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
37char *
38elf_strptr(Elf * elf, size_t ndx, size_t off)
39{
40	Elf_Scn		*s;
41	Elf_Data	*d;
42	char		*rc;
43
44	if (elf == 0)
45		return (0);
46	if ((s = elf_getscn(elf, ndx)) == 0) {
47		_elf_seterr(EREQ_STRSCN, 0);
48		return (0);
49	}
50	READLOCKS(elf, s)
51	if (elf->ed_class == ELFCLASS32) {
52		Elf32_Shdr* sh = (Elf32_Shdr*)s->s_shdr;
53
54		if ((sh == 0) || (sh->sh_type != SHT_STRTAB)) {
55			_elf_seterr(EREQ_STRSCN, 0);
56			READUNLOCKS(elf, s)
57			return (0);
58		}
59	} else if (elf->ed_class == ELFCLASS64) {
60		Elf64_Shdr* sh = (Elf64_Shdr*)s->s_shdr;
61
62		if ((sh == 0) || (sh->sh_type != SHT_STRTAB)) {
63			_elf_seterr(EREQ_STRSCN, 0);
64			READUNLOCKS(elf, s)
65			return (0);
66		}
67	} else {
68		_elf_seterr(EREQ_STRSCN, 0);
69		READUNLOCKS(elf, s)
70		return (0);
71	}
72
73
74	/*
75	 * If the layout bit is set, use the offsets and
76	 * sizes in the data buffers.  Otherwise, take
77	 * data buffers in order.
78	 */
79
80	d = 0;
81	if (elf->ed_uflags & ELF_F_LAYOUT) {
82		while ((d = _elf_locked_getdata(s, d)) != 0) {
83			if (d->d_buf == 0)
84				continue;
85			if ((off >= d->d_off) &&
86			    (off < d->d_off + d->d_size)) {
87				rc = (char *)d->d_buf + off - d->d_off;
88				READUNLOCKS(elf, s)
89				return (rc);
90			}
91		}
92	} else {
93		size_t	sz = 0, j;
94		while ((d = _elf_locked_getdata(s, d)) != 0) {
95			if (((j = d->d_align) > 1) && (sz % j != 0)) {
96				j -= sz % j;
97				sz += j;
98				if (off < j)
99					break;
100				off -= j;
101			}
102			if (d->d_buf != 0) {
103				if (off < d->d_size) {
104					rc = (char *)d->d_buf + off;
105					READUNLOCKS(elf, s)
106					return (rc);
107				}
108			}
109			sz += d->d_size;
110			if (off < d->d_size)
111				break;
112			off -= d->d_size;
113		}
114	}
115	_elf_seterr(EREQ_STROFF, 0);
116	READUNLOCKS(elf, s)
117	return (0);
118}
119