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, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 2003 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26 
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28 
  29 #include <sys/systm.h>
  30 #include <sys/param.h>
  31 #include <sys/atomic.h>
  32 #include <sys/kmem.h>
  33 #include <sys/refstr.h>
  34 #include <sys/refstr_impl.h>
  35 
  36 refstr_t *
  37 refstr_alloc(const char *str)
  38 {
  39         refstr_t *rsp;
  40         size_t size = sizeof (rsp->rs_size) + sizeof (rsp->rs_refcnt) +
  41                 strlen(str) + 1;
  42 
  43         ASSERT(size <= UINT32_MAX);
  44         rsp = kmem_alloc(size, KM_SLEEP);
  45         rsp->rs_size = (uint32_t)size;
  46         rsp->rs_refcnt = 1;
  47         (void) strcpy(rsp->rs_string, str);
  48         return (rsp);
  49 }
  50 
  51 const char *
  52 refstr_value(refstr_t *rsp)
  53 {
  54         return (rsp != NULL ? (const char *)rsp->rs_string : NULL);
  55 }
  56 
  57 void
  58 refstr_hold(refstr_t *rsp)
  59 {
  60         atomic_add_32(&rsp->rs_refcnt, 1);
  61 }
  62 
  63 void
  64 refstr_rele(refstr_t *rsp)
  65 {
  66         if (atomic_add_32_nv(&rsp->rs_refcnt, -1) == 0)
  67                 kmem_free(rsp, (size_t)rsp->rs_size);
  68 }