Commit 8ec5ffef2ecabd2474706b11e0238e8fca40b800
2020-07-14T21:14:56
Replace VirtualQueryEx() call by GetModuleHandleExA() call Usage of VirtualQueryEx() call is needed for retrieving HMODULE of passed function address and it is just an undocumented hack. Based on @rhabacker's tests it is unstable and does not work correctly. https://github.com/dlfcn-win32/dlfcn-win32/pull/72#issuecomment-656581418 So replace VirtualQueryEx() call by standard GetModuleHandleExA() function with special GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS flag which should do the same thing but it is documented and it is working correctly.
diff --git a/dlfcn.c b/dlfcn.c
index 01e878b..a45a619 100644
--- a/dlfcn.c
+++ b/dlfcn.c
@@ -369,24 +369,10 @@ void *dlsym( void *handle, const char *name )
* The next object is the one found upon the application of a load
* order symbol resolution algorithm. To get caller function of dlsym()
* use _ReturnAddress() intrinsic. To get HMODULE of caller function
- * use undocumented hack from https://stackoverflow.com/a/2396380
- * The HMODULE of a DLL is the same value as the module's base address.
+ * use standard GetModuleHandleExA() function.
*/
- MEMORY_BASIC_INFORMATION info;
- size_t sLen;
- sLen = VirtualQueryEx( hCurrentProc, _ReturnAddress(), &info, sizeof( info ) );
- if( sLen != sizeof( info ) )
- {
- if( sLen != 0 )
- SetLastError( ERROR_INVALID_PARAMETER );
+ if( !GetModuleHandleExA( GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT, (LPCSTR) _ReturnAddress( ), &hCaller ) )
goto end;
- }
- hCaller = (HMODULE) info.AllocationBase;
- if( !hCaller )
- {
- SetLastError( ERROR_INVALID_PARAMETER );
- goto end;
- }
}
if( handle != RTLD_NEXT )