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/* Copyright (C) 2003 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <endian.h>
#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <pthread.h>
#include <pthreadP.h>
#include <shlib-compat.h>
/* Cleanup handler, defined in pthread_cond_wait.c. */
extern void __condvar_cleanup (void *arg)
__attribute__ ((visibility ("hidden")));
struct _condvar_cleanup_buffer
{
int oldtype;
pthread_cond_t *cond;
pthread_mutex_t *mutex;
};
int
__pthread_cond_timedwait (cond, mutex, abstime)
pthread_cond_t *cond;
pthread_mutex_t *mutex;
const struct timespec *abstime;
{
struct _pthread_cleanup_buffer buffer;
struct _condvar_cleanup_buffer cbuffer;
int result = 0;
/* Catch invalid parameters. */
if (abstime->tv_nsec >= 1000000000)
return EINVAL;
/* Make sure we are along. */
lll_mutex_lock (cond->__data.__lock);
/* Now we can release the mutex. */
int err = __pthread_mutex_unlock_internal (mutex);
if (err)
{
lll_mutex_unlock (cond->__data.__lock);
return err;
}
/* We have one new user of the condvar. */
++cond->__data.__total_seq;
/* Prepare structure passed to cancellation handler. */
cbuffer.cond = cond;
cbuffer.mutex = mutex;
/* Before we block we enable cancellation. Therefore we have to
install a cancellation handler. */
__pthread_cleanup_push (&buffer, __condvar_cleanup, &cbuffer);
/* The current values of the wakeup counter. The "woken" counter
must exceed this value. */
unsigned long long int val;
unsigned long long int seq;
val = seq = cond->__data.__wakeup_seq;
/* The futex syscall operates on a 32-bit word. That is fine, we
just use the low 32 bits of the sequence counter. */
#if BYTE_ORDER == LITTLE_ENDIAN
int *futex = ((int *) (&cond->__data.__wakeup_seq));
#elif BYTE_ORDER == BIG_ENDIAN
int *futex = ((int *) (&cond->__data.__wakeup_seq)) + 1;
#else
# error "No valid byte order"
#endif
while (1)
{
struct timespec rt;
{
#ifdef __NR_clock_gettime
INTERNAL_SYSCALL_DECL (err);
int val = INTERNAL_SYSCALL (clock_gettime, err, 2,
cond->__data.__clock, &rt);
# ifndef __ASSUME_POSIX_TIMERS
if (__builtin_expect (INTERNAL_SYSCALL_ERROR_P (val, err), 0))
{
struct timeval tv;
(void) gettimeofday (&tv, NULL);
/* Convert the absolute timeout value to a relative timeout. */
rt.tv_sec = abstime->tv_sec - tv.tv_sec;
rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
}
else
# endif
{
/* Convert the absolute timeout value to a relative timeout. */
rt.tv_sec = abstime->tv_sec - rt.tv_sec;
rt.tv_nsec = abstime->tv_nsec - rt.tv_nsec;
}
#else
/* Get the current time. So far we support only one clock. */
struct timeval tv;
(void) gettimeofday (&tv, NULL);
/* Convert the absolute timeout value to a relative timeout. */
rt.tv_sec = abstime->tv_sec - tv.tv_sec;
rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
#endif
}
if (rt.tv_nsec < 0)
{
rt.tv_nsec += 1000000000;
--rt.tv_sec;
}
/* Did we already time out? */
if (rt.tv_sec < 0)
{
/* Yep. Adjust the sequence counter. */
++cond->__data.__wakeup_seq;
/* The error value. */
result = ETIMEDOUT;
break;
}
/* Prepare to wait. Release the condvar futex. */
lll_mutex_unlock (cond->__data.__lock);
/* Enable asynchronous cancellation. Required by the standard. */
__pthread_enable_asynccancel_2 (&cbuffer.oldtype);
/* Wait until woken by signal or broadcast. Note that we
truncate the 'val' value to 32 bits. */
err = lll_futex_timed_wait (futex, (unsigned int) val, &rt);
/* Disable asynchronous cancellation. */
__pthread_disable_asynccancel (cbuffer.oldtype);
/* We are going to look at shared data again, so get the lock. */
lll_mutex_lock(cond->__data.__lock);
/* Check whether we are eligible for wakeup. */
val = cond->__data.__wakeup_seq;
if (val > seq && cond->__data.__woken_seq < val)
break;
/* Not woken yet. Maybe the time expired? */
if (err == -ETIMEDOUT)
{
/* Yep. Adjust the counters. */
++cond->__data.__wakeup_seq;
/* The error value. */
result = ETIMEDOUT;
break;
}
}
/* Another thread woken up. */
++cond->__data.__woken_seq;
/* We are done with the condvar. */
lll_mutex_unlock (cond->__data.__lock);
/* The cancellation handling is back to normal, remove the handler. */
__pthread_cleanup_pop (&buffer, 0);
/* Get the mutex before returning. */
err = __pthread_mutex_lock_internal (mutex);
return err ?: result;
}
versioned_symbol (libpthread, __pthread_cond_timedwait, pthread_cond_timedwait,
GLIBC_2_3_2);
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