1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2010 The FreeBSD Foundation 5 * All rights reserved. 6 * 7 * This software was developed by Pawel Jakub Dawidek under sponsorship from 8 * the FreeBSD Foundation. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __FBSDID("$FreeBSD$"); 34 35 #include <sys/queue.h> 36 37 #include <stdbool.h> 38 #include <stdlib.h> 39 #include <unistd.h> 40 41 #include <pjdlog.h> 42 43 #include "rangelock.h" 44 45 #ifndef PJDLOG_ASSERT 46 #include <assert.h> 47 #define PJDLOG_ASSERT(...) assert(__VA_ARGS__) 48 #endif 49 50 #define RANGELOCKS_MAGIC 0x94310c 51 struct rangelocks { 52 int rls_magic; /* Magic value. */ 53 TAILQ_HEAD(, rlock) rls_locks; /* List of locked ranges. */ 54 }; 55 56 struct rlock { 57 off_t rl_start; 58 off_t rl_end; 59 TAILQ_ENTRY(rlock) rl_next; 60 }; 61 62 int 63 rangelock_init(struct rangelocks **rlsp) 64 { 65 struct rangelocks *rls; 66 67 PJDLOG_ASSERT(rlsp != NULL); 68 69 rls = malloc(sizeof(*rls)); 70 if (rls == NULL) 71 return (-1); 72 73 TAILQ_INIT(&rls->rls_locks); 74 75 rls->rls_magic = RANGELOCKS_MAGIC; 76 *rlsp = rls; 77 78 return (0); 79 } 80 81 void 82 rangelock_free(struct rangelocks *rls) 83 { 84 struct rlock *rl; 85 86 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 87 88 rls->rls_magic = 0; 89 90 while ((rl = TAILQ_FIRST(&rls->rls_locks)) != NULL) { 91 TAILQ_REMOVE(&rls->rls_locks, rl, rl_next); 92 free(rl); 93 } 94 free(rls); 95 } 96 97 int 98 rangelock_add(struct rangelocks *rls, off_t offset, off_t length) 99 { 100 struct rlock *rl; 101 102 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 103 104 rl = malloc(sizeof(*rl)); 105 if (rl == NULL) 106 return (-1); 107 rl->rl_start = offset; 108 rl->rl_end = offset + length; 109 TAILQ_INSERT_TAIL(&rls->rls_locks, rl, rl_next); 110 return (0); 111 } 112 113 void 114 rangelock_del(struct rangelocks *rls, off_t offset, off_t length) 115 { 116 struct rlock *rl; 117 118 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 119 120 TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) { 121 if (rl->rl_start == offset && rl->rl_end == offset + length) 122 break; 123 } 124 PJDLOG_ASSERT(rl != NULL); 125 TAILQ_REMOVE(&rls->rls_locks, rl, rl_next); 126 free(rl); 127 } 128 129 bool 130 rangelock_islocked(struct rangelocks *rls, off_t offset, off_t length) 131 { 132 struct rlock *rl; 133 off_t end; 134 135 PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC); 136 137 end = offset + length; 138 TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) { 139 if (rl->rl_start < end && rl->rl_end > offset) 140 break; 141 } 142 return (rl != NULL); 143 } 144