1 /* $NetBSD: elf_data.c,v 1.2 2014/03/09 16:58:04 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2006,2008,2011 Joseph Koshy
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #if HAVE_NBTOOL_CONFIG_H
30 # include "nbtool_config.h"
31 #endif
32
33 #include <assert.h>
34 #include <errno.h>
35 #include <libelf.h>
36 #include <stdlib.h>
37
38 #include "_libelf.h"
39
40 __RCSID("$NetBSD: elf_data.c,v 1.2 2014/03/09 16:58:04 christos Exp $");
41 ELFTC_VCSID("Id: elf_data.c 2921 2013-03-04 16:19:22Z jkoshy ");
42
43 Elf_Data *
elf_getdata(Elf_Scn * s,Elf_Data * ed)44 elf_getdata(Elf_Scn *s, Elf_Data *ed)
45 {
46 Elf *e;
47 unsigned int sh_type;
48 int elfclass, elftype;
49 size_t fsz, msz, count;
50 struct _Libelf_Data *d;
51 uint64_t sh_align, sh_offset, sh_size;
52 int (*xlate)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
53
54 d = (struct _Libelf_Data *) ed;
55
56 if (s == NULL || (e = s->s_elf) == NULL ||
57 (d != NULL && s != d->d_scn)) {
58 LIBELF_SET_ERROR(ARGUMENT, 0);
59 return (NULL);
60 }
61
62 assert(e->e_kind == ELF_K_ELF);
63
64 if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL)
65 return (&d->d_data);
66
67 if (d != NULL)
68 return (&STAILQ_NEXT(d, d_next)->d_data);
69
70 if (e->e_rawfile == NULL) {
71 /*
72 * In the ELF_C_WRITE case, there is no source that
73 * can provide data for the section.
74 */
75 LIBELF_SET_ERROR(ARGUMENT, 0);
76 return (NULL);
77 }
78
79 elfclass = e->e_class;
80
81 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
82
83 if (elfclass == ELFCLASS32) {
84 sh_type = s->s_shdr.s_shdr32.sh_type;
85 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
86 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
87 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
88 } else {
89 sh_type = s->s_shdr.s_shdr64.sh_type;
90 sh_offset = s->s_shdr.s_shdr64.sh_offset;
91 sh_size = s->s_shdr.s_shdr64.sh_size;
92 sh_align = s->s_shdr.s_shdr64.sh_addralign;
93 }
94
95 if (sh_type == SHT_NULL) {
96 LIBELF_SET_ERROR(SECTION, 0);
97 return (NULL);
98 }
99
100 if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
101 elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
102 sh_offset + sh_size > (uint64_t) e->e_rawsize)) {
103 LIBELF_SET_ERROR(SECTION, 0);
104 return (NULL);
105 }
106
107 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
108 (elftype, (size_t) 1, e->e_version)) == 0) {
109 LIBELF_SET_ERROR(UNIMPL, 0);
110 return (NULL);
111 }
112
113 if (sh_size % fsz) {
114 LIBELF_SET_ERROR(SECTION, 0);
115 return (NULL);
116 }
117
118 count = sh_size / fsz;
119
120 msz = _libelf_msize(elftype, elfclass, e->e_version);
121
122 assert(msz > 0);
123
124 if ((d = _libelf_allocate_data(s)) == NULL)
125 return (NULL);
126
127 d->d_data.d_buf = NULL;
128 d->d_data.d_off = 0;
129 d->d_data.d_align = sh_align;
130 d->d_data.d_size = msz * count;
131 d->d_data.d_type = elftype;
132 d->d_data.d_version = e->e_version;
133
134 if (sh_type == SHT_NOBITS || sh_size == 0) {
135 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
136 return (&d->d_data);
137 }
138
139 if ((d->d_data.d_buf = malloc(msz*count)) == NULL) {
140 (void) _libelf_release_data(d);
141 LIBELF_SET_ERROR(RESOURCE, 0);
142 return (NULL);
143 }
144
145 d->d_flags |= LIBELF_F_DATA_MALLOCED;
146
147 xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass);
148 if (!(*xlate)(d->d_data.d_buf, d->d_data.d_size,
149 e->e_rawfile + sh_offset, count,
150 e->e_byteorder != _libelf_host_byteorder())) {
151 _libelf_release_data(d);
152 LIBELF_SET_ERROR(DATA, 0);
153 return (NULL);
154 }
155
156 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
157
158 return (&d->d_data);
159 }
160
161 Elf_Data *
elf_newdata(Elf_Scn * s)162 elf_newdata(Elf_Scn *s)
163 {
164 Elf *e;
165 struct _Libelf_Data *d;
166
167 if (s == NULL || (e = s->s_elf) == NULL) {
168 LIBELF_SET_ERROR(ARGUMENT, 0);
169 return (NULL);
170 }
171
172 assert(e->e_kind == ELF_K_ELF);
173
174 /*
175 * elf_newdata() has to append a data descriptor, so
176 * bring in existing section data if not already present.
177 */
178 if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
179 if (elf_getdata(s, NULL) == NULL)
180 return (NULL);
181
182 if ((d = _libelf_allocate_data(s)) == NULL)
183 return (NULL);
184
185 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
186
187 d->d_data.d_align = 1;
188 d->d_data.d_buf = NULL;
189 d->d_data.d_off = (uint64_t) ~0;
190 d->d_data.d_size = 0;
191 d->d_data.d_type = ELF_T_BYTE;
192 d->d_data.d_version = LIBELF_PRIVATE(version);
193
194 (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);
195
196 return (&d->d_data);
197 }
198
199 /*
200 * Retrieve a data descriptor for raw (untranslated) data for section
201 * `s'.
202 */
203
204 Elf_Data *
elf_rawdata(Elf_Scn * s,Elf_Data * ed)205 elf_rawdata(Elf_Scn *s, Elf_Data *ed)
206 {
207 Elf *e;
208 int elf_class;
209 uint32_t sh_type;
210 struct _Libelf_Data *d;
211 uint64_t sh_align, sh_offset, sh_size;
212
213 if (s == NULL || (e = s->s_elf) == NULL || e->e_rawfile == NULL) {
214 LIBELF_SET_ERROR(ARGUMENT, 0);
215 return (NULL);
216 }
217
218 assert(e->e_kind == ELF_K_ELF);
219
220 d = (struct _Libelf_Data *) ed;
221
222 if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
223 return (&d->d_data);
224
225 if (d != NULL)
226 return (&STAILQ_NEXT(d, d_next)->d_data);
227
228 elf_class = e->e_class;
229
230 assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
231
232 if (elf_class == ELFCLASS32) {
233 sh_type = s->s_shdr.s_shdr32.sh_type;
234 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
235 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
236 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
237 } else {
238 sh_type = s->s_shdr.s_shdr64.sh_type;
239 sh_offset = s->s_shdr.s_shdr64.sh_offset;
240 sh_size = s->s_shdr.s_shdr64.sh_size;
241 sh_align = s->s_shdr.s_shdr64.sh_addralign;
242 }
243
244 if (sh_type == SHT_NULL) {
245 LIBELF_SET_ERROR(SECTION, 0);
246 return (NULL);
247 }
248
249 if ((d = _libelf_allocate_data(s)) == NULL)
250 return (NULL);
251
252 d->d_data.d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
253 e->e_rawfile + sh_offset;
254 d->d_data.d_off = 0;
255 d->d_data.d_align = sh_align;
256 d->d_data.d_size = sh_size;
257 d->d_data.d_type = ELF_T_BYTE;
258 d->d_data.d_version = e->e_version;
259
260 STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
261
262 return (&d->d_data);
263 }
264