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/* Copyright (C) 1995-2002 MySQL AB
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/**********************************************************************
This file contains the implementation of prepare and executes.
Prepare:
- Server gets the query from client with command 'COM_PREPARE';
in the following format:
[COM_PREPARE:1] [query]
- Parse the query and recognize any parameter markers '?' and
store its information list in lex->param_list
- Allocate a new statement for this prepare; and keep this in
'thd->prepared_statements' pool.
- Without executing the query, return back to client the total
number of parameters along with result-set metadata information
(if any) in the following format:
[STMT_ID:4][Columns:2][Param_count:2][Columns meta info][Params meta info]
Prepare-execute:
- Server gets the command 'COM_EXECUTE' to execute the
previously prepared query. If there is any param markers; then client
will send the data in the following format:
[COM_EXECUTE:1]
[STMT_ID:4]
[NULL_BITS:(param_count+7)/8)]
[TYPES_SUPPLIED_BY_CLIENT(0/1):1]
[[length]data]
[[length]data] .. [[length]data].
(Note: Except for string/binary types; all other types will not be
supplied with length field)
- Replace the param items with this new data. If it is a first execute
or types altered by client; then setup the conversion routines.
- Execute the query without re-parsing and send back the results
to client
Long data handling:
- Server gets the long data in pieces with command type 'COM_LONG_DATA'.
- The packet recieved will have the format as:
[COM_LONG_DATA:1][STMT_ID:4][parameter_number:2][type:2][data]
- Checks if the type is specified by client, and if yes reads the type,
and stores the data in that format.
- It's up to the client to check for read data ended. The server doesn't
care; and also server doesn't notify to the client that it got the
data or not; if there is any error; then during execute; the error
will be returned
***********************************************************************/
#include "mysql_priv.h"
#include "sql_acl.h"
#include <assert.h> // for DEBUG_ASSERT()
#include <m_ctype.h> // for isspace()
#define IS_PARAM_NULL(pos, param_no) pos[param_no/8] & (1 << param_no & 7)
extern int yyparse(void *thd);
/*
Find prepared statement in thd
SYNOPSIS
find_prepared_statement()
thd Thread handler
stmt_id Statement id server specified to the client on prepare
RETURN VALUES
0 error. In this case the error is sent with my_error()
ptr Pointer to statement
*/
static PREP_STMT *find_prepared_statement(THD *thd, ulong stmt_id,
const char *when)
{
PREP_STMT *stmt;
DBUG_ENTER("find_prepared_statement");
DBUG_PRINT("enter",("stmt_id: %d", stmt_id));
if (thd->last_prepared_stmt && thd->last_prepared_stmt->stmt_id == stmt_id)
DBUG_RETURN(thd->last_prepared_stmt);
if ((stmt= (PREP_STMT*) tree_search(&thd->prepared_statements, &stmt_id,
(void*) 0)))
DBUG_RETURN (thd->last_prepared_stmt= stmt);
my_error(ER_UNKNOWN_STMT_HANDLER, MYF(0), stmt_id, when);
DBUG_RETURN(0);
}
/*
Compare two prepared statements; Used to find a prepared statement
*/
int compare_prep_stmt(void *not_used, PREP_STMT *stmt, ulong *key)
{
return (stmt->stmt_id == *key) ? 0 : (stmt->stmt_id < *key) ? -1 : 1;
}
/*
Free prepared statement.
SYNOPSIS
standard tree_element_free function.
DESCRIPTION
We don't have to free the stmt itself as this was stored in the tree
and will be freed when the node is deleted
*/
void free_prep_stmt(PREP_STMT *stmt, TREE_FREE mode, void *not_used)
{
free_items(stmt->free_list);
free_root(&stmt->mem_root, MYF(0));
}
/*
Send prepared stmt info to client after prepare
*/
static bool send_prep_stmt(PREP_STMT *stmt, uint columns)
{
NET *net=&stmt->thd->net;
char buff[8];
int4store(buff, stmt->stmt_id);
int2store(buff+4, columns);
int2store(buff+6, stmt->param_count);
return (my_net_write(net, buff, sizeof(buff)) || net_flush(net));
}
/*
Send information about all item parameters
TODO: Not yet ready
*/
static bool send_item_params(PREP_STMT *stmt)
{
#if 0
char buff[1];
buff[0]=0;
if (my_net_write(&stmt->thd->net, buff, sizeof(buff)))
return 1;
send_eof(stmt->thd);
#endif
return 0;
}
/*
Read the length of the parameter data and retun back to
caller by positing the pointer to param data
*/
static ulong get_param_length(uchar **packet)
{
reg1 uchar *pos= *packet;
if (*pos < 251)
{
(*packet)++;
return (ulong) *pos;
}
if (*pos == 252)
{
(*packet)+=3;
return (ulong) uint2korr(pos+1);
}
if (*pos == 253)
{
(*packet)+=4;
return (ulong) uint3korr(pos+1);
}
(*packet)+=9; // Must be 254 when here
return (ulong) uint4korr(pos+1);
}
/*
Setup param conversion routines
setup_param_xx()
param Parameter Item
pos Input data buffer
All these functions reads the data from pos and sets up that data
through 'param' and advances the buffer position to predifined
length position.
Make a note that the NULL handling is examined at first execution
(i.e. when input types altered) and for all subsequent executions
we don't read any values for this.
RETURN VALUES
*/
static void setup_param_tiny(Item_param *param, uchar **pos)
{
param->set_int((longlong)(**pos));
*pos+= 1;
}
static void setup_param_short(Item_param *param, uchar **pos)
{
param->set_int((longlong)sint2korr(*pos));
*pos+= 2;
}
static void setup_param_int32(Item_param *param, uchar **pos)
{
param->set_int((longlong)sint4korr(*pos));
*pos+= 4;
}
static void setup_param_int64(Item_param *param, uchar **pos)
{
param->set_int((longlong)sint8korr(*pos));
*pos+= 8;
}
static void setup_param_float(Item_param *param, uchar **pos)
{
float data;
float4get(data,*pos);
param->set_double((double) data);
*pos+= 4;
}
static void setup_param_double(Item_param *param, uchar **pos)
{
double data;
float8get(data,*pos);
param->set_double((double) data);
*pos+= 8;
}
static void setup_param_str(Item_param *param, uchar **pos)
{
ulong len=get_param_length(pos);
param->set_value((const char *)*pos, len);
*pos+=len;
}
static void setup_param_functions(Item_param *param, uchar param_type)
{
switch (param_type) {
case FIELD_TYPE_TINY:
param->setup_param_func= setup_param_tiny;
param->item_result_type = INT_RESULT;
break;
case FIELD_TYPE_SHORT:
param->setup_param_func= setup_param_short;
param->item_result_type = INT_RESULT;
break;
case FIELD_TYPE_LONG:
param->setup_param_func= setup_param_int32;
param->item_result_type = INT_RESULT;
break;
case FIELD_TYPE_LONGLONG:
param->setup_param_func= setup_param_int64;
param->item_result_type = INT_RESULT;
break;
case FIELD_TYPE_FLOAT:
param->setup_param_func= setup_param_float;
param->item_result_type = REAL_RESULT;
break;
case FIELD_TYPE_DOUBLE:
param->setup_param_func= setup_param_double;
param->item_result_type = REAL_RESULT;
break;
default:
param->setup_param_func= setup_param_str;
param->item_result_type = STRING_RESULT;
}
}
/*
Update the parameter markers by reading the data
from client ..
*/
static bool setup_params_data(PREP_STMT *stmt)
{
THD *thd= stmt->thd;
List<Item> &params= thd->lex.param_list;
List_iterator<Item> param_iterator(params);
Item_param *param;
DBUG_ENTER("setup_params_data");
uchar *pos=(uchar*) thd->net.read_pos+1+MYSQL_STMT_HEADER; //skip header
uchar *read_pos= pos+(stmt->param_count+7) / 8; //skip null bits
if (*read_pos++) //types supplied / first execute
{
/*
First execute or types altered by the client, setup the
conversion routines for all parameters (one time)
*/
while ((param= (Item_param *)param_iterator++))
{
setup_param_functions(param,*read_pos);
read_pos+= 2;
}
param_iterator.rewind();
}
ulong param_no= 0;
while ((param= (Item_param *)param_iterator++))
{
if (!param->long_data_supplied)
{
if (IS_PARAM_NULL(pos,param_no))
param->maybe_null= param->null_value= 1;
else
{
param->maybe_null= param->null_value= 0;
param->setup_param_func(param,&read_pos);
}
}
param_no++;
}
DBUG_RETURN(0);
}
/*
Validates insert fields
*/
static int check_prepare_fields(THD *thd,TABLE *table, List<Item> &fields,
List<Item> &values, ulong counter)
{
if (fields.elements == 0 && values.elements != 0)
{
if (values.elements != table->fields)
{
my_printf_error(ER_WRONG_VALUE_COUNT_ON_ROW,
ER(ER_WRONG_VALUE_COUNT_ON_ROW),
MYF(0),counter);
return -1;
}
}
else
{
if (fields.elements != values.elements)
{
my_printf_error(ER_WRONG_VALUE_COUNT_ON_ROW,
ER(ER_WRONG_VALUE_COUNT_ON_ROW),
MYF(0),counter);
return -1;
}
TABLE_LIST table_list;
bzero((char*) &table_list,sizeof(table_list));
table_list.db= table->table_cache_key;
table_list.real_name= table_list.alias= table->table_name;
table_list.table= table;
table_list.grant= table->grant;
thd->dupp_field=0;
if (setup_tables(&table_list) ||
setup_fields(thd,&table_list,fields,1,0,0))
return -1;
if (thd->dupp_field)
{
my_error(ER_FIELD_SPECIFIED_TWICE,MYF(0), thd->dupp_field->field_name);
return -1;
}
}
return 0;
}
/*
Validate the following information for INSERT statement:
- field existance
- fields count
*/
static bool mysql_test_insert_fields(PREP_STMT *stmt,
TABLE_LIST *table_list,
List<Item> &fields,
List<List_item> &values_list)
{
THD *thd= stmt->thd;
TABLE *table;
List_iterator_fast<List_item> its(values_list);
List_item *values;
DBUG_ENTER("mysql_test_insert_fields");
if (!(table = open_ltable(thd,table_list,table_list->lock_type)))
DBUG_RETURN(1);
if ((values= its++))
{
uint value_count;
ulong counter= 0;
if (check_insert_fields(thd,table,fields,*values,1))
DBUG_RETURN(1);
value_count= values->elements;
its.rewind();
while ((values= its++))
{
counter++;
if (values->elements != value_count)
{
my_printf_error(ER_WRONG_VALUE_COUNT_ON_ROW,
ER(ER_WRONG_VALUE_COUNT_ON_ROW),
MYF(0), counter);
DBUG_RETURN(1);
}
}
}
if (send_prep_stmt(stmt, 0) || send_item_params(stmt))
DBUG_RETURN(1);
DBUG_RETURN(0);
}
/*
Validate the following information
UPDATE - set and where clause DELETE - where clause
And send update-set clause column list fields info
back to client. For DELETE, just validate where clause
and return no fields information back to client.
*/
static bool mysql_test_upd_fields(PREP_STMT *stmt, TABLE_LIST *table_list,
List<Item> &fields, List<Item> &values,
COND *conds)
{
THD *thd= stmt->thd;
DBUG_ENTER("mysql_test_upd_fields");
if (open_and_lock_tables(thd, table_list))
DBUG_RETURN(1);
if (setup_tables(table_list) || setup_fields(thd,table_list,fields,1,0,0) ||
setup_conds(thd,table_list,&conds))
DBUG_RETURN(1);
/*
Currently return only column list info only, and we are not
sending any info on where clause.
*/
if (send_prep_stmt(stmt, 0) || send_item_params(stmt))
DBUG_RETURN(1);
DBUG_RETURN(0);
}
/*
Validate the following information:
SELECT - column list
- where clause
- order clause
- having clause
- group by clause
- if no column spec i.e. '*', then setup all fields
And send column list fields info back to client.
*/
static bool mysql_test_select_fields(PREP_STMT *stmt, TABLE_LIST *tables,
List<Item> &fields, List<Item> &values,
COND *conds, ORDER *order, ORDER *group,
Item *having)
{
bool hidden_group_fields;
THD *thd= stmt->thd;
List<Item> all_fields(fields);
DBUG_ENTER("mysql_test_select_fields");
if (open_and_lock_tables(thd, tables))
DBUG_RETURN(1);
thd->used_tables=0; // Updated by setup_fields
if (setup_tables(tables) ||
setup_fields(thd,tables,fields,1,&all_fields,1) ||
setup_conds(thd,tables,&conds) ||
setup_order(thd,tables,fields,all_fields,order) ||
setup_group(thd,tables,fields,all_fields,group,&hidden_group_fields))
DBUG_RETURN(1);
if (having)
{
thd->where="having clause";
thd->allow_sum_func=1;
if (having->check_cols(1) || having->fix_fields(thd, tables, &having)
|| thd->fatal_error)
DBUG_RETURN(1);
if (having->with_sum_func)
having->split_sum_func(all_fields);
}
if (setup_ftfuncs(&thd->lex.select_lex))
DBUG_RETURN(1);
/*
Currently return only column list info only, and we are not
sending any info on where clause.
*/
if (send_prep_stmt(stmt, fields.elements) ||
thd->protocol_simple.send_fields(&fields,0) ||
send_item_params(stmt))
DBUG_RETURN(1);
DBUG_RETURN(0);
}
/*
Check the access privileges
*/
static bool check_prepare_access(THD *thd, TABLE_LIST *tables,
uint type)
{
if (check_access(thd,type,tables->db,&tables->grant.privilege))
return 1;
if (grant_option && check_grant(thd,type,tables))
return 1;
return 0;
}
/*
Send the prepare query results back to client
*/
static bool send_prepare_results(PREP_STMT *stmt)
{
THD *thd= stmt->thd;
LEX *lex= &thd->lex;
enum enum_sql_command sql_command = thd->lex.sql_command;
DBUG_ENTER("send_prepare_results");
DBUG_PRINT("enter",("command: %d, param_count: %ld",
sql_command, lex->param_count));
/* Setup prepared stmt */
stmt->param_count= lex->param_count;
stmt->free_list= thd->free_list; // Save items used in stmt
thd->free_list= 0;
SELECT_LEX *select_lex = &lex->select_lex;
TABLE_LIST *tables=(TABLE_LIST*) select_lex->table_list.first;
switch (sql_command) {
case SQLCOM_INSERT:
if (mysql_test_insert_fields(stmt, tables, lex->field_list,
lex->many_values))
goto abort;
break;
case SQLCOM_UPDATE:
if (mysql_test_upd_fields(stmt, tables, select_lex->item_list,
lex->value_list, select_lex->where))
goto abort;
break;
case SQLCOM_DELETE:
if (mysql_test_upd_fields(stmt, tables, select_lex->item_list,
lex->value_list, select_lex->where))
goto abort;
break;
case SQLCOM_SELECT:
if (mysql_test_select_fields(stmt, tables, select_lex->item_list,
lex->value_list, select_lex->where,
(ORDER*) select_lex->order_list.first,
(ORDER*) select_lex->group_list.first, select_lex->having))
goto abort;
break;
default:
{
/*
Rest fall through to default category, no parsing
for non-DML statements
*/
if (send_prep_stmt(stmt, 0))
goto abort;
}
}
DBUG_RETURN(0);
abort:
send_error(thd,thd->killed ? ER_SERVER_SHUTDOWN : 0);
DBUG_RETURN(1);
}
/*
Parse the prepare query
*/
static bool parse_prepare_query(PREP_STMT *stmt,
char *packet, uint length)
{
bool error= 1;
THD *thd= stmt->thd;
DBUG_ENTER("parse_prepare_query");
mysql_log.write(thd,COM_PREPARE,"%s",packet);
mysql_init_query(thd);
thd->prepare_command=true;
thd->lex.param_count= 0;
LEX *lex=lex_start(thd, (uchar*) packet, length);
lex->safe_to_cache_query= 0;
if (!yyparse((void *)thd) && !thd->fatal_error)
error= send_prepare_results(stmt);
lex_end(lex);
DBUG_RETURN(error);
}
/*
Initialize parameter items in statement
*/
static bool init_param_items(PREP_STMT *stmt)
{
List<Item> &params= stmt->thd->lex.param_list;
Item_param **to;
if (!(stmt->param= to= (Item_param **)
my_malloc(sizeof(Item_param *)*(stmt->param_count+1),
MYF(MY_WME))))
return 1;
List_iterator<Item> param_iterator(params);
while ((*(to++) = (Item_param *)param_iterator++));
return 0;
}
/*
Initialize stmt execution
*/
static void init_stmt_execute(PREP_STMT *stmt)
{
THD *thd= stmt->thd;
TABLE_LIST *tables=(TABLE_LIST*) thd->lex.select_lex.table_list.first;
/*
TODO: When the new table structure is ready, then have a status bit
to indicate the table is altered, and re-do the setup_*
and open the tables back.
*/
if (tables)
tables->table=0; //safety - nasty init
}
/*
Parse the query and send the total number of parameters
and resultset metadata information back to client (if any),
without executing the query i.e. with out any log/disk
writes. This will allow the queries to be re-executed
without re-parsing during execute.
If parameter markers are found in the query, then store
the information using Item_param along with maintaining a
list in lex->param_list, so that a fast and direct
retrieveal can be made without going through all field
items.
*/
bool mysql_stmt_prepare(THD *thd, char *packet, uint packet_length)
{
MEM_ROOT thd_root = thd->mem_root;
PREP_STMT stmt;
DBUG_ENTER("mysql_stmt_prepare");
bzero((char*) &stmt, sizeof(stmt));
stmt.stmt_id= ++thd->current_stmt_id;
init_sql_alloc(&stmt.mem_root, 8192, 8192);
stmt.thd= thd;
stmt.thd->mem_root= stmt.mem_root;
if (alloc_query(stmt.thd, packet, packet_length))
goto err;
if (parse_prepare_query(&stmt, thd->query, thd->query_length))
goto err;
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),WAIT_PRIOR);
if (init_param_items(&stmt))
goto err;
stmt.mem_root= stmt.thd->mem_root;
tree_insert(&thd->prepared_statements, (void *)&stmt, 0, (void *)0);
thd->mem_root= thd_root; // restore main mem_root
DBUG_RETURN(0);
err:
stmt.mem_root= stmt.thd->mem_root;
free_prep_stmt(&stmt, free_free, (void*) 0);
thd->mem_root = thd_root; // restore main mem_root
DBUG_RETURN(1);
}
/*
Executes previously prepared query
If there is any parameters(thd->param_count), then replace
markers with the data supplied from client, and then
execute the query
*/
void mysql_stmt_execute(THD *thd, char *packet)
{
ulong stmt_id= uint4korr(packet);
PREP_STMT *stmt;
DBUG_ENTER("mysql_stmt_execute");
if (!(stmt=find_prepared_statement(thd, stmt_id, "execute")))
{
send_error(thd);
DBUG_VOID_RETURN;
}
/* Check if we got an error when sending long data */
if (stmt->error_in_prepare)
{
send_error(thd, stmt->last_errno, stmt->last_error);
DBUG_VOID_RETURN;
}
init_stmt_execute(stmt);
if (stmt->param_count && setup_params_data(stmt))
DBUG_VOID_RETURN;
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),QUERY_PRIOR);
/*
TODO:
Also, have checks on basic executions such as mysql_insert(),
mysql_delete(), mysql_update() and mysql_select() to not to
have re-check on setup_* and other things ..
*/
stmt->thd->protocol= &thd->protocol_prep; // Switch to binary protocol
mysql_execute_command(stmt->thd);
stmt->thd->protocol= &thd->protocol_simple; // Use normal protocol
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(), WAIT_PRIOR);
DBUG_VOID_RETURN;
}
/*
Reset a prepared statement
SYNOPSIS
mysql_stmt_reset()
thd Thread handle
packet Packet with stmt handle
DESCRIPTION
This function is useful when one gets an error after calling
mysql_stmt_getlongdata() and one wants to reset the handle
so that one can call execute again.
*/
void mysql_stmt_reset(THD *thd, char *packet)
{
ulong stmt_id= uint4korr(packet);
PREP_STMT *stmt;
DBUG_ENTER("mysql_stmt_reset");
if (!(stmt=find_prepared_statement(thd, stmt_id, "close")))
{
send_error(thd);
DBUG_VOID_RETURN;
}
stmt->error_in_prepare= 0;
Item_param *item= *stmt->param, *end= item + stmt->param_count;
/* Free long data if used */
if (stmt->long_data_used)
{
stmt->long_data_used= 0;
for (; item < end ; item++)
item->reset();
}
DBUG_VOID_RETURN;
}
/*
Delete a prepared statement from memory
*/
void mysql_stmt_free(THD *thd, char *packet)
{
ulong stmt_id= uint4korr(packet);
PREP_STMT *stmt;
DBUG_ENTER("mysql_stmt_free");
if (!(stmt=find_prepared_statement(thd, stmt_id, "close")))
{
send_error(thd); // Not seen by the client
DBUG_VOID_RETURN;
}
my_free((char *)stmt->param, MYF(MY_ALLOW_ZERO_PTR));
tree_delete(&thd->prepared_statements, (void*) &stmt, (void *)0);
thd->last_prepared_stmt=0;
DBUG_VOID_RETURN;
}
/*
Long data in pieces from client
SYNOPSIS
mysql_stmt_get_longdata()
thd Thread handle
pos String to append
packet_length Length of string
DESCRIPTION
Get a part of a long data.
To make the protocol efficient, we are not sending any return packages
here.
If something goes wrong, then we will send the error on 'execute'
We assume that the client takes care of checking that all parts are sent
to the server. (No checking that we get a 'end of column' in the server)
*/
void mysql_stmt_get_longdata(THD *thd, char *pos, ulong packet_length)
{
PREP_STMT *stmt;
DBUG_ENTER("mysql_stmt_get_longdata");
/* The following should never happen */
if (packet_length < MYSQL_LONG_DATA_HEADER+1)
{
my_error(ER_WRONG_ARGUMENTS, MYF(0), "get_longdata");
DBUG_VOID_RETURN;
}
ulong stmt_id= uint4korr(pos);
uint param_number= uint2korr(pos+4);
pos+= MYSQL_LONG_DATA_HEADER; // Point to data
if (!(stmt=find_prepared_statement(thd, stmt_id, "get_longdata")))
{
/*
There is a chance that the client will never see this as
it doesn't expect an answer from this call...
*/
send_error(thd);
DBUG_VOID_RETURN;
}
if (param_number >= stmt->param_count)
{
/* Error will be sent in execute call */
stmt->error_in_prepare= 1;
stmt->last_errno= ER_WRONG_ARGUMENTS;
sprintf(stmt->last_error, ER(ER_WRONG_ARGUMENTS), "get_longdata");
DBUG_VOID_RETURN;
}
Item_param *param= *(stmt->param+param_number);
param->set_longdata(pos, packet_length-MYSQL_LONG_DATA_HEADER-1);
stmt->long_data_used= 1;
DBUG_VOID_RETURN;
}
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