mariadb/server-tools/instance-manager/manager.cc

/* Copyright (C) 2003 MySQL AB & MySQL Finland AB & TCX DataKonsult AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include "manager.h"

#include <my_global.h>
#include <my_sys.h>
#include <m_string.h>
#include <signal.h>
#include <thr_alarm.h>

#include "thread_registry.h"
#include "listener.h"
#include "instance_map.h"
#include "options.h"
#include "user_map.h"
#include "log.h"
#include "guardian.h"

static int create_pid_file(const char *pid_file_name)
{
  if (FILE *pid_file= my_fopen(pid_file_name,
                               O_WRONLY | O_CREAT | O_BINARY, MYF(0)))
    {
      fprintf(pid_file, "%d\n", (int) getpid());
      my_fclose(pid_file, MYF(0));
    }
    else
    {
      log_error("can't create pid file %s: errno=%d, %s",
                pid_file_name, errno, strerror(errno));
      return 1;
    }
  return 0;
}


/*
  manager - entry point to the main instance manager process: start
  listener thread, write pid file and enter into signal handling.
  See also comments in mysqlmanager.cc to picture general Instance Manager
  architecture.
*/

void manager(const Options &options)
{
  Thread_registry thread_registry;
  /*
    All objects created in the manager() function live as long as
    thread_registry lives, and thread_registry is alive until there are
    working threads.
  */

  User_map user_map;
  Instance_map instance_map(options.default_mysqld_path,
                            options.default_admin_user,
                            options.default_admin_password);
  Guardian_thread guardian_thread(thread_registry,
                                  &instance_map,
                                  options.monitoring_interval);

  Listener_thread_args listener_args(thread_registry, options, user_map,
                                     instance_map);

  instance_map.guardian= &guardian_thread;

  if (instance_map.init() || user_map.init() || instance_map.load() ||
      user_map.load(options.password_file_name))
    return;

  /* write pid file */
  if (create_pid_file(options.pid_file_name))
    return;

  /* block signals */
  sigset_t mask;
  sigemptyset(&mask);
  sigaddset(&mask, SIGINT);
  sigaddset(&mask, SIGTERM);
  sigaddset(&mask, SIGPIPE);
  sigaddset(&mask, SIGHUP);
  /*
    We want this signal to be blocked in all theads but the signal
    one. It is needed for the thr_alarm subsystem to work.
  */
  sigaddset(&mask,THR_SERVER_ALARM);

  /* all new threads will inherite this signal mask */
  pthread_sigmask(SIG_BLOCK, &mask, NULL);

  /* create the listener */
  {
    pthread_t listener_thd_id;
    pthread_attr_t listener_thd_attr;
    int rc;

    pthread_attr_init(&listener_thd_attr);
    pthread_attr_setdetachstate(&listener_thd_attr, PTHREAD_CREATE_DETACHED);
    rc= pthread_create(&listener_thd_id, &listener_thd_attr, listener,
                       &listener_args);
    pthread_attr_destroy(&listener_thd_attr);
    if (rc)
    {
      log_error("manager(): pthread_create(listener) failed");
      goto err;
    }

  }

  /* create guardian thread */
  {
    pthread_t guardian_thd_id;
    pthread_attr_t guardian_thd_attr;
    int rc;

    pthread_attr_init(&guardian_thd_attr);
    pthread_attr_setdetachstate(&guardian_thd_attr, PTHREAD_CREATE_DETACHED);
    rc= pthread_create(&guardian_thd_id, &guardian_thd_attr, guardian,
                       &guardian_thread);
    pthread_attr_destroy(&guardian_thd_attr);
    if (rc)
    {
      log_error("manager(): pthread_create(guardian) failed");
      goto err;
    }

  }

  /*
    To work nicely with LinuxThreads, the signal thread is the first thread
    in the process.
  */
  int signo;
  bool shutdown_complete;

  shutdown_complete= FALSE;
  /*
     In our case the signal thread also implements functions of alarm thread.
     Here we init alarm thread functionality. We suppose that we won't have
     more then 10 alarms at the same time.
  */
  init_thr_alarm(10);
  /*
    Now we can init the list of guarded instances. We have to do it after
    alarm structures initialization as we have to use net_* functions while
    making the list. And they in their turn need alarms for timeout suppport.
  */
  guardian_thread.start();

  signal(SIGPIPE, SIG_IGN);

  while (!shutdown_complete)
  {
    sigwait(&mask, &signo);
    switch (signo)
    {
      case THR_SERVER_ALARM:
        process_alarm(signo);
      break;
      default:
        thread_registry.deliver_shutdown();
        shutdown_complete= TRUE;
      break;
    }
  }

err:
  /* delete the pid file */
  my_delete(options.pid_file_name, MYF(0));

  /* close permanent connections to the running instances */
  instance_map.cleanup();

  /* free alarm structures */
  end_thr_alarm(1);
  /* don't pthread_exit to kill all threads who did not shut down in time */
}