// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.

#ifndef SRC_NODE_WATCHDOG_H_
#define SRC_NODE_WATCHDOG_H_

#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#include <memory>
#include <string_view>
#include <vector>
#include "handle_wrap.h"
#include "memory_tracker-inl.h"
#include "node_mutex.h"
#include "uv.h"
#include "v8.h"

#ifdef __POSIX__
#include <pthread.h>
#endif

namespace node {

enum class SignalPropagation {
  kContinuePropagation,
  kStopPropagation,
};

class Watchdog {
 public:
  explicit Watchdog(v8::Isolate* isolate,
                    uint64_t ms,
                    bool* timed_out = nullptr);
  ~Watchdog();
  v8::Isolate* isolate() { return isolate_; }

 private:
  Watchdog(const Watchdog&) = delete;
  Watchdog& operator=(const Watchdog&) = delete;
  Watchdog(Watchdog&&) = delete;
  Watchdog& operator=(Watchdog&&) = delete;

  static void Run(void* arg);
  static void Timer(uv_timer_t* timer);

  v8::Isolate* isolate_;
  uv_thread_t thread_;
  uv_loop_t loop_;
  uv_async_t async_;
  uv_timer_t timer_;
  bool* timed_out_;
};

// How long the main thread has to respond to --process-timeout, and Worker
// threads to provide their part of the report. A thread that does not respond
// is most likely blocked in a synchronous native call.
constexpr uint64_t kProcessTimeoutResponseGraceMs = 2000;
// The trigger of the report written by --report-on-process-timeout.
constexpr std::string_view kProcessTimeoutReportTrigger = "ProcessTimeout";

// Implements --process-timeout.
//
// A dedicated thread waits until the configured duration has elapsed since the
// process started. It then interrupts the main thread, which works both while
// JavaScript is running and while the event loop is waiting for events, to
// print why the process was still running and to exit with
// ExitCode::kProcessTimeout. If the main thread does not respond, for example
// because it is blocked in a synchronous native call, or does not finish
// exiting in time, the watchdog thread forces the process to exit on its own.
class ProcessTimeoutWatchdog {
 public:
  // Starts the watchdog for the main thread's Environment. Returns nullptr if
  // --process-timeout was not passed, or if this process only supervises the
  // runs of the application (--watch), in which case each run applies the
  // timeout on its own.
  static std::unique_ptr<ProcessTimeoutWatchdog> MaybeStart(Environment* env);

  // Whether --process-timeout is in effect for this process. Thread-safe.
  static bool IsEnabled();

  // Must be called once the event loop has stopped and before the Environment
  // is freed. From here on the watchdog no longer interrupts the main thread,
  // but still forces the process to exit if it is alive past the deadline.
  void OnEnvironmentStopping();

  // Disarms the watchdog and joins its thread.
  ~ProcessTimeoutWatchdog();

  ProcessTimeoutWatchdog(const ProcessTimeoutWatchdog&) = delete;
  ProcessTimeoutWatchdog& operator=(const ProcessTimeoutWatchdog&) = delete;
  ProcessTimeoutWatchdog(ProcessTimeoutWatchdog&&) = delete;
  ProcessTimeoutWatchdog& operator=(ProcessTimeoutWatchdog&&) = delete;

 private:
  struct State;

  ProcessTimeoutWatchdog(Environment* env, std::shared_ptr<State> state);

  static void Run(void* arg);
  static void OnTimeout(Environment* env, const std::shared_ptr<State>& state);

  Environment* env_;
  // Shared with the interrupt callback, which may outlive this object.
  std::shared_ptr<State> state_;
  uv_thread_t thread_;
};

class SigintWatchdogBase {
 public:
  virtual ~SigintWatchdogBase() = default;
  virtual SignalPropagation HandleSigint() = 0;
};

class SigintWatchdog : public SigintWatchdogBase {
 public:
  explicit SigintWatchdog(v8::Isolate* isolate,
                          bool* received_signal = nullptr);
  ~SigintWatchdog();
  v8::Isolate* isolate() { return isolate_; }
  SignalPropagation HandleSigint() override;

 private:
  SigintWatchdog(const SigintWatchdog&) = delete;
  SigintWatchdog& operator=(const SigintWatchdog&) = delete;
  SigintWatchdog(SigintWatchdog&&) = delete;
  SigintWatchdog& operator=(SigintWatchdog&&) = delete;

  v8::Isolate* isolate_;
  bool* received_signal_;
};

class TraceSigintWatchdog : public HandleWrap, public SigintWatchdogBase {
 public:
  static void Init(Environment* env, v8::Local<v8::Object> target);
  static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Start(const v8::FunctionCallbackInfo<v8::Value>& args);
  static void Stop(const v8::FunctionCallbackInfo<v8::Value>& args);

  SignalPropagation HandleSigint() override;

  inline void MemoryInfo(node::MemoryTracker* tracker) const override {
    tracker->TrackInlineField("handle_", handle_);
  }
  SET_MEMORY_INFO_NAME(TraceSigintWatchdog)
  SET_SELF_SIZE(TraceSigintWatchdog)

 private:
  enum class SignalFlags { None, FromIdle, FromInterrupt };

  TraceSigintWatchdog(Environment* env, v8::Local<v8::Object> object);
  void HandleInterrupt();

  bool interrupting = false;
  uv_async_t handle_;
  SignalFlags signal_flag_ = SignalFlags::None;
};

class SigintWatchdogHelper {
 public:
  static SigintWatchdogHelper* GetInstance() { return &instance; }
  static Mutex& GetInstanceActionMutex() { return instance_action_mutex_; }
  void Register(SigintWatchdogBase* watchdog);
  void Unregister(SigintWatchdogBase* watchdog);
  bool HasPendingSignal();

  int Start();
  bool Stop();

 private:
  SigintWatchdogHelper();
  ~SigintWatchdogHelper();

  static bool InformWatchdogsAboutSignal();
  static SigintWatchdogHelper instance;
  static Mutex instance_action_mutex_;

  int start_stop_count_;

  Mutex mutex_;
  Mutex list_mutex_;
  std::vector<SigintWatchdogBase*> watchdogs_;
  bool has_pending_signal_;

#ifdef __POSIX__
  pthread_t thread_;
  uv_sem_t sem_;
  bool has_running_thread_;
  bool stopping_;

  static void* RunSigintWatchdog(void* arg);
  static void HandleSignal(int signum, siginfo_t* info, void* ucontext);
#else
  bool watchdog_disabled_;
  static BOOL WINAPI WinCtrlCHandlerRoutine(DWORD dwCtrlType);
#endif
};

}  // namespace node

#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS

#endif  // SRC_NODE_WATCHDOG_H_