quota.c

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/*
 * Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
 * Copyright (C) 2000, 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: quota.c,v 1.18 2007/06/19 23:47:17 tbox Exp $ */

/*! \file */

#include <config.h>

#include <stddef.h>

#include <isc/quota.h>
#include <isc/util.h>

isc_result_t
isc_quota_init(isc_quota_t *quota, int max) {
        quota->max = max;
        quota->used = 0;
        quota->soft = 0;
        return (isc_mutex_init(&quota->lock));
}

void
isc_quota_destroy(isc_quota_t *quota) {
        INSIST(quota->used == 0);
        quota->max = 0;
        quota->used = 0;
        quota->soft = 0;
        DESTROYLOCK(&quota->lock);
}

void
isc_quota_soft(isc_quota_t *quota, int soft) {
        LOCK(&quota->lock);
        quota->soft = soft;
        UNLOCK(&quota->lock);
}

void
isc_quota_max(isc_quota_t *quota, int max) {
        LOCK(&quota->lock);
        quota->max = max;
        UNLOCK(&quota->lock);
}

isc_result_t
isc_quota_reserve(isc_quota_t *quota) {
        isc_result_t result;
        LOCK(&quota->lock);
        if (quota->max == 0 || quota->used < quota->max) {
                if (quota->soft == 0 || quota->used < quota->soft)
                        result = ISC_R_SUCCESS;
                else
                        result = ISC_R_SOFTQUOTA;
                quota->used++;
        } else
                result = ISC_R_QUOTA;
        UNLOCK(&quota->lock);
        return (result);
}

void
isc_quota_release(isc_quota_t *quota) {
        LOCK(&quota->lock);
        INSIST(quota->used > 0);
        quota->used--;
        UNLOCK(&quota->lock);
}

isc_result_t
isc_quota_attach(isc_quota_t *quota, isc_quota_t **p)
{
        isc_result_t result;
        INSIST(p != NULL && *p == NULL);
        result = isc_quota_reserve(quota);
        if (result == ISC_R_SUCCESS || result == ISC_R_SOFTQUOTA)
                *p = quota;
        return (result);
}

void
isc_quota_detach(isc_quota_t **p)
{
        INSIST(p != NULL && *p != NULL);
        isc_quota_release(*p);
        *p = NULL;
}

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