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