mariadb/mysys/my_thr_init.c

/* Copyright (C) 2000 MySQL 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 */

/*
  Functions to handle initializating and allocationg of all mysys & debug
  thread variables.
*/

#include "mysys_priv.h"
#include <m_string.h>

#ifdef THREAD
#ifdef USE_TLS
pthread_key(struct st_my_thread_var*, THR_KEY_mysys);
#else
pthread_key(struct st_my_thread_var, THR_KEY_mysys);
#endif /* USE_TLS */
pthread_mutex_t THR_LOCK_malloc,THR_LOCK_open,
	        THR_LOCK_lock,THR_LOCK_isam,THR_LOCK_myisam,THR_LOCK_heap,
	        THR_LOCK_net, THR_LOCK_charset; 
#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
pthread_mutex_t LOCK_localtime_r;
#endif
#ifndef HAVE_GETHOSTBYNAME_R
pthread_mutex_t LOCK_gethostbyname_r;
#endif
#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
pthread_mutexattr_t my_fast_mutexattr;
#endif
#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
pthread_mutexattr_t my_errorcheck_mutexattr;
#endif

/*
  initialize thread environment

  SYNOPSIS
    my_thread_global_init()

  RETURN
    0  ok
    1  error (Couldn't create THR_KEY_mysys)
*/

my_bool my_thread_global_init(void)
{
  if (pthread_key_create(&THR_KEY_mysys,0))
  {
    fprintf(stderr,"Can't initialize threads: error %d\n",errno);
    return 1;
  }

#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
  /*
    Set mutex type to "fast" a.k.a "adaptive"

    In this case the thread may steal the mutex from some other thread
    that is waiting for the same mutex.  This will save us some
    context switches but may cause a thread to 'starve forever' while
    waiting for the mutex (not likely if the code within the mutex is
    short).
  */
  pthread_mutexattr_init(&my_fast_mutexattr);
  pthread_mutexattr_settype(&my_fast_mutexattr,
                            PTHREAD_MUTEX_ADAPTIVE_NP);
#endif
#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
  /*
    Set mutex type to "errorcheck" a.k.a "adaptive"
  */
  pthread_mutexattr_init(&my_errorcheck_mutexattr);
  pthread_mutexattr_settype(&my_errorcheck_mutexattr,
                            PTHREAD_MUTEX_ERRORCHECK);
#endif

  pthread_mutex_init(&THR_LOCK_malloc,MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&THR_LOCK_open,MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&THR_LOCK_lock,MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&THR_LOCK_isam,MY_MUTEX_INIT_SLOW);
  pthread_mutex_init(&THR_LOCK_myisam,MY_MUTEX_INIT_SLOW);
  pthread_mutex_init(&THR_LOCK_heap,MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&THR_LOCK_net,MY_MUTEX_INIT_FAST);
  pthread_mutex_init(&THR_LOCK_charset,MY_MUTEX_INIT_FAST);
#if defined( __WIN__) || defined(OS2)
  win_pthread_init();
#endif
#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
  pthread_mutex_init(&LOCK_localtime_r,MY_MUTEX_INIT_SLOW);
#endif
#ifndef HAVE_GETHOSTBYNAME_R
  pthread_mutex_init(&LOCK_gethostbyname_r,MY_MUTEX_INIT_SLOW);
#endif
  if (my_thread_init())
  {
    my_thread_global_end();			/* Clean up */
    return 1;
  }
  return 0;
}


void my_thread_global_end(void)
{
  pthread_key_delete(THR_KEY_mysys);
#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
  pthread_mutexattr_destroy(&my_fast_mutexattr);
#endif
#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
  pthread_mutexattr_destroy(&my_errorcheck_mutexattr);
#endif
  pthread_mutex_destroy(&THR_LOCK_malloc);
  pthread_mutex_destroy(&THR_LOCK_open);
  pthread_mutex_destroy(&THR_LOCK_lock);
  pthread_mutex_destroy(&THR_LOCK_isam);
  pthread_mutex_destroy(&THR_LOCK_myisam);
  pthread_mutex_destroy(&THR_LOCK_heap);
  pthread_mutex_destroy(&THR_LOCK_net);
  pthread_mutex_destroy(&THR_LOCK_charset);
#if !defined(HAVE_LOCALTIME_R) || !defined(HAVE_GMTIME_R)
  pthread_mutex_destroy(&LOCK_localtime_r);
#endif
#ifndef HAVE_GETHOSTBYNAME_R
  pthread_mutex_destroy(&LOCK_gethostbyname_r);
#endif
}

static long thread_id=0;

/*
  We can't use mutex_locks here if we are using windows as
  we may have compiled the program with SAFE_MUTEX, in which
  case the checking of mutex_locks will not work until
  the pthread_self thread specific variable is initialized.
*/

my_bool my_thread_init(void)
{
  struct st_my_thread_var *tmp;
  my_bool error=0;

#ifdef EXTRA_DEBUG_THREADS
  fprintf(stderr,"my_thread_init(): thread_id=%ld\n",pthread_self());
#endif  
#if !defined(__WIN__) || defined(USE_TLS) || ! defined(SAFE_MUTEX)
  pthread_mutex_lock(&THR_LOCK_lock);
#endif

#if !defined(__WIN__) || defined(USE_TLS)
  if (my_pthread_getspecific(struct st_my_thread_var *,THR_KEY_mysys))
  {
#ifdef EXTRA_DEBUG_THREADS
    fprintf(stderr,"my_thread_init() called more than once in thread %ld\n",
	        pthread_self());
#endif    
    goto end;
  }
  if (!(tmp= (struct st_my_thread_var *) calloc(1, sizeof(*tmp))))
  {
    error= 1;
    goto end;
  }
  pthread_setspecific(THR_KEY_mysys,tmp);

#else
  /*
    Skip initialization if the thread specific variable is already initialized
  */
  if (THR_KEY_mysys.id)
    goto end;
  tmp= &THR_KEY_mysys;
#endif
  tmp->id= ++thread_id;
#if defined(__WIN__) && defined(EMBEDDED_LIBRARY)
  tmp->thread_self= (pthread_t)getpid();
#endif
  pthread_mutex_init(&tmp->mutex,MY_MUTEX_INIT_FAST);
  pthread_cond_init(&tmp->suspend, NULL);
  tmp->init= 1;

end:
#if !defined(__WIN__) || defined(USE_TLS) || ! defined(SAFE_MUTEX)
  pthread_mutex_unlock(&THR_LOCK_lock);
#endif
  return error;
}


void my_thread_end(void)
{
  struct st_my_thread_var *tmp;
  tmp= my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);

#ifdef EXTRA_DEBUG_THREADS
  fprintf(stderr,"my_thread_end(): tmp=%p,thread_id=%ld\n",
	  tmp,pthread_self());
#endif  
  if (tmp && tmp->init)
  {
#if !defined(DBUG_OFF)
    /* tmp->dbug is allocated inside DBUG library */
    if (tmp->dbug)
    {
      free(tmp->dbug);
      tmp->dbug=0;
    }
#endif
#if !defined(__bsdi__) && !defined(__OpenBSD__) || defined(HAVE_mit_thread)
 /* bsdi and openbsd 3.5 dumps core here */
    pthread_cond_destroy(&tmp->suspend);
#endif
    pthread_mutex_destroy(&tmp->mutex);
#if (!defined(__WIN__) && !defined(OS2)) || defined(USE_TLS)
    free(tmp);
#else
    tmp->init= 0;
#endif
  }
  /* The following free has to be done, even if my_thread_var() is 0 */
#if (!defined(__WIN__) && !defined(OS2)) || defined(USE_TLS)
  pthread_setspecific(THR_KEY_mysys,0);
#endif
}

struct st_my_thread_var *_my_thread_var(void)
{
  struct st_my_thread_var *tmp=
    my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
#if defined(USE_TLS)
  /* This can only happen in a .DLL */
  if (!tmp)
  {
    my_thread_init();
    tmp=my_pthread_getspecific(struct st_my_thread_var*,THR_KEY_mysys);
  }
#endif
  return tmp;
}


/****************************************************************************
  Get name of current thread.
****************************************************************************/

#define UNKNOWN_THREAD -1

long my_thread_id()
{
#if defined(HAVE_PTHREAD_GETSEQUENCE_NP)
  return pthread_getsequence_np(pthread_self());
#elif (defined(__sun) || defined(__sgi) || defined(__linux__)) && !defined(HAVE_mit_thread)
  return pthread_self();
#else
  return my_thread_var->id;
#endif
}

#ifdef DBUG_OFF
const char *my_thread_name(void)
{
  return "no_name";
}

#else

const char *my_thread_name(void)
{
  char name_buff[100];
  struct st_my_thread_var *tmp=my_thread_var;
  if (!tmp->name[0])
  {
    long id=my_thread_id();
    sprintf(name_buff,"T@%ld", id);
    strmake(tmp->name,name_buff,THREAD_NAME_SIZE);
  }
  return tmp->name;
}
#endif /* DBUG_OFF */

#endif /* THREAD */