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title "User Mode Dispatcher Code";++;; Copyright (c) 1989 Microsoft Corporation;; Module Name:;; userdisp.asm;; Abstract:;; The module contains procedures to do user mode dispatching; ("trampolining") of user apcs and user exceptions.;; Author:;; Bryan M Willman (bryanwi) 31-Aug-90;; Environment:;; User mode.;; Revision History:;;--.386p .xlistinclude ks386.incinclude callconv.inc ; calling convention macros .list
ifndef WX86_i386 EXTRNP _ZwCallbackReturn,3endif
EXTRNP _ZwContinue,2 EXTRNP _RtlDispatchException,2 EXTRNP _RtlRaiseStatus,1 EXTRNP _ZwRaiseException,3 EXTRNP _RtlRaiseException,1;; Exception record size definition.;
ExceptionRecordSize = (ErNumberParameters + 4 + 3) AND 0fffffffcH ;
page ,132_TEXT SEGMENT DWORD PUBLIC 'CODE' ASSUME DS:FLAT, ES:FLAT, SS:NOTHING, FS:NOTHING, GS:NOTHING
ifndef WX86_i386 page subttl "User APC Dispatcher";++;; VOID; KiUserApcDispatcher (; IN PKNORMAL_ROUTINE NormalRoutine,; IN PVOID NormalContext,; IN PVOID SystemArgument1,; IN PVOID SystemArgument2,; IN CONTEXT ContinueContext; );; Routine Description:;; This routine is entered on return from kernel mode to deliver an APC; in user mode. The context frame for this routine was built when the; APC interrupt was processed and contains the entire machine state of; the current thread. The specified APC routine is called and then the; machine state is restored and execution is continued.;; Arguments:;; NormalRoutine - Supplies that address of the function that is to be called.;; NormalContext] - Supplies the normal context parameter that was specified; when the APC was initialized.;; SystemArgument1 - Supplies the first argument that was provied by the; executive when the APC was queued.;; SystemArgument2 - Supplies the second argument that was provided by; the executive when the APC was queued.;; ContinueContext - Context record to pass to Continue call.;;; Return Value:;; None.;;--cPublicProc _KiUserApcDispatcher ,5
lea edi, [esp+16] ; (edi)->context frame pop eax ; (eax)->specified function call eax ; call the specified function
; 1 - set alert argument true; ebp - addr of context frame; execute system service to continue stdCall _ZwContinue, <edi, 1>
stdENDP _KiUserApcDispatcher
page subttl "User Callback Dispatcher";++;; VOID; KiUserCallbackDispatcher (; IN ULONG ApiNumber,; IN PVOID InputBuffer,; IN ULONG INputLength; );; Routine Description:;; This routine is entered on a callout from kernel mode to execute a; user mode callback function. All arguments for this function have; been placed on the stack.;; Arguments:;; ApiNumber - Supplies the API number of the callback function that is; executed.;; InputBuffer - Supplies a pointer to the input buffer.;; InputLength - Supplies the input buffer length.;; Return Value:;; This function returns to kernel mode.;;--cPublicProc _KiUserCallbackDispatcher, 3.FPO (0, 0, 0, 0, 0, 0)
add esp,4 ; skip over return address pop edx ; get address of callback function
; get peb pointer from teb mov eax,fs:[PcTeb] mov eax,[eax].TebPeb mov eax,[eax].PebKernelCallbackTable ; get address of callback table
call [eax+edx*4] ; call specified function
;; If a return from the callback function occurs, then the output buffer; address and length are returned as NULL.;
xor ecx,ecx ; clear output buffer addressifdef BUILD_WOW6432 stdCall _ZwCallbackReturn, <ecx, ecx, eax>else xor edx,edx ; clear output buffer length int 02bH ; return from callbackendif int 3 ; break if return occurs
stdENDP _KiUserCallbackDispatcher
endif ;; ndef WX86_i386
page subttl "User Exception Dispatcher";++;; VOID; KiUserExceptionDispatcher (; IN PEXCEPTION_RECORD ExceptionRecord,; IN PCONTEXT ContextRecord; );; Routine Description:;; This routine is entered on return from kernel mode to dispatch a user; mode exception. If a frame based handler handles the exception, then; the execution is continued. Else last chance processing is performed.;; NOTE: This procedure is not called, but rather dispatched to.; It depends on there not being a return address on the stack; (assumption w.r.t. argument offsets.);; Arguments:;; ExceptionRecord (esp+0) - Supplies a pointer to an exception record.;; ContextRecord (esp+4) - Supplies a pointer to a context frame.;; Return Value:;; None.;;--
cPublicProc _KiUserExceptionDispatcher ,2.FPO (0, 2, 0, 0, 0, 0)
mov ecx, [esp+4] ; (ecx)->context record mov ebx, [esp] ; (ebx)->exception record
; attempt to dispatch the exception stdCall _RtlDispatchException, <ebx, ecx>
;; If the return status is TRUE, then the exception was handled and execution; should be continued with the NtContinue service in case the context was; changed. If the return statusn is FALSE, then the exception was not handled; and ZwRaiseException is called to perform last chance exception processing.;
or al,al je short kued10
;; Continue execution.; pop ebx ; (ebx)->exception record pop ecx ; (ecx)->context record
; continue execution stdCall _ZwContinue, <ecx, 0> jmp short kued20 ; join common code
;; Last chance processing.;; (esp+0) = ExceptionRecord; (esp+4) = ContextRecord;
kued10: pop ebx ; (ebx)->exception record pop ecx ; (ecx)->context record
; ecx - context record; ebx - exception record; perform last chance processiong stdCall _ZwRaiseException, <ebx, ecx, 0>
;; Common code for nonsuccessful completion of the continue or raiseexception; services. Use the return status as the exception code, set noncontinuable; exception and attempt to raise another exception. Note the stack grows; and eventually this loop will end.;
.FPO(0, 0, 0, 0, 0, 0)
kued20: add esp, -ExceptionRecordSize ; allocate stack space mov [esp]+ErExceptionCode, eax ; set exception code mov dword ptr [esp]+ErExceptionFlags, EXCEPTION_NONCONTINUABLE mov [esp]+ErExceptionRecord,ebx ; set associated exception record mov dword ptr [esp]+ErNumberParameters, 0 ; set number of parameters; esp - addr of exception record stdCall _RtlRaiseException, <esp>; never return stdRET _KiUserExceptionDispatcher
stdENDP _KiUserExceptionDispatcher
page subttl "Raise User Exception Dispatcher"ifndef WX86_i386;++;; NTSTATUS; KiUserExceptionDispatcher (; IN PVOID ReturnAddress; IN NTSTATUS ExceptionCode; );; Routine Description:;; This routine is entered on return from kernel mode to raise a user; mode exception.;; NOTE: This procedure is not called, but rather dispatched to.;; The exception code to be raised is passed in the TEB.;; Arguments:;; ExceptionCode (TEB->ExceptionCode) - Supplies the exception code to be raised;; Return Value:;; The exception code that was raised.;;--
cPublicProc _KiRaiseUserExceptionDispatcher
push ebp ; make the debugger happy mov ebp, esp sub esp, ExceptionRecordLength ; allocate exception record mov [esp].ErExceptionAddress, eax ; set exception address mov eax,fs:[PcTeb] ; get exception code to be raised mov eax,[eax].TbExceptionCode ; mov [esp].ErExceptionCode, eax ; store exception code mov [esp].ErExceptionFlags, 0 ; set exception flags mov [esp].ErExceptionRecord, 0 ; set exception record mov [esp].ErNumberParameters, 0 ; set number of parameters; raise the exception stdCall _RtlRaiseException, <esp> mov eax, [esp].ErExceptionCode mov esp,ebp pop ebp ; restore return code ret
stdENDP _KiRaiseUserExceptionDispatcherendif ;; ndef WX86_i386
_TEXT ENDS
END
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