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