usr/src/cmd/nscd/nscd_wait.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #pragma ident   "%Z%%M% %I%     %E% SMI"
  27
  28 /*
  29  * routines to wait and wake up a client waiting on a list for a
  30  * name service request
  31  */
  32 #include "cache.h"
  33
  34 int
  35 nscd_wait(nsc_ctx_t *ctx, nsc_db_t *nscdb, nsc_entry_t *entry)
  36 {
  37         waiter_t        mywait;
  38         waiter_t        *wchan = &nscdb->db_wait;
  39
  40         (void) cond_init(&(mywait.w_waitcv), USYNC_THREAD, 0);
  41         mywait.w_key = entry;
  42         mywait.w_signaled = 0;
  43         mywait.w_next = wchan->w_next;
  44         mywait.w_prev = wchan;
  45         if (mywait.w_next)
  46                 mywait.w_next->w_prev = &mywait;
  47         wchan->w_next = &mywait;
  48
  49         (void) mutex_lock(&ctx->stats_mutex);
  50         ctx->stats.wait_count++;
  51         (void) mutex_unlock(&ctx->stats_mutex);
  52
  53         while (!mywait.w_signaled)
  54                 (void) cond_wait(&(mywait.w_waitcv), &nscdb->db_mutex);
  55         if (mywait.w_prev)
  56                 mywait.w_prev->w_next = mywait.w_next;
  57         if (mywait.w_next)
  58                 mywait.w_next->w_prev = mywait.w_prev;
  59         return (0);
  60 }
  61
  62 int
  63 nscd_signal(nsc_ctx_t *ctx, nsc_db_t *nscdb, nsc_entry_t *entry)
  64 {
  65         int             c = 0;
  66         waiter_t        *wchan = &nscdb->db_wait;
  67         waiter_t        *tmp = wchan->w_next;
  68
  69         while (tmp) {
  70                 if (tmp->w_key == entry) {
  71                         (void) cond_signal(&(tmp->w_waitcv));
  72                         tmp->w_signaled = 1;
  73
  74                         (void) mutex_lock(&ctx->stats_mutex);
  75                         ctx->stats.wait_count--;
  76                         (void) mutex_unlock(&ctx->stats_mutex);
  77                         c++;
  78                 }
  79                 tmp = tmp->w_next;
  80         }
  81
  82         return (c);
  83 }