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 <stdbool.h> 36 #include <stdlib.h> 37 #include <unistd.h> 38 39 #include <pjdlog.h> 40 41 #include "rangelock.h" 42 43 #ifndef PJDLOG_ASSERT 44 #include <assert.h> 45 #define PJDLOG_ASSERT(...) assert(__VA_ARGS__) 46 #endif 47 48 #define RANGELOCKS_MAGIC 0x94310c 49 struct rangelocks { 50 int rls_magic; /* Magic value. */ 51 TAILQ_HEAD(, rlock) rls_locks; /* List of locked ranges. */ 52 }; 53 54 struct rlock { 55 off_t rl_start; 56 off_t rl_end; 57 TAILQ_ENTRY(rlock) rl_next; 58 }; 59 60 int 61 rangelock_init(struct rangelocks **rlsp) 62 { 63 struct rangelocks *rls; 64 65 PJDLOG_ASSERT(rlsp != NULL); 66 67 rls = malloc(sizeof(*rls)); 68 if (rls == NULL) 69 return (-1); 70 71 TAILQ_INIT(&rls->rls_locks); 72 73 rls->rls_magic = RANGELOCKS_MAGIC; 74 *rlsp = rls; 75 76 return (0); 77 } 78 79 void 80 rangelock_free(struct rangelocks *rls) 81 { 82 struct rlock *rl; 83 84 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 85 86 rls->rls_magic = 0; 87 88 while ((rl = TAILQ_FIRST(&rls->rls_locks)) != NULL) { 89 TAILQ_REMOVE(&rls->rls_locks, rl, rl_next); 90 free(rl); 91 } 92 free(rls); 93 } 94 95 int 96 rangelock_add(struct rangelocks *rls, off_t offset, off_t length) 97 { 98 struct rlock *rl; 99 100 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 101 102 rl = malloc(sizeof(*rl)); 103 if (rl == NULL) 104 return (-1); 105 rl->rl_start = offset; 106 rl->rl_end = offset + length; 107 TAILQ_INSERT_TAIL(&rls->rls_locks, rl, rl_next); 108 return (0); 109 } 110 111 void 112 rangelock_del(struct rangelocks *rls, off_t offset, off_t length) 113 { 114 struct rlock *rl; 115 116 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 117 118 TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) { 119 if (rl->rl_start == offset && rl->rl_end == offset + length) 120 break; 121 } 122 PJDLOG_ASSERT(rl != NULL); 123 TAILQ_REMOVE(&rls->rls_locks, rl, rl_next); 124 free(rl); 125 } 126 127 bool 128 rangelock_islocked(struct rangelocks *rls, off_t offset, off_t length) 129 { 130 struct rlock *rl; 131 off_t end; 132 133 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 134 135 end = offset + length; 136 TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) { 137 if (rl->rl_start < end && rl->rl_end > offset) 138 break; 139 } 140 return (rl != NULL); 141 } 142