1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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: stable/11/sbin/hastd/rangelock.c 330449 2018-03-05 07:26:05Z eadler $");
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
51struct rangelocks {
52	int	 rls_magic;		/* Magic value. */
53	TAILQ_HEAD(, rlock) rls_locks;	/* List of locked ranges. */
54};
55
56struct rlock {
57	off_t	rl_start;
58	off_t	rl_end;
59	TAILQ_ENTRY(rlock) rl_next;
60};
61
62int
63rangelock_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
81void
82rangelock_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
97int
98rangelock_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
113void
114rangelock_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
129bool
130rangelock_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