storage/myisammrg/myrg_open.c

/* Copyright (c) 2000, 2021, Oracle and/or its affiliates.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License, version 2.0,
   as published by the Free Software Foundation.

   This program is also distributed with certain software (including
   but not limited to OpenSSL) that is licensed under separate terms,
   as designated in a particular file or component or in included license
   documentation.  The authors of MySQL hereby grant you an additional
   permission to link the program and your derivative works with the
   separately licensed software that they have included with MySQL.

   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, version 2.0, 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 Street, Fifth Floor, Boston, MA 02110-1301, USA */

/* open a MyISAM MERGE table */

#include "myrg_def.h"
#include <stddef.h>
#include <errno.h>

/*
	open a MyISAM MERGE table
	if handle_locking is 0 then exit with error if some table is locked
	if handle_locking is 1 then wait if table is locked

        NOTE: This function is not used in the MySQL server. It is for
        MERGE use independent from MySQL. Currently there is some code
        duplication between myrg_open() and myrg_parent_open() +
        myrg_attach_children(). Please duplicate changes in these
        functions or make common sub-functions.
*/

MYRG_INFO *myrg_open(const char *name, int mode, int handle_locking)
{
  int save_errno,errpos=0;
  uint files= 0, i, dir_length, length, key_parts= 0, min_keys= 0;
  ulonglong file_offset=0;
  char name_buff[FN_REFLEN*2],buff[FN_REFLEN],*end;
  MYRG_INFO *m_info=0;
  File fd;
  IO_CACHE file;
  MI_INFO *isam=0;
  uint found_merge_insert_method= 0;
  size_t name_buff_length;
  my_bool bad_children= FALSE;
  DBUG_ENTER("myrg_open");

  memset(&file, 0, sizeof(file));
  if ((fd= mysql_file_open(rg_key_file_MRG,
                           fn_format(name_buff, name, "", MYRG_NAME_EXT,
                                     MY_UNPACK_FILENAME|MY_APPEND_EXT),
                           O_RDONLY | O_SHARE, MYF(0))) < 0)
    goto err;
  errpos=1;
  if (init_io_cache(&file, fd, 4*IO_SIZE, READ_CACHE, 0, 0,
		    MYF(MY_WME | MY_NABP)))
    goto err;
  errpos=2;
  dir_length=dirname_part(name_buff, name, &name_buff_length);
  while ((length=my_b_gets(&file,buff,FN_REFLEN-1)))
  {
    if ((end=buff+length)[-1] == '\n')
      end[-1]='\0';
    if (buff[0] && buff[0] != '#')
      files++;
  }

  my_b_seek(&file, 0);
  while ((length=my_b_gets(&file,buff,FN_REFLEN-1)))
  {
    if ((end=buff+length)[-1] == '\n')
      *--end='\0';
    if (!buff[0])
      continue;		/* Skip empty lines */
    if (buff[0] == '#')
    {
      if (!strncmp(buff+1,"INSERT_METHOD=",14))
      {			/* Lookup insert method */
	int tmp= find_type(buff + 15, &merge_insert_method, FIND_TYPE_BASIC);
	found_merge_insert_method = (uint) (tmp >= 0 ? tmp : 0);
      }
      continue;		/* Skip comments */
    }

    if (!has_path(buff))
    {
      (void) strmake(name_buff+dir_length,buff,
                   sizeof(name_buff)-1-dir_length);
      (void) cleanup_dirname(buff,name_buff);
    }
    else
      fn_format(buff, buff, "", "", 0);
    if (!(isam=mi_open(buff,mode,(handle_locking?HA_OPEN_WAIT_IF_LOCKED:0))))
    {
      if (handle_locking & HA_OPEN_FOR_REPAIR)
      {
        myrg_print_wrong_table(buff);
        bad_children= TRUE;
        continue;
      }
      goto bad_children;
    }
    if (!m_info)                                /* First file */
    {
      key_parts=isam->s->base.key_parts;
      if (!(m_info= (MYRG_INFO*) my_malloc(rg_key_memory_MYRG_INFO,
                                           sizeof(MYRG_INFO) +
                                           files*sizeof(MYRG_TABLE) +
                                           key_parts*sizeof(long),
                                           MYF(MY_WME|MY_ZEROFILL))))
        goto err;
      assert(files);
      m_info->open_tables=(MYRG_TABLE *) (m_info+1);
      m_info->rec_per_key_part=(ulong *) (m_info->open_tables+files);
      m_info->tables= files;
      files= 0;
      m_info->reclength=isam->s->base.reclength;
      min_keys= isam->s->base.keys;
      errpos=3;
    }
    m_info->open_tables[files].table= isam;
    m_info->open_tables[files].file_offset=(my_off_t) file_offset;
    file_offset+=isam->state->data_file_length;
    files++;
    if (m_info->reclength != isam->s->base.reclength)
    {
      if (handle_locking & HA_OPEN_FOR_REPAIR)
      {
        myrg_print_wrong_table(buff);
        bad_children= TRUE;
        continue;
      }
      goto bad_children;
    }
    m_info->options|= isam->s->options;
    m_info->records+= isam->state->records;
    m_info->del+= isam->state->del;
    m_info->data_file_length+= isam->state->data_file_length;
    if (min_keys > isam->s->base.keys)
      min_keys= isam->s->base.keys;
    for (i=0; i < key_parts; i++)
      m_info->rec_per_key_part[i]+= (isam->s->state.rec_per_key_part[i] /
                                     m_info->tables);
  }

  if (bad_children)
    goto bad_children;
  if (!m_info && !(m_info= (MYRG_INFO*) my_malloc(rg_key_memory_MYRG_INFO,
                                                  sizeof(MYRG_INFO),
                                                  MYF(MY_WME | MY_ZEROFILL))))
    goto err;
  /* Don't mark table readonly, for ALTER TABLE ... UNION=(...) to work */
  m_info->options&= ~(HA_OPTION_COMPRESS_RECORD | HA_OPTION_READ_ONLY_DATA);
  m_info->merge_insert_method= found_merge_insert_method;

  if (sizeof(my_off_t) == 4 && file_offset > (ulonglong) (ulong) ~0L)
  {
    set_my_errno(HA_ERR_RECORD_FILE_FULL);
    goto err;
  }
  m_info->keys= min_keys;
  memset(&m_info->by_key, 0, sizeof(m_info->by_key));

  /* this works ok if the table list is empty */
  m_info->end_table=m_info->open_tables+files;
  m_info->last_used_table=m_info->open_tables;
  m_info->children_attached= TRUE;

  (void) mysql_file_close(fd, MYF(0));
  end_io_cache(&file);
  mysql_mutex_init(rg_key_mutex_MYRG_INFO_mutex,
                   &m_info->mutex, MY_MUTEX_INIT_FAST);
  m_info->open_list.data=(void*) m_info;
  mysql_mutex_lock(&THR_LOCK_open);
  myrg_open_list=list_add(myrg_open_list,&m_info->open_list);
  mysql_mutex_unlock(&THR_LOCK_open);
  DBUG_RETURN(m_info);

bad_children:
  set_my_errno(HA_ERR_WRONG_MRG_TABLE_DEF);
err:
  save_errno=my_errno();
  switch (errpos) {
  case 3:
    while (files)
      (void) mi_close(m_info->open_tables[--files].table);
    my_free(m_info);
    /* Fall through */
  case 2:
    end_io_cache(&file);
    /* Fall through */
  case 1:
    (void) mysql_file_close(fd, MYF(0));
  }
  set_my_errno(save_errno);
  DBUG_RETURN (NULL);
}


/**
  @brief Open parent table of a MyISAM MERGE table.

  @detail Open MERGE meta file to get the table name paths for the child
    tables. Count the children. Allocate and initialize MYRG_INFO
    structure. Call a callback function for each child table.

  @param[in]    parent_name     merge table name path as "database/table"
  @param[in]    callback        function to call for each child table
  @param[in]    callback_param  data pointer to give to the callback

  @return MYRG_INFO pointer
    @retval     != NULL         OK
    @retval     NULL            Error

  @note: Currently there is some code duplication between myrg_open()
    and myrg_parent_open() + myrg_attach_children(). Please duplicate
    changes in these functions or make common sub-functions.
*/

MYRG_INFO *myrg_parent_open(const char *parent_name,
                            int (*callback)(void*, const char*),
                            void *callback_param)
{
  MYRG_INFO *m_info= NULL;
  int       rc;
  int       errpos;
  int       save_errno;
  int       insert_method;
  uint      length;
  uint      child_count;
  File      fd;
  IO_CACHE  file_cache;
  char      parent_name_buff[FN_REFLEN * 2];
  char      child_name_buff[FN_REFLEN];
  DBUG_ENTER("myrg_parent_open");

  rc= 1;
  errpos= 0;
  memset(&file_cache, 0, sizeof(file_cache));

  /* Open MERGE meta file. */
  if ((fd= mysql_file_open(rg_key_file_MRG,
                           fn_format(parent_name_buff, parent_name,
                                     "", MYRG_NAME_EXT,
                                     MY_UNPACK_FILENAME|MY_APPEND_EXT),
                           O_RDONLY | O_SHARE, MYF(0))) < 0)
    goto err; /* purecov: inspected */
  errpos= 1;

  if (init_io_cache(&file_cache, fd, 4 * IO_SIZE, READ_CACHE, 0, 0,
                    MYF(MY_WME | MY_NABP)))
    goto err; /* purecov: inspected */
  errpos= 2;

  /* Count children. Determine insert method. */
  child_count= 0;
  insert_method= 0;
  while ((length= my_b_gets(&file_cache, child_name_buff, FN_REFLEN - 1)))
  {
    /* Remove line terminator. */
    if (child_name_buff[length - 1] == '\n')
      child_name_buff[--length]= '\0';

    /* Skip empty lines. */
    if (!child_name_buff[0])
      continue; /* purecov: inspected */

    /* Skip comments, but evaluate insert method. */
    if (child_name_buff[0] == '#')
    {
      if (!strncmp(child_name_buff + 1, "INSERT_METHOD=", 14))
      {
        /* Compare buffer with global methods list: merge_insert_method. */
        insert_method= find_type(child_name_buff + 15,
                                 &merge_insert_method, FIND_TYPE_BASIC);
      }
      continue;
    }

    /* Count the child. */
    child_count++;
  }

  /* Allocate MERGE parent table structure. */
  if (!(m_info= (MYRG_INFO*) my_malloc(rg_key_memory_MYRG_INFO,
                                       sizeof(MYRG_INFO) +
                                       child_count * sizeof(MYRG_TABLE),
                                       MYF(MY_WME | MY_ZEROFILL))))
    goto err; /* purecov: inspected */
  errpos= 3;
  m_info->open_tables= (MYRG_TABLE*) (m_info + 1);
  m_info->tables= child_count;
  m_info->merge_insert_method= insert_method > 0 ? insert_method : 0;
  /* This works even if the table list is empty. */
  m_info->end_table= m_info->open_tables + child_count;
  if (!child_count)
  {
    /* Do not attach/detach an empty child list. */
    m_info->children_attached= TRUE;
  }

  /* Call callback for each child. */
  my_b_seek(&file_cache, 0);
  while ((length= my_b_gets(&file_cache, child_name_buff, FN_REFLEN - 1)))
  {
    /* Remove line terminator. */
    if (child_name_buff[length - 1] == '\n')
      child_name_buff[--length]= '\0';

    /* Skip empty lines and comments. */
    if (!child_name_buff[0] || (child_name_buff[0] == '#'))
      continue;

    DBUG_PRINT("info", ("child: '%s'", child_name_buff));

    /* Callback registers child with handler table. */
    if ((rc= (*callback)(callback_param, child_name_buff)))
      goto err; /* purecov: inspected */
  }

  end_io_cache(&file_cache);
  (void) mysql_file_close(fd, MYF(0));
  mysql_mutex_init(rg_key_mutex_MYRG_INFO_mutex,
                   &m_info->mutex, MY_MUTEX_INIT_FAST);

  m_info->open_list.data= (void*) m_info;
  mysql_mutex_lock(&THR_LOCK_open);
  myrg_open_list= list_add(myrg_open_list, &m_info->open_list);
  mysql_mutex_unlock(&THR_LOCK_open);

  DBUG_RETURN(m_info);

  /* purecov: begin inspected */
 err:
  save_errno= my_errno();
  switch (errpos) {
  case 3:
    my_free(m_info);
    /* Fall through */
  case 2:
    end_io_cache(&file_cache);
    /* Fall through */
  case 1:
    (void) mysql_file_close(fd, MYF(0));
  }
  set_my_errno(save_errno);
  DBUG_RETURN (NULL);
  /* purecov: end */
}


/**
  @brief Attach children to a MyISAM MERGE parent table.

  @detail Call a callback function for each child table.
    The callback returns the MyISAM table handle of the child table.
    Check table definition match.

  @param[in]    m_info            MERGE parent table structure
  @param[in]    handle_locking    if contains HA_OPEN_FOR_REPAIR, warn about
                                  incompatible child tables, but continue
  @param[in]    callback          function to call for each child table
  @param[in]    callback_param    data pointer to give to the callback
  @param[in]    need_compat_check pointer to ha_myisammrg::need_compat_check
                                  (we need this one to decide if previously
                                  allocated buffers can be reused).

  @return status
    @retval     0               OK
    @retval     != 0            Error

  @note: Currently there is some code duplication between myrg_open()
    and myrg_parent_open() + myrg_attach_children(). Please duplicate
    changes in these functions or make common sub-functions.
*/

int myrg_attach_children(MYRG_INFO *m_info, int handle_locking,
                         MI_INFO *(*callback)(void*),
                         void *callback_param, my_bool *need_compat_check)
{
  ulonglong  file_offset;
  MI_INFO    *myisam;
  int        errpos;
  int        save_errno;
  uint       idx;
  uint       child_nr;
  uint       key_parts= 0;
  uint       min_keys;
  my_bool    bad_children= FALSE;
  my_bool    first_child= TRUE;
  DBUG_ENTER("myrg_attach_children");
  DBUG_PRINT("myrg", ("handle_locking: %d", handle_locking));

  /*
    This function can be called while another thread is trying to abort
    locks of this MERGE table. If the processor reorders instructions or
    write to memory, 'children_attached' could be set before
    'open_tables' has all the pointers to the children. Use of a mutex
    here and in ha_myisammrg::store_lock() forces consistent data.
  */
  mysql_mutex_lock(&m_info->mutex);
  errpos= 0;
  file_offset= 0;
  min_keys= 0;
  for (child_nr= 0; child_nr < m_info->tables; child_nr++)
  {
    if (! (myisam= (*callback)(callback_param)))
    {
      if (handle_locking & HA_OPEN_FOR_REPAIR)
      {
        /* An appropriate error should've been already pushed by callback. */
        bad_children= TRUE;
        continue;
      }
      goto bad_children;
    }

    DBUG_PRINT("myrg", ("child_nr: %u  table: '%s'",
                        child_nr, myisam->filename));

    /* Special handling when the first child is attached. */
    if (first_child)
    {
      first_child= FALSE;
      m_info->reclength= myisam->s->base.reclength;
      min_keys=  myisam->s->base.keys;
      key_parts= myisam->s->base.key_parts;
      if (*need_compat_check && m_info->rec_per_key_part)
      {
        my_free(m_info->rec_per_key_part);
        m_info->rec_per_key_part= NULL;
      }
      if (!m_info->rec_per_key_part)
      {
        if(!(m_info->rec_per_key_part= (ulong*)
             my_malloc(rg_key_memory_MYRG_INFO,
                       key_parts * sizeof(long), MYF(MY_WME))))
          goto err; /* purecov: inspected */
        errpos= 1;
      }
      memset(m_info->rec_per_key_part, 0, key_parts * sizeof(long));
    }

    /* Add MyISAM table info. */
    m_info->open_tables[child_nr].table= myisam;
    m_info->open_tables[child_nr].file_offset= (my_off_t) file_offset;
    file_offset+= myisam->state->data_file_length;

    /* Check table definition match. */
    if (m_info->reclength != myisam->s->base.reclength)
    {
      DBUG_PRINT("error", ("definition mismatch table: '%s'  repair: %d",
                           myisam->filename,
                           (handle_locking & HA_OPEN_FOR_REPAIR)));
      if (handle_locking & HA_OPEN_FOR_REPAIR)
      {
        myrg_print_wrong_table(myisam->filename);
        bad_children= TRUE;
        continue;
      }
      goto bad_children;
    }

    m_info->options|= myisam->s->options;
    m_info->records+= myisam->state->records;
    m_info->del+= myisam->state->del;
    m_info->data_file_length+= myisam->state->data_file_length;
    if (min_keys > myisam->s->base.keys)
      min_keys= myisam->s->base.keys; /* purecov: inspected */
    for (idx= 0; idx < key_parts; idx++)
      m_info->rec_per_key_part[idx]+= (myisam->s->state.rec_per_key_part[idx] /
                                       m_info->tables);
  }

  if (bad_children)
    goto bad_children;

  if (sizeof(my_off_t) == 4 && file_offset > (ulonglong) (ulong) ~0L)
  {
    set_my_errno(HA_ERR_RECORD_FILE_FULL);
    goto err;
  }
  /* Don't mark table readonly, for ALTER TABLE ... UNION=(...) to work */
  m_info->options&= ~(HA_OPTION_COMPRESS_RECORD | HA_OPTION_READ_ONLY_DATA);
  m_info->keys= min_keys;
  m_info->last_used_table= m_info->open_tables;
  m_info->children_attached= TRUE;
  mysql_mutex_unlock(&m_info->mutex);
  DBUG_RETURN(0);

bad_children:
  set_my_errno(HA_ERR_WRONG_MRG_TABLE_DEF);
err:
  save_errno= my_errno();
  switch (errpos) {
  case 1:
    my_free(m_info->rec_per_key_part);
    m_info->rec_per_key_part= NULL;
  }
  mysql_mutex_unlock(&m_info->mutex);
  set_my_errno(save_errno);
  DBUG_RETURN(1);
}


/**
  @brief Detach children from a MyISAM MERGE parent table.

  @param[in]    m_info          MERGE parent table structure

  @note Detach must not touch the children in any way.
    They may have been closed at ths point already.
    All references to the children should be removed.

  @return status
    @retval     0               OK
*/

int myrg_detach_children(MYRG_INFO *m_info)
{
  DBUG_ENTER("myrg_detach_children");
  /* For symmetry with myrg_attach_children() we use the mutex here. */
  mysql_mutex_lock(&m_info->mutex);
  if (m_info->tables)
  {
    /* Do not attach/detach an empty child list. */
    m_info->children_attached= FALSE;
    memset(m_info->open_tables, 0, m_info->tables * sizeof(MYRG_TABLE));
  }
  m_info->records= 0;
  m_info->del= 0;
  m_info->data_file_length= 0;
  m_info->options= 0;
  mysql_mutex_unlock(&m_info->mutex);
  DBUG_RETURN(0);
}