glibc/nptl/pthread_barrier_wait.c
Joseph Myers 90dd591393 Fix mq_notify pthread_barrier_* namespace (bug 18544).
mq_notify (present in POSIX by 1996) brings in references to
pthread_barrier_init and pthread_barrier_wait (new in the 2001 edition
of POSIX).  This patch fixes this by making those functions into weak
aliases of __pthread_barrier_*, exporting the __pthread_barrier_*
names at version GLIBC_PRIVATE and using them in mq_notify.

Tested for x86_64 and x86 (testsuite, and comparison of installed
stripped shared libraries).  Changes in addresses from dynamic symbol
table / PLT changes render most comparisons not particularly useful,
but when the addresses of subsequent code don't change there's no sign
of unexpected changes there.  This patch does not remove any
linknamespace XFAILs because of other namespace issues remaining with
mqueue.h functions.

	[BZ #18544]
	* nptl/pthread_barrier_init.c (pthread_barrier_init): Rename to
	__pthread_barrier_init and define as weak alias of
	__pthread_barrier_init.
	* sysdeps/sparc/nptl/pthread_barrier_init.c
	(pthread_barrier_init): Likewise.
	* nptl/pthread_barrier_wait.c (pthread_barrier_wait): Rename to
	__pthread_barrier_wait and define as weak alias of
	__pthread_barrier_wait.
	* sysdeps/sparc/nptl/pthread_barrier_wait.c
	(pthread_barrier_wait): Likewise.
	* sysdeps/sparc/sparc32/pthread_barrier_wait.c
	(pthread_barrier_wait): Likewise.
	* sysdeps/unix/sysv/linux/i386/i486/pthread_barrier_wait.S
	(pthread_barrier_wait): Likewise.
	* sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S
	(pthread_barrier_wait): Likewise.
	* nptl/Versions (libpthread): Export __pthread_barrier_init and
	__pthread_barrier_wait at version GLIBC_PRIVATE.
	* include/pthread.h (__pthread_barrier_init): Declare.
	(__pthread_barrier_wait): Likewise.
	* sysdeps/unix/sysv/linux/mq_notify.c (notification_function):
	Call __pthread_barrier_wait instead of pthread_barrier_wait.
	(helper_thread): Likewise.
	(init_mq_netlink): Call __pthread_barrier_init instead of
	pthread_barrier_init.
2015-06-17 20:16:56 +00:00

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2.6 KiB
C

/* Copyright (C) 2003-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <pthreadP.h>
/* Wait on barrier. */
int
__pthread_barrier_wait (barrier)
pthread_barrier_t *barrier;
{
struct pthread_barrier *ibarrier = (struct pthread_barrier *) barrier;
int result = 0;
/* Make sure we are alone. */
lll_lock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
/* One more arrival. */
--ibarrier->left;
/* Are these all? */
if (ibarrier->left == 0)
{
/* Yes. Increment the event counter to avoid invalid wake-ups and
tell the current waiters that it is their turn. */
++ibarrier->curr_event;
/* Wake up everybody. */
lll_futex_wake (&ibarrier->curr_event, INT_MAX,
ibarrier->private ^ FUTEX_PRIVATE_FLAG);
/* This is the thread which finished the serialization. */
result = PTHREAD_BARRIER_SERIAL_THREAD;
}
else
{
/* The number of the event we are waiting for. The barrier's event
number must be bumped before we continue. */
unsigned int event = ibarrier->curr_event;
/* Before suspending, make the barrier available to others. */
lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
/* Wait for the event counter of the barrier to change. */
do
lll_futex_wait (&ibarrier->curr_event, event,
ibarrier->private ^ FUTEX_PRIVATE_FLAG);
while (event == ibarrier->curr_event);
}
/* Make sure the init_count is stored locally or in a register. */
unsigned int init_count = ibarrier->init_count;
/* If this was the last woken thread, unlock. */
if (atomic_increment_val (&ibarrier->left) == init_count)
/* We are done. */
lll_unlock (ibarrier->lock, ibarrier->private ^ FUTEX_PRIVATE_FLAG);
return result;
}
weak_alias (__pthread_barrier_wait, pthread_barrier_wait)