--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/kernel/eka/common/win32/seh.cpp	Mon Oct 19 15:55:17 2009 +0100
@@ -0,0 +1,252 @@
+// Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).
+// All rights reserved.
+// This component and the accompanying materials are made available
+// under the terms of the License "Eclipse Public License v1.0"
+// which accompanies this distribution, and is available
+// at the URL "http://www.eclipse.org/legal/epl-v10.html".
+//
+// Initial Contributors:
+// Nokia Corporation - initial contribution.
+//
+// Contributors:
+//
+// Description:
+// e32\common\win32\seh.cpp
+// 
+//
+
+#include "seh.h"
+
+// Fill in the blank types for TWin32SEHTrap
+#define __WIN32_SEH_TYPES_KNOWN__
+#define __UnknownWindowsType1 EXCEPTION_RECORD
+#define __UnknownWindowsType2 CONTEXT
+
+// Pretend we're tools to avoid clashes with Win32 headers
+#define __TOOLS__
+#define __IN_SEH_CPP__
+#include <e32cmn.h>
+#include <e32cmn_private.h>
+
+#include <emulator.h>
+
+#include <e32panic.h>
+GLREF_C void Panic(TCdtPanic);
+
+// magic value denoting the end of the SEH handler list
+static const TWin32SEHTrap* const KFencePost = (TWin32SEHTrap*)-1;
+
+//
+// Class TWin32SEHTrap
+//
+
+#ifdef __KERNEL_MODE__
+
+extern DWORD CallFinalSEHHandler(EXCEPTION_RECORD* aException, CONTEXT* aContext)
+	{
+	// Get the final SEH entry on the chain
+	TWin32SEHTrap* finalHandler = TWin32SEHTrap::IterateForFinal();
+
+	// Call the handler - ignoring return value
+	(void)(*finalHandler->ExceptionHandler())(aException, finalHandler, aContext);
+
+	// Explicitly tell Win32 the exception has been handled
+	return ExceptionContinueExecution;
+	}
+
+TWin32SEHTrap* TWin32SEHTrap::IterateForFinal()
+	{
+	TWin32SEHTrap* p = (TWin32SEHTrap*)Tib()->ExceptionList;
+
+	// Iterate through the SEH chain to find the final SEH record that we wish to skip to
+    for (; p && p!=KFencePost && p->iPrevExceptionRegistrationRecord!=KFencePost; p=p->iPrevExceptionRegistrationRecord)
+		{}
+	return p;
+	}
+
+TWin32SEHExceptionHandler* TWin32SEHTrap::ExceptionHandler()
+	{
+	return iExceptionHandler;
+	}
+
+#else // !__KERNEL_MODE__
+#include <u32exec.h>
+
+
+extern "C" void trap_check(TWin32SEHTrap* a)
+	{
+	TWin32SEHTrap* p = a->iPrevExceptionRegistrationRecord;
+	if (p && p!=KFencePost && a->iExceptionHandler == p->iExceptionHandler && a->iExceptionHandler == &TWin32SEHTrap::ExceptionHandler)
+		Exec::PushTrapFrame((TTrap*)p);
+	else
+		Exec::PushTrapFrame(0);
+	}
+
+extern "C" void untrap_check()
+	{
+	// search back for consecutive TWin32SEHTrap and remember the second one
+	TWin32SEHTrap* p = (TWin32SEHTrap*)Tib()->ExceptionList;
+	TWin32SEHTrap* q = 0;
+	TWin32SEHTrap* s = 0;
+	if (p && p!=KFencePost)
+		{
+		for(;;)
+			{
+			q = p->iPrevExceptionRegistrationRecord;
+			if (!q || q==KFencePost)
+				break;
+			if (p->iExceptionHandler == &TWin32SEHTrap::ExceptionHandler && q->iExceptionHandler == &TWin32SEHTrap::ExceptionHandler)
+				{
+				s = q;
+				break;
+				}
+			p = q;
+			}
+		}
+	Exec::PushTrapFrame((TTrap*)s);
+	}
+
+// Use assembler to ensure no extra SEH frame is created by the compiler
+UEXPORT_C __NAKED__ void TWin32SEHTrap::Trap()
+	{
+	_asm mov eax, fs:[0]
+	_asm mov [ecx], eax
+	_asm mov fs:[0], ecx
+	_asm push ecx
+	_asm call trap_check
+	_asm pop ecx
+	_asm ret
+	}
+
+extern "C" void panic_chain_corrupt()
+	{
+	Panic(EWin32SEHChainCorrupt);
+	}
+
+// Use assembler to ensure no extra SEH frame is created by the compiler
+UEXPORT_C __NAKED__ void TWin32SEHTrap::UnTrap()
+	{
+	_asm mov eax, fs:[0]
+	_asm cmp eax, ecx
+	_asm ja untrap_0
+	_asm jb untrap_error
+	_asm mov eax, [ecx]
+	_asm mov fs:[0], eax
+	_asm xor eax, eax
+	_asm mov [ecx], eax
+	_asm call untrap_check
+untrap_0:
+	_asm ret
+untrap_error:
+	_asm jmp panic_chain_corrupt
+	}
+
+UEXPORT_C TWin32SEHTrap::TWin32SEHTrap()
+	:	iPrevExceptionRegistrationRecord(NULL),
+		iExceptionHandler(&ExceptionHandler)
+	{
+	}
+
+// Handler called whilst Win32 is walking the SEH chain
+DWORD TWin32SEHTrap::ExceptionHandler(EXCEPTION_RECORD* aException, TWin32SEHTrap* /*aRegistrationRecord*/, CONTEXT* aContext)
+	{
+	if (aException->ExceptionCode != EXCEPTION_MSCPP)
+		{
+		return Emulator::Win32SEHException(aException, aContext);
+		}
+	else
+		{
+		return ExceptionContinueSearch;
+		}
+	}
+
+#if defined(__LEAVE_EQUALS_THROW__) && defined(__WINS__)
+extern "C" TWin32SEHTrap* pop_trap_frame()
+	{
+	return (TWin32SEHTrap*)Exec::PopTrapFrame();
+	}
+
+extern "C" void leave_end()
+	{
+	Exec::LeaveEnd();
+	}
+
+
+EXPORT_C __NAKED__ TInt XLeaveException::GetReason() const
+	{
+	_asm push ecx
+	_asm call pop_trap_frame
+	_asm test eax, eax
+	_asm jz no_nested_trap
+
+	// eax points to TWin32SEHTrap to be restored
+	// if current exception record is above eax on the stack just restore eax
+	_asm cmp eax, esp
+	_asm jbe nested_trap_error
+	_asm mov edx, fs:[0]
+	_asm cmp eax, edx
+	_asm ja nested_trap_insert_in_middle
+	_asm je no_nested_trap	// we haven't been unwound after all
+
+	// check we eventually reach current exception record from eax
+	_asm mov ecx, eax
+	_asm mov edx, [eax+4]	// &TWin32SEHTrap::ExceptionHandler
+nested_trap_check:
+	_asm mov ecx, [ecx]
+	_asm cmp ecx, 0
+	_asm jz nested_trap_error
+	_asm cmp ecx, 0ffffffffh
+	_asm jz nested_trap_error
+	_asm cmp ecx, fs:[0]
+	_asm jz nested_trap_check_ok
+	_asm cmp edx, [ecx+4]	// all intervening entries should be TWin32SEHTrap
+	_asm jz nested_trap_check
+	_asm jmp nested_trap_error
+
+	// other SEH handlers have been added after we were unwound so we need to insert eax 'in the middle'
+nested_trap_insert_in_middle:
+	_asm cmp eax, [edx]
+	_asm je no_nested_trap	// eax is still in the chain
+	_asm jb nested_trap_insert_in_middle_found
+	_asm mov edx, [edx]
+	_asm jmp nested_trap_insert_in_middle
+
+nested_trap_insert_in_middle_found:
+	_asm mov ecx, [edx]		// first SEH above eax on stack
+	_asm cmp ecx, 0ffffffffh
+	_asm je nested_trap_error	// reached end of SEH list
+	_asm push edx
+
+	// ECX should be reachable from EAX
+	_asm mov edx, eax
+nested_trap_insert_in_middle_check:
+	_asm mov edx, [edx]
+	_asm cmp ecx, edx
+	_asm je nested_trap_insert_in_middle_ok
+	_asm cmp edx, 0ffffffffh
+	_asm je nested_trap_error	// reached end of SEH list
+	_asm test edx, edx
+	_asm jnz nested_trap_insert_in_middle_check
+	_asm jmp nested_trap_error
+
+nested_trap_insert_in_middle_ok:
+	_asm pop edx
+	_asm mov [edx], eax		// insert eax back into chain
+	_asm jmp no_nested_trap
+
+nested_trap_check_ok:
+	_asm mov fs:[0], eax	// reinstall nested trap SEH handlers
+
+no_nested_trap:
+	_asm call untrap_check	// check for other nested TRAPs
+	_asm call leave_end
+	_asm pop ecx
+	_asm mov eax, [ecx]XLeaveException.iR
+	_asm ret
+
+nested_trap_error:
+	_asm jmp panic_chain_corrupt
+	}
+#endif	// defined(__LEAVE_EQUALS_THROW__) && defined(__WINS__)
+
+#endif //__KERNEL_MODE__