quota.c 2.21 KB
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/*
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 * Copyright (C) 2004, 2005  Internet Systems Consortium, Inc. ("ISC")
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 * Copyright (C) 2000, 2001  Internet Software Consortium.
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 *
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 * Permission to use, copy, modify, and 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.
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 *
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 * 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.
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 */
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/* $Id: quota.c,v 1.15 2005/04/29 00:23:29 marka Exp $ */
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/*! \file */
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#include <config.h>
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#include <stddef.h>

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#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;
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	quota->soft = ISC_FALSE;
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	return (isc_mutex_init(&quota->lock));
}

void
isc_quota_destroy(isc_quota_t *quota) {
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	INSIST(quota->used == 0);
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	quota->max = -1;
	quota->used = -1;
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	quota->soft = ISC_FALSE;
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	DESTROYLOCK(&quota->lock);
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}

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void
isc_quota_soft(isc_quota_t *quota, isc_boolean_t soft) {
	quota->soft = soft;
}

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

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

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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);
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	if (result == ISC_R_SUCCESS || result == ISC_R_SOFTQUOTA)
		*p = quota;
	return (result);
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}
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void
isc_quota_detach(isc_quota_t **p)
{
	INSIST(p != NULL && *p != NULL);
	isc_quota_release(*p);
	*p = NULL;
}