Method SendSignal

src/task/signal.cpp:13–71

#include "task_messages.hpp"

auto TaskManager::SendSignal(Pid pid, int signum) -> Expected<void> {
  if (!SignalState::IsValid(signum)) {
    return std::unexpected(Error{ErrorCode::kSignalInvalidNumber});
  }

  // 查找目标任务
  TaskControlBlock* target = nullptr;
  {
    LockGuard<SpinLock> lock_guard(task_table_lock_);
    auto it = task_table_.find(pid);
    if (it == task_table_.end()) {
      return std::unexpected(Error{ErrorCode::kSignalTaskNotFound});
    }
    target = it->second.get();
  }

  if (!target || !target->aux) {
    return std::unexpected(Error{ErrorCode::kSignalTaskNotFound});
  }

  target->aux->signals.SetPending(signum);

  klog::Debug("SendSignal: signal {} ({}) sent to pid={}",
              SignalState::GetSignalName(signum), signum, pid);

  // SIGKILL 和 SIGCONT 需要立即唤醒阻塞/睡眠的任务
  bool needs_wake =
      (signum == signal_number::kSigKill || signum == signal_number::kSigCont);

  // 如果信号未被屏蔽，也需要唤醒
  if (!needs_wake &&
      !(target->aux->signals.blocked.load(std::memory_order_acquire) &
        (1U << signum))) {
    auto status = target->GetStatus();
    if (status == TaskStatus::kBlocked || status == TaskStatus::kSleeping) {
      needs_wake = true;
    }
  }

  if (needs_wake) {
    auto status = target->GetStatus();

    if (status == TaskStatus::kBlocked) {
      auto resource_id = target->aux->blocked_on;
      if (static_cast<bool>(resource_id)) {
        Wakeup(resource_id);
        klog::Debug("SendSignal: woke blocked task pid={} for signal {}", pid,
                    SignalState::GetSignalName(signum));
      }
    } else if (status == TaskStatus::kSleeping) {
      // Expedite wake: set wake_tick to 0 so next TickUpdate wakes it.
      // Note: single aligned 64-bit store is atomic on 64-bit platforms.
      target->sched_info.wake_tick = 0;
      klog::Debug("SendSignal: expedited sleep wakeup for pid={}", pid);
    }
  }

  return {};