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TitanEngine
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fix multi-thread breakpoint deletion race condition

This commit is contained in:
AzuLX 2026-01-05 15:47:03 +00:00
parent f6c9698fd7
commit 8072f96a26
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GPG Key ID: BED7E7DC23A637BC
1 changed files with 29 additions and 4 deletions
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33
TitanEngine/TitanEngine.Debugger.DebugLoop.cpp
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@ -589,11 +589,36 @@ __declspec(dllexport) void TITCALL DebugLoop()
{
if(DebugAttachedToProcess || !FirstBPX) //program generated a breakpoint exception
{
DBGCode = DBG_EXCEPTION_NOT_HANDLED;
if(DBGCustomHandler->chBreakPoint != NULL)
ULONG_PTR exceptionAddress = (ULONG_PTR)DBGEvent.u.Exception.ExceptionRecord.ExceptionAddress;
unsigned char currentByte = 0xCC;
MemoryReadSafe(dbgProcessInformation.hProcess, (void*)exceptionAddress, &currentByte, 1, nullptr);
if(currentByte != 0xCC)
{
myCustomHandler = (fCustomHandler)((LPVOID)DBGCustomHandler->chBreakPoint);
myCustomHandler(&DBGEvent.u.Exception.ExceptionRecord);
//breakpoint was deleted - the byte is no longer 0xCC
//reset IP to exception address and continue gracefully
DBGCode = DBG_CONTINUE;
hActiveThread = EngineOpenThread(THREAD_GETSETSUSPEND, false, DBGEvent.dwThreadId);
CONTEXT myDBGContext;
myDBGContext.ContextFlags = ContextControlFlags;
GetThreadContext(hActiveThread, &myDBGContext);
#if defined(_WIN64)
myDBGContext.Rip = exceptionAddress;
#else
myDBGContext.Eip = (DWORD)exceptionAddress;
#endif
SetThreadContext(hActiveThread, &myDBGContext);
EngineCloseHandle(hActiveThread);
}
else
{
//byte is still 0xCC - this is a real int3 in the original code!!
DBGCode = DBG_EXCEPTION_NOT_HANDLED;
if(DBGCustomHandler->chBreakPoint != NULL)
{
myCustomHandler = (fCustomHandler)((LPVOID)DBGCustomHandler->chBreakPoint);
myCustomHandler(&DBGEvent.u.Exception.ExceptionRecord);
}
}
}
else //system breakpoint