN_GETCURRENTACTCTX) GetProcAddress(hKernel32, "GetCurrentActCtx");
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| 52 | // If we can't load GetCurrentActCtx (ie, pre XP) , don't bother with the rest.
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| 53 | if (pfnGetCurrentActCtx) {
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| 54 | pfnActivateActCtx = (PFN_ACTIVATEACTCTX) GetProcAddress(hKernel32, "ActivateActCtx");
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| 55 | pfnDeactivateActCtx = (PFN_DEACTIVATEACTCTX) GetProcAddress(hKernel32, "DeactivateActCtx");
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| 56 | pfnAddRefActCtx = (PFN_ADDREFACTCTX) GetProcAddress(hKernel32, "AddRefActCtx");
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| 57 | pfnReleaseActCtx = (PFN_RELEASEACTCTX) GetProcAddress(hKernel32, "ReleaseActCtx");
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| 58 | }
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| 59 | }
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| 60 |
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| 61 | ULONG_PTR _Py_ActivateActCtx()
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| 62 | {
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| 63 | ULONG_PTR ret = 0;
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| 64 | if (PyWin_DLLhActivationContext && pfnActivateActCtx)
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| 65 | if (!(*pfnActivateActCtx)(PyWin_DLLhActivationContext, &ret)) {
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| 66 | OutputDebugString("Python failed to activate the activation context before loading a DLL\n");
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| 67 | ret = 0; // no promise the failing function didn't change it!
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| 68 | }
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| 69 | return ret;
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| 70 | }
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| 71 |
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| 72 | void _Py_DeactivateActCtx(ULONG_PTR cookie)
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| 73 | {
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| 74 | if (cookie && pfnDeactivateActCtx)
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| 75 | if (!(*pfnDeactivateActCtx)(0, cookie))
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| 76 | OutputDebugString("Python failed to de-activate the activation context\n");
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| 77 | }
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| 78 |
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| 79 | BOOL WINAPI DllMain (HANDLE hInst,
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| 80 | ULONG ul_reason_for_call,
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| 81 | LPVOID lpReserved)
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| 82 | {
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| 83 | switch (ul_reason_for_call)
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| 84 | {
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| 85 | case DLL_PROCESS_ATTACH:
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| 86 | PyWin_DLLhModule = hInst;
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| 87 | // 1000 is a magic number I picked out of the air. Could do with a #define, I spose...
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| 88 | LoadString(hInst, 1000, dllVersionBuffer, sizeof(dllVersionBuffer));
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| 89 |
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| 90 | // and capture our activation context for use when loading extensions.
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| 91 | _LoadActCtxPointers();
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| 92 | if (pfnGetCurrentActCtx && pfnAddRefActCtx)
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| 93 | if ((*pfnGetCurrentActCtx)(&PyWin_DLLhActivationContext))
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| 94 | if (!(*pfnAddRefActCtx)(PyWin_DLLhActivationContext))
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| 95 | OutputDebugString("Python failed to load the default activation context\n");
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| 96 | break;
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| 97 |
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| 98 | case DLL_PROCESS_DETACH:
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| 99 | if (pfnReleaseActCtx)
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| 100 | (*pfnReleaseActCtx)(PyWin_DLLhActivationContext);
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| 101 | break;
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| 102 | }
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| 103 | return TRUE;
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| 104 | }
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| 105 |
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| 106 | #endif /* Py_ENABLE_SHARED */
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