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WL#1622 "SQL Syntax for Prepared Statements": post-review fixes:

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Moved PS name to Statement class, Statement_map now handles name-to-statement resolution.
  Both named and unnamed statements are now executed in one function (sql_prepare.cc:execute_stmt)
  Fixed a problem: Malformed sequence of commands from client could cause server to use previously deleted objects.
  Some code cleanup and small fixes
This commit is contained in:
sergefp@mysql.com
2004-04-13 01:58:48 +04:00
parent eef8fbcf9e
commit a314cbefa1
5 changed files with 150 additions and 166 deletions
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7
sql/mysql_priv.h
View File

@ -613,11 +613,10 @@ int mysqld_show_column_types(THD *thd);
int mysqld_help (THD *thd, const char *text);
/* sql_prepare.cc */
class Prepared_statement;
Prepared_statement *mysql_stmt_prepare(THD *thd, char *packet,
uint packet_length, bool text_protocol=false);
int mysql_stmt_prepare(THD *thd, char *packet, uint packet_length,
LEX_STRING *name=NULL);
void mysql_stmt_execute(THD *thd, char *packet, uint packet_length);
void mysql_sql_stmt_execute(THD *thd, Prepared_statement *stmt);
void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name);
void mysql_stmt_free(THD *thd, char *packet);
void mysql_stmt_reset(THD *thd, char *packet);
void mysql_stmt_get_longdata(THD *thd, char *pos, ulong packet_length);

62
sql/sql_class.cc
View File

@ -78,24 +78,6 @@ extern "C" void free_user_var(user_var_entry *entry)
my_free((char*) entry,MYF(0));
}
/****************************************************************************
** SQL syntax names for Prepared Statements
****************************************************************************/
extern "C" byte *get_stmt_key(SQL_PREP_STMT_ENTRY *entry, uint *length,
my_bool not_used __attribute__((unused)))
{
*length=(uint) entry->name.length;
return (byte*) entry->name.str;
}
extern "C" void free_sql_stmt(SQL_PREP_STMT_ENTRY *entry)
{
char *pos= (char*) entry+ALIGN_SIZE(sizeof(*entry));
my_free((char*) entry,MYF(0));
}
/****************************************************************************
** Thread specific functions
****************************************************************************/
@ -178,9 +160,6 @@ THD::THD():user_time(0), current_statement(0), is_fatal_error(0),
else
bzero((char*) &user_var_events, sizeof(user_var_events));
hash_init(&sql_prepared_stmts, &my_charset_bin, USER_VARS_HASH_SIZE, 0, 0,
(hash_get_key) get_stmt_key,
(hash_free_key) free_sql_stmt,0);
/* Protocol */
protocol= &protocol_simple; // Default protocol
protocol_simple.init(this);
@ -299,7 +278,6 @@ void THD::cleanup(void)
my_free((char*) variables.datetime_format, MYF(MY_ALLOW_ZERO_PTR));
delete_dynamic(&user_var_events);
hash_free(&user_vars);
hash_free(&sql_prepared_stmts);
if (global_read_lock)
unlock_global_read_lock(this);
if (ull)
@ -1220,6 +1198,7 @@ Statement::Statement(THD *thd)
query_length(0),
free_list(0)
{
name.str= NULL;
init_sql_alloc(&mem_root,
thd->variables.query_alloc_block_size,
thd->variables.query_prealloc_size);
@ -1303,17 +1282,52 @@ static void delete_statement_as_hash_key(void *key)
delete (Statement *) key;
}
byte *get_stmt_name_hash_key(Statement *entry, uint *length,
my_bool not_used __attribute__((unused)))
{
*length=(uint) entry->name.length;
return (byte*) entry->name.str;
}
C_MODE_END
Statement_map::Statement_map() :
last_found_statement(0)
{
enum { START_HASH_SIZE = 16 };
hash_init(&st_hash, default_charset_info, START_HASH_SIZE, 0, 0,
enum
{
START_STMT_HASH_SIZE = 16,
START_NAME_HASH_SIZE = 16
};
hash_init(&st_hash, default_charset_info, START_STMT_HASH_SIZE, 0, 0,
get_statement_id_as_hash_key,
delete_statement_as_hash_key, MYF(0));
hash_init(&names_hash, &my_charset_bin, START_NAME_HASH_SIZE, 0, 0,
(hash_get_key) get_stmt_name_hash_key,
NULL,MYF(0));
}
int Statement_map::insert(Statement *statement)
{
int rc= my_hash_insert(&st_hash, (byte *) statement);
if (rc == 0)
last_found_statement= statement;
if (statement->name.str)
{
/*
If there is a statement with the same name, remove it. It is ok to
remove old and fail to insert new one at the same time.
*/
Statement *old_stmt;
if ((old_stmt= find_by_name(&statement->name)))
erase(old_stmt);
if ((rc= my_hash_insert(&names_hash, (byte*)statement)))
hash_delete(&st_hash, (byte*)statement);
}
return rc;
}
bool select_dumpvar::send_data(List<Item> &items)
{
List_iterator_fast<Item_func_set_user_var> li(vars);

43
sql/sql_class.h
View File

@ -456,6 +456,7 @@ public:
*/
bool allow_sum_func;
LEX_STRING name; /* name for named prepared statements */
LEX *lex; // parse tree descriptor
/*
Points to the query associated with this statement. It's const, but
@ -522,8 +523,14 @@ public:
/*
Used to seek all existing statements in the connection
Deletes all statements in destructor.
Container for all statements created/used in a connection.
Statements in Statement_map have unique Statement::id (guaranteed by id
assignment in Statement::Statement)
Non-empty statement names are unique too: attempt to insert a new statement
with duplicate name causes older statement to be deleted
Statements are auto-deleted when they are removed from the map and when the
map is deleted.
*/
class Statement_map
@ -531,12 +538,14 @@ class Statement_map
public:
Statement_map();
int insert(Statement *statement)
int insert(Statement *statement);
Statement *find_by_name(LEX_STRING *name)
{
int rc= my_hash_insert(&st_hash, (byte *) statement);
if (rc == 0)
last_found_statement= statement;
return rc;
Statement *stmt;
stmt= (Statement*)hash_search(&names_hash, (byte*)name->str,
name->length);
return stmt;
}
Statement *find(ulong id)
@ -550,15 +559,21 @@ public:
{
if (statement == last_found_statement)
last_found_statement= 0;
if (statement->name.str)
{
hash_delete(&names_hash, (byte *) statement);
}
hash_delete(&st_hash, (byte *) statement);
}
~Statement_map()
{
hash_free(&st_hash);
hash_free(&names_hash);
}
private:
HASH st_hash;
HASH names_hash;
Statement *last_found_statement;
};
@ -594,12 +609,6 @@ public:
struct system_variables variables; // Changeable local variables
pthread_mutex_t LOCK_delete; // Locked before thd is deleted
/*
statement_name -> (Statement*) map of statements prepared using SQL syntax.
Hash element is SQL_PREP_STMT_ENTRY.
*/
HASH sql_prepared_stmts;
/* all prepared statements and cursors of this connection */
Statement_map stmt_map;
/*
@ -1276,14 +1285,6 @@ class user_var_entry
DTCollation collation;
};
class Prepared_statement;
/* Needed by THD::sql_prepared_stmts */
typedef struct st_sql_prep_stmt_entry
{
public:
LEX_STRING name;
Prepared_statement *stmt;
}SQL_PREP_STMT_ENTRY;
/* Class for unique (removing of duplicates) */

85
sql/sql_parse.cc
View File

@ -1961,87 +1961,40 @@ mysql_execute_command(THD *thd)
}
case SQLCOM_PREPARE:
{
char *stmt_name= lex->prepared_stmt_name.str;
uint name_len= lex->prepared_stmt_name.length;
Prepared_statement *stmt;
SQL_PREP_STMT_ENTRY *entry;
DBUG_PRINT("info", ("PREPARE: %.*s FROM '%.*s' \n", name_len, stmt_name,
DBUG_PRINT("info", ("PREPARE: %.*s FROM '%.*s' \n",
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str,
lex->prepared_stmt_code.length,
lex->prepared_stmt_code.str));
if ((entry=(SQL_PREP_STMT_ENTRY*)hash_search(&thd->sql_prepared_stmts,
(byte*)stmt_name, name_len)))
{
/* Free the statement with the same name and reuse hash entry */
thd->stmt_map.erase((Statement*)entry->stmt);
}
else
{
uint size=ALIGN_SIZE(sizeof(SQL_PREP_STMT_ENTRY))+name_len+1;
if (!hash_inited(&thd->sql_prepared_stmts) ||
!(entry= (SQL_PREP_STMT_ENTRY*)my_malloc(size,MYF(MY_WME))))
{
send_error(thd, ER_OUT_OF_RESOURCES);
break;
}
entry->name.str= (char*)entry + ALIGN_SIZE(sizeof(SQL_PREP_STMT_ENTRY));
entry->name.length= name_len;
memcpy(entry->name.str, stmt_name, name_len+1);
if (my_hash_insert(&thd->sql_prepared_stmts, (byte*)entry))
{
my_free((char*)entry,MYF(0));
send_error(thd, ER_OUT_OF_RESOURCES);
break;
}
}
/* Pretend this is a COM_PREPARE query so parser allows placeholders etc*/
thd->command= COM_PREPARE;
/* 'length+1' is for alloc_query that strips the last character */
stmt= mysql_stmt_prepare(thd, lex->prepared_stmt_code.str,
lex->prepared_stmt_code.length + 1, true);
if (stmt)
{
entry->stmt= stmt;
if (!mysql_stmt_prepare(thd, lex->prepared_stmt_code.str,
lex->prepared_stmt_code.length + 1,
&lex->prepared_stmt_name))
send_ok(thd, 0L, 0L, "Statement prepared");
}
else
hash_delete(&thd->sql_prepared_stmts, (byte*)entry);
break;
}
case SQLCOM_EXECUTE:
{
char *stmt_name= lex->prepared_stmt_name.str;
uint name_len= lex->prepared_stmt_name.length;
SQL_PREP_STMT_ENTRY *entry;
DBUG_PRINT("info", ("EXECUTE: %.*s\n", name_len, stmt_name));
if (!(entry= (SQL_PREP_STMT_ENTRY*)hash_search(&thd->sql_prepared_stmts,
(byte*)stmt_name,
name_len)))
{
send_error(thd, ER_UNKNOWN_STMT_HANDLER, "Undefined prepared statement");
lex->prepared_stmt_params.empty();
break;
}
mysql_sql_stmt_execute(thd, entry->stmt);
DBUG_PRINT("info", ("EXECUTE: %.*s\n",
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str));
mysql_sql_stmt_execute(thd, &lex->prepared_stmt_name);
lex->prepared_stmt_params.empty();
break;
}
case SQLCOM_DEALLOCATE_PREPARE:
{
char *stmt_name= lex->prepared_stmt_name.str;
uint name_len= lex->prepared_stmt_name.length;
SQL_PREP_STMT_ENTRY *entry;
DBUG_PRINT("info", ("DEALLOCATE PREPARE: %.*s\n", name_len, stmt_name));
if (!(entry= (SQL_PREP_STMT_ENTRY*)hash_search(&thd->sql_prepared_stmts,
(byte*)stmt_name,
name_len)))
Statement* stmt;
DBUG_PRINT("info", ("DEALLOCATE PREPARE: %.*s\n",
lex->prepared_stmt_name.length,
lex->prepared_stmt_name.str));
if ((stmt= thd->stmt_map.find_by_name(&lex->prepared_stmt_name)))
{
send_error(thd, ER_UNKNOWN_STMT_HANDLER, "Undefined prepared statement");
break;
thd->stmt_map.erase(stmt);
send_ok(thd);
}
thd->stmt_map.erase((Statement*)entry->stmt);
hash_delete(&thd->sql_prepared_stmts, (byte*)entry);
send_ok(thd);
else
send_error(thd,ER_UNKNOWN_STMT_HANDLER,"Undefined prepared statement");
break;
}
case SQLCOM_DO:

111
sql/sql_prepare.cc
View File

@ -107,6 +107,7 @@ public:
virtual Statement::Type type() const;
};
static void execute_stmt(THD *thd, Prepared_statement *stmt);
/******************************************************************************
Implementation
@ -636,7 +637,6 @@ static bool emb_insert_params_withlog(Prepared_statement *stmt)
/*
Set prepared statement parameters from user variables.
Also replace '?' marks with values in thd->query if binary logging is on.
SYNOPSIS
insert_params_from_vars()
stmt Statement
@ -682,11 +682,7 @@ static bool insert_params_from_vars(Prepared_statement *stmt,
}
}
else
{
param->item_result_type= INT_RESULT;
param->maybe_null= param->null_value= 1;
param->value_is_set= 0;
}
param->maybe_null= param->null_value= param->value_is_set= 1;
}
DBUG_RETURN(0);
}
@ -704,6 +700,8 @@ static bool insert_params_from_vars_with_log(Prepared_statement *stmt,
String str, query;
const String *res;
uint32 length= 0;
if (query.copy(stmt->query, stmt->query_length, default_charset_info))
DBUG_RETURN(1);
for (Item_param **it= begin; it < end; ++it)
{
@ -734,9 +732,7 @@ static bool insert_params_from_vars_with_log(Prepared_statement *stmt,
}
else
{
param->item_result_type= INT_RESULT;
param->maybe_null= param->null_value= 1;
param->value_is_set= 0;
param->maybe_null= param->null_value= param->value_is_set= 1;
res= &my_null_string;
}
@ -1089,6 +1085,14 @@ static bool init_param_array(Prepared_statement *stmt)
/*
SYNOPSIS
mysql_stmt_prepare()
packet Prepared query
packet_length query length, with ignored trailing NULL or quote char.
name NULL or statement name. For unnamed statements binary PS
protocol is used, for named statmenents text protocol is
used.
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. without any log/disk
@ -1103,8 +1107,8 @@ static bool init_param_array(Prepared_statement *stmt)
*/
Prepared_statement *mysql_stmt_prepare(THD *thd, char *packet,
uint packet_length, bool text_protocol)
int mysql_stmt_prepare(THD *thd, char *packet, uint packet_length,
LEX_STRING *name)
{
LEX *lex;
Prepared_statement *stmt= new Prepared_statement(thd);
@ -1116,14 +1120,26 @@ Prepared_statement *mysql_stmt_prepare(THD *thd, char *packet,
if (stmt == 0)
{
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_RETURN(NULL);
DBUG_RETURN(1);
}
if (name)
{
stmt->name.length= name->length;
if (!(stmt->name.str= my_memdup((byte*)name->str, name->length,
MYF(MY_WME))))
{
delete stmt;
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_RETURN(1);
}
}
if (thd->stmt_map.insert(stmt))
{
delete stmt;
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_RETURN(NULL);
DBUG_RETURN(1);
}
thd->stmt_backup.set_statement(thd);
@ -1140,7 +1156,7 @@ Prepared_statement *mysql_stmt_prepare(THD *thd, char *packet,
/* Statement map deletes statement on erase */
thd->stmt_map.erase(stmt);
send_error(thd, ER_OUT_OF_RESOURCES);
DBUG_RETURN(NULL);
DBUG_RETURN(1);
}
mysql_log.write(thd, COM_PREPARE, "%s", packet);
@ -1152,7 +1168,7 @@ Prepared_statement *mysql_stmt_prepare(THD *thd, char *packet,
error= yyparse((void *)thd) || thd->is_fatal_error ||
init_param_array(stmt) ||
send_prepare_results(stmt, text_protocol);
send_prepare_results(stmt, test(name));
/* restore to WAIT_PRIOR: QUERY_PRIOR is set inside alloc_query */
if (!(specialflag & SPECIAL_NO_PRIOR))
@ -1183,7 +1199,7 @@ Prepared_statement *mysql_stmt_prepare(THD *thd, char *packet,
sl->prep_where= sl->where;
}
}
DBUG_RETURN(stmt);
DBUG_RETURN(!stmt);
}
/* Reinit statement before execution */
@ -1236,6 +1252,7 @@ static void reset_stmt_for_execute(Prepared_statement *stmt)
}
}
/*
Executes previously prepared query.
If there is any parameters, then replace markers with the data supplied
@ -1267,11 +1284,6 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
DBUG_VOID_RETURN;
}
thd->stmt_backup.set_statement(thd);
thd->set_statement(stmt);
reset_stmt_for_execute(stmt);
#ifndef EMBEDDED_LIBRARY
if (stmt->param_count)
{
@ -1289,30 +1301,12 @@ void mysql_stmt_execute(THD *thd, char *packet, uint packet_length)
if (stmt->param_count && stmt->set_params_data(stmt))
goto set_params_data_err;
#endif
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 ..
*/
thd->protocol= &thd->protocol_prep; // Switch to binary protocol
mysql_execute_command(thd);
execute_stmt(thd, stmt);
thd->protocol= &thd->protocol_simple; // Use normal protocol
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(), WAIT_PRIOR);
cleanup_items(stmt->free_list);
close_thread_tables(thd); // to close derived tables
thd->set_statement(&thd->stmt_backup);
DBUG_VOID_RETURN;
set_params_data_err:
thd->set_statement(&thd->stmt_backup);
my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_execute");
send_error(thd);
DBUG_VOID_RETURN;
@ -1324,28 +1318,48 @@ set_params_data_err:
lex->prepared_stmt_params and send result to the client using text protocol.
*/
void mysql_sql_stmt_execute(THD *thd, Prepared_statement *stmt)
void mysql_sql_stmt_execute(THD *thd, LEX_STRING *stmt_name)
{
Prepared_statement *stmt;
DBUG_ENTER("mysql_stmt_execute");
if (!(stmt= (Prepared_statement*)thd->stmt_map.find_by_name(stmt_name)))
{
send_error(thd, ER_UNKNOWN_STMT_HANDLER,
"Undefined prepared statement");
DBUG_VOID_RETURN;
}
if (stmt->param_count != thd->lex->prepared_stmt_params.elements)
{
my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_execute");
send_error(thd);
DBUG_VOID_RETURN;
}
thd->stmt_backup.set_statement(thd);
thd->set_statement(stmt);
reset_stmt_for_execute(stmt);
/* Item_param allows setting parameters in COM_EXECUTE only */
thd->command= COM_EXECUTE;
if (stmt->set_params_from_vars(stmt, thd->stmt_backup.lex->
prepared_stmt_params))
if (stmt->set_params_from_vars(stmt, thd->lex->prepared_stmt_params))
{
thd->set_statement(&thd->stmt_backup);
my_error(ER_WRONG_ARGUMENTS, MYF(0), "mysql_execute");
send_error(thd);
}
execute_stmt(thd, stmt);
DBUG_VOID_RETURN;
}
/*
Execute prepared statement.
Caller must set parameter values and thd::protocol.
*/
static void execute_stmt(THD *thd, Prepared_statement *stmt)
{
DBUG_ENTER("execute_stmt");
thd->stmt_backup.set_statement(thd);
thd->set_statement(stmt);
reset_stmt_for_execute(stmt);
if (!(specialflag & SPECIAL_NO_PRIOR))
my_pthread_setprio(pthread_self(),QUERY_PRIOR);
mysql_execute_command(thd);
@ -1359,6 +1373,7 @@ void mysql_sql_stmt_execute(THD *thd, Prepared_statement *stmt)
}
/*
Reset a prepared statement, in case there was an error in send_longdata.
Note: we don't send any reply to that command.
@ -1522,6 +1537,8 @@ Prepared_statement::Prepared_statement(THD *thd_arg)
Prepared_statement::~Prepared_statement()
{
free_items(free_list);
if (name.str)
my_free(name.str, MYF(0));
}