contrib/bind-9.5.2/lib/isc/quota.c

   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
  29 isc_result_t
  30 isc_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
  37 void
  38 isc_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
  46 void
  47 isc_quota_soft(isc_quota_t *quota, int soft) {
  48         LOCK(&quota->lock);
  49         quota->soft = soft;
  50         UNLOCK(&quota->lock);
  51 }
  52
  53 void
  54 isc_quota_max(isc_quota_t *quota, int max) {
  55         LOCK(&quota->lock);
  56         quota->max = max;
  57         UNLOCK(&quota->lock);
  58 }
  59
  60 isc_result_t
  61 isc_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
  76 void
  77 isc_quota_release(isc_quota_t *quota) {
  78         LOCK(&quota->lock);
  79         INSIST(quota->used > 0);
  80         quota->used--;
  81         UNLOCK(&quota->lock);
  82 }
  83
  84 isc_result_t
  85 isc_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
  95 void
  96 isc_quota_detach(isc_quota_t **p)
  97 {
  98         INSIST(p != NULL && *p != NULL);
  99         isc_quota_release(*p);
 100         *p = NULL;
 101 }