mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-03 20:53:13 +03:00
134 lines
3.7 KiB
C
134 lines
3.7 KiB
C
/* Copyright (C) 2006-2014 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Jakub Jelinek <jakub@redhat.com>, 2006.
|
|
|
|
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 <sys/time.h>
|
|
#include <pthreadP.h>
|
|
#include <kernel-features.h>
|
|
|
|
|
|
int
|
|
__lll_robust_lock_wait (int *futex, int private)
|
|
{
|
|
int oldval = *futex;
|
|
int tid = THREAD_GETMEM (THREAD_SELF, tid);
|
|
|
|
/* If the futex changed meanwhile try locking again. */
|
|
if (oldval == 0)
|
|
goto try;
|
|
|
|
do
|
|
{
|
|
/* If the owner died, return the present value of the futex. */
|
|
if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
|
|
return oldval;
|
|
|
|
/* Try to put the lock into state 'acquired, possibly with waiters'. */
|
|
int newval = oldval | FUTEX_WAITERS;
|
|
if (oldval != newval
|
|
&& atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
|
|
continue;
|
|
|
|
/* If *futex == 2, wait until woken. */
|
|
lll_futex_wait (futex, newval, private);
|
|
|
|
try:
|
|
;
|
|
}
|
|
while ((oldval = atomic_compare_and_exchange_val_acq (futex,
|
|
tid | FUTEX_WAITERS,
|
|
0)) != 0);
|
|
return 0;
|
|
}
|
|
|
|
|
|
int
|
|
__lll_robust_timedlock_wait (int *futex, const struct timespec *abstime,
|
|
int private)
|
|
{
|
|
/* Reject invalid timeouts. */
|
|
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
|
|
return EINVAL;
|
|
|
|
int tid = THREAD_GETMEM (THREAD_SELF, tid);
|
|
int oldval = *futex;
|
|
|
|
/* If the futex changed meanwhile, try locking again. */
|
|
if (oldval == 0)
|
|
goto try;
|
|
|
|
/* Work around the fact that the kernel rejects negative timeout values
|
|
despite them being valid. */
|
|
if (__glibc_unlikely (abstime->tv_sec < 0))
|
|
return ETIMEDOUT;
|
|
|
|
do
|
|
{
|
|
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|
|
|| !defined lll_futex_timed_wait_bitset)
|
|
struct timeval tv;
|
|
struct timespec rt;
|
|
|
|
/* Get the current time. */
|
|
(void) __gettimeofday (&tv, NULL);
|
|
|
|
/* Compute relative timeout. */
|
|
rt.tv_sec = abstime->tv_sec - tv.tv_sec;
|
|
rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
|
|
if (rt.tv_nsec < 0)
|
|
{
|
|
rt.tv_nsec += 1000000000;
|
|
--rt.tv_sec;
|
|
}
|
|
|
|
/* Already timed out? */
|
|
if (rt.tv_sec < 0)
|
|
return ETIMEDOUT;
|
|
#endif
|
|
|
|
/* If the owner died, return the present value of the futex. */
|
|
if (__glibc_unlikely (oldval & FUTEX_OWNER_DIED))
|
|
return oldval;
|
|
|
|
/* Try to put the lock into state 'acquired, possibly with waiters'. */
|
|
int newval = oldval | FUTEX_WAITERS;
|
|
if (oldval != newval
|
|
&& atomic_compare_and_exchange_bool_acq (futex, newval, oldval))
|
|
continue;
|
|
|
|
/* If *futex == 2, wait until woken or timeout. */
|
|
#if (!defined __ASSUME_FUTEX_CLOCK_REALTIME \
|
|
|| !defined lll_futex_timed_wait_bitset)
|
|
lll_futex_timed_wait (futex, newval, &rt, private);
|
|
#else
|
|
lll_futex_timed_wait_bitset (futex, newval, abstime,
|
|
FUTEX_CLOCK_REALTIME, private);
|
|
#endif
|
|
|
|
try:
|
|
;
|
|
}
|
|
while ((oldval = atomic_compare_and_exchange_val_acq (futex,
|
|
tid | FUTEX_WAITERS,
|
|
0)) != 0);
|
|
|
|
return 0;
|
|
}
|