2 * Copyright (c) 2006,2008-2010 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
27 #include <sys/queue.h>
39 ELFTC_VCSID("$Id: elf_scn.c 3177 2015-03-30 18:19:41Z emaste $");
42 * Load an ELF section table and create a list of Elf_Scn structures.
45 _libelf_load_section_headers(Elf *e, void *ehdr)
54 int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s,
55 size_t _c, int _swap);
59 assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0);
61 #define CHECK_EHDR(E,EH) do { \
62 if (shoff > e->e_rawsize || \
63 fsz != (EH)->e_shentsize || \
64 shnum > SIZE_MAX / fsz || \
65 fsz * shnum > e->e_rawsize - shoff) { \
66 LIBELF_SET_ERROR(HEADER, 0); \
72 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1);
75 shnum = e->e_u.e_elf.e_nscn;
77 if (ec == ELFCLASS32) {
78 eh32 = (Elf32_Ehdr *) ehdr;
79 shoff = (uint64_t) eh32->e_shoff;
82 eh64 = (Elf64_Ehdr *) ehdr;
83 shoff = eh64->e_shoff;
87 xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
89 swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder);
90 src = e->e_rawfile + shoff;
93 * If the file is using extended numbering then section #0
94 * would have already been read in.
98 if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
99 assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) ==
100 STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next));
106 for (; i < shnum; i++, src += fsz) {
107 if ((scn = _libelf_allocate_scn(e, i)) == NULL)
110 (*xlator)((unsigned char *) &scn->s_shdr, sizeof(scn->s_shdr),
111 src, (size_t) 1, swapbytes);
113 if (ec == ELFCLASS32) {
114 scn->s_offset = scn->s_rawoff =
115 scn->s_shdr.s_shdr32.sh_offset;
116 scn->s_size = scn->s_shdr.s_shdr32.sh_size;
118 scn->s_offset = scn->s_rawoff =
119 scn->s_shdr.s_shdr64.sh_offset;
120 scn->s_size = scn->s_shdr.s_shdr64.sh_size;
124 e->e_flags |= LIBELF_F_SHDRS_LOADED;
131 elf_getscn(Elf *e, size_t index)
137 if (e == NULL || e->e_kind != ELF_K_ELF ||
138 ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
139 LIBELF_SET_ERROR(ARGUMENT, 0);
143 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
146 if (e->e_cmd != ELF_C_WRITE &&
147 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
148 _libelf_load_section_headers(e, ehdr) == 0)
151 STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next)
152 if (s->s_ndx == index)
155 LIBELF_SET_ERROR(ARGUMENT, 0);
160 elf_ndxscn(Elf_Scn *s)
163 LIBELF_SET_ERROR(ARGUMENT, 0);
176 if (e == NULL || e->e_kind != ELF_K_ELF) {
177 LIBELF_SET_ERROR(ARGUMENT, 0);
181 if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) {
182 LIBELF_SET_ERROR(CLASS, 0);
186 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
190 * The application may be asking for a new section descriptor
191 * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We
192 * need to bring in the existing section information before
193 * appending a new one to the list.
195 * Per the ELF(3) API, an application is allowed to open a
196 * file using ELF_C_READ, mess with its internal structure and
197 * use elf_update(...,ELF_C_NULL) to compute its new layout.
199 if (e->e_cmd != ELF_C_WRITE &&
200 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
201 _libelf_load_section_headers(e, ehdr) == 0)
204 if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
205 assert(e->e_u.e_elf.e_nscn == 0);
206 if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) ==
209 e->e_u.e_elf.e_nscn++;
212 assert(e->e_u.e_elf.e_nscn > 0);
214 if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL)
217 e->e_u.e_elf.e_nscn++;
219 (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY);
225 elf_nextscn(Elf *e, Elf_Scn *s)
227 if (e == NULL || (e->e_kind != ELF_K_ELF) ||
228 (s && s->s_elf != e)) {
229 LIBELF_SET_ERROR(ARGUMENT, 0);
233 return (s == NULL ? elf_getscn(e, (size_t) 1) :
234 STAILQ_NEXT(s, s_next));