144 lines
3.6 KiB
C
144 lines
3.6 KiB
C
/*-
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* Copyright (c) 2010 The FreeBSD Foundation
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* All rights reserved.
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*
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* This software was developed by Pawel Jakub Dawidek under sponsorship from
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* the FreeBSD Foundation.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/queue.h>
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#include <stdbool.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <pjdlog.h>
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#include "rangelock.h"
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#ifndef PJDLOG_ASSERT
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#include <assert.h>
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#define PJDLOG_ASSERT(...) assert(__VA_ARGS__)
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#endif
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#define RANGELOCKS_MAGIC 0x94310c
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struct rangelocks {
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int rls_magic; /* Magic value. */
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TAILQ_HEAD(, rlock) rls_locks; /* List of locked ranges. */
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};
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struct rlock {
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off_t rl_start;
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off_t rl_end;
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TAILQ_ENTRY(rlock) rl_next;
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};
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int
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rangelock_init(struct rangelocks **rlsp)
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{
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struct rangelocks *rls;
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PJDLOG_ASSERT(rlsp != NULL);
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rls = malloc(sizeof(*rls));
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if (rls == NULL)
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return (-1);
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TAILQ_INIT(&rls->rls_locks);
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rls->rls_magic = RANGELOCKS_MAGIC;
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*rlsp = rls;
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return (0);
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}
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void
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rangelock_free(struct rangelocks *rls)
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{
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struct rlock *rl;
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PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC);
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rls->rls_magic = 0;
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while ((rl = TAILQ_FIRST(&rls->rls_locks)) != NULL) {
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TAILQ_REMOVE(&rls->rls_locks, rl, rl_next);
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free(rl);
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}
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free(rls);
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}
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int
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rangelock_add(struct rangelocks *rls, off_t offset, off_t length)
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{
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struct rlock *rl;
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PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC);
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rl = malloc(sizeof(*rl));
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if (rl == NULL)
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return (-1);
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rl->rl_start = offset;
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rl->rl_end = offset + length;
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TAILQ_INSERT_TAIL(&rls->rls_locks, rl, rl_next);
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return (0);
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}
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void
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rangelock_del(struct rangelocks *rls, off_t offset, off_t length)
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{
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struct rlock *rl;
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PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC);
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TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) {
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if (rl->rl_start == offset && rl->rl_end == offset + length)
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break;
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}
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PJDLOG_ASSERT(rl != NULL);
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TAILQ_REMOVE(&rls->rls_locks, rl, rl_next);
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free(rl);
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}
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bool
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rangelock_islocked(struct rangelocks *rls, off_t offset, off_t length)
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{
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struct rlock *rl;
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PJDLOG_ASSERT(rls->rls_magic == RANGELOCKS_MAGIC);
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TAILQ_FOREACH(rl, &rls->rls_locks, rl_next) {
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if (rl->rl_start >= offset && rl->rl_start < offset + length)
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break;
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else if (rl->rl_end > offset && rl->rl_end <= offset + length)
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break;
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else if (rl->rl_start < offset && rl->rl_end > offset + length)
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break;
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}
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return (rl != NULL);
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}
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