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NetBSD/lib/librt/sem.c

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/* $NetBSD: sem.c,v 1.5 2008/11/14 15:49:20 ad Exp $ */
/*-
* Copyright (c) 2003 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: sem.c,v 1.5 2008/11/14 15:49:20 ad Exp $");
/*
* If an application is linked against both librt and libpthread, the
* libpthread versions must be used. Provide weak aliases to cause
* this behavior.
*/
#define sem_init _librt_sem_init
#define sem_destroy _librt_sem_destroy
#define sem_open _librt_sem_open
#define sem_close _librt_sem_close
#define sem_unlink _librt_sem_unlink
#define sem_wait _librt_sem_wait
#define sem_trywait _librt_sem_trywait
#define sem_post _librt_sem_post
#define sem_getvalue _librt_sem_getvalue
#define _LIBC
#include <sys/types.h>
#include <sys/ksem.h>
#include <sys/queue.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <semaphore.h>
#include <stdarg.h>
struct _sem_st {
unsigned int ksem_magic;
#define KSEM_MAGIC 0x90af0421U
LIST_ENTRY(_sem_st) ksem_list;
intptr_t ksem_semid; /* 0 -> user (non-shared) */
sem_t *ksem_identity;
};
static int sem_alloc(unsigned int value, intptr_t semid, sem_t *semp);
static void sem_free(sem_t sem);
static LIST_HEAD(, _sem_st) named_sems = LIST_HEAD_INITIALIZER(&named_sems);
#ifdef __weak_alias
__weak_alias(sem_init,_librt_sem_init)
__weak_alias(sem_destroy,_librt_sem_destroy)
__weak_alias(sem_open,_librt_sem_open)
__weak_alias(sem_close,_librt_sem_close)
__weak_alias(sem_unlink,_librt_sem_unlink)
__weak_alias(sem_wait,_librt_sem_wait)
__weak_alias(sem_trywait,_librt_sem_trywait)
__weak_alias(sem_post,_librt_sem_post)
__weak_alias(sem_getvalue,_librt_sem_getvalue)
#endif
static void
sem_free(sem_t sem)
{
sem->ksem_magic = 0;
free(sem);
}
static int
sem_alloc(unsigned int value, intptr_t semid, sem_t *semp)
{
sem_t sem;
if (value > SEM_VALUE_MAX)
return (EINVAL);
if ((sem = malloc(sizeof(struct _sem_st))) == NULL)
return (ENOSPC);
sem->ksem_magic = KSEM_MAGIC;
sem->ksem_semid = semid;
*semp = sem;
return (0);
}
/* ARGSUSED */
int
sem_init(sem_t *sem, int pshared, unsigned int value)
{
intptr_t semid;
int error;
if (_ksem_init(value, &semid) == -1)
return (-1);
if ((error = sem_alloc(value, semid, sem)) != 0) {
_ksem_destroy(semid);
errno = error;
return (-1);
}
return (0);
}
int
sem_destroy(sem_t *sem)
{
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
errno = EINVAL;
return (-1);
}
#endif
if (_ksem_destroy((*sem)->ksem_semid) == -1)
return (-1);
sem_free(*sem);
return (0);
}
sem_t *
sem_open(const char *name, int oflag, ...)
{
sem_t *sem, s;
intptr_t semid;
mode_t mode;
unsigned int value;
int error;
va_list ap;
mode = 0;
value = 0;
if (oflag & O_CREAT) {
va_start(ap, oflag);
mode = va_arg(ap, int);
value = va_arg(ap, unsigned int);
va_end(ap);
}
/*
* We can be lazy and let the kernel handle the oflag,
* we'll just merge duplicate IDs into our list.
*/
if (_ksem_open(name, oflag, mode, value, &semid) == -1)
return (SEM_FAILED);
/*
* Search for a duplicate ID, we must return the same sem_t *
* if we locate one.
*/
LIST_FOREACH(s, &named_sems, ksem_list) {
if (s->ksem_semid == semid)
return (s->ksem_identity);
}
if ((sem = malloc(sizeof(*sem))) == NULL) {
error = ENOSPC;
goto bad;
}
if ((error = sem_alloc(value, semid, sem)) != 0)
goto bad;
LIST_INSERT_HEAD(&named_sems, *sem, ksem_list);
(*sem)->ksem_identity = sem;
return (sem);
bad:
_ksem_close(semid);
if (sem != NULL) {
if (*sem != NULL)
sem_free(*sem);
free(sem);
}
errno = error;
return (SEM_FAILED);
}
int
sem_close(sem_t *sem)
{
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
errno = EINVAL;
return (-1);
}
#endif
if (_ksem_close((*sem)->ksem_semid) == -1)
return (-1);
LIST_REMOVE((*sem), ksem_list);
sem_free(*sem);
free(sem);
return (0);
}
int
sem_unlink(const char *name)
{
return (_ksem_unlink(name));
}
int
sem_wait(sem_t *sem)
{
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
errno = EINVAL;
return (-1);
}
#endif
return (_ksem_wait((*sem)->ksem_semid));
}
int
sem_trywait(sem_t *sem)
{
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
errno = EINVAL;
return (-1);
}
#endif
return (_ksem_trywait((*sem)->ksem_semid));
}
int
sem_post(sem_t *sem)
{
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
errno = EINVAL;
return (-1);
}
#endif
return (_ksem_post((*sem)->ksem_semid));
}
int
sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
{
#ifdef ERRORCHECK
if (sem == NULL || *sem == NULL || (*sem)->ksem_magic != KSEM_MAGIC) {
errno = EINVAL;
return (-1);
}
#endif
return (_ksem_getvalue((*sem)->ksem_semid, sval));
}
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