xref: /illumos-gate/usr/src/cmd/sgs/libelf/common/strptr.c (revision 3db86aab)
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 /*	Copyright (c) 1988 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 /*
27  * Copyright (c) 1998 by Sun Microsystems, Inc.
28  * All rights reserved.
29  */
30 
31 #pragma ident	"%Z%%M%	%I%	%E% SMI" 	/* SVr4.0 1.6	*/
32 
33 #pragma weak	elf_strptr = _elf_strptr
34 
35 
36 #include "syn.h"
37 #include "libelf.h"
38 #include "decl.h"
39 #include "msg.h"
40 
41 
42 char *
43 elf_strptr(Elf * elf, size_t ndx, size_t off)
44 {
45 	Elf_Scn *	s;
46 	Elf_Data *	d;
47 	char *		rc;
48 
49 	if (elf == 0)
50 		return (0);
51 	if ((s = elf_getscn(elf, ndx)) == 0) {
52 		_elf_seterr(EREQ_STRSCN, 0);
53 		return (0);
54 	}
55 	READLOCKS(elf, s)
56 	if (elf->ed_class == ELFCLASS32) {
57 		Elf32_Shdr* sh = (Elf32_Shdr*)s->s_shdr;
58 
59 		if ((sh == 0) || (sh->sh_type != SHT_STRTAB)) {
60 			_elf_seterr(EREQ_STRSCN, 0);
61 			READUNLOCKS(elf, s)
62 			return (0);
63 		}
64 	} else if (elf->ed_class == ELFCLASS64) {
65 		Elf64_Shdr* sh = (Elf64_Shdr*)s->s_shdr;
66 
67 		if ((sh == 0) || (sh->sh_type != SHT_STRTAB)) {
68 			_elf_seterr(EREQ_STRSCN, 0);
69 			READUNLOCKS(elf, s)
70 			return (0);
71 		}
72 	} else {
73 		_elf_seterr(EREQ_STRSCN, 0);
74 		READUNLOCKS(elf, s)
75 		return (0);
76 	}
77 
78 
79 	/*
80 	 * If the layout bit is set, use the offsets and
81 	 * sizes in the data buffers.  Otherwise, take
82 	 * data buffers in order.
83 	 */
84 
85 	d = 0;
86 	if (elf->ed_uflags & ELF_F_LAYOUT) {
87 		while ((d = _elf_locked_getdata(s, d)) != 0) {
88 			if (d->d_buf == 0)
89 				continue;
90 			if ((off >= d->d_off) &&
91 			    (off < d->d_off + d->d_size)) {
92 				rc = (char *)d->d_buf + off - d->d_off;
93 				READUNLOCKS(elf, s)
94 				return (rc);
95 			}
96 		}
97 	} else {
98 		size_t	sz = 0, j;
99 		while ((d = _elf_locked_getdata(s, d)) != 0) {
100 			if (((j = d->d_align) > 1) && (sz % j != 0)) {
101 				j -= sz % j;
102 				sz += j;
103 				if (off < j)
104 					break;
105 				off -= j;
106 			}
107 			if (d->d_buf != 0) {
108 				if (off < d->d_size) {
109 					rc = (char *)d->d_buf + off;
110 					READUNLOCKS(elf, s)
111 					return (rc);
112 				}
113 			}
114 			sz += d->d_size;
115 			if (off < d->d_size)
116 				break;
117 			off -= d->d_size;
118 		}
119 	}
120 	_elf_seterr(EREQ_STROFF, 0);
121 	READUNLOCKS(elf, s)
122 	return (0);
123 }
124