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