86a4c3ba90
Fix to #473, http://bugs.skysql.com/show_bug.cgi?id=473 Several memory issues. Read the code. In general one-off hint is only added to gwbuf and freed in gwbuf_free. Stacked hint is copied to stack and to gwbuf. gwbuf is freed after routing but stacked hint is freed either in stop or when session is closed. All this applies to named hint as well except that in addition, it has one more copy in named hint struct which is emptied when session is closed.
115 lines
2.6 KiB
C
115 lines
2.6 KiB
C
#ifndef _MYSQLHINT_H
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#define _MYSQLHINT_H
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/*
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* This file is distributed as part of the SkySQL Gateway. It is free
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* software: you can redistribute it and/or modify it under the terms of the
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* GNU General Public License as published by the Free Software Foundation,
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* version 2.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program; if not, write to the Free Software Foundation, Inc., 51
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* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Copyright SkySQL Ab 2013
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*/
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/*
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* Revision History
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*
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* Date Who Description
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* 17-07-2014 Mark Riddoch Initial implementation
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*/
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#include <hint.h>
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/* Parser tokens for the hint parser */
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typedef enum {
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TOK_MAXSCALE = 1,
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TOK_PREPARE,
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TOK_START,
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TOK_STOP,
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TOK_EQUAL,
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TOK_STRING,
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TOK_ROUTE,
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TOK_TO,
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TOK_MASTER,
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TOK_SLAVE,
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TOK_SERVER,
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TOK_EOL
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} TOKEN_VALUE;
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/* The tokenising return type */
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typedef struct {
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TOKEN_VALUE token; // The token itself
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char *value; // The string version of the token
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} HINT_TOKEN;
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/**
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* A named hint set.
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*
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* The hint "MaxScale name PREPARE ..." can be used to defined a named set
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* of hints that can be later applied.
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*/
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typedef struct namedhints {
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char *name; /*< Hintsets name */
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HINT *hints;
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struct namedhints
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*next; /*< Next named hint */
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} NAMEDHINTS;
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/**
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* A session meaintains a stack of hints, the hints BEGIN and STOP are used
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* push hints on and off the stack. The current top of the stack is added to
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* any statement that does not explicitly define a hint for that signle
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* statement.
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*/
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typedef struct hintstack {
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HINT *hint;
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struct hintstack
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*next;
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} HINTSTACK;
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/**
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* The hint instance structure
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*/
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typedef struct {
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int sessions;
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} HINT_INSTANCE;
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/**
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* A hint parser session structure
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*/
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typedef struct {
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DOWNSTREAM down;
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GWBUF *request;
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int query_len;
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HINTSTACK *stack;
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NAMEDHINTS *named_hints; /* The named hints defined in this session */
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} HINT_SESSION;
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/* Some useful macros */
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#define CURRENT_HINT(session) ((session)->stack ? \
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(session)->stack->hints : NULL)
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/* Hint Parser State Machine */
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#define HS_INIT 0
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#define HS_ROUTE 1
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#define HS_ROUTE1 2
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#define HS_ROUTE_SERVER 3
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#define HS_NAME 4
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#define HS_PVALUE 5
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#define HS_PREPARE 6
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extern HINT *hint_parser(HINT_SESSION *session, GWBUF *request);
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NAMEDHINTS* free_named_hint(NAMEDHINTS* named_hint);
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HINTSTACK* free_hint_stack(HINTSTACK* hint_stack);
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#endif
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