xref: /titanic_41/usr/src/cmd/sgs/libelf/common/newdata.c (revision 7c2fbfb345896881c631598ee3852ce9ce33fb07)
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 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1988 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 #pragma ident	"%Z%%M%	%I%	%E% SMI"
31 
32 #include "libelf.h"
33 #include "decl.h"
34 #include "msg.h"
35 
36 
37 Elf_Data *
38 elf_newdata(Elf_Scn * s)
39 {
40 	Dnode *		d;
41 	Elf_Data *	rc;
42 	Elf *		elf;
43 	unsigned	work;
44 
45 	if (s == 0)
46 		return (0);
47 	elf = s->s_elf;
48 	READLOCKS(elf, s)
49 	if (s->s_index == SHN_UNDEF) {
50 		_elf_seterr(EREQ_SCNNULL, 0);
51 		READUNLOCKS(elf, s)
52 		return (0);
53 	}
54 
55 	if ((s->s_myflags & SF_READY) == 0) {
56 		UPGRADELOCKS(elf, s)
57 		/*
58 		 * re-confirm that another 'thread' hasn't come along
59 		 * and cooked this section while the locks were
60 		 * obtained.
61 		 */
62 		if ((s->s_myflags & SF_READY) == 0)
63 			(void) _elf_cookscn(s);
64 		DOWNGRADELOCKS(elf, s)
65 	}
66 
67 	/*
68 	 * If this is the first new node, use the one allocated
69 	 * in the scn itself.  Update data buffer in both cases.
70 	 */
71 	ELFACCESSDATA(work, _elf_work)
72 	if (s->s_hdnode == 0) {
73 		s->s_dnode.db_uflags |= ELF_F_DIRTY;
74 		s->s_dnode.db_myflags |= DBF_READY;
75 		s->s_hdnode = &s->s_dnode;
76 		s->s_tlnode = &s->s_dnode;
77 		s->s_dnode.db_scn = s;
78 		s->s_dnode.db_data.d_version = work;
79 		rc = &s->s_dnode.db_data;
80 		READUNLOCKS(elf, s)
81 		return (rc);
82 	}
83 	if ((d = _elf_dnode()) == 0) {
84 		READUNLOCKS(elf, s)
85 		return (0);
86 	}
87 	NOTE(NOW_INVISIBLE_TO_OTHER_THREADS(*d))
88 	d->db_data.d_version = work;
89 	d->db_scn = s;
90 	d->db_uflags |= ELF_F_DIRTY;
91 	d->db_myflags |= DBF_READY;
92 	s->s_tlnode->db_next = d;
93 	s->s_tlnode = d;
94 	rc = &d->db_data;
95 	NOTE(NOW_VISIBLE_TO_OTHER_THREADS(*d))
96 	READUNLOCKS(elf, s)
97 	return (rc);
98 }
99