1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org>
5 * Copyright (c) 2008-2009, Lawrence Stewart <lstewart@freebsd.org>
6 * Copyright (c) 2010, The FreeBSD Foundation
7 * All rights reserved.
8 *
9 * Portions of this software were developed at the Centre for Advanced
10 * Internet Architectures, Swinburne University of Technology, Melbourne,
11 * Australia by Lawrence Stewart under sponsorship from the FreeBSD Foundation.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice unmodified, this list of conditions, and the following
18 * disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
24 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
25 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
26 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
27 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
28 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
29 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
30 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
31 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
32 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
33 *
34 */
35#ifndef _SYS_ALQ_H_
36#define _SYS_ALQ_H_
37
38#ifdef _KERNEL
39/*
40 * Opaque type for the Async. Logging Queue
41 */
42struct alq;
43
44/* The thread for the logging daemon */
45extern struct thread *ald_thread;
46
47/*
48 * Async. Logging Entry
49 */
50struct ale {
51 intptr_t ae_bytesused; /* # bytes written to ALE. */
52 char *ae_data; /* Write ptr. */
53 int ae_pad; /* Unused, compat. */
54};
55
56/* Flag options. */
57#define ALQ_NOWAIT 0x0001 /* ALQ may not sleep. */
58#define ALQ_WAITOK 0x0002 /* ALQ may sleep. */
59#define ALQ_NOACTIVATE 0x0004 /* Don't activate ALQ after write. */
60#define ALQ_ORDERED 0x0010 /* Maintain write ordering between threads. */
61
62/* Suggested mode for file creation. */
63#define ALQ_DEFAULT_CMODE 0600
64
65/*
66 * alq_open_flags: Creates a new queue
67 *
68 * Arguments:
69 * alq Storage for a pointer to the newly created queue.
70 * file The filename to open for logging.
71 * cred Credential to authorize open and I/O with.
72 * cmode Creation mode for file, if new.
73 * size The size of the queue in bytes.
74 * flags ALQ_ORDERED
75 * Returns:
76 * error from open or 0 on success
77 */
78struct ucred;
79int alq_open_flags(struct alq **alqp, const char *file, struct ucred *cred, int cmode,
80 int size, int flags);
81int alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode,
82 int size, int count);
83
84/*
85 * alq_writen: Write data into the queue
86 *
87 * Arguments:
88 * alq The queue we're writing to
89 * data The entry to be recorded
90 * len The number of bytes to write from *data
91 * flags (ALQ_NOWAIT || ALQ_WAITOK), ALQ_NOACTIVATE
92 *
93 * Returns:
94 * EWOULDBLOCK if:
95 * Waitok is ALQ_NOWAIT and the queue is full.
96 * The system is shutting down.
97 * 0 on success.
98 */
99int alq_writen(struct alq *alq, void *data, int len, int flags);
100int alq_write(struct alq *alq, void *data, int flags);
101
102/*
103 * alq_flush: Flush the queue out to disk
104 */
105void alq_flush(struct alq *alq);
106
107/*
108 * alq_close: Flush the queue and free all resources.
109 */
110void alq_close(struct alq *alq);
111
112/*
113 * alq_getn: Return an entry for direct access
114 *
115 * Arguments:
116 * alq The queue to retrieve an entry from
117 * len Max number of bytes required
118 * flags (ALQ_NOWAIT || ALQ_WAITOK)
119 *
120 * Returns:
121 * The next available ale on success.
122 * NULL if:
123 * flags is ALQ_NOWAIT and the queue is full.
124 * The system is shutting down.
125 *
126 * This leaves the queue locked until a subsequent alq_post.
127 */
128struct ale *alq_getn(struct alq *alq, int len, int flags);
129struct ale *alq_get(struct alq *alq, int flags);
130
131/*
132 * alq_post_flags: Schedule the ale retrieved by alq_get/alq_getn for writing.
133 * alq The queue to post the entry to.
134 * ale An asynch logging entry returned by alq_get.
135 * flags ALQ_NOACTIVATE
136 */
137void alq_post_flags(struct alq *alq, struct ale *ale, int flags);
138
139static __inline void
140alq_post(struct alq *alq, struct ale *ale)
141{
142 alq_post_flags(alq, ale, 0);
143}
144
145#endif /* _KERNEL */
146#endif /* _SYS_ALQ_H_ */