/*-
* Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
* Copyright (c) 2008-2009, Lawrence Stewart <lstewart@freebsd.org>
* Copyright (c) 2010, The FreeBSD Foundation
* All rights reserved.
*
* Portions of this software were developed at the Centre for Advanced
* Internet Architectures, Swinburne University of Technology, Melbourne,
* Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
*
* 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 unmodified, 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 AUTHOR ``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 AUTHOR 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.
*
* $FreeBSD$
*
*/
#ifndef _SYS_ALQ_H_
#define _SYS_ALQ_H_
/*
* Opaque type for the Async. Logging Queue
*/
struct alq;
/* The thread for the logging daemon */
extern struct thread *ald_thread;
/*
* Async. Logging Entry
*/
struct ale {
intptr_t ae_bytesused; /* # bytes written to ALE. */
char *ae_data; /* Write ptr. */
int ae_pad; /* Unused, compat. */
};
/* Flag options. */
#define ALQ_NOWAIT 0x0001 /* ALQ may not sleep. */
#define ALQ_WAITOK 0x0002 /* ALQ may sleep. */
#define ALQ_NOACTIVATE 0x0004 /* Don't activate ALQ after write. */
#define ALQ_ORDERED 0x0010 /* Maintain write ordering between threads. */
/* Suggested mode for file creation. */
#define ALQ_DEFAULT_CMODE 0600
/*
* alq_open_flags: Creates a new queue
*
* Arguments:
* alq Storage for a pointer to the newly created queue.
* file The filename to open for logging.
* cred Credential to authorize open and I/O with.
* cmode Creation mode for file, if new.
* size The size of the queue in bytes.
* flags ALQ_ORDERED
* Returns:
* error from open or 0 on success
*/
struct ucred;
int alq_open_flags(struct alq **alqp, const char *file, struct ucred *cred, int cmode,
int size, int flags);
int alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode,
int size, int count);
/*
* alq_writen: Write data into the queue
*
* Arguments:
* alq The queue we're writing to
* data The entry to be recorded
* len The number of bytes to write from *data
* flags (ALQ_NOWAIT || ALQ_WAITOK), ALQ_NOACTIVATE
*
* Returns:
* EWOULDBLOCK if:
* Waitok is ALQ_NOWAIT and the queue is full.
* The system is shutting down.
* 0 on success.
*/
int alq_writen(struct alq *alq, void *data, int len, int flags);
int alq_write(struct alq *alq, void *data, int flags);
/*
* alq_flush: Flush the queue out to disk
*/
void alq_flush(struct alq *alq);
/*
* alq_close: Flush the queue and free all resources.
*/
void alq_close(struct alq *alq);
/*
* alq_getn: Return an entry for direct access
*
* Arguments:
* alq The queue to retrieve an entry from
* len Max number of bytes required
* flags (ALQ_NOWAIT || ALQ_WAITOK)
*
* Returns:
* The next available ale on success.
* NULL if:
* flags is ALQ_NOWAIT and the queue is full.
* The system is shutting down.
*
* This leaves the queue locked until a subsequent alq_post.
*/
struct ale *alq_getn(struct alq *alq, int len, int flags);
struct ale *alq_get(struct alq *alq, int flags);
/*
* alq_post_flags: Schedule the ale retrieved by alq_get/alq_getn for writing.
* alq The queue to post the entry to.
* ale An asynch logging entry returned by alq_get.
* flags ALQ_NOACTIVATE
*/
void alq_post_flags(struct alq *alq, struct ale *ale, int flags);
static __inline void
alq_post(struct alq *alq, struct ale *ale)
{
alq_post_flags(alq, ale, 0);
}
#endif /* _SYS_ALQ_H_ */
