1 /*- 2 * Copyright (c) 2010 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * This software was developed by Pawel Jakub Dawidek under sponsorship from 6 * the FreeBSD Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/queue.h> 34 35 #include <assert.h> 36 #include <stdbool.h> 37 #include <stdlib.h> 38 #include <unistd.h> 39 40 #include "rangelock.h" 41 42 #define RANGELOCKS_MAGIC 0x94310c 43 struct rangelocks { 44 int rls_magic; /* Magic value. */ 45 TAILQ_HEAD(, rlock) rls_locks; /* List of locked ranges. */ 46 }; 47 48 struct rlock { 49 off_t rl_start; 50 off_t rl_end; 51 TAILQ_ENTRY(rlock) rl_next; 52 }; 53 54 int 55 rangelock_init(struct rangelocks **rlsp) 56 { 57 struct rangelocks *rls; 58 59 assert(rlsp != NULL); 60 61 rls = malloc(sizeof(*rls)); 62 if (rls == NULL) 63 return (-1); 64 65 TAILQ_INIT(&rls->rls_locks); 66 67 rls->rls_magic = RANGELOCKS_MAGIC; 68 *rlsp = rls; 69 70 return (0); 71 } 72 73 void 74 rangelock_free(struct rangelocks *rls) 75 { 76 struct rlock *rl; 77 78 assert(rls->rls_magic == RANGELOCKS_MAGIC); 79 80 rls->rls_magic = 0; 81 82 while ((rl = TAILQ_FIRST(&rls->rls_locks)) != NULL) { 83 TAILQ_REMOVE(&rls->rls_locks, rl, rl_next); 84 free(rl); 85 } 86 free(rls); 87 } 88 89 int 90 rangelock_add(struct rangelocks *rls, off_t offset, off_t length) 91 { 92 struct rlock *rl; 93 94 assert(rls->rls_magic == RANGELOCKS_MAGIC); 95 96 rl = malloc(sizeof(*rl)); 97 if (rl == NULL) 98 return (-1); 99 rl->rl_start = offset; 100 rl->rl_end = offset + length; 101 TAILQ_INSERT_TAIL(&rls->rls_locks, rl, rl_next); 102 return (0); 103 } 104 105 void 106 rangelock_del(struct rangelocks *rls, off_t offset, off_t length) 107 { 108 struct rlock *rl; 109 110 assert(rls->rls_magic == RANGELOCKS_MAGIC); 111 112 TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) { 113 if (rl->rl_start == offset && rl->rl_end == offset + length) 114 break; 115 } 116 assert(rl != NULL); 117 TAILQ_REMOVE(&rls->rls_locks, rl, rl_next); 118 free(rl); 119 } 120 121 bool 122 rangelock_islocked(struct rangelocks *rls, off_t offset, off_t length) 123 { 124 struct rlock *rl; 125 126 assert(rls->rls_magic == RANGELOCKS_MAGIC); 127 128 TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) { 129 if (rl->rl_start >= offset && rl->rl_start < offset + length) 130 break; 131 else if (rl->rl_end > offset && rl->rl_end <= offset + length) 132 break; 133 else if (rl->rl_start < offset && rl->rl_end > offset + length) 134 break; 135 } 136 return (rl != NULL); 137 } 138