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/*
* Copyright (C) 2010 Red Hat, Inc.
*
* Author: Angus Salkeld <asalkeld@redhat.com>
*
* This file is part of libqb.
*
* libqb 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.
*
* libqb 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 libqb. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _RINGBUFFER_H_
#define _RINGBUFFER_H_
#include "os_base.h"
#ifdef HAVE_SYS_MMAN_H
#include <sys/mman.h>
#endif /* HAVE_SYS_MMAN_H */
#ifdef HAVE_SYS_SEM_H
#include <sys/sem.h>
#endif
#ifdef HAVE_SYS_IPC_H
#include <sys/ipc.h>
#endif
#include "rpl_sem.h"
#include "util_int.h"
#include <qb/qbatomic.h>
#include <qb/qbutil.h>
#include <qb/qbrb.h>
struct qb_ringbuffer_s;
int32_t qb_rb_sem_create(struct qb_ringbuffer_s *rb, uint32_t flags);
typedef int32_t(*qb_rb_notifier_post_fn_t) (void * instance, size_t msg_size);
typedef ssize_t(*qb_rb_notifier_q_len_fn_t) (void * instance);
typedef ssize_t(*qb_rb_notifier_used_fn_t) (void * instance);
typedef int32_t(*qb_rb_notifier_timedwait_fn_t) (void * instance,
int32_t ms_timeout);
typedef int32_t(*qb_rb_notifier_reclaim_fn_t) (void * instance, size_t msg_size);
typedef int32_t(*qb_rb_notifier_destroy_fn_t) (void * instance);
struct qb_rb_notifier {
qb_rb_notifier_post_fn_t post_fn;
qb_rb_notifier_q_len_fn_t q_len_fn;
qb_rb_notifier_used_fn_t space_used_fn;
qb_rb_notifier_timedwait_fn_t timedwait_fn;
qb_rb_notifier_reclaim_fn_t reclaim_fn;
qb_rb_notifier_destroy_fn_t destroy_fn;
void *instance;
};
struct qb_ringbuffer_shared_s {
volatile uint32_t write_pt;
volatile uint32_t read_pt;
uint32_t word_size;
char hdr_path[PATH_MAX];
char data_path[PATH_MAX];
int32_t ref_count;
rpl_sem_t posix_sem;
char user_data[1];
} __attribute__ ((aligned(8)));
struct qb_ringbuffer_s {
uint32_t flags;
int32_t sem_id;
struct qb_ringbuffer_shared_s *shared_hdr;
uint32_t *shared_data;
struct qb_rb_notifier notifier;
};
void qb_rb_force_close(qb_ringbuffer_t * rb);
/**
* Helper to munmap, and conditionally unlink the file or possibly truncate it.
* @param rb ringbuffer instance.
* @param unlink_it whether the underlying files should be unlinked.
* @param truncate_fallback whether to truncate the files when unlink fails.
* @return 0 (success) or -errno
*/
int32_t qb_rb_close_helper(struct qb_ringbuffer_s * rb, int32_t unlink_it,
int32_t truncate_fallback);
qb_ringbuffer_t *qb_rb_open_2(const char *name, size_t size, uint32_t flags,
size_t shared_user_data_size,
struct qb_rb_notifier *notifier);
#ifndef HAVE_SEMUN
union semun {
int32_t val;
struct semid_ds *buf;
unsigned short int *array;
struct seminfo *__buf;
};
#endif /* HAVE_SEMUN */
/* This function is to be used to "decorate" argument (with an extra
reference level added) to qb_rb_{force_,}_close() so as to avoid trivial
IPC API misuses such as recv-after-close rather than avoiding races in
multi-threaded applications (although it partially helps there, too);
it's debatable whether that should be fixed at higher level in ipc[cs].c */
static inline struct qb_ringbuffer_s *
qb_rb_lastref_and_ret(struct qb_ringbuffer_s ** rb)
{
struct qb_ringbuffer_s *rb_res = *rb;
if (rb_res == NULL) {
return NULL;
}
*rb = NULL;
/* qb_rb_close will get rid of this "last reference" */
qb_atomic_int_set(&rb_res->shared_hdr->ref_count, 1);
return rb_res;
}
#endif /* _RINGBUFFER_H_ */
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