instance.cc

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

                                  is already started
*/

int Instance::start()
{
  /* clear crash flag */
  pthread_mutex_lock(&LOCK_instance);
  crashed= 0;
  pthread_mutex_unlock(&LOCK_instance);


  if (!is_running())
  {
    remove_pid();

    /*
      No need to monitor this thread in the Thread_registry, as all
      instances are to be stopped during shutdown.
    */
    pthread_t proxy_thd_id;
    pthread_attr_t proxy_thd_attr;
    int rc;

    pthread_attr_init(&proxy_thd_attr);
    pthread_attr_setdetachstate(&proxy_thd_attr, PTHREAD_CREATE_DETACHED);
    rc= pthread_create(&proxy_thd_id, &proxy_thd_attr, proxy,
                       this);
    pthread_attr_destroy(&proxy_thd_attr);
    if (rc)
    {
      log_error("Instance::start(): pthread_create(proxy) failed");
      return ER_CANNOT_START_INSTANCE;
    }

    return 0;
  }

  /* the instance is started already */
  return ER_INSTANCE_ALREADY_STARTED;
}

/*
  The method sets the crash flag and wakes all waiters on
  COND_instance_stopped and COND_guardian

  SYNOPSYS
    set_crash_flag_n_wake_all()

  DESCRIPTION
    The method is called when an instance is crashed or terminated.
    In the former case it might indicate that guardian probably should
    restart it.

  RETURN
    Function returns no value
*/

void Instance::set_crash_flag_n_wake_all()
{
  /* set instance state to crashed */
  pthread_mutex_lock(&LOCK_instance);
  crashed= 1;
  pthread_mutex_unlock(&LOCK_instance);

  /*
    Wake connection threads waiting for an instance to stop. This
    is needed if a user issued command to stop an instance via
    mysql connection. This is not the case if Guardian stop the thread.
  */
  pthread_cond_signal(&COND_instance_stopped);
  /* wake guardian */
  pthread_cond_signal(&instance_map->guardian->COND_guardian);
}



Instance::Instance(): crashed(0)
{
  pthread_mutex_init(&LOCK_instance, 0);
  pthread_cond_init(&COND_instance_stopped, 0);
}


Instance::~Instance()
{
  pthread_cond_destroy(&COND_instance_stopped);
  pthread_mutex_destroy(&LOCK_instance);
}


int Instance::is_crashed()
{
  int val;
  pthread_mutex_lock(&LOCK_instance);
  val= crashed;
  pthread_mutex_unlock(&LOCK_instance);
  return val;
}


bool Instance::is_running()
{
  MYSQL mysql;
  uint port= 0;
  const char *socket= NULL;
  static const char *password= "check_connection";
  static const char *username= "MySQL_Instance_Manager";
  static const char *access_denied_message= "Access denied for user";
  bool return_val;

  if (options.mysqld_port)
    port= options.mysqld_port_val;

  if (options.mysqld_socket)
    socket= strchr(options.mysqld_socket, '=') + 1;

  /* no port was specified => instance falled back to default value */
  if (!options.mysqld_port && !options.mysqld_socket)
    port= SERVER_DEFAULT_PORT;

  pthread_mutex_lock(&LOCK_instance);

  mysql_init(&mysql);
  /* try to connect to a server with a fake username/password pair */
  if (mysql_real_connect(&mysql, LOCAL_HOST, username,
                         password,
                         NullS, port,
                         socket, 0))
  {
    /*
      We have successfully connected to the server using fake
      username/password. Write a warning to the logfile.
    */
    log_info("The Instance Manager was able to log into you server \
             with faked compiled-in password while checking server status. \
             Looks like something is wrong.");
    pthread_mutex_unlock(&LOCK_instance);
    return_val= TRUE;                           /* server is alive */
  }
  else
    return_val= test(!strncmp(access_denied_message, mysql_error(&mysql),
                              sizeof(access_denied_message) - 1));

  mysql_close(&mysql);
  pthread_mutex_unlock(&LOCK_instance);

  return return_val;
}


/*
  Stop an instance.

  SYNOPSYS
    stop()

  RETURN:
    0                            ok
    ER_INSTANCE_IS_NOT_STARTED   Looks like the instance it is not started
    ER_STOP_INSTANCE             mysql_shutdown reported an error
*/

int Instance::stop()
{
  struct timespec timeout;
  uint waitchild= (uint)  DEFAULT_SHUTDOWN_DELAY;

  if (options.shutdown_delay_val)
    waitchild= options.shutdown_delay_val;

  kill_instance(SIGTERM);
  /* sleep on condition to wait for SIGCHLD */

  timeout.tv_sec= time(NULL) + waitchild;
  timeout.tv_nsec= 0;
  if (pthread_mutex_lock(&LOCK_instance))
    goto err;

  while (options.get_pid() != 0)              /* while server isn't stopped */
  {
    int status;

    status= pthread_cond_timedwait(&COND_instance_stopped,
                                   &LOCK_instance,
                                   &timeout);
    if (status == ETIMEDOUT || status == ETIME)
      break;
  }

  pthread_mutex_unlock(&LOCK_instance);

  kill_instance(SIGKILL);

  return 0;

  return ER_INSTANCE_IS_NOT_STARTED;
err:
  return ER_STOP_INSTANCE;
}

#ifdef __WIN__

BOOL SafeTerminateProcess(HANDLE hProcess, UINT uExitCode)
{
  DWORD dwTID, dwCode, dwErr= 0;
  HANDLE hProcessDup= INVALID_HANDLE_VALUE;
  HANDLE hRT= NULL;
  HINSTANCE hKernel= GetModuleHandle("Kernel32");
  BOOL bSuccess= FALSE;

  BOOL bDup= DuplicateHandle(GetCurrentProcess(),
                             hProcess, GetCurrentProcess(), &hProcessDup,
                             PROCESS_ALL_ACCESS, FALSE, 0);

  // Detect the special case where the process is
  // already dead...
  if (GetExitCodeProcess((bDup) ? hProcessDup : hProcess, &dwCode) &&
      (dwCode == STILL_ACTIVE))
  {
    FARPROC pfnExitProc;

    pfnExitProc= GetProcAddress(hKernel, "ExitProcess");

    hRT= CreateRemoteThread((bDup) ? hProcessDup : hProcess, NULL, 0,
                            (LPTHREAD_START_ROUTINE)pfnExitProc,
                            (PVOID)uExitCode, 0, &dwTID);

    if (hRT == NULL)
      dwErr= GetLastError();
  }
  else
    dwErr= ERROR_PROCESS_ABORTED;

  if (hRT)
  {
    // Must wait process to terminate to
    // guarantee that it has exited...
    WaitForSingleObject((bDup) ? hProcessDup : hProcess, INFINITE);

    CloseHandle(hRT);
    bSuccess= TRUE;
  }

  if (bDup)
    CloseHandle(hProcessDup);

  if (!bSuccess)
    SetLastError(dwErr);

  return bSuccess;
}

int kill(pid_t pid, int signum)
{
  HANDLE processhandle= ::OpenProcess(PROCESS_ALL_ACCESS, FALSE, pid);
  if (signum == SIGTERM)
    ::SafeTerminateProcess(processhandle, 0);
  else
    ::TerminateProcess(processhandle, -1);
  return 0;
}
#endif

void Instance::kill_instance(int signum)
{
  pid_t pid;
  /* if there are no pid, everything seems to be fine */
  if ((pid= options.get_pid()) != 0)            /* get pid from pidfile */
  {
    /*
      If we cannot kill mysqld, then it has propably crashed.
      Let us try to remove staled pidfile and return successfully
      as mysqld is probably stopped.
    */
    if (!kill(pid, signum))
      options.unlink_pidfile();
    else if (signum == SIGKILL)      /* really killed instance with SIGKILL */
      log_error("The instance %s is being stopped forsibly. Normally \
                it should not happed. Probably the instance has been \
                hanging. You should also check your IM setup",
                options.instance_name);
  }
  return;
}

/*
  We execute this function to initialize instance parameters.
  Return value: 0 - ok. 1 - unable to init DYNAMIC_ARRAY.
*/

int Instance::init(const char *name_arg)
{
  return options.init(name_arg);
}


int Instance::complete_initialization(Instance_map *instance_map_arg,
                                      const char *mysqld_path,
                                      uint instance_type)
{
  instance_map= instance_map_arg;
  return options.complete_initialization(mysqld_path, instance_type);
}