xref: /titanic_41/usr/src/uts/common/os/refstr.c (revision 1e49577a7fcde812700ded04431b49d67cc57d6d)
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 }
69