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96 lines
3.4 KiB
96 lines
3.4 KiB
/* Copyright (c) 2016, 2018, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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#include "sql/check_stack.h"
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#include "my_config.h"
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#include <stdio.h>
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#include <algorithm>
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#include <atomic>
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#include <new>
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#include "my_compiler.h"
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#include "my_dbug.h"
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#include "my_inttypes.h"
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#include "my_sys.h"
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#include "mysql_com.h"
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#include "mysqld_error.h"
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#include "sql/current_thd.h"
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#include "sql/derror.h"
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#include "sql/sql_class.h"
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/****************************************************************************
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Check stack size; Send error if there isn't enough stack to continue
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****************************************************************************/
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#if STACK_DIRECTION < 0
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#define used_stack(A, B) (long)(A - B)
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#else
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#define used_stack(A, B) (long)(B - A)
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#endif
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#ifndef DBUG_OFF
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std::atomic<long> max_stack_used;
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#endif
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/**
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Check stack for a overrun
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@param thd Thread handler.
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@param margin Minimal acceptable unused space in the stack.
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@param buf See a note below.
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@returns false if success, true if error (reported).
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@note
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Note: The 'buf' parameter is necessary, even if it is unused here.
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- fix_fields functions has a "dummy" buffer large enough for the
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corresponding exec. (Thus we only have to check in fix_fields.)
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- Passing to check_stack_overrun() prevents the compiler from removing it.
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*/
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bool check_stack_overrun(const THD *thd, long margin,
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unsigned char *buf MY_ATTRIBUTE((unused))) {
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DBUG_ASSERT(thd == current_thd);
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long stack_used =
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used_stack(thd->thread_stack, reinterpret_cast<char *>(&stack_used));
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if (stack_used >= static_cast<long>(my_thread_stack_size - margin) ||
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DBUG_EVALUATE_IF("simulate_stack_overrun", true, false)) {
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/*
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Do not use stack for the message buffer to ensure correct
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behaviour in cases we have close to no stack left.
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*/
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char *ebuff = new (std::nothrow) char[MYSQL_ERRMSG_SIZE];
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if (ebuff) {
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snprintf(ebuff, MYSQL_ERRMSG_SIZE,
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ER_THD(thd, ER_STACK_OVERRUN_NEED_MORE), stack_used,
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my_thread_stack_size, margin);
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my_message(ER_STACK_OVERRUN_NEED_MORE, ebuff, MYF(ME_FATALERROR));
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delete[] ebuff;
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}
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return true;
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}
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#ifndef DBUG_OFF
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max_stack_used = std::max(max_stack_used.load(), stack_used);
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#endif
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return false;
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}
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