int __except_handler3( struct _EXCEPTION_RECORD* pExceptionRecord, struct EXCEPTION_REGISTRATION* pRegistrationFrame, struct _CONTEXT* pContextRecord, void* pDispatcherContext ) { LONG filterFuncRet; LONG trylevel; EXCEPTION_POINTERS exceptPtrs; PSCOPETABLE pScopeTable; CLD // Clear the direction flag (make no assumptions!) // if neither the EXCEPTION_UNWINDING nor EXCEPTION_EXIT_UNWIND bit // is set... This is true the first time through the handler (the // non-unwinding case) if ( ! (pExceptionRecord->ExceptionFlags & (EXCEPTION_UNWINDING | EXCEPTION_EXIT_UNWIND) ) ) { // Build the EXCEPTION_POINTERS structure on the stack exceptPtrs.ExceptionRecord = pExceptionRecord; exceptPtrs.ContextRecord = pContextRecord; // Put the pointer to the EXCEPTION_POINTERS 4 bytes below the // establisher frame. See ASM code for GetExceptionInformation *(PDWORD)((PBYTE)pRegistrationFrame - 4) = &exceptPtrs; // Get initial "trylevel" value trylevel = pRegistrationFrame->trylevel // Get a pointer to the scopetable array scopeTable = pRegistrationFrame->scopetable; search_for_handler: if ( pRegistrationFrame->trylevel != TRYLEVEL_NONE ) { if ( pRegistrationFrame->scopetable[trylevel].lpfnFilter ) { PUSH EBP // Save this frame EBP // !!!Very Important!!! Switch to original EBP. This is // what allows all locals in the frame to have the same // value as before the exception occurred. EBP = &pRegistrationFrame->_ebp // Call the filter function filterFuncRet = scopetable[trylevel].lpfnFilter(); POP EBP // Restore handler frame EBP if ( filterFuncRet != EXCEPTION_CONTINUE_SEARCH ) { if ( filterFuncRet < 0 ) // EXCEPTION_CONTINUE_EXECUTION return ExceptionContinueExecution; // If we get here, EXCEPTION_EXECUTE_HANDLER was specified scopetable == pRegistrationFrame->scopetable // Does the actual OS cleanup of registration frames // Causes this function to recurse __global_unwind2( pRegistrationFrame ); // Once we get here, everything is all cleaned up, except // for the last frame, where we'll continue execution EBP = &pRegistrationFrame->_ebp __local_unwind2( pRegistrationFrame, trylevel ); // NLG == "non-local-goto" (setjmp/longjmp stuff) __NLG_Notify( 1 ); // EAX == scopetable->lpfnHandler // Set the current trylevel to whatever SCOPETABLE entry // was being used when a handler was found pRegistrationFrame->trylevel = scopetable->previousTryLevel; // Call the _except {} block. Never returns. pRegistrationFrame->scopetable[trylevel].lpfnHandler(); } } scopeTable = pRegistrationFrame->scopetable; trylevel = scopeTable->previousTryLevel goto search_for_handler; } else // trylevel == TRYLEVEL_NONE { retvalue == DISPOSITION_CONTINUE_SEARCH; } } else // EXCEPTION_UNWINDING or EXCEPTION_EXIT_UNWIND flags are set { PUSH EBP // Save EBP EBP = pRegistrationFrame->_ebp // Set EBP for __local_unwind2 __local_unwind2( pRegistrationFrame, TRYLEVEL_NONE ) POP EBP // Restore EBP retvalue == DISPOSITION_CONTINUE_SEARCH; } }