path: root/libmysqld/lib_sql.cc

/*
 * Copyright (c)  2000
 * SWsoft  company
 *
 * This material is provided "as is", with absolutely no warranty expressed
 * or implied. Any use is at your own risk.
 *
 * Permission to use or copy this software for any purpose is hereby granted 
 * without fee, provided the above notices are retained on all copies.
 * Permission to modify the code and to distribute modified code is granted,
 * provided the above notices are retained, and a notice that the code was
 * modified is included with the above copyright notice.
 *

  This code was modified by the MySQL team
*/

/*
  The following is needed to not cause conflicts when we include mysqld.cc
*/

#define main main1
#define mysql_unix_port mysql_inix_port1
#define mysql_port mysql_port1

extern "C"
{
  extern unsigned long max_allowed_packet, net_buffer_length;
}

#include "../sql/mysqld.cc"

C_MODE_START

#include <mysql.h>
#undef ER
#include "errmsg.h"
#include <sql_common.h>
#include "embedded_priv.h"

extern unsigned int mysql_server_last_errno;
extern char mysql_server_last_error[MYSQL_ERRMSG_SIZE];
static my_bool emb_read_query_result(MYSQL *mysql);


extern "C" void unireg_clear(int exit_code)
{
  DBUG_ENTER("unireg_clear");
  clean_up(!opt_help && (exit_code || !opt_bootstrap)); /* purecov: inspected */
  my_end(opt_endinfo ? MY_CHECK_ERROR | MY_GIVE_INFO : 0);
  DBUG_VOID_RETURN;
}


/*
  Reads error information from the MYSQL_DATA and puts
  it into proper MYSQL members

  SYNOPSIS
    embedded_get_error()
    mysql        connection handler
    data         query result

  NOTES
    after that function error information will be accessible
       with usual functions like mysql_error()
    data is my_free-d in this function
    most of the data is stored in data->embedded_info structure
*/

void embedded_get_error(MYSQL *mysql, MYSQL_DATA *data)
{
  NET *net= &mysql->net;
  struct embedded_query_result *ei= data->embedded_info;
  net->last_errno= ei->last_errno;
  strmake(net->last_error, ei->info, sizeof(net->last_error)-1);
  memcpy(net->sqlstate, ei->sqlstate, sizeof(net->sqlstate));
  mysql->server_status= ei->server_status;
  my_free(data, MYF(0));
}

static my_bool
emb_advanced_command(MYSQL *mysql, enum enum_server_command command,
		     const uchar *header, ulong header_length,
		     const uchar *arg, ulong arg_length, my_bool skip_check,
                     MYSQL_STMT *stmt)
{
  my_bool result= 1;
  THD *thd=(THD *) mysql->thd;
  NET *net= &mysql->net;
  my_bool stmt_skip= stmt ? stmt->state != MYSQL_STMT_INIT_DONE : FALSE;

  if (!thd)
  {
    /* Do "reconnect" if possible */
    if (mysql_reconnect(mysql) || stmt_skip)
      return 1;
    thd= (THD *) mysql->thd;
  }

#if defined(ENABLED_PROFILING)
  thd->profiling.start_new_query();
#endif

  thd->clear_data_list();
  /* Check that we are calling the client functions in right order */
  if (mysql->status != MYSQL_STATUS_READY)
  {
    set_mysql_error(mysql, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate);
    return 1;
  }

  /* Clear result variables */
  thd->clear_error();
  thd->stmt_da->reset_diagnostics_area();
  mysql->affected_rows= ~(my_ulonglong) 0;
  mysql->field_count= 0;
  net_clear_error(net);
  thd->current_stmt= stmt;

  thd->thread_stack= (char*) &thd;
  thd->store_globals();				// Fix if more than one connect
  /* 
     We have to call free_old_query before we start to fill mysql->fields 
     for new query. In the case of embedded server we collect field data
     during query execution (not during data retrieval as it is in remote
     client). So we have to call free_old_query here
  */
  free_old_query(mysql);

  thd->extra_length= arg_length;
  thd->extra_data= (char *)arg;
  if (header)
  {
    arg= header;
    arg_length= header_length;
  }

  result= dispatch_command(command, thd, (char *) arg, arg_length);
  thd->cur_data= 0;
  thd->mysys_var= NULL;

  if (!skip_check)
    result= thd->is_error() ? -1 : 0;

  thd->mysys_var= 0;

#if defined(ENABLED_PROFILING)
  thd->profiling.finish_current_query();
#endif
  return result;
}

static void emb_flush_use_result(MYSQL *mysql, my_bool)
{
  THD *thd= (THD*) mysql->thd;
  if (thd->cur_data)
  {
    free_rows(thd->cur_data);
    thd->cur_data= 0;
  }
  else if (thd->first_data)
  {
    MYSQL_DATA *data= thd->first_data;
    thd->first_data= data->embedded_info->next;
    free_rows(data);
  }
}


/*
  reads dataset from the next query result

  SYNOPSIS
  emb_read_rows()
  mysql		connection handle
  other parameters are not used

  NOTES
    It just gets next MYSQL_DATA from the result's queue

  RETURN
    pointer to MYSQL_DATA with the coming recordset
*/

static MYSQL_DATA *
emb_read_rows(MYSQL *mysql, MYSQL_FIELD *mysql_fields __attribute__((unused)),
	      unsigned int fields __attribute__((unused)))
{
  MYSQL_DATA *result= ((THD*)mysql->thd)->cur_data;
  ((THD*)mysql->thd)->cur_data= 0;
  if (result->embedded_info->last_errno)
  {
    embedded_get_error(mysql, result);
    return NULL;
  }
  *result->embedded_info->prev_ptr= NULL;
  return result;
}


static MYSQL_FIELD *emb_list_fields(MYSQL *mysql)
{
  MYSQL_DATA *res;
  if (emb_read_query_result(mysql))
    return 0;
  res= ((THD*) mysql->thd)->cur_data;
  ((THD*) mysql->thd)->cur_data= 0;
  mysql->field_alloc= res->alloc;
  my_free(res,MYF(0));
  mysql->status= MYSQL_STATUS_READY;
  return mysql->fields;
}

static my_bool emb_read_prepare_result(MYSQL *mysql, MYSQL_STMT *stmt)
{
  THD *thd= (THD*) mysql->thd;
  MYSQL_DATA *res;

  stmt->stmt_id= thd->client_stmt_id;
  stmt->param_count= thd->client_param_count;
  stmt->field_count= 0;
  mysql->warning_count= thd->warning_info->statement_warn_count();

  if (thd->first_data)
  {
    if (emb_read_query_result(mysql))
      return 1;
    stmt->field_count= mysql->field_count;
    mysql->status= MYSQL_STATUS_READY;
    res= thd->cur_data;
    thd->cur_data= NULL;
    if (!(mysql->server_status & SERVER_STATUS_AUTOCOMMIT))
      mysql->server_status|= SERVER_STATUS_IN_TRANS;

    stmt->fields= mysql->fields;
    stmt->mem_root= res->alloc;
    mysql->fields= NULL;
    my_free(res,MYF(0));
  }

  return 0;
}

/**************************************************************************
  Get column lengths of the current row
  If one uses mysql_use_result, res->lengths contains the length information,
  else the lengths are calculated from the offset between pointers.
**************************************************************************/

static void emb_fetch_lengths(ulong *to, MYSQL_ROW column,
			      unsigned int field_count)
{ 
  MYSQL_ROW end;

  for (end=column + field_count; column != end ; column++,to++)
    *to= *column ? *(uint *)((*column) - sizeof(uint)) : 0;
}

static my_bool emb_read_query_result(MYSQL *mysql)
{
  THD *thd= (THD*) mysql->thd;
  MYSQL_DATA *res= thd->first_data;
  DBUG_ASSERT(!thd->cur_data);
  thd->first_data= res->embedded_info->next;
  if (res->embedded_info->last_errno &&
      !res->embedded_info->fields_list)
  {
    embedded_get_error(mysql, res);
    return 1;
  }

  mysql->warning_count= res->embedded_info->warning_count;
  mysql->server_status= res->embedded_info->server_status;
  mysql->field_count= res->fields;
  if (!(mysql->fields= res->embedded_info->fields_list))
  {
    mysql->affected_rows= res->embedded_info->affected_rows;
    mysql->insert_id= res->embedded_info->insert_id;
  }
  net_clear_error(&mysql->net);
  mysql->info= 0;

  if (res->embedded_info->info[0])
  {
    strmake(mysql->info_buffer, res->embedded_info->info, MYSQL_ERRMSG_SIZE-1);
    mysql->info= mysql->info_buffer;
  }

  if (res->embedded_info->fields_list)
  {
    mysql->status=MYSQL_STATUS_GET_RESULT;
    thd->cur_data= res;
  }
  else
    my_free(res, MYF(0));

  return 0;
}

static int emb_stmt_execute(MYSQL_STMT *stmt)
{
  DBUG_ENTER("emb_stmt_execute");
  uchar header[5];
  THD *thd;
  my_bool res;

  int4store(header, stmt->stmt_id);
  header[4]= (uchar) stmt->flags;
  thd= (THD*)stmt->mysql->thd;
  thd->client_param_count= stmt->param_count;
  thd->client_params= stmt->params;

  res= test(emb_advanced_command(stmt->mysql, COM_STMT_EXECUTE, 0, 0,
                                 header, sizeof(header), 1, stmt) ||
            emb_read_query_result(stmt->mysql));
  stmt->affected_rows= stmt->mysql->affected_rows;
  stmt->insert_id= stmt->mysql->insert_id;
  stmt->server_status= stmt->mysql->server_status;
  if (res)
  {
    NET *net= &stmt->mysql->net;
    set_stmt_errmsg(stmt, net);
    DBUG_RETURN(1);
  }
  DBUG_RETURN(0);
}

int emb_read_binary_rows(MYSQL_STMT *stmt)
{
  MYSQL_DATA *data;
  if (!(data= emb_read_rows(stmt->mysql, 0, 0)))
  {
    set_stmt_errmsg(stmt, &stmt->mysql->net);
    return 1;
  }
  stmt->result= *data;
  my_free((char *) data, MYF(0));
  set_stmt_errmsg(stmt, &stmt->mysql->net);
  return 0;
}

int emb_read_rows_from_cursor(MYSQL_STMT *stmt)
{
  MYSQL *mysql= stmt->mysql;
  THD *thd= (THD*) mysql->thd;
  MYSQL_DATA *res= thd->first_data;
  DBUG_ASSERT(!thd->first_data->embedded_info->next);
  thd->first_data= 0;
  if (res->embedded_info->last_errno)
  {
    embedded_get_error(mysql, res);
    set_stmt_errmsg(stmt, &mysql->net);
    return 1;
  }

  thd->cur_data= res;
  mysql->warning_count= res->embedded_info->warning_count;
  mysql->server_status= res->embedded_info->server_status;
  net_clear_error(&mysql->net);

  return emb_read_binary_rows(stmt);
}

int emb_unbuffered_fetch(MYSQL *mysql, char **row)
{
  THD *thd= (THD*) mysql->thd;
  MYSQL_DATA *data= thd->cur_data;
  if (data && data->embedded_info->last_errno)
  {
    embedded_get_error(mysql, data);
    thd->cur_data= 0;
    return 1;
  }
  if (!data || !data->data)
  {
    *row= NULL;
    if (data)
    {
      thd->cur_data= thd->first_data;
      thd->first_data= data->embedded_info->next;
      free_rows(data);
    }
  }
  else
  {
    *row= (char *)data->data->data;
    data->data= data->data->next;
  }
  return 0;
}

static void emb_free_embedded_thd(MYSQL *mysql)
{
  THD *thd= (THD*)mysql->thd;
  thd->clear_data_list();
  thread_count--;
  thd->store_globals();
  thd->unlink();
  delete thd;
  my_pthread_setspecific_ptr(THR_THD,  0);
  mysql->thd=0;
}

static const char * emb_read_statistics(MYSQL *mysql)
{
  THD *thd= (THD*)mysql->thd;
  return thd->is_error() ? thd->stmt_da->message() : "";
}


static MYSQL_RES * emb_store_result(MYSQL *mysql)
{
  return mysql_store_result(mysql);
}

int emb_read_change_user_result(MYSQL *mysql, 
				char *buff __attribute__((unused)),
				const char *passwd __attribute__((unused)))
{
  return mysql_errno(mysql);
}

MYSQL_METHODS embedded_methods= 
{
  emb_read_query_result,
  emb_advanced_command,
  emb_read_rows,
  emb_store_result,
  emb_fetch_lengths, 
  emb_flush_use_result,
  emb_list_fields,
  emb_read_prepare_result,
  emb_stmt_execute,
  emb_read_binary_rows,
  emb_unbuffered_fetch,
  emb_free_embedded_thd,
  emb_read_statistics,
  emb_read_query_result,
  emb_read_change_user_result,
  emb_read_rows_from_cursor
};

/*
  Make a copy of array and the strings array points to
*/

char **copy_arguments(int argc, char **argv)
{
  uint length= 0;
  char **from, **res, **end= argv+argc;

  for (from=argv ; from != end ; from++)
    length+= strlen(*from);

  if ((res= (char**) my_malloc(sizeof(argv)*(argc+1)+length+argc,
			       MYF(MY_WME))))
  {
    char **to= res, *to_str= (char*) (res+argc+1);
    for (from=argv ; from != end ;)
    {
      *to++= to_str;
      to_str= strmov(to_str, *from++)+1;
    }
    *to= 0;					// Last ptr should be null
  }
  return res;
}

char **		copy_arguments_ptr= 0;

int init_embedded_server(int argc, char **argv, char **groups)
{
  /*
    This mess is to allow people to call the init function without
    having to mess with a fake argv
   */
  int *argcp;
  char ***argvp;
  int fake_argc = 1;
  char *fake_argv[] = { (char *)"", 0 };
  const char *fake_groups[] = { "server", "embedded", 0 };
  my_bool acl_error;
  if (argc)
  {
    argcp= &argc;
    argvp= (char***) &argv;
  }
  else
  {
    argcp= &fake_argc;
    argvp= (char ***) &fake_argv;
  }
  if (!groups)
    groups= (char**) fake_groups;

  my_progname= (char *)"mysql_embedded";

  /*
    Perform basic logger initialization logger. Should be called after
    MY_INIT, as it initializes mutexes. Log tables are inited later.
  */
  logger.init_base();

  orig_argc= *argcp;
  orig_argv= *argvp;
  load_defaults("my", (const char **)groups, argcp, argvp);
  defaults_argc= *argcp;
  defaults_argv= *argvp;
  remaining_argc= argc;
  remaining_argv= argv;

  /* Must be initialized early for comparison of options name */
  system_charset_info= &my_charset_utf8_general_ci;
  sys_var_init();

  if (init_common_variables())
  {
    mysql_server_end();
    return 1;
  }

  mysql_data_home= mysql_real_data_home;
  mysql_data_home_len= mysql_real_data_home_len;
    
  /* Get default temporary directory */
  opt_mysql_tmpdir=getenv("TMPDIR");	/* Use this if possible */
#if defined( __WIN__) || defined(OS2)
  if (!opt_mysql_tmpdir)
    opt_mysql_tmpdir=getenv("TEMP");
  if (!opt_mysql_tmpdir)
    opt_mysql_tmpdir=getenv("TMP");
#endif
  if (!opt_mysql_tmpdir || !opt_mysql_tmpdir[0])
    opt_mysql_tmpdir=(char*) P_tmpdir;		/* purecov: inspected */

  init_ssl();
  umask(((~my_umask) & 0666));
  if (init_server_components())
  {
    mysql_server_end();
    return 1;
  }

  error_handler_hook = my_message_sql;

  acl_error= 0;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  if (!(acl_error= acl_init(opt_noacl)) &&
      !opt_noacl)
    (void) grant_init();
#endif
  if (acl_error || my_tz_init((THD *)0, default_tz_name, opt_bootstrap))
  {
    mysql_server_end();
    return 1;
  }

  init_max_user_conn();
  init_update_queries();

#ifdef HAVE_DLOPEN
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  if (!opt_noacl)
#endif
    udf_init();
#endif

  (void) thr_setconcurrency(concurrency);	// 10 by default

  start_handle_manager();

  // FIXME initialize binlog_filter and rpl_filter if not already done
  //       corresponding delete is in clean_up()
  if(!binlog_filter) binlog_filter = new Rpl_filter;
  if(!rpl_filter) rpl_filter = new Rpl_filter;

  if (opt_init_file)
  {
    if (read_init_file(opt_init_file))
    {
      mysql_server_end();
      return 1;
    }
  }

  execute_ddl_log_recovery();
  return 0;
}

void end_embedded_server()
{
  my_free((char*) copy_arguments_ptr, MYF(MY_ALLOW_ZERO_PTR));
  copy_arguments_ptr=0;
  clean_up(0);
}


void init_embedded_mysql(MYSQL *mysql, int client_flag)
{
  THD *thd = (THD *)mysql->thd;
  thd->mysql= mysql;
  mysql->server_version= server_version;
  init_alloc_root(&mysql->field_alloc, 8192, 0);
}

/**
  @brief Initialize a new THD for a connection in the embedded server

  @param client_flag  Client capabilities which this thread supports
  @return pointer to the created THD object

  @todo
  This function copies code from several places in the server, including
  create_new_thread(), and prepare_new_connection_state().  This should
  be refactored to avoid code duplication.
*/
void *create_embedded_thd(int client_flag)
{
  THD * thd= new THD;
  thd->thread_id= thd->variables.pseudo_thread_id= thread_id++;

  thd->thread_stack= (char*) &thd;
  if (thd->store_globals())
  {
    fprintf(stderr,"store_globals failed.\n");
    goto err;
  }
  lex_start(thd);

  /* TODO - add init_connect command execution */

  if (thd->variables.max_join_size == HA_POS_ERROR)
    thd->variables.option_bits |= OPTION_BIG_SELECTS;
  thd->proc_info=0;				// Remove 'login'
  thd->command=COM_SLEEP;
  thd->set_time();
  thd->init_for_queries();
  thd->client_capabilities= client_flag;
  thd->real_id= pthread_self();

  thd->db= NULL;
  thd->db_length= 0;
#ifndef NO_EMBEDDED_ACCESS_CHECKS
  thd->security_ctx->db_access= DB_ACLS;
  thd->security_ctx->master_access= ~NO_ACCESS;
#endif
  thd->cur_data= 0;
  thd->first_data= 0;
  thd->data_tail= &thd->first_data;
  bzero((char*) &thd->net, sizeof(thd->net));

  thread_count++;
  threads.append(thd);
  thd->mysys_var= 0;
  return thd;
err:
  delete(thd);
  return NULL;
}


#ifdef NO_EMBEDDED_ACCESS_CHECKS
int check_embedded_connection(MYSQL *mysql, const char *db)
{
  int result;
  THD *thd= (THD*)mysql->thd;
  thd_init_client_charset(thd, mysql->charset->number);
  thd->update_charset();
  Security_context *sctx= thd->security_ctx;
  sctx->host_or_ip= sctx->host= (char*) my_localhost;
  strmake(sctx->priv_host, (char*) my_localhost,  MAX_HOSTNAME-1);
  sctx->priv_user= sctx->user= my_strdup(mysql->user, MYF(0));
  result= check_user(thd, COM_CONNECT, NULL, 0, db, true);
  thd->protocol->end_statement();
  emb_read_query_result(mysql);
  return result;
}

#else
int check_embedded_connection(MYSQL *mysql, const char *db)
{
  THD *thd= (THD*)mysql->thd;
  Security_context *sctx= thd->security_ctx;
  int result;
  char scramble_buff[SCRAMBLE_LENGTH];
  int passwd_len;

  thd_init_client_charset(thd, mysql->charset->number);
  thd->update_charset();
  if (mysql->options.client_ip)
  {
    sctx->host= my_strdup(mysql->options.client_ip, MYF(0));
    sctx->ip= my_strdup(sctx->host, MYF(0));
  }
  else
    sctx->host= (char*)my_localhost;
  sctx->host_or_ip= sctx->host;

  if (acl_check_host(sctx->host, sctx->ip))
  {
    result= ER_HOST_NOT_PRIVILEGED;
    goto err;
  }

  sctx->user= my_strdup(mysql->user, MYF(0));
  if (mysql->passwd && mysql->passwd[0])
  {
    memset(thd->scramble, 55, SCRAMBLE_LENGTH); // dummy scramble
    thd->scramble[SCRAMBLE_LENGTH]= 0;
    scramble(scramble_buff, thd->scramble, mysql->passwd);
    passwd_len= SCRAMBLE_LENGTH;
  }
  else
    passwd_len= 0;

  if((result= check_user(thd, COM_CONNECT, 
			 scramble_buff, passwd_len, db, true)))
     goto err;

  return 0;
err:
  {
    NET *net= &mysql->net;
    strmake(net->last_error, thd->stmt_da->message(),
            sizeof(net->last_error)-1);
    memcpy(net->sqlstate,
           mysql_errno_to_sqlstate(thd->stmt_da->sql_errno()),
           sizeof(net->sqlstate)-1);
  }
  return result;
}
#endif

C_MODE_END

void THD::clear_data_list()
{
  while (first_data)
  {
    MYSQL_DATA *data= first_data;
    first_data= data->embedded_info->next;
    free_rows(data);
  }
  data_tail= &first_data;
  free_rows(cur_data);
  cur_data= 0;
}


static char *dup_str_aux(MEM_ROOT *root, const char *from, uint length,
			 CHARSET_INFO *fromcs, CHARSET_INFO *tocs)
{
  uint32 dummy32;
  uint dummy_err;
  char *result;

  /* 'tocs' is set 0 when client issues SET character_set_results=NULL */
  if (tocs && String::needs_conversion(0, fromcs, tocs, &dummy32))
  {
    uint new_len= (tocs->mbmaxlen * length) / fromcs->mbminlen + 1;
    result= (char *)alloc_root(root, new_len);
    length= copy_and_convert(result, new_len,
                             tocs, from, length, fromcs, &dummy_err);
  }
  else
  {
    result= (char *)alloc_root(root, length + 1);
    memcpy(result, from, length);
  }

  result[length]= 0;
  return result;
}


/*
  creates new result and hooks it to the list

  SYNOPSIS
  alloc_new_dataset()

  NOTES
    allocs the MYSQL_DATA + embedded_query_result couple
    to store the next query result,
    links these two and attach it to the THD::data_tail

  RETURN
    pointer to the newly created query result
*/

MYSQL_DATA *THD::alloc_new_dataset()
{
  MYSQL_DATA *data;
  struct embedded_query_result *emb_data;
  if (!my_multi_malloc(MYF(MY_WME | MY_ZEROFILL),
                       &data, sizeof(*data),
                       &emb_data, sizeof(*emb_data),
                       NULL))
    return NULL;

  emb_data->prev_ptr= &data->data;
  cur_data= data;
  *data_tail= data;
  data_tail= &emb_data->next;
  data->embedded_info= emb_data;
  return data;
}


/**
  Stores server_status and warning_count in the current
  query result structures.

  @param thd            current thread

  @note Should be called after we get the recordset-result.
*/

static
bool
write_eof_packet(THD *thd, uint server_status, uint statement_warn_count)
{
  if (!thd->mysql)            // bootstrap file handling
    return FALSE;
  /*
    The following test should never be true, but it's better to do it
    because if 'is_fatal_error' is set the server is not going to execute
    other queries (see the if test in dispatch_command / COM_QUERY)
  */
  if (thd->is_fatal_error)
    thd->server_status&= ~SERVER_MORE_RESULTS_EXISTS;
  thd->cur_data->embedded_info->server_status= server_status;
  /*
    Don't send warn count during SP execution, as the warn_list
    is cleared between substatements, and mysqltest gets confused
  */
  thd->cur_data->embedded_info->warning_count=
    (thd->spcont ? 0 : min(statement_warn_count, 65535));
  return FALSE;
}


/*
  allocs new query result and initialises Protocol::alloc

  SYNOPSIS
  Protocol::begin_dataset()

  RETURN
    0 if success
    1 if memory allocation failed
*/

int Protocol::begin_dataset()
{
  MYSQL_DATA *data= thd->alloc_new_dataset();
  if (!data)
    return 1;
  alloc= &data->alloc;
  init_alloc_root(alloc,8192,0);	/* Assume rowlength < 8192 */
  alloc->min_malloc=sizeof(MYSQL_ROWS);
  return 0;
}


/*
  remove last row of current recordset

  SYNOPSIS
  Protocol_text::remove_last_row()

  NOTES
    does the loop from the beginning of the current recordset to
    the last record and cuts it off.
    Not supposed to be frequently called.
*/

void Protocol_text::remove_last_row()
{
  MYSQL_DATA *data= thd->cur_data;
  MYSQL_ROWS **last_row_hook= &data->data;
  my_ulonglong count= data->rows;
  DBUG_ENTER("Protocol_text::remove_last_row");
  while (--count)
    last_row_hook= &(*last_row_hook)->next;

  *last_row_hook= 0;
  data->embedded_info->prev_ptr= last_row_hook;
  data->rows--;

  DBUG_VOID_RETURN;
}


bool Protocol::send_result_set_metadata(List<Item> *list, uint flags)
{
  List_iterator_fast<Item> it(*list);
  Item                     *item;
  MYSQL_FIELD              *client_field;
  MEM_ROOT                 *field_alloc;
  CHARSET_INFO             *thd_cs= thd->variables.character_set_results;
  CHARSET_INFO             *cs= system_charset_info;
  MYSQL_DATA               *data;
  DBUG_ENTER("send_result_set_metadata");

  if (!thd->mysql)            // bootstrap file handling
    DBUG_RETURN(0);

  if (begin_dataset())
    goto err;

  data= thd->cur_data;
  data->fields= field_count= list->elements;
  field_alloc= &data->alloc;

  if (!(client_field= data->embedded_info->fields_list= 
	(MYSQL_FIELD*)alloc_root(field_alloc, sizeof(MYSQL_FIELD)*field_count)))
    goto err;

  while ((item= it++))
  {
    Send_field server_field;
    item->make_field(&server_field);

    /* Keep things compatible for old clients */
    if (server_field.type == MYSQL_TYPE_VARCHAR)
      server_field.type= MYSQL_TYPE_VAR_STRING;

    client_field->db= dup_str_aux(field_alloc, server_field.db_name,
                                  strlen(server_field.db_name), cs, thd_cs);
    client_field->table= dup_str_aux(field_alloc, server_field.table_name,
                                     strlen(server_field.table_name), cs, thd_cs);
    client_field->name= dup_str_aux(field_alloc, server_field.col_name,
                                    strlen(server_field.col_name), cs, thd_cs);
    client_field->org_table= dup_str_aux(field_alloc, server_field.org_table_name,
                                         strlen(server_field.org_table_name), cs, thd_cs);
    client_field->org_name= dup_str_aux(field_alloc, server_field.org_col_name,
                                        strlen(server_field.org_col_name), cs, thd_cs);
    if (item->charset_for_protocol() == &my_charset_bin || thd_cs == NULL)
    {
      /* No conversion */
      client_field->charsetnr= item->charset_for_protocol()->number;
      client_field->length= server_field.length;
    }
    else
    {
      uint max_char_len;
      /* With conversion */
      client_field->charsetnr= thd_cs->number;
      max_char_len= (server_field.type >= (int) MYSQL_TYPE_TINY_BLOB &&
                     server_field.type <= (int) MYSQL_TYPE_BLOB) ?
                     server_field.length / item->collation.collation->mbminlen :
                     server_field.length / item->collation.collation->mbmaxlen;
      client_field->length= char_to_byte_length_safe(max_char_len,
                                                     thd_cs->mbmaxlen);
    }
    client_field->type=   server_field.type;
    client_field->flags= server_field.flags;
    client_field->decimals= server_field.decimals;
    client_field->db_length=		strlen(client_field->db);
    client_field->table_length=		strlen(client_field->table);
    client_field->name_length=		strlen(client_field->name);
    client_field->org_name_length=	strlen(client_field->org_name);
    client_field->org_table_length=	strlen(client_field->org_table);

    client_field->catalog= dup_str_aux(field_alloc, "def", 3, cs, thd_cs);
    client_field->catalog_length= 3;

    if (IS_NUM(client_field->type))
      client_field->flags|= NUM_FLAG;

    if (flags & (int) Protocol::SEND_DEFAULTS)
    {
      char buff[80];
      String tmp(buff, sizeof(buff), default_charset_info), *res;

      if (!(res=item->val_str(&tmp)))
      {
	client_field->def_length= 0;
	client_field->def= strmake_root(field_alloc, "",0);
      }
      else
      {
	client_field->def_length= res->length();
	client_field->def= strmake_root(field_alloc, res->ptr(),
					client_field->def_length);
      }
    }
    else
      client_field->def=0;
    client_field->max_length= 0;
    ++client_field;
  }

  if (flags & SEND_EOF)
    write_eof_packet(thd, thd->server_status,
                     thd->warning_info->statement_warn_count());

  DBUG_RETURN(prepare_for_send(list->elements));
 err:
  my_error(ER_OUT_OF_RESOURCES, MYF(0));        /* purecov: inspected */
  DBUG_RETURN(1);				/* purecov: inspected */
}

bool Protocol::write()
{
  if (!thd->mysql)            // bootstrap file handling
    return false;

  *next_field= 0;
  return false;
}

bool Protocol_binary::write()
{
  MYSQL_ROWS *cur;
  MYSQL_DATA *data= thd->cur_data;

  data->rows++;
  if (!(cur= (MYSQL_ROWS *)alloc_root(alloc,
                                      sizeof(MYSQL_ROWS)+packet->length())))
  {
    my_error(ER_OUT_OF_RESOURCES,MYF(0));
    return true;
  }
  cur->data= (MYSQL_ROW)(((char *)cur) + sizeof(MYSQL_ROWS));
  memcpy(cur->data, packet->ptr()+1, packet->length()-1);
  cur->length= packet->length();       /* To allow us to do sanity checks */

  *data->embedded_info->prev_ptr= cur;
  data->embedded_info->prev_ptr= &cur->next;
  cur->next= 0;
  
  return false;
}


/**
  Embedded library implementation of OK response.

  This function is used by the server to write 'OK' packet to
  the "network" when the server is compiled as an embedded library.
  Since there is no network in the embedded configuration,
  a different implementation is necessary.
  Instead of marshalling response parameters to a network representation
  and then writing it to the socket, here we simply copy the data to the
  corresponding client-side connection structures. 

  @sa Server implementation of net_send_ok in protocol.cc for
  description of the arguments.

  @return
    @retval TRUE An error occurred
    @retval FALSE Success
*/

bool
net_send_ok(THD *thd,
            uint server_status, uint statement_warn_count,
            ulonglong affected_rows, ulonglong id, const char *message)
{
  DBUG_ENTER("emb_net_send_ok");
  MYSQL_DATA *data;
  MYSQL *mysql= thd->mysql;

  if (!mysql)            // bootstrap file handling
    DBUG_RETURN(FALSE);
  if (!(data= thd->alloc_new_dataset()))
    DBUG_RETURN(TRUE);
  data->embedded_info->affected_rows= affected_rows;
  data->embedded_info->insert_id= id;
  if (message)
    strmake(data->embedded_info->info, message,
            sizeof(data->embedded_info->info)-1);

  bool error= write_eof_packet(thd, server_status, statement_warn_count);
  thd->cur_data= 0;
  DBUG_RETURN(error);
}


/**
  Embedded library implementation of EOF response.

  @sa net_send_ok

  @return
    @retval TRUE  An error occurred
    @retval FALSE Success
*/

bool
net_send_eof(THD *thd, uint server_status, uint statement_warn_count)
{
  bool error= write_eof_packet(thd, server_status, statement_warn_count);
  thd->cur_data= 0;
  return error;
}


bool net_send_error_packet(THD *thd, uint sql_errno, const char *err,
                           const char *sqlstate)
{
  uint error;
  uchar converted_err[MYSQL_ERRMSG_SIZE];
  uint32 converted_err_len;
  MYSQL_DATA *data= thd->cur_data;
  struct embedded_query_result *ei;

  if (!thd->mysql)            // bootstrap file handling
  {
    fprintf(stderr, "ERROR: %d  %s\n", sql_errno, err);
    return TRUE;
  }

  if (!data)
    data= thd->alloc_new_dataset();

  ei= data->embedded_info;
  ei->last_errno= sql_errno;
  converted_err_len= convert_error_message((char*)converted_err,
                                           sizeof(converted_err),
                                           thd->variables.character_set_results,
                                           err, strlen(err),
                                           system_charset_info, &error);
  strmake(ei->info, (const char*) converted_err, sizeof(ei->info)-1);
  strmov(ei->sqlstate, sqlstate);
  ei->server_status= thd->server_status;
  thd->cur_data= 0;
  return FALSE;
}


void Protocol_text::prepare_for_resend()
{
  MYSQL_ROWS *cur;
  MYSQL_DATA *data= thd->cur_data;
  DBUG_ENTER("send_data");

  if (!thd->mysql)            // bootstrap file handling
    DBUG_VOID_RETURN;

  data->rows++;
  if (!(cur= (MYSQL_ROWS *)alloc_root(alloc, sizeof(MYSQL_ROWS)+(field_count + 1) * sizeof(char *))))
  {
    my_error(ER_OUT_OF_RESOURCES,MYF(0));
    DBUG_VOID_RETURN;
  }
  cur->data= (MYSQL_ROW)(((char *)cur) + sizeof(MYSQL_ROWS));

  *data->embedded_info->prev_ptr= cur;
  data->embedded_info->prev_ptr= &cur->next;
  next_field=cur->data;
  next_mysql_field= data->embedded_info->fields_list;
#ifndef DBUG_OFF
  field_pos= 0;
#endif

  DBUG_VOID_RETURN;
}

bool Protocol_text::store_null()
{
  *(next_field++)= NULL;
  ++next_mysql_field;
  return false;
}

bool Protocol::net_store_data(const uchar *from, size_t length)
{
  char *field_buf;
  if (!thd->mysql)            // bootstrap file handling
    return FALSE;

  if (!(field_buf= (char*) alloc_root(alloc, length + sizeof(uint) + 1)))
    return TRUE;
  *(uint *)field_buf= length;
  *next_field= field_buf + sizeof(uint);
  memcpy((uchar*) *next_field, from, length);
  (*next_field)[length]= 0;
  if (next_mysql_field->max_length < length)
    next_mysql_field->max_length=length;
  ++next_field;
  ++next_mysql_field;
  return FALSE;
}

#if defined(_MSC_VER) && _MSC_VER < 1400
#define vsnprintf _vsnprintf
#endif

int vprint_msg_to_log(enum loglevel level __attribute__((unused)),
                       const char *format, va_list argsi)
{
  vsnprintf(mysql_server_last_error, sizeof(mysql_server_last_error),
           format, argsi);
  mysql_server_last_errno= CR_UNKNOWN_ERROR;
  return 0;
}


bool Protocol::net_store_data(const uchar *from, size_t length,
                              CHARSET_INFO *from_cs, CHARSET_INFO *to_cs)
{
  uint conv_length= to_cs->mbmaxlen * length / from_cs->mbminlen;
  uint dummy_error;
  char *field_buf;
  if (!thd->mysql)            // bootstrap file handling
    return false;

  if (!(field_buf= (char*) alloc_root(alloc, conv_length + sizeof(uint) + 1)))
    return true;
  *next_field= field_buf + sizeof(uint);
  length= copy_and_convert(*next_field, conv_length, to_cs,
                           (const char*) from, length, from_cs, &dummy_error);
  *(uint *) field_buf= length;
  (*next_field)[length]= 0;
  if (next_mysql_field->max_length < length)
    next_mysql_field->max_length= length;
  ++next_field;
  ++next_mysql_field;
  return false;
}