mariadb/plugin/daemon_example/daemon_example.cc

/* Copyright (c) 2006, 2015, Oracle and/or its affiliates. All rights
   reserved.

   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; version 2 of the License.

   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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1335  USA */

#include <my_global.h>
#include <sql_priv.h>
#include <stdlib.h>
#include <ctype.h>
#include <mysql_version.h>
#include <mysql/plugin.h>
#include <my_dir.h>
#include "my_pthread.h"                         // pthread_handler_t
#include "my_sys.h"                             // my_write, my_malloc
#include "m_string.h"                           // strlen
#include "sql_plugin.h"                         // st_plugin_int

/*
  Disable __attribute__() on non-gcc compilers.
*/
#if !defined(__attribute__) && !defined(__GNUC__)
#define __attribute__(A)
#endif


#define HEART_STRING_BUFFER 100
  
struct mysql_heartbeat_context
{
  pthread_t heartbeat_thread;
  File heartbeat_file;
};

pthread_handler_t mysql_heartbeat(void *p)
{
  DBUG_ENTER("mysql_heartbeat");
  struct mysql_heartbeat_context *con= (struct mysql_heartbeat_context *)p;
  char buffer[HEART_STRING_BUFFER];
  time_t result;
  struct tm tm_tmp;

  while(1)
  {
    sleep(5);

    result= time(NULL);
    localtime_r(&result, &tm_tmp);
    my_snprintf(buffer, sizeof(buffer),
                "Heartbeat at %02d%02d%02d %2d:%02d:%02d\n",
                tm_tmp.tm_year % 100,
                tm_tmp.tm_mon+1,
                tm_tmp.tm_mday,
                tm_tmp.tm_hour,
                tm_tmp.tm_min,
                tm_tmp.tm_sec);
    my_write(con->heartbeat_file, (uchar*) buffer, strlen(buffer), MYF(0));
  }

  DBUG_RETURN(0);
}

/*
  Initialize the daemon example at server start or plugin installation.

  SYNOPSIS
    daemon_example_plugin_init()

  DESCRIPTION
    Starts up heartbeatbeat thread

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)
*/

static int daemon_example_plugin_init(void *p __attribute__ ((unused)))
{

  DBUG_ENTER("daemon_example_plugin_init");
  struct mysql_heartbeat_context *con;
  pthread_attr_t attr;          /* Thread attributes */
  char heartbeat_filename[FN_REFLEN];
  char buffer[HEART_STRING_BUFFER];
  time_t result= time(NULL);
  struct tm tm_tmp;

  struct st_plugin_int *plugin= (struct st_plugin_int *)p;

  con= (struct mysql_heartbeat_context *)
    my_malloc(PSI_NOT_INSTRUMENTED, sizeof(struct mysql_heartbeat_context), MYF(0));

  fn_format(heartbeat_filename, "mysql-heartbeat", "", ".log",
            MY_REPLACE_EXT | MY_UNPACK_FILENAME);
  unlink(heartbeat_filename);
  con->heartbeat_file= my_open(heartbeat_filename, O_CREAT|O_RDWR, MYF(0));

  /*
    No threads exist at this point in time, so this is thread safe.
  */
  localtime_r(&result, &tm_tmp);
  my_snprintf(buffer, sizeof(buffer),
              "Starting up at %02d%02d%02d %2d:%02d:%02d\n",
              tm_tmp.tm_year % 100,
              tm_tmp.tm_mon+1,
              tm_tmp.tm_mday,
              tm_tmp.tm_hour,
              tm_tmp.tm_min,
              tm_tmp.tm_sec);
  my_write(con->heartbeat_file, (uchar*) buffer, strlen(buffer), MYF(0));

  pthread_attr_init(&attr);
  pthread_attr_setdetachstate(&attr,
                              PTHREAD_CREATE_JOINABLE);


  /* now create the thread */
  if (pthread_create(&con->heartbeat_thread, &attr, mysql_heartbeat,
                     (void *)con) != 0)
  {
    fprintf(stderr,"Could not create heartbeat thread!\n");
    DBUG_RETURN(1);
  }
  plugin->data= (void *)con;

  DBUG_RETURN(0);
}


/*
  Terminate the daemon example at server shutdown or plugin deinstallation.

  SYNOPSIS
    daemon_example_plugin_deinit()
    Does nothing.

  RETURN VALUE
    0                    success
    1                    failure (cannot happen)

*/

static int daemon_example_plugin_deinit(void *p __attribute__ ((unused)))
{
  DBUG_ENTER("daemon_example_plugin_deinit");
  char buffer[HEART_STRING_BUFFER];
  struct st_plugin_int *plugin= (struct st_plugin_int *)p;
  struct mysql_heartbeat_context *con=
    (struct mysql_heartbeat_context *)plugin->data;
  time_t result= time(NULL);
  struct tm tm_tmp;

  pthread_cancel(con->heartbeat_thread);
  pthread_join(con->heartbeat_thread, NULL);

  localtime_r(&result, &tm_tmp);
  my_snprintf(buffer, sizeof(buffer),
              "Shutting down at %02d%02d%02d %2d:%02d:%02d\n",
              tm_tmp.tm_year % 100,
              tm_tmp.tm_mon+1,
              tm_tmp.tm_mday,
              tm_tmp.tm_hour,
              tm_tmp.tm_min,
              tm_tmp.tm_sec);
  my_write(con->heartbeat_file, (uchar*) buffer, strlen(buffer), MYF(0));

  /*
    Need to wait for the hearbeat thread to terminate before closing
    the file it writes to and freeing the memory it uses.
  */
  pthread_join(con->heartbeat_thread, NULL);

  my_close(con->heartbeat_file, MYF(0));

  my_free(con);

  DBUG_RETURN(0);
}


struct st_mysql_daemon daemon_example_plugin=
{ MYSQL_DAEMON_INTERFACE_VERSION  };

/*
  Plugin library descriptor
*/

maria_declare_plugin(daemon_example)
{
  MYSQL_DAEMON_PLUGIN,
  &daemon_example_plugin,
  "daemon_example",
  "Brian Aker",
  "Daemon example, creates a heartbeat beat file in mysql-heartbeat.log",
  PLUGIN_LICENSE_GPL,
  daemon_example_plugin_init, /* Plugin Init */
  daemon_example_plugin_deinit, /* Plugin Deinit */
  0x0100 /* 1.0 */,
  NULL,                       /* status variables                */
  NULL,                       /* system variables                */
  "1.0",                      /* string version */
  MariaDB_PLUGIN_MATURITY_EXPERIMENTAL /* maturity */
}
maria_declare_plugin_end;