e0554a531f
Only warnings that could be fixed without changing the generated object code and without restructuring the source code have been handled. Reviewed by: /sbin/md5
358 lines
7.1 KiB
C
358 lines
7.1 KiB
C
/*
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* Copyright (C) 2000 Jason Evans <jasone@freebsd.org>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice(s), this list of conditions and the following disclaimer as
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* the first lines of this file unmodified other than the possible
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* addition of one or more copyright notices.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice(s), this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include "namespace.h"
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#include <stdlib.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <semaphore.h>
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#include <stdarg.h>
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#include <pthread.h>
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#include <sys/queue.h>
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#include <_semaphore.h>
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#include "un-namespace.h"
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#define _SEM_CHECK_VALIDITY(sem) \
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if ((*(sem))->magic != SEM_MAGIC) { \
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errno = EINVAL; \
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retval = -1; \
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goto RETURN; \
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}
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static sem_t sem_alloc(unsigned int value, semid_t semid, int system_sem);
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static void sem_free(sem_t sem);
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static LIST_HEAD(, sem) named_sems = LIST_HEAD_INITIALIZER(&named_sems);
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static pthread_mutex_t named_sems_mtx = PTHREAD_MUTEX_INITIALIZER;
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static void
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sem_free(sem_t sem)
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{
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_pthread_mutex_destroy(&sem->lock);
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_pthread_cond_destroy(&sem->gtzero);
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sem->magic = 0;
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free(sem);
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}
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static sem_t
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sem_alloc(unsigned int value, semid_t semid, int system_sem)
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{
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sem_t sem;
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if (value > SEM_VALUE_MAX) {
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errno = EINVAL;
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return (NULL);
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}
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sem = (sem_t)malloc(sizeof(struct sem));
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if (sem == NULL) {
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errno = ENOSPC;
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return (NULL);
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}
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/*
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* Initialize the semaphore.
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*/
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if (_pthread_mutex_init(&sem->lock, NULL) != 0) {
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free(sem);
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errno = ENOSPC;
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return (NULL);
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}
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if (_pthread_cond_init(&sem->gtzero, NULL) != 0) {
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_pthread_mutex_destroy(&sem->lock);
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free(sem);
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errno = ENOSPC;
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return (NULL);
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}
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sem->count = (u_int32_t)value;
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sem->nwaiters = 0;
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sem->magic = SEM_MAGIC;
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sem->semid = semid;
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sem->syssem = system_sem;
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return (sem);
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}
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int
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sem_init(sem_t *sem, int pshared, unsigned int value)
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{
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int retval, got_system_sem;
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semid_t semid;
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got_system_sem = 0;
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semid = SEM_USER;
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/*
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* Range check the arguments.
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*/
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if (pshared != 0) {
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retval = ksem_init(&semid, value);
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if (retval == -1)
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goto RETURN;
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got_system_sem = 1;
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}
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(*sem) = sem_alloc(value, semid, got_system_sem);
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if ((*sem) == NULL)
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retval = -1;
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else
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retval = 0;
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RETURN:
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if (retval != 0 && got_system_sem)
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ksem_destroy(semid);
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return retval;
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}
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int
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sem_destroy(sem_t *sem)
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{
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int retval;
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_SEM_CHECK_VALIDITY(sem);
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_pthread_mutex_lock(&(*sem)->lock);
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/*
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* If this is a system semaphore let the kernel track it otherwise
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* make sure there are no waiters.
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*/
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if ((*sem)->syssem != 0) {
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retval = ksem_destroy((*sem)->semid);
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if (retval == -1) {
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_pthread_mutex_unlock(&(*sem)->lock);
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goto RETURN;
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}
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} else if ((*sem)->nwaiters > 0) {
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_pthread_mutex_unlock(&(*sem)->lock);
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errno = EBUSY;
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retval = -1;
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goto RETURN;
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}
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_pthread_mutex_unlock(&(*sem)->lock);
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sem_free(*sem);
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retval = 0;
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RETURN:
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return retval;
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}
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sem_t *
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sem_open(const char *name, int oflag, ...)
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{
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sem_t *sem;
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sem_t s;
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semid_t semid;
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mode_t mode;
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unsigned int value;
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mode = 0;
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value = 0;
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if ((oflag & O_CREAT) != 0) {
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va_list ap;
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va_start(ap, oflag);
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mode = va_arg(ap, int);
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value = va_arg(ap, unsigned int);
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va_end(ap);
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}
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/*
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* we can be lazy and let the kernel handle the "oflag",
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* we'll just merge duplicate IDs into our list.
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*/
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if (ksem_open(&semid, name, oflag, mode, value) == -1)
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return (SEM_FAILED);
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/*
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* search for a duplicate ID, we must return the same sem_t *
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* if we locate one.
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*/
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_pthread_mutex_lock(&named_sems_mtx);
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LIST_FOREACH(s, &named_sems, entry) {
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if (s->semid == semid) {
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_pthread_mutex_unlock(&named_sems_mtx);
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return (s->backpointer);
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}
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}
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sem = (sem_t *)malloc(sizeof(*sem));
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if (sem == NULL)
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goto err;
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*sem = sem_alloc(value, semid, 1);
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if ((*sem) == NULL)
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goto err;
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LIST_INSERT_HEAD(&named_sems, *sem, entry);
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(*sem)->backpointer = sem;
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_pthread_mutex_unlock(&named_sems_mtx);
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return (sem);
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err:
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_pthread_mutex_unlock(&named_sems_mtx);
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ksem_close(semid);
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if (sem != NULL) {
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if (*sem != NULL)
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sem_free(*sem);
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else
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errno = ENOSPC;
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free(sem);
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} else {
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errno = ENOSPC;
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}
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return (SEM_FAILED);
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}
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int
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sem_close(sem_t *sem)
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{
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if ((*sem)->syssem == 0) {
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errno = EINVAL;
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return (-1);
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}
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_pthread_mutex_lock(&named_sems_mtx);
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if (ksem_close((*sem)->semid) == -1) {
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_pthread_mutex_unlock(&named_sems_mtx);
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return (-1);
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}
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LIST_REMOVE((*sem), entry);
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_pthread_mutex_unlock(&named_sems_mtx);
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sem_free(*sem);
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free(sem);
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return (0);
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}
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int
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sem_unlink(const char *name)
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{
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return (ksem_unlink(name));
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}
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int
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sem_wait(sem_t *sem)
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{
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int retval;
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_SEM_CHECK_VALIDITY(sem);
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if ((*sem)->syssem != 0) {
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retval = ksem_wait((*sem)->semid);
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goto RETURN;
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}
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_pthread_mutex_lock(&(*sem)->lock);
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while ((*sem)->count == 0) {
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(*sem)->nwaiters++;
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_pthread_cond_wait(&(*sem)->gtzero, &(*sem)->lock);
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(*sem)->nwaiters--;
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}
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(*sem)->count--;
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_pthread_mutex_unlock(&(*sem)->lock);
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retval = 0;
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RETURN:
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return retval;
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}
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int
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sem_trywait(sem_t *sem)
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{
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int retval;
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_SEM_CHECK_VALIDITY(sem);
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if ((*sem)->syssem != 0) {
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retval = ksem_trywait((*sem)->semid);
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goto RETURN;
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}
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_pthread_mutex_lock(&(*sem)->lock);
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if ((*sem)->count > 0) {
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(*sem)->count--;
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retval = 0;
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} else {
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errno = EAGAIN;
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retval = -1;
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}
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_pthread_mutex_unlock(&(*sem)->lock);
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RETURN:
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return retval;
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}
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int
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sem_post(sem_t *sem)
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{
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int retval;
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_SEM_CHECK_VALIDITY(sem);
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if ((*sem)->syssem != 0) {
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retval = ksem_post((*sem)->semid);
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goto RETURN;
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}
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_pthread_mutex_lock(&(*sem)->lock);
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(*sem)->count++;
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if ((*sem)->nwaiters > 0)
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_pthread_cond_signal(&(*sem)->gtzero);
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_pthread_mutex_unlock(&(*sem)->lock);
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retval = 0;
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RETURN:
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return retval;
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}
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int
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sem_getvalue(sem_t * __restrict sem, int * __restrict sval)
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{
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int retval;
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_SEM_CHECK_VALIDITY(sem);
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if ((*sem)->syssem != 0) {
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retval = ksem_getvalue((*sem)->semid, sval);
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goto RETURN;
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}
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_pthread_mutex_lock(&(*sem)->lock);
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*sval = (int)(*sem)->count;
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_pthread_mutex_unlock(&(*sem)->lock);
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retval = 0;
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RETURN:
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return retval;
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}
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