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/*
* Copyright (c) 2006-2008 Amit Singh/Google Inc.
* Copyright (c) 2012 Anatol Pomozov
* Copyright (c) 2011-2012 Benjamin Fleischer
*/
#include "darwin_compat.h"
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
/*
* Semaphore implementation based on:
*
* Copyright (C) 2000,02 Free Software Foundation, Inc.
* This file is part of the GNU C Library.
* Written by Ga<EB>l Le Mignot <address@hidden>
*
* The GNU C Library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with the GNU C Library; see the file COPYING.LIB. If not,
* write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/* Semaphores */
#define __SEM_ID_NONE ((int)0x0)
#define __SEM_ID_LOCAL ((int)0xcafef00d)
/* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_init.html */
int
darwin_sem_init(darwin_sem_t *sem, int pshared, unsigned int value)
{
if (pshared) {
errno = ENOSYS;
return -1;
}
sem->id = __SEM_ID_NONE;
if (pthread_cond_init(&sem->__data.local.count_cond, NULL)) {
goto cond_init_fail;
}
if (pthread_mutex_init(&sem->__data.local.count_lock, NULL)) {
goto mutex_init_fail;
}
sem->__data.local.count = value;
sem->id = __SEM_ID_LOCAL;
return 0;
mutex_init_fail:
pthread_cond_destroy(&sem->__data.local.count_cond);
cond_init_fail:
return -1;
}
/* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_destroy.html */
int
darwin_sem_destroy(darwin_sem_t *sem)
{
int res = 0;
pthread_mutex_lock(&sem->__data.local.count_lock);
sem->id = __SEM_ID_NONE;
pthread_cond_broadcast(&sem->__data.local.count_cond);
if (pthread_cond_destroy(&sem->__data.local.count_cond)) {
res = -1;
}
pthread_mutex_unlock(&sem->__data.local.count_lock);
if (pthread_mutex_destroy(&sem->__data.local.count_lock)) {
res = -1;
}
return res;
}
int
darwin_sem_getvalue(darwin_sem_t *sem, unsigned int *sval)
{
int res = 0;
pthread_mutex_lock(&sem->__data.local.count_lock);
if (sem->id != __SEM_ID_LOCAL) {
res = -1;
errno = EINVAL;
} else {
*sval = sem->__data.local.count;
}
pthread_mutex_unlock(&sem->__data.local.count_lock);
return res;
}
/* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_post.html */
int
darwin_sem_post(darwin_sem_t *sem)
{
int res = 0;
pthread_mutex_lock(&sem->__data.local.count_lock);
if (sem->id != __SEM_ID_LOCAL) {
res = -1;
errno = EINVAL;
} else if (sem->__data.local.count < DARWIN_SEM_VALUE_MAX) {
sem->__data.local.count++;
if (sem->__data.local.count == 1) {
pthread_cond_signal(&sem->__data.local.count_cond);
}
} else {
errno = ERANGE;
res = -1;
}
pthread_mutex_unlock(&sem->__data.local.count_lock);
return res;
}
/* http://www.opengroup.org/onlinepubs/009695399/functions/sem_timedwait.html */
int
darwin_sem_timedwait(darwin_sem_t *sem, const struct timespec *abs_timeout)
{
int res = 0;
if (abs_timeout &&
(abs_timeout->tv_nsec < 0 || abs_timeout->tv_nsec >= 1000000000)) {
errno = EINVAL;
return -1;
}
pthread_cleanup_push((void(*)(void*))&pthread_mutex_unlock,
&sem->__data.local.count_lock);
pthread_mutex_lock(&sem->__data.local.count_lock);
if (sem->id != __SEM_ID_LOCAL) {
errno = EINVAL;
res = -1;
} else {
if (!sem->__data.local.count) {
res = pthread_cond_timedwait(&sem->__data.local.count_cond,
&sem->__data.local.count_lock,
abs_timeout);
}
if (res) {
assert(res == ETIMEDOUT);
res = -1;
errno = ETIMEDOUT;
} else if (sem->id != __SEM_ID_LOCAL) {
res = -1;
errno = EINVAL;
} else {
sem->__data.local.count--;
}
}
pthread_cleanup_pop(1);
return res;
}
/* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_trywait.html */
int
darwin_sem_trywait(darwin_sem_t *sem)
{
int res = 0;
pthread_mutex_lock(&sem->__data.local.count_lock);
if (sem->id != __SEM_ID_LOCAL) {
res = -1;
errno = EINVAL;
} else if (sem->__data.local.count) {
sem->__data.local.count--;
} else {
res = -1;
errno = EAGAIN;
}
pthread_mutex_unlock (&sem->__data.local.count_lock);
return res;
}
/* http://www.opengroup.org/onlinepubs/007908799/xsh/sem_wait.html */
int
darwin_sem_wait(darwin_sem_t *sem)
{
int res = 0;
pthread_cleanup_push((void(*)(void*))&pthread_mutex_unlock,
&sem->__data.local.count_lock);
pthread_mutex_lock(&sem->__data.local.count_lock);
if (sem->id != __SEM_ID_LOCAL) {
errno = EINVAL;
res = -1;
} else {
if (!sem->__data.local.count) {
pthread_cond_wait(&sem->__data.local.count_cond,
&sem->__data.local.count_lock);
if (!sem->__data.local.count) {
/* spurious wakeup, assume it is an interruption */
res = -1;
errno = EINTR;
goto out;
}
}
if (sem->id != __SEM_ID_LOCAL) {
res = -1;
errno = EINVAL;
} else {
sem->__data.local.count--;
}
}
out:
pthread_cleanup_pop(1);
return res;
}
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