76144aaa63
It is reported by tsan that funlockfile() can unlock an unlocked mutex. It happens when printf() is called before fopen() or other stdio stuff. As FLOCKFILE(fp) is called before __sinit(), _stdio_handles_locking is false, and _FLOCK(fp) will not be locked. But then cantwrite(fp) in __vfprintf() calls__sinit(), which makes _stdio_handles_locking become true, and FUNLOCKFILE(fp) unlocks _FLOCK(fp). Change _stdio_handles_locking into _caller_handles_locking, so __sinit() won't change its value. Add test due to my previous fault. Bug: 25392375 Change-Id: I483e3c3cdb28da65e62f1fd9615bf58c5403b4dd
70 lines
2.2 KiB
C++
70 lines
2.2 KiB
C++
/*
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* Copyright (C) 2008 The Android Open Source Project
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <errno.h>
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#include <stdio.h>
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#include "local.h"
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// We can't use the OpenBSD implementation which uses kernel-specific
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// APIs not available on Linux. Instead we use a pthread_mutex_t within
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// struct __sfileext (see fileext.h).
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void flockfile(FILE* fp) {
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if (!__sdidinit) {
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__sinit();
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}
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if (fp != nullptr) {
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pthread_mutex_lock(&_FLOCK(fp));
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}
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}
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int ftrylockfile(FILE* fp) {
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if (!__sdidinit) {
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__sinit();
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}
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// The specification for ftrylockfile() says it returns 0 on success,
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// or non-zero on error. So return an errno code directly on error.
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if (fp == nullptr) {
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return EINVAL;
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}
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return pthread_mutex_trylock(&_FLOCK(fp));
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}
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void funlockfile(FILE* fp) {
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if (!__sdidinit) {
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__sinit();
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}
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if (fp != nullptr) {
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pthread_mutex_unlock(&_FLOCK(fp));
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}
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}
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