mariadb/storage/myisam/mi_open.c

/* Copyright (C) 2000-2006 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; 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

/* open a isam-database */

#include "fulltext.h"
#include "sp_defs.h"
#include "rt_index.h"
#include <m_ctype.h>
#include <mysql_version.h>

#if defined(MSDOS) || defined(__WIN__)
#ifdef __WIN__
#include <fcntl.h>
#else
#include <process.h>			/* Prototype for getpid */
#endif
#endif
#ifdef VMS
#include "static.c"
#endif

static void setup_key_functions(MI_KEYDEF *keyinfo);
#define get_next_element(to,pos,size) { memcpy((char*) to,pos,(size_t) size); \
					pos+=size;}


#define disk_pos_assert(pos, end_pos) \
if (pos > end_pos)             \
{                              \
  my_errno=HA_ERR_CRASHED;     \
  goto err;                    \
}


/******************************************************************************
** Return the shared struct if the table is already open.
** In MySQL the server will handle version issues.
******************************************************************************/

MI_INFO *test_if_reopen(char *filename)
{
  LIST *pos;

  for (pos=myisam_open_list ; pos ; pos=pos->next)
  {
    MI_INFO *info=(MI_INFO*) pos->data;
    MYISAM_SHARE *share=info->s;
    DBUG_ASSERT(strcmp(share->unique_file_name,filename) ||
                share->last_version);
    if (!strcmp(share->unique_file_name,filename) && share->last_version)
      return info;
  }
  return 0;
}


/******************************************************************************
  open a MyISAM database.
  See my_base.h for the handle_locking argument
  if handle_locking and HA_OPEN_ABORT_IF_CRASHED then abort if the table
  is marked crashed or if we are not using locking and the table doesn't
  have an open count of 0.
******************************************************************************/

MI_INFO *mi_open(const char *name, int mode, uint open_flags)
{
  int lock_error,kfile,open_mode,save_errno,have_rtree=0, realpath_err;
  uint i,j,len,errpos,head_length,base_pos,offset,info_length,keys,
    key_parts,unique_key_parts,fulltext_keys,uniques;
  char name_buff[FN_REFLEN], org_name[FN_REFLEN], index_name[FN_REFLEN],
       data_name[FN_REFLEN];
  uchar *disk_cache, *disk_pos, *end_pos;
  MI_INFO info,*m_info,*old_info;
  MYISAM_SHARE share_buff,*share;
  ulong rec_per_key_part[HA_MAX_POSSIBLE_KEY*HA_MAX_KEY_SEG];
  my_off_t key_root[HA_MAX_POSSIBLE_KEY],key_del[MI_MAX_KEY_BLOCK_SIZE];
  ulonglong max_key_file_length, max_data_file_length;
  DBUG_ENTER("mi_open");

  LINT_INIT(m_info);
  kfile= -1;
  lock_error=1;
  errpos=0;
  head_length=sizeof(share_buff.state.header);
  bzero((uchar*) &info,sizeof(info));

  realpath_err= my_realpath(name_buff,
                            fn_format(org_name,name,"",MI_NAME_IEXT,4),MYF(0));
  if (my_is_symlink(org_name) &&
      (realpath_err || (*myisam_test_invalid_symlink)(name_buff)))
  {
    my_errno= HA_WRONG_CREATE_OPTION;
    DBUG_RETURN (NULL);
  }

  pthread_mutex_lock(&THR_LOCK_myisam);
  if (!(old_info=test_if_reopen(name_buff)))
  {
    share= &share_buff;
    bzero((uchar*) &share_buff,sizeof(share_buff));
    share_buff.state.rec_per_key_part=rec_per_key_part;
    share_buff.state.key_root=key_root;
    share_buff.state.key_del=key_del;
    share_buff.key_cache= multi_key_cache_search((uchar*) name_buff,
                                                 strlen(name_buff),
                                                 dflt_key_cache);

    DBUG_EXECUTE_IF("myisam_pretend_crashed_table_on_open",
                    if (strstr(name, "/crashed"))
                    {
                      my_errno= HA_ERR_CRASHED;
                      goto err;
                    });
    if ((kfile=my_open(name_buff,(open_mode=O_RDWR) | O_SHARE,MYF(0))) < 0)
    {
      if ((errno != EROFS && errno != EACCES) ||
	  mode != O_RDONLY ||
	  (kfile=my_open(name_buff,(open_mode=O_RDONLY) | O_SHARE,MYF(0))) < 0)
	goto err;
    }
    share->mode=open_mode;
    errpos=1;
    if (my_read(kfile, share->state.header.file_version, head_length,
		MYF(MY_NABP)))
    {
      my_errno= HA_ERR_NOT_A_TABLE;
      goto err;
    }
    if (bcmp(share->state.header.file_version, myisam_file_magic, 4))
    {
      DBUG_PRINT("error",("Wrong header in %s",name_buff));
      DBUG_DUMP("error_dump", share->state.header.file_version,
		(size_t) head_length);
      my_errno=HA_ERR_NOT_A_TABLE;
      goto err;
    }
    share->options= mi_uint2korr(share->state.header.options);
    if (share->options &
	~(HA_OPTION_PACK_RECORD | HA_OPTION_PACK_KEYS |
	  HA_OPTION_COMPRESS_RECORD | HA_OPTION_READ_ONLY_DATA |
	  HA_OPTION_TEMP_COMPRESS_RECORD | HA_OPTION_CHECKSUM |
          HA_OPTION_TMP_TABLE | HA_OPTION_DELAY_KEY_WRITE |
          HA_OPTION_RELIES_ON_SQL_LAYER | HA_OPTION_NULL_FIELDS))
    {
      DBUG_PRINT("error",("wrong options: 0x%lx", share->options));
      my_errno=HA_ERR_OLD_FILE;
      goto err;
    }
    if ((share->options & HA_OPTION_RELIES_ON_SQL_LAYER) &&
        ! (open_flags & HA_OPEN_FROM_SQL_LAYER))
    {
      DBUG_PRINT("error", ("table cannot be openned from non-sql layer"));
      my_errno= HA_ERR_UNSUPPORTED;
      goto err;
    }
    /* Don't call realpath() if the name can't be a link */
    if (!strcmp(name_buff, org_name) ||
        my_readlink(index_name, org_name, MYF(0)) == -1)
      (void) strmov(index_name, org_name);
    *strrchr(org_name, '.')= '\0';
    (void) fn_format(data_name,org_name,"",MI_NAME_DEXT,
                     MY_APPEND_EXT|MY_UNPACK_FILENAME|MY_RESOLVE_SYMLINKS);

    info_length=mi_uint2korr(share->state.header.header_length);
    base_pos=mi_uint2korr(share->state.header.base_pos);
    if (!(disk_cache= (uchar*) my_alloca(info_length+128)))
    {
      my_errno=ENOMEM;
      goto err;
    }
    end_pos=disk_cache+info_length;
    errpos=2;

    VOID(my_seek(kfile,0L,MY_SEEK_SET,MYF(0)));
    if (!(open_flags & HA_OPEN_TMP_TABLE))
    {
      if ((lock_error=my_lock(kfile,F_RDLCK,0L,F_TO_EOF,
			      MYF(open_flags & HA_OPEN_WAIT_IF_LOCKED ?
				  0 : MY_SHORT_WAIT))) &&
	  !(open_flags & HA_OPEN_IGNORE_IF_LOCKED))
	goto err;
    }
    errpos=3;
    if (my_read(kfile,disk_cache,info_length,MYF(MY_NABP)))
    {
      my_errno=HA_ERR_CRASHED;
      goto err;
    }
    len=mi_uint2korr(share->state.header.state_info_length);
    keys=    (uint) share->state.header.keys;
    uniques= (uint) share->state.header.uniques;
    fulltext_keys= (uint) share->state.header.fulltext_keys;
    key_parts= mi_uint2korr(share->state.header.key_parts);
    unique_key_parts= mi_uint2korr(share->state.header.unique_key_parts);
    if (len != MI_STATE_INFO_SIZE)
    {
      DBUG_PRINT("warning",
		 ("saved_state_info_length: %d  state_info_length: %d",
		  len,MI_STATE_INFO_SIZE));
    }
    share->state_diff_length=len-MI_STATE_INFO_SIZE;

    mi_state_info_read(disk_cache, &share->state);
    len= mi_uint2korr(share->state.header.base_info_length);
    if (len != MI_BASE_INFO_SIZE)
    {
      DBUG_PRINT("warning",("saved_base_info_length: %d  base_info_length: %d",
			    len,MI_BASE_INFO_SIZE));
    }
    disk_pos= mi_n_base_info_read(disk_cache + base_pos, &share->base);
    share->state.state_length=base_pos;

    if (!(open_flags & HA_OPEN_FOR_REPAIR) &&
	((share->state.changed & STATE_CRASHED) ||
	 ((open_flags & HA_OPEN_ABORT_IF_CRASHED) &&
	  (my_disable_locking && share->state.open_count))))
    {
      DBUG_PRINT("error",("Table is marked as crashed. open_flags: %u  "
                          "changed: %u  open_count: %u  !locking: %d",
                          open_flags, share->state.changed,
                          share->state.open_count, my_disable_locking));
      my_errno=((share->state.changed & STATE_CRASHED_ON_REPAIR) ?
		HA_ERR_CRASHED_ON_REPAIR : HA_ERR_CRASHED_ON_USAGE);
      goto err;
    }

    /* sanity check */
    if (share->base.keystart > 65535 || share->base.rec_reflength > 8)
    {
      my_errno=HA_ERR_CRASHED;
      goto err;
    }

    key_parts+=fulltext_keys*FT_SEGS;
    if (share->base.max_key_length > HA_MAX_KEY_BUFF || keys > MI_MAX_KEY ||
	key_parts > MI_MAX_KEY * HA_MAX_KEY_SEG)
    {
      DBUG_PRINT("error",("Wrong key info:  Max_key_length: %d  keys: %d  key_parts: %d", share->base.max_key_length, keys, key_parts));
      my_errno=HA_ERR_UNSUPPORTED;
      goto err;
    }

    /* Correct max_file_length based on length of sizeof(off_t) */
    max_data_file_length=
      (share->options & (HA_OPTION_PACK_RECORD | HA_OPTION_COMPRESS_RECORD)) ?
      (((ulonglong) 1 << (share->base.rec_reflength*8))-1) :
      (mi_safe_mul(share->base.pack_reclength,
		   (ulonglong) 1 << (share->base.rec_reflength*8))-1);
    max_key_file_length=
      mi_safe_mul(MI_MIN_KEY_BLOCK_LENGTH,
		  ((ulonglong) 1 << (share->base.key_reflength*8))-1);
#if SIZEOF_OFF_T == 4
    set_if_smaller(max_data_file_length, INT_MAX32);
    set_if_smaller(max_key_file_length, INT_MAX32);
#endif
#if USE_RAID && SYSTEM_SIZEOF_OFF_T == 4
    set_if_smaller(max_key_file_length, INT_MAX32);
    if (!share->base.raid_type)
    {
      set_if_smaller(max_data_file_length, INT_MAX32);
    }
    else
    {
      set_if_smaller(max_data_file_length,
		     (ulonglong) share->base.raid_chunks << 31);
    }
#elif !defined(USE_RAID)
    if (share->base.raid_type)
    {
      DBUG_PRINT("error",("Table uses RAID but we don't have RAID support"));
      my_errno=HA_ERR_UNSUPPORTED;
      goto err;
    }
#endif
    share->base.max_data_file_length=(my_off_t) max_data_file_length;
    share->base.max_key_file_length=(my_off_t) max_key_file_length;

    if (share->options & HA_OPTION_COMPRESS_RECORD)
      share->base.max_key_length+=2;	/* For safety */

    /* Add space for node pointer */
    share->base.max_key_length+= share->base.key_reflength;

    if (!my_multi_malloc(MY_WME,
			 &share,sizeof(*share),
			 &share->state.rec_per_key_part,sizeof(long)*key_parts,
			 &share->keyinfo,keys*sizeof(MI_KEYDEF),
			 &share->uniqueinfo,uniques*sizeof(MI_UNIQUEDEF),
			 &share->keyparts,
			 (key_parts+unique_key_parts+keys+uniques) *
			 sizeof(HA_KEYSEG),
			 &share->rec,
			 (share->base.fields+1)*sizeof(MI_COLUMNDEF),
			 &share->blobs,sizeof(MI_BLOB)*share->base.blobs,
			 &share->unique_file_name,strlen(name_buff)+1,
			 &share->index_file_name,strlen(index_name)+1,
			 &share->data_file_name,strlen(data_name)+1,
			 &share->state.key_root,keys*sizeof(my_off_t),
			 &share->state.key_del,
			 (share->state.header.max_block_size_index*sizeof(my_off_t)),
#ifdef THREAD
			 &share->key_root_lock,sizeof(rw_lock_t)*keys,
#endif
			 &share->mmap_lock,sizeof(rw_lock_t),
			 NullS))
      goto err;
    errpos=4;
    *share=share_buff;
    memcpy((char*) share->state.rec_per_key_part,
	   (char*) rec_per_key_part, sizeof(long)*key_parts);
    memcpy((char*) share->state.key_root,
	   (char*) key_root, sizeof(my_off_t)*keys);
    memcpy((char*) share->state.key_del,
	   (char*) key_del, (sizeof(my_off_t) *
			     share->state.header.max_block_size_index));
    strmov(share->unique_file_name, name_buff);
    share->unique_name_length= strlen(name_buff);
    strmov(share->index_file_name,  index_name);
    strmov(share->data_file_name,   data_name);

    share->blocksize=min(IO_SIZE,myisam_block_size);
    {
      HA_KEYSEG *pos=share->keyparts;
      uint32 ftkey_nr= 1;
      for (i=0 ; i < keys ; i++)
      {
        share->keyinfo[i].share= share;
	disk_pos=mi_keydef_read(disk_pos, &share->keyinfo[i]);
        disk_pos_assert(disk_pos + share->keyinfo[i].keysegs * HA_KEYSEG_SIZE,
 			end_pos);
        if (share->keyinfo[i].key_alg == HA_KEY_ALG_RTREE)
          have_rtree=1;
	set_if_smaller(share->blocksize,share->keyinfo[i].block_length);
	share->keyinfo[i].seg=pos;
	for (j=0 ; j < share->keyinfo[i].keysegs; j++,pos++)
	{
	  disk_pos=mi_keyseg_read(disk_pos, pos);
          if (pos->flag & HA_BLOB_PART &&
              ! (share->options & (HA_OPTION_COMPRESS_RECORD |
                                   HA_OPTION_PACK_RECORD)))
          {
            my_errno= HA_ERR_CRASHED;
            goto err;
          }
	  if (pos->type == HA_KEYTYPE_TEXT ||
              pos->type == HA_KEYTYPE_VARTEXT1 ||
              pos->type == HA_KEYTYPE_VARTEXT2)
	  {
	    if (!pos->language)
	      pos->charset=default_charset_info;
	    else if (!(pos->charset= get_charset(pos->language, MYF(MY_WME))))
	    {
	      my_errno=HA_ERR_UNKNOWN_CHARSET;
	      goto err;
	    }
	  }
	  else if (pos->type == HA_KEYTYPE_BINARY)
	    pos->charset= &my_charset_bin;
	}
	if (share->keyinfo[i].flag & HA_SPATIAL)
	{
#ifdef HAVE_SPATIAL
	  uint sp_segs=SPDIMS*2;
	  share->keyinfo[i].seg=pos-sp_segs;
	  share->keyinfo[i].keysegs--;
#else
	  my_errno=HA_ERR_UNSUPPORTED;
	  goto err;
#endif
	}
        else if (share->keyinfo[i].flag & HA_FULLTEXT)
	{
          if (!fulltext_keys)
          { /* 4.0 compatibility code, to be removed in 5.0 */
            share->keyinfo[i].seg=pos-FT_SEGS;
            share->keyinfo[i].keysegs-=FT_SEGS;
          }
          else
          {
            uint k;
            share->keyinfo[i].seg=pos;
            for (k=0; k < FT_SEGS; k++)
            {
              *pos= ft_keysegs[k];
              pos[0].language= pos[-1].language;
              if (!(pos[0].charset= pos[-1].charset))
              {
                my_errno=HA_ERR_CRASHED;
                goto err;
              }
              pos++;
            }
          }
          if (!share->ft2_keyinfo.seg)
          {
            memcpy(& share->ft2_keyinfo, & share->keyinfo[i], sizeof(MI_KEYDEF));
            share->ft2_keyinfo.keysegs=1;
            share->ft2_keyinfo.flag=0;
            share->ft2_keyinfo.keylength=
            share->ft2_keyinfo.minlength=
            share->ft2_keyinfo.maxlength=HA_FT_WLEN+share->base.rec_reflength;
            share->ft2_keyinfo.seg=pos-1;
            share->ft2_keyinfo.end=pos;
            setup_key_functions(& share->ft2_keyinfo);
          }
          share->keyinfo[i].ftkey_nr= ftkey_nr++;
	}
        setup_key_functions(share->keyinfo+i);
	share->keyinfo[i].end=pos;
	pos->type=HA_KEYTYPE_END;			/* End */
	pos->length=share->base.rec_reflength;
	pos->null_bit=0;
	pos->flag=0;					/* For purify */
	pos++;
      }
      
      for (i=0 ; i < uniques ; i++)
      {
	disk_pos=mi_uniquedef_read(disk_pos, &share->uniqueinfo[i]);
        disk_pos_assert(disk_pos + share->uniqueinfo[i].keysegs *
			HA_KEYSEG_SIZE, end_pos);
	share->uniqueinfo[i].seg=pos;
	for (j=0 ; j < share->uniqueinfo[i].keysegs; j++,pos++)
	{
	  disk_pos=mi_keyseg_read(disk_pos, pos);
	  if (pos->type == HA_KEYTYPE_TEXT ||
              pos->type == HA_KEYTYPE_VARTEXT1 ||
              pos->type == HA_KEYTYPE_VARTEXT2)
	  {
	    if (!pos->language)
	      pos->charset=default_charset_info;
	    else if (!(pos->charset= get_charset(pos->language, MYF(MY_WME))))
	    {
	      my_errno=HA_ERR_UNKNOWN_CHARSET;
	      goto err;
	    }
	  }
	}
	share->uniqueinfo[i].end=pos;
	pos->type=HA_KEYTYPE_END;			/* End */
	pos->null_bit=0;
	pos->flag=0;
	pos++;
      }
      share->ftkeys= ftkey_nr;
    }

    disk_pos_assert(disk_pos + share->base.fields *MI_COLUMNDEF_SIZE, end_pos);
    for (i=j=offset=0 ; i < share->base.fields ; i++)
    {
      disk_pos=mi_recinfo_read(disk_pos,&share->rec[i]);
      share->rec[i].pack_type=0;
      share->rec[i].huff_tree=0;
      share->rec[i].offset=offset;
      if (share->rec[i].type == FIELD_BLOB)
      {
	share->blobs[j].pack_length=
	  share->rec[i].length - portable_sizeof_char_ptr;
	share->blobs[j].offset=offset;
	j++;
      }
#if MYSQL_VERSION_ID <= 60100
      /* This is to detect old checksum option */
      if (share->rec[i].null_bit)
        share->has_null_fields= 1;
      if (share->rec[i].type == FIELD_VARCHAR)
        share->has_varchar_fields= 1;
#endif
      offset+=share->rec[i].length;
    }
    share->rec[i].type=(int) FIELD_LAST;	/* End marker */
    if (offset > share->base.reclength)
    {
      /* purecov: begin inspected */
      my_errno= HA_ERR_CRASHED;
      goto err;
      /* purecov: end */
    }

    if (! lock_error)
    {
      VOID(my_lock(kfile,F_UNLCK,0L,F_TO_EOF,MYF(MY_SEEK_NOT_DONE)));
      lock_error=1;			/* Database unlocked */
    }

    if (mi_open_datafile(&info, share, name, -1))
      goto err;
    errpos=5;

    share->kfile=kfile;
    share->this_process=(ulong) getpid();
    share->last_process= share->state.process;
    share->base.key_parts=key_parts;
    share->base.all_key_parts=key_parts+unique_key_parts;
    if (!(share->last_version=share->state.version))
      share->last_version=1;			/* Safety */
    share->rec_reflength=share->base.rec_reflength; /* May be changed */
    share->base.margin_key_file_length=(share->base.max_key_file_length -
					(keys ? MI_INDEX_BLOCK_MARGIN *
					 share->blocksize * keys : 0));
    share->blocksize=min(IO_SIZE,myisam_block_size);
    share->data_file_type=STATIC_RECORD;
    if (share->options & HA_OPTION_COMPRESS_RECORD)
    {
      share->data_file_type = COMPRESSED_RECORD;
      share->options|= HA_OPTION_READ_ONLY_DATA;
      info.s=share;
      if (_mi_read_pack_info(&info,
			     (pbool)
			     test(!(share->options &
				    (HA_OPTION_PACK_RECORD |
				     HA_OPTION_TEMP_COMPRESS_RECORD)))))
	goto err;
    }
    else if (share->options & HA_OPTION_PACK_RECORD)
      share->data_file_type = DYNAMIC_RECORD;
    my_afree(disk_cache);
    mi_setup_functions(share);
    share->is_log_table= FALSE;
#ifdef THREAD
    thr_lock_init(&share->lock);
    VOID(pthread_mutex_init(&share->intern_lock,MY_MUTEX_INIT_FAST));
    for (i=0; i<keys; i++)
      VOID(my_rwlock_init(&share->key_root_lock[i], NULL));
    VOID(my_rwlock_init(&share->mmap_lock, NULL));
    if (!thr_lock_inited)
    {
      /* Probably a single threaded program; Don't use concurrent inserts */
      myisam_concurrent_insert=0;
    }
    else if (myisam_concurrent_insert)
    {
      share->concurrent_insert=
	((share->options & (HA_OPTION_READ_ONLY_DATA | HA_OPTION_TMP_TABLE |
			   HA_OPTION_COMPRESS_RECORD |
			   HA_OPTION_TEMP_COMPRESS_RECORD)) ||
	 (open_flags & HA_OPEN_TMP_TABLE) ||
	 have_rtree) ? 0 : 1;
      if (share->concurrent_insert)
      {
	share->lock.get_status=mi_get_status;
	share->lock.copy_status=mi_copy_status;
	share->lock.update_status=mi_update_status;
        share->lock.restore_status= mi_restore_status;
	share->lock.check_status=mi_check_status;
        share->lock.fix_status= (void (*)(void *, void *)) mi_fix_status;
      }
    }
#endif
    /*
      Memory mapping can only be requested after initializing intern_lock.
    */
    if (open_flags & HA_OPEN_MMAP)
    {
      info.s= share;
      mi_extra(&info, HA_EXTRA_MMAP, 0);
    }
  }
  else
  {
    share= old_info->s;
    if (mode == O_RDWR && share->mode == O_RDONLY)
    {
      my_errno=EACCES;				/* Can't open in write mode */
      goto err;
    }
    if (mi_open_datafile(&info, share, name, old_info->dfile))
      goto err;
    errpos=5;
    have_rtree= old_info->rtree_recursion_state != NULL;
  }

  /* alloc and set up private structure parts */
  if (!my_multi_malloc(MY_WME,
		       &m_info,sizeof(MI_INFO),
		       &info.blobs,sizeof(MI_BLOB)*share->base.blobs,
		       &info.buff,(share->base.max_key_block_length*2+
				   share->base.max_key_length),
		       &info.lastkey,share->base.max_key_length*3+1,
		       &info.first_mbr_key, share->base.max_key_length,
		       &info.filename,strlen(name)+1,
		       &info.rtree_recursion_state,have_rtree ? 1024 : 0,
		       NullS))
    goto err;
  errpos=6;

  if (!have_rtree)
    info.rtree_recursion_state= NULL;

  strmov(info.filename,name);
  memcpy(info.blobs,share->blobs,sizeof(MI_BLOB)*share->base.blobs);
  info.lastkey2=info.lastkey+share->base.max_key_length;

  info.s=share;
  info.lastpos= HA_OFFSET_ERROR;
  info.update= (short) (HA_STATE_NEXT_FOUND+HA_STATE_PREV_FOUND);
  info.open_flag= open_flags;
  info.opt_flag=READ_CHECK_USED;
  info.this_unique= (ulong) info.dfile; /* Uniq number in process */
  if (share->data_file_type == COMPRESSED_RECORD)
    info.this_unique= share->state.unique;
  info.this_loop=0;				/* Update counter */
  info.last_unique= share->state.unique;
  info.last_loop=   share->state.update_count;
  if (mode == O_RDONLY)
    share->options|=HA_OPTION_READ_ONLY_DATA;
  info.lock_type=F_UNLCK;
  info.quick_mode=0;
  info.bulk_insert=0;
  info.ft1_to_ft2=0;
  info.errkey= -1;
  info.page_changed=1;
  pthread_mutex_lock(&share->intern_lock);
  info.read_record=share->read_record;
  share->reopen++;
  share->write_flag=MYF(MY_NABP | MY_WAIT_IF_FULL);
  if (share->options & HA_OPTION_READ_ONLY_DATA)
  {
    info.lock_type=F_RDLCK;
    share->r_locks++;
    share->tot_locks++;
  }
  if ((open_flags & HA_OPEN_TMP_TABLE) ||
      (share->options & HA_OPTION_TMP_TABLE))
  {
    share->temporary=share->delay_key_write=1;
    share->write_flag=MYF(MY_NABP);
    share->w_locks++;			/* We don't have to update status */
    share->tot_locks++;
    info.lock_type=F_WRLCK;
  }
  if (((open_flags & HA_OPEN_DELAY_KEY_WRITE) ||
      (share->options & HA_OPTION_DELAY_KEY_WRITE)) &&
      myisam_delay_key_write)
    share->delay_key_write=1;
  info.state= &share->state.state;	/* Change global values by default */
  pthread_mutex_unlock(&share->intern_lock);

  /* Allocate buffer for one record */

  /* prerequisites: bzero(info) && info->s=share; are met. */
  if (!mi_alloc_rec_buff(&info, -1, &info.rec_buff))
    goto err;
  bzero(info.rec_buff, mi_get_rec_buff_len(&info, info.rec_buff));

  *m_info=info;
#ifdef THREAD
  thr_lock_data_init(&share->lock,&m_info->lock,(void*) m_info);
#endif
  m_info->open_list.data=(void*) m_info;
  myisam_open_list=list_add(myisam_open_list,&m_info->open_list);

  pthread_mutex_unlock(&THR_LOCK_myisam);

  bzero(info.buff, share->base.max_key_block_length * 2);

  if (myisam_log_file >= 0)
  {
    intern_filename(name_buff,share->index_file_name);
    _myisam_log(MI_LOG_OPEN, m_info, (uchar*) name_buff, strlen(name_buff));
  }
  DBUG_RETURN(m_info);

err:
  save_errno=my_errno ? my_errno : HA_ERR_END_OF_FILE;
  if ((save_errno == HA_ERR_CRASHED) ||
      (save_errno == HA_ERR_CRASHED_ON_USAGE) ||
      (save_errno == HA_ERR_CRASHED_ON_REPAIR))
    mi_report_error(save_errno, name);
  switch (errpos) {
  case 6:
    my_free((uchar*) m_info,MYF(0));
    /* fall through */
  case 5:
    VOID(my_close(info.dfile,MYF(0)));
    if (old_info)
      break;					/* Don't remove open table */
    /* fall through */
  case 4:
    my_free((uchar*) share,MYF(0));
    /* fall through */
  case 3:
    if (! lock_error)
      VOID(my_lock(kfile, F_UNLCK, 0L, F_TO_EOF, MYF(MY_SEEK_NOT_DONE)));
    /* fall through */
  case 2:
    my_afree(disk_cache);
    /* fall through */
  case 1:
    VOID(my_close(kfile,MYF(0)));
    /* fall through */
  case 0:
  default:
    break;
  }
  pthread_mutex_unlock(&THR_LOCK_myisam);
  my_errno=save_errno;
  DBUG_RETURN (NULL);
} /* mi_open */


uchar *mi_alloc_rec_buff(MI_INFO *info, ulong length, uchar **buf)
{
  uint extra;
  uint32 UNINIT_VAR(old_length);
  LINT_INIT(old_length);

  if (! *buf || length > (old_length=mi_get_rec_buff_len(info, *buf)))
  {
    uchar *newptr = *buf;

    /* to simplify initial init of info->rec_buf in mi_open and mi_extra */
    if (length == (ulong) -1)
    {
      if (info->s->options & HA_OPTION_COMPRESS_RECORD)
        length= max(info->s->base.pack_reclength, info->s->max_pack_length);
      else
        length= info->s->base.pack_reclength;
      length= max(length, info->s->base.max_key_length);
      /* Avoid unnecessary realloc */
      if (newptr && length == old_length)
	return newptr;
    }

    extra= ((info->s->options & HA_OPTION_PACK_RECORD) ?
	    ALIGN_SIZE(MI_MAX_DYN_BLOCK_HEADER)+MI_SPLIT_LENGTH+
	    MI_REC_BUFF_OFFSET : 0);
    if (extra && newptr)
      newptr-= MI_REC_BUFF_OFFSET;
    if (!(newptr=(uchar*) my_realloc((uchar*)newptr, length+extra+8,
                                     MYF(MY_ALLOW_ZERO_PTR))))
      return newptr;
    *((uint32 *) newptr)= (uint32) length;
    *buf= newptr+(extra ?  MI_REC_BUFF_OFFSET : 0);
  }
  return *buf;
}


ulonglong mi_safe_mul(ulonglong a, ulonglong b)
{
  ulonglong max_val= ~ (ulonglong) 0;		/* my_off_t is unsigned */

  if (!a || max_val / a < b)
    return max_val;
  return a*b;
}

	/* Set up functions in structs */

void mi_setup_functions(register MYISAM_SHARE *share)
{
  if (share->options & HA_OPTION_COMPRESS_RECORD)
  {
    share->read_record=_mi_read_pack_record;
    share->read_rnd=_mi_read_rnd_pack_record;
    if ((share->options &
              (HA_OPTION_PACK_RECORD | HA_OPTION_NULL_FIELDS)))
      share->calc_checksum= mi_checksum;
    else
      share->calc_checksum= mi_static_checksum;
    share->calc_check_checksum= share->calc_checksum;
    if (!(share->options & HA_OPTION_TEMP_COMPRESS_RECORD))
      share->calc_checksum=0;				/* No checksum */
  }
  else if (share->options & HA_OPTION_PACK_RECORD)
  {
    share->read_record=_mi_read_dynamic_record;
    share->read_rnd=_mi_read_rnd_dynamic_record;
    share->delete_record=_mi_delete_dynamic_record;
    share->compare_record=_mi_cmp_dynamic_record;
    share->compare_unique=_mi_cmp_dynamic_unique;
    share->calc_checksum= mi_checksum;
    share->calc_check_checksum= share->calc_checksum;

    /* add bits used to pack data to pack_reclength for faster allocation */
    share->base.pack_reclength+= share->base.pack_bits;
    if (share->base.blobs)
    {
      share->update_record=_mi_update_blob_record;
      share->write_record=_mi_write_blob_record;
    }
    else
    {
      share->write_record=_mi_write_dynamic_record;
      share->update_record=_mi_update_dynamic_record;
    }
  }
  else
  {
    share->read_record=_mi_read_static_record;
    share->read_rnd=_mi_read_rnd_static_record;
    share->delete_record=_mi_delete_static_record;
    share->compare_record=_mi_cmp_static_record;
    share->update_record=_mi_update_static_record;
    share->write_record=_mi_write_static_record;
    share->compare_unique=_mi_cmp_static_unique;
    if (share->options & HA_OPTION_NULL_FIELDS)
      share->calc_checksum= mi_checksum;
    else
      share->calc_checksum= mi_static_checksum;
    share->calc_check_checksum= share->calc_checksum;
  }
  share->file_read= mi_nommap_pread;
  share->file_write= mi_nommap_pwrite;
  if (!(share->options & HA_OPTION_CHECKSUM))
    share->calc_checksum=0;
  return;
}


static void setup_key_functions(register MI_KEYDEF *keyinfo)
{
  if (keyinfo->key_alg == HA_KEY_ALG_RTREE)
  {
#ifdef HAVE_RTREE_KEYS
    keyinfo->ck_insert = rtree_insert;
    keyinfo->ck_delete = rtree_delete;
#else
    DBUG_ASSERT(0); /* mi_open should check it never happens */
#endif
  }
  else
  {
    keyinfo->ck_insert = _mi_ck_write;
    keyinfo->ck_delete = _mi_ck_delete;
  }
  if (keyinfo->flag & HA_BINARY_PACK_KEY)
  {						/* Simple prefix compression */
    keyinfo->bin_search=_mi_seq_search;
    keyinfo->get_key=_mi_get_binary_pack_key;
    keyinfo->pack_key=_mi_calc_bin_pack_key_length;
    keyinfo->store_key=_mi_store_bin_pack_key;
  }
  else if (keyinfo->flag & HA_VAR_LENGTH_KEY)
  {
    keyinfo->get_key= _mi_get_pack_key;
    if (keyinfo->seg[0].flag & HA_PACK_KEY)
    {						/* Prefix compression */
      /*
        _mi_prefix_search() compares end-space against ASCII blank (' ').
        It cannot be used for character sets, that do not encode the
        blank character like ASCII does. UCS2 is an example. All
        character sets with a fixed width > 1 or a mimimum width > 1
        cannot represent blank like ASCII does. In these cases we have
        to use _mi_seq_search() for the search.
      */
      if (!keyinfo->seg->charset || use_strnxfrm(keyinfo->seg->charset) ||
          (keyinfo->seg->flag & HA_NULL_PART) ||
          (keyinfo->seg->charset->mbminlen > 1))
        keyinfo->bin_search=_mi_seq_search;
      else
        keyinfo->bin_search=_mi_prefix_search;
      keyinfo->pack_key=_mi_calc_var_pack_key_length;
      keyinfo->store_key=_mi_store_var_pack_key;
    }
    else
    {
      keyinfo->bin_search=_mi_seq_search;
      keyinfo->pack_key=_mi_calc_var_key_length; /* Variable length key */
      keyinfo->store_key=_mi_store_static_key;
    }
  }
  else
  {
    keyinfo->bin_search=_mi_bin_search;
    keyinfo->get_key=_mi_get_static_key;
    keyinfo->pack_key=_mi_calc_static_key_length;
    keyinfo->store_key=_mi_store_static_key;
  }
  return;
}


/*
   Function to save and store the header in the index file (.MYI)
*/

uint mi_state_info_write(File file, MI_STATE_INFO *state, uint pWrite)
{
  uchar  buff[MI_STATE_INFO_SIZE + MI_STATE_EXTRA_SIZE];
  uchar *ptr=buff;
  uint	i, keys= (uint) state->header.keys,
	key_blocks=state->header.max_block_size_index;
  DBUG_ENTER("mi_state_info_write");

  memcpy_fixed(ptr,&state->header,sizeof(state->header));
  ptr+=sizeof(state->header);

  /* open_count must be first because of _mi_mark_file_changed ! */
  mi_int2store(ptr,state->open_count);		ptr +=2;
  *ptr++= (uchar)state->changed; *ptr++= state->sortkey;
  mi_rowstore(ptr,state->state.records);	ptr +=8;
  mi_rowstore(ptr,state->state.del);		ptr +=8;
  mi_rowstore(ptr,state->split);		ptr +=8;
  mi_sizestore(ptr,state->dellink);		ptr +=8;
  mi_sizestore(ptr,state->state.key_file_length);	ptr +=8;
  mi_sizestore(ptr,state->state.data_file_length);	ptr +=8;
  mi_sizestore(ptr,state->state.empty);		ptr +=8;
  mi_sizestore(ptr,state->state.key_empty);	ptr +=8;
  mi_int8store(ptr,state->auto_increment);	ptr +=8;
  mi_int8store(ptr,(ulonglong) state->state.checksum);ptr +=8;
  mi_int4store(ptr,state->process);		ptr +=4;
  mi_int4store(ptr,state->unique);		ptr +=4;
  mi_int4store(ptr,state->status);		ptr +=4;
  mi_int4store(ptr,state->update_count);	ptr +=4;

  ptr+=state->state_diff_length;

  for (i=0; i < keys; i++)
  {
    mi_sizestore(ptr,state->key_root[i]);	ptr +=8;
  }
  for (i=0; i < key_blocks; i++)
  {
    mi_sizestore(ptr,state->key_del[i]);	ptr +=8;
  }
  if (pWrite & 2)				/* From isamchk */
  {
    uint key_parts= mi_uint2korr(state->header.key_parts);
    mi_int4store(ptr,state->sec_index_changed); ptr +=4;
    mi_int4store(ptr,state->sec_index_used);	ptr +=4;
    mi_int4store(ptr,state->version);		ptr +=4;
    mi_int8store(ptr,state->key_map);		ptr +=8;
    mi_int8store(ptr,(ulonglong) state->create_time);	ptr +=8;
    mi_int8store(ptr,(ulonglong) state->recover_time);	ptr +=8;
    mi_int8store(ptr,(ulonglong) state->check_time);	ptr +=8;
    mi_sizestore(ptr,state->rec_per_key_rows);	ptr+=8;
    for (i=0 ; i < key_parts ; i++)
    {
      mi_int4store(ptr,state->rec_per_key_part[i]);  ptr+=4;
    }
  }

  if (pWrite & 1)
    DBUG_RETURN(my_pwrite(file, buff, (size_t) (ptr-buff), 0L,
			  MYF(MY_NABP | MY_THREADSAFE)) != 0);
  DBUG_RETURN(my_write(file, buff, (size_t) (ptr-buff),
		       MYF(MY_NABP)) != 0);
}


uchar *mi_state_info_read(uchar *ptr, MI_STATE_INFO *state)
{
  uint i,keys,key_parts,key_blocks;
  memcpy_fixed(&state->header,ptr, sizeof(state->header));
  ptr +=sizeof(state->header);
  keys=(uint) state->header.keys;
  key_parts=mi_uint2korr(state->header.key_parts);
  key_blocks=state->header.max_block_size_index;

  state->open_count = mi_uint2korr(ptr);	ptr +=2;
  state->changed= *ptr++;
  state->sortkey = (uint) *ptr++;
  state->state.records= mi_rowkorr(ptr);	ptr +=8;
  state->state.del = mi_rowkorr(ptr);		ptr +=8;
  state->split	= mi_rowkorr(ptr);		ptr +=8;
  state->dellink= mi_sizekorr(ptr);		ptr +=8;
  state->state.key_file_length = mi_sizekorr(ptr);	ptr +=8;
  state->state.data_file_length= mi_sizekorr(ptr);	ptr +=8;
  state->state.empty	= mi_sizekorr(ptr);	ptr +=8;
  state->state.key_empty= mi_sizekorr(ptr);	ptr +=8;
  state->auto_increment=mi_uint8korr(ptr);	ptr +=8;
  state->state.checksum=(ha_checksum) mi_uint8korr(ptr);	ptr +=8;
  state->process= mi_uint4korr(ptr);		ptr +=4;
  state->unique = mi_uint4korr(ptr);		ptr +=4;
  state->status = mi_uint4korr(ptr);		ptr +=4;
  state->update_count=mi_uint4korr(ptr);	ptr +=4;

  ptr+= state->state_diff_length;

  for (i=0; i < keys; i++)
  {
    state->key_root[i]= mi_sizekorr(ptr);	ptr +=8;
  }
  for (i=0; i < key_blocks; i++)
  {
    state->key_del[i] = mi_sizekorr(ptr);	ptr +=8;
  }
  state->sec_index_changed = mi_uint4korr(ptr); ptr +=4;
  state->sec_index_used =    mi_uint4korr(ptr); ptr +=4;
  state->version     = mi_uint4korr(ptr);	ptr +=4;
  state->key_map     = mi_uint8korr(ptr);	ptr +=8;
  state->create_time = (time_t) mi_sizekorr(ptr);	ptr +=8;
  state->recover_time =(time_t) mi_sizekorr(ptr);	ptr +=8;
  state->check_time =  (time_t) mi_sizekorr(ptr);	ptr +=8;
  state->rec_per_key_rows=mi_sizekorr(ptr);	ptr +=8;
  for (i=0 ; i < key_parts ; i++)
  {
    state->rec_per_key_part[i]= mi_uint4korr(ptr); ptr+=4;
  }
  return ptr;
}


uint mi_state_info_read_dsk(File file, MI_STATE_INFO *state, my_bool pRead)
{
  uchar	buff[MI_STATE_INFO_SIZE + MI_STATE_EXTRA_SIZE];

  if (!myisam_single_user)
  {
    if (pRead)
    {
      if (my_pread(file, buff, state->state_length,0L, MYF(MY_NABP)))
	return 1;
    }
    else if (my_read(file, buff, state->state_length,MYF(MY_NABP)))
      return 1;
    mi_state_info_read(buff, state);
  }
  return 0;
}


/****************************************************************************
**  store and read of MI_BASE_INFO
****************************************************************************/

uint mi_base_info_write(File file, MI_BASE_INFO *base)
{
  uchar buff[MI_BASE_INFO_SIZE], *ptr=buff;

  mi_sizestore(ptr,base->keystart);			ptr +=8;
  mi_sizestore(ptr,base->max_data_file_length);		ptr +=8;
  mi_sizestore(ptr,base->max_key_file_length);		ptr +=8;
  mi_rowstore(ptr,base->records);			ptr +=8;
  mi_rowstore(ptr,base->reloc);				ptr +=8;
  mi_int4store(ptr,base->mean_row_length);		ptr +=4;
  mi_int4store(ptr,base->reclength);			ptr +=4;
  mi_int4store(ptr,base->pack_reclength);		ptr +=4;
  mi_int4store(ptr,base->min_pack_length);		ptr +=4;
  mi_int4store(ptr,base->max_pack_length);		ptr +=4;
  mi_int4store(ptr,base->min_block_length);		ptr +=4;
  mi_int4store(ptr,base->fields);			ptr +=4;
  mi_int4store(ptr,base->pack_fields);			ptr +=4;
  *ptr++=base->rec_reflength;
  *ptr++=base->key_reflength;
  *ptr++=base->keys;
  *ptr++=base->auto_key;
  mi_int2store(ptr,base->pack_bits);			ptr +=2;
  mi_int2store(ptr,base->blobs);			ptr +=2;
  mi_int2store(ptr,base->max_key_block_length);		ptr +=2;
  mi_int2store(ptr,base->max_key_length);		ptr +=2;
  mi_int2store(ptr,base->extra_alloc_bytes);		ptr +=2;
  *ptr++= base->extra_alloc_procent;
  *ptr++= base->raid_type;
  mi_int2store(ptr,base->raid_chunks);			ptr +=2;
  mi_int4store(ptr,base->raid_chunksize);		ptr +=4;
  bzero(ptr,6);						ptr +=6; /* extra */
  return my_write(file, buff, (size_t) (ptr-buff), MYF(MY_NABP)) != 0;
}


uchar *mi_n_base_info_read(uchar *ptr, MI_BASE_INFO *base)
{
  base->keystart = mi_sizekorr(ptr);			ptr +=8;
  base->max_data_file_length = mi_sizekorr(ptr);	ptr +=8;
  base->max_key_file_length = mi_sizekorr(ptr);		ptr +=8;
  base->records =  (ha_rows) mi_sizekorr(ptr);		ptr +=8;
  base->reloc = (ha_rows) mi_sizekorr(ptr);		ptr +=8;
  base->mean_row_length = mi_uint4korr(ptr);		ptr +=4;
  base->reclength = mi_uint4korr(ptr);			ptr +=4;
  base->pack_reclength = mi_uint4korr(ptr);		ptr +=4;
  base->min_pack_length = mi_uint4korr(ptr);		ptr +=4;
  base->max_pack_length = mi_uint4korr(ptr);		ptr +=4;
  base->min_block_length = mi_uint4korr(ptr);		ptr +=4;
  base->fields = mi_uint4korr(ptr);			ptr +=4;
  base->pack_fields = mi_uint4korr(ptr);		ptr +=4;

  base->rec_reflength = *ptr++;
  base->key_reflength = *ptr++;
  base->keys=		*ptr++;
  base->auto_key=	*ptr++;
  base->pack_bits = mi_uint2korr(ptr);			ptr +=2;
  base->blobs = mi_uint2korr(ptr);			ptr +=2;
  base->max_key_block_length= mi_uint2korr(ptr);	ptr +=2;
  base->max_key_length = mi_uint2korr(ptr);		ptr +=2;
  base->extra_alloc_bytes = mi_uint2korr(ptr);		ptr +=2;
  base->extra_alloc_procent = *ptr++;
  base->raid_type= *ptr++;
  base->raid_chunks= mi_uint2korr(ptr);			ptr +=2;
  base->raid_chunksize= mi_uint4korr(ptr);		ptr +=4;
  /* TO BE REMOVED: Fix for old RAID files */
  if (base->raid_type == 0)
  {
    base->raid_chunks=0;
    base->raid_chunksize=0;
  }

  ptr+=6;
  return ptr;
}

/*--------------------------------------------------------------------------
  mi_keydef
---------------------------------------------------------------------------*/

uint mi_keydef_write(File file, MI_KEYDEF *keydef)
{
  uchar buff[MI_KEYDEF_SIZE];
  uchar *ptr=buff;

  *ptr++ = (uchar) keydef->keysegs;
  *ptr++ = keydef->key_alg;			/* Rtree or Btree */
  mi_int2store(ptr,keydef->flag);		ptr +=2;
  mi_int2store(ptr,keydef->block_length);	ptr +=2;
  mi_int2store(ptr,keydef->keylength);		ptr +=2;
  mi_int2store(ptr,keydef->minlength);		ptr +=2;
  mi_int2store(ptr,keydef->maxlength);		ptr +=2;
  return my_write(file, buff, (size_t) (ptr-buff), MYF(MY_NABP)) != 0;
}

uchar *mi_keydef_read(uchar *ptr, MI_KEYDEF *keydef)
{
   keydef->keysegs	= (uint) *ptr++;
   keydef->key_alg	= *ptr++;		/* Rtree or Btree */

   keydef->flag		= mi_uint2korr(ptr);	ptr +=2;
   keydef->block_length = mi_uint2korr(ptr);	ptr +=2;
   keydef->keylength	= mi_uint2korr(ptr);	ptr +=2;
   keydef->minlength	= mi_uint2korr(ptr);	ptr +=2;
   keydef->maxlength	= mi_uint2korr(ptr);	ptr +=2;
   keydef->block_size_index= keydef->block_length/MI_MIN_KEY_BLOCK_LENGTH-1;
   keydef->underflow_block_length=keydef->block_length/3;
   keydef->version	= 0;			/* Not saved */
   keydef->parser       = &ft_default_parser;
   keydef->ftkey_nr     = 0;
   return ptr;
}

/***************************************************************************
**  mi_keyseg
***************************************************************************/

int mi_keyseg_write(File file, const HA_KEYSEG *keyseg)
{
  uchar buff[HA_KEYSEG_SIZE];
  uchar *ptr=buff;
  ulong pos;

  *ptr++= keyseg->type;
  *ptr++= keyseg->language;
  *ptr++= keyseg->null_bit;
  *ptr++= keyseg->bit_start;
  *ptr++= keyseg->bit_end;
  *ptr++= keyseg->bit_length;
  mi_int2store(ptr,keyseg->flag);	ptr+=2;
  mi_int2store(ptr,keyseg->length);	ptr+=2;
  mi_int4store(ptr,keyseg->start);	ptr+=4;
  pos= keyseg->null_bit ? keyseg->null_pos : keyseg->bit_pos;
  mi_int4store(ptr, pos);
  ptr+=4;
  
  return my_write(file, buff, (size_t) (ptr-buff), MYF(MY_NABP)) != 0;
}


uchar *mi_keyseg_read(uchar *ptr, HA_KEYSEG *keyseg)
{
   keyseg->type		= *ptr++;
   keyseg->language	= *ptr++;
   keyseg->null_bit	= *ptr++;
   keyseg->bit_start	= *ptr++;
   keyseg->bit_end	= *ptr++;
   keyseg->bit_length   = *ptr++;
   keyseg->flag		= mi_uint2korr(ptr);  ptr +=2;
   keyseg->length	= mi_uint2korr(ptr);  ptr +=2;
   keyseg->start	= mi_uint4korr(ptr);  ptr +=4;
   keyseg->null_pos	= mi_uint4korr(ptr);  ptr +=4;
   keyseg->charset=0;				/* Will be filled in later */
   if (keyseg->null_bit)
     /* We adjust bit_pos if null_bit is last in the byte */
     keyseg->bit_pos= (uint16)(keyseg->null_pos + (keyseg->null_bit == (1 << 7)));
   else
   {
     keyseg->bit_pos= (uint16)keyseg->null_pos;
     keyseg->null_pos= 0;
   }
   return ptr;
}

/*--------------------------------------------------------------------------
  mi_uniquedef
---------------------------------------------------------------------------*/

uint mi_uniquedef_write(File file, MI_UNIQUEDEF *def)
{
  uchar buff[MI_UNIQUEDEF_SIZE];
  uchar *ptr=buff;

  mi_int2store(ptr,def->keysegs);		ptr+=2;
  *ptr++=  (uchar) def->key;
  *ptr++ = (uchar) def->null_are_equal;

  return my_write(file, buff, (size_t) (ptr-buff), MYF(MY_NABP)) != 0;
}

uchar *mi_uniquedef_read(uchar *ptr, MI_UNIQUEDEF *def)
{
   def->keysegs = mi_uint2korr(ptr);
   def->key	= ptr[2];
   def->null_are_equal=ptr[3];
   return ptr+4;				/* 1 extra byte */
}

/***************************************************************************
**  MI_COLUMNDEF
***************************************************************************/

uint mi_recinfo_write(File file, MI_COLUMNDEF *recinfo)
{
  uchar buff[MI_COLUMNDEF_SIZE];
  uchar *ptr=buff;

  mi_int2store(ptr,recinfo->type);	ptr +=2;
  mi_int2store(ptr,recinfo->length);	ptr +=2;
  *ptr++ = recinfo->null_bit;
  mi_int2store(ptr,recinfo->null_pos);	ptr+= 2;
  return my_write(file, buff, (size_t) (ptr-buff), MYF(MY_NABP)) != 0;
}

uchar *mi_recinfo_read(uchar *ptr, MI_COLUMNDEF *recinfo)
{
   recinfo->type=  mi_sint2korr(ptr);	ptr +=2;
   recinfo->length=mi_uint2korr(ptr);	ptr +=2;
   recinfo->null_bit= (uint8) *ptr++;
   recinfo->null_pos=mi_uint2korr(ptr); ptr +=2;
   return ptr;
}

/**************************************************************************
Open data file with or without RAID
We can't use dup() here as the data file descriptors need to have different
active seek-positions.

The argument file_to_dup is here for the future if there would on some OS
exist a dup()-like call that would give us two different file descriptors.
*************************************************************************/

int mi_open_datafile(MI_INFO *info, MYISAM_SHARE *share, const char *org_name,
                     File file_to_dup __attribute__((unused)))
{
  char *data_name= share->data_file_name;
  char real_data_name[FN_REFLEN];

  if (org_name)
  {
    fn_format(real_data_name,org_name,"",MI_NAME_DEXT,4);
    if (my_is_symlink(real_data_name))
    {
      if (my_realpath(real_data_name, real_data_name, MYF(0)) ||
          (*myisam_test_invalid_symlink)(real_data_name))
      {
        my_errno= HA_WRONG_CREATE_OPTION;
        return 1;
      }
      data_name= real_data_name;
    }
  }
#ifdef USE_RAID
  if (share->base.raid_type)
  {
    info->dfile=my_raid_open(data_name,
			     share->mode | O_SHARE,
			     share->base.raid_type,
			     share->base.raid_chunks,
			     share->base.raid_chunksize,
			     MYF(MY_WME | MY_RAID));
  }
  else
#endif
    info->dfile=my_open(data_name, share->mode | O_SHARE, MYF(MY_WME));
  return info->dfile >= 0 ? 0 : 1;
}


int mi_open_keyfile(MYISAM_SHARE *share)
{
  if ((share->kfile=my_open(share->unique_file_name, share->mode | O_SHARE,
                            MYF(MY_WME))) < 0)
    return 1;
  return 0;
}


/*
  Disable all indexes.

  SYNOPSIS
    mi_disable_indexes()
    info        A pointer to the MyISAM storage engine MI_INFO struct.

  DESCRIPTION
    Disable all indexes.

  RETURN
    0  ok
*/

int mi_disable_indexes(MI_INFO *info)
{
  MYISAM_SHARE *share= info->s;

  mi_clear_all_keys_active(share->state.key_map);
  return 0;
}


/*
  Enable all indexes

  SYNOPSIS
    mi_enable_indexes()
    info        A pointer to the MyISAM storage engine MI_INFO struct.

  DESCRIPTION
    Enable all indexes. The indexes might have been disabled
    by mi_disable_index() before.
    The function works only if both data and indexes are empty,
    otherwise a repair is required.
    To be sure, call handler::delete_all_rows() before.

  RETURN
    0  ok
    HA_ERR_CRASHED data or index is non-empty.
*/

int mi_enable_indexes(MI_INFO *info)
{
  int error= 0;
  MYISAM_SHARE *share= info->s;

  if (share->state.state.data_file_length ||
      (share->state.state.key_file_length != share->base.keystart))
  {
    mi_print_error(info->s, HA_ERR_CRASHED);
    error= HA_ERR_CRASHED;
  }
  else
    mi_set_all_keys_active(share->state.key_map, share->base.keys);
  return error;
}


/*
  Test if indexes are disabled.

  SYNOPSIS
    mi_indexes_are_disabled()
    info        A pointer to the MyISAM storage engine MI_INFO struct.

  DESCRIPTION
    Test if indexes are disabled.

  RETURN
    0  indexes are not disabled
    1  all indexes are disabled
    2  non-unique indexes are disabled
*/

int mi_indexes_are_disabled(MI_INFO *info)
{
  MYISAM_SHARE *share= info->s;

  /*
    No keys or all are enabled. keys is the number of keys. Left shifted
    gives us only one bit set. When decreased by one, gives us all all bits
    up to this one set and it gets unset.
  */
  if (!share->base.keys ||
      (mi_is_all_keys_active(share->state.key_map, share->base.keys)))
    return 0;

  /* All are disabled */
  if (mi_is_any_key_active(share->state.key_map))
    return 1;

  /*
    We have keys. Some enabled, some disabled.
    Don't check for any non-unique disabled but return directly 2
  */
  return 2;
}