/usr/lib/erlang/erts-9.2/include/internal/pthread/ethr_event.h is in erlang-dev 1:20.2.2+dfsg-1ubuntu2.
This file is owned by root:root, with mode 0o644.
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* %CopyrightBegin%
*
* Copyright Ericsson AB 2009-2016. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* %CopyrightEnd%
*/
/*
* Author: Rickard Green
*/
#if defined(ETHR_HAVE_LINUX_FUTEX) && defined(ETHR_HAVE_32BIT_NATIVE_ATOMIC_OPS)
/* --- Linux futex implementation of ethread events ------------------------- */
#define ETHR_LINUX_FUTEX_IMPL__
#include <sys/syscall.h>
#include <unistd.h>
#include <linux/futex.h>
#include <sys/time.h>
#define ETHR_EVENT_OFF_WAITER__ ((ethr_sint32_t) -1)
#define ETHR_EVENT_OFF__ ((ethr_sint32_t) 1)
#define ETHR_EVENT_ON__ ((ethr_sint32_t) 0)
#if defined(FUTEX_WAIT_PRIVATE) && defined(FUTEX_WAKE_PRIVATE)
# define ETHR_FUTEX_WAIT__ FUTEX_WAIT_PRIVATE
# define ETHR_FUTEX_WAKE__ FUTEX_WAKE_PRIVATE
#else
# define ETHR_FUTEX_WAIT__ FUTEX_WAIT
# define ETHR_FUTEX_WAKE__ FUTEX_WAKE
#endif
typedef struct {
ethr_atomic32_t futex;
} ethr_event;
#define ETHR_FUTEX__(FTX, OP, VAL, TIMEOUT) \
(-1 == syscall(__NR_futex, \
(void *) ethr_atomic32_addr((FTX)), \
(OP), \
(int) (VAL), \
(TIMEOUT), \
NULL, \
0) \
? errno : 0)
#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_set)(ethr_event *e)
{
ethr_sint32_t val;
val = ethr_atomic32_xchg_mb(&e->futex, ETHR_EVENT_ON__);
if (val == ETHR_EVENT_OFF_WAITER__) {
int res = ETHR_FUTEX__(&e->futex, ETHR_FUTEX_WAKE__, 1, NULL);
if (res != 0)
ETHR_FATAL_ERROR__(res);
}
}
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_reset)(ethr_event *e)
{
ethr_atomic32_set(&e->futex, ETHR_EVENT_OFF__);
ETHR_MEMORY_BARRIER;
}
#endif
#elif defined(ETHR_PTHREADS)
/* --- Posix mutex/cond pipe/select implementation of events ---------------- */
#if defined(__APPLE__) && defined(__MACH__) && !defined(__DARWIN__)
# define __DARWIN__ 1
#endif
#ifdef __DARWIN__
typedef struct ethr_event_fdsets___ ethr_event_fdsets__;
#endif
typedef struct {
ethr_atomic32_t state;
pthread_mutex_t mtx;
pthread_cond_t cnd;
int fd[2];
#ifdef __DARWIN__
ethr_event_fdsets__ *fdsets;
#endif
} ethr_event;
#define ETHR_EVENT_OFF_WAITER_SELECT__ ((ethr_sint32_t) -2)
#define ETHR_EVENT_OFF_WAITER__ ((ethr_sint32_t) -1)
#define ETHR_EVENT_OFF__ ((ethr_sint32_t) 1)
#define ETHR_EVENT_ON__ ((ethr_sint32_t) 0)
#define ETHR_EVENT_IS_WAITING__(VAL) ((VAL) < 0)
#if defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
#ifndef ETHR_HAVE_PTHREAD_TIMED_COND_MONOTONIC
#include <unistd.h>
#include <errno.h>
#endif
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_set)(ethr_event *e)
{
ethr_sint32_t val;
val = ethr_atomic32_xchg_mb(&e->state, ETHR_EVENT_ON__);
if (ETHR_EVENT_IS_WAITING__(val)) {
int res;
if (val == ETHR_EVENT_OFF_WAITER_SELECT__) {
ssize_t wres;
int fd = e->fd[1];
ETHR_ASSERT(fd >= 0);
do {
wres = write(fd, "!", 1);
} while (wres < 0 && errno == EINTR);
if (wres < 0 && errno != EAGAIN && errno != EWOULDBLOCK)
ETHR_FATAL_ERROR__(errno);
}
else {
res = pthread_mutex_lock(&e->mtx);
if (res != 0)
ETHR_FATAL_ERROR__(res);
res = pthread_cond_signal(&e->cnd);
if (res != 0)
ETHR_FATAL_ERROR__(res);
res = pthread_mutex_unlock(&e->mtx);
if (res != 0)
ETHR_FATAL_ERROR__(res);
}
}
}
static void ETHR_INLINE
ETHR_INLINE_FUNC_NAME_(ethr_event_reset)(ethr_event *e)
{
ethr_atomic32_set(&e->state, ETHR_EVENT_OFF__);
ETHR_MEMORY_BARRIER;
}
#endif
#endif
int ethr_event_init(ethr_event *e);
int ethr_event_prepare_timed(ethr_event *e);
int ethr_event_destroy(ethr_event *e);
int ethr_event_wait(ethr_event *e);
int ethr_event_swait(ethr_event *e, int spincount);
int ethr_event_twait(ethr_event *e, ethr_sint64_t timeout);
int ethr_event_stwait(ethr_event *e, int spincount, ethr_sint64_t timeout);
#if !defined(ETHR_TRY_INLINE_FUNCS) || defined(ETHR_EVENT_IMPL__)
void ethr_event_set(ethr_event *e);
void ethr_event_reset(ethr_event *e);
#endif
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