[thirdparty/glibc.git] / sysdeps / nacl / lowlevellock-futex.h

/* Low-level locking access to futex facilities.  NaCl version.
   Copyright (C) 2015-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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/>.  */

#ifndef _LOWLEVELLOCK_FUTEX_H
#define _LOWLEVELLOCK_FUTEX_H   1

#include <nacl-interfaces.h>
#include <time.h>


#pragma GCC diagnostic ignored "-Wunused-value" /* XXX */

/* Values for 'private' parameter of locking macros.  Note pthreadP.h
   optimizes for these exact values, though they are not required.  */
#define LLL_PRIVATE     0
#define LLL_SHARED      128

#define FUTEX_PRIVATE_FLAG	0       /* XXX */


/* Wait while *FUTEXP == VAL for an lll_futex_wake call on FUTEXP.  */
#define lll_futex_wait(futexp, val, private) \
  ((void) (private), \
   - __nacl_irt_futex.futex_wait_abs ((volatile int *) (futexp), val, NULL))

/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses.  */
#define lll_futex_timed_wait(futexp, val, timeout, private)             \
  ({                                                                    \
    /* This timeout is relative, but the IRT call wants it absolute.  */\
    const struct timespec *_to = (timeout);                             \
    struct timespec _ts;                                                \
    int _err = 0;                                                       \
    if (_to != NULL                                                     \
	&& __glibc_likely ((_err = __nacl_irt_clock.clock_gettime	\
			    (CLOCK_REALTIME, &_ts)) == 0))		\
      {                                                                 \
	_ts.tv_sec += _to->tv_sec;                                      \
	_ts.tv_nsec += _to->tv_nsec;                                    \
	while (_ts.tv_nsec >= 1000000000)                               \
	  {                                                             \
	    _ts.tv_nsec -= 1000000000;                                  \
	    ++_ts.tv_sec;                                               \
	  }                                                             \
	_to = &_ts;                                                     \
      }                                                                 \
    if (_err == 0)                                                      \
      _err = __nacl_irt_futex.futex_wait_abs				\
	((volatile int *) (futexp), val, _to);                          \
    (void) (private);							\
    -_err;								\
  })

/* Wake up up to NR waiters on FUTEXP.  */
#define lll_futex_wake(futexp, nr, private)                     \
  ({                                                            \
    int _woken;                                                 \
    (void) (private);						\
    - __nacl_irt_futex.futex_wake ((volatile int *) (futexp), nr, &_woken); \
  })

/* NaCl does not support the requeue operation.  The only use of this is in
   pthread_cond_broadcast, which handles an error return by falling back to
   plain lll_futex_wake.  */
#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
  ((futexp), (nr_wake), (nr_move), (mutex), (val), (private), -ENOSYS)

/* NaCl does not support the special wake-unlock operation.  The only use
   of this is in pthread_cond_signal, which handles an error return by
   falling back to plain lll_futex_wake.  */
/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2.  */
#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
  ((futexp), (nr_wake), (nr_wake2), (futexp2), (private), -ENOSYS)


#endif  /* lowlevellock-futex.h */
Commit	Line	Data
d1e44df1	1	/* Low-level locking access to futex facilities. NaCl version.
bfff8b1b	2	Copyright (C) 2015-2017 Free Software Foundation, Inc.
d1e44df1 RM	3	This file is part of the GNU C Library.
	4
	5	The GNU C Library is free software; you can redistribute it and/or
	6	modify it under the terms of the GNU Lesser General Public
	7	License as published by the Free Software Foundation; either
	8	version 2.1 of the License, or (at your option) any later version.
	9
	10	The GNU C Library is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	Lesser General Public License for more details.
	14
	15	You should have received a copy of the GNU Lesser General Public
	16	License along with the GNU C Library. If not, see
	17	<http://www.gnu.org/licenses/>. */
	18
	19	#ifndef _LOWLEVELLOCK_FUTEX_H
	20	#define _LOWLEVELLOCK_FUTEX_H 1
	21
	22	#include <nacl-interfaces.h>
	23	#include <time.h>
	24
	25
	26	#pragma GCC diagnostic ignored "-Wunused-value" /* XXX */
	27
	28	/* Values for 'private' parameter of locking macros. Note pthreadP.h
	29	optimizes for these exact values, though they are not required. */
	30	#define LLL_PRIVATE 0
	31	#define LLL_SHARED 128
	32
	33	#define FUTEX_PRIVATE_FLAG 0 /* XXX */
	34
	35
	36	/* Wait while FUTEXP == VAL for an lll_futex_wake call on FUTEXP. /
	37	#define lll_futex_wait(futexp, val, private) \
a3140836 RM	38	((void) (private), \
a3140836 RM	39	- __nacl_irt_futex.futex_wait_abs ((volatile int *) (futexp), val, NULL))
d1e44df1 RM	40
	41	/* Wait until a lll_futex_wake call on FUTEXP, or TIMEOUT elapses. */
	42	#define lll_futex_timed_wait(futexp, val, timeout, private) \
	43	({ \
f2175470	44	/* This timeout is relative, but the IRT call wants it absolute. */\
d1e44df1 RM	45	const struct timespec *_to = (timeout); \
	46	struct timespec _ts; \
	47	int _err = 0; \
	48	if (_to != NULL \
f2175470 RM	49	&& __glibc_likely ((_err = __nacl_irt_clock.clock_gettime \
f2175470 RM	50	(CLOCK_REALTIME, &_ts)) == 0)) \
d1e44df1	51	{ \
f2175470 RM	52	_ts.tv_sec += _to->tv_sec; \
	53	_ts.tv_nsec += _to->tv_nsec; \
	54	while (_ts.tv_nsec >= 1000000000) \
	55	{ \
	56	_ts.tv_nsec -= 1000000000; \
	57	++_ts.tv_sec; \
	58	} \
	59	_to = &_ts; \
d1e44df1 RM	60	} \
	61	if (_err == 0) \
	62	_err = __nacl_irt_futex.futex_wait_abs \
f2175470	63	((volatile int *) (futexp), val, _to); \
a3140836 RM	64	(void) (private); \
a3140836 RM	65	-_err; \
d1e44df1 RM	66	})
	67
	68	/* Wake up up to NR waiters on FUTEXP. */
	69	#define lll_futex_wake(futexp, nr, private) \
	70	({ \
	71	int _woken; \
a3140836	72	(void) (private); \
d1e44df1 RM	73	- __nacl_irt_futex.futex_wake ((volatile int *) (futexp), nr, &_woken); \
	74	})
	75
	76	/* NaCl does not support the requeue operation. The only use of this is in
	77	pthread_cond_broadcast, which handles an error return by falling back to
	78	plain lll_futex_wake. */
	79	#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
	80	((futexp), (nr_wake), (nr_move), (mutex), (val), (private), -ENOSYS)
	81
	82	/* NaCl does not support the special wake-unlock operation. The only use
	83	of this is in pthread_cond_signal, which handles an error return by
	84	falling back to plain lll_futex_wake. */
	85	/* Wake up up to NR_WAKE waiters on FUTEXP and NR_WAKE2 on FUTEXP2. */
	86	#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
	87	((futexp), (nr_wake), (nr_wake2), (futexp2), (private), -ENOSYS)
	88
	89
	90	#endif /* lowlevellock-futex.h */