xref: /titanic_41/usr/src/uts/common/os/refstr.c (revision c6a664189ff58eecb65704097a089f0bb4d35523)
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 #include <sys/systm.h>
28 #include <sys/param.h>
29 #include <sys/atomic.h>
30 #include <sys/kmem.h>
31 #include <sys/refstr.h>
32 #include <sys/refstr_impl.h>
33 
34 refstr_t *
35 refstr_alloc(const char *str)
36 {
37 	refstr_t *rsp;
38 	size_t size = sizeof (rsp->rs_size) + sizeof (rsp->rs_refcnt) +
39 		strlen(str) + 1;
40 
41 	ASSERT(size <= UINT32_MAX);
42 	rsp = kmem_alloc(size, KM_SLEEP);
43 	rsp->rs_size = (uint32_t)size;
44 	rsp->rs_refcnt = 1;
45 	(void) strcpy(rsp->rs_string, str);
46 	return (rsp);
47 }
48 
49 const char *
50 refstr_value(refstr_t *rsp)
51 {
52 	return (rsp != NULL ? (const char *)rsp->rs_string : NULL);
53 }
54 
55 void
56 refstr_hold(refstr_t *rsp)
57 {
58 	atomic_inc_32(&rsp->rs_refcnt);
59 }
60 
61 void
62 refstr_rele(refstr_t *rsp)
63 {
64 	if (atomic_dec_32_nv(&rsp->rs_refcnt) == 0)
65 		kmem_free(rsp, (size_t)rsp->rs_size);
66 }
67