2 * Copyright (c) 2006 Joseph Koshy
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
38 * Load an ELF section table and create a list of Elf_Scn structures.
41 _libelf_load_scn(Elf
*e
, void *ehdr
)
50 void (*xlator
)(char *_d
, char *_s
, size_t _c
, int _swap
);
54 assert((e
->e_flags
& LIBELF_F_SHDRS_LOADED
) == 0);
56 #define CHECK_EHDR(E,EH) do { \
57 if (fsz != (EH)->e_shentsize || \
58 shoff + fsz * shnum > e->e_rawsize) { \
59 LIBELF_SET_ERROR(HEADER, 0); \
65 fsz
= _libelf_fsize(ELF_T_SHDR
, ec
, e
->e_version
, (size_t) 1);
68 shnum
= e
->e_u
.e_elf
.e_nscn
;
70 if (ec
== ELFCLASS32
) {
71 eh32
= (Elf32_Ehdr
*) ehdr
;
72 shoff
= (uint64_t) eh32
->e_shoff
;
75 eh64
= (Elf64_Ehdr
*) ehdr
;
76 shoff
= eh64
->e_shoff
;
80 xlator
= _libelf_get_translator(ELF_T_SHDR
, ELF_TOMEMORY
, ec
);
82 swapbytes
= e
->e_byteorder
!= LIBELF_PRIVATE(byteorder
);
83 src
= e
->e_rawfile
+ shoff
;
86 * If the file is using extended numbering then section #0
87 * would have already been read in.
91 if (!STAILQ_EMPTY(&e
->e_u
.e_elf
.e_scn
)) {
92 assert(STAILQ_FIRST(&e
->e_u
.e_elf
.e_scn
) ==
93 STAILQ_LAST(&e
->e_u
.e_elf
.e_scn
, _Elf_Scn
, s_next
));
99 for (; i
< shnum
; i
++, src
+= fsz
) {
100 if ((scn
= _libelf_allocate_scn(e
, i
)) == NULL
)
103 (*xlator
)((char *) &scn
->s_shdr
, src
, (size_t) 1, swapbytes
);
105 if (ec
== ELFCLASS32
) {
106 scn
->s_offset
= scn
->s_rawoff
=
107 scn
->s_shdr
.s_shdr32
.sh_offset
;
108 scn
->s_size
= scn
->s_shdr
.s_shdr32
.sh_size
;
110 scn
->s_offset
= scn
->s_rawoff
=
111 scn
->s_shdr
.s_shdr64
.sh_offset
;
112 scn
->s_size
= scn
->s_shdr
.s_shdr64
.sh_size
;
116 e
->e_flags
|= LIBELF_F_SHDRS_LOADED
;
123 elf_getscn(Elf
*e
, size_t index
)
129 if (e
== NULL
|| e
->e_kind
!= ELF_K_ELF
||
130 ((ec
= e
->e_class
) != ELFCLASS32
&& ec
!= ELFCLASS64
)) {
131 LIBELF_SET_ERROR(ARGUMENT
, 0);
135 if ((ehdr
= _libelf_ehdr(e
, ec
, 0)) == NULL
)
138 if (e
->e_cmd
!= ELF_C_WRITE
&&
139 (e
->e_flags
& LIBELF_F_SHDRS_LOADED
) == 0 &&
140 _libelf_load_scn(e
, ehdr
) == 0)
143 STAILQ_FOREACH(s
, &e
->e_u
.e_elf
.e_scn
, s_next
)
144 if (s
->s_ndx
== index
)
147 LIBELF_SET_ERROR(ARGUMENT
, 0);
152 elf_ndxscn(Elf_Scn
*s
)
155 LIBELF_SET_ERROR(ARGUMENT
, 0);
168 if (e
== NULL
|| e
->e_kind
!= ELF_K_ELF
) {
169 LIBELF_SET_ERROR(ARGUMENT
, 0);
173 if ((ec
= e
->e_class
) != ELFCLASS32
&& ec
!= ELFCLASS64
) {
174 LIBELF_SET_ERROR(CLASS
, 0);
178 if ((ehdr
= _libelf_ehdr(e
, ec
, 0)) == NULL
)
182 * The application may be asking for a new section descriptor
183 * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We
184 * need to bring in the existing section information before
185 * appending a new one to the list.
187 * Per the ELF(3) API, an application is allowed to open a
188 * file using ELF_C_READ, mess with its internal structure and
189 * use elf_update(...,ELF_C_NULL) to compute its new layout.
191 if (e
->e_cmd
!= ELF_C_WRITE
&&
192 (e
->e_flags
& LIBELF_F_SHDRS_LOADED
) == 0 &&
193 _libelf_load_scn(e
, ehdr
) == 0)
196 if (STAILQ_EMPTY(&e
->e_u
.e_elf
.e_scn
)) {
197 assert(e
->e_u
.e_elf
.e_nscn
== 0);
198 if ((scn
= _libelf_allocate_scn(e
, (size_t) SHN_UNDEF
)) ==
201 e
->e_u
.e_elf
.e_nscn
++;
204 assert(e
->e_u
.e_elf
.e_nscn
> 0);
206 if ((scn
= _libelf_allocate_scn(e
, e
->e_u
.e_elf
.e_nscn
)) == NULL
)
209 e
->e_u
.e_elf
.e_nscn
++;
211 (void) elf_flagscn(scn
, ELF_C_SET
, ELF_F_DIRTY
);
217 elf_nextscn(Elf
*e
, Elf_Scn
*s
)
219 if (e
== NULL
|| (e
->e_kind
!= ELF_K_ELF
) ||
220 (s
&& s
->s_elf
!= e
)) {
221 LIBELF_SET_ERROR(ARGUMENT
, 0);
225 return (s
== NULL
? elf_getscn(e
, (size_t) 1) :
226 STAILQ_NEXT(s
, s_next
));