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 */ 42 struct alq; 43 44 /* The thread for the logging daemon */ 45 extern struct thread *ald_thread; 46 47 /* 48 * Async. Logging Entry 49 */ 50 struct 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 */ 78 struct ucred; 79 int alq_open_flags(struct alq **alqp, const char *file, struct ucred *cred, int cmode, 80 int size, int flags); 81 int 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 */ 99 int alq_writen(struct alq *alq, void *data, int len, int flags); 100 int alq_write(struct alq *alq, void *data, int flags); 101 102 /* 103 * alq_flush: Flush the queue out to disk 104 */ 105 void alq_flush(struct alq *alq); 106 107 /* 108 * alq_close: Flush the queue and free all resources. 109 */ 110 void 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 */ 128 struct ale *alq_getn(struct alq *alq, int len, int flags); 129 struct 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 */ 137 void alq_post_flags(struct alq *alq, struct ale *ale, int flags); 138 139 static __inline void 140 alq_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_ */ 147