quota.c revision 290001 
1/*
2 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
3 * Copyright (C) 2000, 2001  Internet Software Consortium.
4 *
5 * Permission to use, copy, modify, and/or distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
8 *
9 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
10 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
11 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
12 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
13 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
14 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
15 * PERFORMANCE OF THIS SOFTWARE.
16 */
17
18/* $Id: quota.c,v 1.18 2007/06/19 23:47:17 tbox Exp $ */
19
20/*! \file */
21
22#include <config.h>
23
24#include <stddef.h>
25
26#include <isc/quota.h>
27#include <isc/util.h>
28
29isc_result_t
30isc_quota_init(isc_quota_t *quota, int max) {
31	quota->max = max;
32	quota->used = 0;
33	quota->soft = 0;
34	return (isc_mutex_init(&quota->lock));
35}
36
37void
38isc_quota_destroy(isc_quota_t *quota) {
39	INSIST(quota->used == 0);
40	quota->max = 0;
41	quota->used = 0;
42	quota->soft = 0;
43	DESTROYLOCK(&quota->lock);
44}
45
46void
47isc_quota_soft(isc_quota_t *quota, int soft) {
48	LOCK(&quota->lock);
49	quota->soft = soft;
50	UNLOCK(&quota->lock);
51}
52
53void
54isc_quota_max(isc_quota_t *quota, int max) {
55	LOCK(&quota->lock);
56	quota->max = max;
57	UNLOCK(&quota->lock);
58}
59
60isc_result_t
61isc_quota_reserve(isc_quota_t *quota) {
62	isc_result_t result;
63	LOCK(&quota->lock);
64	if (quota->max == 0 || quota->used < quota->max) {
65		if (quota->soft == 0 || quota->used < quota->soft)
66			result = ISC_R_SUCCESS;
67		else
68			result = ISC_R_SOFTQUOTA;
69		quota->used++;
70	} else
71		result = ISC_R_QUOTA;
72	UNLOCK(&quota->lock);
73	return (result);
74}
75
76void
77isc_quota_release(isc_quota_t *quota) {
78	LOCK(&quota->lock);
79	INSIST(quota->used > 0);
80	quota->used--;
81	UNLOCK(&quota->lock);
82}
83
84isc_result_t
85isc_quota_attach(isc_quota_t *quota, isc_quota_t **p)
86{
87	isc_result_t result;
88	INSIST(p != NULL && *p == NULL);
89	result = isc_quota_reserve(quota);
90	if (result == ISC_R_SUCCESS || result == ISC_R_SOFTQUOTA)
91		*p = quota;
92	return (result);
93}
94
95void
96isc_quota_detach(isc_quota_t **p)
97{
98	INSIST(p != NULL && *p != NULL);
99	isc_quota_release(*p);
100	*p = NULL;
101}
102