platform_bionic/libc/private/bionic_futex.h
Elliott Hughes 877ec6d904 Fix pthread_join.
Let the kernel keep pthread_internal_t::tid updated, including
across forks and for the main thread. This then lets us fix
pthread_join to only return after the thread has really exited.

Also fix the thread attributes of the main thread so we don't
unmap the main thread's stack (which is really owned by the
dynamic linker and contains things like environment variables),
which fixes crashes when joining with an exited main thread
and also fixes problems reported publicly with accessing environment
variables after the main thread exits (for which I've added a new
unit test).

In passing I also fixed a bug where if the clone(2) inside
pthread_create(3) fails, we'd unmap the child's stack and TLS (which
contains the mutex) and then try to unlock the mutex. Boom! It wasn't
until after I'd uploaded the fix for this that I came across a new
public bug reporting this exact failure.

Bug: 8206355
Bug: 11693195
Bug: https://code.google.com/p/android/issues/detail?id=57421
Bug: https://code.google.com/p/android/issues/detail?id=62392
Change-Id: I2af9cf6e8ae510a67256ad93cad891794ed0580b
2013-11-18 19:48:11 -08:00

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C

/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _BIONIC_FUTEX_H
#define _BIONIC_FUTEX_H
#include <linux/compiler.h> /* needed for __user in non-uapi futex.h */
#include <linux/futex.h>
#include <sys/cdefs.h>
__BEGIN_DECLS
extern int __futex_wait(volatile void *ftx, int val, const struct timespec *timeout);
extern int __futex_wake(volatile void *ftx, int count);
extern int __futex_syscall3(volatile void *ftx, int op, int val);
extern int __futex_syscall4(volatile void *ftx, int op, int val, const struct timespec *timeout);
#ifndef FUTEX_PRIVATE_FLAG
#define FUTEX_PRIVATE_FLAG 128
#endif
#ifndef FUTEX_WAIT_PRIVATE
#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT|FUTEX_PRIVATE_FLAG)
#endif
#ifndef FUTEX_WAKE_PRIVATE
#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE|FUTEX_PRIVATE_FLAG)
#endif
/* Like __futex_wait/wake, but take an additional 'pshared' argument.
* when non-0, this will use normal futexes. Otherwise, private futexes.
*/
extern int __futex_wake_ex(volatile void *ftx, int pshared, int val);
extern int __futex_wait_ex(volatile void *ftx, int pshared, int val, const struct timespec *timeout);
__END_DECLS
#endif /* _BIONIC_FUTEX_H */