1 | /*- |
---|
2 | * Copyright (c) 2006,2008-2010 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 | #include <sys/queue.h> |
---|
29 | |
---|
30 | #include <assert.h> |
---|
31 | #include <errno.h> |
---|
32 | #include <gelf.h> |
---|
33 | #include <libelf.h> |
---|
34 | #include <stddef.h> |
---|
35 | #include <stdlib.h> |
---|
36 | |
---|
37 | #include "_libelf.h" |
---|
38 | |
---|
39 | LIBELF_VCSID("$Id: elf_scn.c 1077 2010-08-09 15:37:40Z jkoshy $"); |
---|
40 | |
---|
41 | /* |
---|
42 | * Load an ELF section table and create a list of Elf_Scn structures. |
---|
43 | */ |
---|
44 | int |
---|
45 | _libelf_load_section_headers(Elf *e, void *ehdr) |
---|
46 | { |
---|
47 | int ec, swapbytes; |
---|
48 | size_t fsz, i, shnum; |
---|
49 | uint64_t shoff; |
---|
50 | char *src; |
---|
51 | Elf32_Ehdr *eh32; |
---|
52 | Elf64_Ehdr *eh64; |
---|
53 | Elf_Scn *scn; |
---|
54 | int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap); |
---|
55 | |
---|
56 | assert(e != NULL); |
---|
57 | assert(ehdr != NULL); |
---|
58 | assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0); |
---|
59 | |
---|
60 | #define CHECK_EHDR(E,EH) do { \ |
---|
61 | if (fsz != (EH)->e_shentsize || \ |
---|
62 | shoff + fsz * shnum > e->e_rawsize) { \ |
---|
63 | LIBELF_SET_ERROR(HEADER, 0); \ |
---|
64 | return (0); \ |
---|
65 | } \ |
---|
66 | } while (0) |
---|
67 | |
---|
68 | ec = e->e_class; |
---|
69 | fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1); |
---|
70 | assert(fsz > 0); |
---|
71 | |
---|
72 | shnum = e->e_u.e_elf.e_nscn; |
---|
73 | |
---|
74 | if (ec == ELFCLASS32) { |
---|
75 | eh32 = (Elf32_Ehdr *) ehdr; |
---|
76 | shoff = (uint64_t) eh32->e_shoff; |
---|
77 | CHECK_EHDR(e, eh32); |
---|
78 | } else { |
---|
79 | eh64 = (Elf64_Ehdr *) ehdr; |
---|
80 | shoff = eh64->e_shoff; |
---|
81 | CHECK_EHDR(e, eh64); |
---|
82 | } |
---|
83 | |
---|
84 | xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec); |
---|
85 | |
---|
86 | swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder); |
---|
87 | src = e->e_rawfile + shoff; |
---|
88 | |
---|
89 | /* |
---|
90 | * If the file is using extended numbering then section #0 |
---|
91 | * would have already been read in. |
---|
92 | */ |
---|
93 | |
---|
94 | i = 0; |
---|
95 | if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { |
---|
96 | assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) == |
---|
97 | STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next)); |
---|
98 | |
---|
99 | i = 1; |
---|
100 | src += fsz; |
---|
101 | } |
---|
102 | |
---|
103 | for (; i < shnum; i++, src += fsz) { |
---|
104 | if ((scn = _libelf_allocate_scn(e, i)) == NULL) |
---|
105 | return (0); |
---|
106 | |
---|
107 | (*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr), src, |
---|
108 | (size_t) 1, swapbytes); |
---|
109 | |
---|
110 | if (ec == ELFCLASS32) { |
---|
111 | scn->s_offset = scn->s_rawoff = |
---|
112 | scn->s_shdr.s_shdr32.sh_offset; |
---|
113 | scn->s_size = scn->s_shdr.s_shdr32.sh_size; |
---|
114 | } else { |
---|
115 | scn->s_offset = scn->s_rawoff = |
---|
116 | scn->s_shdr.s_shdr64.sh_offset; |
---|
117 | scn->s_size = scn->s_shdr.s_shdr64.sh_size; |
---|
118 | } |
---|
119 | } |
---|
120 | |
---|
121 | e->e_flags |= LIBELF_F_SHDRS_LOADED; |
---|
122 | |
---|
123 | return (1); |
---|
124 | } |
---|
125 | |
---|
126 | |
---|
127 | Elf_Scn * |
---|
128 | elf_getscn(Elf *e, size_t index) |
---|
129 | { |
---|
130 | int ec; |
---|
131 | void *ehdr; |
---|
132 | Elf_Scn *s; |
---|
133 | |
---|
134 | if (e == NULL || e->e_kind != ELF_K_ELF || |
---|
135 | ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) { |
---|
136 | LIBELF_SET_ERROR(ARGUMENT, 0); |
---|
137 | return (NULL); |
---|
138 | } |
---|
139 | |
---|
140 | if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) |
---|
141 | return (NULL); |
---|
142 | |
---|
143 | if (e->e_cmd != ELF_C_WRITE && |
---|
144 | (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && |
---|
145 | _libelf_load_section_headers(e, ehdr) == 0) |
---|
146 | return (NULL); |
---|
147 | |
---|
148 | STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next) |
---|
149 | if (s->s_ndx == index) |
---|
150 | return (s); |
---|
151 | |
---|
152 | LIBELF_SET_ERROR(ARGUMENT, 0); |
---|
153 | return (NULL); |
---|
154 | } |
---|
155 | |
---|
156 | size_t |
---|
157 | elf_ndxscn(Elf_Scn *s) |
---|
158 | { |
---|
159 | if (s == NULL) { |
---|
160 | LIBELF_SET_ERROR(ARGUMENT, 0); |
---|
161 | return (SHN_UNDEF); |
---|
162 | } |
---|
163 | return (s->s_ndx); |
---|
164 | } |
---|
165 | |
---|
166 | Elf_Scn * |
---|
167 | elf_newscn(Elf *e) |
---|
168 | { |
---|
169 | int ec; |
---|
170 | void *ehdr; |
---|
171 | Elf_Scn *scn; |
---|
172 | |
---|
173 | if (e == NULL || e->e_kind != ELF_K_ELF) { |
---|
174 | LIBELF_SET_ERROR(ARGUMENT, 0); |
---|
175 | return (NULL); |
---|
176 | } |
---|
177 | |
---|
178 | if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) { |
---|
179 | LIBELF_SET_ERROR(CLASS, 0); |
---|
180 | return (NULL); |
---|
181 | } |
---|
182 | |
---|
183 | if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL) |
---|
184 | return (NULL); |
---|
185 | |
---|
186 | /* |
---|
187 | * The application may be asking for a new section descriptor |
---|
188 | * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We |
---|
189 | * need to bring in the existing section information before |
---|
190 | * appending a new one to the list. |
---|
191 | * |
---|
192 | * Per the ELF(3) API, an application is allowed to open a |
---|
193 | * file using ELF_C_READ, mess with its internal structure and |
---|
194 | * use elf_update(...,ELF_C_NULL) to compute its new layout. |
---|
195 | */ |
---|
196 | if (e->e_cmd != ELF_C_WRITE && |
---|
197 | (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 && |
---|
198 | _libelf_load_section_headers(e, ehdr) == 0) |
---|
199 | return (NULL); |
---|
200 | |
---|
201 | if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) { |
---|
202 | assert(e->e_u.e_elf.e_nscn == 0); |
---|
203 | if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) == |
---|
204 | NULL) |
---|
205 | return (NULL); |
---|
206 | e->e_u.e_elf.e_nscn++; |
---|
207 | } |
---|
208 | |
---|
209 | assert(e->e_u.e_elf.e_nscn > 0); |
---|
210 | |
---|
211 | if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL) |
---|
212 | return (NULL); |
---|
213 | |
---|
214 | e->e_u.e_elf.e_nscn++; |
---|
215 | |
---|
216 | (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY); |
---|
217 | |
---|
218 | return (scn); |
---|
219 | } |
---|
220 | |
---|
221 | Elf_Scn * |
---|
222 | elf_nextscn(Elf *e, Elf_Scn *s) |
---|
223 | { |
---|
224 | if (e == NULL || (e->e_kind != ELF_K_ELF) || |
---|
225 | (s && s->s_elf != e)) { |
---|
226 | LIBELF_SET_ERROR(ARGUMENT, 0); |
---|
227 | return (NULL); |
---|
228 | } |
---|
229 | |
---|
230 | return (s == NULL ? elf_getscn(e, (size_t) 1) : |
---|
231 | STAILQ_NEXT(s, s_next)); |
---|
232 | } |
---|