1 /*
2 * x.elfext.c -- handle ELF format extensions
3 * Copyright (C) 2002 - 2006 Michael Riepe
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
14 *
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
18 */
19
20 #include <private.h>
21
22 #ifndef lint
23 static const char rcsid[] = "@(#) $Id: x.elfext.c,v 1.5 2009/07/07 17:57:43 michael Exp $";
24 #endif /* lint */
25
26 int
elf_getphdrnum(Elf * elf,size_t * resultp)27 elf_getphdrnum(Elf *elf, size_t *resultp) {
28 if (!elf) {
29 return -1;
30 }
31 elf_assert(elf->e_magic == ELF_MAGIC);
32 if (elf->e_kind != ELF_K_ELF) {
33 seterr(ERROR_NOTELF);
34 return -1;
35 }
36 if (!elf->e_ehdr && !_elf_cook(elf)) {
37 return -1;
38 }
39 if (resultp) {
40 *resultp = elf->e_phnum;
41 }
42 return 0;
43 }
44
45 int
elf_getshdrnum(Elf * elf,size_t * resultp)46 elf_getshdrnum(Elf *elf, size_t *resultp) {
47 size_t num = 0;
48 Elf_Scn *scn;
49
50 if (!elf) {
51 return -1;
52 }
53 elf_assert(elf->e_magic == ELF_MAGIC);
54 if (elf->e_kind != ELF_K_ELF) {
55 seterr(ERROR_NOTELF);
56 return -1;
57 }
58 if (!elf->e_ehdr && !_elf_cook(elf)) {
59 return -1;
60 }
61 if ((scn = elf->e_scn_n)) {
62 num = scn->s_index + 1;
63 }
64 if (resultp) {
65 *resultp = num;
66 }
67 return 0;
68 }
69
70 int
elf_getshdrstrndx(Elf * elf,size_t * resultp)71 elf_getshdrstrndx(Elf *elf, size_t *resultp) {
72 size_t num = 0;
73 size_t dummy;
74 Elf_Scn *scn;
75
76 if (!elf) {
77 return -1;
78 }
79 elf_assert(elf->e_magic == ELF_MAGIC);
80 if (resultp == NULL) {
81 resultp = &dummy; /* handle NULL pointer gracefully */
82 }
83 if (elf->e_kind != ELF_K_ELF) {
84 seterr(ERROR_NOTELF);
85 return -1;
86 }
87 if (!elf->e_ehdr && !_elf_cook(elf)) {
88 return -1;
89 }
90 if (elf->e_class == ELFCLASS32) {
91 num = ((Elf32_Ehdr*)elf->e_ehdr)->e_shstrndx;
92 }
93 #if __LIBELF64
94 else if (elf->e_class == ELFCLASS64) {
95 num = ((Elf64_Ehdr*)elf->e_ehdr)->e_shstrndx;
96 }
97 #endif /* __LIBELF64 */
98 else {
99 if (valid_class(elf->e_class)) {
100 seterr(ERROR_UNIMPLEMENTED);
101 }
102 else {
103 seterr(ERROR_UNKNOWN_CLASS);
104 }
105 return -1;
106 }
107 if (num != SHN_XINDEX) {
108 *resultp = num;
109 return 0;
110 }
111 /*
112 * look at first section header
113 */
114 if (!(scn = elf->e_scn_1)) {
115 seterr(ERROR_NOSUCHSCN);
116 return -1;
117 }
118 elf_assert(scn->s_magic == SCN_MAGIC);
119 #if __LIBELF64
120 if (elf->e_class == ELFCLASS64) {
121 *resultp = scn->s_shdr64.sh_link;
122 return 0;
123 }
124 #endif /* __LIBELF64 */
125 *resultp = scn->s_shdr32.sh_link;
126 return 0;
127 }
128
129 int
elf_getphnum(Elf * elf,size_t * resultp)130 elf_getphnum(Elf *elf, size_t *resultp) {
131 return elf_getphdrnum(elf, resultp) ? LIBELF_FAILURE : LIBELF_SUCCESS;
132 }
133
134 int
elf_getshnum(Elf * elf,size_t * resultp)135 elf_getshnum(Elf *elf, size_t *resultp) {
136 return elf_getshdrnum(elf, resultp) ? LIBELF_FAILURE : LIBELF_SUCCESS;
137 }
138
139 int
elf_getshstrndx(Elf * elf,size_t * resultp)140 elf_getshstrndx(Elf *elf, size_t *resultp) {
141 return elf_getshdrstrndx(elf, resultp) ? LIBELF_FAILURE : LIBELF_SUCCESS;
142 }
143
144 int
elfx_update_shstrndx(Elf * elf,size_t value)145 elfx_update_shstrndx(Elf *elf, size_t value) {
146 size_t extvalue = 0;
147 Elf_Scn *scn;
148
149 if (!elf) {
150 return LIBELF_FAILURE;
151 }
152 elf_assert(elf->e_magic == ELF_MAGIC);
153 if (value >= SHN_LORESERVE) {
154 extvalue = value;
155 value = SHN_XINDEX;
156 }
157 if (elf->e_kind != ELF_K_ELF) {
158 seterr(ERROR_NOTELF);
159 return LIBELF_FAILURE;
160 }
161 if (!elf->e_ehdr && !_elf_cook(elf)) {
162 return LIBELF_FAILURE;
163 }
164 if (!(scn = _elf_first_scn(elf))) {
165 return LIBELF_FAILURE;
166 }
167 elf_assert(scn->s_magic == SCN_MAGIC);
168 if (elf->e_class == ELFCLASS32) {
169 ((Elf32_Ehdr*)elf->e_ehdr)->e_shstrndx = value;
170 scn->s_shdr32.sh_link = extvalue;
171 }
172 #if __LIBELF64
173 else if (elf->e_class == ELFCLASS64) {
174 ((Elf64_Ehdr*)elf->e_ehdr)->e_shstrndx = value;
175 scn->s_shdr64.sh_link = extvalue;
176 }
177 #endif /* __LIBELF64 */
178 else {
179 if (valid_class(elf->e_class)) {
180 seterr(ERROR_UNIMPLEMENTED);
181 }
182 else {
183 seterr(ERROR_UNKNOWN_CLASS);
184 }
185 return LIBELF_FAILURE;
186 }
187 elf->e_ehdr_flags |= ELF_F_DIRTY;
188 scn->s_shdr_flags |= ELF_F_DIRTY;
189 return LIBELF_SUCCESS;
190 }
191