152 lines
4.3 KiB
C
152 lines
4.3 KiB
C
/*
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* Copyright (c) 2016 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2019-07-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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#include "sharding_common.h"
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#include <maxscale/alloc.h>
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#include <maxscale/poll.h>
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/**
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* Extract the database name from a COM_INIT_DB or literal USE ... query.
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* @param buf Buffer with the database change query
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* @param str Pointer where the database name is copied
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* @return True for success, false for failure
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*/
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bool extract_database(GWBUF* buf, char* str)
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{
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uint8_t* packet;
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char *saved, *tok, *query = NULL;
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bool succp = true;
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unsigned int plen;
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packet = GWBUF_DATA(buf);
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plen = gw_mysql_get_byte3(packet) - 1;
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/** Copy database name from MySQL packet to session */
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if (qc_get_operation(buf) == QUERY_OP_CHANGE_DB)
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{
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const char *delim = "` \n\t;";
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query = modutil_get_SQL(buf);
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tok = strtok_r(query, delim, &saved);
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if (tok == NULL || strcasecmp(tok, "use") != 0)
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{
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MXS_ERROR("extract_database: Malformed chage database packet.");
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succp = false;
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goto retblock;
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}
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tok = strtok_r(NULL, delim, &saved);
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if (tok == NULL)
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{
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MXS_ERROR("extract_database: Malformed change database packet.");
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succp = false;
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goto retblock;
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}
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strncpy(str, tok, MYSQL_DATABASE_MAXLEN);
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}
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else
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{
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memcpy(str, packet + 5, plen);
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memset(str + plen, 0, 1);
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}
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retblock:
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MXS_FREE(query);
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return succp;
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}
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/**
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* Create a fake error message from a DCB.
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* @param fail_str Custom error message
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* @param dcb DCB to use as the origin of the error
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*/
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void create_error_reply(char* fail_str, DCB* dcb)
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{
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MXS_INFO("change_current_db: failed to change database: %s", fail_str);
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GWBUF* errbuf = modutil_create_mysql_err_msg(1, 0, 1049, "42000", fail_str);
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if (errbuf == NULL)
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{
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MXS_ERROR("Creating buffer for error message failed.");
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return;
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}
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/** Set flags that help router to identify session commands reply */
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gwbuf_set_type(errbuf, GWBUF_TYPE_MYSQL);
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gwbuf_set_type(errbuf, GWBUF_TYPE_SESCMD_RESPONSE);
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gwbuf_set_type(errbuf, GWBUF_TYPE_RESPONSE_END);
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poll_add_epollin_event_to_dcb(dcb,
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errbuf);
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}
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/**
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* Read new database name from MYSQL_COM_INIT_DB packet or a literal USE ... COM_QUERY
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* packet, check that it exists in the hashtable and copy its name to MYSQL_session.
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*
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* @param dest Destination where the database name will be written
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* @param dbhash Hashtable containing valid databases
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* @param buf Buffer containing the database change query
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*
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* @return true if new database is set, false if non-existent database was tried
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* to be set
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*/
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bool change_current_db(char* dest,
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HASHTABLE* dbhash,
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GWBUF* buf)
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{
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char* target;
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bool succp;
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char db[MYSQL_DATABASE_MAXLEN + 1];
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if (GWBUF_LENGTH(buf) <= MYSQL_DATABASE_MAXLEN - 5)
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{
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/** Copy database name from MySQL packet to session */
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if (!extract_database(buf, db))
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{
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succp = false;
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goto retblock;
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}
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MXS_INFO("change_current_db: INIT_DB with database '%s'", db);
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/**
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* Update the session's active database only if it's in the hashtable.
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* If it isn't found, send a custom error packet to the client.
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*/
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if ((target = (char*)hashtable_fetch(dbhash, (char*)db)) == NULL)
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{
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succp = false;
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goto retblock;
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}
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else
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{
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strcpy(dest, db);
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MXS_INFO("change_current_db: database is on server: '%s'.", target);
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succp = true;
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goto retblock;
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}
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}
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else
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{
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/** Create error message */
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MXS_ERROR("change_current_db: failed to change database: Query buffer too large");
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MXS_INFO("change_current_db: failed to change database: "
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"Query buffer too large [%ld bytes]", GWBUF_LENGTH(buf));
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succp = false;
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goto retblock;
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}
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retblock:
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return succp;
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}
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