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/cdefs.h>
28 #include <sys/queue.h>
40 ELFTC_VCSID("$Id: elf_scn.c 3147 2015-02-15 18:45:23Z emaste $");
43 * Load an ELF section table and create a list of Elf_Scn structures.
46 _libelf_load_section_headers(Elf *e, void *ehdr)
55 int (*xlator)(unsigned char *_d, size_t _dsz, unsigned char *_s,
56 size_t _c, int _swap);
60 assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0);
62 #define CHECK_EHDR(E,EH) do { \
63 if (shoff > e->e_rawsize || \
64 fsz != (EH)->e_shentsize || \
65 shnum > SIZE_MAX / fsz || \
66 fsz * shnum > e->e_rawsize - shoff) { \
67 LIBELF_SET_ERROR(HEADER, 0); \
73 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1);
76 shnum = e->e_u.e_elf.e_nscn;
78 if (ec == ELFCLASS32) {
79 eh32 = (Elf32_Ehdr *) ehdr;
80 shoff = (uint64_t) eh32->e_shoff;
83 eh64 = (Elf64_Ehdr *) ehdr;
84 shoff = eh64->e_shoff;
88 xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
90 swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder);
91 src = e->e_rawfile + shoff;
94 * If the file is using extended numbering then section #0
95 * would have already been read in.
99 if (!STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
100 assert(STAILQ_FIRST(&e->e_u.e_elf.e_scn) ==
101 STAILQ_LAST(&e->e_u.e_elf.e_scn, _Elf_Scn, s_next));
107 for (; i < shnum; i++, src += fsz) {
108 if ((scn = _libelf_allocate_scn(e, i)) == NULL)
111 (*xlator)((unsigned char *) &scn->s_shdr, sizeof(scn->s_shdr),
112 src, (size_t) 1, swapbytes);
114 if (ec == ELFCLASS32) {
115 scn->s_offset = scn->s_rawoff =
116 scn->s_shdr.s_shdr32.sh_offset;
117 scn->s_size = scn->s_shdr.s_shdr32.sh_size;
119 scn->s_offset = scn->s_rawoff =
120 scn->s_shdr.s_shdr64.sh_offset;
121 scn->s_size = scn->s_shdr.s_shdr64.sh_size;
125 e->e_flags |= LIBELF_F_SHDRS_LOADED;
132 elf_getscn(Elf *e, size_t index)
138 if (e == NULL || e->e_kind != ELF_K_ELF ||
139 ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
140 LIBELF_SET_ERROR(ARGUMENT, 0);
144 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
147 if (e->e_cmd != ELF_C_WRITE &&
148 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
149 _libelf_load_section_headers(e, ehdr) == 0)
152 STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next)
153 if (s->s_ndx == index)
156 LIBELF_SET_ERROR(ARGUMENT, 0);
161 elf_ndxscn(Elf_Scn *s)
164 LIBELF_SET_ERROR(ARGUMENT, 0);
177 if (e == NULL || e->e_kind != ELF_K_ELF) {
178 LIBELF_SET_ERROR(ARGUMENT, 0);
182 if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) {
183 LIBELF_SET_ERROR(CLASS, 0);
187 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
191 * The application may be asking for a new section descriptor
192 * on an ELF object opened with ELF_C_RDWR or ELF_C_READ. We
193 * need to bring in the existing section information before
194 * appending a new one to the list.
196 * Per the ELF(3) API, an application is allowed to open a
197 * file using ELF_C_READ, mess with its internal structure and
198 * use elf_update(...,ELF_C_NULL) to compute its new layout.
200 if (e->e_cmd != ELF_C_WRITE &&
201 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
202 _libelf_load_section_headers(e, ehdr) == 0)
205 if (STAILQ_EMPTY(&e->e_u.e_elf.e_scn)) {
206 assert(e->e_u.e_elf.e_nscn == 0);
207 if ((scn = _libelf_allocate_scn(e, (size_t) SHN_UNDEF)) ==
210 e->e_u.e_elf.e_nscn++;
213 assert(e->e_u.e_elf.e_nscn > 0);
215 if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL)
218 e->e_u.e_elf.e_nscn++;
220 (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY);
226 elf_nextscn(Elf *e, Elf_Scn *s)
228 if (e == NULL || (e->e_kind != ELF_K_ELF) ||
229 (s && s->s_elf != e)) {
230 LIBELF_SET_ERROR(ARGUMENT, 0);
234 return (s == NULL ? elf_getscn(e, (size_t) 1) :
235 STAILQ_NEXT(s, s_next));