1 /*- 2 * Copyright (c) 2002, Jeffrey Roberson <jeff@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 * 28 */ 29 #ifndef _SYS_ALQ_H_ 30 #define _SYS_ALQ_H_ 31 32 /* 33 * Opaque type for the Async. Logging Queue 34 */ 35 struct alq; 36 37 /* The thread for the logging daemon */ 38 extern struct thread *ald_thread; 39 40 /* 41 * Async. Logging Entry 42 */ 43 struct ale { 44 struct ale *ae_next; /* Next Entry */ 45 char *ae_data; /* Entry buffer */ 46 int ae_flags; /* Entry flags */ 47 }; 48 49 #define AE_VALID 0x0001 /* Entry has valid data */ 50 51 52 /* waitok options */ 53 #define ALQ_NOWAIT 0x0001 54 #define ALQ_WAITOK 0x0002 55 56 /* Suggested mode for file creation. */ 57 #define ALQ_DEFAULT_CMODE 0600 58 59 /* 60 * alq_open: Creates a new queue 61 * 62 * Arguments: 63 * alq Storage for a pointer to the newly created queue. 64 * file The filename to open for logging. 65 * cred Credential to authorize open and I/O with. 66 * cmode Creation mode for file, if new. 67 * size The size of each entry in the queue. 68 * count The number of items in the buffer, this should be large enough 69 * to store items over the period of a disk write. 70 * Returns: 71 * error from open or 0 on success 72 */ 73 struct ucred; 74 int alq_open(struct alq **, const char *file, struct ucred *cred, int cmode, 75 int size, int count); 76 77 /* 78 * alq_write: Write data into the queue 79 * 80 * Arguments: 81 * alq The queue we're writing to 82 * data The entry to be recorded 83 * waitok Are we permitted to wait? 84 * 85 * Returns: 86 * EWOULDBLOCK if: 87 * Waitok is ALQ_NOWAIT and the queue is full. 88 * The system is shutting down. 89 * 0 on success. 90 */ 91 int alq_write(struct alq *alq, void *data, int waitok); 92 93 /* 94 * alq_flush: Flush the queue out to disk 95 */ 96 void alq_flush(struct alq *alq); 97 98 /* 99 * alq_close: Flush the queue and free all resources. 100 */ 101 void alq_close(struct alq *alq); 102 103 /* 104 * alq_get: Return an entry for direct access 105 * 106 * Arguments: 107 * alq The queue to retrieve an entry from 108 * waitok Are we permitted to wait? 109 * 110 * Returns: 111 * The next available ale on success. 112 * NULL if: 113 * Waitok is ALQ_NOWAIT and the queue is full. 114 * The system is shutting down. 115 * 116 * This leaves the queue locked until a subsequent alq_post. 117 */ 118 struct ale *alq_get(struct alq *alq, int waitok); 119 120 /* 121 * alq_post: Schedule the ale retrieved by alq_get for writing. 122 * alq The queue to post the entry to. 123 * ale An asynch logging entry returned by alq_get. 124 */ 125 void alq_post(struct alq *, struct ale *); 126 127 #endif /* _SYS_ALQ_H_ */ 128