elf_shstrndx.c revision 164190 
1/*-
2 * Copyright (c) 2006 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/lib/libelf/elf_shstrndx.c 164190 2006-11-11 17:16:35Z jkoshy $");
29
30#include <ar.h>
31#include <libelf.h>
32
33#include "_libelf.h"
34
35/*
36 * Helpers to get/set the e_shstrndx field of the ELF header.
37 */
38
39int
40_libelf_getshstrndx(Elf *e, void *eh, int ec, size_t *strndx)
41{
42	Elf_Scn *scn;
43	void *sh;
44	size_t n;
45
46	n = (ec == ELFCLASS32) ? ((Elf32_Ehdr *) eh)->e_shstrndx :
47	    ((Elf64_Ehdr *) eh)->e_shstrndx;
48
49	if (n < SHN_LORESERVE) {
50		*strndx = n;
51		return (1);
52	}
53
54	if ((scn = elf_getscn(e, (size_t) SHN_UNDEF)) == NULL)
55		return (0);
56	if ((sh = _libelf_getshdr(scn, ec)) == NULL)
57		return (0);
58
59	if (ec == ELFCLASS32)
60		*strndx = ((Elf32_Shdr *) sh)->sh_link;
61	else
62		*strndx = ((Elf64_Shdr *) sh)->sh_link;
63
64	return (1);
65}
66
67int
68_libelf_setshstrndx(Elf *e, void *eh, int ec, size_t strndx)
69{
70	Elf_Scn *scn;
71	void *sh;
72
73	if (strndx < SHN_LORESERVE) {
74		if (ec == ELFCLASS32)
75			((Elf32_Ehdr *) eh)->e_shstrndx = strndx;
76		else
77			((Elf64_Ehdr *) eh)->e_shstrndx = strndx;
78		return (1);
79	}
80
81	if ((scn = elf_getscn(e, (size_t) SHN_UNDEF)) == NULL)
82		return (0);
83	if ((sh = _libelf_getshdr(scn, ec)) == NULL)
84		return (0);
85
86	if (ec == ELFCLASS32) {
87		((Elf32_Ehdr *) eh)->e_shstrndx = SHN_XINDEX;
88		((Elf32_Shdr *) sh)->sh_link = strndx;
89	} else {
90		((Elf64_Ehdr *) eh)->e_shstrndx = SHN_XINDEX;
91		((Elf64_Shdr *) sh)->sh_link = strndx;
92	}
93
94	return (1);
95}
96
97int
98elf_getshstrndx(Elf *e, size_t *strndx)
99{
100	void *eh;
101	int ec;
102
103	if (e == NULL || e->e_kind != ELF_K_ELF ||
104	    ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) ||
105	    ((eh = _libelf_ehdr(e, ec, 0)) == NULL)) {
106		LIBELF_SET_ERROR(ARGUMENT, 0);
107		return (0);
108	}
109
110	return (_libelf_getshstrndx(e, eh, ec, strndx));
111}
112
113int
114elf_setshstrndx(Elf *e, size_t strndx)
115{
116	void *eh;
117	int ec;
118
119	if (e == NULL || e->e_kind != ELF_K_ELF ||
120	    ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) ||
121	    ((eh = _libelf_ehdr(e, ec, 0)) == NULL)) {
122		LIBELF_SET_ERROR(ARGUMENT, 0);
123		return (0);
124	}
125
126	return (_libelf_setshstrndx(e, eh, ec, strndx));
127}
128