xref: /illumos-gate/usr/src/cmd/sgs/libelf/common/getscn.c (revision d7c57852794a9ac50d4b6a9c4161cb10919658aa)
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 #include "libelf.h"
31 #include "decl.h"
32 #include "msg.h"
33 
34 
35 Elf_Scn *
36 elf_getscn(Elf * elf, size_t index)
37 {
38 	Elf_Scn	*	s;
39 	Elf_Scn	*	prev_s;
40 	size_t		j = index;
41 	size_t		tabsz;
42 
43 	if (elf == 0)
44 		return (0);
45 
46 	ELFRLOCK(elf)
47 	tabsz = elf->ed_scntabsz;
48 	if (elf->ed_hdscn == 0) {
49 		ELFUNLOCK(elf)
50 		ELFWLOCK(elf)
51 		if ((elf->ed_hdscn == 0) && (_elf_cook(elf) != OK_YES)) {
52 			ELFUNLOCK(elf);
53 			return (0);
54 		}
55 		ELFUNLOCK(elf);
56 		ELFRLOCK(elf)
57 	}
58 	/*
59 	 * If the section in question is part of a table allocated
60 	 * from within _elf_prescn() then we can index straight
61 	 * to it.
62 	 */
63 	if (index < tabsz) {
64 		s = &elf->ed_hdscn[index];
65 		ELFUNLOCK(elf);
66 		return (s);
67 	}
68 
69 	if (tabsz)
70 		s = &elf->ed_hdscn[tabsz - 1];
71 	else
72 		s = elf->ed_hdscn;
73 
74 	for (prev_s = 0; s != 0; prev_s = s, s = s->s_next) {
75 		if (prev_s) {
76 			SCNUNLOCK(prev_s)
77 		}
78 		SCNLOCK(s)
79 		if (j == 0) {
80 			if (s->s_index == index) {
81 				SCNUNLOCK(s)
82 				ELFUNLOCK(elf);
83 				return (s);
84 			}
85 			_elf_seterr(EBUG_SCNLIST, 0);
86 			SCNUNLOCK(s)
87 			ELFUNLOCK(elf)
88 			return (0);
89 		}
90 		--j;
91 	}
92 	if (prev_s) {
93 		SCNUNLOCK(prev_s)
94 	}
95 
96 	_elf_seterr(EREQ_NDX, 0);
97 	ELFUNLOCK(elf);
98 	return (0);
99 }
100