mariadb/mysys/my_os2tls.c

/* Copyright (C) Yuri Dario & 2000 MySQL AB
   All the above parties has a full, independent copyright to
   the following code, including the right to use the code in
   any manner without any demands from the other parties.

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

   This library 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
   Library General Public License for more details.

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

DWORD	 TlsAlloc( void);
BOOL	 TlsFree( DWORD);
PVOID	 TlsGetValue( DWORD);
BOOL	 TlsSetValue( DWORD, PVOID);

#define TLS_MINIMUM_AVAILABLE	64


PULONG		 tls_storage;	/* TLS local storage */
DWORD		 tls_bits[2];	/* TLS in-use bits   */
pthread_mutex_t  tls_mutex;	/* TLS mutex for in-use bits */


DWORD	 TlsAlloc( void)
{
  DWORD index = -1;
  DWORD mask, tibidx;
  int	 i;

  if (tls_storage == NULL)
  {

    APIRET rc;

    /* allocate memory for TLS storage */
    rc = DosAllocThreadLocalMemory( 1, &tls_storage);
    if (rc)
      fprintf( stderr, "DosAllocThreadLocalMemory error: return code = %u\n",
	       rc);
    /* create a mutex */
    if (pthread_mutex_init( &tls_mutex, NULL))
      fprintf( stderr, "Failed to init TLS mutex\n");
  }

  pthread_mutex_lock( &tls_mutex);

  tibidx = 0;
  if (tls_bits[0] == 0xFFFFFFFF)
  {
    if (tls_bits[1] == 0xFFFFFFFF)
    {
      fprintf( stderr, "tid#%d, no more TLS bits available\n", _threadid);
      pthread_mutex_unlock( &tls_mutex);
      return -1;
    }
    tibidx = 1;
  }

  for (i=0; i<32; i++)
  {
    mask = (1 << i);
    if ((tls_bits[ tibidx] & mask) == 0)
    {
      tls_bits[ tibidx] |= mask;
      index = (tibidx*32) + i;
      break;
    }
  }
  tls_storage[index] = 0;

  pthread_mutex_unlock( &tls_mutex);
  /* fprintf( stderr, "tid#%d, TlsAlloc index %d\n", _threadid, index); */
  return index;
}

BOOL TlsFree( DWORD index)
{
  int	  tlsidx;
  DWORD  mask;

  if (index >= TLS_MINIMUM_AVAILABLE)
    return NULL;

  pthread_mutex_lock( &tls_mutex);

  tlsidx = 0;
  if (index > 32)
    tlsidx++;

  mask = (1 << index);
  if (tls_bits[ tlsidx] & mask)
  {
    tls_bits[tlsidx] &= ~mask;
    tls_storage[index] = 0;
    pthread_mutex_unlock( &tls_mutex);
    return TRUE;
  }

  pthread_mutex_unlock( &tls_mutex);
  return FALSE;
}


PVOID TlsGetValue( DWORD index)
{
  if (index >= TLS_MINIMUM_AVAILABLE)
    return NULL;

  /* verify if memory has been allocated for this thread */
  if (*tls_storage == NULL)
  {
    /* allocate memory for indexes */
    *tls_storage = (ULONG)calloc( TLS_MINIMUM_AVAILABLE, sizeof(int));
    /* fprintf(stderr, "tid#%d, tls_storage %x\n", _threadid, *tls_storage); */
  }

  ULONG* tls_array = (ULONG*) *tls_storage;
  return (PVOID) tls_array[index];
}


BOOL TlsSetValue( DWORD index, PVOID val)
{

  /* verify if memory has been allocated for this thread */
  if (*tls_storage == NULL)
  {
    /* allocate memory for indexes */
    *tls_storage = (ULONG)calloc( TLS_MINIMUM_AVAILABLE, sizeof(int));
    /* fprintf(stderr, "tid#%d, tls_storage %x\n", _threadid, *tls_storage); */
  }

  if (index >= TLS_MINIMUM_AVAILABLE)
    return FALSE;

  ULONG* tls_array = (ULONG*) *tls_storage;
  /* fprintf( stderr, "tid#%d, TlsSetValue array %08x index %d -> %08x (old)\n", _threadid, tls_array, index, tls_array[ index]); */
  tls_array[ index] = (ULONG) val;
  /* fprintf( stderr, "tid#%d, TlsSetValue array %08x index %d -> %08x\n", _threadid, tls_array, index, val); */
  return TRUE;
}