sp.cc

/* Copyright (C) 2002 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 */


#include "mysql_priv.h"
#include "sp.h"
#include "sp_head.h"
#include "sp_cache.h"
#include "sql_trigger.h"

static bool
create_string(THD *thd, String *buf,
	      int sp_type,
	      sp_name *name,
	      const char *params, ulong paramslen,
	      const char *returns, ulong returnslen,
	      const char *body, ulong bodylen,
	      st_sp_chistics *chistics);

/*
 *
 * DB storage of Stored PROCEDUREs and FUNCTIONs
 *
 */

enum
{
  MYSQL_PROC_FIELD_DB = 0,
  MYSQL_PROC_FIELD_NAME,
  MYSQL_PROC_FIELD_TYPE,
  MYSQL_PROC_FIELD_SPECIFIC_NAME,
  MYSQL_PROC_FIELD_LANGUAGE,
  MYSQL_PROC_FIELD_ACCESS,
  MYSQL_PROC_FIELD_DETERMINISTIC,
  MYSQL_PROC_FIELD_SECURITY_TYPE,
  MYSQL_PROC_FIELD_PARAM_LIST,
  MYSQL_PROC_FIELD_RETURNS,
  MYSQL_PROC_FIELD_BODY,
  MYSQL_PROC_FIELD_DEFINER,
  MYSQL_PROC_FIELD_CREATED,
  MYSQL_PROC_FIELD_MODIFIED,
  MYSQL_PROC_FIELD_SQL_MODE,
  MYSQL_PROC_FIELD_COMMENT,
  MYSQL_PROC_FIELD_COUNT
};

bool mysql_proc_table_exists= 1;

/* Tells what SP_DEFAULT_ACCESS should be mapped to */
#define SP_DEFAULT_ACCESS_MAPPING SP_CONTAINS_SQL


/*
  Close mysql.proc, opened with open_proc_table_for_read().

  SYNOPSIS
    close_proc_table()
      thd  Thread context
*/

static void close_proc_table(THD *thd)
{
  close_thread_tables(thd);
  thd->pop_open_tables_state();
}


/*
  Open the mysql.proc table for read.

  SYNOPSIS
    open_proc_table_for_read()
      thd  Thread context

  NOTES
    Thanks to restrictions which we put on opening and locking of
    this table for writing, we can open and lock it for reading
    even when we already have some other tables open and locked.
    One must call close_proc_table() to close table opened with
    this call.

  RETURN
    0	Error
    #	Pointer to TABLE object of mysql.proc
*/

static TABLE *open_proc_table_for_read(THD *thd)
{
  TABLE_LIST tables;
  TABLE *table;
  bool old_open_tables= thd->open_tables != 0;
  bool refresh;
  DBUG_ENTER("open_proc_table");

  /*
    Speed up things if mysql.proc doesn't exists. mysql_proc_table_exists
    is set when we create or read stored procedure or on flush privileges.
  */
  if (!mysql_proc_table_exists)
    DBUG_RETURN(0);

  if (thd->push_open_tables_state())
    DBUG_RETURN(0);

  bzero((char*) &tables, sizeof(tables));
  tables.db= (char*) "mysql";
  tables.table_name= tables.alias= (char*)"proc";
  if (!(table= open_table(thd, &tables, thd->mem_root, &refresh,
                          MYSQL_LOCK_IGNORE_FLUSH)))
  {
    thd->pop_open_tables_state();
    mysql_proc_table_exists= 0;
    DBUG_RETURN(0);
  }

  DBUG_ASSERT(table->s->system_table);

  table->reginfo.lock_type= TL_READ;
  /*
    If we have other tables opened, we have to ensure we are not blocked
    by a flush tables or global read lock, as this could lead to a deadlock
  */
  if (!(thd->lock= mysql_lock_tables(thd, &table, 1,
                                     old_open_tables ?
                                     (MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK |
                                      MYSQL_LOCK_IGNORE_FLUSH) : 0)))
  {
    close_proc_table(thd);
    DBUG_RETURN(0);
  }
  DBUG_RETURN(table);
}


/*
  Open the mysql.proc table for update.

  SYNOPSIS
    open_proc_table_for_update()
      thd  Thread context

  NOTES
    Table opened with this call should closed using close_thread_tables().

  RETURN
    0	Error
    #	Pointer to TABLE object of mysql.proc
*/

static TABLE *open_proc_table_for_update(THD *thd)
{
  TABLE_LIST tables;
  TABLE *table;
  DBUG_ENTER("open_proc_table");

  bzero((char*) &tables, sizeof(tables));
  tables.db= (char*) "mysql";
  tables.table_name= tables.alias= (char*)"proc";
  tables.lock_type= TL_WRITE;

  table= open_ltable(thd, &tables, TL_WRITE);

  /*
    Under explicit LOCK TABLES or in prelocked mode we should not
    say that mysql.proc table does not exist if we are unable to
    open and lock it for writing since this condition may be
    transient.
  */
  if (!(thd->locked_tables || thd->prelocked_mode) || table)
    mysql_proc_table_exists= test(table);

  DBUG_RETURN(table);
}


/*
  Find row in open mysql.proc table representing stored routine.

  SYNOPSIS
    db_find_routine_aux()
      thd    Thread context
      type   Type of routine to find (function or procedure)
      name   Name of routine
      table  TABLE object for open mysql.proc table.

  RETURN VALUE
    SP_OK           - Routine found
    SP_KEY_NOT_FOUND- No routine with given name
*/

static int
db_find_routine_aux(THD *thd, int type, sp_name *name, TABLE *table)
{
  byte key[MAX_KEY_LENGTH];	// db, name, optional key length type
  DBUG_ENTER("db_find_routine_aux");
  DBUG_PRINT("enter", ("type: %d name: %*s",
		       type, name->m_name.length, name->m_name.str));

  /*
    Create key to find row. We have to use field->store() to be able to
    handle VARCHAR and CHAR fields.
    Assumption here is that the three first fields in the table are
    'db', 'name' and 'type' and the first key is the primary key over the
    same fields.
  */
  if (name->m_name.length > table->field[1]->field_length)
    DBUG_RETURN(SP_KEY_NOT_FOUND);
  table->field[0]->store(name->m_db.str, name->m_db.length, &my_charset_bin);
  table->field[1]->store(name->m_name.str, name->m_name.length,
                         &my_charset_bin);
  table->field[2]->store((longlong) type);
  key_copy(key, table->record[0], table->key_info,
           table->key_info->key_length);

  if (table->file->index_read_idx(table->record[0], 0,
				  key, table->key_info->key_length,
				  HA_READ_KEY_EXACT))
    DBUG_RETURN(SP_KEY_NOT_FOUND);

  DBUG_RETURN(SP_OK);
}


/*
  Find routine definition in mysql.proc table and create corresponding
  sp_head object for it.

  SYNOPSIS
    db_find_routine()
      thd   Thread context
      type  Type of routine (TYPE_ENUM_PROCEDURE/...)
      name  Name of routine
      sphp  Out parameter in which pointer to created sp_head
            object is returned (0 in case of error).

  NOTE
    This function may damage current LEX during execution, so it is good
    idea to create temporary LEX and make it active before calling it.

  RETURN VALUE
    0     - Success
    non-0 - Error (may be one of special codes like SP_KEY_NOT_FOUND)
*/

static int
db_find_routine(THD *thd, int type, sp_name *name, sp_head **sphp)
{
  extern int yyparse(void *thd);
  TABLE *table;
  const char *params, *returns, *body;
  int ret;
  const char *definer;
  longlong created;
  longlong modified;
  st_sp_chistics chistics;
  char *ptr;
  uint length;
  char buff[65];
  String str(buff, sizeof(buff), &my_charset_bin);
  ulong sql_mode;
  DBUG_ENTER("db_find_routine");
  DBUG_PRINT("enter", ("type: %d name: %*s",
		       type, name->m_name.length, name->m_name.str));

  *sphp= 0;                                     // In case of errors
  if (!(table= open_proc_table_for_read(thd)))
    DBUG_RETURN(SP_OPEN_TABLE_FAILED);

  if ((ret= db_find_routine_aux(thd, type, name, table)) != SP_OK)
    goto done;

  if (table->s->fields != MYSQL_PROC_FIELD_COUNT)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }

  bzero((char *)&chistics, sizeof(chistics));
  if ((ptr= get_field(thd->mem_root,
		      table->field[MYSQL_PROC_FIELD_ACCESS])) == NULL)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }
  switch (ptr[0]) {
  case 'N':
    chistics.daccess= SP_NO_SQL;
    break;
  case 'C':
    chistics.daccess= SP_CONTAINS_SQL;
    break;
  case 'R':
    chistics.daccess= SP_READS_SQL_DATA;
    break;
  case 'M':
    chistics.daccess= SP_MODIFIES_SQL_DATA;
    break;
  default:
    chistics.daccess= SP_DEFAULT_ACCESS_MAPPING;
  }

  if ((ptr= get_field(thd->mem_root,
		      table->field[MYSQL_PROC_FIELD_DETERMINISTIC])) == NULL)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }
  chistics.detistic= (ptr[0] == 'N' ? FALSE : TRUE);    

  if ((ptr= get_field(thd->mem_root,
		      table->field[MYSQL_PROC_FIELD_SECURITY_TYPE])) == NULL)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }
  chistics.suid= (ptr[0] == 'I' ? SP_IS_NOT_SUID : SP_IS_SUID);

  if ((params= get_field(thd->mem_root,
			 table->field[MYSQL_PROC_FIELD_PARAM_LIST])) == NULL)
  {
    params= "";
  }

  if (type == TYPE_ENUM_PROCEDURE)
    returns= "";
  else if ((returns= get_field(thd->mem_root,
			       table->field[MYSQL_PROC_FIELD_RETURNS])) == NULL)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }

  if ((body= get_field(thd->mem_root,
		       table->field[MYSQL_PROC_FIELD_BODY])) == NULL)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }

  // Get additional information
  if ((definer= get_field(thd->mem_root,
			  table->field[MYSQL_PROC_FIELD_DEFINER])) == NULL)
  {
    ret= SP_GET_FIELD_FAILED;
    goto done;
  }

  modified= table->field[MYSQL_PROC_FIELD_MODIFIED]->val_int();
  created= table->field[MYSQL_PROC_FIELD_CREATED]->val_int();

  sql_mode= (ulong) table->field[MYSQL_PROC_FIELD_SQL_MODE]->val_int();

  table->field[MYSQL_PROC_FIELD_COMMENT]->val_str(&str, &str);

  ptr= 0;
  if ((length= str.length()))
    ptr= thd->strmake(str.ptr(), length);
  chistics.comment.str= ptr;
  chistics.comment.length= length;

  close_proc_table(thd);
  table= 0;

  {
    String defstr;
    LEX *oldlex= thd->lex;
    char olddb[128];
    bool dbchanged;
    enum enum_sql_command oldcmd= thd->lex->sql_command;
    ulong old_sql_mode= thd->variables.sql_mode;
    ha_rows select_limit= thd->variables.select_limit;

    thd->variables.sql_mode= sql_mode;
    thd->variables.select_limit= HA_POS_ERROR;

    defstr.set_charset(system_charset_info);
    if (!create_string(thd, &defstr,
		       type,
		       name,
		       params, strlen(params),
		       returns, strlen(returns),
		       body, strlen(body),
		       &chistics))
    {
      ret= SP_INTERNAL_ERROR;
      goto done;
    }

    dbchanged= FALSE;
    if ((ret= sp_use_new_db(thd, name->m_db.str, olddb, sizeof(olddb),
			    1, &dbchanged)))
      goto done;

    {
      /* This is something of a kludge. We need to initialize some fields
       * in thd->lex (the unit and master stuff), and the easiest way to
       * do it is, is to call mysql_init_query(), but this unfortunately
       * resets teh value_list where we keep the CALL parameters. So we
       * copy the list and then restore it. (... and found_semicolon too).
       */
      List<Item> tmpvals= thd->lex->value_list;
      char *tmpfsc= thd->lex->found_semicolon;

      lex_start(thd, (uchar*)defstr.c_ptr(), defstr.length());
      thd->lex->value_list= tmpvals;
      thd->lex->found_semicolon= tmpfsc;
    }

    if (yyparse(thd) || thd->is_fatal_error || thd->lex->sphead == NULL)
    {
      LEX *newlex= thd->lex;
      sp_head *sp= newlex->sphead;

      if (dbchanged && (ret= sp_change_db(thd, olddb, 1)))
	goto done;
      if (sp)
      {
	delete sp;
	newlex->sphead= NULL;
      }
      ret= SP_PARSE_ERROR;
    }
    else
    {
      if (dbchanged && (ret= sp_change_db(thd, olddb, 1)))
	goto done;
      *sphp= thd->lex->sphead;
      (*sphp)->set_info((char *)definer, (uint)strlen(definer),
			created, modified, &chistics, sql_mode);
      (*sphp)->optimize();
    }
    thd->lex->sql_command= oldcmd;
    thd->variables.sql_mode= old_sql_mode;
    thd->variables.select_limit= select_limit;
  }

 done:
  if (table)
    close_proc_table(thd);
  DBUG_RETURN(ret);
}


static void
sp_returns_type(THD *thd, String &result, sp_head *sp)
{
  TABLE table;
  Field *field;
  bzero(&table, sizeof(table));
  table.in_use= thd;
  table.s = &table.share_not_to_be_used;
  field= sp->make_field(0, 0, &table);
  field->sql_type(result);
  delete field;
}

static int
db_create_routine(THD *thd, int type, sp_head *sp)
{
  int ret;
  TABLE *table;
  char definer[HOSTNAME_LENGTH+USERNAME_LENGTH+2];
  char olddb[128];
  bool dbchanged;
  DBUG_ENTER("db_create_routine");
  DBUG_PRINT("enter", ("type: %d name: %*s",type,sp->m_name.length,sp->m_name.str));

  dbchanged= FALSE;
  if ((ret= sp_use_new_db(thd, sp->m_db.str, olddb, sizeof(olddb),
			  0, &dbchanged)))
  {
    ret= SP_NO_DB_ERROR;
    goto done;
  }

  if (!(table= open_proc_table_for_update(thd)))
    ret= SP_OPEN_TABLE_FAILED;
  else
  {
    restore_record(table, s->default_values); // Get default values for fields
    strxmov(definer, thd->priv_user, "@", thd->priv_host, NullS);

    if (table->s->fields != MYSQL_PROC_FIELD_COUNT)
    {
      ret= SP_GET_FIELD_FAILED;
      goto done;
    }
    if (sp->m_name.length > table->field[MYSQL_PROC_FIELD_NAME]->field_length)
    {
      ret= SP_BAD_IDENTIFIER;
      goto done;
    }
    table->field[MYSQL_PROC_FIELD_DB]->
      store(sp->m_db.str, sp->m_db.length, system_charset_info);
    table->field[MYSQL_PROC_FIELD_NAME]->
      store(sp->m_name.str, sp->m_name.length, system_charset_info);
    table->field[MYSQL_PROC_FIELD_TYPE]->
      store((longlong)type);
    table->field[MYSQL_PROC_FIELD_SPECIFIC_NAME]->
      store(sp->m_name.str, sp->m_name.length, system_charset_info);
    if (sp->m_chistics->daccess != SP_DEFAULT_ACCESS)
      table->field[MYSQL_PROC_FIELD_ACCESS]->
	store((longlong)sp->m_chistics->daccess);
    table->field[MYSQL_PROC_FIELD_DETERMINISTIC]->
      store((longlong)(sp->m_chistics->detistic ? 1 : 2));
    if (sp->m_chistics->suid != SP_IS_DEFAULT_SUID)
      table->field[MYSQL_PROC_FIELD_SECURITY_TYPE]->
	store((longlong)sp->m_chistics->suid);
    table->field[MYSQL_PROC_FIELD_PARAM_LIST]->
      store(sp->m_params.str, sp->m_params.length, system_charset_info);
    if (sp->m_type == TYPE_ENUM_FUNCTION)
    {
      String retstr(64);
      sp_returns_type(thd, retstr, sp);
      table->field[MYSQL_PROC_FIELD_RETURNS]->
	store(retstr.ptr(), retstr.length(), system_charset_info);
    }
    table->field[MYSQL_PROC_FIELD_BODY]->
      store(sp->m_body.str, sp->m_body.length, system_charset_info);
    table->field[MYSQL_PROC_FIELD_DEFINER]->
      store(definer, (uint)strlen(definer), system_charset_info);
    ((Field_timestamp *)table->field[MYSQL_PROC_FIELD_CREATED])->set_time();
    ((Field_timestamp *)table->field[MYSQL_PROC_FIELD_MODIFIED])->set_time();
    table->field[MYSQL_PROC_FIELD_SQL_MODE]->
      store((longlong)thd->variables.sql_mode);
    if (sp->m_chistics->comment.str)
      table->field[MYSQL_PROC_FIELD_COMMENT]->
	store(sp->m_chistics->comment.str, sp->m_chistics->comment.length,
	      system_charset_info);

    if (!trust_routine_creators && mysql_bin_log.is_open())
    {
      if (!sp->m_chistics->detistic)
      {
	/*
	  Note that for a _function_ this test is not enough; one could use
	  a non-deterministic read-only function in an update statement.
	*/
	enum enum_sp_data_access access=
	  (sp->m_chistics->daccess == SP_DEFAULT_ACCESS) ?
	  SP_DEFAULT_ACCESS_MAPPING : sp->m_chistics->daccess;
	if (access == SP_CONTAINS_SQL ||
	    access == SP_MODIFIES_SQL_DATA)
	{
	  my_message(ER_BINLOG_UNSAFE_ROUTINE,
		     ER(ER_BINLOG_UNSAFE_ROUTINE), MYF(0));
	  ret= SP_INTERNAL_ERROR;
	  goto done;
	}
      }
      if (!(thd->master_access & SUPER_ACL))
      {
	my_message(ER_BINLOG_CREATE_ROUTINE_NEED_SUPER,
		   ER(ER_BINLOG_CREATE_ROUTINE_NEED_SUPER), MYF(0));
	ret= SP_INTERNAL_ERROR;
	goto done;
      }
    }

    ret= SP_OK;
    if (table->file->write_row(table->record[0]))
      ret= SP_WRITE_ROW_FAILED;
    else if (mysql_bin_log.is_open())
    {
      thd->clear_error();
      /* Such a statement can always go directly to binlog, no trans cache */
      Query_log_event qinfo(thd, thd->query, thd->query_length, 0, FALSE);
      mysql_bin_log.write(&qinfo);
    }

  }

done:
  close_thread_tables(thd);
  if (dbchanged)
    (void)sp_change_db(thd, olddb, 1);
  DBUG_RETURN(ret);
}


static int
db_drop_routine(THD *thd, int type, sp_name *name)
{
  TABLE *table;
  int ret;
  DBUG_ENTER("db_drop_routine");
  DBUG_PRINT("enter", ("type: %d name: %*s",
		       type, name->m_name.length, name->m_name.str));

  if (!(table= open_proc_table_for_update(thd)))
    DBUG_RETURN(SP_OPEN_TABLE_FAILED);
  if ((ret= db_find_routine_aux(thd, type, name, table)) == SP_OK)
  {
    if (table->file->delete_row(table->record[0]))
      ret= SP_DELETE_ROW_FAILED;
  }
  close_thread_tables(thd);
  DBUG_RETURN(ret);
}


static int
db_update_routine(THD *thd, int type, sp_name *name, st_sp_chistics *chistics)
{
  TABLE *table;
  int ret;
  bool opened;
  DBUG_ENTER("db_update_routine");
  DBUG_PRINT("enter", ("type: %d name: %*s",
		       type, name->m_name.length, name->m_name.str));

  if (!(table= open_proc_table_for_update(thd)))
    DBUG_RETURN(SP_OPEN_TABLE_FAILED);
  if ((ret= db_find_routine_aux(thd, type, name, table)) == SP_OK)
  {
    store_record(table,record[1]);
    table->timestamp_field_type= TIMESTAMP_NO_AUTO_SET;
    ((Field_timestamp *)table->field[MYSQL_PROC_FIELD_MODIFIED])->set_time();
    if (chistics->suid != SP_IS_DEFAULT_SUID)
      table->field[MYSQL_PROC_FIELD_SECURITY_TYPE]->
	store((longlong)chistics->suid);
    if (chistics->daccess != SP_DEFAULT_ACCESS)
      table->field[MYSQL_PROC_FIELD_ACCESS]->
	store((longlong)chistics->daccess);
    if (chistics->comment.str)
      table->field[MYSQL_PROC_FIELD_COMMENT]->store(chistics->comment.str,
						    chistics->comment.length,
						    system_charset_info);
    if ((table->file->update_row(table->record[1],table->record[0])))
      ret= SP_WRITE_ROW_FAILED;
  }
  close_thread_tables(thd);
  DBUG_RETURN(ret);
}


struct st_used_field
{
  const char *field_name;
  uint field_length;
  enum enum_field_types field_type;
  Field *field;
};

static struct st_used_field init_fields[]=
{
  { "Db",       NAME_LEN, MYSQL_TYPE_STRING,    0},
  { "Name",     NAME_LEN, MYSQL_TYPE_STRING,    0},
  { "Type",            9, MYSQL_TYPE_STRING,    0},
  { "Definer",        77, MYSQL_TYPE_STRING,    0},
  { "Modified",        0, MYSQL_TYPE_TIMESTAMP, 0},
  { "Created",         0, MYSQL_TYPE_TIMESTAMP, 0},
  { "Security_type",   1, MYSQL_TYPE_STRING,    0},
  { "Comment",  NAME_LEN, MYSQL_TYPE_STRING,    0},
  { 0,                 0, MYSQL_TYPE_STRING,    0}
};


static int
print_field_values(THD *thd, TABLE *table,
		   struct st_used_field *used_fields,
		   int type, const char *wild)
{
  Protocol *protocol= thd->protocol;

  if (table->field[MYSQL_PROC_FIELD_TYPE]->val_int() == type)
  {
    String db_string;
    String name_string;
    struct st_used_field *used_field= used_fields;

    if (get_field(thd->mem_root, used_field->field, &db_string))
      db_string.set_ascii("", 0);
    used_field+= 1;
    get_field(thd->mem_root, used_field->field, &name_string);

    if (!wild || !wild[0] || !wild_compare(name_string.ptr(), wild, 0))
    {
      protocol->prepare_for_resend();
      protocol->store(&db_string);
      protocol->store(&name_string);
      for (used_field++;
	   used_field->field_name;
	   used_field++)
      {
	switch (used_field->field_type) {
	case MYSQL_TYPE_TIMESTAMP:
	  {
	    TIME tmp_time;

	    bzero((char *)&tmp_time, sizeof(tmp_time));
	    ((Field_timestamp *) used_field->field)->get_time(&tmp_time);
	    protocol->store(&tmp_time);
	  }
	  break;
	default:
	  {
	    String tmp_string;

	    get_field(thd->mem_root, used_field->field, &tmp_string);
	    protocol->store(&tmp_string);
	  }
	  break;
	}
      }
      if (protocol->write())
	return SP_INTERNAL_ERROR;
    }
  }
  return SP_OK;
}


static int
db_show_routine_status(THD *thd, int type, const char *wild)
{
  TABLE *table;
  TABLE_LIST tables;
  int res;
  DBUG_ENTER("db_show_routine_status");

  memset(&tables, 0, sizeof(tables));
  tables.db= (char*)"mysql";
  tables.table_name= tables.alias= (char*)"proc";

  if (! (table= open_ltable(thd, &tables, TL_READ)))
  {
    res= SP_OPEN_TABLE_FAILED;
    goto done;
  }
  else
  {
    Item *item;
    List<Item> field_list;
    struct st_used_field *used_field;
    TABLE_LIST *leaves= 0;
    st_used_field used_fields[array_elements(init_fields)];

    memcpy((char*) used_fields, (char*) init_fields, sizeof(used_fields));
    /* Init header */
    for (used_field= &used_fields[0];
	 used_field->field_name;
	 used_field++)
    {
      switch (used_field->field_type) {
      case MYSQL_TYPE_TIMESTAMP:
	field_list.push_back(item=new Item_datetime(used_field->field_name));
	break;
      default:
	field_list.push_back(item=new Item_empty_string(used_field->field_name,
							used_field->
							field_length));
	break;
      }
    }
    /* Print header */
    if (thd->protocol->send_fields(&field_list, Protocol::SEND_NUM_ROWS |
                                                Protocol::SEND_EOF))
    {
      res= SP_INTERNAL_ERROR;
      goto err_case;
    }

    /*
      Init fields

      tables is not VIEW for sure => we can pass 0 as condition
    */
    thd->lex->select_lex.context.resolve_in_table_list_only(&tables);
    setup_tables(thd, &thd->lex->select_lex.context,
                 &tables, 0, &leaves, FALSE);
    for (used_field= &used_fields[0];
	 used_field->field_name;
	 used_field++)
    {
      Item_field *field= new Item_field(&thd->lex->select_lex.context,
                                        "mysql", "proc",
					used_field->field_name);
      if (!field ||
          !(used_field->field= find_field_in_tables(thd, field, &tables,
						    0, REPORT_ALL_ERRORS, 1,
                                                    TRUE)))
      {
	res= SP_INTERNAL_ERROR;
	goto err_case1;
      }
    }

    table->file->ha_index_init(0);
    if ((res= table->file->index_first(table->record[0])))
    {
      res= (res == HA_ERR_END_OF_FILE) ? 0 : SP_INTERNAL_ERROR;
      goto err_case1;
    }
    if ((res= print_field_values(thd, table, used_fields, type, wild)))
      goto err_case1;
    while (!table->file->index_next(table->record[0]))
    {
      if ((res= print_field_values(thd, table, used_fields, type, wild)))
	goto err_case1;
    }
    res= SP_OK;
  }

err_case1:
  send_eof(thd);
err_case:
  table->file->ha_index_end();
  close_thread_tables(thd);
done:
  DBUG_RETURN(res);
}


/* Drop all routines in database 'db' */
int
sp_drop_db_routines(THD *thd, char *db)
{
  TABLE *table;
  byte key[64];			// db
  uint keylen;
  int ret;
  DBUG_ENTER("sp_drop_db_routines");
  DBUG_PRINT("enter", ("db: %s", db));

  // Put the key used to read the row together
  keylen= strlen(db);
  if (keylen > 64)
    keylen= 64;
  memcpy(key, db, keylen);
  memset(key+keylen, (int)' ', 64-keylen); // Pad with space
  keylen= sizeof(key);

  ret= SP_OPEN_TABLE_FAILED;
  if (!(table= open_proc_table_for_update(thd)))
    goto err;

  ret= SP_OK;
  table->file->ha_index_init(0);
  if (! table->file->index_read(table->record[0],
				key, keylen, HA_READ_KEY_EXACT))
  {
    int nxtres;
    bool deleted= FALSE;

    do
    {
      if (! table->file->delete_row(table->record[0]))
	deleted= TRUE;		/* We deleted something */
      else
      {
	ret= SP_DELETE_ROW_FAILED;
	nxtres= 0;
	break;
      }
    } while (! (nxtres= table->file->index_next_same(table->record[0],
						     key, keylen)));
    if (nxtres != HA_ERR_END_OF_FILE)
      ret= SP_KEY_NOT_FOUND;
    if (deleted)
      sp_cache_invalidate();
  }
  table->file->ha_index_end();

  close_thread_tables(thd);

err:
  DBUG_RETURN(ret);
}


/*****************************************************************************
  PROCEDURE
******************************************************************************/

/*
  Obtain object representing stored procedure by its name from
  stored procedures cache and looking into mysql.proc if needed.

  SYNOPSIS
    sp_find_procedure()
      thd        - thread context
      name       - name of procedure
      cache_only - if true perform cache-only lookup
                   (Don't look in mysql.proc).

  TODO
    We should consider merging of sp_find_procedure() and
    sp_find_function() into one sp_find_routine() function
    (the same applies to other similarly paired functions).

  RETURN VALUE
    Non-0 pointer to sp_head object for the procedure, or
    0 - in case of error.
*/

sp_head *
sp_find_procedure(THD *thd, sp_name *name, bool cache_only)
{
  sp_head *sp;
  DBUG_ENTER("sp_find_procedure");
  DBUG_PRINT("enter", ("name: %*s.%*s",
		       name->m_db.length, name->m_db.str,
		       name->m_name.length, name->m_name.str));

  if (!(sp= sp_cache_lookup(&thd->sp_proc_cache, name)) && !cache_only)
  {
    if (db_find_routine(thd, TYPE_ENUM_PROCEDURE, name, &sp) == SP_OK)
      sp_cache_insert(&thd->sp_proc_cache, sp);
  }

  DBUG_RETURN(sp);
}


int
sp_exists_routine(THD *thd, TABLE_LIST *tables, bool any, bool no_error)
{
  TABLE_LIST *table;
  bool result= 0;
  DBUG_ENTER("sp_exists_routine");
  for (table= tables; table; table= table->next_global)
  {
    sp_name *name;
    LEX_STRING lex_db;
    LEX_STRING lex_name;
    lex_db.length= strlen(table->db);
    lex_name.length= strlen(table->table_name);
    lex_db.str= thd->strmake(table->db, lex_db.length);
    lex_name.str= thd->strmake(table->table_name, lex_name.length);
    name= new sp_name(lex_db, lex_name);
    name->init_qname(thd);
    if (sp_find_procedure(thd, name) != NULL ||
        sp_find_function(thd, name) != NULL)
    {
      if (any)
        DBUG_RETURN(1);
      result= 1;
    }
    else if (!any)
    {
      if (!no_error)
      {
	my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "FUNCTION or PROCEDURE", 
		 table->table_name);
	DBUG_RETURN(-1);
      }
      DBUG_RETURN(0);
    }
  }
  DBUG_RETURN(result);
}


int
sp_create_procedure(THD *thd, sp_head *sp)
{
  int ret;
  DBUG_ENTER("sp_create_procedure");
  DBUG_PRINT("enter", ("name: %*s", sp->m_name.length, sp->m_name.str));

  ret= db_create_routine(thd, TYPE_ENUM_PROCEDURE, sp);
  DBUG_RETURN(ret);
}


int
sp_drop_procedure(THD *thd, sp_name *name)
{
  int ret;
  bool found;
  DBUG_ENTER("sp_drop_procedure");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  found= sp_cache_remove(&thd->sp_proc_cache, name);
  ret= db_drop_routine(thd, TYPE_ENUM_PROCEDURE, name);
  if (!found && !ret)
    sp_cache_invalidate();
  DBUG_RETURN(ret);
}


int
sp_update_procedure(THD *thd, sp_name *name, st_sp_chistics *chistics)
{
  int ret;
  bool found;
  DBUG_ENTER("sp_update_procedure");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  found= sp_cache_remove(&thd->sp_proc_cache, name);
  ret= db_update_routine(thd, TYPE_ENUM_PROCEDURE, name, chistics);
  if (!found && !ret)
    sp_cache_invalidate();
  DBUG_RETURN(ret);
}


int
sp_show_create_procedure(THD *thd, sp_name *name)
{
  sp_head *sp;
  DBUG_ENTER("sp_show_create_procedure");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  if ((sp= sp_find_procedure(thd, name)))
  {
    int ret= sp->show_create_procedure(thd);

    DBUG_RETURN(ret);
  }

  DBUG_RETURN(SP_KEY_NOT_FOUND);
}


int
sp_show_status_procedure(THD *thd, const char *wild)
{
  int ret;
  DBUG_ENTER("sp_show_status_procedure");

  ret= db_show_routine_status(thd, TYPE_ENUM_PROCEDURE, wild);
  DBUG_RETURN(ret);
}


/*****************************************************************************
  FUNCTION
******************************************************************************/

/*
  Obtain object representing stored function by its name from
  stored functions cache and looking into mysql.proc if needed.

  SYNOPSIS
    sp_find_function()
      thd        - thread context
      name       - name of function
      cache_only - if true perform cache-only lookup
                   (Don't look in mysql.proc).

  NOTE
    See TODO section for sp_find_procedure().

  RETURN VALUE
    Non-0 pointer to sp_head object for the function, or
    0 - in case of error.
*/

sp_head *
sp_find_function(THD *thd, sp_name *name, bool cache_only)
{
  sp_head *sp;
  DBUG_ENTER("sp_find_function");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  if (!(sp= sp_cache_lookup(&thd->sp_func_cache, name)) &&
      !cache_only)
  {
    if (db_find_routine(thd, TYPE_ENUM_FUNCTION, name, &sp) == SP_OK)
      sp_cache_insert(&thd->sp_func_cache, sp);
  }
  DBUG_RETURN(sp);
}


int
sp_create_function(THD *thd, sp_head *sp)
{
  int ret;
  DBUG_ENTER("sp_create_function");
  DBUG_PRINT("enter", ("name: %*s", sp->m_name.length, sp->m_name.str));

  ret= db_create_routine(thd, TYPE_ENUM_FUNCTION, sp);
  DBUG_RETURN(ret);
}


int
sp_drop_function(THD *thd, sp_name *name)
{
  int ret;
  bool found;
  DBUG_ENTER("sp_drop_function");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  found= sp_cache_remove(&thd->sp_func_cache, name);
  ret= db_drop_routine(thd, TYPE_ENUM_FUNCTION, name);
  if (!found && !ret)
    sp_cache_invalidate();
  DBUG_RETURN(ret);
}


int
sp_update_function(THD *thd, sp_name *name, st_sp_chistics *chistics)
{
  int ret;
  bool found;
  DBUG_ENTER("sp_update_procedure");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  found= sp_cache_remove(&thd->sp_func_cache, name);
  ret= db_update_routine(thd, TYPE_ENUM_FUNCTION, name, chistics);
  if (!found && !ret)
    sp_cache_invalidate();
  DBUG_RETURN(ret);
}


int
sp_show_create_function(THD *thd, sp_name *name)
{
  sp_head *sp;
  DBUG_ENTER("sp_show_create_function");
  DBUG_PRINT("enter", ("name: %*s", name->m_name.length, name->m_name.str));

  if ((sp= sp_find_function(thd, name)))
  {
    int ret= sp->show_create_function(thd);

    DBUG_RETURN(ret);
  }
  DBUG_RETURN(SP_KEY_NOT_FOUND);
}


int
sp_show_status_function(THD *thd, const char *wild)
{
  int ret;
  DBUG_ENTER("sp_show_status_function");
  ret= db_show_routine_status(thd, TYPE_ENUM_FUNCTION, wild);
  DBUG_RETURN(ret);
}


/*
  Structure that represents element in the set of stored routines
  used by statement or routine.
*/
struct Sroutine_hash_entry;

struct Sroutine_hash_entry
{
  /* Set key consisting of one-byte routine type and quoted routine name. */
  LEX_STRING key;
  /*
    Next element in list linking all routines in set. See also comments
    for LEX::sroutine/sroutine_list and sp_head::m_sroutines.
  */
  Sroutine_hash_entry *next;
};


extern "C" byte* sp_sroutine_key(const byte *ptr, uint *plen, my_bool first)
{
  Sroutine_hash_entry *rn= (Sroutine_hash_entry *)ptr;
  *plen= rn->key.length;
  return (byte *)rn->key.str;
}


/*
  Check if
   - current statement (the one in thd->lex) needs table prelocking
   - first routine in thd->lex->sroutines_list needs to execute its body in
     prelocked mode.

  SYNOPSIS
    sp_get_prelocking_info()
      thd                  Current thread, thd->lex is the statement to be
                           checked.
      need_prelocking      OUT TRUE  - prelocked mode should be activated
                                       before executing the statement
                               FALSE - Don't activate prelocking 
      first_no_prelocking  OUT TRUE  - Tables used by first routine in
                                       thd->lex->sroutines_list should be
                                       prelocked.
                               FALSE - Otherwise.
  NOTES 
    This function assumes that for any "CALL proc(...)" statement routines_list 
    will have 'proc' as first element (it may have several, consider e.g.
    "proc(sp_func(...)))". This property is currently guaranted by the parser.
*/

void sp_get_prelocking_info(THD *thd, bool *need_prelocking, 
                            bool *first_no_prelocking)
{
  Sroutine_hash_entry *routine;
  routine= (Sroutine_hash_entry*)thd->lex->sroutines_list.first;

  DBUG_ASSERT(routine);
  bool first_is_procedure= (routine->key.str[0] == TYPE_ENUM_PROCEDURE);

  *first_no_prelocking= first_is_procedure;
  *need_prelocking= !first_is_procedure || test(routine->next);
}


/*
  Auxilary function that adds new element to the set of stored routines
  used by statement.

  SYNOPSIS
    add_used_routine()
      lex     - LEX representing statement
      arena   - arena in which memory for new element will be allocated
      key     - key for the hash representing set

  NOTES
    Will also add element to end of 'LEX::sroutines_list' list.

    In case when statement uses stored routines but does not need
    prelocking (i.e. it does not use any tables) we will access the
    elements of LEX::sroutines set on prepared statement re-execution.
    Because of this we have to allocate memory for both hash element
    and copy of its key in persistent arena.

  TODO
    When we will got rid of these accesses on re-executions we will be
    able to allocate memory for hash elements in non-persitent arena
    and directly use key values from sp_head::m_sroutines sets instead
    of making their copies.

  RETURN VALUE
    TRUE  - new element was added.
    FALSE - element was not added (because it is already present in the set).
*/

static bool add_used_routine(LEX *lex, Query_arena *arena,
                             const LEX_STRING *key)
{
  if (!hash_search(&lex->sroutines, (byte *)key->str, key->length))
  {
    Sroutine_hash_entry *rn=
      (Sroutine_hash_entry *)arena->alloc(sizeof(Sroutine_hash_entry) +
                                          key->length);
    if (!rn)              // OOM. Error will be reported using fatal_error().
      return FALSE;
    rn->key.length= key->length;
    rn->key.str= (char *)rn + sizeof(Sroutine_hash_entry);
    memcpy(rn->key.str, key->str, key->length);
    my_hash_insert(&lex->sroutines, (byte *)rn);
    lex->sroutines_list.link_in_list((byte *)rn, (byte **)&rn->next);
    return TRUE;
  }
  return FALSE;
}


/*
  Add routine to the set of stored routines used by statement.

  SYNOPSIS
    sp_add_used_routine()
      lex     - LEX representing statement
      arena   - arena in which memory for new element of the set
                will be allocated
      rt      - routine name
      rt_type - routine type (one of TYPE_ENUM_PROCEDURE/...)

  NOTES
    Will also add element to end of 'LEX::sroutines_list' list.

    To be friendly towards prepared statements one should pass
    persistent arena as second argument.
*/

void sp_add_used_routine(LEX *lex, Query_arena *arena,
                         sp_name *rt, char rt_type)
{
  rt->set_routine_type(rt_type);
  (void)add_used_routine(lex, arena, &rt->m_sroutines_key);
}


/*
  Merge contents of two hashes representing sets of routines used
  by statements or by other routines.

  SYNOPSIS
    sp_update_sp_used_routines()
      dst - hash to which elements should be added
      src - hash from which elements merged

  NOTE
    This procedure won't create new Sroutine_hash_entry objects,
    instead it will simply add elements from source to destination
    hash. Thus time of life of elements in destination hash becomes
    dependant on time of life of elements from source hash. It also
    won't touch lists linking elements in source and destination
    hashes.
*/

void sp_update_sp_used_routines(HASH *dst, HASH *src)
{
  for (uint i=0 ; i < src->records ; i++)
  {
    Sroutine_hash_entry *rt= (Sroutine_hash_entry *)hash_element(src, i);
    if (!hash_search(dst, (byte *)rt->key.str, rt->key.length))
      my_hash_insert(dst, (byte *)rt);
  }
}


/*
  Add contents of hash representing set of routines to the set of
  routines used by statement.

  SYNOPSIS
    sp_update_stmt_used_routines()
      thd - thread context
      lex - LEX representing statement
      src - hash representing set from which routines will be added

  NOTE
    It will also add elements to end of 'LEX::sroutines_list' list.
*/

static void sp_update_stmt_used_routines(THD *thd, LEX *lex, HASH *src)
{
  for (uint i=0 ; i < src->records ; i++)
  {
    Sroutine_hash_entry *rt= (Sroutine_hash_entry *)hash_element(src, i);
    (void)add_used_routine(lex, thd->current_arena, &rt->key);
  }
}


/*
  Cache sub-set of routines used by statement, add tables used by these
  routines to statement table list. Do the same for all routines used
  by these routines.

  SYNOPSIS
    sp_cache_routines_and_add_tables_aux()
      thd              - thread context
      lex              - LEX representing statement
      start            - first routine from the list of routines to be cached
                         (this list defines mentioned sub-set).
      first_no_prelock - If true, don't add tables or cache routines used by
                         the body of the first routine (i.e. *start)
                         will be executed in non-prelocked mode.
  NOTE
    If some function is missing this won't be reported here.
    Instead this fact will be discovered during query execution.

  RETURN VALUE
    TRUE  - some tables were added
    FALSE - no tables were added.
*/

static bool
sp_cache_routines_and_add_tables_aux(THD *thd, LEX *lex,
                                     Sroutine_hash_entry *start, 
                                     bool first_no_prelock)
{
  bool result= FALSE;
  bool first= TRUE;
  DBUG_ENTER("sp_cache_routines_and_add_tables_aux");

  for (Sroutine_hash_entry *rt= start; rt; rt= rt->next)
  {
    sp_name name(rt->key.str, rt->key.length);
    int type= rt->key.str[0];
    sp_head *sp;

    if (!(sp= sp_cache_lookup((type == TYPE_ENUM_FUNCTION ?
                              &thd->sp_func_cache : &thd->sp_proc_cache),
                              &name)))
    {
      LEX *oldlex= thd->lex;
      LEX *newlex= new st_lex;
      thd->lex= newlex;
      newlex->current_select= NULL;
      name.m_name.str= strchr(name.m_qname.str, '.');
      name.m_db.length= name.m_name.str - name.m_qname.str;
      name.m_db.str= strmake_root(thd->mem_root, name.m_qname.str,
                                  name.m_db.length);
      name.m_name.str+= 1;
      name.m_name.length= name.m_qname.length - name.m_db.length - 1;

      if (db_find_routine(thd, type, &name, &sp) == SP_OK)
      {
        if (type == TYPE_ENUM_FUNCTION)
          sp_cache_insert(&thd->sp_func_cache, sp);
        else
          sp_cache_insert(&thd->sp_proc_cache, sp);
      }
      delete newlex;
      thd->lex= oldlex;
    }
    if (sp)
    {
      if (!(first && first_no_prelock))
      {
        sp_update_stmt_used_routines(thd, lex, &sp->m_sroutines);
        result|= sp->add_used_tables_to_table_list(thd, &lex->query_tables_last);
      }
    }
    first= FALSE;
  }
  DBUG_RETURN(result);
}


/*
  Cache all routines from the set of used by statement, add tables used
  by those routines to statement table list. Do the same for all routines
  used by those routines.

  SYNOPSIS
    sp_cache_routines_and_add_tables()
      thd              - thread context
      lex              - LEX representing statement
      first_no_prelock - If true, don't add tables or cache routines used by
                         the body of the first routine (i.e. *start)
                         
  RETURN VALUE
    TRUE  - some tables were added
    FALSE - no tables were added.
*/

bool
sp_cache_routines_and_add_tables(THD *thd, LEX *lex, bool first_no_prelock)
{
  return sp_cache_routines_and_add_tables_aux(thd, lex,
           (Sroutine_hash_entry *)lex->sroutines_list.first,
           first_no_prelock);
}


/*
  Add all routines used by view to the set of routines used by statement.
  Add tables used by those routines to statement table list. Do the same
  for all routines used by these routines.

  SYNOPSIS
    sp_cache_routines_and_add_tables_for_view()
      thd     - thread context
      lex     - LEX representing statement
      aux_lex - LEX representing view
*/

void
sp_cache_routines_and_add_tables_for_view(THD *thd, LEX *lex, LEX *aux_lex)
{
  Sroutine_hash_entry **last_cached_routine_ptr=
                          (Sroutine_hash_entry **)lex->sroutines_list.next;
  sp_update_stmt_used_routines(thd, lex, &aux_lex->sroutines);
  (void)sp_cache_routines_and_add_tables_aux(thd, lex, 
                                             *last_cached_routine_ptr, FALSE);
}


/*
  Add triggers for table to the set of routines used by statement.
  Add tables used by them to statement table list. Do the same for
  all implicitly used routines.

  SYNOPSIS
    sp_cache_routines_and_add_tables_for_triggers()
      thd      - thread context
      lex      - LEX respresenting statement
      triggers - triggers of the table
*/

void
sp_cache_routines_and_add_tables_for_triggers(THD *thd, LEX *lex,
                                              Table_triggers_list *triggers)
{
  if (add_used_routine(lex, thd->current_arena, &triggers->sroutines_key))
  {
    Sroutine_hash_entry **last_cached_routine_ptr=
                            (Sroutine_hash_entry **)lex->sroutines_list.next;
    for (int i= 0; i < (int)TRG_EVENT_MAX; i++)
      for (int j= 0; j < (int)TRG_ACTION_MAX; j++)
        if (triggers->bodies[i][j])
        {
          (void)triggers->bodies[i][j]->add_used_tables_to_table_list(thd,
                                          &lex->query_tables_last);
          sp_update_stmt_used_routines(thd, lex,
                                       &triggers->bodies[i][j]->m_sroutines);
        }

    (void)sp_cache_routines_and_add_tables_aux(thd, lex,
                                               *last_cached_routine_ptr, 
                                               FALSE);
  }
}


/*
 * Generates the CREATE... string from the table information.
 * Returns TRUE on success, FALSE on (alloc) failure.
 */
static bool
create_string(THD *thd, String *buf,
	      int type,
	      sp_name *name,
	      const char *params, ulong paramslen,
	      const char *returns, ulong returnslen,
	      const char *body, ulong bodylen,
	      st_sp_chistics *chistics)
{
  /* Make some room to begin with */
  if (buf->alloc(100 + name->m_qname.length + paramslen + returnslen + bodylen +
		 chistics->comment.length))
    return FALSE;

  buf->append("CREATE ", 7);
  if (type == TYPE_ENUM_FUNCTION)
    buf->append("FUNCTION ", 9);
  else
    buf->append("PROCEDURE ", 10);
  append_identifier(thd, buf, name->m_db.str, name->m_db.length);
  buf->append('.');
  append_identifier(thd, buf, name->m_name.str, name->m_name.length);
  buf->append('(');
  buf->append(params, paramslen);
  buf->append(')');
  if (type == TYPE_ENUM_FUNCTION)
  {
    buf->append(" RETURNS ", 9);
    buf->append(returns, returnslen);
  }
  buf->append('\n');
  switch (chistics->daccess) {
  case SP_NO_SQL:
    buf->append("    NO SQL\n");
    break;
  case SP_READS_SQL_DATA:
    buf->append("    READS SQL DATA\n");
    break;
  case SP_MODIFIES_SQL_DATA:
    buf->append("    MODIFIES SQL DATA\n");
    break;
  case SP_DEFAULT_ACCESS:
  case SP_CONTAINS_SQL:
    /* Do nothing */
    break;
  }
  if (chistics->detistic)
    buf->append("    DETERMINISTIC\n", 18);
  if (chistics->suid == SP_IS_NOT_SUID)
    buf->append("    SQL SECURITY INVOKER\n", 25);
  if (chistics->comment.length)
  {
    buf->append("    COMMENT ");
    append_unescaped(buf, chistics->comment.str, chistics->comment.length);
    buf->append('\n');
  }
  buf->append(body, bodylen);
  return TRUE;
}


//
// Utilities...
//

int
sp_use_new_db(THD *thd, char *newdb, char *olddb, uint olddblen,
	      bool no_access_check, bool *dbchangedp)
{
  bool changeit;
  DBUG_ENTER("sp_use_new_db");
  DBUG_PRINT("enter", ("newdb: %s", newdb));

  if (! newdb)
    newdb= (char *)"";
  if (thd->db && thd->db[0])
  {
    if (my_strcasecmp(system_charset_info, thd->db, newdb) == 0)
      changeit= 0;
    else
    {
      changeit= 1;
      strnmov(olddb, thd->db, olddblen);
    }
  }
  else
  {				// thd->db empty
    if (newdb[0])
      changeit= 1;
    else
      changeit= 0;
    olddb[0] = '\0';
  }
  if (!changeit)
  {
    *dbchangedp= FALSE;
    DBUG_RETURN(0);
  }
  else
  {
    int ret= sp_change_db(thd, newdb, no_access_check);

    if (! ret)
      *dbchangedp= TRUE;
    DBUG_RETURN(ret);
  }
}

/*
  Change database.

  SYNOPSIS
    sp_change_db()
    thd		    Thread handler
    name	    Database name
    empty_is_ok     True= it's ok with "" as name
    no_access_check True= don't do access check

  DESCRIPTION
    This is the same as mysql_change_db(), but with some extra
    arguments for Stored Procedure usage; doing implicit "use" 
    when executing an SP in a different database.
    We also use different error routines, since this might be
    invoked from a function when executing a query or statement.
    Note: We would have prefered to reuse mysql_change_db(), but
      the error handling in particular made that too awkward, so
      we (reluctantly) have a "copy" here.

  RETURN VALUES
    0	ok
    1	error
*/

int
sp_change_db(THD *thd, char *name, bool no_access_check)
{
  int length, db_length;
  char *dbname=my_strdup((char*) name,MYF(MY_WME));
  char	path[FN_REFLEN];
  HA_CREATE_INFO create;
  DBUG_ENTER("sp_change_db");
  DBUG_PRINT("enter", ("db: %s, no_access_check: %d", name, no_access_check));

  db_length= (!dbname ? 0 : strip_sp(dbname));
  if (dbname && db_length)
  {
    if ((db_length > NAME_LEN) || check_db_name(dbname))
    {
      my_error(ER_WRONG_DB_NAME, MYF(0), dbname);
      x_free(dbname);
      DBUG_RETURN(1);
    }
  }

  if (dbname && db_length)
  {
#ifndef NO_EMBEDDED_ACCESS_CHECKS
    if (! no_access_check)
    {
      ulong db_access;

      if (test_all_bits(thd->master_access,DB_ACLS))
	db_access=DB_ACLS;
      else
	db_access= (acl_get(thd->host,thd->ip, thd->priv_user,dbname,0) |
		    thd->master_access);  
      if (!(db_access & DB_ACLS) &&
	  (!grant_option || check_grant_db(thd,dbname)))
      {
	my_error(ER_DBACCESS_DENIED_ERROR, MYF(0),
                 thd->priv_user,
                 thd->priv_host,
                 dbname);
	mysql_log.write(thd,COM_INIT_DB,ER(ER_DBACCESS_DENIED_ERROR),
			thd->priv_user,
			thd->priv_host,
			dbname);
	my_free(dbname,MYF(0));
	DBUG_RETURN(1);
      }
    }
#endif
    (void) sprintf(path,"%s/%s",mysql_data_home,dbname);
    length=unpack_dirname(path,path);		// Convert if not unix
    if (length && path[length-1] == FN_LIBCHAR)
      path[length-1]=0;				// remove ending '\'
    if (access(path,F_OK))
    {
      my_error(ER_BAD_DB_ERROR, MYF(0), dbname);
      my_free(dbname,MYF(0));
      DBUG_RETURN(1);
    }
  }

  x_free(thd->db);
  thd->db=dbname;				// THD::~THD will free this
  thd->db_length=db_length;

  if (dbname && db_length)
  {
    strmov(path+unpack_dirname(path,path), MY_DB_OPT_FILE);
    load_db_opt(thd, path, &create);
    thd->db_charset= create.default_table_charset ?
      create.default_table_charset :
      thd->variables.collation_server;
    thd->variables.collation_database= thd->db_charset;
  }
  DBUG_RETURN(0);
}