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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
39 * Load an ELF section table and create a list of Elf_Scn structures.
42 _libelf_load_scn(Elf *e, void *ehdr)
51 int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
55 assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0);
57 #define CHECK_EHDR(E,EH) do { \
58 if (fsz != (EH)->e_shentsize || \
59 shoff + fsz * shnum > e->e_rawsize) { \
60 LIBELF_SET_ERROR(HEADER, 0); \
66 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1);
69 shnum = e->e_u.e_elf.e_nscn;
71 if (ec == ELFCLASS32) {
72 eh32 = (Elf32_Ehdr *) ehdr;
73 shoff = (uint64_t) eh32->e_shoff;
76 eh64 = (Elf64_Ehdr *) ehdr;
77 shoff = eh64->e_shoff;
81 xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
83 swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder);
84 src = e->e_rawfile + shoff;
87 * If the file is using extended numbering then section #0
88 * would have already been read in.
92 if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
93 assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) ==
94 STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next));
100 for (; i < shnum; i++, src += fsz) {
101 if ((scn = _libelf_allocate_scn(e, i)) == NULL)
104 (*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr), src,
105 (size_t) 1, swapbytes);
107 if (ec == ELFCLASS32) {
108 scn->s_offset = scn->s_rawoff =
109 scn->s_shdr.s_shdr32.sh_offset;
110 scn->s_size = scn->s_shdr.s_shdr32.sh_size;
112 scn->s_offset = scn->s_rawoff =
113 scn->s_shdr.s_shdr64.sh_offset;
114 scn->s_size = scn->s_shdr.s_shdr64.sh_size;
118 e->e_flags |= LIBELF_F_SHDRS_LOADED;
125 elf_getscn(Elf *e, size_t index)
131 if (e == NULL || e->e_kind != ELF_K_ELF ||
132 ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
133 LIBELF_SET_ERROR(ARGUMENT, 0);
137 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
140 if (e->e_cmd != ELF_C_WRITE &&
141 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
142 _libelf_load_scn(e, ehdr) == 0)
145 STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next)
146 if (s->s_ndx == index)
149 LIBELF_SET_ERROR(ARGUMENT, 0);
154 elf_ndxscn(Elf_Scn *s)
157 LIBELF_SET_ERROR(ARGUMENT, 0);
170 if (e == NULL || e->e_kind != ELF_K_ELF) {
171 LIBELF_SET_ERROR(ARGUMENT, 0);
175 if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) {
176 LIBELF_SET_ERROR(CLASS, 0);
180 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
184 * The application may be asking for a new section descriptor
185 * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We
186 * need to bring in the existing section information before
187 * appending a new one to the list.
189 * Per the ELF(3) API, an application is allowed to open a
190 * file using ELF_C_READ, mess with its internal structure and
191 * use elf_update(...,ELF_C_NULL) to compute its new layout.
193 if (e->e_cmd != ELF_C_WRITE &&
194 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
195 _libelf_load_scn(e, ehdr) == 0)
198 if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
199 assert(e->e_u.e_elf.e_nscn == 0);
200 if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) ==
203 e->e_u.e_elf.e_nscn++;
206 assert(e->e_u.e_elf.e_nscn > 0);
208 if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL)
211 e->e_u.e_elf.e_nscn++;
213 (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY);
219 elf_nextscn(Elf *e, Elf_Scn *s)
221 if (e == NULL || (e->e_kind != ELF_K_ELF) ||
222 (s && s->s_elf != e)) {
223 LIBELF_SET_ERROR(ARGUMENT, 0);
227 return (s == NULL ? elf_getscn(e, (size_t) 1) :
228 STAILQ_NEXT(s, s_next));