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 * $FreeBSD$ 35 * 36 */ 37 #ifndef _SYS_ALQ_H_ 38 #define _SYS_ALQ_H_ 39 40 /* 41 * Opaque type for the Async. Logging Queue 42 */ 43 struct alq; 44 45 /* The thread for the logging daemon */ 46 extern struct thread *ald_thread; 47 48 /* 49 * Async. Logging Entry 50 */ 51 struct ale { 52 intptr_t ae_bytesused; /* # bytes written to ALE. */ 53 char *ae_data; /* Write ptr. */ 54 int ae_pad; /* Unused, compat. */ 55 }; 56 57 /* Flag options. */ 58 #define ALQ_NOWAIT 0x0001 /* ALQ may not sleep. */ 59 #define ALQ_WAITOK 0x0002 /* ALQ may sleep. */ 60 #define ALQ_NOACTIVATE 0x0004 /* Don't activate ALQ after write. */ 61 #define ALQ_ORDERED 0x0010 /* Maintain write ordering between threads. */ 62 63 /* Suggested mode for file creation. */ 64 #define ALQ_DEFAULT_CMODE 0600 65 66 /* 67 * alq_open_flags: Creates a new queue 68 * 69 * Arguments: 70 * alq Storage for a pointer to the newly created queue. 71 * file The filename to open for logging. 72 * cred Credential to authorize open and I/O with. 73 * cmode Creation mode for file, if new. 74 * size The size of the queue in bytes. 75 * flags ALQ_ORDERED 76 * Returns: 77 * error from open or 0 on success 78 */ 79 struct ucred; 80 int alq_open_flags(struct alq **alqp, const char *file, struct ucred *cred, int cmode, 81 int size, int flags); 82 int alq_open(struct alq **alqp, const char *file, struct ucred *cred, int cmode, 83 int size, int count); 84 85 /* 86 * alq_writen: Write data into the queue 87 * 88 * Arguments: 89 * alq The queue we're writing to 90 * data The entry to be recorded 91 * len The number of bytes to write from *data 92 * flags (ALQ_NOWAIT || ALQ_WAITOK), ALQ_NOACTIVATE 93 * 94 * Returns: 95 * EWOULDBLOCK if: 96 * Waitok is ALQ_NOWAIT and the queue is full. 97 * The system is shutting down. 98 * 0 on success. 99 */ 100 int alq_writen(struct alq *alq, void *data, int len, int flags); 101 int alq_write(struct alq *alq, void *data, int flags); 102 103 /* 104 * alq_flush: Flush the queue out to disk 105 */ 106 void alq_flush(struct alq *alq); 107 108 /* 109 * alq_close: Flush the queue and free all resources. 110 */ 111 void alq_close(struct alq *alq); 112 113 /* 114 * alq_getn: Return an entry for direct access 115 * 116 * Arguments: 117 * alq The queue to retrieve an entry from 118 * len Max number of bytes required 119 * flags (ALQ_NOWAIT || ALQ_WAITOK) 120 * 121 * Returns: 122 * The next available ale on success. 123 * NULL if: 124 * flags is ALQ_NOWAIT and the queue is full. 125 * The system is shutting down. 126 * 127 * This leaves the queue locked until a subsequent alq_post. 128 */ 129 struct ale *alq_getn(struct alq *alq, int len, int flags); 130 struct ale *alq_get(struct alq *alq, int flags); 131 132 /* 133 * alq_post_flags: Schedule the ale retrieved by alq_get/alq_getn for writing. 134 * alq The queue to post the entry to. 135 * ale An asynch logging entry returned by alq_get. 136 * flags ALQ_NOACTIVATE 137 */ 138 void alq_post_flags(struct alq *alq, struct ale *ale, int flags); 139 140 static __inline void 141 alq_post(struct alq *alq, struct ale *ale) 142 { 143 alq_post_flags(alq, ale, 0); 144 } 145 146 #endif /* _SYS_ALQ_H_ */ 147