sql_parse.cc

/* 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; either version 2 of the License, or
   (at your option) any later version.

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

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

#include "mysql_priv.h"
#include "sql_acl.h"
#include "sql_repl.h"
#include "repl_failsafe.h"
#include <m_ctype.h>
#include <myisam.h>
#include <my_dir.h>
#include <assert.h>

#ifdef HAVE_INNOBASE_DB
#include "ha_innodb.h"
#endif

#ifdef HAVE_OPENSSL
/*
  Without SSL the handshake consists of one packet. This packet
  has both client capabilites and scrambled password.
  With SSL the handshake might consist of two packets. If the first
  packet (client capabilities) has CLIENT_SSL flag set, we have to
  switch to SSL and read the second packet. The scrambled password
  is in the second packet and client_capabilites field will be ignored.
  Maybe it is better to accept flags other than CLIENT_SSL from the
  second packet?
*/
#define SSL_HANDSHAKE_SIZE      2
#define NORMAL_HANDSHAKE_SIZE   6
#define MIN_HANDSHAKE_SIZE      2
#else
#define MIN_HANDSHAKE_SIZE      6
#endif /* HAVE_OPENSSL */
#define SCRAMBLE_LENGTH 8

extern int yyparse(void);
extern "C" pthread_mutex_t THR_LOCK_keycache;
#ifdef SOLARIS
extern "C" int gethostname(char *name, int namelen);
#endif

static int check_for_max_user_connections(USER_CONN *uc);
static void decrease_user_connections(USER_CONN *uc);
static bool check_db_used(THD *thd,TABLE_LIST *tables);
static bool check_merge_table_access(THD *thd, char *db, TABLE_LIST *tables);
static void mysql_init_query(THD *thd);
static void remove_escape(char *name);
static void refresh_status(void);
static bool append_file_to_dir(THD *thd, const char **filename_ptr,
			       const char *table_name);
static bool create_total_list(THD *thd, LEX *lex,
			      TABLE_LIST **result, bool skip_first);
static bool check_one_table_access(THD *thd, ulong want_access,
				   TABLE_LIST *table, bool no_errors);


const char *any_db="*any*";	// Special symbol for check_access

const char *command_name[]={
  "Sleep", "Quit", "Init DB", "Query", "Field List", "Create DB",
  "Drop DB", "Refresh", "Shutdown", "Statistics", "Processlist",
  "Connect","Kill","Debug","Ping","Time","Delayed_insert","Change user",
  "Binlog Dump","Table Dump",  "Connect Out", "Register Slave",
  "Error"					// Last command number
};

bool volatile abort_slave = 0;

#ifdef __WIN__
static void  test_signal(int sig_ptr)
{
#if !defined( DBUG_OFF)
  MessageBox(NULL,"Test signal","DBUG",MB_OK);
#endif
#if defined(OS2)
  fprintf(stderr, "Test signal %d\n", sig_ptr);
  fflush(stderr);
#endif
}
static void init_signals(void)
{
  int signals[7] = {SIGINT,SIGILL,SIGFPE,SIGSEGV,SIGTERM,SIGBREAK,SIGABRT } ;
  for (int i=0 ; i < 7 ; i++)
    signal( signals[i], test_signal) ;
}
#endif

static void unlock_locked_tables(THD *thd)
{
  if (thd->locked_tables)
  {
    thd->lock=thd->locked_tables;
    thd->locked_tables=0;			// Will be automaticly closed
    close_thread_tables(thd);			// Free tables
  }
}


static bool end_active_trans(THD *thd)
{
  int error=0;
  if (thd->options & (OPTION_NOT_AUTOCOMMIT | OPTION_BEGIN |
		      OPTION_TABLE_LOCK))
  {
    thd->options&= ~(ulong) (OPTION_BEGIN | OPTION_STATUS_NO_TRANS_UPDATE);
    thd->server_status&= ~SERVER_STATUS_IN_TRANS;
    if (ha_commit(thd))
      error=1;
  }
  return error;
}


inline bool all_tables_not_ok(THD *thd, TABLE_LIST *tables)
{
  return (table_rules_on && tables && !tables_ok(thd,tables) &&
          ((thd->lex.sql_command != SQLCOM_DELETE_MULTI) ||
           !tables_ok(thd,(TABLE_LIST *)thd->lex.auxilliary_table_list.first)));
}


static HASH hash_user_connections;
extern  pthread_mutex_t LOCK_user_conn;

static int get_or_create_user_conn(THD *thd, const char *user,
				   const char *host,
				   USER_RESOURCES *mqh) 
{
  int return_val=0;
  uint temp_len, user_len, host_len;
  char temp_user[USERNAME_LENGTH+HOSTNAME_LENGTH+2];
  struct  user_conn *uc;

  DBUG_ASSERT(user != 0);
  DBUG_ASSERT(host != 0);

  user_len=strlen(user);
  host_len=strlen(host);
  temp_len= (strmov(strmov(temp_user, user)+1, host) - temp_user)+1;
  (void) pthread_mutex_lock(&LOCK_user_conn);
  if (!(uc = (struct  user_conn *) hash_search(&hash_user_connections,
					       (byte*) temp_user, temp_len)))
  {
    /* First connection for user; Create a user connection object */
    if (!(uc= ((struct user_conn*)
	       my_malloc(sizeof(struct user_conn) + temp_len+1,
			 MYF(MY_WME)))))
    {
      send_error(&current_thd->net, 0, NullS);	// Out of memory
      return_val=1;
      goto end;
    }
    uc->user=(char*) (uc+1);
    memcpy(uc->user,temp_user,temp_len+1);
    uc->user_len= user_len;
    uc->host=uc->user + uc->user_len +  1;
    uc->len = temp_len;
    uc->connections = 0;
    uc->questions=uc->updates=uc->conn_per_hour=0;
    uc->user_resources=*mqh;
    if (max_user_connections && mqh->connections > max_user_connections) 
      uc->user_resources.connections = max_user_connections;
    uc->intime=thd->thr_create_time;
    if (hash_insert(&hash_user_connections, (byte*) uc))
    {
      my_free((char*) uc,0);
      send_error(&current_thd->net, 0, NullS);	// Out of memory
      return_val=1;
      goto end;
    }
  }
  thd->user_connect=uc;
  uc->connections++;
end:
  (void) pthread_mutex_unlock(&LOCK_user_conn);
  return return_val;
 
}


/*
  Check if user is ok
  Updates:
  thd->{user,master_access,priv_user,priv_host,db,db_access}
*/

static bool check_user(THD *thd,enum_server_command command, const char *user,
		       const char *passwd, const char *db, bool check_count)
{
  NET *net= &thd->net;
  thd->db=0;
  thd->db_length=0;
  USER_RESOURCES ur;
  char tmp_passwd[SCRAMBLE_LENGTH + 1];

  if (passwd[0] && strlen(passwd) != SCRAMBLE_LENGTH)
    return 1;
  /*
    Move password to temporary buffer as it may be stored in communication
    buffer
  */
  strmov(tmp_passwd, passwd);
  passwd= tmp_passwd;				// Use local copy

  if (!(thd->user = my_strdup(user, MYF(0))))
  {
    send_error(net,ER_OUT_OF_RESOURCES);
    return 1;
  }
  thd->master_access=acl_getroot(thd, thd->host, thd->ip, thd->user,
				 passwd, thd->scramble,
                                 &thd->priv_user, thd->priv_host,
				 protocol_version == 9 ||
				 !(thd->client_capabilities &
				   CLIENT_LONG_PASSWORD),&ur);
  DBUG_PRINT("info",
	     ("Capabilities: %d  packet_length: %ld  Host: '%s'  Login user: '%s'  Priv_user: '%s'  Using password: %s  Access: %u  db: '%s'",
	      thd->client_capabilities, thd->max_client_packet_length,
	      thd->host_or_ip, thd->user, thd->priv_user,
	      passwd[0] ? "yes": "no",
	      thd->master_access, thd->db ? thd->db : "*none*"));
  if (thd->master_access & NO_ACCESS)
  {
    net_printf(net, ER_ACCESS_DENIED_ERROR,
	       thd->user,
	       thd->host_or_ip,
	       passwd[0] ? ER(ER_YES) : ER(ER_NO));
    mysql_log.write(thd,COM_CONNECT,ER(ER_ACCESS_DENIED_ERROR),
		    thd->user,
		    thd->host_or_ip,
		    passwd[0] ? ER(ER_YES) : ER(ER_NO));
    return(1);					// Error already given
  }
  if (check_count)
  {
    VOID(pthread_mutex_lock(&LOCK_thread_count));
    bool tmp=(thread_count - delayed_insert_threads >= max_connections &&
	      !(thd->master_access & SUPER_ACL));
    VOID(pthread_mutex_unlock(&LOCK_thread_count));
    if (tmp)
    {						// Too many connections
      send_error(net, ER_CON_COUNT_ERROR);
      return(1);
    }
  }
  mysql_log.write(thd,command,
		  (thd->priv_user == thd->user ?
		   (char*) "%s@%s on %s" :
		   (char*) "%s@%s as anonymous on %s"),
		  user,
		  thd->host_or_ip,
		  db ? db : (char*) "");
  thd->db_access=0;
  /* Don't allow user to connect if he has done too many queries */
  if ((ur.questions || ur.updates || ur.connections || max_user_connections) &&
      get_or_create_user_conn(thd,user,thd->host_or_ip,&ur))
    return -1;
  if (thd->user_connect && (thd->user_connect->user_resources.connections ||
			    max_user_connections) &&
      check_for_max_user_connections(thd->user_connect))
    return -1;
  if (db && db[0])
  {
    bool error=test(mysql_change_db(thd,db));
    if (error && thd->user_connect)
      decrease_user_connections(thd->user_connect);
    return error;
  }
  send_ok(net);                                 // Ready to handle questions
  thd->password= test(passwd[0]);		// Remember for error messages
  return 0;					// ok
}


/*
  Check for maximum allowable user connections, if the mysqld server is
  started with corresponding variable that is greater then 0.
*/

extern "C" byte *get_key_conn(user_conn *buff, uint *length,
			      my_bool not_used __attribute__((unused)))
{
  *length=buff->len;
  return (byte*) buff->user;
}

extern "C" void free_user(struct user_conn *uc)
{
  my_free((char*) uc,MYF(0));
}

void init_max_user_conn(void) 
{
  (void) hash_init(&hash_user_connections,max_connections,0,0,
		   (hash_get_key) get_key_conn, (hash_free_key) free_user,
		   0);
}


static int check_for_max_user_connections(USER_CONN *uc)
{
  int error=0;
  DBUG_ENTER("check_for_max_user_connections");

  (void) pthread_mutex_lock(&LOCK_user_conn);
  if (max_user_connections &&
      max_user_connections < uc->connections)
  {
    net_printf(&(current_thd->net),ER_TOO_MANY_USER_CONNECTIONS, uc->user);
    error=1;
    goto end;
  }
  if (uc->user_resources.connections &&
      uc->user_resources.connections <= uc->conn_per_hour)
  {
    net_printf(&current_thd->net, ER_USER_LIMIT_REACHED, uc->user,
	       "max_connections",
	       (long) uc->user_resources.connections);
    error=1;
    goto end;
  }
  uc->conn_per_hour++;
end:
  if (error)
    uc->connections--; // no need for decrease_user_connections() here
  (void) pthread_mutex_unlock(&LOCK_user_conn);
  DBUG_RETURN(error);
}


static void decrease_user_connections(USER_CONN *uc)
{
  DBUG_ENTER("decrease_user_connections");
  (void) pthread_mutex_lock(&LOCK_user_conn);
  DBUG_ASSERT(uc->connections);
  if (!--uc->connections && !mqh_used)
  {
    /* Last connection for user; Delete it */
    (void) hash_delete(&hash_user_connections,(byte*) uc);
  }
  (void) pthread_mutex_unlock(&LOCK_user_conn);
  DBUG_VOID_RETURN;
}


void free_max_user_conn(void)
{
  hash_free(&hash_user_connections);
}


/*
  Mark all commands that somehow changes a table
  This is used to check number of updates / hour
*/

char  uc_update_queries[SQLCOM_END];

void init_update_queries(void)
{
  uc_update_queries[SQLCOM_CREATE_TABLE]=1;
  uc_update_queries[SQLCOM_CREATE_INDEX]=1;
  uc_update_queries[SQLCOM_ALTER_TABLE]=1;
  uc_update_queries[SQLCOM_UPDATE]=1;
  uc_update_queries[SQLCOM_INSERT]=1;
  uc_update_queries[SQLCOM_INSERT_SELECT]=1;
  uc_update_queries[SQLCOM_DELETE]=1;
  uc_update_queries[SQLCOM_TRUNCATE]=1;
  uc_update_queries[SQLCOM_DROP_TABLE]=1;
  uc_update_queries[SQLCOM_LOAD]=1;
  uc_update_queries[SQLCOM_CREATE_DB]=1;
  uc_update_queries[SQLCOM_DROP_DB]=1;
  uc_update_queries[SQLCOM_REPLACE]=1;
  uc_update_queries[SQLCOM_REPLACE_SELECT]=1;
  uc_update_queries[SQLCOM_RENAME_TABLE]=1;
  uc_update_queries[SQLCOM_BACKUP_TABLE]=1;
  uc_update_queries[SQLCOM_RESTORE_TABLE]=1;
  uc_update_queries[SQLCOM_DELETE_MULTI]=1;
  uc_update_queries[SQLCOM_DROP_INDEX]=1;
  uc_update_queries[SQLCOM_MULTI_UPDATE]=1;
}


/*
  Check if maximum queries per hour limit has been reached
  returns 0 if OK.

  In theory we would need a mutex in the USER_CONN structure for this to
  be 100 % safe, but as the worst scenario is that we would miss counting
  a couple of queries, this isn't critical.
*/


static bool check_mqh(THD *thd, uint check_command)
{
  bool error=0;
  time_t check_time = thd->start_time ?  thd->start_time : time(NULL);
  USER_CONN *uc=thd->user_connect;
  DBUG_ENTER("check_mqh");
  DBUG_ASSERT(uc != 0);

  /* If more than a hour since last check, reset resource checking */
  if (check_time  - uc->intime >= 3600)
  {
    (void) pthread_mutex_lock(&LOCK_user_conn);
    uc->questions=1;
    uc->updates=0;
    uc->conn_per_hour=0;
    uc->intime=check_time;
    (void) pthread_mutex_unlock(&LOCK_user_conn);
  }
  /* Check that we have not done too many questions / hour */
  if (uc->user_resources.questions &&
      uc->questions++ >= uc->user_resources.questions)
  {
    net_printf(&thd->net, ER_USER_LIMIT_REACHED, uc->user, "max_questions",
	       (long) uc->user_resources.questions);
    error=1;
    goto end;
  }
  if (check_command < (uint) SQLCOM_END)
  {
    /* Check that we have not done too many updates / hour */
    if (uc->user_resources.updates && uc_update_queries[check_command] &&
	uc->updates++ >= uc->user_resources.updates)
    {
      net_printf(&thd->net, ER_USER_LIMIT_REACHED, uc->user, "max_updates",
		 (long) uc->user_resources.updates);
      error=1;
      goto end;
    }
  }
end:
  DBUG_RETURN(error);
}


static void reset_mqh(THD *thd, LEX_USER *lu, bool get_them= 0)
{

  (void) pthread_mutex_lock(&LOCK_user_conn);
  if (lu)  // for GRANT 
  {
    USER_CONN *uc;
    uint temp_len=lu->user.length+lu->host.length+2;
    char temp_user[USERNAME_LENGTH+HOSTNAME_LENGTH+2];

    memcpy(temp_user,lu->user.str,lu->user.length);
    memcpy(temp_user+lu->user.length+1,lu->host.str,lu->host.length);
    temp_user[lu->user.length]='\0'; temp_user[temp_len-1]=0;
    if ((uc = (struct  user_conn *) hash_search(&hash_user_connections,
						(byte*) temp_user, temp_len)))
    {
      uc->questions=0;
      get_mqh(temp_user,&temp_user[lu->user.length+1],uc);
      uc->updates=0;
      uc->conn_per_hour=0;
    }
  }
  else // for FLUSH PRIVILEGES and FLUSH USER_RESOURCES
  {
    for (uint idx=0;idx < hash_user_connections.records; idx++)
    {
      USER_CONN *uc=(struct user_conn *) hash_element(&hash_user_connections, idx);
      if (get_them)
	get_mqh(uc->user,uc->host,uc);
      uc->questions=0;
      uc->updates=0;
      uc->conn_per_hour=0;
    }
  }
  (void) pthread_mutex_unlock(&LOCK_user_conn);
}


/*
  Check connnetion and get priviliges
  Returns 0 on ok, -1 < if error is given > 0 on error.
*/

static int
check_connections(THD *thd)
{
  uint connect_errors=0;
  NET *net= &thd->net;
  /* Store the connection details */
  DBUG_PRINT("info", (("check_connections called by thread %d"),
	     thd->thread_id));
  DBUG_PRINT("info",("New connection received on %s",
			vio_description(net->vio)));
  if (!thd->host)                           // If TCP/IP connection
  {
    char ip[30];

    if (vio_peer_addr(net->vio, ip, &thd->peer_port))
      return (ER_BAD_HOST_ERROR);
    if (!(thd->ip = my_strdup(ip,MYF(0))))
      return (ER_OUT_OF_RESOURCES);
    thd->host_or_ip=thd->ip;
#if !defined(HAVE_SYS_UN_H) || defined(HAVE_mit_thread)
    /* Fast local hostname resolve for Win32 */
    if (!strcmp(thd->ip,"127.0.0.1"))
    {
      thd->host= (char*) localhost;
      thd->host_or_ip= localhost;
    }
    else
#endif
    if (!(specialflag & SPECIAL_NO_RESOLVE))
    {
      vio_in_addr(net->vio,&thd->remote.sin_addr);
      thd->host=ip_to_hostname(&thd->remote.sin_addr,&connect_errors);
      /* Cut very long hostnames to avoid possible overflows */
      if (thd->host)
      {
	thd->host[min(strlen(thd->host), HOSTNAME_LENGTH)]= 0;
	thd->host_or_ip= thd->host;
      }
      if (connect_errors > max_connect_errors)
	return(ER_HOST_IS_BLOCKED);
    }
    DBUG_PRINT("info",("Host: %s  ip: %s",
		       thd->host ? thd->host : "unknown host",
		       thd->ip ? thd->ip : "unknown ip"));
    if (acl_check_host(thd->host,thd->ip))
      return(ER_HOST_NOT_PRIVILEGED);
  }
  else /* Hostname given means that the connection was on a socket */
  {
    DBUG_PRINT("info",("Host: %s",thd->host));
    thd->host_or_ip= thd->host;
    thd->ip= 0;
    bzero((char*) &thd->remote,sizeof(struct sockaddr));
  }
  vio_keepalive(net->vio, TRUE);

  ulong pkt_len=0;
  {
    /* buff[] needs to big enough to hold the server_version variable */
    char buff[SERVER_VERSION_LENGTH + SCRAMBLE_LENGTH+32],*end;
    int client_flags = CLIENT_LONG_FLAG | CLIENT_CONNECT_WITH_DB;

    if (opt_using_transactions)
      client_flags|=CLIENT_TRANSACTIONS;
#ifdef HAVE_COMPRESS
    client_flags |= CLIENT_COMPRESS;
#endif /* HAVE_COMPRESS */
#ifdef HAVE_OPENSSL
    if (ssl_acceptor_fd)
      client_flags |= CLIENT_SSL;       /* Wow, SSL is avalaible! */
#endif /* HAVE_OPENSSL */

    end=strnmov(buff,server_version,SERVER_VERSION_LENGTH)+1;
    int4store((uchar*) end,thd->thread_id);
    end+=4;
    memcpy(end,thd->scramble,SCRAMBLE_LENGTH+1);
    end+=SCRAMBLE_LENGTH +1;
    int2store(end,client_flags);
    end[2]=(char) MY_CHARSET_CURRENT;
    int2store(end+3,thd->server_status);
    bzero(end+5,13);
    end+=18;
    if (net_write_command(net,(uchar) protocol_version, buff,
			  (uint) (end-buff)) ||
       (pkt_len= my_net_read(net)) == packet_error ||
	pkt_len < MIN_HANDSHAKE_SIZE)
    {
      inc_host_errors(&thd->remote.sin_addr);
      return(ER_HANDSHAKE_ERROR);
    }
  }
#ifdef _CUSTOMCONFIG_
#include "_cust_sql_parse.h"
#endif
  if (connect_errors)
    reset_host_errors(&thd->remote.sin_addr);
  if (thd->packet.alloc(thd->variables.net_buffer_length))
    return(ER_OUT_OF_RESOURCES);

  thd->client_capabilities=uint2korr(net->read_pos);
  if (thd->client_capabilities & CLIENT_IGNORE_SPACE)
    thd->sql_mode|= MODE_IGNORE_SPACE;
#ifdef HAVE_OPENSSL
  DBUG_PRINT("info", ("client capabilities: %d", thd->client_capabilities));
  if (thd->client_capabilities & CLIENT_SSL)
  {
    /* Do the SSL layering. */
    if (!ssl_acceptor_fd)
    {
      inc_host_errors(&thd->remote.sin_addr);
      return(ER_HANDSHAKE_ERROR);
    }
    DBUG_PRINT("info", ("IO layer change in progress..."));
    if (sslaccept(ssl_acceptor_fd, net->vio, thd->variables.net_wait_timeout))
    {
      DBUG_PRINT("error", ("Failed to read user information (pkt_len= %lu)",
			   pkt_len));
      inc_host_errors(&thd->remote.sin_addr);
      return(ER_HANDSHAKE_ERROR);    
    }
    DBUG_PRINT("info", ("Reading user information over SSL layer"));
    if ((pkt_len=my_net_read(net)) == packet_error ||
	pkt_len < NORMAL_HANDSHAKE_SIZE)
    {
      DBUG_PRINT("error", ("Failed to read user information (pkt_len= %lu)",
			   pkt_len));
      inc_host_errors(&thd->remote.sin_addr);
      return(ER_HANDSHAKE_ERROR);
    }
  }
  else
  {
    DBUG_PRINT("info", ("Leaving IO layer intact"));
    if (pkt_len < NORMAL_HANDSHAKE_SIZE)
    {
      inc_host_errors(&thd->remote.sin_addr);
      return ER_HANDSHAKE_ERROR;
    }
  }
#endif

  thd->max_client_packet_length=uint3korr(net->read_pos+2);
  char *user=   (char*) net->read_pos+5;
  char *passwd= strend(user)+1;
  char *db=0;
  if (thd->client_capabilities & CLIENT_CONNECT_WITH_DB)
    db=strend(passwd)+1;
  if (thd->client_capabilities & CLIENT_INTERACTIVE)
    thd->variables.net_wait_timeout= thd->variables.net_interactive_timeout;
  if ((thd->client_capabilities & CLIENT_TRANSACTIONS) &&
      opt_using_transactions)
    thd->net.return_status= &thd->server_status;
  net->read_timeout=(uint) thd->variables.net_read_timeout;
  if (check_user(thd,COM_CONNECT, user, passwd, db, 1))
    return (-1);
  return 0;
}


pthread_handler_decl(handle_one_connection,arg)
{
  THD *thd=(THD*) arg;
  uint launch_time  =
    (uint) ((thd->thr_create_time = time(NULL)) - thd->connect_time);
  if (launch_time >= slow_launch_time)
    statistic_increment(slow_launch_threads,&LOCK_status );

  pthread_detach_this_thread();

#if !defined( __WIN__) && !defined(OS2)	// Win32 calls this in pthread_create
  // The following calls needs to be done before we call DBUG_ macros
  if (!(test_flags & TEST_NO_THREADS) & my_thread_init())
  {
    close_connection(&thd->net,ER_OUT_OF_RESOURCES);
    statistic_increment(aborted_connects,&LOCK_status);
    end_thread(thd,0);
    return 0;
  }
#endif

  /*
    handle_one_connection() is the only way a thread would start
    and would always be on top of the stack, therefore, the thread
    stack always starts at the address of the first local variable
    of handle_one_connection, which is thd. We need to know the
    start of the stack so that we could check for stack overruns.
  */
  DBUG_PRINT("info", ("handle_one_connection called by thread %d\n",
		      thd->thread_id));
  // now that we've called my_thread_init(), it is safe to call DBUG_*

#if defined(__WIN__)
  init_signals();				// IRENA; testing ?
#elif !defined(OS2) && !defined(__NETWARE__)
  sigset_t set;
  VOID(sigemptyset(&set));			// Get mask in use
  VOID(pthread_sigmask(SIG_UNBLOCK,&set,&thd->block_signals));
#endif
  if (thd->store_globals())
  {
    close_connection(&thd->net,ER_OUT_OF_RESOURCES);
    statistic_increment(aborted_connects,&LOCK_status);
    end_thread(thd,0);
    return 0;
  }

  do
  {
    int error;
    NET *net= &thd->net;
    thd->thread_stack= (char*) &thd;

    if ((error=check_connections(thd)))
    {						// Wrong permissions
      if (error > 0)
	net_printf(net,error,thd->host_or_ip);
#ifdef __NT__
      if (vio_type(net->vio) == VIO_TYPE_NAMEDPIPE)
	sleep(1);				/* must wait after eof() */
#endif
      statistic_increment(aborted_connects,&LOCK_status);
      goto end_thread;
    }
#ifdef __NETWARE__
    netware_reg_user(thd->ip, thd->user, "MySQL");
#endif
    if (thd->variables.max_join_size == HA_POS_ERROR)
      thd->options |= OPTION_BIG_SELECTS;
    if (thd->client_capabilities & CLIENT_COMPRESS)
      net->compress=1;				// Use compression

    thd->proc_info=0;				// Remove 'login'
    thd->command=COM_SLEEP;
    thd->version=refresh_version;
    thd->set_time();
    init_sql_alloc(&thd->mem_root, thd->variables.query_alloc_block_size,
		   thd->variables.query_prealloc_size);
    init_sql_alloc(&thd->transaction.mem_root,
		   thd->variables.trans_alloc_block_size,
		   thd->variables.trans_prealloc_size);

    while (!net->error && net->vio != 0 && !thd->killed)
    {
      if (do_command(thd))
	break;
    }
    if (thd->user_connect)
      decrease_user_connections(thd->user_connect);
    free_root(&thd->mem_root,MYF(0));
    if (net->error && net->vio != 0)
    {
      if (!thd->killed && thd->variables.log_warnings > 1)
	sql_print_error(ER(ER_NEW_ABORTING_CONNECTION),
			thd->thread_id,(thd->db ? thd->db : "unconnected"),
			thd->user ? thd->user : "unauthenticated",
			thd->host_or_ip,
			(net->last_errno ? ER(net->last_errno) :
			 ER(ER_UNKNOWN_ERROR)));
      send_error(net,net->last_errno,NullS);
      statistic_increment(aborted_threads,&LOCK_status);
    }
    else if (thd->killed)
    {
      statistic_increment(aborted_threads,&LOCK_status);
    }
    
end_thread:
    close_connection(net);
    end_thread(thd,1);
    /*
      If end_thread returns, we are either running with --one-thread
      or this thread has been schedule to handle the next query
    */
    thd= current_thd;
  } while (!(test_flags & TEST_NO_THREADS));
  /* The following is only executed if we are not using --one-thread */
  return(0);					/* purecov: deadcode */
}

/*
  Execute commands from bootstrap_file.
  Used when creating the initial grant tables
*/

extern "C" pthread_handler_decl(handle_bootstrap,arg)
{
  THD *thd=(THD*) arg;
  FILE *file=bootstrap_file;
  char *buff;

  /* The following must be called before DBUG_ENTER */
  if (my_thread_init() || thd->store_globals())
  {
    close_connection(&thd->net,ER_OUT_OF_RESOURCES);
    thd->fatal_error=1;
    goto end;
  }
  DBUG_ENTER("handle_bootstrap");

  pthread_detach_this_thread();
  thd->thread_stack= (char*) &thd;
#if !defined(__WIN__) && !defined(OS2) && !defined(__NETWARE__)
  sigset_t set;
  VOID(sigemptyset(&set));			// Get mask in use
  VOID(pthread_sigmask(SIG_UNBLOCK,&set,&thd->block_signals));
#endif

  if (thd->variables.max_join_size == HA_POS_ERROR)
    thd->options |= OPTION_BIG_SELECTS;

  thd->proc_info=0;
  thd->version=refresh_version;
  thd->priv_user=thd->user=(char*) my_strdup("boot", MYF(MY_WME));

  buff= (char*) thd->net.buff;
  init_sql_alloc(&thd->mem_root, thd->variables.query_alloc_block_size,
		 thd->variables.query_prealloc_size);
  init_sql_alloc(&thd->transaction.mem_root,
		 thd->variables.trans_alloc_block_size,
		 thd->variables.trans_prealloc_size);
  while (fgets(buff, thd->net.max_packet, file))
  {
    uint length=(uint) strlen(buff);
    while (length && (isspace(buff[length-1]) || buff[length-1] == ';'))
      length--;
    buff[length]=0;
    thd->current_tablenr=0;
    thd->query_length=length;
    thd->query= thd->memdup_w_gap(buff, length+1, thd->db_length+1);
    thd->query[length] = '\0';
    thd->query_id=query_id++;
    if (mqh_used && thd->user_connect && check_mqh(thd, SQLCOM_END))
    {
      thd->net.error = 0;
      close_thread_tables(thd);			// Free tables
      free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
      break;
    }
    mysql_parse(thd,thd->query,length);
    close_thread_tables(thd);			// Free tables
    if (thd->fatal_error)
      break;
    free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
    free_root(&thd->transaction.mem_root,MYF(MY_KEEP_PREALLOC));
  }

  /* thd->fatal_error should be set in case something went wrong */
end:
  (void) pthread_mutex_lock(&LOCK_thread_count);
  thread_count--;
  (void) pthread_mutex_unlock(&LOCK_thread_count);
  (void) pthread_cond_broadcast(&COND_thread_count);
  my_thread_end();
  pthread_exit(0);
  DBUG_RETURN(0);				// Never reached
}


inline void free_items(THD *thd)
{
    /* This works because items are allocated with sql_alloc() */
  for (Item *item=thd->free_list ; item ; item=item->next)
    delete item;
}

int mysql_table_dump(THD* thd, char* db, char* tbl_name, int fd)
{
  TABLE* table;
  TABLE_LIST* table_list;
  int error = 0;
  DBUG_ENTER("mysql_table_dump");
  db = (db && db[0]) ? db : thd->db;
  if (!(table_list = (TABLE_LIST*) thd->calloc(sizeof(TABLE_LIST))))
    DBUG_RETURN(1); // out of memory
  table_list->db = db;
  table_list->real_name = table_list->alias = tbl_name;
  table_list->lock_type = TL_READ_NO_INSERT;
  table_list->next = 0;

  if (!db || check_db_name(db))
  {
    net_printf(&thd->net,ER_WRONG_DB_NAME, db ? db : "NULL");
    goto err;
  }
  if (lower_case_table_names)
    casedn_str(tbl_name);
  remove_escape(tbl_name);

  if (!(table=open_ltable(thd, table_list, TL_READ_NO_INSERT)))
    DBUG_RETURN(1);

  if (check_one_table_access(thd, SELECT_ACL, table_list, 0))
    goto err;
  thd->free_list = 0;
  thd->query_length=(uint) strlen(tbl_name);
  thd->query = tbl_name;
  if ((error = mysqld_dump_create_info(thd, table, -1)))
  {
    my_error(ER_GET_ERRNO, MYF(0));
    goto err;
  }
  net_flush(&thd->net);
  if ((error= table->file->dump(thd,fd)))
    my_error(ER_GET_ERRNO, MYF(0));

err:
  close_thread_tables(thd);
  DBUG_RETURN(error);
}


	/* Execute one command from socket (query or simple command) */

bool do_command(THD *thd)
{
  char *packet;
  uint old_timeout;
  ulong packet_length;
  NET *net;
  enum enum_server_command command;
  DBUG_ENTER("do_command");

  net= &thd->net;
  thd->current_tablenr=0;

  packet=0;
  old_timeout=net->read_timeout;
  // Wait max for 8 hours
  net->read_timeout=(uint) thd->variables.net_wait_timeout;
  net->last_error[0]=0;				// Clear error message
  net->last_errno=0;

  net_new_transaction(net);
  if ((packet_length=my_net_read(net)) == packet_error)
  {
    DBUG_PRINT("info",("Got error %d reading command from socket %s",
		       net->error,
		       vio_description(net->vio)));
    /* Check if we can continue without closing the connection */
    if (net->error != 3)
    {
      statistic_increment(aborted_threads,&LOCK_status);
      DBUG_RETURN(TRUE);			// We have to close it.
    }
    send_error(net,net->last_errno,NullS);
    net->error= 0;
    DBUG_RETURN(FALSE);
  }
  else
  {
    packet=(char*) net->read_pos;
    command = (enum enum_server_command) (uchar) packet[0];
    if (command >= COM_END)
      command= COM_END;				// Wrong command
    DBUG_PRINT("info",("Command on %s = %d (%s)",
		       vio_description(net->vio), command,
		       command_name[command]));
  }
  net->read_timeout=old_timeout;		// restore it
  DBUG_RETURN(dispatch_command(command,thd, packet+1, (uint) packet_length));
}


bool dispatch_command(enum enum_server_command command, THD *thd,
		      char* packet, uint packet_length)
{
  NET *net= &thd->net;
  bool	error=0;
  /*
    Commands which will always take a long time should be marked with
    this so that they will not get logged to the slow query log
  */
  bool slow_command=FALSE;
  DBUG_ENTER("dispatch_command");

  thd->command=command;
  thd->set_time();
  VOID(pthread_mutex_lock(&LOCK_thread_count));
  thd->query_id=query_id;
  if (command != COM_STATISTICS && command != COM_PING)
    query_id++;
  thread_running++;
  VOID(pthread_mutex_unlock(&LOCK_thread_count));

  thd->lex.select_lex.options=0;		// We store status here
  switch (command) {
  case COM_INIT_DB:
    statistic_increment(com_stat[SQLCOM_CHANGE_DB],&LOCK_status);
    if (!mysql_change_db(thd,packet))
      mysql_log.write(thd,command,"%s",thd->db);
    break;
  case COM_REGISTER_SLAVE:
  {
    if (!register_slave(thd, (uchar*)packet, packet_length))
      send_ok(&thd->net);
    break;
  }
  case COM_TABLE_DUMP:
    {
      statistic_increment(com_other, &LOCK_status);
      slow_command = TRUE;
      uint db_len = *(uchar*)packet;
      uint tbl_len = *(uchar*)(packet + db_len + 1);
      char* db = thd->alloc(db_len + tbl_len + 2);
      memcpy(db, packet + 1, db_len);
      char* tbl_name = db + db_len;
      *tbl_name++ = 0;
      memcpy(tbl_name, packet + db_len + 2, tbl_len);
      tbl_name[tbl_len] = 0;
      if (mysql_table_dump(thd, db, tbl_name, -1))
	send_error(&thd->net); // dump to NET
      break;
    }
  case COM_CHANGE_USER:
  {
    thd->change_user();
    clear_error_message(thd);			// If errors from rollback

    statistic_increment(com_other,&LOCK_status);
    char *user=   (char*) packet;
    char *passwd= strend(user)+1;
    char *db=     strend(passwd)+1;

    /* Save user and privileges */
    uint save_master_access=thd->master_access;
    uint save_db_access=    thd->db_access;
    uint save_db_length=    thd->db_length;
    char *save_user=	    thd->user;
    char *save_priv_user=   thd->priv_user;
    char *save_db=	    thd->db;
    USER_CONN *save_user_connect= thd->user_connect;

    if ((uint) ((uchar*) db - net->read_pos) > packet_length)
    {						// Check if protocol is ok
      send_error(net, ER_UNKNOWN_COM_ERROR);
      break;
    }

    /* Clear variables that are allocated */
    thd->user= 0;
    thd->user_connect= 0;
    if (check_user(thd, COM_CHANGE_USER, user, passwd, db, 0))
    {						// Restore old user
      x_free(thd->user);
      thd->master_access=save_master_access;
      thd->db_access=save_db_access;
      thd->db=save_db;
      thd->db_length=save_db_length;
      thd->user=save_user;
      thd->priv_user=save_priv_user;
      thd->user_connect= save_user_connect;
      break;
    }
    if (save_user_connect)
      decrease_user_connections(save_user_connect);
    x_free((gptr) save_db);
    x_free((gptr) save_user);
    break;
  }

  case COM_QUERY:
  {
    packet_length--;				// Remove end null
    /* Remove garage at start and end of query */
    while (isspace(packet[0]) && packet_length > 0)
    {
      packet++;
      packet_length--;
    }
    char *pos=packet+packet_length;		// Point at end null
    while (packet_length > 0 && (pos[-1] == ';' || isspace(pos[-1])))
    {
      pos--;
      packet_length--;
    }
    /* We must allocate some extra memory for query cache */
    thd->query_length= 0;                       // Extra safety: Avoid races
    if (!(thd->query= (char*) thd->memdup_w_gap((gptr) (packet),
						packet_length,
						thd->db_length+2+
						sizeof(ha_rows))))
      break;
    thd->query[packet_length]=0;
    thd->packet.shrink(thd->variables.net_buffer_length);// Reclaim some memory
    if (!(specialflag & SPECIAL_NO_PRIOR))
      my_pthread_setprio(pthread_self(),QUERY_PRIOR);
    mysql_log.write(thd,command,"%s",thd->query);
    DBUG_PRINT("query",("%-.4096s",thd->query));
    /* thd->query_length is set by mysql_parse() */
    mysql_parse(thd,thd->query,packet_length);
    if (!(specialflag & SPECIAL_NO_PRIOR))
      my_pthread_setprio(pthread_self(),WAIT_PRIOR);
    DBUG_PRINT("info",("query ready"));
    break;
  }
  case COM_FIELD_LIST:				// This isn't actually needed
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    break;
#else
  {
    char *fields;
    TABLE_LIST table_list;
    statistic_increment(com_stat[SQLCOM_SHOW_FIELDS],&LOCK_status);
    bzero((char*) &table_list,sizeof(table_list));
    if (!(table_list.db=thd->db))
    {
      send_error(net,ER_NO_DB_ERROR);
      break;
    }
    thd->free_list=0;
    table_list.alias= table_list.real_name= thd->strdup(packet);
    packet=strend(packet)+1;
    // command not cachable => no gap for data base name
    if (!(thd->query=fields=thd->memdup(packet,thd->query_length+1)))
      break;
    mysql_log.write(thd,command,"%s %s",table_list.real_name,fields);
    if (lower_case_table_names)
      casedn_str(table_list.real_name);
    remove_escape(table_list.real_name);	// This can't have wildcards

    if (check_access(thd,SELECT_ACL,table_list.db,&table_list.grant.privilege))
      break;
    if (grant_option && check_grant(thd,SELECT_ACL,&table_list,2))
      break;
    mysqld_list_fields(thd,&table_list,fields);
    free_items(thd);
    break;
  }
#endif
  case COM_QUIT:
    /* We don't calculate statistics for this command */
    mysql_log.write(thd,command,NullS);
    net->error=0;				// Don't give 'abort' message
    error=TRUE;					// End server
    break;

  case COM_CREATE_DB:				// QQ: To be removed
    {
      char *db=thd->strdup(packet), *alias;

      statistic_increment(com_stat[SQLCOM_CREATE_DB],&LOCK_status);
      // null test to handle EOM
      if (!db || !(alias= thd->strdup(db)) || check_db_name(db))
      {
	net_printf(&thd->net,ER_WRONG_DB_NAME, db ? db : "NULL");
	break;
      }
      if (check_access(thd,CREATE_ACL,db,0,1))
	break;
      mysql_log.write(thd,command,packet);
      mysql_create_db(thd,(lower_case_table_names == 2 ? alias : db),0,0);
      break;
    }
  case COM_DROP_DB:				// QQ: To be removed
    {
      statistic_increment(com_stat[SQLCOM_DROP_DB],&LOCK_status);
      char *db=thd->strdup(packet), *alias;
      // null test to handle EOM
      if (!db || !(alias= thd->strdup(db)) || check_db_name(db))
      {
	net_printf(&thd->net,ER_WRONG_DB_NAME, db ? db : "NULL");
	break;
      }
      if (check_access(thd,DROP_ACL,db,0,1))
	break;
      if (thd->locked_tables || thd->active_transaction())
      {
	send_error(&thd->net,ER_LOCK_OR_ACTIVE_TRANSACTION);
	break;
      }
      mysql_log.write(thd,command,db);
      mysql_rm_db(thd, (lower_case_table_names == 2 ? alias : db), 0, 0);
      break;
    }
  case COM_BINLOG_DUMP:
    {
      statistic_increment(com_other,&LOCK_status);
      slow_command = TRUE;
      if (check_global_access(thd, REPL_SLAVE_ACL))
	break;
      mysql_log.write(thd,command, 0);

      ulong pos;
      ushort flags;
      uint32 slave_server_id;
      /* TODO: The following has to be changed to an 8 byte integer */
      pos = uint4korr(packet);
      flags = uint2korr(packet + 4);
      thd->server_id=0; /* avoid suicide */
      if ((slave_server_id= uint4korr(packet+6))) // mysqlbinlog.server_id==0
	kill_zombie_dump_threads(slave_server_id);
      thd->server_id = slave_server_id;
      mysql_binlog_send(thd, thd->strdup(packet + 10), (my_off_t) pos, flags);
      unregister_slave(thd,1,1);
      // fake COM_QUIT -- if we get here, the thread needs to terminate
      error = TRUE;
      net->error = 0;
      break;
    }
  case COM_REFRESH:
    {
      statistic_increment(com_stat[SQLCOM_FLUSH],&LOCK_status);
      ulong options= (ulong) (uchar) packet[0];
      if (check_global_access(thd,RELOAD_ACL))
	break;
      mysql_log.write(thd,command,NullS);
      /* error sending is deferred to reload_acl_and_cache */
      reload_acl_and_cache(thd, options, (TABLE_LIST*) 0) ;
      break;
    }
  case COM_SHUTDOWN:
    statistic_increment(com_other,&LOCK_status);
    if (check_global_access(thd,SHUTDOWN_ACL))
      break; /* purecov: inspected */
    DBUG_PRINT("quit",("Got shutdown command"));
    mysql_log.write(thd,command,NullS);
    send_eof(net);
#ifdef __WIN__
    sleep(1);					// must wait after eof()
#endif
#ifndef OS2
    send_eof(net);				// This is for 'quit request'
#endif
    close_connection(net);
    close_thread_tables(thd);			// Free before kill
    free_root(&thd->mem_root,MYF(0));
    free_root(&thd->transaction.mem_root,MYF(0));
    kill_mysql();
    error=TRUE;
    break;

  case COM_STATISTICS:
  {
    mysql_log.write(thd,command,NullS);
    statistic_increment(com_stat[SQLCOM_SHOW_STATUS],&LOCK_status);
    char buff[200];
    ulong uptime = (ulong) (thd->start_time - start_time);
    sprintf((char*) buff,
	    "Uptime: %ld  Threads: %d  Questions: %lu  Slow queries: %ld  Opens: %ld  Flush tables: %ld  Open tables: %u  Queries per second avg: %.3f",
	    uptime,
	    (int) thread_count,thd->query_id,long_query_count,
	    opened_tables,refresh_version, cached_tables(),
	    uptime ? (float)thd->query_id/(float)uptime : 0);
#ifdef SAFEMALLOC
    if (sf_malloc_cur_memory)				// Using SAFEMALLOC
      sprintf(strend(buff), "  Memory in use: %ldK  Max memory used: %ldK",
	      (sf_malloc_cur_memory+1023L)/1024L,
	      (sf_malloc_max_memory+1023L)/1024L);
 #endif
    VOID(my_net_write(net, buff,(uint) strlen(buff)));
    VOID(net_flush(net));
    break;
  }
  case COM_PING:
    statistic_increment(com_other,&LOCK_status);
    send_ok(net);				// Tell client we are alive
    break;
  case COM_PROCESS_INFO:
    statistic_increment(com_stat[SQLCOM_SHOW_PROCESSLIST],&LOCK_status);
    if (!thd->priv_user[0] && check_global_access(thd,PROCESS_ACL))
      break;
    mysql_log.write(thd,command,NullS);
    mysqld_list_processes(thd,thd->master_access & PROCESS_ACL ? NullS :
			  thd->priv_user,0);
    break;
  case COM_PROCESS_KILL:
  {
    statistic_increment(com_stat[SQLCOM_KILL],&LOCK_status);
    ulong id=(ulong) uint4korr(packet);
    kill_one_thread(thd,id);
    break;
  }
  case COM_DEBUG:
    statistic_increment(com_other,&LOCK_status);
    if (check_global_access(thd, SUPER_ACL))
      break;					/* purecov: inspected */
    mysql_print_status(thd);
    mysql_log.write(thd,command,NullS);
    send_eof(net);
    break;
  case COM_SLEEP:
  case COM_CONNECT:				// Impossible here
  case COM_TIME:				// Impossible from client
  case COM_DELAYED_INSERT:
  case COM_END:
  default:
    send_error(net, ER_UNKNOWN_COM_ERROR);
    break;
  }
  if (thd->lock || thd->open_tables)
  {
    thd->proc_info="closing tables";
    close_thread_tables(thd);			/* Free tables */
  }

  if (thd->fatal_error)
    send_error(net,0);				// End of memory ?

  time_t start_of_query=thd->start_time;
  thd->end_time();				// Set start time

  /* If not reading from backup and if the query took too long */
  if (!slow_command && !thd->user_time) // do not log 'slow_command' queries
  {
    thd->proc_info="logging slow query";

    if ((ulong) (thd->start_time - thd->time_after_lock) >
	thd->variables.long_query_time ||
	((thd->lex.select_lex.options &
	  (QUERY_NO_INDEX_USED | QUERY_NO_GOOD_INDEX_USED)) &&
	 (specialflag & SPECIAL_LONG_LOG_FORMAT)))
    {
      long_query_count++;
      mysql_slow_log.write(thd, thd->query, thd->query_length, start_of_query);
    }
  }
  thd->proc_info="cleaning up";
  VOID(pthread_mutex_lock(&LOCK_thread_count)); // For process list
  thd->proc_info=0;
  thd->command=COM_SLEEP;
  thd->query=0;
  thd->query_length=0;
  thread_running--;
  VOID(pthread_mutex_unlock(&LOCK_thread_count));
  thd->packet.shrink(thd->variables.net_buffer_length);	// Reclaim some memory
  free_root(&thd->mem_root,MYF(MY_KEEP_PREALLOC));
  DBUG_RETURN(error);
}

/****************************************************************************
** mysql_execute_command
** Execute command saved in thd and current_lex->sql_command
****************************************************************************/

void
mysql_execute_command(void)
{
  int	res=0;
  THD	*thd=current_thd;
  LEX	*lex= &thd->lex;
  TABLE_LIST *tables=(TABLE_LIST*) lex->select_lex.table_list.first;
  SELECT_LEX *select_lex = lex->select;
  DBUG_ENTER("mysql_execute_command");

  if (thd->slave_thread)
  {
    /* 
      Skip if we are in the slave thread, some table rules have been
      given and the table list says the query should not be replicated
    */
    if (all_tables_not_ok(thd,tables))
    {
      /* we warn the slave SQL thread */
      my_error(ER_SLAVE_IGNORED_TABLE, MYF(0));
      DBUG_VOID_RETURN;
    }
#ifndef TO_BE_DELETED
    /*
       This is a workaround to deal with the shortcoming in 3.23.44-3.23.46
       masters in RELEASE_LOCK() logging. We re-write SELECT RELEASE_LOCK()
       as DO RELEASE_LOCK()
    */
    if (lex->sql_command == SQLCOM_SELECT)
    {
      lex->sql_command = SQLCOM_DO;
      lex->insert_list = &select_lex->item_list;
    }
#endif
  }
  
  if (lex->select_lex.next &&
      create_total_list(thd,lex,&tables,
			(lex->sql_command == SQLCOM_CREATE_TABLE)))
    DBUG_VOID_RETURN;
  
  /*
    When option readonly is set deny operations which change tables.
    Except for the replication thread and the 'super' users.
  */
  if (opt_readonly &&
      !(thd->slave_thread || (thd->master_access & SUPER_ACL)) &&
      (uc_update_queries[lex->sql_command] > 0))
  {
    send_error(&thd->net,ER_CANT_UPDATE_WITH_READLOCK);
    DBUG_VOID_RETURN;
  }

  statistic_increment(com_stat[lex->sql_command],&LOCK_status);
  switch (lex->sql_command) {
  case SQLCOM_SELECT:
  {
    select_result *result;
    if (select_lex->options & SELECT_DESCRIBE)
      lex->exchange=0;
    if (tables)
    {
      res=check_table_access(thd,
			     lex->exchange ? SELECT_ACL | FILE_ACL :
			     SELECT_ACL,
			     tables);
    }
    else
      res=check_access(thd, lex->exchange ? SELECT_ACL | FILE_ACL : SELECT_ACL,
		       any_db);
    if (res)
    {
      res=0;
      break;					// Error message is given
    }

    thd->offset_limit=select_lex->offset_limit;
    thd->select_limit=select_lex->select_limit+select_lex->offset_limit;
    if (thd->select_limit < select_lex->select_limit)
      thd->select_limit= HA_POS_ERROR;		// no limit
    if (thd->select_limit == HA_POS_ERROR)
      select_lex->options&= ~OPTION_FOUND_ROWS;

    if (lex->exchange)
    {
      if (lex->exchange->dumpfile)
      {
	if (!(result=new select_dump(lex->exchange)))
	{
	  res= -1;
	  break;
	}
      }
      else
      {
	if (!(result=new select_export(lex->exchange)))
	{
	  res= -1;
	  break;
	}
      }
    }
    else if (!(result=new select_send()))
    {
      res= -1;
#ifdef DELETE_ITEMS
      delete select_lex->having;
      delete select_lex->where;
#endif
      break;
    }
    else
    {
      /*
	Normal select:
	Change lock if we are using SELECT HIGH PRIORITY,
	FOR UPDATE or IN SHARE MODE

	TODO: Delete the following loop when locks is set by sql_yacc
      */
      TABLE_LIST *table;
      for (table = tables ; table ; table=table->next)
	table->lock_type= lex->lock_option;
    }

    if (!(res=open_and_lock_tables(thd,tables)))
    {
      query_cache_store_query(thd, tables);
      res=handle_select(thd, lex, result);
    }
    else
      delete result;
    break;
  }
  case SQLCOM_DO:
    res=mysql_do(thd, *lex->insert_list);
    break;

  case SQLCOM_EMPTY_QUERY:
    send_ok(&thd->net);
    break;

  case SQLCOM_PURGE:
  {
    if (check_global_access(thd, SUPER_ACL))
      goto error;
    res = purge_master_logs(thd, lex->to_log);
    break;
  }
  case SQLCOM_SHOW_NEW_MASTER:
  {
    if (check_global_access(thd, REPL_SLAVE_ACL))
      goto error;
    /* This query don't work now. See comment in repl_failsafe.cc */
#ifndef WORKING_NEW_MASTER
    net_printf(&thd->net, ER_NOT_SUPPORTED_YET, "SHOW NEW MASTER");
    res= 1;
#else
    res = show_new_master(thd);
#endif
    break;
  }
  case SQLCOM_SHOW_SLAVE_HOSTS:
  {
    if (check_global_access(thd, REPL_SLAVE_ACL))
      goto error;
    res = show_slave_hosts(thd);
    break;
  }
  case SQLCOM_SHOW_BINLOG_EVENTS:
  {
    if (check_global_access(thd, REPL_SLAVE_ACL))
      goto error;
    res = show_binlog_events(thd);
    break;
  }
  case SQLCOM_BACKUP_TABLE:
  {
    if (check_db_used(thd,tables) ||
	check_table_access(thd,SELECT_ACL, tables) ||
	check_global_access(thd, FILE_ACL))
      goto error; /* purecov: inspected */
    res = mysql_backup_table(thd, tables);

    break;
  }
  case SQLCOM_RESTORE_TABLE:
  {
    if (check_db_used(thd,tables) ||
	check_table_access(thd, INSERT_ACL, tables) ||
	check_global_access(thd, FILE_ACL))
      goto error; /* purecov: inspected */
    res = mysql_restore_table(thd, tables);
    break;
  }

#ifdef HAVE_REPLICATION
  case SQLCOM_CHANGE_MASTER:
  {
    if (check_global_access(thd, SUPER_ACL))
      goto error;
    pthread_mutex_lock(&LOCK_active_mi);
    res = change_master(thd,active_mi);
    pthread_mutex_unlock(&LOCK_active_mi);
    break;
  }
  case SQLCOM_SHOW_SLAVE_STAT:
  {
    /* Accept one of two privileges */
    if (check_global_access(thd, SUPER_ACL | REPL_CLIENT_ACL))
      goto error;
    pthread_mutex_lock(&LOCK_active_mi);
    res = show_master_info(thd,active_mi);
    pthread_mutex_unlock(&LOCK_active_mi);
    break;
  }
  case SQLCOM_SHOW_MASTER_STAT:
  {
    /* Accept one of two privileges */
    if (check_global_access(thd, SUPER_ACL | REPL_CLIENT_ACL))
      goto error;
    res = show_binlog_info(thd);
    break;
  }
    
  case SQLCOM_LOAD_MASTER_DATA: // sync with master
    if (check_global_access(thd, SUPER_ACL))
      goto error;
    if (end_active_trans(thd))
      res= -1;
    else
      res = load_master_data(thd);
    break;

#endif /* HAVE_REPLICATION */
    
#ifdef HAVE_INNOBASE_DB
  case SQLCOM_SHOW_INNODB_STATUS:
    {
      if (check_global_access(thd, SUPER_ACL))
	goto error;
      res = innodb_show_status(thd);
      break;
    }
#endif

#ifdef HAVE_REPLICATION
  case SQLCOM_LOAD_MASTER_TABLE:
  {
    if (!tables->db)
      tables->db=thd->db;
    if (check_access(thd,CREATE_ACL,tables->db,&tables->grant.privilege))
      goto error;				/* purecov: inspected */
    if (grant_option)
    {
      /* Check that the first table has CREATE privilege */
      TABLE_LIST *tmp_table_list=tables->next;
      tables->next=0;
      bool error=check_grant(thd,CREATE_ACL,tables);
      tables->next=tmp_table_list;
      if (error)
	goto error;
    }
    pthread_mutex_lock(&LOCK_active_mi);
    /*
      fetch_master_table will send the error to the client on failure.
      Give error if the table already exists.
    */
    if (!fetch_master_table(thd, tables->db, tables->real_name,
			    active_mi, 0, 0))
    {
      send_ok(&thd->net);
    }
    pthread_mutex_unlock(&LOCK_active_mi);
    break;
  }
#endif /* HAVE_REPLICATION */

  case SQLCOM_CREATE_TABLE:
  {
    ulong want_priv= ((lex->create_info.options & HA_LEX_CREATE_TMP_TABLE) ?
		      CREATE_TMP_ACL : CREATE_ACL);
    if (!tables->db)
      tables->db=thd->db;
    lex->create_info.alias= tables->alias;
    if (check_access(thd,want_priv,tables->db,&tables->grant.privilege) ||
	check_merge_table_access(thd, tables->db,
				 (TABLE_LIST *)
				 lex->create_info.merge_list.first))
      goto error;				/* purecov: inspected */
    if (grant_option && want_priv != CREATE_TMP_ACL)
    {
      /* Check that the first table has CREATE privilege */
      TABLE_LIST *tmp_table_list=tables->next;
      tables->next=0;
      bool error=check_grant(thd, want_priv, tables);
      tables->next=tmp_table_list;
      if (error)
	goto error;
    }
    if (strlen(tables->real_name) > NAME_LEN)
    {
      net_printf(&thd->net, ER_WRONG_TABLE_NAME, tables->alias);
      res=0;
      break;
    }
#ifndef HAVE_READLINK
    lex->create_info.data_file_name=lex->create_info.index_file_name=0;
#else
    /* Fix names if symlinked tables */
    if (append_file_to_dir(thd, &lex->create_info.data_file_name,
			   tables->real_name) ||
	append_file_to_dir(thd,&lex->create_info.index_file_name,
			   tables->real_name))
    {
      res=-1;
      break;
    }
#endif
    if (select_lex->item_list.elements)		// With select
    {
      select_result *result;

      if (!(lex->create_info.options & HA_LEX_CREATE_TMP_TABLE) &&
	  check_dup(tables->db, tables->real_name, tables->next))
      {
	net_printf(&thd->net,ER_INSERT_TABLE_USED,tables->real_name);
	DBUG_VOID_RETURN;
      }
      if (tables->next)
      {
	TABLE_LIST *table;
	if (check_table_access(thd, SELECT_ACL, tables->next))
	  goto error;				// Error message is given
	/* TODO: Delete the following loop when locks is set by sql_yacc */
	for (table = tables->next ; table ; table=table->next)
	  table->lock_type= lex->lock_option;
      }
      select_lex->options|= SELECT_NO_UNLOCK;
      thd->offset_limit=select_lex->offset_limit;
      thd->select_limit=select_lex->select_limit+select_lex->offset_limit;
      if (thd->select_limit < select_lex->select_limit)
	thd->select_limit= HA_POS_ERROR;		// No limit

      /* Skip first table, which is the table we are creating */
      lex->select_lex.table_list.first=
	(byte*) (((TABLE_LIST *) lex->select_lex.table_list.first)->next);
      if (!(res=open_and_lock_tables(thd,tables->next)))
      {
        if ((result=new select_create(tables->db ? tables->db : thd->db,
                                      tables->real_name,
				      &lex->create_info,
                                      lex->create_list,
                                      lex->key_list,
                                      select_lex->item_list,lex->duplicates)))
          res=handle_select(thd, lex, result);
	else
	  res= -1;
      }
    }
    else // regular create
    {
      res = mysql_create_table(thd,tables->db ? tables->db : thd->db,
			       tables->real_name,
			       &lex->create_info,
			       lex->create_list,
			       lex->key_list,0);
      if (!res)
	send_ok(&thd->net);
    }
    break;
  }
  case SQLCOM_CREATE_INDEX:
    if (check_one_table_access(thd, INDEX_ACL, tables, 0))
      goto error; /* purecov: inspected */
    if (end_active_trans(thd))
      res= -1;
    else
      res = mysql_create_index(thd, tables, lex->key_list);
    break;

#ifdef HAVE_REPLICATION
  case SQLCOM_SLAVE_START:
  {
    pthread_mutex_lock(&LOCK_active_mi);
    start_slave(thd,active_mi,1 /* net report*/);
    pthread_mutex_unlock(&LOCK_active_mi);
    break;
  }
  case SQLCOM_SLAVE_STOP:
  /*
    If the client thread has locked tables, a deadlock is possible.
    Assume that
    - the client thread does LOCK TABLE t READ.
    - then the master updates t.
    - then the SQL slave thread wants to update t,
      so it waits for the client thread because t is locked by it.
    - then the client thread does SLAVE STOP.
      SLAVE STOP waits for the SQL slave thread to terminate its
      update t, which waits for the client thread because t is locked by it.
    To prevent that, refuse SLAVE STOP if the
    client thread has locked tables
  */
  if (thd->locked_tables || thd->active_transaction())
  {
    send_error(&thd->net,ER_LOCK_OR_ACTIVE_TRANSACTION);
    break;
  }
  {
    pthread_mutex_lock(&LOCK_active_mi);
    stop_slave(thd,active_mi,1/* net report*/);
    pthread_mutex_unlock(&LOCK_active_mi);
    break;
  }
#endif /* HAVE_REPLICATION */

  case SQLCOM_ALTER_TABLE:
#if defined(DONT_ALLOW_SHOW_COMMANDS)
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND); /* purecov: inspected */
    break;
#else
    {
      ulong priv=0;
      if (lex->name && (!lex->name[0] || strlen(lex->name) > NAME_LEN))
      {
	net_printf(&thd->net,ER_WRONG_TABLE_NAME,lex->name);
	res=0;
	break;
      }
      if (!select_lex->db)
	select_lex->db=tables->db;
      if (check_access(thd,ALTER_ACL,tables->db,&tables->grant.privilege) ||
	  check_access(thd,INSERT_ACL | CREATE_ACL,select_lex->db,&priv) ||
	  check_merge_table_access(thd, tables->db, 
				   (TABLE_LIST *)
				   lex->create_info.merge_list.first))
	goto error;				/* purecov: inspected */
      if (grant_option)
      {
	if (check_grant(thd,ALTER_ACL,tables))
	  goto error;
	if (lex->name && !test_all_bits(priv,INSERT_ACL | CREATE_ACL))
	{					// Rename of table
	  TABLE_LIST tmp_table;
	  bzero((char*) &tmp_table,sizeof(tmp_table));
	  tmp_table.real_name=lex->name;
	  tmp_table.db=select_lex->db;
	  tmp_table.grant.privilege=priv;
	  if (check_grant(thd,INSERT_ACL | CREATE_ACL, &tmp_table))
	    goto error;
	}
      }
      /* Don't yet allow changing of symlinks with ALTER TABLE */
      lex->create_info.data_file_name=lex->create_info.index_file_name=0;
      /* ALTER TABLE ends previous transaction */
      if (end_active_trans(thd))
	res= -1;
      else
      {
	res= mysql_alter_table(thd, select_lex->db, lex->name,
			       &lex->create_info,
			       tables, lex->create_list,
			       lex->key_list, lex->drop_list, lex->alter_list,
                               (ORDER *) select_lex->order_list.first,
			       lex->drop_primary, lex->duplicates,
			       lex->alter_keys_onoff, lex->simple_alter);
      }
      break;
    }
#endif
  case SQLCOM_RENAME_TABLE:
  {
    TABLE_LIST *table;
    if (check_db_used(thd,tables))
      goto error;
    for (table=tables ; table ; table=table->next->next)
    {
      if (check_access(thd, ALTER_ACL | DROP_ACL, table->db,
		       &table->grant.privilege) ||
	  check_access(thd, INSERT_ACL | CREATE_ACL, table->next->db,
		       &table->next->grant.privilege))
	goto error;
      if (grant_option)
      {
	TABLE_LIST old_list,new_list;
	old_list=table[0];
	new_list=table->next[0];
	old_list.next=new_list.next=0;
	if (check_grant(thd,ALTER_ACL,&old_list) ||
	    (!test_all_bits(table->next->grant.privilege,
			    INSERT_ACL | CREATE_ACL) &&
	     check_grant(thd,INSERT_ACL | CREATE_ACL, &new_list)))
	  goto error;
      }
    }
    query_cache_invalidate3(thd, tables, 0);
    if (end_active_trans(thd))
      res= -1;
    else if (mysql_rename_tables(thd,tables))
      res= -1;
    break;
  }
  case SQLCOM_SHOW_BINLOGS:
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND); /* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      if (check_global_access(thd, SUPER_ACL))
	goto error;
      res = show_binlogs(thd);
      break;
    }
#endif    
  case SQLCOM_SHOW_CREATE:
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND); /* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      if (check_db_used(thd, tables) ||
	  check_access(thd, SELECT_ACL | EXTRA_ACL, tables->db,
		       &tables->grant.privilege))
	goto error;
      res = mysqld_show_create(thd, tables);
      break;
    }
#endif
  case SQLCOM_REPAIR:
  {
    if (check_db_used(thd,tables) ||
	check_table_access(thd,SELECT_ACL | INSERT_ACL, tables))
      goto error; /* purecov: inspected */
    res = mysql_repair_table(thd, tables, &lex->check_opt);
    break;
  }
  case SQLCOM_CHECK:
  {
    if (check_db_used(thd,tables) ||
	check_table_access(thd, SELECT_ACL | EXTRA_ACL , tables))
      goto error; /* purecov: inspected */
    res = mysql_check_table(thd, tables, &lex->check_opt);
    break;
  }
  case SQLCOM_ANALYZE:
  {
    if (check_db_used(thd,tables) ||
	check_table_access(thd,SELECT_ACL | INSERT_ACL, tables))
      goto error; /* purecov: inspected */
    res = mysql_analyze_table(thd, tables, &lex->check_opt);
    break;
  }

  case SQLCOM_OPTIMIZE:
  {
    HA_CREATE_INFO create_info;
    if (check_db_used(thd,tables) ||
	check_table_access(thd,SELECT_ACL | INSERT_ACL, tables))
      goto error; /* purecov: inspected */
    if (specialflag & (SPECIAL_SAFE_MODE | SPECIAL_NO_NEW_FUNC))
    {
      /* Use ALTER TABLE */
      lex->create_list.empty();
      lex->key_list.empty();
      lex->col_list.empty();
      lex->drop_list.empty();
      lex->alter_list.empty();
      bzero((char*) &create_info,sizeof(create_info));
      create_info.db_type=DB_TYPE_DEFAULT;
      create_info.row_type=ROW_TYPE_DEFAULT;
      res= mysql_alter_table(thd, NullS, NullS, &create_info,
			     tables, lex->create_list,
			     lex->key_list, lex->drop_list, lex->alter_list,
                             (ORDER *) 0,
			     0,DUP_ERROR);
    }
    else
      res = mysql_optimize_table(thd, tables, &lex->check_opt);
    break;
  }
  case SQLCOM_UPDATE:
    if (check_db_used(thd,tables))
      goto error;
    if (select_lex->item_list.elements != lex->value_list.elements)
    {
      send_error(&thd->net,ER_WRONG_VALUE_COUNT);
      DBUG_VOID_RETURN;
    }
    if (select_lex->table_list.elements == 1)
    {
      if (check_one_table_access(thd, UPDATE_ACL, tables, 0))
	goto error; /* purecov: inspected */


      res= mysql_update(thd,tables,
			select_lex->item_list,
			lex->value_list,
			select_lex->where,
			(ORDER *) select_lex->order_list.first,
			select_lex->select_limit,
			lex->duplicates);
    }
    else
    {
      const char *msg= 0;
      TABLE_LIST *table;
      lex->sql_command= SQLCOM_MULTI_UPDATE;

      /*
	Ensure that we have UPDATE or SELECT privilege for each table
	The exact privilege is checked in mysql_multi_update()
      */
      for (table= tables ; table ; table= table->next)
      {
	TABLE_LIST *save= table->next;
	table->next= 0;
	if (check_one_table_access(thd, UPDATE_ACL, table, 1) &&
	    check_one_table_access(thd, SELECT_ACL, table, 0))
	    goto error;
	table->next= save;
      }
      if (select_lex->order_list.elements)
	msg="ORDER BY";
      else if (select_lex->select_limit && select_lex->select_limit !=
	       HA_POS_ERROR)
	msg="LIMIT";
      if (msg)
      {
	net_printf(&thd->net, ER_WRONG_USAGE, "UPDATE", msg);
	res= 1;
	break;
      }
      res= mysql_multi_update(thd,tables,
			      &select_lex->item_list,
			      &lex->value_list,
			      select_lex->where,
			      select_lex->options,
			      lex->duplicates);
    }
    break;
  case SQLCOM_INSERT:
    if (check_one_table_access(thd, INSERT_ACL, tables, 0))
      goto error; /* purecov: inspected */
    res = mysql_insert(thd,tables,lex->field_list,lex->many_values,
		       lex->duplicates);
    break;
  case SQLCOM_REPLACE:
    if (check_one_table_access(thd, INSERT_ACL | DELETE_ACL, tables, 0))
      goto error; /* purecov: inspected */
    res = mysql_insert(thd,tables,lex->field_list,lex->many_values,
		       DUP_REPLACE);
    break;
  case SQLCOM_REPLACE_SELECT:
  case SQLCOM_INSERT_SELECT:
  {
    {
      /*
	Check that we have modify privileges for the first table and
	select privileges for the rest
      */
      ulong privilege= (lex->sql_command == SQLCOM_INSERT_SELECT ?
			INSERT_ACL : INSERT_ACL | DELETE_ACL);
      TABLE_LIST *save_next=tables->next;
      tables->next=0;
      if (check_one_table_access(thd, privilege, tables, 0))
	goto error;
      tables->next=save_next;
      if ((res=check_table_access(thd, SELECT_ACL, save_next)))
	goto error;
    }
    /* Fix lock for first table */
    if (tables->lock_type == TL_WRITE_DELAYED)
      tables->lock_type= TL_WRITE;

    /* Don't unlock tables until command is written to binary log */
    select_lex->options|= SELECT_NO_UNLOCK;

    select_result *result;
    thd->offset_limit=select_lex->offset_limit;
    thd->select_limit=select_lex->select_limit+select_lex->offset_limit;
    if (thd->select_limit < select_lex->select_limit)
      thd->select_limit= HA_POS_ERROR;		// No limit

    if (check_dup(tables->db, tables->real_name, tables->next))
    {
      /* Using same table for INSERT and SELECT */
      select_lex->options |= OPTION_BUFFER_RESULT;
    }
    {
      /* TODO: Delete the following loop when locks is set by sql_yacc */
      TABLE_LIST *table;
      for (table = tables->next ; table ; table=table->next)
	table->lock_type= lex->lock_option;
    }

    /* Skip first table, which is the table we are inserting in */
    lex->select_lex.table_list.first=
      (byte*) (((TABLE_LIST *) lex->select_lex.table_list.first)->next);
    if (!(res=open_and_lock_tables(thd, tables)))
    {
      if ((result=new select_insert(tables->table,&lex->field_list,
				    lex->duplicates)))
	res=handle_select(thd,lex,result);
    }
    else
      res= -1;
    break;
  }
  case SQLCOM_TRUNCATE:
    if (check_one_table_access(thd, DELETE_ACL, tables, 0))
      goto error; /* purecov: inspected */
    /*
      Don't allow this within a transaction because we want to use
      re-generate table
    */
    if (thd->locked_tables || thd->active_transaction())
    {
      send_error(&thd->net,ER_LOCK_OR_ACTIVE_TRANSACTION,NullS);
      goto error;
    }
    res=mysql_truncate(thd,tables);
    break;
  case SQLCOM_DELETE:
  {
    if (check_one_table_access(thd, DELETE_ACL, tables, 0))
      goto error;
    // Set privilege for the WHERE clause
    tables->grant.want_privilege=(SELECT_ACL & ~tables->grant.privilege);
    res = mysql_delete(thd,tables, select_lex->where,
                       (ORDER*) select_lex->order_list.first,
                       select_lex->select_limit, select_lex->options);
    break;
  }
  case SQLCOM_DELETE_MULTI:
  {
    TABLE_LIST *aux_tables=(TABLE_LIST *)thd->lex.auxilliary_table_list.first;
    TABLE_LIST *auxi;
    uint table_count=0;
    multi_delete *result;

    /* sql_yacc guarantees that tables and aux_tables are not zero */
    if (check_db_used(thd, tables) || check_db_used(thd,aux_tables) ||
	check_table_access(thd,SELECT_ACL, tables) || 
	check_table_access(thd,DELETE_ACL, aux_tables))
      goto error;
    if ((thd->options & OPTION_SAFE_UPDATES) && !select_lex->where)
    {		
      send_error(&thd->net,ER_UPDATE_WITHOUT_KEY_IN_SAFE_MODE);
      goto error;
    }
    for (auxi=(TABLE_LIST*) aux_tables ; auxi ; auxi=auxi->next)
    {
      table_count++;
      /* All tables in aux_tables must be found in FROM PART */
      TABLE_LIST *walk;
      for (walk=(TABLE_LIST*) tables ; walk ; walk=walk->next)
      {
	if (!strcmp(auxi->real_name,walk->real_name) &&
	    !strcmp(walk->db,auxi->db))
	  break;
      }
      if (!walk)
      {
	net_printf(&thd->net,ER_NONUNIQ_TABLE,auxi->real_name);
	goto error;
      }
      walk->lock_type= auxi->lock_type;
      // Store address to table as we need it later
      auxi->table= my_reinterpret_cast(TABLE *) (walk);
    }
    if (add_item_to_list(new Item_null()))
    {
      res= -1;
      break;
    }
    tables->grant.want_privilege=(SELECT_ACL & ~tables->grant.privilege);
    thd->proc_info="init";
    if ((res=open_and_lock_tables(thd,tables)))
      break;
    /* Fix tables-to-be-deleted-from list to point at opened tables */
    for (auxi=(TABLE_LIST*) aux_tables ; auxi ; auxi=auxi->next)
      auxi->table= (my_reinterpret_cast(TABLE_LIST*) (auxi->table))->table;

    if (!thd->fatal_error && (result= new multi_delete(thd,aux_tables,
						       table_count)))
    {
      res=mysql_select(thd,tables,select_lex->item_list,
		       select_lex->where,
		       (ORDER *)NULL,(ORDER *)NULL,(Item *)NULL,
		       (ORDER *)NULL,
		       select_lex->options | thd->options |
		       SELECT_NO_JOIN_CACHE | SELECT_NO_UNLOCK,
		       result);
      delete result;
    }
    else
      res= -1;					// Error is not sent
    close_thread_tables(thd);
    break;
  }
  case SQLCOM_DROP_TABLE:
  {
    if (check_table_access(thd,DROP_ACL,tables))
      goto error;				/* purecov: inspected */
    /*
      If this is a slave thread, we may sometimes execute some 
      DROP / * 40005 TEMPORARY * / TABLE
      that come from parts of binlogs (likely if we use RESET SLAVE or CHANGE
      MASTER TO), while the temporary table has already been dropped.
      To not generate such irrelevant "table does not exist errors",
      we silently add IF EXISTS if TEMPORARY was used.
    */
    if (thd->slave_thread && lex->drop_temporary)
      lex->drop_if_exists= 1;
    if (end_active_trans(thd))
      res= -1;
    else
      res = mysql_rm_table(thd,tables,lex->drop_if_exists);
  }
  break;
  case SQLCOM_DROP_INDEX:
    if (check_one_table_access(thd, INDEX_ACL, tables, 0))
      goto error; /* purecov: inspected */
    if (end_active_trans(thd))
      res= -1;
    else
      res = mysql_drop_index(thd, tables, lex->drop_list);
    break;
  case SQLCOM_SHOW_DATABASES:
#if defined(DONT_ALLOW_SHOW_COMMANDS)
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND);   /* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    if ((specialflag & SPECIAL_SKIP_SHOW_DB) &&
	check_global_access(thd, SHOW_DB_ACL))
      goto error;
    res= mysqld_show_dbs(thd, (lex->wild ? lex->wild->ptr() : NullS));
    break;
#endif
  case SQLCOM_SHOW_PROCESSLIST:
    if (!thd->priv_user[0] && check_global_access(thd,PROCESS_ACL))
      break;
    mysqld_list_processes(thd,thd->master_access & PROCESS_ACL ? NullS :
			  thd->priv_user,lex->verbose);
    break;
  case SQLCOM_SHOW_STATUS:
    res= mysqld_show(thd,(lex->wild ? lex->wild->ptr() : NullS),status_vars,
		     OPT_GLOBAL, &LOCK_status);
    break;
  case SQLCOM_SHOW_VARIABLES:
    res= mysqld_show(thd, (lex->wild ? lex->wild->ptr() : NullS),
		     init_vars, lex->option_type,
		     &LOCK_global_system_variables);
    break;
  case SQLCOM_SHOW_LOGS:
  {
    res= mysqld_show_logs(thd);
    break;
  }
  case SQLCOM_SHOW_TABLES:
    /* FALL THROUGH */
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      char *db=select_lex->db ? select_lex->db : thd->db;
      if (!db)
      {
	send_error(&thd->net,ER_NO_DB_ERROR);	/* purecov: inspected */
	goto error;				/* purecov: inspected */
      }
      remove_escape(db);				// Fix escaped '_'
      if (check_db_name(db))
      {
        net_printf(&thd->net,ER_WRONG_DB_NAME, db);
        goto error;
      }
      if (check_access(thd,SELECT_ACL,db,&thd->col_access))
	goto error;				/* purecov: inspected */
      if (!thd->col_access && check_grant_db(thd,db))
      {
	net_printf(&thd->net,ER_DBACCESS_DENIED_ERROR,
		   thd->priv_user,
		   thd->priv_host,
		   db);
	goto error;
      }
      /* grant is checked in mysqld_show_tables */
      if (select_lex->options & SELECT_DESCRIBE)
        res= mysqld_extend_show_tables(thd,db,
				       (lex->wild ? lex->wild->ptr() : NullS));
      else
	res= mysqld_show_tables(thd,db,
				(lex->wild ? lex->wild->ptr() : NullS));
      break;
    }
#endif
  case SQLCOM_SHOW_OPEN_TABLES:
    res= mysqld_show_open_tables(thd,(lex->wild ? lex->wild->ptr() : NullS));
    break;
  case SQLCOM_SHOW_FIELDS:
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      char *db=tables->db;
      remove_escape(db);			// Fix escaped '_'
      remove_escape(tables->real_name);
      if (check_access(thd,SELECT_ACL | EXTRA_ACL,db,
		       &tables->grant.privilege))
	goto error;				/* purecov: inspected */
      if (grant_option && check_grant(thd,SELECT_ACL,tables,2))
	goto error;
      res= mysqld_show_fields(thd,tables,
			      (lex->wild ? lex->wild->ptr() : NullS),
			      lex->verbose);
      break;
    }
#endif
  case SQLCOM_SHOW_KEYS:
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(&thd->net,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      char *db=tables->db;
      remove_escape(db);			// Fix escaped '_'
      remove_escape(tables->real_name);
      if (check_access(thd,SELECT_ACL,db,&tables->grant.privilege))
	goto error; /* purecov: inspected */
      if (grant_option && check_grant(thd,SELECT_ACL,tables,2))
	goto error;
      res= mysqld_show_keys(thd,tables);
      break;
    }
#endif
  case SQLCOM_CHANGE_DB:
    mysql_change_db(thd,select_lex->db);
    break;
  case SQLCOM_LOAD:
  {
    uint privilege= (lex->duplicates == DUP_REPLACE ?
		     INSERT_ACL | UPDATE_ACL | DELETE_ACL : INSERT_ACL);

    if (!lex->local_file)
    {
      if (check_access(thd,privilege | FILE_ACL,tables->db))
	goto error;
    }
    else
    {
      if (!(thd->client_capabilities & CLIENT_LOCAL_FILES) ||
	  ! opt_local_infile)
      {
	send_error(&thd->net,ER_NOT_ALLOWED_COMMAND);
	goto error;
      }
      if (check_one_table_access(thd, privilege, tables, 0))
	goto error;
    }
    res=mysql_load(thd, lex->exchange, tables, lex->field_list,
		   lex->duplicates, (bool) lex->local_file, lex->lock_option);
    break;
  }
  case SQLCOM_SET_OPTION:
    if (!(res=sql_set_variables(thd, &lex->var_list)))
      send_ok(&thd->net);
    break;
  case SQLCOM_UNLOCK_TABLES:
    unlock_locked_tables(thd);
    if (thd->options & OPTION_TABLE_LOCK)
    {
      end_active_trans(thd);
      thd->options&= ~(ulong) (OPTION_TABLE_LOCK);
    }
    if (thd->global_read_lock)
      unlock_global_read_lock(thd);
    send_ok(&thd->net);
    break;
  case SQLCOM_LOCK_TABLES:
    unlock_locked_tables(thd);
    if (check_db_used(thd,tables) || end_active_trans(thd))
      goto error;
    if (check_table_access(thd, LOCK_TABLES_ACL | SELECT_ACL, tables))
      goto error;
    thd->in_lock_tables=1;
    thd->options|= OPTION_TABLE_LOCK;
    if (!(res= open_and_lock_tables(thd, tables)))
    {
#ifdef HAVE_QUERY_CACHE
      if (thd->variables.query_cache_wlock_invalidate)
	query_cache.invalidate_locked_for_write(tables);
#endif /*HAVE_QUERY_CACHE*/
      thd->locked_tables=thd->lock;
      thd->lock=0;
      send_ok(&thd->net);
    }
    else
      thd->options&= ~(ulong) (OPTION_TABLE_LOCK);
    thd->in_lock_tables=0;
    break;
  case SQLCOM_CREATE_DB:
  {
    char *alias;
    if (!(alias=thd->strdup(lex->name)) || check_db_name(lex->name))
    {
      net_printf(&thd->net,ER_WRONG_DB_NAME, lex->name);
      break;
    }
    /*
      If in a slave thread :
      CREATE DATABASE DB was certainly not preceded by USE DB.
      For that reason, db_ok() in sql/slave.cc did not check the 
      do_db/ignore_db. And as this query involves no tables, tables_ok()
      above was not called. So we have to check rules again here.
    */
    if (thd->slave_thread && 
	(!db_ok(lex->name, replicate_do_db, replicate_ignore_db) ||
	 !db_ok_with_wild_table(lex->name)))
    {
      my_error(ER_SLAVE_IGNORED_TABLE, MYF(0));
      break;
    }

    if (check_access(thd,CREATE_ACL,lex->name,0,1))
      break;
    res=mysql_create_db(thd,(lower_case_table_names == 2 ? alias : lex->name),
			lex->create_info.options,0);
    break;
  }
  case SQLCOM_DROP_DB:
  {
    char *alias;
    if (!(alias=thd->strdup(lex->name)) || check_db_name(lex->name))
    {
      net_printf(&thd->net,ER_WRONG_DB_NAME, lex->name);
      break;
    }
    /*
      If in a slave thread :
      DROP DATABASE DB may not be preceded by USE DB.
      For that reason, maybe db_ok() in sql/slave.cc did not check the 
      do_db/ignore_db. And as this query involves no tables, tables_ok()
      above was not called. So we have to check rules again here.
    */
    if (thd->slave_thread && 
	(!db_ok(lex->name, replicate_do_db, replicate_ignore_db) ||
	 !db_ok_with_wild_table(lex->name)))
    {
      my_error(ER_SLAVE_IGNORED_TABLE, MYF(0));
      break;
    }
    if (check_access(thd,DROP_ACL,lex->name,0,1))
      break;
    if (thd->locked_tables || thd->active_transaction())
    {
      send_error(&thd->net,ER_LOCK_OR_ACTIVE_TRANSACTION);
      goto error;
    }
    res=mysql_rm_db(thd, (lower_case_table_names == 2 ? alias : lex->name),
                    lex->drop_if_exists, 0);
    break;
  }
  case SQLCOM_CREATE_FUNCTION:
    if (check_access(thd,INSERT_ACL,"mysql",0,1))
      break;
#ifdef HAVE_DLOPEN
    if (!(res = mysql_create_function(thd,&lex->udf)))
      send_ok(&thd->net);
#else
    res= -1;
#endif
    break;
  case SQLCOM_DROP_FUNCTION:
    if (check_access(thd,DELETE_ACL,"mysql",0,1))
      break;
#ifdef HAVE_DLOPEN
    if (!(res = mysql_drop_function(thd,lex->udf.name)))
      send_ok(&thd->net);
#else
    res= -1;
#endif
    break;
  case SQLCOM_REVOKE:
  case SQLCOM_GRANT:
  {
    if (check_access(thd, lex->grant | lex->grant_tot_col | GRANT_ACL,
		     tables && tables->db ? tables->db : select_lex->db,
		     tables ? &tables->grant.privilege : 0,
		     tables ? 0 : 1))
      goto error;

    /*
      Check that the user isn't trying to change a password for another
      user if he doesn't have UPDATE privilege to the MySQL database
    */

    if (thd->user)				// If not replication
    {
      LEX_USER *user;
      List_iterator <LEX_USER> user_list(lex->users_list);
      while ((user=user_list++))
      {
	if (user->password.str &&
	    (strcmp(thd->user,user->user.str) ||
	     user->host.str &&
	     my_strcasecmp(user->host.str, thd->host_or_ip)))
	{
	  if (check_access(thd, UPDATE_ACL, "mysql",0,1))
	    goto error;
	  break;			// We are allowed to do changes
	}
      }
    }
    if (tables)
    {
      if (grant_option && check_grant(thd,
				      (lex->grant | lex->grant_tot_col |
				       GRANT_ACL),
				      tables))
	goto error;
      if (!(res = mysql_table_grant(thd,tables,lex->users_list, lex->columns,
				    lex->grant,
				    lex->sql_command == SQLCOM_REVOKE)))
      {
	mysql_update_log.write(thd, thd->query, thd->query_length);
	if (mysql_bin_log.is_open())
	{
          thd->clear_error();
	  Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
	  mysql_bin_log.write(&qinfo);
	}
      }
    }
    else
    {
      if (lex->columns.elements)
      {
	send_error(&thd->net,ER_ILLEGAL_GRANT_FOR_TABLE);
	res=1;
      }
      else
	res = mysql_grant(thd, select_lex->db, lex->users_list, lex->grant,
			  lex->sql_command == SQLCOM_REVOKE);
      if (!res)
      {
	mysql_update_log.write(thd, thd->query, thd->query_length);
	if (mysql_bin_log.is_open())
	{
          thd->clear_error();
	  Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
	  mysql_bin_log.write(&qinfo);
	}
	if (mqh_used && lex->sql_command == SQLCOM_GRANT)
	{
	  List_iterator <LEX_USER> str_list(lex->users_list);
	  LEX_USER *user;
	  while ((user=str_list++))
	    reset_mqh(thd,user);
	}
      }
    }
    break;
  }
  case SQLCOM_FLUSH:
  case SQLCOM_RESET:
    if (check_global_access(thd,RELOAD_ACL) || check_db_used(thd, tables))
      goto error;
    /* error sending is deferred to reload_acl_and_cache */
    reload_acl_and_cache(thd, lex->type, tables) ;
    break;
  case SQLCOM_KILL:
    kill_one_thread(thd,lex->thread_id);
    break;
  case SQLCOM_SHOW_GRANTS:
    res=0;
    if ((thd->priv_user &&
	 !strcmp(thd->priv_user,lex->grant_user->user.str)) ||
	!check_access(thd, SELECT_ACL, "mysql",0,1))
    {
      res = mysql_show_grants(thd,lex->grant_user);
    }
    break;
  case SQLCOM_HA_OPEN:
    if (check_db_used(thd,tables) ||
	check_table_access(thd,SELECT_ACL, tables))
      goto error;
    res = mysql_ha_open(thd, tables);
    break;
  case SQLCOM_HA_CLOSE:
    if (check_db_used(thd,tables))
      goto error;
    res = mysql_ha_close(thd, tables);
    break;
  case SQLCOM_HA_READ:
    /*
      There is no need to check for table permissions here, because
      if a user has no permissions to read a table, he won't be
      able to open it (with SQLCOM_HA_OPEN) in the first place.
    */
    if (check_db_used(thd,tables))
      goto error;
    res = mysql_ha_read(thd, tables, lex->ha_read_mode, lex->backup_dir,
			lex->insert_list, lex->ha_rkey_mode, select_lex->where,
			select_lex->select_limit, select_lex->offset_limit);
    break;

  case SQLCOM_BEGIN:
    if (thd->locked_tables)
    {
      thd->lock=thd->locked_tables;
      thd->locked_tables=0;			// Will be automaticly closed
      close_thread_tables(thd);			// Free tables
    }
    if (end_active_trans(thd))
    {
      res= -1;
    }
    else
    {
      thd->options= ((thd->options & (ulong) ~(OPTION_STATUS_NO_TRANS_UPDATE)) |
		     OPTION_BEGIN);
      thd->server_status|= SERVER_STATUS_IN_TRANS;
      send_ok(&thd->net);
    }
    break;
  case SQLCOM_COMMIT:
    /*
      We don't use end_active_trans() here to ensure that this works
      even if there is a problem with the OPTION_AUTO_COMMIT flag
      (Which of course should never happen...)
    */
  {
    thd->options&= ~(ulong) (OPTION_BEGIN | OPTION_STATUS_NO_TRANS_UPDATE);
    thd->server_status&= ~SERVER_STATUS_IN_TRANS;
    if (!ha_commit(thd))
    {
      send_ok(&thd->net);
    }
    else
      res= -1;
    break;
  }
  case SQLCOM_ROLLBACK:
    thd->server_status&= ~SERVER_STATUS_IN_TRANS;
    if (!ha_rollback(thd))
    {
      /*
        If a non-transactional table was updated, warn; don't warn if this is a
        slave thread (because when a slave thread executes a ROLLBACK, it has
        been read from the binary log, so it's 100% sure and normal to produce
        error ER_WARNING_NOT_COMPLETE_ROLLBACK. If we sent the warning to the
        slave SQL thread, it would not stop the thread but just be printed in
        the error log; but we don't want users to wonder why they have this
        message in the error log, so we don't send it.
      */
      if ((thd->options & OPTION_STATUS_NO_TRANS_UPDATE) && !thd->slave_thread)
	send_warning(&thd->net,ER_WARNING_NOT_COMPLETE_ROLLBACK,0);
      else
	send_ok(&thd->net);
    }
    else
      res= -1;
    thd->options&= ~(ulong) (OPTION_BEGIN | OPTION_STATUS_NO_TRANS_UPDATE);
    break;
  case SQLCOM_ROLLBACK_TO_SAVEPOINT:
    if (!ha_rollback_to_savepoint(thd, lex->savepoint_name))
    {
      if ((thd->options & OPTION_STATUS_NO_TRANS_UPDATE) && !thd->slave_thread)
	send_warning(&thd->net,ER_WARNING_NOT_COMPLETE_ROLLBACK,0);
      else
	send_ok(&thd->net);
    }
    else
      res= -1;
    break;
  case SQLCOM_SAVEPOINT:
    if (!ha_savepoint(thd, lex->savepoint_name))
      send_ok(&thd->net);
    else
      res= -1;
    break;
  default:					/* Impossible */
    send_ok(&thd->net);
    break;
  }
  thd->proc_info="query end";			// QQ
  if (res < 0)
    send_error(&thd->net,thd->killed ? ER_SERVER_SHUTDOWN : 0);

error:
  DBUG_VOID_RETURN;
}


/****************************************************************************
  Get the user (global) and database privileges for all used tables

  NOTES
    The idea of EXTRA_ACL is that one will be granted access to the table if
    one has the asked privilege on any column combination of the table; For
    example to be able to check a table one needs to have SELECT privilege on
    any column of the table.

  RETURN
    0  ok
    1  If we can't get the privileges and we don't use table/column grants.

    save_priv	In this we store global and db level grants for the table
		Note that we don't store db level grants if the global grants
                is enough to satisfy the request and the global grants contains
                a SELECT grant.
****************************************************************************/

bool
check_access(THD *thd, ulong want_access, const char *db, ulong *save_priv,
	     bool dont_check_global_grants, bool no_errors)
{
  DBUG_ENTER("check_access");
  DBUG_PRINT("enter",("want_access: %lu  master_access: %lu", want_access,
		      thd->master_access));
  ulong db_access,dummy;
  if (save_priv)
    *save_priv=0;
  else
    save_priv= &dummy;

  if ((!db || !db[0]) && !thd->db && !dont_check_global_grants)
  {
    if (!no_errors)
      send_error(&thd->net,ER_NO_DB_ERROR);	/* purecov: tested */
    DBUG_RETURN(TRUE);				/* purecov: tested */
  }

  if ((thd->master_access & want_access) == want_access)
  {
    /*
      If we don't have a global SELECT privilege, we have to get the database
      specific access rights to be able to handle queries of type
      UPDATE t1 SET a=1 WHERE b > 0
    */
    db_access= thd->db_access;
    if (!(thd->master_access & SELECT_ACL) &&
	(db && (!thd->db || strcmp(db,thd->db))))
      db_access=acl_get(thd->host, thd->ip, (char*) &thd->remote.sin_addr,
			thd->priv_user, db, 0); /* purecov: inspected */
    *save_priv=thd->master_access | db_access;
    DBUG_RETURN(FALSE);
  }
  if (((want_access & ~thd->master_access) & ~(DB_ACLS | EXTRA_ACL)) ||
      ! db && dont_check_global_grants)
  {						// We can never grant this
    if (!no_errors)
      net_printf(&thd->net,ER_ACCESS_DENIED_ERROR,
		 thd->priv_user,
		 thd->priv_host,
		 thd->password ? ER(ER_YES) : ER(ER_NO));/* purecov: tested */
    DBUG_RETURN(TRUE);				/* purecov: tested */
  }

  if (db == any_db)
    DBUG_RETURN(FALSE);				// Allow select on anything

  if (db && (!thd->db || strcmp(db,thd->db)))
    db_access=acl_get(thd->host, thd->ip, (char*) &thd->remote.sin_addr,
		      thd->priv_user, db, 0); /* purecov: inspected */
  else
    db_access=thd->db_access;
  // Remove SHOW attribute and access rights we already have
  want_access &= ~(thd->master_access | EXTRA_ACL);
  db_access= ((*save_priv=(db_access | thd->master_access)) & want_access);

  /* grant_option is set if there exists a single table or column grant */
  if (db_access == want_access ||
      ((grant_option && !dont_check_global_grants) &&
       !(want_access & ~(db_access | TABLE_ACLS))))
    DBUG_RETURN(FALSE);				/* Ok */
  if (!no_errors)
    net_printf(&thd->net,ER_DBACCESS_DENIED_ERROR,
	       thd->priv_user,
	       thd->priv_host,
	       db ? db : thd->db ? thd->db : "unknown"); /* purecov: tested */
  DBUG_RETURN(TRUE);				/* purecov: tested */
}


/*
  check for global access and give descriptive error message if it fails

  SYNOPSIS
    check_global_access()
    thd			Thread handler
    want_access		Use should have any of these global rights

  WARNING
    One gets access rigth if one has ANY of the rights in want_access
    This is useful as one in most cases only need one global right,
    but in some case we want to check if the user has SUPER or
    REPL_CLIENT_ACL rights.

  RETURN
    0	ok
    1	Access denied.  In this case an error is sent to the client
*/

bool check_global_access(THD *thd, ulong want_access)
{
  char command[128];
  if ((thd->master_access & want_access))
    return 0;
  get_privilege_desc(command, sizeof(command), want_access);
  net_printf(&thd->net,ER_SPECIFIC_ACCESS_DENIED_ERROR,
	     command);
  return 1;
}


/*
  Check the privilege for all used tables.  Table privileges are cached
  in the table list for GRANT checking
*/

bool
check_table_access(THD *thd, ulong want_access,TABLE_LIST *tables,
		   bool no_errors)
{
  uint found=0;
  ulong found_access=0;
  TABLE_LIST *org_tables=tables;
  for (; tables ; tables=tables->next)
  {
    if ((thd->master_access & want_access) == (want_access & ~EXTRA_ACL) &&
	thd->db)
      tables->grant.privilege= want_access;
    else if (tables->db && tables->db == thd->db)
    {
      if (found && !grant_option)		// db already checked
	tables->grant.privilege=found_access;
      else
      {
	if (check_access(thd,want_access,tables->db,&tables->grant.privilege,
			 0, no_errors))
	  return TRUE;				// Access denied
	found_access=tables->grant.privilege;
	found=1;
      }
    }
    else if (check_access(thd,want_access,tables->db,&tables->grant.privilege,
			  0, no_errors))
      return TRUE;
  }
  if (grant_option)
    return check_grant(thd,want_access & ~EXTRA_ACL,org_tables,
		       test(want_access & EXTRA_ACL), no_errors);
  return FALSE;
}


static bool
check_one_table_access(THD *thd, ulong want_access, TABLE_LIST *table,
		       bool no_errors)
{
  if (check_access(thd, want_access, table->db, &table->grant.privilege, 0,
		   no_errors))
    return 1;
  return (grant_option && check_grant(thd, want_access, table, 0,
				      no_errors));
}


static bool check_db_used(THD *thd,TABLE_LIST *tables)
{
  for (; tables ; tables=tables->next)
  {
    if (!tables->db)
    {
      if (!(tables->db=thd->db))
      {
	send_error(&thd->net,ER_NO_DB_ERROR);	/* purecov: tested */
	return TRUE;				/* purecov: tested */
      }
    }
  }
  return FALSE;
}


static bool check_merge_table_access(THD *thd, char *db,
				     TABLE_LIST *table_list)
{
  int error=0;
  if (table_list)
  {
    /* Check that all tables use the current database */
    TABLE_LIST *tmp;
    for (tmp=table_list; tmp ; tmp=tmp->next)
    {
      if (!tmp->db || !tmp->db[0])
	tmp->db=db;
      else if (strcmp(tmp->db,db))
      {
	send_error(&thd->net,ER_UNION_TABLES_IN_DIFFERENT_DIR);
	return 1;
      }
    }
    error=check_table_access(thd, SELECT_ACL | UPDATE_ACL | DELETE_ACL,
			     table_list);
  }
  return error;
}


/****************************************************************************
	Check stack size; Send error if there isn't enough stack to continue
****************************************************************************/

#if STACK_DIRECTION < 0
#define used_stack(A,B) (long) (A - B)
#else
#define used_stack(A,B) (long) (B - A)
#endif

#ifndef EMBEDDED_LIBRARY
bool check_stack_overrun(THD *thd,char *buf __attribute__((unused)))
{
  long stack_used;
  if ((stack_used=used_stack(thd->thread_stack,(char*) &stack_used)) >=
      (long) thread_stack_min)
  {
    sprintf(errbuff[0],ER(ER_STACK_OVERRUN),stack_used,thread_stack);
    my_message(ER_STACK_OVERRUN,errbuff[0],MYF(0));
    thd->fatal_error=1;
    return 1;
  }
  return 0;
}
#endif /* EMBEDDED_LIBRARY */

#define MY_YACC_INIT 1000			// Start with big alloc
#define MY_YACC_MAX  32000			// Because of 'short'

bool my_yyoverflow(short **yyss, YYSTYPE **yyvs, ulong *yystacksize)
{
  LEX	*lex=current_lex;
  ulong old_info=0;
  if ((uint) *yystacksize >= MY_YACC_MAX)
    return 1;
  if (!lex->yacc_yyvs)
    old_info= *yystacksize;
  *yystacksize= set_zone((*yystacksize)*2,MY_YACC_INIT,MY_YACC_MAX);
  if (!(lex->yacc_yyvs= (char*)
	my_realloc((gptr) lex->yacc_yyvs,
		   *yystacksize*sizeof(**yyvs),
		   MYF(MY_ALLOW_ZERO_PTR | MY_FREE_ON_ERROR))) ||
      !(lex->yacc_yyss= (char*)
	my_realloc((gptr) lex->yacc_yyss,
		   *yystacksize*sizeof(**yyss),
		   MYF(MY_ALLOW_ZERO_PTR | MY_FREE_ON_ERROR))))
    return 1;
  if (old_info)
  {						// Copy old info from stack
    memcpy(lex->yacc_yyss, (gptr) *yyss, old_info*sizeof(**yyss));
    memcpy(lex->yacc_yyvs, (gptr) *yyvs, old_info*sizeof(**yyvs));
  }
  *yyss=(short*) lex->yacc_yyss;
  *yyvs=(YYSTYPE*) lex->yacc_yyvs;
  return 0;
}


/****************************************************************************
	Initialize global thd variables needed for query
****************************************************************************/

static void
mysql_init_query(THD *thd)
{
  DBUG_ENTER("mysql_init_query");
  thd->lex.select_lex.item_list.empty();
  thd->lex.value_list.empty();
  thd->lex.select_lex.table_list.elements=0;
  thd->free_list=0;  thd->lex.union_option=0;
  thd->lex.select = &thd->lex.select_lex;
  thd->lex.select_lex.table_list.first=0;
  thd->lex.select_lex.table_list.next= (byte**) &thd->lex.select_lex.table_list.first;
  thd->lex.select_lex.next=0;
  /*
    select_lex.options is also inited in dispatch_command(), but for
    replication (which bypasses dispatch_command() and calls mysql_parse()
    directly) we must do it here.
  */
  thd->lex.select_lex.options=0;
  thd->lex.olap=0;
  thd->lex.select->olap= UNSPECIFIED_OLAP_TYPE;
  thd->fatal_error=0;				// Safety
  thd->last_insert_id_used=thd->query_start_used=thd->insert_id_used=0;
  thd->rand_used=0;
  thd->sent_row_count=thd->examined_row_count=0;
  thd->safe_to_cache_query=1;
  DBUG_VOID_RETURN;
}

void
mysql_init_select(LEX *lex)
{
  SELECT_LEX *select_lex = lex->select;
  select_lex->where=select_lex->having=0;
  select_lex->select_limit= lex->thd->variables.select_limit;
  select_lex->offset_limit=0;
  select_lex->options=0;
  select_lex->linkage=UNSPECIFIED_TYPE;
  select_lex->olap=   UNSPECIFIED_OLAP_TYPE;
  lex->exchange = 0;
  lex->proc_list.first=0;
  select_lex->order_list.empty();
  select_lex->group_list.empty();
  select_lex->next = (SELECT_LEX *)NULL; 
}


bool
mysql_new_select(LEX *lex)
{
  SELECT_LEX *select_lex = (SELECT_LEX *) lex->thd->calloc(sizeof(SELECT_LEX));
  if (!select_lex)
    return 1;
  lex->select->next=select_lex; 
  lex->select=select_lex;
  select_lex->table_list.next= (byte**) &select_lex->table_list.first;
  select_lex->item_list.empty();
  select_lex->when_list.empty(); 
  select_lex->expr_list.empty();
  select_lex->interval_list.empty(); 
  select_lex->use_index.empty();
  select_lex->ftfunc_list.empty();
  return 0;
}


void mysql_init_multi_delete(LEX *lex)
{
  lex->sql_command =  SQLCOM_DELETE_MULTI;
  mysql_init_select(lex);
  lex->select->select_limit=lex->thd->select_limit=HA_POS_ERROR;
  lex->select->table_list.save_and_clear(&lex->auxilliary_table_list);
}


/*
  When you modify mysql_parse(), you may need to mofify
  mysql_test_parse_for_slave() in this same file.
*/
void mysql_parse(THD *thd, char *inBuf, uint length)
{
  DBUG_ENTER("mysql_parse");

  thd->query_length = length;
  mysql_init_query(thd);
  if (query_cache_send_result_to_client(thd, inBuf, length) <= 0)
  {
    LEX *lex=lex_start(thd, (uchar*) inBuf, length);
    if (!yyparse() && ! thd->fatal_error)
    {
      if (mqh_used && thd->user_connect &&
	  check_mqh(thd, thd->lex.sql_command))
      {
	thd->net.error = 0;
      }
      else
      {
	mysql_execute_command();
	query_cache_end_of_result(&thd->net);
      }
    }
    else
    {
      DBUG_PRINT("info",("Command aborted. Fatal_error: %d",
			 thd->fatal_error));
      query_cache_abort(&thd->net);
    }
    thd->proc_info="freeing items";
    free_items(thd);  /* Free strings used by items */
    lex_end(lex);
  }
  DBUG_VOID_RETURN;
}

/*
  Usable by the replication SQL thread only: just parse a query to know if it
  can be ignored because of replicate-*-table rules.

  RETURN VALUES
    0	cannot be ignored
    1	can be ignored
*/

bool mysql_test_parse_for_slave(THD *thd, char *inBuf, uint length)
{
  LEX *lex;
  bool error= 0;

  mysql_init_query(thd);
  lex= lex_start(thd, (uchar*) inBuf, length);
  if (!yyparse() && ! thd->fatal_error &&
      all_tables_not_ok(thd,(TABLE_LIST*) lex->select_lex.table_list.first))
    error= 1;                /* Ignore question */
  free_items(thd);  /* Free strings used by items */
  lex_end(lex);

  return error;
}


/*****************************************************************************
** Store field definition for create
** Return 0 if ok
******************************************************************************/

bool add_field_to_list(char *field_name, enum_field_types type,
		       char *length, char *decimals,
		       uint type_modifier, Item *default_value,char *change,
		       TYPELIB *interval)
{
  register create_field *new_field;
  THD	*thd=current_thd;
  LEX  *lex= &thd->lex;
  uint allowed_type_modifier=0;
  DBUG_ENTER("add_field_to_list");

  if (strlen(field_name) > NAME_LEN)
  {
    net_printf(&thd->net, ER_TOO_LONG_IDENT, field_name); /* purecov: inspected */
    DBUG_RETURN(1);				/* purecov: inspected */
  }
  if (type_modifier & PRI_KEY_FLAG)
  {
    lex->col_list.push_back(new key_part_spec(field_name,0));
    lex->key_list.push_back(new Key(Key::PRIMARY,NullS,
				    lex->col_list));
    lex->col_list.empty();
  }
  if (type_modifier & (UNIQUE_FLAG | UNIQUE_KEY_FLAG))
  {
    lex->col_list.push_back(new key_part_spec(field_name,0));
    lex->key_list.push_back(new Key(Key::UNIQUE,NullS,
				    lex->col_list));
    lex->col_list.empty();
  }

  if (default_value)
  {
    /*
      We allow specifying value for first TIMESTAMP column 
      altough it is silently ignored. This should be fixed in 4.1
      (by proper warning or real support for default values)
    */
    if (default_value->type() == Item::NULL_ITEM)
    {
      default_value=0;
      if ((type_modifier & (NOT_NULL_FLAG | AUTO_INCREMENT_FLAG)) ==
	  NOT_NULL_FLAG)
      {
	net_printf(&thd->net,ER_INVALID_DEFAULT,field_name);
	DBUG_RETURN(1);
      }
    }
#ifdef MYSQL41000
    else if (type_modifier & AUTO_INCREMENT_FLAG)
    {
      net_printf(&thd->net, ER_INVALID_DEFAULT, field_name);
      DBUG_RETURN(1);
    }
#endif
  }
  if (!(new_field=new create_field()))
    DBUG_RETURN(1);
  new_field->field=0;
  new_field->field_name=field_name;
#ifdef MYSQL41000
  new_field->def= default_value;
#else
  new_field->def= (type_modifier & AUTO_INCREMENT_FLAG ? 0 : default_value);
#endif
  new_field->flags= type_modifier;
  new_field->unireg_check= (type_modifier & AUTO_INCREMENT_FLAG ?
			    Field::NEXT_NUMBER : Field::NONE);
  new_field->decimals= decimals ? (uint) set_zone(atoi(decimals),0,
						  NOT_FIXED_DEC-1) : 0;
  new_field->sql_type=type;
  new_field->length=0;
  new_field->change=change;
  new_field->interval=0;
  new_field->pack_length=0;
  if (length && !(new_field->length= (uint) atoi(length)))
    length=0; /* purecov: inspected */
  uint sign_len=type_modifier & UNSIGNED_FLAG ? 0 : 1;

  if (new_field->length && new_field->decimals &&
      new_field->length < new_field->decimals+1 &&
      new_field->decimals != NOT_FIXED_DEC)
    new_field->length=new_field->decimals+1; /* purecov: inspected */

  switch (type) {
  case FIELD_TYPE_TINY:
    if (!length) new_field->length=3+sign_len;
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    break;
  case FIELD_TYPE_SHORT:
    if (!length) new_field->length=5+sign_len;
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    break;
  case FIELD_TYPE_INT24:
    if (!length) new_field->length=8+sign_len;
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    break;
  case FIELD_TYPE_LONG:
    if (!length) new_field->length=10+sign_len;
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    break;
  case FIELD_TYPE_LONGLONG:
    if (!length) new_field->length=20;
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    break;
  case FIELD_TYPE_STRING:
  case FIELD_TYPE_VAR_STRING:
  case FIELD_TYPE_NULL:
  case FIELD_TYPE_GEOMETRY:
    break;
  case FIELD_TYPE_DECIMAL:
    if (!length)
    {
      if ((new_field->length= new_field->decimals))
        new_field->length++;
      else
        new_field->length= 10;                  // Default length for DECIMAL
    }
    if (new_field->length < MAX_FIELD_WIDTH)	// Skip wrong argument
    {
      new_field->length+=sign_len;
      if (new_field->decimals)
	new_field->length++;
    }
    break;
  case FIELD_TYPE_BLOB:
  case FIELD_TYPE_TINY_BLOB:
  case FIELD_TYPE_LONG_BLOB:
  case FIELD_TYPE_MEDIUM_BLOB:
    if (default_value)				// Allow empty as default value
    {
      String str,*res;
      res=default_value->val_str(&str);
      if (res->length())
      {
	net_printf(&thd->net,ER_BLOB_CANT_HAVE_DEFAULT,field_name); /* purecov: inspected */
	DBUG_RETURN(1); /* purecov: inspected */
      }
      new_field->def=0;
    }
    new_field->flags|=BLOB_FLAG;
    break;
  case FIELD_TYPE_YEAR:
    if (!length || new_field->length != 2)
      new_field->length=4;			// Default length
    new_field->flags|= ZEROFILL_FLAG | UNSIGNED_FLAG;
    break;
  case FIELD_TYPE_FLOAT:
    /* change FLOAT(precision) to FLOAT or DOUBLE */
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    if (length && !decimals)
    {
      uint tmp_length=new_field->length;
      if (tmp_length > PRECISION_FOR_DOUBLE)
      {
	net_printf(&thd->net,ER_WRONG_FIELD_SPEC,field_name);
	DBUG_RETURN(1);
      }
      else if (tmp_length > PRECISION_FOR_FLOAT)
      {
	new_field->sql_type=FIELD_TYPE_DOUBLE;
	new_field->length=DBL_DIG+7;			// -[digits].E+###
      }
      else
	new_field->length=FLT_DIG+6;			// -[digits].E+##
      new_field->decimals= NOT_FIXED_DEC;
      break;
    }
    if (!length)
    {
      new_field->length =  FLT_DIG+6;
      new_field->decimals= NOT_FIXED_DEC;
    }
    break;
  case FIELD_TYPE_DOUBLE:
    allowed_type_modifier= AUTO_INCREMENT_FLAG;
    if (!length)
    {
      new_field->length = DBL_DIG+7;
      new_field->decimals=NOT_FIXED_DEC;
    }
    break;
  case FIELD_TYPE_TIMESTAMP:
    if (!length)
      new_field->length= 14;			// Full date YYYYMMDDHHMMSS
    else if (new_field->length != 19)
    {
      /*
        We support only even TIMESTAMP lengths less or equal than 14
        and 19 as length of 4.1 compatible representation.
      */
      new_field->length=((new_field->length+1)/2)*2; /* purecov: inspected */
      new_field->length= min(new_field->length,14); /* purecov: inspected */
    }
    new_field->flags|= ZEROFILL_FLAG | UNSIGNED_FLAG | NOT_NULL_FLAG;
    break;
  case FIELD_TYPE_DATE:				// Old date type
    if (protocol_version != PROTOCOL_VERSION-1)
      new_field->sql_type=FIELD_TYPE_NEWDATE;
    /* fall trough */
  case FIELD_TYPE_NEWDATE:
    new_field->length=10;
    break;
  case FIELD_TYPE_TIME:
    new_field->length=10;
    break;
  case FIELD_TYPE_DATETIME:
    new_field->length=19;
    break;
  case FIELD_TYPE_SET:
    {
      if (interval->count > sizeof(longlong)*8)
      {
	net_printf(&thd->net,ER_TOO_BIG_SET,field_name); /* purecov: inspected */
	DBUG_RETURN(1);				/* purecov: inspected */
      }
      new_field->pack_length=(interval->count+7)/8;
      if (new_field->pack_length > 4)
	new_field->pack_length=8;
      new_field->interval=interval;
      new_field->length=0;
      for (const char **pos=interval->type_names; *pos ; pos++)
      {
	new_field->length+=(uint) strip_sp((char*) *pos)+1;
      }
      new_field->length--;
      set_if_smaller(new_field->length,MAX_FIELD_WIDTH-1);
      if (default_value)
      {
	thd->cuted_fields=0;
	String str,*res;
	res=default_value->val_str(&str);
	(void) find_set(interval,res->ptr(),res->length());
	if (thd->cuted_fields)
	{
	  net_printf(&thd->net,ER_INVALID_DEFAULT,field_name);
	  DBUG_RETURN(1);
	}
      }
    }
    break;
  case FIELD_TYPE_ENUM:
    {
      new_field->interval=interval;
      new_field->pack_length=interval->count < 256 ? 1 : 2; // Should be safe
      new_field->length=(uint) strip_sp((char*) interval->type_names[0]);
      for (const char **pos=interval->type_names+1; *pos ; pos++)
      {
	uint length=(uint) strip_sp((char*) *pos);
	set_if_bigger(new_field->length,length);
      }
      set_if_smaller(new_field->length,MAX_FIELD_WIDTH-1);
      if (default_value)
      {
	String str,*res;
	res=default_value->val_str(&str);
	if (!find_enum(interval,res->ptr(),res->length()))
	{
	  net_printf(&thd->net,ER_INVALID_DEFAULT,field_name);
	  DBUG_RETURN(1);
	}
      }
      break;
    }
  }

  if (new_field->length >= MAX_FIELD_WIDTH ||
      (!new_field->length && !(new_field->flags & BLOB_FLAG) &&
       type != FIELD_TYPE_STRING && type != FIELD_TYPE_VAR_STRING))
  {
    net_printf(&thd->net,ER_TOO_BIG_FIELDLENGTH,field_name,
	       MAX_FIELD_WIDTH-1);		/* purecov: inspected */
    DBUG_RETURN(1);				/* purecov: inspected */
  }
  type_modifier&= AUTO_INCREMENT_FLAG;
  if ((~allowed_type_modifier) & type_modifier)
  {
    net_printf(&thd->net,ER_WRONG_FIELD_SPEC,field_name);
    DBUG_RETURN(1);
  }
  if (!new_field->pack_length)
    new_field->pack_length=calc_pack_length(new_field->sql_type ==
					    FIELD_TYPE_VAR_STRING ?
					    FIELD_TYPE_STRING :
					    new_field->sql_type,
					    new_field->length);
  lex->create_list.push_back(new_field);
  lex->last_field=new_field;
  DBUG_RETURN(0);
}

/* Store position for column in ALTER TABLE .. ADD column */

void store_position_for_column(const char *name)
{
  current_lex->last_field->after=my_const_cast(char*) (name);
}

bool
add_proc_to_list(THD* thd, Item *item)
{
  ORDER *order;
  Item	**item_ptr;

  if (!(order = (ORDER *) sql_alloc(sizeof(ORDER)+sizeof(Item*))))
    return 1;
  item_ptr = (Item**) (order+1);
  *item_ptr= item;
  order->item=item_ptr;
  order->free_me=0;
  thd->lex.proc_list.link_in_list((byte*) order,(byte**) &order->next);
  return 0;
}


/* Fix escaping of _, % and \ in database and table names (for ODBC) */

static void remove_escape(char *name)
{
  if (!*name)					// For empty DB names
    return;
  char *to;
#ifdef USE_MB
  char *strend=name+(uint) strlen(name);
#endif
  for (to=name; *name ; name++)
  {
#ifdef USE_MB
    int l;
/*    if ((l = ismbchar(name, name+MBMAXLEN))) { Wei He: I think it's wrong */
    if (use_mb(default_charset_info) &&
        (l = my_ismbchar(default_charset_info, name, strend)))
    {
	while (l--)
	    *to++ = *name++;
	name--;
	continue;
    }
#endif
    if (*name == '\\' && name[1])
      name++;					// Skip '\\'
    *to++= *name;
  }
  *to=0;
}

/****************************************************************************
** save order by and tables in own lists
****************************************************************************/


bool add_to_list(SQL_LIST &list,Item *item,bool asc)
{
  ORDER *order;
  Item	**item_ptr;
  DBUG_ENTER("add_to_list");
  if (!(order = (ORDER *) sql_alloc(sizeof(ORDER)+sizeof(Item*))))
    DBUG_RETURN(1);
  item_ptr = (Item**) (order+1);
  *item_ptr=item;
  order->item= item_ptr;
  order->asc = asc;
  order->free_me=0;
  order->used=0;
  list.link_in_list((byte*) order,(byte**) &order->next);
  DBUG_RETURN(0);
}


/*
  Add a table to list of used tables

  SYNOPSIS
    add_table_to_list()
    table		Table to add
    alias		alias for table (or null if no alias)
    table_options	A set of the following bits:
			TL_OPTION_UPDATING	Table will be updated
			TL_OPTION_FORCE_INDEX	Force usage of index
    lock_type		How table should be locked
    use_index		List of indexed used in USE INDEX
    ignore_index	List of indexed used in IGNORE INDEX

    RETURN
      0		Error
      #		Pointer to TABLE_LIST element added to the total table list
*/

TABLE_LIST *add_table_to_list(Table_ident *table, LEX_STRING *alias,
			      ulong table_options,
			      thr_lock_type lock_type,
			      List<String> *use_index,
			      List<String> *ignore_index)
{
  register TABLE_LIST *ptr;
  THD	*thd=current_thd;
  char *alias_str;
  DBUG_ENTER("add_table_to_list");

  if (!table)
    DBUG_RETURN(0);				// End of memory
  alias_str= alias ? alias->str : table->table.str;
  if (check_table_name(table->table.str,table->table.length) ||
      table->db.str && check_db_name(table->db.str))
  {
    net_printf(&thd->net,ER_WRONG_TABLE_NAME,table->table.str);
    DBUG_RETURN(0);
  }

  if (!alias)					/* Alias is case sensitive */
    if (!(alias_str=thd->memdup(alias_str,table->table.length+1)))
      DBUG_RETURN(0);
    
  if (!(ptr = (TABLE_LIST *) thd->calloc(sizeof(TABLE_LIST))))
    DBUG_RETURN(0);				/* purecov: inspected */
  if (table->db.str) 
  {
    ptr->db= table->db.str;
    ptr->db_length= table->db.length;
  }
  else if (thd->db)
  {
    ptr->db= thd->db;
    ptr->db_length= thd->db_length;
  }
  else
  {
    ptr->db= (char*) "";
    ptr->db_length= 0;
  }
    
  ptr->alias= alias_str;
  table_case_convert(table->table.str, table->table.length);
  ptr->real_name=table->table.str;
  ptr->real_name_length=table->table.length;
  ptr->lock_type= lock_type;
  ptr->updating=    test(table_options & TL_OPTION_UPDATING);
  ptr->force_index= test(table_options & TL_OPTION_FORCE_INDEX);
  if (use_index)
    ptr->use_index=(List<String> *) thd->memdup((gptr) use_index,
					       sizeof(*use_index));
  if (ignore_index)
    ptr->ignore_index=(List<String> *) thd->memdup((gptr) ignore_index,
						   sizeof(*ignore_index));

  /* check that used name is unique */
  if (lock_type != TL_IGNORE)
  {
    for (TABLE_LIST *tables=(TABLE_LIST*) thd->lex.select->table_list.first ;
	 tables ;
	 tables=tables->next)
    {
      if (!strcmp(alias_str,tables->alias) && !strcmp(ptr->db, tables->db))
      {
	net_printf(&thd->net,ER_NONUNIQ_TABLE,alias_str); /* purecov: tested */
	DBUG_RETURN(0);				/* purecov: tested */
      }
    }
  }
  thd->lex.select->table_list.link_in_list((byte*) ptr,(byte**) &ptr->next);
  DBUG_RETURN(ptr);
}

/*
  Set lock for all tables in current select level

  SYNOPSIS:
    set_lock_for_tables()
    lock_type			Lock to set for tables

  NOTE:
    If lock is a write lock, then tables->updating is set 1
    This is to get tables_ok to know that the table is updated by the
    query
*/

void set_lock_for_tables(thr_lock_type lock_type)
{
  THD	*thd=current_thd;
  bool for_update= lock_type >= TL_READ_NO_INSERT;
  DBUG_ENTER("set_lock_for_tables");
  DBUG_PRINT("enter", ("lock_type: %d  for_update: %d", lock_type,
		       for_update));

  for (TABLE_LIST *tables= (TABLE_LIST*) thd->lex.select->table_list.first ;
       tables ;
       tables=tables->next)
  {
    tables->lock_type= lock_type;
    tables->updating=  for_update;
  }
  DBUG_VOID_RETURN;
}


/*
** This is used for UNION to create a new table list of all used tables
** The table_list->table entry in all used tables are set to point
** to the entries in this list.
*/

static bool create_total_list(THD *thd, LEX *lex,
			      TABLE_LIST **result, bool skip_first)
{
  /* Handle the case when we are not using union */
  if (!lex->select_lex.next)
  {
    *result= (TABLE_LIST*) lex->select_lex.table_list.first;
    return 0;
  }

  /* We should skip first table if SQL command is SQLCOM_CREATE_TABLE */
  SELECT_LEX *sl;
  TABLE_LIST **new_table_list= result, *aux;

  *new_table_list=0;				// end result list
  for (sl= &lex->select_lex; sl; sl=sl->next)
  {
    if (sl->order_list.first && sl->next && !sl->braces)
    {
      net_printf(&thd->net,ER_WRONG_USAGE,"UNION","ORDER BY");
      return 1;
    }
    if ((aux= (TABLE_LIST*) sl->table_list.first))
    {
      TABLE_LIST *next;
      for (; aux; aux=next)
      {
	TABLE_LIST *cursor= *result;
	if (skip_first && cursor)
	  cursor= cursor->next;
	next= aux->next;
	for ( ; cursor; cursor=cursor->next)
	  if (!strcmp(cursor->db,aux->db) &&
	      !strcmp(cursor->real_name,aux->real_name) &&
	      !strcmp(cursor->alias, aux->alias))
	    break;
	if (!cursor)
	{
	  /* Add not used table to the total table list */
	  if (!(cursor = (TABLE_LIST *) thd->memdup((char*) aux,
						    sizeof(*aux))))
	  {
	    send_error(&thd->net,0);
	    return 1;
	  }
	  *new_table_list= cursor;
	  new_table_list= &cursor->next;
	  *new_table_list=0;			// end result list
	}
	else
	  aux->shared=1;			// Mark that it's used twice
	aux->table= my_reinterpret_cast(TABLE *) (cursor);
      }
    }
  }
  return 0;
}


void add_join_on(TABLE_LIST *b,Item *expr)
{
  if (expr)
  {
    if (!b->on_expr)
      b->on_expr=expr;
    else
    {
      // This only happens if you have both a right and left join
      b->on_expr=new Item_cond_and(b->on_expr,expr);
    }
    b->on_expr->top_level_item();
  }
}


/*
  Mark that we have a NATURAL JOIN between two tables

  SYNOPSIS
    add_join_natural()
    a			Table to do normal join with
    b			Do normal join with this table
  
  IMPLEMENTATION
    This function just marks that table b should be joined with a.
    The function setup_cond() will create in b->on_expr a list
    of equal condition between all fields of the same name.

    SELECT * FROM t1 NATURAL LEFT JOIN t2
     <=>
    SELECT * FROM t1 LEFT JOIN t2 ON (t1.i=t2.i and t1.j=t2.j ... )
*/

void add_join_natural(TABLE_LIST *a,TABLE_LIST *b)
{
  b->natural_join=a;
}

	/* Check if name is used in table list */

bool check_dup(const char *db, const char *name, TABLE_LIST *tables)
{
  for (; tables ; tables=tables->next)
    if (!strcmp(name,tables->real_name) && !strcmp(db,tables->db))
      return 1;
  return 0;
}


/*
  Reload/resets privileges and the different caches
*/

bool reload_acl_and_cache(THD *thd, ulong options, TABLE_LIST *tables)
{
  bool result=0;
  bool error_already_sent=0;
  select_errors=0;				/* Write if more errors */
  if (options & REFRESH_GRANT)
  {
    acl_reload(thd);
    grant_reload(thd);
    if (mqh_used)
      reset_mqh(thd,(LEX_USER *) NULL,true);
  }
  if (options & REFRESH_LOG)
  {
    /*
      Flush the normal query log, the update log, the binary log,
      the slow query log, and the relay log (if it exists).
    */
    mysql_log.new_file(1);
    mysql_update_log.new_file(1);
    mysql_bin_log.new_file(1);
    mysql_slow_log.new_file(1);
    pthread_mutex_lock(&LOCK_active_mi);
    rotate_relay_log(active_mi);
    pthread_mutex_unlock(&LOCK_active_mi);

    if (ha_flush_logs())
      result=1;
    if (flush_error_log())
      result=1;
  }
#ifdef HAVE_QUERY_CACHE
  if (options & REFRESH_QUERY_CACHE_FREE)
  {
    query_cache.pack();				// FLUSH QUERY CACHE
    options &= ~REFRESH_QUERY_CACHE; //don't flush all cache, just free memory
  }
  if (options & (REFRESH_TABLES | REFRESH_QUERY_CACHE))
  {
    query_cache.flush();			// RESET QUERY CACHE
  }
#endif /*HAVE_QUERY_CACHE*/
  if (options & (REFRESH_TABLES | REFRESH_READ_LOCK))
  {
    if ((options & REFRESH_READ_LOCK) && thd)
    {
      if (lock_global_read_lock(thd))
	return 1;
    }
    result=close_cached_tables(thd,(options & REFRESH_FAST) ? 0 : 1, tables);
  }
  if (options & REFRESH_HOSTS)
    hostname_cache_refresh();
  if (options & REFRESH_STATUS)
    refresh_status();
  if (options & REFRESH_THREADS)
    flush_thread_cache();
  if (options & REFRESH_MASTER)
    if (reset_master(thd))
      result=1;
#ifdef OPENSSL
   if (options & REFRESH_DES_KEY_FILE)
   {
     if (des_key_file)
       result=load_des_key_file(des_key_file);
   }
#endif
 if (options & REFRESH_SLAVE)
 {
   pthread_mutex_lock(&LOCK_active_mi);
   if (reset_slave(thd, active_mi))
   {
     result=1;
     /*
       reset_slave() sends error itself.
       If it didn't, one would either change reset_slave()'s prototype, to
       pass *errorcode and *errmsg to it when it's called or
       change reset_slave to use my_error() to register the error.
     */
     error_already_sent=1;
   }
   pthread_mutex_unlock(&LOCK_active_mi);
 }
 if (options & REFRESH_USER_RESOURCES)
   reset_mqh(thd,(LEX_USER *) NULL);

 if (thd && !error_already_sent)
 {
   if (result)
     send_error(&thd->net,0);
   else
     send_ok(&thd->net);
 }

 return result;
}


/*
  kill on thread

  SYNOPSIS
    kill_one_thread()
    thd			Thread class
    id			Thread id

  NOTES
    This is written such that we have a short lock on LOCK_thread_count
*/

void kill_one_thread(THD *thd, ulong id)
{
  THD *tmp;
  uint error=ER_NO_SUCH_THREAD;
  VOID(pthread_mutex_lock(&LOCK_thread_count)); // For unlink from list
  I_List_iterator<THD> it(threads);
  while ((tmp=it++))
  {
    if (tmp->thread_id == id)
    {
      pthread_mutex_lock(&tmp->LOCK_delete);	// Lock from delete
      break;
    }
  }
  VOID(pthread_mutex_unlock(&LOCK_thread_count));
  if (tmp)
  {
    if ((thd->master_access & SUPER_ACL) ||
	!strcmp(thd->user,tmp->user))
    {
      tmp->awake(1 /*prepare to die*/);
      error=0;
    }
    else
      error=ER_KILL_DENIED_ERROR;
    pthread_mutex_unlock(&tmp->LOCK_delete);
  }

  if (!error)
    send_ok(&thd->net);
  else
    net_printf(&thd->net,error,id);
}

/* Clear most status variables */

static void refresh_status(void)
{
  pthread_mutex_lock(&THR_LOCK_keycache);
  pthread_mutex_lock(&LOCK_status);
  for (struct show_var_st *ptr=status_vars; ptr->name; ptr++)
  {
    if (ptr->type == SHOW_LONG)
      *(ulong*) ptr->value=0;
  }
  pthread_mutex_unlock(&LOCK_status);
  pthread_mutex_unlock(&THR_LOCK_keycache);
}


	/* If pointer is not a null pointer, append filename to it */

static bool append_file_to_dir(THD *thd, const char **filename_ptr,
			       const char *table_name)
{
  char buff[FN_REFLEN],*ptr, *end;
  if (!*filename_ptr)
    return 0;					// nothing to do

  /* Check that the filename is not too long and it's a hard path */
  if (strlen(*filename_ptr)+strlen(table_name) >= FN_REFLEN-1 ||
      !test_if_hard_path(*filename_ptr))
  {
    my_error(ER_WRONG_TABLE_NAME, MYF(0), *filename_ptr);
    return 1;
  }
  /* Fix is using unix filename format on dos */
  strmov(buff,*filename_ptr);
  end=convert_dirname(buff, *filename_ptr, NullS);
  if (!(ptr=thd->alloc((uint) (end-buff)+(uint) strlen(table_name)+1)))
    return 1;					// End of memory
  *filename_ptr=ptr;
  strxmov(ptr,buff,table_name,NullS);
  return 0;
}

/*
  Check if the select is a simple select (not an union)

  SYNOPSIS
    check_simple_select()

  RETURN VALUES
    0	ok
    1	error	; In this case the error messege is sent to the client
*/

bool check_simple_select()
{
  THD *thd= current_thd;
  if (thd->lex.select != &thd->lex.select_lex)
  {
    char command[80];
    strmake(command, thd->lex.yylval->symbol.str,
	    min(thd->lex.yylval->symbol.length, sizeof(command)-1));
    net_printf(&thd->net, ER_CANT_USE_OPTION_HERE, command);
    return 1;
  }
  return 0;
}