bug #16017 (memory leaks in embedded server)

There actually was 3 different problems -
hash_user_connections wasn't cleaned
one strdupped database name wasn't freed
and stmt->mem_root wasn't cleaned as it was
replased with mysql->field_alloc for result
For the last one - i made the library using stmt's
fields to store result if it's the case.


include/mysql.h:
  statement pointer added to the advanced_command to be checked in
  embedded server
include/sql_common.h:
  stmt added to the cli_advanced_command interface
libmysql/libmysql.c:
  stmt pointer now sent to advanced_command
libmysqld/embedded_priv.h:
  it's enough to send database name to check_embedded_connection
libmysqld/lib_sql.cc:
  Now we store result directly in the MYSQL_STMT structure to
  avoid extra copying
libmysqld/libmysqld.c:
  it's enough to only send database pointer to check_embedded_connection
sql-common/client.c:
  stmt fake attribute added to cli_advanced_command
sql/sql_parse.cc:
  hash_user_connections isn't used if no access checks compiled

include/mysql.h

@@ -216,6 +216,7 @@ enum mysql_rpl_type
 };
 
 struct st_mysql_methods;
+struct st_mysql_stmt;
 
 typedef struct st_mysql
 {
@@ -269,6 +270,12 @@ typedef struct st_mysql
     from mysql_stmt_close if close had to cancel result set of this object.
   */
   my_bool *unbuffered_fetch_owner;
+  /*
+    In embedded server it points to the statement that is processed
+    in the current query. We store some results directly in statement
+    fields then.
+  */
+  struct st_mysql_stmt *current_stmt;
 } MYSQL;
 
 typedef struct st_mysql_res {
@@ -636,7 +643,8 @@ typedef struct st_mysql_methods
 			      unsigned long header_length,
 			      const char *arg,
 			      unsigned long arg_length,
-			      my_bool skip_check);
+			      my_bool skip_check,
+                              MYSQL_STMT *stmt);
   MYSQL_DATA *(*read_rows)(MYSQL *mysql,MYSQL_FIELD *mysql_fields,
 			   unsigned int fields);
   MYSQL_RES * (*use_result)(MYSQL *mysql);
@@ -724,8 +732,11 @@ int		STDCALL mysql_drop_db(MYSQL *mysql, const char *DB);
 */
 
 #define simple_command(mysql, command, arg, length, skip_check) \
-  (*(mysql)->methods->advanced_command)(mysql, command,         \
-					NullS, 0, arg, length, skip_check)
+  (*(mysql)->methods->advanced_command)(mysql, command, NullS,  \
+                                        0, arg, length, skip_check, NULL)
+#define stmt_command(mysql, command, arg, length, stmt) \
+  (*(mysql)->methods->advanced_command)(mysql, command, NullS,  \
+                                        0, arg, length, 1, stmt)
 unsigned long net_safe_read(MYSQL* mysql);
 
 #ifdef __NETWARE__

include/sql_common.h

@@ -33,7 +33,8 @@ void mysql_read_default_options(struct st_mysql_options *options,
 my_bool
 cli_advanced_command(MYSQL *mysql, enum enum_server_command command,
 		     const char *header, ulong header_length,
-		     const char *arg, ulong arg_length, my_bool skip_check);
+		     const char *arg, ulong arg_length, my_bool skip_check,
+                     MYSQL_STMT *stmt);
 
 void set_stmt_errmsg(MYSQL_STMT * stmt, const char *err, int errcode,
 		     const char *sqlstate);

libmysql/libmysql.c

@@ -2085,7 +2085,7 @@ mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, ulong length)
       mysql_use_result it won't be freed in mysql_stmt_free_result and
       we should get 'Commands out of sync' here.
     */
-    if (simple_command(mysql, COM_CLOSE_STMT, buff, 4, 1))
+    if (stmt_command(mysql, COM_CLOSE_STMT, buff, 4, stmt))
     {
       set_stmt_errmsg(stmt, mysql->net.last_error, mysql->net.last_errno,
                       mysql->net.sqlstate);
@@ -2094,7 +2094,7 @@ mysql_stmt_prepare(MYSQL_STMT *stmt, const char *query, ulong length)
     stmt->state= MYSQL_STMT_INIT_DONE;
   }
 
-  if (simple_command(mysql, COM_PREPARE, query, length, 1))
+  if (stmt_command(mysql, COM_PREPARE, query, length, stmt))
   {
     set_stmt_errmsg(stmt, mysql->net.last_error, mysql->net.last_errno,
                     mysql->net.sqlstate);
@@ -2505,7 +2505,7 @@ static my_bool execute(MYSQL_STMT *stmt, char *packet, ulong length)
   buff[4]= (char) 0;                            /* no flags */
   int4store(buff+5, 1);                         /* iteration count */
   if (cli_advanced_command(mysql, COM_EXECUTE, buff, sizeof(buff),
-                           packet, length, 1) ||
+                           packet, length, 1, NULL) ||
       (*mysql->methods->read_query_result)(mysql))
   {
     set_stmt_errmsg(stmt, net->last_error, net->last_errno, net->sqlstate);
@@ -3279,7 +3279,8 @@ mysql_stmt_send_long_data(MYSQL_STMT *stmt, uint param_number,
       This is intentional to save bandwidth.
     */
     if ((*mysql->methods->advanced_command)(mysql, COM_LONG_DATA, buff,
-					    sizeof(buff), data, length, 1))
+					    sizeof(buff), data, length, 1,
+                                            NULL))
     {
       set_stmt_errmsg(stmt, mysql->net.last_error,
 		      mysql->net.last_errno, mysql->net.sqlstate);
@@ -4603,7 +4604,7 @@ my_bool STDCALL mysql_stmt_close(MYSQL_STMT *stmt)
         mysql->status= MYSQL_STATUS_READY;
       }
       int4store(buff, stmt->stmt_id);
-      if ((rc= simple_command(mysql, COM_CLOSE_STMT, buff, 4, 1)))
+      if ((rc= stmt_command(mysql, COM_CLOSE_STMT, buff, 4, stmt)))
       {
         set_stmt_errmsg(stmt, mysql->net.last_error, mysql->net.last_errno,
                         mysql->net.sqlstate);
@@ -4641,7 +4642,7 @@ my_bool STDCALL mysql_stmt_reset(MYSQL_STMT *stmt)
   mysql= stmt->mysql->last_used_con;
   int4store(buff, stmt->stmt_id);		/* Send stmt id to server */
   if ((*mysql->methods->advanced_command)(mysql, COM_RESET_STMT, buff,
-                                          sizeof(buff), 0, 0, 0))
+                                          sizeof(buff), 0, 0, 0, 0))
   {
     set_stmt_errmsg(stmt, mysql->net.last_error, mysql->net.last_errno,
                     mysql->net.sqlstate);

libmysqld/embedded_priv.h

@@ -24,9 +24,9 @@
 
 C_MODE_START
 void lib_connection_phase(NET *net, int phase);
-void init_embedded_mysql(MYSQL *mysql, int client_flag, char *db);
-void *create_embedded_thd(int client_flag, char *db);
-int check_embedded_connection(MYSQL *mysql);
+void init_embedded_mysql(MYSQL *mysql, int client_flag);
+void *create_embedded_thd(int client_flag);
+int check_embedded_connection(MYSQL *mysql, const char *db);
 void free_old_query(MYSQL *mysql);
 void embedded_get_error(MYSQL *mysql);
 extern MYSQL_METHODS embedded_methods;

libmysqld/lib_sql.cc

@@ -47,6 +47,7 @@ C_MODE_START
 #include "errmsg.h"
 #include <sql_common.h>
 
+
 void embedded_get_error(MYSQL *mysql)
 {
   THD *thd=(THD *) mysql->thd;
@@ -66,7 +67,8 @@ void embedded_get_error(MYSQL *mysql)
 static my_bool
 emb_advanced_command(MYSQL *mysql, enum enum_server_command command,
 		     const char *header, ulong header_length,
-		     const char *arg, ulong arg_length, my_bool skip_check)
+		     const char *arg, ulong arg_length, my_bool skip_check,
+                     MYSQL_STMT *stmt)
 {
   my_bool result= 1;
   THD *thd=(THD *) mysql->thd;
@@ -90,6 +92,7 @@ emb_advanced_command(MYSQL *mysql, enum enum_server_command command,
   mysql->affected_rows= ~(my_ulonglong) 0;
   mysql->field_count= 0;
   net->last_errno= 0;
+  mysql->current_stmt= stmt;
 
   thd->store_globals();				// Fix if more than one connect
   /* 
@@ -183,7 +186,6 @@ static my_bool emb_read_prepare_result(MYSQL *mysql, MYSQL_STMT *stmt)
       mysql->server_status|= SERVER_STATUS_IN_TRANS;
 
     stmt->fields= mysql->fields;
-    stmt->mem_root= mysql->field_alloc;
     mysql->fields= NULL;
   }
 
@@ -225,7 +227,7 @@ static int emb_stmt_execute(MYSQL_STMT *stmt)
   thd->client_param_count= stmt->param_count;
   thd->client_params= stmt->params;
   if (emb_advanced_command(stmt->mysql, COM_EXECUTE,0,0,
-                           header, sizeof(header), 1) ||
+                           header, sizeof(header), 1, stmt) ||
       emb_mysql_read_query_result(stmt->mysql))
   {
     NET *net= &stmt->mysql->net;
@@ -242,8 +244,6 @@ int emb_read_binary_rows(MYSQL_STMT *stmt)
   MYSQL_DATA *data;
   if (!(data= emb_read_rows(stmt->mysql, 0, 0)))
     return 1;
-  stmt->result= *data;
-  my_free((char *) data, MYF(0));
   return 0;
 }
 
@@ -298,7 +298,8 @@ my_bool emb_next_result(MYSQL *mysql)
   DBUG_ENTER("emb_next_result");
 
   if (emb_advanced_command(mysql, COM_QUERY,0,0,
-			   thd->query_rest.ptr(),thd->query_rest.length(),1) ||
+			   thd->query_rest.ptr(),
+                           thd->query_rest.length(),1, 0) ||
       emb_mysql_read_query_result(mysql))
     DBUG_RETURN(1);
 
@@ -482,14 +483,14 @@ void end_embedded_server()
 } /* extern "C" */
 
 C_MODE_START
-void init_embedded_mysql(MYSQL *mysql, int client_flag, char *db)
+void init_embedded_mysql(MYSQL *mysql, int client_flag)
 {
   THD *thd = (THD *)mysql->thd;
   thd->mysql= mysql;
   mysql->server_version= server_version;
 }
 
-void *create_embedded_thd(int client_flag, char *db)
+void *create_embedded_thd(int client_flag)
 {
   THD * thd= new THD;
   thd->thread_id= thread_id++;
@@ -515,8 +516,8 @@ void *create_embedded_thd(int client_flag, char *db)
   thd->init_for_queries();
   thd->client_capabilities= client_flag;
 
-  thd->db= db;
-  thd->db_length= db ? strip_sp(db) : 0;
+  thd->db= NULL;
+  thd->db_length= 0;
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   thd->db_access= DB_ACLS;
   thd->master_access= ~NO_ACCESS;
@@ -533,18 +534,18 @@ err:
 }
 
 #ifdef NO_EMBEDDED_ACCESS_CHECKS
-int check_embedded_connection(MYSQL *mysql)
+int check_embedded_connection(MYSQL *mysql, const char *db)
 {
   THD *thd= (THD*)mysql->thd;
   thd->host= (char*)my_localhost;
   thd->host_or_ip= thd->host;
   thd->user= my_strdup(mysql->user, MYF(0));
   thd->priv_user= thd->user;
-  return check_user(thd, COM_CONNECT, NULL, 0, thd->db, true);
+  return check_user(thd, COM_CONNECT, NULL, 0, db, true);
 }
 
 #else
-int check_embedded_connection(MYSQL *mysql)
+int check_embedded_connection(MYSQL *mysql, const char *db)
 {
   THD *thd= (THD*)mysql->thd;
   int result;
@@ -578,7 +579,7 @@ int check_embedded_connection(MYSQL *mysql)
     passwd_len= 0;
 
   if((result= check_user(thd, COM_CONNECT, 
-			 scramble_buff, passwd_len, thd->db, true)))
+			 scramble_buff, passwd_len, db, true)))
      goto err;
 
   return 0;
@@ -636,8 +637,9 @@ bool Protocol::send_fields(List<Item> *list, uint flag)
     DBUG_RETURN(0);
 
   field_count= list->elements;
-  field_alloc= &mysql->field_alloc;
-  if (!(client_field= thd->mysql->fields= 
+  field_alloc= mysql->current_stmt ? &mysql->current_stmt->mem_root :
+                                     &mysql->field_alloc;
+  if (!(client_field= mysql->fields= 
 	(MYSQL_FIELD *)alloc_root(field_alloc, 
 				  sizeof(MYSQL_FIELD) * field_count)))
     goto err;
@@ -707,7 +709,7 @@ bool Protocol::send_fields(List<Item> *list, uint flag)
     client_field->max_length= 0;
     ++client_field;
   }
-  thd->mysql->field_count= field_count;
+  mysql->field_count= field_count;
 
   DBUG_RETURN(prepare_for_send(list));
  err:
@@ -736,13 +738,20 @@ bool Protocol_prep::write()
 
   if (!data)
   {
-    if (!(data= (MYSQL_DATA*) my_malloc(sizeof(MYSQL_DATA),
-					MYF(MY_WME | MY_ZEROFILL))))
-      return true;
+    MYSQL *mysql= thd->mysql;
+
+    if (mysql->current_stmt)
+      data= &mysql->current_stmt->result;
+    else
+    {
+      if (!(data= (MYSQL_DATA*) my_malloc(sizeof(MYSQL_DATA),
+                                          MYF(MY_WME | MY_ZEROFILL))))
+        return true;
     
+      init_alloc_root(&data->alloc,8192,0);	/* Assume rowlength < 8192 */
+      data->alloc.min_malloc=sizeof(MYSQL_ROWS);
+    }
     alloc= &data->alloc;
-    init_alloc_root(alloc,8192,0);	/* Assume rowlength < 8192 */
-    alloc->min_malloc=sizeof(MYSQL_ROWS);
     data->rows=0;
     data->fields=field_count;
     data->prev_ptr= &data->data;

libmysqld/libmysqld.c

@@ -134,7 +134,6 @@ mysql_real_connect(MYSQL *mysql,const char *host, const char *user,
 		   const char *passwd, const char *db,
 		   uint port, const char *unix_socket,ulong client_flag)
 {
-  char *db_name;
   char name_buff[USERNAME_LENGTH];
 
   DBUG_ENTER("mysql_real_connect");
@@ -197,13 +196,11 @@ mysql_real_connect(MYSQL *mysql,const char *host, const char *user,
 
   port=0;
   unix_socket=0;
-  db_name = db ? my_strdup(db,MYF(MY_WME)) : NULL;
+  mysql->thd= create_embedded_thd(client_flag);
 
-  mysql->thd= create_embedded_thd(client_flag, db_name);
+  init_embedded_mysql(mysql, client_flag);
 
-  init_embedded_mysql(mysql, client_flag, db_name);
-
-  if (check_embedded_connection(mysql))
+  if (check_embedded_connection(mysql, db))
     goto error;
 
   if (mysql_init_charset(mysql))

sql-common/client.c

@@ -648,7 +648,8 @@ void free_rows(MYSQL_DATA *cur)
 my_bool
 cli_advanced_command(MYSQL *mysql, enum enum_server_command command,
 		     const char *header, ulong header_length,
-		     const char *arg, ulong arg_length, my_bool skip_check)
+		     const char *arg, ulong arg_length, my_bool skip_check,
+                     MYSQL_STMT *stmt __attribute__((unused)))
 {
   NET *net= &mysql->net;
   my_bool result= 1;

sql/sql_parse.cc

@@ -54,8 +54,8 @@ extern "C" int gethostname(char *name, int namelen);
 static void time_out_user_resource_limits(THD *thd, USER_CONN *uc);
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
 static int check_for_max_user_connections(THD *thd, USER_CONN *uc);
-#endif
 static void decrease_user_connections(USER_CONN *uc);
+#endif /* NO_EMBEDDED_ACCESS_CHECKS */
 static bool check_db_used(THD *thd,TABLE_LIST *tables);
 static bool check_multi_update_lock(THD *thd, TABLE_LIST *tables, 
 				    List<Item> *fields, SELECT_LEX *select_lex);
@@ -137,6 +137,7 @@ inline bool all_tables_not_ok(THD *thd, TABLE_LIST *tables)
 #endif
 
 
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
 static HASH hash_user_connections;
 
 static int get_or_create_user_conn(THD *thd, const char *user,
@@ -190,6 +191,7 @@ end:
   return return_val;
 
 }
+#endif /* !NO_EMBEDDED_ACCESS_CHECKS */
 
 
 /*
@@ -231,11 +233,7 @@ int check_user(THD *thd, enum enum_server_command command,
     thd->db= 0;
     thd->db_length= 0;
     if (mysql_change_db(thd, db))
-    {
-      if (thd->user_connect)
-	decrease_user_connections(thd->user_connect);
       DBUG_RETURN(-1);
-    }
   }
   else
     send_ok(thd);
@@ -409,10 +407,12 @@ extern "C" void free_user(struct user_conn *uc)
 
 void init_max_user_conn(void)
 {
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
   (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);
+#endif
 }
 
 
@@ -466,7 +466,6 @@ static int check_for_max_user_connections(THD *thd, USER_CONN *uc)
   (void) pthread_mutex_unlock(&LOCK_user_conn);
   DBUG_RETURN(error);
 }
-#endif /* NO_EMBEDDED_ACCESS_CHECKS */
 
 /*
   Decrease user connection count
@@ -500,13 +499,18 @@ static void decrease_user_connections(USER_CONN *uc)
   DBUG_VOID_RETURN;
 }
 
+#endif /* NO_EMBEDDED_ACCESS_CHECKS */
+
 
 void free_max_user_conn(void)
 {
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
   hash_free(&hash_user_connections);
+#endif /* NO_EMBEDDED_ACCESS_CHECKS */
 }
 
 
+
 /*
   Mark all commands that somehow changes a table
   This is used to check number of updates / hour
@@ -1476,9 +1480,11 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
     }
     else
     {
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
       /* we've authenticated new user */
       if (save_user_connect)
 	decrease_user_connections(save_user_connect);
+#endif /* NO_EMBEDDED_ACCESS_CHECKS */
       x_free((gptr) save_db);
       x_free((gptr) save_user);
     }