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106 lines
3.8 KiB
C
106 lines
3.8 KiB
C
/*
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Entry point for the Windows NT DLL.
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About the only reason for having this, is so initall() can automatically
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be called, removing that burden (and possible source of frustration if
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forgotten) from the programmer.
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*/
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#include "Python.h"
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#include "windows.h"
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#ifdef Py_ENABLE_SHARED
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char dllVersionBuffer[16] = ""; // a private buffer
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// Python Globals
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HMODULE PyWin_DLLhModule = NULL;
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const char *PyWin_DLLVersionString = dllVersionBuffer;
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// Windows "Activation Context" work:
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// Our .pyd extension modules are generally built without a manifest (ie,
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// those included with Python and those built with a default distutils.
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// This requires we perform some "activation context" magic when loading our
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// extensions. In summary:
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// * As our DLL loads we save the context being used.
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// * Before loading our extensions we re-activate our saved context.
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// * After extension load is complete we restore the old context.
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// As an added complication, this magic only works on XP or later - we simply
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// use the existence (or not) of the relevant function pointers from kernel32.
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// See bug 4566 (http://python.org/sf/4566) for more details.
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typedef BOOL (WINAPI * PFN_GETCURRENTACTCTX)(HANDLE *);
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typedef BOOL (WINAPI * PFN_ACTIVATEACTCTX)(HANDLE, ULONG_PTR *);
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typedef BOOL (WINAPI * PFN_DEACTIVATEACTCTX)(DWORD, ULONG_PTR);
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typedef BOOL (WINAPI * PFN_ADDREFACTCTX)(HANDLE);
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typedef BOOL (WINAPI * PFN_RELEASEACTCTX)(HANDLE);
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// locals and function pointers for this activation context magic.
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static HANDLE PyWin_DLLhActivationContext = NULL; // one day it might be public
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static PFN_GETCURRENTACTCTX pfnGetCurrentActCtx = NULL;
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static PFN_ACTIVATEACTCTX pfnActivateActCtx = NULL;
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static PFN_DEACTIVATEACTCTX pfnDeactivateActCtx = NULL;
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static PFN_ADDREFACTCTX pfnAddRefActCtx = NULL;
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static PFN_RELEASEACTCTX pfnReleaseActCtx = NULL;
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void _LoadActCtxPointers()
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{
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HINSTANCE hKernel32 = GetModuleHandleW(L"kernel32.dll");
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if (hKernel32)
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pfnGetCurrentActCtx = (PFN_GETCURRENTACTCTX) GetProcAddress(hKernel32, "GetCurrentActCtx");
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// If we can't load GetCurrentActCtx (ie, pre XP) , don't bother with the rest.
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if (pfnGetCurrentActCtx) {
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pfnActivateActCtx = (PFN_ACTIVATEACTCTX) GetProcAddress(hKernel32, "ActivateActCtx");
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pfnDeactivateActCtx = (PFN_DEACTIVATEACTCTX) GetProcAddress(hKernel32, "DeactivateActCtx");
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pfnAddRefActCtx = (PFN_ADDREFACTCTX) GetProcAddress(hKernel32, "AddRefActCtx");
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pfnReleaseActCtx = (PFN_RELEASEACTCTX) GetProcAddress(hKernel32, "ReleaseActCtx");
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}
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}
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ULONG_PTR _Py_ActivateActCtx()
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{
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ULONG_PTR ret = 0;
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if (PyWin_DLLhActivationContext && pfnActivateActCtx)
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if (!(*pfnActivateActCtx)(PyWin_DLLhActivationContext, &ret)) {
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OutputDebugString("Python failed to activate the activation context before loading a DLL\n");
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ret = 0; // no promise the failing function didn't change it!
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}
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return ret;
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}
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void _Py_DeactivateActCtx(ULONG_PTR cookie)
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{
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if (cookie && pfnDeactivateActCtx)
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if (!(*pfnDeactivateActCtx)(0, cookie))
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OutputDebugString("Python failed to de-activate the activation context\n");
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}
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BOOL WINAPI DllMain (HANDLE hInst,
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ULONG ul_reason_for_call,
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LPVOID lpReserved)
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{
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switch (ul_reason_for_call)
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{
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case DLL_PROCESS_ATTACH:
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PyWin_DLLhModule = hInst;
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// 1000 is a magic number I picked out of the air. Could do with a #define, I spose...
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LoadString(hInst, 1000, dllVersionBuffer, sizeof(dllVersionBuffer));
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// and capture our activation context for use when loading extensions.
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_LoadActCtxPointers();
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if (pfnGetCurrentActCtx && pfnAddRefActCtx)
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if ((*pfnGetCurrentActCtx)(&PyWin_DLLhActivationContext))
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if (!(*pfnAddRefActCtx)(PyWin_DLLhActivationContext))
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OutputDebugString("Python failed to load the default activation context\n");
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break;
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case DLL_PROCESS_DETACH:
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if (pfnReleaseActCtx)
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(*pfnReleaseActCtx)(PyWin_DLLhActivationContext);
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break;
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}
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return TRUE;
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}
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#endif /* Py_ENABLE_SHARED */
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