contrib/bind-9.2.4rc7/lib/isc/quota.c

   1 /*
   2  * Copyright (C) 2004  Internet Systems Consortium, Inc. ("ISC")
   3  * Copyright (C) 2000, 2001  Internet Software Consortium.
   4  *
   5  * Permission to use, copy, modify, and 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 1.11.2.1 2004/03/09 06:11:50 marka Exp $ */
  19
  20 #include <config.h>
  21
  22 #include <stddef.h>
  23
  24 #include <isc/quota.h>
  25 #include <isc/util.h>
  26
  27 isc_result_t
  28 isc_quota_init(isc_quota_t *quota, int max) {
  29         quota->max = max;
  30         quota->used = 0;
  31         return (isc_mutex_init(&quota->lock));
  32 }
  33
  34 void
  35 isc_quota_destroy(isc_quota_t *quota) {
  36         INSIST(quota->used == 0);
  37         quota->max = -1;
  38         quota->used = -1;
  39         DESTROYLOCK(&quota->lock);
  40 }
  41
  42 isc_result_t
  43 isc_quota_reserve(isc_quota_t *quota) {
  44         isc_result_t result;
  45         LOCK(&quota->lock);
  46         if (quota->used < quota->max) {
  47                 quota->used++;
  48                 result = ISC_R_SUCCESS;
  49         } else {
  50                 result = ISC_R_QUOTA;
  51         }
  52         UNLOCK(&quota->lock);
  53         return (result);
  54 }
  55
  56 void
  57 isc_quota_release(isc_quota_t *quota) {
  58         LOCK(&quota->lock);
  59         INSIST(quota->used > 0);
  60         quota->used--;
  61         UNLOCK(&quota->lock);
  62 }
  63
  64 isc_result_t
  65 isc_quota_attach(isc_quota_t *quota, isc_quota_t **p)
  66 {
  67         isc_result_t result;
  68         INSIST(p != NULL && *p == NULL);
  69         result = isc_quota_reserve(quota);
  70         if (result != ISC_R_SUCCESS)
  71                 return (result);
  72         *p = quota;
  73         return (ISC_R_SUCCESS);
  74 }
  75
  76 void
  77 isc_quota_detach(isc_quota_t **p)
  78 {
  79         INSIST(p != NULL && *p != NULL);
  80         isc_quota_release(*p);
  81         *p = NULL;
  82 }