~drizzle-trunk/drizzle/development

/* Copyright (C) 2000-2003 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

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

/*
  This file is included by both libmysql.c (the MySQL client C API)
  and the mysqld server to connect to another MYSQL server.

  The differences for the two cases are:

  - Things that only works for the client:
  - Trying to automaticly determinate user name if not supplied to
    mysql_real_connect()
  - Support for reading local file with LOAD DATA LOCAL
  - SHARED memory handling
  - Protection against sigpipe
  - Prepared statements
  
  - Things that only works for the server
  - Alarm handling on connect
  
  In all other cases, the code should be idential for the client and
  server.
*/ 

#include <my_global.h>

#include "mysql.h"

#include <netdb.h>

/* Remove client convenience wrappers */
#undef max_allowed_packet
#undef net_buffer_length

#ifdef EMBEDDED_LIBRARY

#undef MYSQL_SERVER

#ifndef MYSQL_CLIENT
#define MYSQL_CLIENT
#endif

#define CLI_MYSQL_REAL_CONNECT STDCALL cli_mysql_real_connect

#undef net_flush
my_bool	net_flush(NET *net);

#else  /*EMBEDDED_LIBRARY*/
#define CLI_MYSQL_REAL_CONNECT STDCALL mysql_real_connect
#endif /*EMBEDDED_LIBRARY*/
#include <my_sys.h>
#include <mysys_err.h>
#include <m_string.h>
#include <m_ctype.h>
#include "mysql_version.h"
#include "mysqld_error.h"
#include "errmsg.h"
#include <violite.h>
#if defined(THREAD) && !defined(__WIN__)
#include <my_pthread.h>				/* because of signal()	*/
#endif /* defined(THREAD) && !defined(__WIN__) */

#include <sys/stat.h>
#include <signal.h>
#include <time.h>
#ifdef	 HAVE_PWD_H
#include <pwd.h>
#endif
#if !defined(MSDOS) && !defined(__WIN__)
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#ifdef HAVE_SELECT_H
#  include <select.h>
#endif
#ifdef HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif
#endif /*!defined(MSDOS) && !defined(__WIN__) */
#ifdef HAVE_SYS_UN_H
#  include <sys/un.h>
#endif

#if defined(MSDOS) || defined(__WIN__)
#define perror(A)
#else
#include <errno.h>
#define SOCKET_ERROR -1
#endif

#ifdef __WIN__
#define CONNECT_TIMEOUT 20
#else
#define CONNECT_TIMEOUT 0
#endif

#include "client_settings.h"
#include <sql_common.h>

uint		mysql_port=0;
char		*mysql_unix_port= 0;
const char	*unknown_sqlstate= "HY000";
const char	*not_error_sqlstate= "00000";
const char	*cant_connect_sqlstate= "08001";
#ifdef HAVE_SMEM
char		 *shared_memory_base_name= 0;
const char 	*def_shared_memory_base_name= default_shared_memory_base_name;
#endif

static void mysql_close_free_options(MYSQL *mysql);
static void mysql_close_free(MYSQL *mysql);

#if !(defined(__WIN__) || defined(__NETWARE__))
static int wait_for_data(my_socket fd, uint timeout);
#endif

CHARSET_INFO *default_client_charset_info = &my_charset_latin1;

/* Server error code and message */
unsigned int mysql_server_last_errno;
char mysql_server_last_error[MYSQL_ERRMSG_SIZE];

/****************************************************************************
  A modified version of connect().  my_connect() allows you to specify
  a timeout value, in seconds, that we should wait until we
  derermine we can't connect to a particular host.  If timeout is 0,
  my_connect() will behave exactly like connect().

  Base version coded by Steve Bernacki, Jr. <steve@navinet.net>
*****************************************************************************/

int my_connect(my_socket fd, const struct sockaddr *name, uint namelen,
	       uint timeout)
{
#if defined(__WIN__) || defined(__NETWARE__)
  return connect(fd, (struct sockaddr*) name, namelen);
#else
  int flags, res, s_err;

  /*
    If they passed us a timeout of zero, we should behave
    exactly like the normal connect() call does.
  */

  if (timeout == 0)
    return connect(fd, (struct sockaddr*) name, namelen);

  flags = fcntl(fd, F_GETFL, 0);	  /* Set socket to not block */
#ifdef O_NONBLOCK
  fcntl(fd, F_SETFL, flags | O_NONBLOCK);  /* and save the flags..  */
#endif

  res= connect(fd, (struct sockaddr*) name, namelen);
  s_err= errno;			/* Save the error... */
  fcntl(fd, F_SETFL, flags);
  if ((res != 0) && (s_err != EINPROGRESS))
  {
    errno= s_err;			/* Restore it */
    return(-1);
  }
  if (res == 0)				/* Connected quickly! */
    return(0);
  return wait_for_data(fd, timeout);
#endif
}


/*
  Wait up to timeout seconds for a connection to be established.

  We prefer to do this with poll() as there is no limitations with this.
  If not, we will use select()
*/

#if !(defined(__WIN__) || defined(__NETWARE__))

static int wait_for_data(my_socket fd, uint timeout)
{
#ifdef HAVE_POLL
  struct pollfd ufds;
  int res;

  ufds.fd= fd;
  ufds.events= POLLIN | POLLPRI;
  if (!(res= poll(&ufds, 1, (int) timeout*1000)))
  {
    errno= EINTR;
    return -1;
  }
  if (res < 0 || !(ufds.revents & (POLLIN | POLLPRI)))
    return -1;
  return 0;
#else
  SOCKOPT_OPTLEN_TYPE s_err_size = sizeof(uint);
  fd_set sfds;
  struct timeval tv;
  time_t start_time, now_time;
  int res, s_err;

  if (fd >= FD_SETSIZE)				/* Check if wrong error */
    return 0;					/* Can't use timeout */

  /*
    Our connection is "in progress."  We can use the select() call to wait
    up to a specified period of time for the connection to suceed.
    If select() returns 0 (after waiting howevermany seconds), our socket
    never became writable (host is probably unreachable.)  Otherwise, if
    select() returns 1, then one of two conditions exist:
   
    1. An error occured.  We use getsockopt() to check for this.
    2. The connection was set up sucessfully: getsockopt() will
    return 0 as an error.
   
    Thanks goes to Andrew Gierth <andrew@erlenstar.demon.co.uk>
    who posted this method of timing out a connect() in
    comp.unix.programmer on August 15th, 1997.
  */

  FD_ZERO(&sfds);
  FD_SET(fd, &sfds);
  /*
    select could be interrupted by a signal, and if it is, 
    the timeout should be adjusted and the select restarted
    to work around OSes that don't restart select and 
    implementations of select that don't adjust tv upon
    failure to reflect the time remaining
   */
  start_time= my_time(0);
  for (;;)
  {
    tv.tv_sec = (long) timeout;
    tv.tv_usec = 0;
#if defined(HPUX10) && defined(THREAD)
    if ((res = select(fd+1, NULL, (int*) &sfds, NULL, &tv)) > 0)
      break;
#else
    if ((res = select(fd+1, NULL, &sfds, NULL, &tv)) > 0)
      break;
#endif
    if (res == 0)					/* timeout */
      return -1;
    now_time= my_time(0);
    timeout-= (uint) (now_time - start_time);
    if (errno != EINTR || (int) timeout <= 0)
      return -1;
  }

  /*
    select() returned something more interesting than zero, let's
    see if we have any errors.  If the next two statements pass,
    we've got an open socket!
  */

  s_err=0;
  if (getsockopt(fd, SOL_SOCKET, SO_ERROR, (char*) &s_err, &s_err_size) != 0)
    return(-1);

  if (s_err)
  {						/* getsockopt could succeed */
    errno = s_err;
    return(-1);					/* but return an error... */
  }
  return (0);					/* ok */
#endif /* HAVE_POLL */
}
#endif /* defined(__WIN__) || defined(__NETWARE__) */

/**
  Set the internal error message to mysql handler

  @param mysql    connection handle (client side)
  @param errcode  CR_ error code, passed to ER macro to get
                  error text
  @parma sqlstate SQL standard sqlstate
*/

void set_mysql_error(MYSQL *mysql, int errcode, const char *sqlstate)
{
  NET *net;
  DBUG_ENTER("set_mysql_error");
  DBUG_PRINT("enter", ("error :%d '%s'", errcode, ER(errcode)));
  DBUG_ASSERT(mysql != 0);

  if (mysql)
  {
    net= &mysql->net;
    net->last_errno= errcode;
    strmov(net->last_error, ER(errcode));
    strmov(net->sqlstate, sqlstate);
  }
  else
  {
    mysql_server_last_errno= errcode;
    strmov(mysql_server_last_error, ER(errcode));
  }
  DBUG_VOID_RETURN;
}

/**
  Clear possible error state of struct NET

  @param net  clear the state of the argument
*/

void net_clear_error(NET *net)
{
  net->last_errno= 0;
  net->last_error[0]= '\0';
  strmov(net->sqlstate, not_error_sqlstate);
}

/**
  Set an error message on the client.

  @param mysql     connection handle
  @param errcode   CR_* errcode, for client errors
  @param sqlstate  SQL standard sql state, unknown_sqlstate for the
                   majority of client errors.
  @param format    error message template, in sprintf format
  @param ...       variable number of arguments
*/

static void set_mysql_extended_error(MYSQL *mysql, int errcode,
                                     const char *sqlstate,
                                     const char *format, ...)
{
  NET *net;
  va_list args;
  DBUG_ENTER("set_mysql_extended_error");
  DBUG_PRINT("enter", ("error :%d '%s'", errcode, format));
  DBUG_ASSERT(mysql != 0);

  net= &mysql->net;
  net->last_errno= errcode;
  va_start(args, format);
  my_vsnprintf(net->last_error, sizeof(net->last_error)-1,
               format, args);
  va_end(args);
  strmov(net->sqlstate, sqlstate);

  DBUG_VOID_RETURN;
}



/*
  Create a named pipe connection
*/

#ifdef __WIN__

HANDLE create_named_pipe(MYSQL *mysql, uint connect_timeout, char **arg_host,
			 char **arg_unix_socket)
{
  HANDLE hPipe=INVALID_HANDLE_VALUE;
  char pipe_name[1024];
  DWORD dwMode;
  int i;
  my_bool testing_named_pipes=0;
  char *host= *arg_host, *unix_socket= *arg_unix_socket;

  if ( ! unix_socket || (unix_socket)[0] == 0x00)
    unix_socket = mysql_unix_port;
  if (!host || !strcmp(host,LOCAL_HOST))
    host=LOCAL_HOST_NAMEDPIPE;

  
  pipe_name[sizeof(pipe_name)-1]= 0;		/* Safety if too long string */
  strxnmov(pipe_name, sizeof(pipe_name)-1, "\\\\", host, "\\pipe\\",
	   unix_socket, NullS);
  DBUG_PRINT("info",("Server name: '%s'.  Named Pipe: %s", host, unix_socket));

  for (i=0 ; i < 100 ; i++)			/* Don't retry forever */
  {
    if ((hPipe = CreateFile(pipe_name,
			    GENERIC_READ | GENERIC_WRITE,
			    0,
			    NULL,
			    OPEN_EXISTING,
			    0,
			    NULL )) != INVALID_HANDLE_VALUE)
      break;
    if (GetLastError() != ERROR_PIPE_BUSY)
    {
      set_mysql_extended_error(mysql, CR_NAMEDPIPEOPEN_ERROR,
                               unknown_sqlstate, ER(CR_NAMEDPIPEOPEN_ERROR),
                               host, unix_socket, (ulong) GetLastError());
      return INVALID_HANDLE_VALUE;
    }
    /* wait for for an other instance */
    if (! WaitNamedPipe(pipe_name, connect_timeout*1000) )
    {
      set_mysql_extended_error(mysql, CR_NAMEDPIPEWAIT_ERROR, unknown_sqlstate,
                               ER(CR_NAMEDPIPEWAIT_ERROR),
                               host, unix_socket, (ulong) GetLastError());
      return INVALID_HANDLE_VALUE;
    }
  }
  if (hPipe == INVALID_HANDLE_VALUE)
  {
    set_mysql_extended_error(mysql, CR_NAMEDPIPEOPEN_ERROR, unknown_sqlstate,
                             ER(CR_NAMEDPIPEOPEN_ERROR), host, unix_socket,
                             (ulong) GetLastError());
    return INVALID_HANDLE_VALUE;
  }
  dwMode = PIPE_READMODE_BYTE | PIPE_WAIT;
  if ( !SetNamedPipeHandleState(hPipe, &dwMode, NULL, NULL) )
  {
    CloseHandle( hPipe );
    set_mysql_extended_error(mysql, CR_NAMEDPIPESETSTATE_ERROR,
                             unknown_sqlstate, ER(CR_NAMEDPIPESETSTATE_ERROR),
                             host, unix_socket, (ulong) GetLastError());
    return INVALID_HANDLE_VALUE;
  }
  *arg_host=host ; *arg_unix_socket=unix_socket;	/* connect arg */
  return (hPipe);
}
#endif


/*
  Create new shared memory connection, return handler of connection

  SYNOPSIS
    create_shared_memory()
    mysql		Pointer of mysql structure
    net			Pointer of net structure
    connect_timeout	Timeout of connection
*/

#ifdef HAVE_SMEM
HANDLE create_shared_memory(MYSQL *mysql,NET *net, uint connect_timeout)
{
  ulong smem_buffer_length = shared_memory_buffer_length + 4;
  /*
    event_connect_request is event object for start connection actions
    event_connect_answer is event object for confirm, that server put data
    handle_connect_file_map is file-mapping object, use for create shared
    memory
    handle_connect_map is pointer on shared memory
    handle_map is pointer on shared memory for client
    event_server_wrote,
    event_server_read,
    event_client_wrote,
    event_client_read are events for transfer data between server and client
    handle_file_map is file-mapping object, use for create shared memory
  */
  HANDLE event_connect_request = NULL;
  HANDLE event_connect_answer = NULL;
  HANDLE handle_connect_file_map = NULL;
  char *handle_connect_map = NULL;

  char *handle_map = NULL;
  HANDLE event_server_wrote = NULL;
  HANDLE event_server_read = NULL;
  HANDLE event_client_wrote = NULL;
  HANDLE event_client_read = NULL;
  HANDLE event_conn_closed = NULL;
  HANDLE handle_file_map = NULL;
  ulong connect_number;
  char connect_number_char[22], *p;
  char *tmp= NULL;
  char *suffix_pos;
  DWORD error_allow = 0;
  DWORD error_code = 0;
  DWORD event_access_rights= SYNCHRONIZE | EVENT_MODIFY_STATE;
  char *shared_memory_base_name = mysql->options.shared_memory_base_name;

  /*
     get enough space base-name + '_' + longest suffix we might ever send
   */
  if (!(tmp= (char *)my_malloc(strlen(shared_memory_base_name) + 32L, MYF(MY_FAE))))
    goto err;

  /*
    The name of event and file-mapping events create agree next rule:
    shared_memory_base_name+unique_part
    Where:
    shared_memory_base_name is unique value for each server
    unique_part is uniquel value for each object (events and file-mapping)
  */
  suffix_pos = strxmov(tmp, "Global\\", shared_memory_base_name, "_", NullS);
  strmov(suffix_pos, "CONNECT_REQUEST");
  if (!(event_connect_request= OpenEvent(event_access_rights, FALSE, tmp)))
  {
    error_allow = CR_SHARED_MEMORY_CONNECT_REQUEST_ERROR;
    goto err;
  }
  strmov(suffix_pos, "CONNECT_ANSWER");
  if (!(event_connect_answer= OpenEvent(event_access_rights,FALSE,tmp)))
  {
    error_allow = CR_SHARED_MEMORY_CONNECT_ANSWER_ERROR;
    goto err;
  }
  strmov(suffix_pos, "CONNECT_DATA");
  if (!(handle_connect_file_map= OpenFileMapping(FILE_MAP_WRITE,FALSE,tmp)))
  {
    error_allow = CR_SHARED_MEMORY_CONNECT_FILE_MAP_ERROR;
    goto err;
  }
  if (!(handle_connect_map= MapViewOfFile(handle_connect_file_map,
					  FILE_MAP_WRITE,0,0,sizeof(DWORD))))
  {
    error_allow = CR_SHARED_MEMORY_CONNECT_MAP_ERROR;
    goto err;
  }

  /* Send to server request of connection */
  if (!SetEvent(event_connect_request))
  {
    error_allow = CR_SHARED_MEMORY_CONNECT_SET_ERROR;
    goto err;
  }

  /* Wait of answer from server */
  if (WaitForSingleObject(event_connect_answer,connect_timeout*1000) !=
      WAIT_OBJECT_0)
  {
    error_allow = CR_SHARED_MEMORY_CONNECT_ABANDONED_ERROR;
    goto err;
  }

  /* Get number of connection */
  connect_number = uint4korr(handle_connect_map);/*WAX2*/
  p= int10_to_str(connect_number, connect_number_char, 10);

  /*
    The name of event and file-mapping events create agree next rule:
    shared_memory_base_name+unique_part+number_of_connection

    Where:
    shared_memory_base_name is uniquel value for each server
    unique_part is uniquel value for each object (events and file-mapping)
    number_of_connection is number of connection between server and client
  */
  suffix_pos = strxmov(tmp, "Global\\", shared_memory_base_name, "_", connect_number_char,
		       "_", NullS);
  strmov(suffix_pos, "DATA");
  if ((handle_file_map = OpenFileMapping(FILE_MAP_WRITE,FALSE,tmp)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_FILE_MAP_ERROR;
    goto err2;
  }
  if ((handle_map = MapViewOfFile(handle_file_map,FILE_MAP_WRITE,0,0,
				  smem_buffer_length)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_MAP_ERROR;
    goto err2;
  }

  strmov(suffix_pos, "SERVER_WROTE");
  if ((event_server_wrote = OpenEvent(event_access_rights,FALSE,tmp)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_EVENT_ERROR;
    goto err2;
  }

  strmov(suffix_pos, "SERVER_READ");
  if ((event_server_read = OpenEvent(event_access_rights,FALSE,tmp)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_EVENT_ERROR;
    goto err2;
  }

  strmov(suffix_pos, "CLIENT_WROTE");
  if ((event_client_wrote = OpenEvent(event_access_rights,FALSE,tmp)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_EVENT_ERROR;
    goto err2;
  }

  strmov(suffix_pos, "CLIENT_READ");
  if ((event_client_read = OpenEvent(event_access_rights,FALSE,tmp)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_EVENT_ERROR;
    goto err2;
  }

  strmov(suffix_pos, "CONNECTION_CLOSED");
  if ((event_conn_closed = OpenEvent(event_access_rights,FALSE,tmp)) == NULL)
  {
    error_allow = CR_SHARED_MEMORY_EVENT_ERROR;
    goto err2;
  }
  /*
    Set event that server should send data
  */
  SetEvent(event_server_read);

err2:
  if (error_allow == 0)
  {
    net->vio= vio_new_win32shared_memory(net,handle_file_map,handle_map,
                                         event_server_wrote,
                                         event_server_read,event_client_wrote,
                                         event_client_read,event_conn_closed);
  }
  else
  {
    error_code = GetLastError();
    if (event_server_read)
      CloseHandle(event_server_read);
    if (event_server_wrote)
      CloseHandle(event_server_wrote);
    if (event_client_read)
      CloseHandle(event_client_read);
    if (event_client_wrote)
      CloseHandle(event_client_wrote);
    if (event_conn_closed)
      CloseHandle(event_conn_closed);
    if (handle_map)
      UnmapViewOfFile(handle_map);
    if (handle_file_map)
      CloseHandle(handle_file_map);
  }
err:
  if (tmp)
    my_free(tmp, MYF(0));
  if (error_allow)
    error_code = GetLastError();
  if (event_connect_request)
    CloseHandle(event_connect_request);
  if (event_connect_answer)
    CloseHandle(event_connect_answer);
  if (handle_connect_map)
    UnmapViewOfFile(handle_connect_map);
  if (handle_connect_file_map)
    CloseHandle(handle_connect_file_map);
  if (error_allow)
  {
    if (error_allow == CR_SHARED_MEMORY_EVENT_ERROR)
      set_mysql_extended_error(mysql, error_allow, unknown_sqlstate,
                               ER(error_allow), suffix_pos, error_code);
    else
      set_mysql_extended_error(mysql, error_allow, unknown_sqlstate,
                               ER(error_allow), error_code);
    return(INVALID_HANDLE_VALUE);
  }
  return(handle_map);
}
#endif

/*****************************************************************************
  Read a packet from server. Give error message if socket was down
  or packet is an error message
*****************************************************************************/

ulong
cli_safe_read(MYSQL *mysql)
{
  NET *net= &mysql->net;
  ulong len=0;
  init_sigpipe_variables

  /* Don't give sigpipe errors if the client doesn't want them */
  set_sigpipe(mysql);
  if (net->vio != 0)
    len=my_net_read(net);
  reset_sigpipe(mysql);

  if (len == packet_error || len == 0)
  {
    DBUG_PRINT("error",("Wrong connection or packet. fd: %s  len: %lu",
			vio_description(net->vio),len));
#ifdef MYSQL_SERVER
    if (net->vio && vio_was_interrupted(net->vio))
      return (packet_error);
#endif /*MYSQL_SERVER*/
    end_server(mysql);
    set_mysql_error(mysql, net->last_errno == ER_NET_PACKET_TOO_LARGE ?
                    CR_NET_PACKET_TOO_LARGE: CR_SERVER_LOST, unknown_sqlstate);
    return (packet_error);
  }
  if (net->read_pos[0] == 255)
  {
    if (len > 3)
    {
      char *pos=(char*) net->read_pos+1;
      net->last_errno=uint2korr(pos);
      pos+=2;
      len-=2;
      if (protocol_41(mysql) && pos[0] == '#')
      {
	strmake(net->sqlstate, pos+1, SQLSTATE_LENGTH);
	pos+= SQLSTATE_LENGTH+1;
      }
      else
      {
        /*
          The SQL state hasn't been received -- it should be reset to HY000
          (unknown error sql state).
        */

        strmov(net->sqlstate, unknown_sqlstate);
      }

      (void) strmake(net->last_error,(char*) pos,
		     min((uint) len,(uint) sizeof(net->last_error)-1));
    }
    else
      set_mysql_error(mysql, CR_UNKNOWN_ERROR, unknown_sqlstate);
    /*
      Cover a protocol design error: error packet does not
      contain the server status. Therefore, the client has no way
      to find out whether there are more result sets of
      a multiple-result-set statement pending. Luckily, in 5.0 an
      error always aborts execution of a statement, wherever it is
      a multi-statement or a stored procedure, so it should be
      safe to unconditionally turn off the flag here.
    */
    mysql->server_status&= ~SERVER_MORE_RESULTS_EXISTS;

    DBUG_PRINT("error",("Got error: %d/%s (%s)",
                        net->last_errno,
                        net->sqlstate,
                        net->last_error));
    return(packet_error);
  }
  return len;
}

void free_rows(MYSQL_DATA *cur)
{
  if (cur)
  {
    free_root(&cur->alloc,MYF(0));
    my_free((uchar*) cur,MYF(0));
  }
}

my_bool
cli_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)
{
  NET *net= &mysql->net;
  my_bool result= 1;
  init_sigpipe_variables
  my_bool stmt_skip= stmt ? stmt->state != MYSQL_STMT_INIT_DONE : FALSE;
  DBUG_ENTER("cli_advanced_command");

  /* Don't give sigpipe errors if the client doesn't want them */
  set_sigpipe(mysql);

  if (mysql->net.vio == 0)
  {						/* Do reconnect if possible */
    if (mysql_reconnect(mysql) || stmt_skip)
      DBUG_RETURN(1);
  }
  if (mysql->status != MYSQL_STATUS_READY ||
      mysql->server_status & SERVER_MORE_RESULTS_EXISTS)
  {
    DBUG_PRINT("error",("state: %d", mysql->status));
    set_mysql_error(mysql, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate);
    DBUG_RETURN(1);
  }

  net_clear_error(net);
  mysql->info=0;
  mysql->affected_rows= ~(my_ulonglong) 0;
  /*
    We don't want to clear the protocol buffer on COM_QUIT, because if
    the previous command was a shutdown command, we may have the
    response for the COM_QUIT already in the communication buffer
  */
  net_clear(&mysql->net, (command != COM_QUIT));

  if (net_write_command(net,(uchar) command, header, header_length,
			arg, arg_length))
  {
    DBUG_PRINT("error",("Can't send command to server. Error: %d",
			socket_errno));
    if (net->last_errno == ER_NET_PACKET_TOO_LARGE)
    {
      set_mysql_error(mysql, CR_NET_PACKET_TOO_LARGE, unknown_sqlstate);
      goto end;
    }
    end_server(mysql);
    if (mysql_reconnect(mysql) || stmt_skip)
      goto end;
    if (net_write_command(net,(uchar) command, header, header_length,
			  arg, arg_length))
    {
      set_mysql_error(mysql, CR_SERVER_GONE_ERROR, unknown_sqlstate);
      goto end;
    }
  }
  result=0;
  if (!skip_check)
    result= ((mysql->packet_length=cli_safe_read(mysql)) == packet_error ?
	     1 : 0);
end:
  reset_sigpipe(mysql);
  DBUG_PRINT("exit",("result: %d", result));
  DBUG_RETURN(result);
}

void free_old_query(MYSQL *mysql)
{
  DBUG_ENTER("free_old_query");
  if (mysql->fields)
    free_root(&mysql->field_alloc,MYF(0));
  init_alloc_root(&mysql->field_alloc,8192,0); /* Assume rowlength < 8192 */
  mysql->fields= 0;
  mysql->field_count= 0;			/* For API */
  mysql->warning_count= 0;
  mysql->info= 0;
  DBUG_VOID_RETURN;
}

/*
  Flush result set sent from server
*/

static void cli_flush_use_result(MYSQL *mysql)
{
  /* Clear the current execution status */
  DBUG_ENTER("cli_flush_use_result");
  DBUG_PRINT("warning",("Not all packets read, clearing them"));
  for (;;)
  {
    ulong pkt_len;
    if ((pkt_len=cli_safe_read(mysql)) == packet_error)
      break;
    if (pkt_len <= 8 && mysql->net.read_pos[0] == 254)
    {
      if (protocol_41(mysql))
      {
        char *pos= (char*) mysql->net.read_pos + 1;
        mysql->warning_count=uint2korr(pos); pos+=2;
        mysql->server_status=uint2korr(pos); pos+=2;
      }
      break;                            /* End of data */
    }
  }
  DBUG_VOID_RETURN;
}


#ifdef __WIN__
static my_bool is_NT(void)
{
  char *os=getenv("OS");
  return (os && !strcmp(os, "Windows_NT")) ? 1 : 0;
}
#endif


#ifdef CHECK_LICENSE
/**
  Check server side variable 'license'.

  If the variable does not exist or does not contain 'Commercial',
  we're talking to non-commercial server from commercial client.

  @retval  0   success
  @retval  !0  network error or the server is not commercial.
               Error code is saved in mysql->net.last_errno.
*/

static int check_license(MYSQL *mysql)
{
  MYSQL_ROW row;
  MYSQL_RES *res;
  NET *net= &mysql->net;
  static const char query[]= "SELECT @@license";
  static const char required_license[]= STRINGIFY_ARG(LICENSE);

  if (mysql_real_query(mysql, query, sizeof(query)-1))
  {
    if (net->last_errno == ER_UNKNOWN_SYSTEM_VARIABLE)
    {
      set_mysql_extended_error(mysql, CR_WRONG_LICENSE, unknown_sqlstate,
                               ER(CR_WRONG_LICENSE), required_license);
    }
    return 1;
  }
  if (!(res= mysql_use_result(mysql)))
    return 1;
  row= mysql_fetch_row(res);
  /* 
    If no rows in result set, or column value is NULL (none of these
    two is ever true for server variables now), or column value
    mismatch, set wrong license error.
  */
  if (!net->last_errno &&
      (!row || !row[0] ||
       strncmp(row[0], required_license, sizeof(required_license))))
  {
    set_mysql_extended_error(mysql, CR_WRONG_LICENSE, unknown_sqlstate,
                             ER(CR_WRONG_LICENSE), required_license);
  }
  mysql_free_result(res);
  return net->last_errno;
}
#endif /* CHECK_LICENSE */


/**************************************************************************
  Shut down connection
**************************************************************************/

void end_server(MYSQL *mysql)
{
  int save_errno= errno;
  DBUG_ENTER("end_server");
  if (mysql->net.vio != 0)
  {
    init_sigpipe_variables
    DBUG_PRINT("info",("Net: %s", vio_description(mysql->net.vio)));
    set_sigpipe(mysql);
    vio_delete(mysql->net.vio);
    reset_sigpipe(mysql);
    mysql->net.vio= 0;          /* Marker */
  }
  net_end(&mysql->net);
  free_old_query(mysql);
  errno= save_errno;
  DBUG_VOID_RETURN;
}


void STDCALL
mysql_free_result(MYSQL_RES *result)
{
  DBUG_ENTER("mysql_free_result");
  DBUG_PRINT("enter",("mysql_res: 0x%lx", (long) result));
  if (result)
  {
    MYSQL *mysql= result->handle;
    if (mysql)
    {
      if (mysql->unbuffered_fetch_owner == &result->unbuffered_fetch_cancelled)
        mysql->unbuffered_fetch_owner= 0;
      if (mysql->status == MYSQL_STATUS_USE_RESULT)
      {
        (*mysql->methods->flush_use_result)(mysql);
        mysql->status=MYSQL_STATUS_READY;
        if (mysql->unbuffered_fetch_owner)
          *mysql->unbuffered_fetch_owner= TRUE;
      }
    }
    free_rows(result->data);
    if (result->fields)
      free_root(&result->field_alloc,MYF(0));
    if (result->row)
      my_free((uchar*) result->row,MYF(0));
    my_free((uchar*) result,MYF(0));
  }
  DBUG_VOID_RETURN;
}

/****************************************************************************
  Get options from my.cnf
****************************************************************************/

static const char *default_options[]=
{
  "port","socket","compress","password","pipe", "timeout", "user",
  "init-command", "host", "database", "debug", "return-found-rows",
  "ssl-key" ,"ssl-cert" ,"ssl-ca" ,"ssl-capath",
  "character-sets-dir", "default-character-set", "interactive-timeout",
  "connect-timeout", "local-infile", "disable-local-infile",
  "ssl-cipher", "max-allowed-packet", "protocol", "shared-memory-base-name",
  "multi-results", "multi-statements", "multi-queries", "secure-auth",
  "report-data-truncation",
  NullS
};

static TYPELIB option_types={array_elements(default_options)-1,
			     "options",default_options, NULL};

const char *sql_protocol_names_lib[] =
{ "TCP", "SOCKET", "PIPE", "MEMORY", NullS };
TYPELIB sql_protocol_typelib = {array_elements(sql_protocol_names_lib)-1,"",
				sql_protocol_names_lib, NULL};

static int add_init_command(struct st_mysql_options *options, const char *cmd)
{
  char *tmp;

  if (!options->init_commands)
  {
    options->init_commands= (DYNAMIC_ARRAY*)my_malloc(sizeof(DYNAMIC_ARRAY),
						      MYF(MY_WME));
    init_dynamic_array(options->init_commands,sizeof(char*),0,5 CALLER_INFO);
  }

  if (!(tmp= my_strdup(cmd,MYF(MY_WME))) ||
      insert_dynamic(options->init_commands, (uchar*)&tmp))
  {
    my_free(tmp, MYF(MY_ALLOW_ZERO_PTR));
    return 1;
  }

  return 0;
}

void mysql_read_default_options(struct st_mysql_options *options,
				const char *filename,const char *group)
{
  int argc;
  char *argv_buff[1],**argv;
  const char *groups[3];
  DBUG_ENTER("mysql_read_default_options");
  DBUG_PRINT("enter",("file: %s  group: %s",filename,group ? group :"NULL"));

  argc=1; argv=argv_buff; argv_buff[0]= (char*) "client";
  groups[0]= (char*) "client"; groups[1]= (char*) group; groups[2]=0;

  load_defaults(filename, groups, &argc, &argv);
  if (argc != 1)				/* If some default option */
  {
    char **option=argv;
    while (*++option)
    {
      /* DBUG_PRINT("info",("option: %s",option[0])); */
      if (option[0][0] == '-' && option[0][1] == '-')
      {
	char *end=strcend(*option,'=');
	char *opt_arg=0;
	if (*end)
	{
	  opt_arg=end+1;
	  *end=0;				/* Remove '=' */
	}
	/* Change all '_' in variable name to '-' */
	for (end= *option ; *(end= strcend(end,'_')) ; )
	  *end= '-';
	switch (find_type(*option+2,&option_types,2)) {
	case 1:				/* port */
	  if (opt_arg)
	    options->port=atoi(opt_arg);
	  break;
	case 2:				/* socket */
	  if (opt_arg)
	  {
	    my_free(options->unix_socket,MYF(MY_ALLOW_ZERO_PTR));
	    options->unix_socket=my_strdup(opt_arg,MYF(MY_WME));
	  }
	  break;
	case 3:				/* compress */
	  options->compress=1;
	  options->client_flag|= CLIENT_COMPRESS;
	  break;
	case 4:				/* password */
	  if (opt_arg)
	  {
	    my_free(options->password,MYF(MY_ALLOW_ZERO_PTR));
	    options->password=my_strdup(opt_arg,MYF(MY_WME));
	  }
	  break;
        case 5:
          options->protocol = MYSQL_PROTOCOL_PIPE;
	case 20:			/* connect_timeout */
	case 6:				/* timeout */
	  if (opt_arg)
	    options->connect_timeout=atoi(opt_arg);
	  break;
	case 7:				/* user */
	  if (opt_arg)
	  {
	    my_free(options->user,MYF(MY_ALLOW_ZERO_PTR));
	    options->user=my_strdup(opt_arg,MYF(MY_WME));
	  }
	  break;
	case 8:				/* init-command */
	  add_init_command(options,opt_arg);
	  break;
	case 9:				/* host */
	  if (opt_arg)
	  {
	    my_free(options->host,MYF(MY_ALLOW_ZERO_PTR));
	    options->host=my_strdup(opt_arg,MYF(MY_WME));
	  }
	  break;
	case 10:			/* database */
	  if (opt_arg)
	  {
	    my_free(options->db,MYF(MY_ALLOW_ZERO_PTR));
	    options->db=my_strdup(opt_arg,MYF(MY_WME));
	  }
	  break;
	case 11:			/* debug */
#ifdef MYSQL_CLIENT
	  mysql_debug(opt_arg ? opt_arg : "d:t:o,/tmp/client.trace");
	  break;
#endif
	case 12:			/* return-found-rows */
	  options->client_flag|=CLIENT_FOUND_ROWS;
	  break;
	case 13:				/* Ignore SSL options */
	case 14:
	case 15:
	case 16:
        case 23:
	  break;
	case 17:			/* charset-lib */
	  my_free(options->charset_dir,MYF(MY_ALLOW_ZERO_PTR));
          options->charset_dir = my_strdup(opt_arg, MYF(MY_WME));
	  break;
	case 18:
	  my_free(options->charset_name,MYF(MY_ALLOW_ZERO_PTR));
          options->charset_name = my_strdup(opt_arg, MYF(MY_WME));
	  break;
	case 19:				/* Interactive-timeout */
	  options->client_flag|= CLIENT_INTERACTIVE;
	  break;
	case 21:
	  if (!opt_arg || atoi(opt_arg) != 0)
	    options->client_flag|= CLIENT_LOCAL_FILES;
	  else
	    options->client_flag&= ~CLIENT_LOCAL_FILES;
	  break;
	case 22:
	  options->client_flag&= ~CLIENT_LOCAL_FILES;
          break;
	case 24: /* max-allowed-packet */
          if (opt_arg)
	    options->max_allowed_packet= atoi(opt_arg);
	  break;
        case 25: /* protocol */
          if ((options->protocol= find_type(opt_arg,
					    &sql_protocol_typelib,0)) <= 0)
          {
            fprintf(stderr, "Unknown option to protocol: %s\n", opt_arg);
            exit(1);
          }
          break;
        case 26: /* shared_memory_base_name */
#ifdef HAVE_SMEM
          if (options->shared_memory_base_name != def_shared_memory_base_name)
            my_free(options->shared_memory_base_name,MYF(MY_ALLOW_ZERO_PTR));
          options->shared_memory_base_name=my_strdup(opt_arg,MYF(MY_WME));
#endif
          break;
	case 27: /* multi-results */
	  options->client_flag|= CLIENT_MULTI_RESULTS;
	  break;
	case 28: /* multi-statements */
	case 29: /* multi-queries */
	  options->client_flag|= CLIENT_MULTI_STATEMENTS | CLIENT_MULTI_RESULTS;
	  break;
        case 30: /* secure-auth */
          options->secure_auth= TRUE;
          break;
        case 31: /* report-data-truncation */
          options->report_data_truncation= opt_arg ? test(atoi(opt_arg)) : 1;
          break;
	default:
	  DBUG_PRINT("warning",("unknown option: %s",option[0]));
	}
      }
    }
  }
  free_defaults(argv);
  DBUG_VOID_RETURN;
}


/**************************************************************************
  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 cli_fetch_lengths(ulong *to, MYSQL_ROW column,
			      unsigned int field_count)
{ 
  ulong *prev_length;
  char *start=0;
  MYSQL_ROW end;

  prev_length=0;				/* Keep gcc happy */
  for (end=column + field_count + 1 ; column != end ; column++, to++)
  {
    if (!*column)
    {
      *to= 0;					/* Null */
      continue;
    }
    if (start)					/* Found end of prev string */
      *prev_length= (ulong) (*column-start-1);
    start= *column;
    prev_length= to;
  }
}

/***************************************************************************
  Change field rows to field structs
***************************************************************************/

MYSQL_FIELD *
unpack_fields(MYSQL_DATA *data,MEM_ROOT *alloc,uint fields,
	      my_bool default_value, uint server_capabilities)
{
  MYSQL_ROWS	*row;
  MYSQL_FIELD	*field,*result;
  ulong lengths[9];				/* Max of fields */
  DBUG_ENTER("unpack_fields");

  field= result= (MYSQL_FIELD*) alloc_root(alloc,
					   (uint) sizeof(*field)*fields);
  if (!result)
  {
    free_rows(data);				/* Free old data */
    DBUG_RETURN(0);
  }
  bzero((char*) field, (uint) sizeof(MYSQL_FIELD)*fields);
  if (server_capabilities & CLIENT_PROTOCOL_41)
  {
    /* server is 4.1, and returns the new field result format */
    for (row=data->data; row ; row = row->next,field++)
    {
      uchar *pos;
      /* fields count may be wrong */
      DBUG_ASSERT((uint) (field - result) < fields);
      cli_fetch_lengths(&lengths[0], row->data, default_value ? 8 : 7);
      field->catalog=   strmake_root(alloc,(char*) row->data[0], lengths[0]);
      field->db=        strmake_root(alloc,(char*) row->data[1], lengths[1]);
      field->table=     strmake_root(alloc,(char*) row->data[2], lengths[2]);
      field->org_table= strmake_root(alloc,(char*) row->data[3], lengths[3]);
      field->name=      strmake_root(alloc,(char*) row->data[4], lengths[4]);
      field->org_name=  strmake_root(alloc,(char*) row->data[5], lengths[5]);

      field->catalog_length=	lengths[0];
      field->db_length=		lengths[1];
      field->table_length=	lengths[2];
      field->org_table_length=	lengths[3];
      field->name_length=	lengths[4];
      field->org_name_length=	lengths[5];

      /* Unpack fixed length parts */
      pos= (uchar*) row->data[6];
      field->charsetnr= uint2korr(pos);
      field->length=	(uint) uint4korr(pos+2);
      field->type=	(enum enum_field_types) pos[6];
      field->flags=	uint2korr(pos+7);
      field->decimals=  (uint) pos[9];

      if (INTERNAL_NUM_FIELD(field))
        field->flags|= NUM_FLAG;
      if (default_value && row->data[7])
      {
        field->def=strmake_root(alloc,(char*) row->data[7], lengths[7]);
	field->def_length= lengths[7];
      }
      else
        field->def=0;
      field->max_length= 0;
    }
  }
#ifndef DELETE_SUPPORT_OF_4_0_PROTOCOL
  else
  {
    /* old protocol, for backward compatibility */
    for (row=data->data; row ; row = row->next,field++)
    {
      cli_fetch_lengths(&lengths[0], row->data, default_value ? 6 : 5);
      field->org_table= field->table=  strdup_root(alloc,(char*) row->data[0]);
      field->name=   strdup_root(alloc,(char*) row->data[1]);
      field->length= (uint) uint3korr(row->data[2]);
      field->type=   (enum enum_field_types) (uchar) row->data[3][0];

      field->catalog=(char*)  "";
      field->db=     (char*)  "";
      field->catalog_length= 0;
      field->db_length= 0;
      field->org_table_length=	field->table_length=	lengths[0];
      field->name_length=	lengths[1];

      if (server_capabilities & CLIENT_LONG_FLAG)
      {
        field->flags=   uint2korr(row->data[4]);
        field->decimals=(uint) (uchar) row->data[4][2];
      }
      else
      {
        field->flags=   (uint) (uchar) row->data[4][0];
        field->decimals=(uint) (uchar) row->data[4][1];
      }
      if (INTERNAL_NUM_FIELD(field))
        field->flags|= NUM_FLAG;
      if (default_value && row->data[5])
      {
        field->def=strdup_root(alloc,(char*) row->data[5]);
	field->def_length= lengths[5];
      }
      else
        field->def=0;
      field->max_length= 0;
    }
  }
#endif /* DELETE_SUPPORT_OF_4_0_PROTOCOL */
  free_rows(data);				/* Free old data */
  DBUG_RETURN(result);
}

/* Read all rows (fields or data) from server */

MYSQL_DATA *cli_read_rows(MYSQL *mysql,MYSQL_FIELD *mysql_fields,
			  unsigned int fields)
{
  uint	field;
  ulong pkt_len;
  ulong len;
  uchar *cp;
  char	*to, *end_to;
  MYSQL_DATA *result;
  MYSQL_ROWS **prev_ptr,*cur;
  NET *net = &mysql->net;
  DBUG_ENTER("cli_read_rows");

  if ((pkt_len= cli_safe_read(mysql)) == packet_error)
    DBUG_RETURN(0);
  if (!(result=(MYSQL_DATA*) my_malloc(sizeof(MYSQL_DATA),
				       MYF(MY_WME | MY_ZEROFILL))))
  {
    set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
    DBUG_RETURN(0);
  }
  init_alloc_root(&result->alloc,8192,0);	/* Assume rowlength < 8192 */
  result->alloc.min_malloc=sizeof(MYSQL_ROWS);
  prev_ptr= &result->data;
  result->rows=0;
  result->fields=fields;

  /*
    The last EOF packet is either a single 254 character or (in MySQL 4.1)
    254 followed by 1-7 status bytes.

    This doesn't conflict with normal usage of 254 which stands for a
    string where the length of the string is 8 bytes. (see net_field_length())
  */

  while (*(cp=net->read_pos) != 254 || pkt_len >= 8)
  {
    result->rows++;
    if (!(cur= (MYSQL_ROWS*) alloc_root(&result->alloc,
					sizeof(MYSQL_ROWS))) ||
	!(cur->data= ((MYSQL_ROW)
		      alloc_root(&result->alloc,
				 (fields+1)*sizeof(char *)+pkt_len))))
    {
      free_rows(result);
      set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
      DBUG_RETURN(0);
    }
    *prev_ptr=cur;
    prev_ptr= &cur->next;
    to= (char*) (cur->data+fields+1);
    end_to=to+pkt_len-1;
    for (field=0 ; field < fields ; field++)
    {
      if ((len=(ulong) net_field_length(&cp)) == NULL_LENGTH)
      {						/* null field */
	cur->data[field] = 0;
      }
      else
      {
	cur->data[field] = to;
        if (len > (ulong) (end_to - to))
        {
          free_rows(result);
          set_mysql_error(mysql, CR_MALFORMED_PACKET, unknown_sqlstate);
          DBUG_RETURN(0);
        }
	memcpy(to,(char*) cp,len); to[len]=0;
	to+=len+1;
	cp+=len;
	if (mysql_fields)
	{
	  if (mysql_fields[field].max_length < len)
	    mysql_fields[field].max_length=len;
	}
      }
    }
    cur->data[field]=to;			/* End of last field */
    if ((pkt_len=cli_safe_read(mysql)) == packet_error)
    {
      free_rows(result);
      DBUG_RETURN(0);
    }
  }
  *prev_ptr=0;					/* last pointer is null */
  if (pkt_len > 1)				/* MySQL 4.1 protocol */
  {
    mysql->warning_count= uint2korr(cp+1);
    mysql->server_status= uint2korr(cp+3);
    DBUG_PRINT("info",("status: %u  warning_count:  %u",
		       mysql->server_status, mysql->warning_count));
  }
  DBUG_PRINT("exit", ("Got %lu rows", (ulong) result->rows));
  DBUG_RETURN(result);
}

/*
  Read one row. Uses packet buffer as storage for fields.
  When next packet is read, the previous field values are destroyed
*/


static int
read_one_row(MYSQL *mysql,uint fields,MYSQL_ROW row, ulong *lengths)
{
  uint field;
  ulong pkt_len,len;
  uchar *pos, *prev_pos, *end_pos;
  NET *net= &mysql->net;

  if ((pkt_len=cli_safe_read(mysql)) == packet_error)
    return -1;
  if (pkt_len <= 8 && net->read_pos[0] == 254)
  {
    if (pkt_len > 1)				/* MySQL 4.1 protocol */
    {
      mysql->warning_count= uint2korr(net->read_pos+1);
      mysql->server_status= uint2korr(net->read_pos+3);
    }
    return 1;				/* End of data */
  }
  prev_pos= 0;				/* allowed to write at packet[-1] */
  pos=net->read_pos;
  end_pos=pos+pkt_len;
  for (field=0 ; field < fields ; field++)
  {
    if ((len=(ulong) net_field_length(&pos)) == NULL_LENGTH)
    {						/* null field */
      row[field] = 0;
      *lengths++=0;
    }
    else
    {
      if (len > (ulong) (end_pos - pos))
      {
        set_mysql_error(mysql, CR_UNKNOWN_ERROR, unknown_sqlstate);
        return -1;
      }
      row[field] = (char*) pos;
      pos+=len;
      *lengths++=len;
    }
    if (prev_pos)
      *prev_pos=0;				/* Terminate prev field */
    prev_pos=pos;
  }
  row[field]=(char*) prev_pos+1;		/* End of last field */
  *prev_pos=0;					/* Terminate last field */
  return 0;
}


/****************************************************************************
  Init MySQL structure or allocate one
****************************************************************************/

MYSQL * STDCALL
mysql_init(MYSQL *mysql)
{
  if (mysql_server_init(0, NULL, NULL))
    return 0;
  if (!mysql)
  {
    if (!(mysql=(MYSQL*) my_malloc(sizeof(*mysql),MYF(MY_WME | MY_ZEROFILL))))
    {
      set_mysql_error(NULL, CR_OUT_OF_MEMORY, unknown_sqlstate);
      return 0;
    }
    mysql->free_me=1;
  }
  else
    bzero((char*) (mysql), sizeof(*(mysql)));
  mysql->options.connect_timeout= CONNECT_TIMEOUT;
  mysql->charset=default_client_charset_info;
  strmov(mysql->net.sqlstate, not_error_sqlstate);

  /*
    Only enable LOAD DATA INFILE by default if configured with
    --enable-local-infile
  */

#if defined(ENABLED_LOCAL_INFILE) && !defined(MYSQL_SERVER)
  mysql->options.client_flag|= CLIENT_LOCAL_FILES;
#endif

#ifdef HAVE_SMEM
  mysql->options.shared_memory_base_name= (char*) def_shared_memory_base_name;
#endif

  mysql->options.methods_to_use= MYSQL_OPT_GUESS_CONNECTION;
  mysql->options.report_data_truncation= TRUE;  /* default */

  /*
    By default we don't reconnect because it could silently corrupt data (after
    reconnection you potentially lose table locks, user variables, session
    variables (transactions but they are specifically dealt with in
    mysql_reconnect()).
    This is a change: < 5.0.3 mysql->reconnect was set to 1 by default.
    How this change impacts existing apps:
    - existing apps which relyed on the default will see a behaviour change;
    they will have to set reconnect=1 after mysql_real_connect().
    - existing apps which explicitely asked for reconnection (the only way they
    could do it was by setting mysql.reconnect to 1 after mysql_real_connect())
    will not see a behaviour change.
    - existing apps which explicitely asked for no reconnection
    (mysql.reconnect=0) will not see a behaviour change.
  */
  mysql->reconnect= 0;

  return mysql;
}


/*
  Fill in SSL part of MYSQL structure and set 'use_ssl' flag.
  NB! Errors are not reported until you do mysql_real_connect.
*/

#define strdup_if_not_null(A) (A) == 0 ? 0 : my_strdup((A),MYF(MY_WME))

my_bool STDCALL
mysql_ssl_set(MYSQL *mysql __attribute__((unused)) ,
	      const char *key __attribute__((unused)),
	      const char *cert __attribute__((unused)),
	      const char *ca __attribute__((unused)),
	      const char *capath __attribute__((unused)),
	      const char *cipher __attribute__((unused)))
{
  DBUG_ENTER("mysql_ssl_set");
  DBUG_RETURN(0);
}


/*
  Free strings in the SSL structure and clear 'use_ssl' flag.
  NB! Errors are not reported until you do mysql_real_connect.
*/

/*
  Return the SSL cipher (if any) used for current
  connection to the server.

  SYNOPSYS
    mysql_get_ssl_cipher()
      mysql pointer to the mysql connection

*/

const char * STDCALL
mysql_get_ssl_cipher(MYSQL *mysql __attribute__((unused)))
{
  DBUG_ENTER("mysql_get_ssl_cipher");
  DBUG_RETURN(NULL);
}


/*
  Check the server's (subject) Common Name against the
  hostname we connected to

  SYNOPSIS
  ssl_verify_server_cert()
    vio              pointer to a SSL connected vio
    server_hostname  name of the server that we connected to

  RETURN VALUES
   0 Success
   1 Failed to validate server

 */


/*
  Note that the mysql argument must be initialized with mysql_init()
  before calling mysql_real_connect !
*/

static my_bool cli_read_query_result(MYSQL *mysql);
static MYSQL_RES *cli_use_result(MYSQL *mysql);

static MYSQL_METHODS client_methods=
{
  cli_read_query_result,                       /* read_query_result */
  cli_advanced_command,                        /* advanced_command */
  cli_read_rows,                               /* read_rows */
  cli_use_result,                              /* use_result */
  cli_fetch_lengths,                           /* fetch_lengths */
  cli_flush_use_result,                         /* flush_use_result */
#ifndef MYSQL_SERVER
  cli_list_fields,                            /* list_fields */
  cli_unbuffered_fetch,                        /* unbuffered_fetch */
  cli_read_statistics,                         /* read_statistics */
  cli_read_query_result,                       /* next_result */
  cli_read_change_user_result,                 /* read_change_user_result */
#endif
};

C_MODE_START
int mysql_init_character_set(MYSQL *mysql)
{
  const char *default_collation_name;
  
  /* Set character set */
  if (!mysql->options.charset_name)
  {
    default_collation_name= MYSQL_DEFAULT_COLLATION_NAME;
    if (!(mysql->options.charset_name= 
       my_strdup(MYSQL_DEFAULT_CHARSET_NAME,MYF(MY_WME))))
    return 1;
  }
  else
    default_collation_name= NULL;
  
  {
    const char *save= charsets_dir;
    if (mysql->options.charset_dir)
      charsets_dir=mysql->options.charset_dir;
    mysql->charset=get_charset_by_csname(mysql->options.charset_name,
                                         MY_CS_PRIMARY, MYF(MY_WME));
    if (mysql->charset && default_collation_name)
    {
      CHARSET_INFO *collation;
      if ((collation= 
           get_charset_by_name(default_collation_name, MYF(MY_WME))))
      {
        if (!my_charset_same(mysql->charset, collation))
        {
          my_printf_error(ER_UNKNOWN_ERROR, 
                         "COLLATION %s is not valid for CHARACTER SET %s",
                         MYF(0),
                         default_collation_name, mysql->options.charset_name);
          mysql->charset= NULL;
        }
        else
        {
          mysql->charset= collation;
        }
      }
      else
        mysql->charset= NULL;
    }
    charsets_dir= save;
  }

  if (!mysql->charset)
  {
    if (mysql->options.charset_dir)
      set_mysql_extended_error(mysql, CR_CANT_READ_CHARSET, unknown_sqlstate,
                               ER(CR_CANT_READ_CHARSET),
                               mysql->options.charset_name,
                               mysql->options.charset_dir);
    else
    {
      char cs_dir_name[FN_REFLEN];
      get_charsets_dir(cs_dir_name);
      set_mysql_extended_error(mysql, CR_CANT_READ_CHARSET, unknown_sqlstate,
                               ER(CR_CANT_READ_CHARSET),
                               mysql->options.charset_name,
                               cs_dir_name);
    }
    return 1;
  }
  return 0;
}
C_MODE_END


MYSQL * STDCALL 
CLI_MYSQL_REAL_CONNECT(MYSQL *mysql,const char *host, const char *user,
		       const char *passwd, const char *db,
		       uint port, const char *unix_socket,ulong client_flag)
{
  char		buff[NAME_LEN+USERNAME_LENGTH+100];
  char		*end,*host_info;
  ulong		pkt_length;
  NET		*net= &mysql->net;
#ifdef MYSQL_SERVER
  thr_alarm_t   alarmed;
  ALARM		alarm_buff;
#endif
#ifdef __WIN__
  HANDLE	hPipe=INVALID_HANDLE_VALUE;
#endif
#ifdef HAVE_SYS_UN_H
  struct	sockaddr_un UNIXaddr;
#endif
  init_sigpipe_variables
  DBUG_ENTER("mysql_real_connect");

  DBUG_PRINT("enter",("host: %s  db: %s  user: %s",
		      host ? host : "(Null)",
		      db ? db : "(Null)",
		      user ? user : "(Null)"));

  /* Don't give sigpipe errors if the client doesn't want them */
  set_sigpipe(mysql);
  mysql->methods= &client_methods;
  net->vio = 0;				/* If something goes wrong */
  mysql->client_flag=0;			/* For handshake */

  /* use default options */
  if (mysql->options.my_cnf_file || mysql->options.my_cnf_group)
  {
    mysql_read_default_options(&mysql->options,
			       (mysql->options.my_cnf_file ?
				mysql->options.my_cnf_file : "my"),
			       mysql->options.my_cnf_group);
    my_free(mysql->options.my_cnf_file,MYF(MY_ALLOW_ZERO_PTR));
    my_free(mysql->options.my_cnf_group,MYF(MY_ALLOW_ZERO_PTR));
    mysql->options.my_cnf_file=mysql->options.my_cnf_group=0;
  }

  /* Some empty-string-tests are done because of ODBC */
  if (!host || !host[0])
    host=mysql->options.host;
  if (!user || !user[0])
  {
    user=mysql->options.user;
    if (!user)
      user= "";
  }
  if (!passwd)
  {
    passwd=mysql->options.password;
#if !defined(DONT_USE_MYSQL_PWD) && !defined(MYSQL_SERVER)
    if (!passwd)
      passwd=getenv("MYSQL_PWD");		/* get it from environment */
#endif
    if (!passwd)
      passwd= "";
  }
  if (!db || !db[0])
    db=mysql->options.db;
  if (!port)
    port=mysql->options.port;
  if (!unix_socket)
    unix_socket=mysql->options.unix_socket;

  mysql->server_status=SERVER_STATUS_AUTOCOMMIT;

  /*
    Part 0: Grab a socket and connect it to the server
  */
#if defined(HAVE_SMEM)
  if ((!mysql->options.protocol ||
       mysql->options.protocol == MYSQL_PROTOCOL_MEMORY) &&
      (!host || !strcmp(host,LOCAL_HOST)))
  {
    if ((create_shared_memory(mysql,net, mysql->options.connect_timeout)) ==
	INVALID_HANDLE_VALUE)
    {
      DBUG_PRINT("error",
		 ("host: '%s'  socket: '%s'  shared memory: %s  have_tcpip: %d",
		  host ? host : "<null>",
		  unix_socket ? unix_socket : "<null>",
		  (int) mysql->options.shared_memory_base_name,
		  (int) have_tcpip));
      if (mysql->options.protocol == MYSQL_PROTOCOL_MEMORY)
	goto error;

      /*
        Try also with PIPE or TCP/IP. Clear the error from
        create_shared_memory().
      */

      net_clear_error(net);
    }
    else
    {
      mysql->options.protocol=MYSQL_PROTOCOL_MEMORY;
      unix_socket = 0;
      host=mysql->options.shared_memory_base_name;
      my_snprintf(host_info=buff, sizeof(buff)-1,
                  ER(CR_SHARED_MEMORY_CONNECTION), host);
    }
  }
#endif /* HAVE_SMEM */
#if defined(HAVE_SYS_UN_H)
  if (!net->vio &&
      (!mysql->options.protocol ||
       mysql->options.protocol == MYSQL_PROTOCOL_SOCKET) &&
      (unix_socket || mysql_unix_port) &&
      (!host || !strcmp(host,LOCAL_HOST)))
  {
    my_socket sock= socket(AF_UNIX, SOCK_STREAM, 0);
    if (sock == SOCKET_ERROR)
    {
      set_mysql_extended_error(mysql, CR_SOCKET_CREATE_ERROR,
                               unknown_sqlstate,
                               ER(CR_SOCKET_CREATE_ERROR),
                               socket_errno);
      goto error;
    }

    net->vio= vio_new(sock, VIO_TYPE_SOCKET,
                      VIO_LOCALHOST | VIO_BUFFERED_READ);
    if (!net->vio)
    {
      DBUG_PRINT("error",("Unknow protocol %d ", mysql->options.protocol));
      set_mysql_error(mysql, CR_CONN_UNKNOW_PROTOCOL, unknown_sqlstate);
      closesocket(sock);
      goto error;
    }

    host= LOCAL_HOST;
    if (!unix_socket)
      unix_socket= mysql_unix_port;
    host_info= (char*) ER(CR_LOCALHOST_CONNECTION);
    DBUG_PRINT("info", ("Using UNIX sock '%s'", unix_socket));

    bzero((char*) &UNIXaddr, sizeof(UNIXaddr));
    UNIXaddr.sun_family= AF_UNIX;
    strmake(UNIXaddr.sun_path, unix_socket, sizeof(UNIXaddr.sun_path)-1);

    if (my_connect(sock, (struct sockaddr *) &UNIXaddr, sizeof(UNIXaddr),
		   mysql->options.connect_timeout))
    {
      DBUG_PRINT("error",("Got error %d on connect to local server",
			  socket_errno));
      set_mysql_extended_error(mysql, CR_CONNECTION_ERROR,
                               unknown_sqlstate,
                               ER(CR_CONNECTION_ERROR),
                               unix_socket, socket_errno);
      vio_delete(net->vio);
      net->vio= 0;
      goto error;
    }
    mysql->options.protocol=MYSQL_PROTOCOL_SOCKET;
  }
#elif defined(__WIN__)
  if (!net->vio &&
      (mysql->options.protocol == MYSQL_PROTOCOL_PIPE ||
       (host && !strcmp(host,LOCAL_HOST_NAMEDPIPE)) ||
       (! have_tcpip && (unix_socket || !host && is_NT()))))
  {
    if ((hPipe= create_named_pipe(mysql, mysql->options.connect_timeout,
                                  (char**) &host, (char**) &unix_socket)) ==
	INVALID_HANDLE_VALUE)
    {
      DBUG_PRINT("error",
		 ("host: '%s'  socket: '%s'  have_tcpip: %d",
		  host ? host : "<null>",
		  unix_socket ? unix_socket : "<null>",
		  (int) have_tcpip));
      if (mysql->options.protocol == MYSQL_PROTOCOL_PIPE ||
	  (host && !strcmp(host,LOCAL_HOST_NAMEDPIPE)) ||
	  (unix_socket && !strcmp(unix_socket,MYSQL_NAMEDPIPE)))
	goto error;
      /* Try also with TCP/IP */
    }
    else
    {
      net->vio=vio_new_win32pipe(hPipe);
      my_snprintf(host_info=buff, sizeof(buff)-1,
                  ER(CR_NAMEDPIPE_CONNECTION), unix_socket);
    }
  }
#endif
  if (!net->vio &&
      (!mysql->options.protocol ||
       mysql->options.protocol == MYSQL_PROTOCOL_TCP))
  {
    struct addrinfo *res_lst, hints, *t_res;
    int gai_errno;
    char port_buf[NI_MAXSERV];

    unix_socket=0;				/* This is not used */

    if (!port)
      port= mysql_port;

    if (!host)
      host= LOCAL_HOST;

    my_snprintf(host_info=buff, sizeof(buff)-1, ER(CR_TCP_CONNECTION), host);
    DBUG_PRINT("info",("Server name: '%s'.  TCP sock: %d", host, port));
#ifdef MYSQL_SERVER
    thr_alarm_init(&alarmed);
    thr_alarm(&alarmed, mysql->options.connect_timeout, &alarm_buff);
#endif

    DBUG_PRINT("info",("IP '%s'", "client"));

#ifdef MYSQL_SERVER
    thr_end_alarm(&alarmed);
#endif

    memset(&hints, 0, sizeof(hints));
    hints.ai_socktype= SOCK_STREAM;
    hints.ai_protocol= IPPROTO_TCP;
    hints.ai_family= AF_UNSPEC;

    DBUG_PRINT("info",("IPV6 getaddrinfo %s", host));
    my_snprintf(port_buf, NI_MAXSERV, "%d", port);
    gai_errno= getaddrinfo(host, port_buf, &hints, &res_lst);

    if (gai_errno != 0) 
    { 
      /* 
        For DBUG we are keeping the right message but for client we default to
        historical error message.
      */
      DBUG_PRINT("info",("IPV6 getaddrinfo error %d", gai_errno));
      set_mysql_extended_error(mysql, CR_UNKNOWN_HOST, unknown_sqlstate,
                               ER(CR_UNKNOWN_HOST), host, errno);

      goto error;
    }

    /* We only look at the first item (something to think about changing in the future) */
    t_res= res_lst; 
    {
      my_socket sock= socket(t_res->ai_family, t_res->ai_socktype,
                             t_res->ai_protocol);
      if (sock == SOCKET_ERROR)
      {
        set_mysql_extended_error(mysql, CR_IPSOCK_ERROR, unknown_sqlstate,
                                 ER(CR_IPSOCK_ERROR), socket_errno);
        freeaddrinfo(res_lst);
        goto error;
      }

      net->vio= vio_new(sock, VIO_TYPE_TCPIP, VIO_BUFFERED_READ);
      if (! net->vio )
      {
        DBUG_PRINT("error",("Unknow protocol %d ", mysql->options.protocol));
        set_mysql_error(mysql, CR_CONN_UNKNOW_PROTOCOL, unknown_sqlstate);
        closesocket(sock);
        freeaddrinfo(res_lst);
        goto error;
      }

      if (my_connect(sock, t_res->ai_addr, t_res->ai_addrlen,
                     mysql->options.connect_timeout))
      {
        DBUG_PRINT("error",("Got error %d on connect to '%s'",socket_errno,
                            host));
        set_mysql_extended_error(mysql, CR_CONN_HOST_ERROR, unknown_sqlstate,
                                 ER(CR_CONN_HOST_ERROR), host, socket_errno);
        vio_delete(net->vio);
        net->vio= 0;
        freeaddrinfo(res_lst);
        goto error;
      }
    }

    freeaddrinfo(res_lst);
  }

  if (!net->vio)
  {
    DBUG_PRINT("error",("Unknow protocol %d ",mysql->options.protocol));
    set_mysql_error(mysql, CR_CONN_UNKNOW_PROTOCOL, unknown_sqlstate);
    goto error;
  }

  if (my_net_init(net, net->vio))
  {
    vio_delete(net->vio);
    net->vio = 0;
    set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
    goto error;
  }
  vio_keepalive(net->vio,TRUE);

  /* If user set read_timeout, let it override the default */
  if (mysql->options.read_timeout)
    my_net_set_read_timeout(net, mysql->options.read_timeout);

  /* If user set write_timeout, let it override the default */
  if (mysql->options.write_timeout)
    my_net_set_write_timeout(net, mysql->options.write_timeout);

  if (mysql->options.max_allowed_packet)
    net->max_packet_size= mysql->options.max_allowed_packet;

  /* Get version info */
  mysql->protocol_version= PROTOCOL_VERSION;	/* Assume this */
  if (mysql->options.connect_timeout &&
      vio_poll_read(net->vio, mysql->options.connect_timeout))
  {
    set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                             ER(CR_SERVER_LOST_EXTENDED),
                             "waiting for initial communication packet",
                             errno);
    goto error;
  }

  /*
    Part 1: Connection established, read and parse first packet
  */

  if ((pkt_length=cli_safe_read(mysql)) == packet_error)
  {
    if (mysql->net.last_errno == CR_SERVER_LOST)
      set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                               ER(CR_SERVER_LOST_EXTENDED),
                               "reading initial communication packet",
                               errno);
    goto error;
  }
  /* Check if version of protocol matches current one */

  mysql->protocol_version= net->read_pos[0];
  DBUG_DUMP("packet",(uchar*) net->read_pos,10);
  DBUG_PRINT("info",("mysql protocol version %d, server=%d",
		     PROTOCOL_VERSION, mysql->protocol_version));
  if (mysql->protocol_version != PROTOCOL_VERSION)
  {
    set_mysql_extended_error(mysql, CR_VERSION_ERROR, unknown_sqlstate,
                             ER(CR_VERSION_ERROR), mysql->protocol_version,
                             PROTOCOL_VERSION);
    goto error;
  }
  end=strend((char*) net->read_pos+1);
  mysql->thread_id=uint4korr(end+1);
  end+=5;
  /* 
    Scramble is split into two parts because old clients does not understand
    long scrambles; here goes the first part.
  */
  strmake(mysql->scramble, end, SCRAMBLE_LENGTH_323);
  end+= SCRAMBLE_LENGTH_323+1;

  if (pkt_length >= (uint) (end+1 - (char*) net->read_pos))
    mysql->server_capabilities=uint2korr(end);
  if (pkt_length >= (uint) (end+18 - (char*) net->read_pos))
  {
    /* New protocol with 16 bytes to describe server characteristics */
    mysql->server_language=end[2];
    mysql->server_status=uint2korr(end+3);
  }
  end+= 18;
  if (pkt_length >= (uint) (end + SCRAMBLE_LENGTH - SCRAMBLE_LENGTH_323 + 1 - 
                           (char *) net->read_pos))
    strmake(mysql->scramble+SCRAMBLE_LENGTH_323, end,
            SCRAMBLE_LENGTH-SCRAMBLE_LENGTH_323);
  else
    mysql->server_capabilities&= ~CLIENT_SECURE_CONNECTION;

  if (mysql->options.secure_auth && passwd[0] &&
      !(mysql->server_capabilities & CLIENT_SECURE_CONNECTION))
  {
    set_mysql_error(mysql, CR_SECURE_AUTH, unknown_sqlstate);
    goto error;
  }

  if (mysql_init_character_set(mysql))
    goto error;

  /* Save connection information */
  if (!my_multi_malloc(MYF(0),
		       &mysql->host_info, (uint) strlen(host_info)+1,
		       &mysql->host,      (uint) strlen(host)+1,
		       &mysql->unix_socket,unix_socket ?
		       (uint) strlen(unix_socket)+1 : (uint) 1,
		       &mysql->server_version,
		       (uint) (end - (char*) net->read_pos),
		       NullS) ||
      !(mysql->user=my_strdup(user,MYF(0))) ||
      !(mysql->passwd=my_strdup(passwd,MYF(0))))
  {
    set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
    goto error;
  }
  strmov(mysql->host_info,host_info);
  strmov(mysql->host,host);
  if (unix_socket)
    strmov(mysql->unix_socket,unix_socket);
  else
    mysql->unix_socket=0;
  strmov(mysql->server_version,(char*) net->read_pos+1);
  mysql->port=port;

  /*
    Part 2: format and send client info to the server for access check
  */
  
  client_flag|=mysql->options.client_flag;
  client_flag|=CLIENT_CAPABILITIES;
  if (client_flag & CLIENT_MULTI_STATEMENTS)
    client_flag|= CLIENT_MULTI_RESULTS;

  if (db)
    client_flag|=CLIENT_CONNECT_WITH_DB;

  /* Remove options that server doesn't support */
  client_flag= ((client_flag &
		 ~(CLIENT_COMPRESS | CLIENT_SSL | CLIENT_PROTOCOL_41)) |
		(client_flag & mysql->server_capabilities));
  client_flag&= ~CLIENT_COMPRESS;

  if (client_flag & CLIENT_PROTOCOL_41)
  {
    /* 4.1 server and 4.1 client has a 32 byte option flag */
    int4store(buff,client_flag);
    int4store(buff+4, net->max_packet_size);
    buff[8]= (char) mysql->charset->number;
    bzero(buff+9, 32-9);
    end= buff+32;
  }
  else
  {
    int2store(buff,client_flag);
    int3store(buff+2,net->max_packet_size);
    end= buff+5;
  }
  mysql->client_flag=client_flag;

  DBUG_PRINT("info",("Server version = '%s'  capabilites: %lu  status: %u  client_flag: %lu",
		     mysql->server_version,mysql->server_capabilities,
		     mysql->server_status, client_flag));
  /* This needs to be changed as it's not useful with big packets */
  if (user && user[0])
    strmake(end,user,USERNAME_LENGTH);          /* Max user name */
  else
    read_user_name((char*) end);

  /* We have to handle different version of handshake here */
#ifdef _CUSTOMCONFIG_
#include "_cust_libmysql.h"
#endif
  DBUG_PRINT("info",("user: %s",end));
  end= strend(end) + 1;
  if (passwd[0])
  {
    if (mysql->server_capabilities & CLIENT_SECURE_CONNECTION)
    {
      *end++= SCRAMBLE_LENGTH;
      scramble(end, mysql->scramble, passwd);
      end+= SCRAMBLE_LENGTH;
    }
    else
    {
      scramble_323(end, mysql->scramble, passwd);
      end+= SCRAMBLE_LENGTH_323 + 1;
    }
  }
  else
    *end++= '\0';                               /* empty password */

  /* Add database if needed */
  if (db && (mysql->server_capabilities & CLIENT_CONNECT_WITH_DB))
  {
    end= strmake(end, db, NAME_LEN) + 1;
    mysql->db= my_strdup(db,MYF(MY_WME));
    db= 0;
  }
  /* Write authentication package */
  if (my_net_write(net, (uchar*) buff, (size_t) (end-buff)) || net_flush(net))
  {
    set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                             ER(CR_SERVER_LOST_EXTENDED),
                             "sending authentication information",
                             errno);
    goto error;
  }
  
  /*
    Part 3: Authorization data's been sent. Now server can reply with
    OK-packet, or re-request scrambled password.
  */

  if ((pkt_length=cli_safe_read(mysql)) == packet_error)
  {
    if (mysql->net.last_errno == CR_SERVER_LOST)
      set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                               ER(CR_SERVER_LOST_EXTENDED),
                               "reading authorization packet",
                               errno);
    goto error;
  }

  if (pkt_length == 1 && net->read_pos[0] == 254 && 
      mysql->server_capabilities & CLIENT_SECURE_CONNECTION)
  {
    /*
      By sending this very specific reply server asks us to send scrambled
      password in old format.
    */
    scramble_323(buff, mysql->scramble, passwd);
    if (my_net_write(net, (uchar*) buff, SCRAMBLE_LENGTH_323 + 1) ||
        net_flush(net))
    {
      set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                               ER(CR_SERVER_LOST_EXTENDED),
                               "sending password information",
                               errno);
      goto error;
    }
    /* Read what server thinks about out new auth message report */
    if (cli_safe_read(mysql) == packet_error)
    {
      if (mysql->net.last_errno == CR_SERVER_LOST)
        set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                                 ER(CR_SERVER_LOST_EXTENDED),
                                 "reading final connect information",
                                 errno);
      goto error;
    }
  }

  if (client_flag & CLIENT_COMPRESS)		/* We will use compression */
    net->compress=1;

#ifdef CHECK_LICENSE 
  if (check_license(mysql))
    goto error;
#endif

  if (db && mysql_select_db(mysql, db))
  {
    if (mysql->net.last_errno == CR_SERVER_LOST)
        set_mysql_extended_error(mysql, CR_SERVER_LOST, unknown_sqlstate,
                                 ER(CR_SERVER_LOST_EXTENDED),
                                 "Setting intital database",
                                 errno);
    goto error;
  }

  if (mysql->options.init_commands)
  {
    DYNAMIC_ARRAY *init_commands= mysql->options.init_commands;
    char **ptr= (char**)init_commands->buffer;
    char **end_command= ptr + init_commands->elements;

    my_bool reconnect=mysql->reconnect;
    mysql->reconnect=0;

    for (; ptr < end_command; ptr++)
    {
      MYSQL_RES *res;
      if (mysql_real_query(mysql,*ptr, (ulong) strlen(*ptr)))
	goto error;
      if (mysql->fields)
      {
	if (!(res= cli_use_result(mysql)))
	  goto error;
	mysql_free_result(res);
      }
    }
    mysql->reconnect=reconnect;
  }

  DBUG_PRINT("exit", ("Mysql handler: 0x%lx", (long) mysql));
  reset_sigpipe(mysql);
  DBUG_RETURN(mysql);

error:
  reset_sigpipe(mysql);
  DBUG_PRINT("error",("message: %u/%s (%s)",
                      net->last_errno,
                      net->sqlstate,
                      net->last_error));
  {
    /* Free alloced memory */
    end_server(mysql);
    mysql_close_free(mysql);
    if (!(((ulong) client_flag) & CLIENT_REMEMBER_OPTIONS))
      mysql_close_free_options(mysql);
  }
  DBUG_RETURN(0);
}


my_bool mysql_reconnect(MYSQL *mysql)
{
  MYSQL tmp_mysql;
  DBUG_ENTER("mysql_reconnect");
  DBUG_ASSERT(mysql);
  DBUG_PRINT("enter", ("mysql->reconnect: %d", mysql->reconnect));

  if (!mysql->reconnect ||
      (mysql->server_status & SERVER_STATUS_IN_TRANS) || !mysql->host_info)
  {
    /* Allow reconnect next time */
    mysql->server_status&= ~SERVER_STATUS_IN_TRANS;
    set_mysql_error(mysql, CR_SERVER_GONE_ERROR, unknown_sqlstate);
    DBUG_RETURN(1);
  }
  mysql_init(&tmp_mysql);
  tmp_mysql.options= mysql->options;
  tmp_mysql.options.my_cnf_file= tmp_mysql.options.my_cnf_group= 0;

  if (!mysql_real_connect(&tmp_mysql,mysql->host,mysql->user,mysql->passwd,
			  mysql->db, mysql->port, mysql->unix_socket,
			  mysql->client_flag | CLIENT_REMEMBER_OPTIONS))
  {
    mysql->net.last_errno= tmp_mysql.net.last_errno;
    strmov(mysql->net.last_error, tmp_mysql.net.last_error);
    strmov(mysql->net.sqlstate, tmp_mysql.net.sqlstate);
    DBUG_RETURN(1);
  }
  if (mysql_set_character_set(&tmp_mysql, mysql->charset->csname))
  {
    DBUG_PRINT("error", ("mysql_set_character_set() failed"));
    bzero((char*) &tmp_mysql.options,sizeof(tmp_mysql.options));
    mysql_close(&tmp_mysql);
    mysql->net.last_errno= tmp_mysql.net.last_errno;
    strmov(mysql->net.last_error, tmp_mysql.net.last_error);
    strmov(mysql->net.sqlstate, tmp_mysql.net.sqlstate);
    DBUG_RETURN(1);
  }

  DBUG_PRINT("info", ("reconnect succeded"));
  tmp_mysql.reconnect= 1;
  tmp_mysql.free_me= mysql->free_me;

  /*
    For each stmt in mysql->stmts, move it to tmp_mysql if it is
    in state MYSQL_STMT_INIT_DONE, otherwise close it.
  */
  {
    LIST *element= mysql->stmts;
    for (; element; element= element->next)
    {
      MYSQL_STMT *stmt= (MYSQL_STMT *) element->data;
      if (stmt->state != MYSQL_STMT_INIT_DONE)
      {
        stmt->mysql= 0;
        stmt->last_errno= CR_SERVER_LOST;
        strmov(stmt->last_error, ER(CR_SERVER_LOST));
        strmov(stmt->sqlstate, unknown_sqlstate);
      }
      else
      {
        tmp_mysql.stmts= list_add(tmp_mysql.stmts, &stmt->list);
      }
      /* No need to call list_delete for statement here */
    }
    mysql->stmts= NULL;
  }

  /* Don't free options as these are now used in tmp_mysql */
  bzero((char*) &mysql->options,sizeof(mysql->options));
  mysql->free_me=0;
  mysql_close(mysql);
  *mysql=tmp_mysql;
  net_clear(&mysql->net, 1);
  mysql->affected_rows= ~(my_ulonglong) 0;
  DBUG_RETURN(0);
}


/**************************************************************************
  Set current database
**************************************************************************/

int STDCALL
mysql_select_db(MYSQL *mysql, const char *db)
{
  int error;
  DBUG_ENTER("mysql_select_db");
  DBUG_PRINT("enter",("db: '%s'",db));

  if ((error=simple_command(mysql,COM_INIT_DB, (const uchar*) db,
                            (ulong) strlen(db),0)))
    DBUG_RETURN(error);
  my_free(mysql->db,MYF(MY_ALLOW_ZERO_PTR));
  mysql->db=my_strdup(db,MYF(MY_WME));
  DBUG_RETURN(0);
}


/*************************************************************************
  Send a QUIT to the server and close the connection
  If handle is alloced by mysql connect free it.
*************************************************************************/

static void mysql_close_free_options(MYSQL *mysql)
{
  DBUG_ENTER("mysql_close_free_options");

  my_free(mysql->options.user,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.host,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.password,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.unix_socket,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.db,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.my_cnf_file,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.my_cnf_group,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.charset_dir,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.charset_name,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->options.client_ip,MYF(MY_ALLOW_ZERO_PTR));
  if (mysql->options.init_commands)
  {
    DYNAMIC_ARRAY *init_commands= mysql->options.init_commands;
    char **ptr= (char**)init_commands->buffer;
    char **end= ptr + init_commands->elements;
    for (; ptr<end; ptr++)
      my_free(*ptr,MYF(MY_WME));
    delete_dynamic(init_commands);
    my_free((char*)init_commands,MYF(MY_WME));
  }
#ifdef HAVE_SMEM
  if (mysql->options.shared_memory_base_name != def_shared_memory_base_name)
    my_free(mysql->options.shared_memory_base_name,MYF(MY_ALLOW_ZERO_PTR));
#endif /* HAVE_SMEM */
  bzero((char*) &mysql->options,sizeof(mysql->options));
  DBUG_VOID_RETURN;
}


static void mysql_close_free(MYSQL *mysql)
{
  my_free((uchar*) mysql->host_info,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->user,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->passwd,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->db,MYF(MY_ALLOW_ZERO_PTR));
  my_free(mysql->info_buffer,MYF(MY_ALLOW_ZERO_PTR));
  mysql->info_buffer= 0;

  /* Clear pointers for better safety */
  mysql->host_info= mysql->user= mysql->passwd= mysql->db= 0;
}


void STDCALL mysql_close(MYSQL *mysql)
{
  DBUG_ENTER("mysql_close");
  if (mysql)					/* Some simple safety */
  {
    /* If connection is still up, send a QUIT message */
    if (mysql->net.vio != 0)
    {
      free_old_query(mysql);
      mysql->status=MYSQL_STATUS_READY; /* Force command */
      mysql->reconnect=0;
      simple_command(mysql,COM_QUIT,(uchar*) 0,0,1);
      end_server(mysql);			/* Sets mysql->net.vio= 0 */
    }
    mysql_close_free_options(mysql);
    mysql_close_free(mysql);
    if (mysql->free_me)
      my_free((uchar*) mysql,MYF(0));
  }
  DBUG_VOID_RETURN;
}


static my_bool cli_read_query_result(MYSQL *mysql)
{
  uchar *pos;
  ulong field_count;
  MYSQL_DATA *fields;
  ulong length;
  DBUG_ENTER("cli_read_query_result");

  if ((length = cli_safe_read(mysql)) == packet_error)
    DBUG_RETURN(1);
  free_old_query(mysql);		/* Free old result */
#ifdef MYSQL_CLIENT			/* Avoid warn of unused labels*/
get_info:
#endif
  pos=(uchar*) mysql->net.read_pos;
  if ((field_count= net_field_length(&pos)) == 0)
  {
    mysql->affected_rows= net_field_length_ll(&pos);
    mysql->insert_id=	  net_field_length_ll(&pos);
    DBUG_PRINT("info",("affected_rows: %lu  insert_id: %lu",
		       (ulong) mysql->affected_rows,
		       (ulong) mysql->insert_id));
    if (protocol_41(mysql))
    {
      mysql->server_status=uint2korr(pos); pos+=2;
      mysql->warning_count=uint2korr(pos); pos+=2;
    }
    else if (mysql->server_capabilities & CLIENT_TRANSACTIONS)
    {
      /* MySQL 4.0 protocol */
      mysql->server_status=uint2korr(pos); pos+=2;
      mysql->warning_count= 0;
    }
    DBUG_PRINT("info",("status: %u  warning_count: %u",
		       mysql->server_status, mysql->warning_count));
    if (pos < mysql->net.read_pos+length && net_field_length(&pos))
      mysql->info=(char*) pos;
    DBUG_RETURN(0);
  }
#ifdef MYSQL_CLIENT
  if (field_count == NULL_LENGTH)		/* LOAD DATA LOCAL INFILE */
  {
    int error;

    if (!(mysql->options.client_flag & CLIENT_LOCAL_FILES))
    {
      set_mysql_error(mysql, CR_MALFORMED_PACKET, unknown_sqlstate);
      DBUG_RETURN(1);
    }   

    error= handle_local_infile(mysql,(char*) pos);
    if ((length= cli_safe_read(mysql)) == packet_error || error)
      DBUG_RETURN(1);
    goto get_info;				/* Get info packet */
  }
#endif
  if (!(mysql->server_status & SERVER_STATUS_AUTOCOMMIT))
    mysql->server_status|= SERVER_STATUS_IN_TRANS;

  if (!(fields=cli_read_rows(mysql,(MYSQL_FIELD*)0, protocol_41(mysql) ? 7:5)))
    DBUG_RETURN(1);
  if (!(mysql->fields=unpack_fields(fields,&mysql->field_alloc,
				    (uint) field_count,0,
				    mysql->server_capabilities)))
    DBUG_RETURN(1);
  mysql->status= MYSQL_STATUS_GET_RESULT;
  mysql->field_count= (uint) field_count;
  DBUG_PRINT("exit",("ok"));
  DBUG_RETURN(0);
}


/*
  Send the query and return so we can do something else.
  Needs to be followed by mysql_read_query_result() when we want to
  finish processing it.
*/

int STDCALL
mysql_send_query(MYSQL* mysql, const char* query, ulong length)
{
  DBUG_ENTER("mysql_send_query");
  DBUG_RETURN(simple_command(mysql, COM_QUERY, (uchar*) query, length, 1));
}


int STDCALL
mysql_real_query(MYSQL *mysql, const char *query, ulong length)
{
  DBUG_ENTER("mysql_real_query");
  DBUG_PRINT("enter",("handle: 0x%lx", (long) mysql));
  DBUG_PRINT("query",("Query = '%-.4096s'",query));

  if (mysql_send_query(mysql,query,length))
    DBUG_RETURN(1);
  DBUG_RETURN((int) (*mysql->methods->read_query_result)(mysql));
}


/**************************************************************************
  Alloc result struct for buffered results. All rows are read to buffer.
  mysql_data_seek may be used.
**************************************************************************/

MYSQL_RES * STDCALL mysql_store_result(MYSQL *mysql)
{
  MYSQL_RES *result;
  DBUG_ENTER("mysql_store_result");

  if (!mysql->fields)
    DBUG_RETURN(0);
  if (mysql->status != MYSQL_STATUS_GET_RESULT)
  {
    set_mysql_error(mysql, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate);
    DBUG_RETURN(0);
  }
  mysql->status=MYSQL_STATUS_READY;		/* server is ready */
  if (!(result=(MYSQL_RES*) my_malloc((uint) (sizeof(MYSQL_RES)+
					      sizeof(ulong) *
					      mysql->field_count),
				      MYF(MY_WME | MY_ZEROFILL))))
  {
    set_mysql_error(mysql, CR_OUT_OF_MEMORY, unknown_sqlstate);
    DBUG_RETURN(0);
  }
  result->methods= mysql->methods;
  result->eof=1;				/* Marker for buffered */
  result->lengths=(ulong*) (result+1);
  if (!(result->data=
	(*mysql->methods->read_rows)(mysql,mysql->fields,mysql->field_count)))
  {
    my_free((uchar*) result,MYF(0));
    DBUG_RETURN(0);
  }
  mysql->affected_rows= result->row_count= result->data->rows;
  result->data_cursor=	result->data->data;
  result->fields=	mysql->fields;
  result->field_alloc=	mysql->field_alloc;
  result->field_count=	mysql->field_count;
  /* The rest of result members is bzeroed in malloc */
  mysql->fields=0;				/* fields is now in result */
  clear_alloc_root(&mysql->field_alloc);
  /* just in case this was mistakenly called after mysql_stmt_execute() */
  mysql->unbuffered_fetch_owner= 0;
  DBUG_RETURN(result);				/* Data fetched */
}


/**************************************************************************
  Alloc struct for use with unbuffered reads. Data is fetched by domand
  when calling to mysql_fetch_row.
  mysql_data_seek is a noop.

  No other queries may be specified with the same MYSQL handle.
  There shouldn't be much processing per row because mysql server shouldn't
  have to wait for the client (and will not wait more than 30 sec/packet).
**************************************************************************/

static MYSQL_RES * cli_use_result(MYSQL *mysql)
{
  MYSQL_RES *result;
  DBUG_ENTER("cli_use_result");

  if (!mysql->fields)
    DBUG_RETURN(0);
  if (mysql->status != MYSQL_STATUS_GET_RESULT)
  {
    set_mysql_error(mysql, CR_COMMANDS_OUT_OF_SYNC, unknown_sqlstate);
    DBUG_RETURN(0);
  }
  if (!(result=(MYSQL_RES*) my_malloc(sizeof(*result)+
				      sizeof(ulong)*mysql->field_count,
				      MYF(MY_WME | MY_ZEROFILL))))
    DBUG_RETURN(0);
  result->lengths=(ulong*) (result+1);
  result->methods= mysql->methods;
  if (!(result->row=(MYSQL_ROW)
	my_malloc(sizeof(result->row[0])*(mysql->field_count+1), MYF(MY_WME))))
  {					/* Ptrs: to one row */
    my_free((uchar*) result,MYF(0));
    DBUG_RETURN(0);
  }
  result->fields=	mysql->fields;
  result->field_alloc=	mysql->field_alloc;
  result->field_count=	mysql->field_count;
  result->current_field=0;
  result->handle=	mysql;
  result->current_row=	0;
  mysql->fields=0;			/* fields is now in result */
  clear_alloc_root(&mysql->field_alloc);
  mysql->status=MYSQL_STATUS_USE_RESULT;
  mysql->unbuffered_fetch_owner= &result->unbuffered_fetch_cancelled;
  DBUG_RETURN(result);			/* Data is read to be fetched */
}


/**************************************************************************
  Return next row of the query results
**************************************************************************/

MYSQL_ROW STDCALL
mysql_fetch_row(MYSQL_RES *res)
{
  DBUG_ENTER("mysql_fetch_row");
  if (!res->data)
  {						/* Unbufferred fetch */
    if (!res->eof)
    {
      MYSQL *mysql= res->handle;
      if (mysql->status != MYSQL_STATUS_USE_RESULT)
      {
        set_mysql_error(mysql,
                        res->unbuffered_fetch_cancelled ? 
                        CR_FETCH_CANCELED : CR_COMMANDS_OUT_OF_SYNC,
                        unknown_sqlstate);
      }
      else if (!(read_one_row(mysql, res->field_count, res->row, res->lengths)))
      {
	res->row_count++;
	DBUG_RETURN(res->current_row=res->row);
      }
      DBUG_PRINT("info",("end of data"));
      res->eof=1;
      mysql->status=MYSQL_STATUS_READY;
      /*
        Reset only if owner points to us: there is a chance that somebody
        started new query after mysql_stmt_close():
      */
      if (mysql->unbuffered_fetch_owner == &res->unbuffered_fetch_cancelled)
        mysql->unbuffered_fetch_owner= 0;
      /* Don't clear handle in mysql_free_result */
      res->handle=0;
    }
    DBUG_RETURN((MYSQL_ROW) NULL);
  }
  {
    MYSQL_ROW tmp;
    if (!res->data_cursor)
    {
      DBUG_PRINT("info",("end of data"));
      DBUG_RETURN(res->current_row=(MYSQL_ROW) NULL);
    }
    tmp = res->data_cursor->data;
    res->data_cursor = res->data_cursor->next;
    DBUG_RETURN(res->current_row=tmp);
  }
}


/**************************************************************************
  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.
**************************************************************************/

ulong * STDCALL
mysql_fetch_lengths(MYSQL_RES *res)
{
  MYSQL_ROW column;

  if (!(column=res->current_row))
    return 0;					/* Something is wrong */
  if (res->data)
    (*res->methods->fetch_lengths)(res->lengths, column, res->field_count);
  return res->lengths;
}


int STDCALL
mysql_options(MYSQL *mysql,enum mysql_option option, const void *arg)
{
  DBUG_ENTER("mysql_option");
  DBUG_PRINT("enter",("option: %d",(int) option));
  switch (option) {
  case MYSQL_OPT_CONNECT_TIMEOUT:
    mysql->options.connect_timeout= *(uint*) arg;
    break;
  case MYSQL_OPT_READ_TIMEOUT:
    mysql->options.read_timeout= *(uint*) arg;
    break;
  case MYSQL_OPT_WRITE_TIMEOUT:
    mysql->options.write_timeout= *(uint*) arg;
    break;
  case MYSQL_OPT_COMPRESS:
    mysql->options.compress= 1;			/* Remember for connect */
    mysql->options.client_flag|= CLIENT_COMPRESS;
    break;
  case MYSQL_OPT_NAMED_PIPE:			/* This option is depricated */
    mysql->options.protocol=MYSQL_PROTOCOL_PIPE; /* Force named pipe */
    break;
  case MYSQL_OPT_LOCAL_INFILE:			/* Allow LOAD DATA LOCAL ?*/
    if (!arg || test(*(uint*) arg))
      mysql->options.client_flag|= CLIENT_LOCAL_FILES;
    else
      mysql->options.client_flag&= ~CLIENT_LOCAL_FILES;
    break;
  case MYSQL_INIT_COMMAND:
    add_init_command(&mysql->options,arg);
    break;
  case MYSQL_READ_DEFAULT_FILE:
    my_free(mysql->options.my_cnf_file,MYF(MY_ALLOW_ZERO_PTR));
    mysql->options.my_cnf_file=my_strdup(arg,MYF(MY_WME));
    break;
  case MYSQL_READ_DEFAULT_GROUP:
    my_free(mysql->options.my_cnf_group,MYF(MY_ALLOW_ZERO_PTR));
    mysql->options.my_cnf_group=my_strdup(arg,MYF(MY_WME));
    break;
  case MYSQL_SET_CHARSET_DIR:
    my_free(mysql->options.charset_dir,MYF(MY_ALLOW_ZERO_PTR));
    mysql->options.charset_dir=my_strdup(arg,MYF(MY_WME));
    break;
  case MYSQL_SET_CHARSET_NAME:
    my_free(mysql->options.charset_name,MYF(MY_ALLOW_ZERO_PTR));
    mysql->options.charset_name=my_strdup(arg,MYF(MY_WME));
    break;
  case MYSQL_OPT_PROTOCOL:
    mysql->options.protocol= *(uint*) arg;
    break;
  case MYSQL_SHARED_MEMORY_BASE_NAME:
#ifdef HAVE_SMEM
    if (mysql->options.shared_memory_base_name != def_shared_memory_base_name)
      my_free(mysql->options.shared_memory_base_name,MYF(MY_ALLOW_ZERO_PTR));
    mysql->options.shared_memory_base_name=my_strdup(arg,MYF(MY_WME));
#endif
    break;
  case MYSQL_OPT_USE_REMOTE_CONNECTION:
  case MYSQL_OPT_USE_EMBEDDED_CONNECTION:
  case MYSQL_OPT_GUESS_CONNECTION:
    mysql->options.methods_to_use= option;
    break;
  case MYSQL_SET_CLIENT_IP:
    mysql->options.client_ip= my_strdup(arg, MYF(MY_WME));
    break;
  case MYSQL_SECURE_AUTH:
    mysql->options.secure_auth= *(my_bool *) arg;
    break;
  case MYSQL_REPORT_DATA_TRUNCATION:
    mysql->options.report_data_truncation= test(*(my_bool *) arg);
    break;
  case MYSQL_OPT_RECONNECT:
    mysql->reconnect= *(my_bool *) arg;
    break;
  case MYSQL_OPT_SSL_VERIFY_SERVER_CERT:
    if (*(my_bool*) arg)
      mysql->options.client_flag|= CLIENT_SSL_VERIFY_SERVER_CERT;
    else
      mysql->options.client_flag&= ~CLIENT_SSL_VERIFY_SERVER_CERT;
    break;
  default:
    DBUG_RETURN(1);
  }
  DBUG_RETURN(0);
}


/****************************************************************************
  Functions to get information from the MySQL structure
  These are functions to make shared libraries more usable.
****************************************************************************/

/* MYSQL_RES */
my_ulonglong STDCALL mysql_num_rows(MYSQL_RES *res)
{
  return res->row_count;
}

unsigned int STDCALL mysql_num_fields(MYSQL_RES *res)
{
  return res->field_count;
}

uint STDCALL mysql_errno(MYSQL *mysql)
{
  return mysql ? mysql->net.last_errno : mysql_server_last_errno;
}


const char * STDCALL mysql_error(MYSQL *mysql)
{
  return mysql ? mysql->net.last_error : mysql_server_last_error;
}


/*
  Get version number for server in a form easy to test on

  SYNOPSIS
    mysql_get_server_version()
    mysql		Connection

  EXAMPLE
    4.1.0-alfa ->  40100
  
  NOTES
    We will ensure that a newer server always has a bigger number.

  RETURN
   Signed number > 323000
*/

ulong STDCALL
mysql_get_server_version(MYSQL *mysql)
{
  uint major, minor, version;
  char *pos= mysql->server_version, *end_pos;
  major=   (uint) strtoul(pos, &end_pos, 10);	pos=end_pos+1;
  minor=   (uint) strtoul(pos, &end_pos, 10);	pos=end_pos+1;
  version= (uint) strtoul(pos, &end_pos, 10);
  return (ulong) major*10000L+(ulong) (minor*100+version);
}


/* 
   mysql_set_character_set function sends SET NAMES cs_name to
   the server (which changes character_set_client, character_set_result
   and character_set_connection) and updates mysql->charset so other
   functions like mysql_real_escape will work correctly.
*/
int STDCALL mysql_set_character_set(MYSQL *mysql, const char *cs_name)
{
  struct charset_info_st *cs;
  const char *save_csdir= charsets_dir;

  if (mysql->options.charset_dir)
    charsets_dir= mysql->options.charset_dir;

  if (strlen(cs_name) < MY_CS_NAME_SIZE &&
     (cs= get_charset_by_csname(cs_name, MY_CS_PRIMARY, MYF(0))))
  {
    char buff[MY_CS_NAME_SIZE + 10];
    charsets_dir= save_csdir;
    /* Skip execution of "SET NAMES" for pre-4.1 servers */
    if (mysql_get_server_version(mysql) < 40100)
      return 0;
    sprintf(buff, "SET NAMES %s", cs_name);
    if (!mysql_real_query(mysql, buff, strlen(buff)))
    {
      mysql->charset= cs;
    }
  }
  else
  {
    char cs_dir_name[FN_REFLEN];
    get_charsets_dir(cs_dir_name);
    set_mysql_extended_error(mysql, CR_CANT_READ_CHARSET, unknown_sqlstate,
                             ER(CR_CANT_READ_CHARSET), cs_name, cs_dir_name);
  }
  charsets_dir= save_csdir;
  return mysql->net.last_errno;
}