Function SysFutexWait

Kernel/src/arch/x86_64/syscalls.cpp:1978–2007

//////////////////////// \brief SysFutexWait(futex, expected) Wait on a futex. Will wait on the futex if the value is equal to expected \param futex (void*) Futex pointer \param expected (int) Expected futex value \return 0 on success, error code on failure ////////////////////////

/// \return 0 on success, error code on failure
/////////////////////////////
long SysFutexWait(regs64_t* r){
	int* futex = reinterpret_cast<int*>(SC_ARG0(r));

	if(!Memory::CheckUsermodePointer(SC_ARG0(r), sizeof(int), Scheduler::GetCurrentProcess()->addressSpace)){
		return EFAULT;
	}

	int expected = static_cast<int>(SC_ARG1(r));

	if(*futex != expected){
		return 0;
	}

	process_t* currentProcess = Scheduler::GetCurrentProcess();

	Scheduler::FutexThreadBlocker* blocker = currentProcess->futexWaitQueue.get(reinterpret_cast<uintptr_t>(futex));

	if(!blocker){
		blocker = new Scheduler::FutexThreadBlocker();

		currentProcess->futexWaitQueue.insert(reinterpret_cast<uintptr_t>(futex), blocker);
	}

	releaseLock(&GetCPULocal()->currentThread->lock);

	lock_t temp = 0;
	Scheduler::BlockCurrentThread(*blocker, temp);

	return 0;
}

/////////////////////////////
/// \brief SysDup(fd) Duplicate a file descriptor