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("$FreeBSD$");
29
30 #include <assert.h>
31 #include <errno.h>
32 #include <libelf.h>
33 #include <stdlib.h>
34
35 #include "_libelf.h"
36
37
38 Elf_Data *
elf_getdata(Elf_Scn * s,Elf_Data * d)39 elf_getdata(Elf_Scn *s, Elf_Data *d)
40 {
41 Elf *e;
42 size_t fsz, msz, count;
43 int elfclass, elftype;
44 unsigned int sh_type;
45 uint64_t sh_align, sh_offset, sh_size;
46 int (*xlate)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
47
48 if (s == NULL || (e = s->s_elf) == NULL || e->e_kind != ELF_K_ELF ||
49 (d != NULL && s != d->d_scn)) {
50 LIBELF_SET_ERROR(ARGUMENT, 0);
51 return (NULL);
52 }
53
54 if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL)
55 return (d);
56
57 if (d != NULL)
58 return (STAILQ_NEXT(d, d_next));
59
60 if (e->e_rawfile == NULL) {
61 LIBELF_SET_ERROR(SEQUENCE, 0);
62 return (NULL);
63 }
64
65 elfclass = e->e_class;
66
67 assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
68
69 if (elfclass == ELFCLASS32) {
70 sh_type = s->s_shdr.s_shdr32.sh_type;
71 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
72 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
73 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
74 } else {
75 sh_type = s->s_shdr.s_shdr64.sh_type;
76 sh_offset = s->s_shdr.s_shdr64.sh_offset;
77 sh_size = s->s_shdr.s_shdr64.sh_size;
78 sh_align = s->s_shdr.s_shdr64.sh_addralign;
79 }
80
81 if (sh_type == SHT_NULL) {
82 LIBELF_SET_ERROR(SECTION, 0);
83 return (NULL);
84 }
85
86 if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
87 elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
88 sh_offset + sh_size > (uint64_t) e->e_rawsize)) {
89 LIBELF_SET_ERROR(SECTION, 0);
90 return (NULL);
91 }
92
93 if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
94 (elftype, (size_t) 1, e->e_version)) == 0) {
95 LIBELF_SET_ERROR(UNIMPL, 0);
96 return (NULL);
97 }
98
99 if (sh_size % fsz) {
100 LIBELF_SET_ERROR(SECTION, 0);
101 return (NULL);
102 }
103
104 count = sh_size / fsz;
105
106 msz = _libelf_msize(elftype, elfclass, e->e_version);
107
108 assert(msz > 0);
109
110 if ((d = _libelf_allocate_data(s)) == NULL)
111 return (NULL);
112
113 d->d_buf = NULL;
114 d->d_off = 0;
115 d->d_align = sh_align;
116 d->d_size = msz * count;
117 d->d_type = elftype;
118 d->d_version = e->e_version;
119
120 if (sh_type == SHT_NOBITS || sh_size == 0) {
121 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
122 return (d);
123 }
124
125 if ((d->d_buf = malloc(msz*count)) == NULL) {
126 (void) _libelf_release_data(d);
127 LIBELF_SET_ERROR(RESOURCE, 0);
128 return (NULL);
129 }
130
131 d->d_flags |= LIBELF_F_MALLOCED;
132
133 xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass);
134 if (!(*xlate)(d->d_buf, d->d_size, e->e_rawfile + sh_offset, count,
135 e->e_byteorder != LIBELF_PRIVATE(byteorder))) {
136 _libelf_release_data(d);
137 LIBELF_SET_ERROR(DATA, 0);
138 return (NULL);
139 }
140
141 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
142
143 return (d);
144 }
145
146 Elf_Data *
elf_newdata(Elf_Scn * s)147 elf_newdata(Elf_Scn *s)
148 {
149 Elf *e;
150 Elf_Data *d;
151
152 if (s == NULL || (e = s->s_elf) == NULL ||
153 e->e_kind != ELF_K_ELF) {
154 LIBELF_SET_ERROR(ARGUMENT, 0);
155 return (NULL);
156 }
157
158 /*
159 * elf_newdata() has to append a data descriptor, so
160 * bring in existing section data if not already present.
161 */
162 if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
163 if (elf_getdata(s, NULL) == NULL)
164 return (NULL);
165
166 if ((d = _libelf_allocate_data(s)) == NULL)
167 return (NULL);
168
169 STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
170
171 d->d_align = 1;
172 d->d_buf = NULL;
173 d->d_off = (uint64_t) ~0;
174 d->d_size = 0;
175 d->d_type = ELF_T_BYTE;
176 d->d_version = LIBELF_PRIVATE(version);
177
178 (void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);
179
180 return (d);
181 }
182
183 /*
184 * Retrieve a data descriptor for raw (untranslated) data for section
185 * `s'.
186 */
187
188 Elf_Data *
elf_rawdata(Elf_Scn * s,Elf_Data * d)189 elf_rawdata(Elf_Scn *s, Elf_Data *d)
190 {
191 Elf *e;
192 int elf_class;
193 uint32_t sh_type;
194 uint64_t sh_align, sh_offset, sh_size;
195
196 if (s == NULL || (e = s->s_elf) == NULL ||
197 e->e_kind != ELF_K_ELF || e->e_rawfile == NULL) {
198 LIBELF_SET_ERROR(ARGUMENT, 0);
199 return (NULL);
200 }
201
202 if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
203 return (d);
204
205 if (d != NULL)
206 return (STAILQ_NEXT(d, d_next));
207
208 elf_class = e->e_class;
209
210 assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
211
212 if (elf_class == ELFCLASS32) {
213 sh_type = s->s_shdr.s_shdr32.sh_type;
214 sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
215 sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
216 sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
217 } else {
218 sh_type = s->s_shdr.s_shdr64.sh_type;
219 sh_offset = s->s_shdr.s_shdr64.sh_offset;
220 sh_size = s->s_shdr.s_shdr64.sh_size;
221 sh_align = s->s_shdr.s_shdr64.sh_addralign;
222 }
223
224 if (sh_type == SHT_NULL) {
225 LIBELF_SET_ERROR(SECTION, 0);
226 return (NULL);
227 }
228
229 if ((d = _libelf_allocate_data(s)) == NULL)
230 return (NULL);
231
232 d->d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
233 e->e_rawfile + sh_offset;
234 d->d_off = 0;
235 d->d_align = sh_align;
236 d->d_size = sh_size;
237 d->d_type = ELF_T_BYTE;
238 d->d_version = e->e_version;
239
240 STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
241
242 return (d);
243 }
244