Method SetSignalMask

src/task/signal.cpp:190–228

}

auto TaskManager::SetSignalMask(int how, uint32_t set, uint32_t* oldset)
    -> Expected<void> {
  auto* current = GetCurrentTask();
  if (!current || !current->aux) {
    return std::unexpected(Error{ErrorCode::kTaskNoCurrentTask});
  }

  auto& signals = current->aux->signals;

  if (oldset) {
    *oldset = signals.blocked.load(std::memory_order_acquire);
  }

  // SIGKILL 和 SIGSTOP 不能被屏蔽
  uint32_t uncatchable_mask =
      (1U << signal_number::kSigKill) | (1U << signal_number::kSigStop);
  set &= ~uncatchable_mask;

  switch (how) {
    case signal_mask_op::kSigBlock:
      signals.blocked.fetch_or(set, std::memory_order_release);
      break;
    case signal_mask_op::kSigUnblock:
      signals.blocked.fetch_and(~set, std::memory_order_release);
      break;
    case signal_mask_op::kSigSetmask:
      signals.blocked.store(set, std::memory_order_release);
      break;
    default:
      return std::unexpected(Error{ErrorCode::kInvalidArgument});
  }

  signals.blocked.fetch_and(~uncatchable_mask, std::memory_order_release);

  klog::Debug("SetSignalMask: pid={} mask={:#x}", current->pid,
              signals.blocked.load(std::memory_order_acquire));

  return {};
}