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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;
}
}
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