sql_parse.cc

/* Copyright (C) 2000 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 MEM_ROOT_BLOCK_SIZE       8192
#define MEM_ROOT_PREALLOC         8192
#define TRANS_MEM_ROOT_BLOCK_SIZE 4096
#define TRANS_MEM_ROOT_PREALLOC   4096

extern int yyparse(void *thd);
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(THD *thd, 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 remove_escape(char *name);
static void refresh_status(void);
static bool append_file_to_dir(THD *thd, char **filename_ptr,
			       char *table_name);

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",
  "Prepare", "Prepare Execute", "Long Data", "Close stmt"
};

static char empty_c_string[1]= {0};		// Used for not defined 'db'

#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;
}


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(thd, 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 = 1;
    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(thd, 0, NullS);		// Out of memory
      return_val=1;
      goto end;
    }
  }
  thd->user_connect=uc;
end:
  (void) pthread_mutex_unlock(&LOCK_user_conn);
  return return_val;

}


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

static int check_user(THD *thd,enum_server_command command, const char *user,
		       const char *passwd, const char *db, bool check_count,
                       bool do_send_error, char* crypted_scramble,int stage,
                       bool had_password,uint *cur_priv_version,
                       ACL_USER** hint_user)
{
  thd->db=0;
  thd->db_length=0;
  USER_RESOURCES ur;

  /* We shall avoid dupplicate user allocations here */
  if (!(thd->user))
    if (!(thd->user = my_strdup(user, MYF(0))))
    {
      send_error(thd,ER_OUT_OF_RESOURCES);
      return 1;
    }
  thd->master_access=acl_getroot(thd, thd->host, thd->ip, thd->user,
				 passwd, thd->scramble, &thd->priv_user,
				 protocol_version == 9 ||
				 !(thd->client_capabilities &
				   CLIENT_LONG_PASSWORD),&ur,crypted_scramble,
                                   stage,cur_priv_version,hint_user);

  DBUG_PRINT("info",
	     ("Capabilities: %d  packet_length: %d  Host: '%s'  User: '%s'  Using password: %s  Access: %u  db: '%s'",
	      thd->client_capabilities, thd->max_client_packet_length,
	      thd->host_or_ip, thd->priv_user,
	      had_password ? "yes": "no",
	      thd->master_access, thd->db ? thd->db : "*none*"));

  /* in case we're going to retry we should not send error message at this point */
  if (thd->master_access & NO_ACCESS)
  {
    if (do_send_error)
    {
      net_printf(thd, ER_ACCESS_DENIED_ERROR,
      	       thd->user,
	       thd->host_or_ip,
	       had_password ? ER(ER_YES) : ER(ER_NO));
      mysql_log.write(thd,COM_CONNECT,ER(ER_ACCESS_DENIED_ERROR),
		    thd->user,
		    thd->host_or_ip,
		    had_password ? ER(ER_YES) : ER(ER_NO));
      return(1);					// Error already given
    }
    else
      return(-1); // do not report error in special handshake
  }

  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(thd, 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) &&
      get_or_create_user_conn(thd,user,thd->host_or_ip,&ur))
    return -1;
  if (thd->user_connect && thd->user_connect->user_resources.connections &&
      check_for_max_user_connections(thd, 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;
  }
  else
    send_ok(thd);				// Ready to handle questions
  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,system_charset_info,max_connections,
		   0,0,
		   (hash_get_key) get_key_conn, (hash_free_key) free_user,
		   0);
}


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

  if (max_user_connections &&
      (max_user_connections <=  (uint) uc->connections))
  {
    net_printf(thd,ER_TOO_MANY_USER_CONNECTIONS, uc->user);
    error=1;
    goto end;
  }
  uc->connections++;
  if (uc->user_resources.connections &&
      uc->conn_per_hour++ >= uc->user_resources.connections)
  {
    net_printf(thd, ER_USER_LIMIT_REACHED, uc->user,
	       "max_connections",
	       (long) uc->user_resources.connections);
    error=1;
  }
end:
  DBUG_RETURN(error);
}


static void decrease_user_connections(USER_CONN *uc)
{
  DBUG_ENTER("decrease_user_connections");
  if ((uc->connections && !--uc->connections) && !mqh_used)
  {
    /* Last connection for user; Delete it */
    (void) pthread_mutex_lock(&LOCK_user_conn);
    (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_UPDATE_MULTI]=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, 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, 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=false)
{

  (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))
      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;
    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);
      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+64],*end;
    int client_flags = CLIENT_LONG_FLAG | CLIENT_CONNECT_WITH_DB |
                       CLIENT_PROTOCOL_41 | CLIENT_SECURE_CONNECTION;

    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;

    // At this point we write connection message and read reply
    if (net_write_command(net,(uchar) protocol_version, "", 0, 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. */
    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;

  /* We can get only old hash at this point */
  if (passwd[0] && strlen(passwd)!=SCRAMBLE_LENGTH)
      return ER_HANDSHAKE_ERROR;

  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;

  char prepared_scramble[SCRAMBLE41_LENGTH+4]; /* Buffer for scramble and hash */

  ACL_USER* cached_user;
  uint cur_priv_version;

  /* Simple connect only for old clients. New clients always use secure auth */
  bool simple_connect=(!(thd->client_capabilities & CLIENT_SECURE_CONNECTION));

  /* Store information if we used password. passwd will be dammaged */
  bool using_password=test(passwd[0]);

  /* Check user permissions. If password failure we'll get scramble back */
  if (check_user(thd,COM_CONNECT, user, passwd, db, 1, simple_connect,
      prepared_scramble,0,using_password,&cur_priv_version,&cached_user)<0)
  {
    /* If The client is old we just have to return error */
    if (simple_connect)
      return -1;

    /* Store current used and database as they are erased with next packet */

    char tmp_user[USERNAME_LENGTH+1];
    char tmp_db[NAME_LEN+1];

    tmp_user[0]=0;
    if (user)
      strmake(tmp_user,user,USERNAME_LENGTH);

    tmp_db[0]=0;  
    if (db)
      strmake(tmp_db,db,NAME_LEN);

    /* Write hash and encrypted scramble to client */
    if (my_net_write(net,prepared_scramble,SCRAMBLE41_LENGTH+4)
        || net_flush(net))
      {
        inc_host_errors(&thd->remote.sin_addr);
        return ER_HANDSHAKE_ERROR;
      }
    /* Reading packet back */
    if ((pkt_len=my_net_read(net)) == packet_error)
      {
        inc_host_errors(&thd->remote.sin_addr);
        return ER_HANDSHAKE_ERROR;
      }
    /* We have to get very specific packet size  */
    if (pkt_len!=SCRAMBLE41_LENGTH)
      {
        inc_host_errors(&thd->remote.sin_addr);
        return ER_HANDSHAKE_ERROR;
      }
    /* Final attempt to check the user based on reply */
    if (check_user(thd,COM_CONNECT, tmp_user, (char*)net->read_pos,
        tmp_db, 1, 1,prepared_scramble,1,using_password,&cur_priv_version,
        &cached_user))
      return -1;
  }
  thd->password=using_password;
  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)
  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(thd,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;
    }

    if ((ulong) thd->variables.max_join_size == (ulonglong) 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, MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC);
    init_sql_alloc(&thd->transaction.mem_root,
		   TRANS_MEM_ROOT_BLOCK_SIZE, TRANS_MEM_ROOT_PREALLOC);
    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 && net->report_error)
    {
      if (!thd->killed && thd->variables.log_warnings)
	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(thd,net->last_errno,NullS);
      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)
  sigset_t set;
  VOID(sigemptyset(&set));			// Get mask in use
  VOID(pthread_sigmask(SIG_UNBLOCK,&set,&thd->block_signals));


#endif

  if ((ulong) thd->variables.max_join_size == (ulonglong) 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, MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC);
  init_sql_alloc(&thd->transaction.mem_root,
		 TRANS_MEM_ROOT_BLOCK_SIZE, TRANS_MEM_ROOT_PREALLOC);
  while (fgets(buff, thd->net.max_packet, file))
  {
    uint length=(uint) strlen(buff);
    while (length && (my_isspace(system_charset_info, 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
}

    /* This works because items are allocated with sql_alloc() */

void free_items(Item *item)
{
  for (; 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;
  remove_escape(table_list->real_name);

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

  if (!db || check_db_name(db))
  {
    net_printf(thd,ER_WRONG_DB_NAME, db ? db : "NULL");
    goto err;
  }
  if (check_access(thd, SELECT_ACL, db, &table_list->grant.privilege))
    goto err;
  if (grant_option && check_grant(thd, SELECT_ACL, table_list))
    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;
  thd->clear_error();				// Clear error message

  net_new_transaction(net);
  if ((packet_length=my_net_read(net)) == packet_error)
  {
     DBUG_PRINT("info",("Got error reading command from socket %s",
			vio_description(net->vio) ));
    return TRUE;
  }
  else
  {
    packet=(char*) net->read_pos;
    command = (enum enum_server_command) (uchar) packet[0];
    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);
    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); // 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;
    thd->user=NULL; /* Needed for check_user to allocate new user */
    char *save_priv_user=   thd->priv_user;
    char *save_db=	    thd->db;
    USER_CONN *save_uc=     thd->user_connect;
    bool simple_connect;
    bool using_password;

    ulong pkt_len=0; /* Length of reply packet */

    /* Small check for incomming packet */

    if ((uint) ((uchar*) db - net->read_pos) > packet_length)
      goto restore_user_err;

    /* Now we shall basically perform authentication again */

     /* We can get only old hash at this point */
    if (passwd[0] && strlen(passwd)!=SCRAMBLE_LENGTH)
      goto restore_user_err;

    char prepared_scramble[SCRAMBLE41_LENGTH+4];/* Buffer for scramble,hash */
    ACL_USER* cached_user;                      /* Cached user */
    uint cur_priv_version;                      /* Cached grant version */

    /* Simple connect only for old clients. New clients always use sec. auth*/
    simple_connect=(!(thd->client_capabilities & CLIENT_SECURE_CONNECTION));

    /* Store information if we used password. passwd will be dammaged */
    using_password=test(passwd[0]);

    if (simple_connect) /* Restore scramble for old clients */
      memcpy(thd->scramble,thd->old_scramble,9);

    /*
     Check user permissions. If password failure we'll get scramble back
     Do not retry if we already have sent error (result>0)
    */
    if (check_user(thd,COM_CHANGE_USER, user, passwd, db, 0, simple_connect,
        prepared_scramble,0,using_password,&cur_priv_version,&cached_user)<0)
    {
      /* If The client is old we just have to have auth failure */
      if (simple_connect)
        goto restore_user; /* Error is already reported */

      /* Store current used and database as they are erased with next packet */

      char tmp_user[USERNAME_LENGTH+1];
      char tmp_db[NAME_LEN+1];

      if (user)
      {
        strncpy(tmp_user,user,USERNAME_LENGTH+1);
        /* Extra safety if we have too long data */
        tmp_user[USERNAME_LENGTH]=0;
      }
      else
        tmp_user[0]=0;
      if (db)
      {
        strncpy(tmp_db,db,NAME_LEN+1);
        tmp_db[NAME_LEN]=0;
      }
      else
        tmp_db[0]=0;

      /* Write hash and encrypted scramble to client */
      if (my_net_write(net,prepared_scramble,SCRAMBLE41_LENGTH+4)
        || net_flush(net))
        goto restore_user_err;

      /* Reading packet back */
      if ((pkt_len=my_net_read(net)) == packet_error)
        goto restore_user_err;

      /* We have to get very specific packet size  */
      if (pkt_len!=SCRAMBLE41_LENGTH)
        goto restore_user;

      /* Final attempt to check the user based on reply */
      if (check_user(thd,COM_CONNECT, tmp_user, (char*)net->read_pos,
          tmp_db, 0, 1,prepared_scramble,1,using_password,&cur_priv_version,
          &cached_user))
        goto restore_user;
    }
    /* Finally we've authenticated new user */
    if (max_connections && save_uc)
      decrease_user_connections(save_uc);
    x_free((gptr) save_db);
    x_free((gptr) save_user);
    thd->password=using_password;
    break;

    /* Bad luck  we shall restore old user */
    restore_user_err:
    send_error(thd, ER_UNKNOWN_COM_ERROR);

    restore_user:
    x_free(thd->user);
    x_free(thd->db);
    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;
    break;
  }

  case COM_EXECUTE:
  {
    mysql_stmt_execute(thd, packet);
    break;
  }
  case COM_LONG_DATA:
  {
    mysql_stmt_get_longdata(thd, packet, packet_length);
    break;
  }
  case COM_PREPARE:
  {
    mysql_stmt_prepare(thd, packet, packet_length);
    break;
  }
  case COM_CLOSE_STMT:
  {
    mysql_stmt_free(thd, packet);
    break;
  }
  case COM_QUERY:
  {
    if (alloc_query(thd, packet, packet_length))
      break;					// fatal error is set
    mysql_log.write(thd,command,"%s",thd->query);
    DBUG_PRINT("query",("%s",thd->query));
    mysql_parse(thd,thd->query, thd->query_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,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(thd,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);
    remove_escape(table_list.real_name);	// This can't have wildcards

    if (check_access(thd,SELECT_ACL,table_list.db,&thd->col_access))
      break;
    table_list.grant.privilege=thd->col_access;
    if (grant_option && check_grant(thd,SELECT_ACL,&table_list,2))
      break;
    mysqld_list_fields(thd,&table_list,fields);
    free_items(thd->free_list);
    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
    {
      statistic_increment(com_stat[SQLCOM_CREATE_DB],&LOCK_status);
      char *db=thd->strdup(packet);
      // null test to handle EOM
      if (!db || !strip_sp(db) || check_db_name(db))
      {
	net_printf(thd,ER_WRONG_DB_NAME, db ? db : "NULL");
	break;
      }
      if (lower_case_table_names)
	my_casedn_str(system_charset_info, db);
      if (check_access(thd,CREATE_ACL,db,0,1))
	break;
      mysql_log.write(thd,command,packet);
      mysql_create_db(thd,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);
      // null test to handle EOM
      if (!db || !strip_sp(db) || check_db_name(db))
      {
	net_printf(thd,ER_WRONG_DB_NAME, db ? db : "NULL");
	break;
      }
      if (lower_case_table_names)
	my_casedn_str(system_charset_info, db);
      if (thd->locked_tables || thd->active_transaction())
      {
	send_error(thd,ER_LOCK_OR_ACTIVE_TRANSACTION);
	break;
      }
      mysql_log.write(thd,command,db);
      mysql_rm_db(thd,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 */
      kill_zombie_dump_threads(slave_server_id = uint4korr(packet+6));
      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);
      if (reload_acl_and_cache(thd, options, (TABLE_LIST*) 0))
	send_error(thd,0);
      else
	send_eof(thd);
      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(thd);
#ifdef __WIN__
    sleep(1);					// must wait after eof()
#endif
#ifndef OS2
    send_eof(thd);				// 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 (lCurMemory)				// Using SAFEMALLOC
      sprintf(strend(buff), "  Memory in use: %ldK  Max memory used: %ldK",
	      (lCurMemory+1023L)/1024L,(lMaxMemory+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(thd);				// 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(thd);
    break;
  case COM_SLEEP:
  case COM_CONNECT:				// Impossible here
  case COM_TIME:				// Impossible from client
  case COM_DELAYED_INSERT:
  default:
    send_error(thd, 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(thd,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;
  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);
}


/*
  Read query from packet and store in thd->query
  Used in COM_QUERY and COM_PREPARE

  DESCRIPTION
    Sets the following THD variables:
      query
      query_length

  RETURN VALUES
    0	ok
    1	error;  In this case thd->fatal_error is set
*/

bool alloc_query(THD *thd, char *packet, ulong packet_length)
{
  packet_length--;				// Remove end null
  /* Remove garage at start and end of query */
  while (my_isspace(system_charset_info,packet[0]) && packet_length > 0)
  {
    packet++;
    packet_length--;
  }
  char *pos=packet+packet_length;		// Point at end null
  while (packet_length > 0 &&
	 (pos[-1] == ';' || my_isspace(system_charset_info,pos[-1])))
  {
    pos--;
    packet_length--;
  }
  /* We must allocate some extra memory for query cache */
  if (!(thd->query= (char*) thd->memdup_w_gap((gptr) (packet),
					      packet_length,
					      thd->db_length+2)))
    return 1;
  thd->query[packet_length]=0;
  thd->query_length= packet_length;
  thd->packet.shrink(thd->variables.net_buffer_length);// Reclaim some memory

  if (!(specialflag & SPECIAL_NO_PRIOR))
    my_pthread_setprio(pthread_self(),QUERY_PRIOR);
  return 0;
}

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

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

  /*
    Reset warning count for each query that uses tables
    A better approach would be to reset this for any commands
    that is not a SHOW command or a select that only access local
    variables, but for now this is probably good enough.
  */
  if (tables || &lex->select_lex != lex->all_selects_list)
    mysql_reset_errors(thd);
  /*
    Save old warning count to be able to send to client how many warnings we
    got
  */
  thd->old_total_warn_count= thd->total_warn_count;

  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 (table_rules_on && tables && !tables_ok(thd,tables))
      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
  }

  /*
    TODO: make derived tables processing 'inside' SELECT processing.
    TODO: solve problem with depended derived tables in subselects
  */
  if (lex->derived_tables)
  {
    for (SELECT_LEX *sl= lex->all_selects_list;
	 sl;
	 sl= sl->next_select_in_list())
      for (TABLE_LIST *cursor= sl->get_table_list();
	   cursor;
	   cursor= cursor->next)
	if (cursor->derived && (res=mysql_derived(thd, lex,
						  (SELECT_LEX_UNIT *)
						  cursor->derived,
						  cursor)))
	{
	  if (res < 0 || thd->net.report_error)
	    send_error(thd,thd->killed ? ER_SERVER_SHUTDOWN : 0);
	  DBUG_VOID_RETURN;
	}
  }
  if ((&lex->select_lex != lex->all_selects_list &&
       lex->unit.create_total_list(thd, lex, &tables)) ||
      (table_rules_on && tables && thd->slave_thread &&
       !tables_ok(thd,tables)))
    DBUG_VOID_RETURN;

  statistic_increment(com_stat[lex->sql_command],&LOCK_status);
  switch (lex->sql_command) {
  case SQLCOM_SELECT:
  {
    select_result *result=lex->result;
    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
    }

    unit->offset_limit_cnt= (ha_rows) unit->global_parameters->offset_limit;
    unit->select_limit_cnt= (ha_rows) (unit->global_parameters->select_limit+
      unit->global_parameters->offset_limit);
    if (unit->select_limit_cnt <
	(ha_rows) unit->global_parameters->select_limit)
      unit->select_limit_cnt= HA_POS_ERROR;		// no limit
    if (unit->select_limit_cnt == HA_POS_ERROR)
      select_lex->options&= ~OPTION_FOUND_ROWS;

    if (!(res=open_and_lock_tables(thd,tables)))
    {
      if (lex->describe)
      {
	if (!(result= new select_send()))
	{
	  send_error(thd, ER_OUT_OF_RESOURCES);
	  DBUG_VOID_RETURN;
	}
	else
	  thd->send_explain_fields(result);
	fix_tables_pointers(lex->all_selects_list);
	res= mysql_explain_union(thd, &thd->lex.unit, result);
	MYSQL_LOCK *save_lock= thd->lock;
	thd->lock= (MYSQL_LOCK *)0;
	result->send_eof();
	thd->lock= save_lock;
      }
      else
      {
	if (!result)
	{
	  if (!(result=new select_send()))
	  {
	    res= -1;
#ifdef DELETE_ITEMS
	    delete select_lex->having;
	    delete select_lex->where;
#endif
	    break;
	  }
	}
	query_cache_store_query(thd, tables);
	res=handle_select(thd, lex, result);
      }
    }
    break;
  }
  case SQLCOM_DO:
    res=mysql_do(thd, *lex->insert_list);
    break;

  case SQLCOM_EMPTY_QUERY:
    send_ok(thd);
    break;

  case SQLCOM_HELP:
    res= mysqld_help(thd,lex->help_arg);
    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_WARNS:
  {
    res= mysqld_show_warnings(thd, (ulong)
			      ((1L << (uint) MYSQL_ERROR::WARN_LEVEL_NOTE) |
			       (1L << (uint) MYSQL_ERROR::WARN_LEVEL_WARN)));
    break;
  }
  case SQLCOM_SHOW_ERRORS:
  {
    res= mysqld_show_warnings(thd, (ulong)
			      (1L << (uint) MYSQL_ERROR::WARN_LEVEL_ERROR));
    break;
  }
  case SQLCOM_SHOW_NEW_MASTER:
  {
    if (check_global_access(thd, REPL_SLAVE_ACL))
      goto error;
#ifndef WORKING_NEW_MASTER
    net_printf(thd, 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;
  }
  case SQLCOM_CHANGE_MASTER:
  {
    if (check_global_access(thd, SUPER_ACL))
      goto error;
    LOCK_ACTIVE_MI;
    res = change_master(thd,active_mi);
    UNLOCK_ACTIVE_MI;
    break;
  }
  case SQLCOM_SHOW_SLAVE_STAT:
  {
    if (check_global_access(thd, SUPER_ACL))
      goto error;
    LOCK_ACTIVE_MI;
    res = show_master_info(thd,active_mi);
    UNLOCK_ACTIVE_MI;
    break;
  }
  case SQLCOM_SHOW_MASTER_STAT:
  {
    if (check_global_access(thd, SUPER_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;

#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

  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;
    }
    if (strlen(tables->real_name) > NAME_LEN)
    {
      net_printf(thd,ER_WRONG_TABLE_NAME,tables->real_name);
      break;
    }
    LOCK_ACTIVE_MI;
    // fetch_master_table will send the error to the client on failure
    if (!fetch_master_table(thd, tables->db, tables->real_name,
			    active_mi, 0))
    {
      send_ok(thd);
    }
    UNLOCK_ACTIVE_MI;
    break;
  }
  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;
    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, 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) &&
	  find_real_table_in_list(tables->next, tables->db, tables->real_name))
      {
	net_printf(thd,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
      }
      unit->offset_limit_cnt= select_lex->offset_limit;
      unit->select_limit_cnt= select_lex->select_limit+
	select_lex->offset_limit;
      if (unit->select_limit_cnt < select_lex->select_limit)
	unit->select_limit_cnt= 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,0,0,0); // do logging
      if (!res)
	send_ok(thd);
    }
    break;
  }
  case SQLCOM_CREATE_INDEX:
    if (!tables->db)
      tables->db=thd->db;
    if (check_access(thd,INDEX_ACL,tables->db,&tables->grant.privilege))
      goto error; /* purecov: inspected */
    if (grant_option && check_grant(thd,INDEX_ACL,tables))
      goto error;
    if (end_active_trans(thd))
      res= -1;
    else
      res = mysql_create_index(thd, tables, lex->key_list);
    break;

  case SQLCOM_SLAVE_START:
  {
    LOCK_ACTIVE_MI;
    start_slave(thd,active_mi,1 /* net report*/);
    UNLOCK_ACTIVE_MI;
    break;
  }
  case SQLCOM_SLAVE_STOP:
  {
    LOCK_ACTIVE_MI;
    stop_slave(thd,active_mi,1/* net report*/);
    UNLOCK_ACTIVE_MI;
    break;
  }
  case SQLCOM_ALTER_TABLE:
#if defined(DONT_ALLOW_SHOW_COMMANDS)
    send_error(thd,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,ER_WRONG_TABLE_NAME,lex->name);
	res=0;
	break;
      }
      if (!tables->db)
	tables->db=thd->db;
      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 (!tables->db)
	tables->db=thd->db;
      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,tables))
	    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,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,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;
      create_info.table_charset=default_charset_info;
      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_access(thd,UPDATE_ACL,tables->db,&tables->grant.privilege))
      goto error;
    if (grant_option && check_grant(thd,UPDATE_ACL,tables))
      goto error;
    if (select_lex->item_list.elements != lex->value_list.elements)
    {
      send_error(thd,ER_WRONG_VALUE_COUNT);
      DBUG_VOID_RETURN;
    }
    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);
    if (thd->net.report_error)
      res= -1;
    break;
  case SQLCOM_UPDATE_MULTI:
    if (check_access(thd,UPDATE_ACL,tables->db,&tables->grant.privilege))
      goto error;
    if (grant_option && check_grant(thd,UPDATE_ACL,tables))
      goto error;
    if (select_lex->item_list.elements != lex->value_list.elements)
    {
      send_error(thd,ER_WRONG_VALUE_COUNT);
      DBUG_VOID_RETURN;
    }
    {
      multi_update  *result;
      uint table_count;
      TABLE_LIST *auxi;
      const char *msg=0;

      for (auxi= (TABLE_LIST*) tables, table_count=0 ; auxi ; auxi=auxi->next)
	table_count++;

      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, ER_WRONG_USAGE, "UPDATE", msg);
	res= 1;
	break;
      }

      tables->grant.want_privilege=(SELECT_ACL & ~tables->grant.privilege);
      if ((res=open_and_lock_tables(thd,tables)))
	break;
      unit->select_limit_cnt= HA_POS_ERROR;
      if (!setup_fields(thd,tables,select_lex->item_list,1,0,0) &&
	  !setup_fields(thd,tables,lex->value_list,0,0,0) &&
	  !thd->fatal_error &&
	  (result=new multi_update(thd,tables,select_lex->item_list,
				   lex->duplicates, table_count)))
      {
	List <Item> total_list;
	List_iterator <Item> field_list(select_lex->item_list);
	List_iterator <Item> value_list(lex->value_list);
	Item *item;
	while ((item=field_list++))
	  total_list.push_back(item);
	while ((item=value_list++))
	  total_list.push_back(item);

	res= mysql_select(thd, tables, total_list,
			  select_lex->where,
			  (ORDER *)NULL, (ORDER *)NULL, (Item *)NULL,
			  (ORDER *)NULL,
			  select_lex->options | thd->options |
			  SELECT_NO_JOIN_CACHE,
			  result, unit, select_lex, 0);
	delete result;
	if (thd->net.report_error)
	  res= -1;
      }
      else
	res= -1;					// Error is not sent
      close_thread_tables(thd);
    }
    break;
  case SQLCOM_REPLACE:
  case SQLCOM_INSERT:
  {
    ulong privilege= (lex->duplicates == DUP_REPLACE ?
                      INSERT_ACL | DELETE_ACL : INSERT_ACL);
    if (check_access(thd,privilege,tables->db,&tables->grant.privilege))
      goto error; /* purecov: inspected */
    if (grant_option && check_grant(thd,privilege,tables))
      goto error;
    res = mysql_insert(thd,tables,lex->field_list,lex->many_values,
		       lex->duplicates);
    if (thd->net.report_error)
      res= -1;
    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->duplicates == DUP_REPLACE ?
                        INSERT_ACL | DELETE_ACL : INSERT_ACL);
      TABLE_LIST *save_next=tables->next;
      tables->next=0;
      if (check_access(thd, privilege,
		       tables->db,&tables->grant.privilege) ||
	  (grant_option && check_grant(thd, privilege, tables)))
	goto error;
      tables->next=save_next;
      if ((res=check_table_access(thd, SELECT_ACL, save_next)))
	goto error;
    }

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

    if (find_real_table_in_list(tables->next, tables->db, tables->real_name))
    {
      net_printf(thd,ER_INSERT_TABLE_USED,tables->real_name);
      DBUG_VOID_RETURN;
    }

    /* 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);
      if (thd->net.report_error)
	res= -1;
    }
    else
      res= -1;
    break;
  }
  case SQLCOM_TRUNCATE:
    if (check_access(thd,DELETE_ACL,tables->db,&tables->grant.privilege))
      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,ER_LOCK_OR_ACTIVE_TRANSACTION,NullS);
      goto error;
    }
    res=mysql_truncate(thd,tables);
    break;
  case SQLCOM_DELETE:
  {
    if (check_access(thd,DELETE_ACL,tables->db,&tables->grant.privilege))
      goto error; /* purecov: inspected */
    if (grant_option && check_grant(thd,DELETE_ACL,tables))
      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);
    if (thd->net.report_error)
      res= -1;
    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,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,ER_NONUNIQ_TABLE,auxi->real_name);
	goto error;
      }
      walk->lock_type= auxi->lock_type;
      auxi->table_list=  walk;		// Remember corresponding table
    }
    if (add_item_to_list(new Item_null()))
    {
      res= -1;
      break;
    }
    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= auxi->table_list->table;
    if (&lex->select_lex != lex->all_selects_list)
      for (TABLE_LIST *t= select_lex->get_table_list();
	   t; t= t->next)
      {
	if (find_real_table_in_list(t->table_list->next, t->db, t->real_name))
	{
	  my_error(ER_INSERT_TABLE_USED, MYF(0), t->real_name);
	  res= -1;
	  break;
	}
      }
    fix_tables_pointers(lex->all_selects_list);
    if (!thd->fatal_error && (result= new multi_delete(thd,aux_tables,
						       table_count)))
    {
      res= mysql_select(thd,select_lex->get_table_list(),
			select_lex->item_list,
			select_lex->where,
			(ORDER *)NULL,(ORDER *)NULL,(Item *)NULL,
			(ORDER *)NULL,
			select_lex->options | thd->options |
			SELECT_NO_JOIN_CACHE,
			result, unit, select_lex, 0);
      if (thd->net.report_error)
	res= -1;
      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 (end_active_trans(thd))
      res= -1;
    else
      res = mysql_rm_table(thd,tables,lex->drop_if_exists);
  }
  break;
  case SQLCOM_DROP_INDEX:
    if (!tables->db)
      tables->db=thd->db;
    if (check_access(thd,INDEX_ACL,tables->db,&tables->grant.privilege))
      goto error;				/* purecov: inspected */
    if (grant_option && check_grant(thd,INDEX_ACL,tables))
      goto error;
    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,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_TABLE_TYPES:
    res= mysqld_show_table_types(thd);
    break;
  case SQLCOM_SHOW_PRIVILEGES:
    res= mysqld_show_privileges(thd);
    break;
  case SQLCOM_SHOW_COLUMN_TYPES:
    res= mysqld_show_column_types(thd);
    break;
  case SQLCOM_SHOW_STATUS:
    res= mysqld_show(thd,(lex->wild ? lex->wild->ptr() : NullS),status_vars,
		     OPT_GLOBAL);
    break;
  case SQLCOM_SHOW_VARIABLES:
    res= mysqld_show(thd, (lex->wild ? lex->wild->ptr() : NullS),
		     init_vars, lex->option_type);
    break;
  case SQLCOM_SHOW_LOGS:
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(thd,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      if (grant_option && check_access(thd, FILE_ACL, any_db))
	goto error;
      res= mysqld_show_logs(thd);
      break;
    }
#endif
  case SQLCOM_SHOW_TABLES:
    /* FALL THROUGH */
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(thd,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,ER_NO_DB_ERROR);	/* purecov: inspected */
	goto error;				/* purecov: inspected */
      }
      remove_escape(db);				// Fix escaped '_'
      if (check_db_name(db))
      {
        net_printf(thd,ER_WRONG_DB_NAME, db);
        goto error;
      }
      if (check_access(thd,SELECT_ACL,db,&thd->col_access))
	goto error;				/* purecov: inspected */
      /* 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_CHARSETS:
    res= mysqld_show_charsets(thd,(lex->wild ? lex->wild->ptr() : NullS));
    break;
  case SQLCOM_SHOW_FIELDS:
#ifdef DONT_ALLOW_SHOW_COMMANDS
    send_error(thd,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      char *db=tables->db;
      if (!*db)
      {
	send_error(thd,ER_NO_DB_ERROR);	/* purecov: inspected */
	goto error;				/* purecov: inspected */
      }
      remove_escape(db);			// Fix escaped '_'
      remove_escape(tables->real_name);
      if (check_access(thd,SELECT_ACL | EXTRA_ACL,db,&thd->col_access))
	goto error;				/* purecov: inspected */
      tables->grant.privilege=thd->col_access;
      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,ER_NOT_ALLOWED_COMMAND);	/* purecov: inspected */
    DBUG_VOID_RETURN;
#else
    {
      char *db=tables->db;
      if (!db)
      {
	send_error(thd,ER_NO_DB_ERROR);	/* purecov: inspected */
	goto error;				/* purecov: inspected */
      }
      remove_escape(db);			// Fix escaped '_'
      remove_escape(tables->real_name);
      if (!tables->db)
	tables->db=thd->db;
      if (check_access(thd,SELECT_ACL,db,&thd->col_access))
	goto error; /* purecov: inspected */
      tables->grant.privilege=thd->col_access;
      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,ER_NOT_ALLOWED_COMMAND);
	goto error;
      }
      if (check_access(thd,privilege,tables->db,&tables->grant.privilege) ||
	  grant_option && check_grant(thd,privilege,tables))
	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);
    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);
    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)))
    {
      thd->locked_tables=thd->lock;
      thd->lock=0;
      send_ok(thd);
    }
    else
      thd->options&= ~(ulong) (OPTION_TABLE_LOCK);
    thd->in_lock_tables=0;
    break;
  case SQLCOM_CREATE_DB:
  {
    if (!strip_sp(lex->name) || check_db_name(lex->name))
    {
      net_printf(thd,ER_WRONG_DB_NAME, lex->name);
      break;
    }
    if (lower_case_table_names)
      my_casedn_str(system_charset_info, lex->name);
    if (check_access(thd,CREATE_ACL,lex->name,0,1))
      break;
    res=mysql_create_db(thd,lex->name,&lex->create_info,0);
    break;
  }
  case SQLCOM_DROP_DB:
  {
    if (!strip_sp(lex->name) || check_db_name(lex->name))
    {
      net_printf(thd,ER_WRONG_DB_NAME, lex->name);
      break;
    }
    if (lower_case_table_names)
      my_casedn_str(system_charset_info, lex->name);
    if (check_access(thd,DROP_ACL,lex->name,0,1))
      break;
    if (thd->locked_tables || thd->active_transaction())
    {
      send_error(thd,ER_LOCK_OR_ACTIVE_TRANSACTION);
      goto error;
    }
    res=mysql_rm_db(thd,lex->name,lex->drop_if_exists,0);
    break;
  }
  case SQLCOM_ALTER_DB:
  {
    if (!strip_sp(lex->name) || check_db_name(lex->name))
    {
      net_printf(thd,ER_WRONG_DB_NAME, lex->name);
      break;
    }
    if (check_access(thd,ALTER_ACL,lex->name,0,1))
      break;
    if (thd->locked_tables || thd->active_transaction())
    {
      send_error(thd,ER_LOCK_OR_ACTIVE_TRANSACTION);
      goto error;
    }
    res=mysql_alter_db(thd,lex->name,&lex->create_info);
    break;
  }
  case SQLCOM_SHOW_CREATE_DB:
  {
    if (!strip_sp(lex->name) || check_db_name(lex->name))
    {
      net_printf(thd,ER_WRONG_DB_NAME, lex->name);
      break;
    }
    if (check_access(thd,DROP_ACL,lex->name,0,1))
      break;
    if (thd->locked_tables || thd->active_transaction())
    {
      send_error(thd,ER_LOCK_OR_ACTIVE_TRANSACTION);
      goto error;
    }
    res=mysqld_show_create_db(thd,lex->name,&lex->create_info);
    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);
#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);
#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(system_charset_info,
                           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())
	{
	  Query_log_event qinfo(thd, thd->query, thd->query_length, 0);
	  mysql_bin_log.write(&qinfo);
	}
      }
    }
    else
    {
      if (lex->columns.elements)
      {
	send_error(thd,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())
	{
	  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;
    if (reload_acl_and_cache(thd, lex->type, tables))
      send_error(thd,0);
    else
      send_ok(thd);
    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:
    if (check_db_used(thd,tables) ||
	check_table_access(thd,SELECT_ACL, 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);
    }
    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);
    }
    else
      res= -1;
    break;
  }
  case SQLCOM_ROLLBACK:
    thd->server_status&= ~SERVER_STATUS_IN_TRANS;
    if (!ha_rollback(thd))
    {
      if (thd->options & OPTION_STATUS_NO_TRANS_UPDATE)
	send_warning(thd,ER_WARNING_NOT_COMPLETE_ROLLBACK,0);
      else
	send_ok(thd);
    }
    else
      res= -1;
    thd->options&= ~(ulong) (OPTION_BEGIN | OPTION_STATUS_NO_TRANS_UPDATE);
    break;
  default:					/* Impossible */
    send_ok(thd);
    break;
  }
  thd->proc_info="query end";			// QQ
  if (res < 0)
    send_error(thd,thd->killed ? ER_SERVER_SHUTDOWN : 0);

error:
  DBUG_VOID_RETURN;
}


/****************************************************************************
  Get the user (global) and database privileges for all used tables
  Returns true (error) if we can't get the privileges and we don't use
  table/column grants.
  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.
****************************************************************************/

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,ER_NO_DB_ERROR);	/* purecov: tested */
    DBUG_RETURN(TRUE);				/* purecov: tested */
  }

  if ((thd->master_access & want_access) == want_access)
  {
    *save_priv=thd->master_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,ER_ACCESS_DENIED_ERROR,
		 thd->priv_user,
		 thd->host_or_ip,
		 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); /* 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 & ~TABLE_ACLS)))
    DBUG_RETURN(FALSE);				/* Ok */
  if (!no_errors)
    net_printf(thd,ER_DBACCESS_DENIED_ERROR,
	       thd->priv_user,
	       thd->host_or_ip,
	       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 */

bool check_global_access(THD *thd, ulong want_access)
{
  char command[128];
  if ((thd->master_access & want_access) == want_access)
    return 0;
  get_privilege_desc(command, sizeof(command), want_access);
  net_printf(thd,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 (tables->derived || (tables->table && (int)tables->table->tmp_table))
      continue;
    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_db_used(THD *thd,TABLE_LIST *tables)
{
  for (; tables ; tables=tables->next)
  {
    if (!tables->db)
    {
      if (!(tables->db=thd->db))
      {
	send_error(thd,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,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

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;
}

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

bool my_yyoverflow(short **yyss, YYSTYPE **yyvs, int *yystacksize)
{
  LEX	*lex=current_lex;
  int  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
****************************************************************************/

void
mysql_init_query(THD *thd)
{
  DBUG_ENTER("mysql_init_query");
  LEX *lex=&thd->lex;
  lex->unit.init_query();
  lex->unit.init_select();
  lex->select_lex.init_query();
  lex->value_list.empty();
  lex->param_list.empty();
  lex->unit.global_parameters= lex->unit.slave= lex->current_select=
    lex->all_selects_list= &lex->select_lex;
  lex->select_lex.master= &lex->unit;
  lex->select_lex.prev= &lex->unit.slave;
  lex->select_lex.link_next= 0;
  lex->select_lex.link_prev= (st_select_lex_node**)&(lex->all_selects_list);
  lex->olap=lex->describe=0;
  lex->derived_tables= false;
  thd->check_loops_counter= thd->select_number=
    lex->select_lex.select_number= 1;
  thd->free_list= 0;
  thd->total_warn_count=0;			// Warnings for this query
  thd->last_insert_id_used= thd->query_start_used= thd->insert_id_used=0;
  thd->sent_row_count= thd->examined_row_count= 0;
  thd->fatal_error= thd->rand_used= 0;
  thd->possible_loops= 0;
  DBUG_VOID_RETURN;
}

void
mysql_init_select(LEX *lex)
{
  SELECT_LEX *select_lex= lex->current_select->select_lex();
  DBUG_ASSERT(select_lex->linkage != GLOBAL_OPTIONS_TYPE);
  select_lex->init_select();
  select_lex->master_unit()->select_limit= select_lex->select_limit=
    lex->thd->variables.select_limit;
  lex->exchange= 0;
  lex->result= 0;
  lex->proc_list.first= 0;
}


bool
mysql_new_select(LEX *lex, bool move_down)
{
  SELECT_LEX *select_lex = new SELECT_LEX();
  select_lex->select_number= ++lex->thd->select_number;
  if (!select_lex)
    return 1;
  select_lex->init_query();
  select_lex->init_select();
  if (move_down)
  {
    /* first select_lex of subselect or derived table */
    SELECT_LEX_UNIT *unit= new SELECT_LEX_UNIT();
    if (!unit)
      return 1;
    unit->init_query();
    unit->init_select();
    unit->include_down(lex->current_select);
    select_lex->include_down(unit);
  }
  else
    select_lex->include_neighbour(lex->current_select);

  select_lex->master_unit()->global_parameters= select_lex;
  DBUG_ASSERT(lex->current_select->linkage != GLOBAL_OPTIONS_TYPE);
  select_lex->include_global((st_select_lex_node**)&lex->all_selects_list);
  lex->current_select= select_lex;
  return 0;
}

/*
  Create a select to return the same output as 'SELECT @@var_name'.

  SYNOPSIS
    create_select_for_variable()
    var_name		Variable name

  DESCRIPTION
    Used for SHOW COUNT(*) [ WARNINGS | ERROR]

    This will crash with a core dump if the variable doesn't exists
*/

void create_select_for_variable(const char *var_name)
{
  LEX *lex;
  LEX_STRING tmp;
  DBUG_ENTER("create_select_for_variable");
  lex= current_lex;
  mysql_init_select(lex);
  lex->sql_command= SQLCOM_SELECT;
  tmp.str= (char*) var_name;
  tmp.length=strlen(var_name);
  add_item_to_list(get_system_var(OPT_SESSION, tmp));
  DBUG_VOID_RETURN;
}


void mysql_init_multi_delete(LEX *lex)
{
  lex->sql_command=  SQLCOM_DELETE_MULTI;
  mysql_init_select(lex);
  lex->select_lex.select_limit= lex->unit.select_limit_cnt=
    HA_POS_ERROR;
  lex->auxilliary_table_list= lex->select_lex.table_list;
  lex->select_lex.init_query();
}


void
mysql_parse(THD *thd, char *inBuf, uint length)
{
  DBUG_ENTER("mysql_parse");

  mysql_init_query(thd);
  thd->query_length = length;
  thd->net.report_error= 0;

  if (query_cache_send_result_to_client(thd, inBuf, length) <= 0)
  {
    LEX *lex=lex_start(thd, (uchar*) inBuf, length);
    if (!yyparse((void *)thd) && ! thd->fatal_error)
    {
      if (mqh_used && thd->user_connect &&
	  check_mqh(thd, lex->sql_command))
      {
	thd->net.error = 0;
      }
      else
      {
	if (thd->net.report_error)
	  send_error(thd, 0, NullS);
	else
	{
	  mysql_execute_command(thd);
	  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_list);  /* Free strings used by items */
    lex_end(lex);
  }
  DBUG_VOID_RETURN;
}


inline static void
link_in_list(SQL_LIST *list,byte *element,byte **next)
{
  list->elements++;
  (*list->next)=element;
  list->next=next;
  *next=0;
}


/*****************************************************************************
** 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, Item *comment,
		       char *change, TYPELIB *interval, CHARSET_INFO *cs)
{
  register create_field *new_field;
  THD	*thd=current_thd;
  LEX  *lex= &thd->lex;
  uint allowed_type_modifier=0;
  char warn_buff[MYSQL_ERRMSG_SIZE];
  DBUG_ENTER("add_field_to_list");

  if (strlen(field_name) > NAME_LEN)
  {
    net_printf(thd, 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, HA_KEY_ALG_UNDEF,
				    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, HA_KEY_ALG_UNDEF,
				    lex->col_list));
    lex->col_list.empty();
  }

  if (default_value && default_value->type() == Item::NULL_ITEM)
  {
    if ((type_modifier & (NOT_NULL_FLAG | AUTO_INCREMENT_FLAG)) ==
	NOT_NULL_FLAG)
    {
      net_printf(thd,ER_INVALID_DEFAULT,field_name);
      DBUG_RETURN(1);
    }
    default_value=0;
  }
  if (!(new_field=new create_field()))
    DBUG_RETURN(1);
  new_field->field=0;
  new_field->field_name=field_name;
  new_field->def= (type_modifier & AUTO_INCREMENT_FLAG ? 0 : default_value);
  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;
  new_field->charset=cs;

  if (!comment)
  {
    new_field->comment.str=0;
    new_field->comment.length=0;
  }
  else
  {
    /* In this case comment is always of type Item_string */
    new_field->comment.str=   (char*) comment->str_value.ptr();
    new_field->comment.length=comment->str_value.length();
  }
  if (length)
    if (!(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_NULL:
  case FIELD_TYPE_GEOMETRY:
    break;
  case FIELD_TYPE_DECIMAL:
    if (!length)
      new_field->length = 10;			// Default length for DECIMAL
    new_field->length+=sign_len;
    if (new_field->decimals)
      new_field->length++;
    break;
  case FIELD_TYPE_STRING:
  case FIELD_TYPE_VAR_STRING:
    if (new_field->length < MAX_FIELD_WIDTH || default_value)
      break;
    /* Convert long CHAR() and VARCHAR columns to TEXT or BLOB */
    new_field->sql_type= FIELD_TYPE_BLOB;
    sprintf(warn_buff, ER(ER_AUTO_CONVERT), field_name, "CHAR",
	    (cs == my_charset_bin) ? "BLOB" : "TEXT");
    push_warning(thd, MYSQL_ERROR::WARN_LEVEL_WARN, ER_AUTO_CONVERT,
		 warn_buff);
    /* fall through */
  case FIELD_TYPE_BLOB:
  case FIELD_TYPE_TINY_BLOB:
  case FIELD_TYPE_LONG_BLOB:
  case FIELD_TYPE_MEDIUM_BLOB:
    if (new_field->length)
    {
      /* The user has given a length to the blob column */
      if (new_field->length < 256)
	type= FIELD_TYPE_TINY_BLOB;
      if (new_field->length < 65536)
	type= FIELD_TYPE_BLOB;
      else if (new_field->length < 256L*256L*256L)
	type= FIELD_TYPE_MEDIUM_BLOB;
      else
	type= FIELD_TYPE_LONG_BLOB;
      new_field->length= 0;
    }
    new_field->sql_type= type;
    if (default_value)				// Allow empty as default value
    {
      String str,*res;
      res=default_value->val_str(&str);
      if (res->length())
      {
	net_printf(thd,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,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
    {
      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,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,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,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,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,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(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;
  link_in_list(&current_lex->proc_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(system_charset_info) &&
        (l = my_ismbchar(system_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;
  link_in_list(&list,(byte*) order,(byte**) &order->next);
  DBUG_RETURN(0);
}


TABLE_LIST *st_select_lex::add_table_to_list(Table_ident *table,
					     LEX_STRING *alias,
					     bool updating,
					     thr_lock_type flags,
					     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 (table->table.length > NAME_LEN ||
      (table->table.length &&
       check_table_name(table->table.str,table->table.length)) ||
      table->db.str && check_db_name(table->db.str))
  {
    net_printf(thd,ER_WRONG_TABLE_NAME,table->table.str);
    DBUG_RETURN(0);
  }

  if (!alias)					/* Alias is case sensitive */
  {
    if (table->sel)
    {
      net_printf(thd,ER_DERIVED_MUST_HAVE_ALIAS);
      DBUG_RETURN(0);
    }
    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
  {
    /* The following can't be "" as we may do 'casedn_str()' on it */
    ptr->db= empty_c_string;
    ptr->db_length= 0;
  }

  ptr->alias= alias_str;
  if (lower_case_table_names)
  {
    my_casedn_str(system_charset_info,ptr->db);
    my_casedn_str(system_charset_info,table->table.str);
  }
  ptr->real_name=table->table.str;
  ptr->real_name_length=table->table.length;
  ptr->lock_type=flags;
  ptr->updating=updating;
  ptr->derived= (SELECT_LEX_UNIT *) table->sel;
  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 (flags != TL_IGNORE)
  {
    for (TABLE_LIST *tables=(TABLE_LIST*) table_list.first ;
	 tables ;
	 tables=tables->next)
    {
      if (!strcmp(alias_str,tables->alias) && !strcmp(ptr->db, tables->db))
      {
	net_printf(thd,ER_NONUNIQ_TABLE,alias_str); /* purecov: tested */
	DBUG_RETURN(0);				/* purecov: tested */
      }
    }
  }
  link_in_list(&table_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 st_select_lex::set_lock_for_tables(thr_lock_type lock_type)
{
  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*) table_list.first ;
       tables ;
       tables=tables->next)
  {
    tables->lock_type= lock_type;
    tables->updating=  for_update;
  }
  DBUG_VOID_RETURN;
}


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();
  }
}


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

bool reload_acl_and_cache(THD *thd, ulong options, TABLE_LIST *tables)
{
  bool result=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)
  {
    mysql_log.new_file(1);
    mysql_update_log.new_file(1);
    mysql_bin_log.new_file(1);
    mysql_slow_log.new_file(1);
    if (ha_flush_logs())
      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)
 {
   LOCK_ACTIVE_MI;
   if (reset_slave(thd, active_mi))
     result=1;
   UNLOCK_ACTIVE_MI;
 }
 if (options & REFRESH_USER_RESOURCES)
   reset_mqh(thd,(LEX_USER *) NULL);
 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);
  else
    net_printf(thd,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, char **filename_ptr, 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.current_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, ER_CANT_USE_OPTION_HERE, command);
    return 1;
  }
  return 0;
}

compare_func_creator comp_eq_creator(bool invert)
{
  return invert?&Item_bool_func2::ne_creator:&Item_bool_func2::eq_creator;
}

compare_func_creator comp_ge_creator(bool invert)
{
  return invert?&Item_bool_func2::lt_creator:&Item_bool_func2::ge_creator;
}

compare_func_creator comp_gt_creator(bool invert)
{
  return invert?&Item_bool_func2::le_creator:&Item_bool_func2::gt_creator;
}

compare_func_creator comp_le_creator(bool invert)
{
  return invert?&Item_bool_func2::gt_creator:&Item_bool_func2::le_creator;
}

compare_func_creator comp_lt_creator(bool invert)
{
  return invert?&Item_bool_func2::ge_creator:&Item_bool_func2::lt_creator;
}

compare_func_creator comp_ne_creator(bool invert)
{
  return invert?&Item_bool_func2::eq_creator:&Item_bool_func2::ne_creator;
}