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("$FreeBSD$");
40 * Load an ELF section table and create a list of Elf_Scn structures.
43 _libelf_load_scn(Elf *e, void *ehdr)
52 int (*xlator)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
56 assert((e->e_flags & LIBELF_F_SHDRS_LOADED) == 0);
58 #define CHECK_EHDR(E,EH) do { \
59 if (shoff > e->e_rawsize || \
60 fsz != (EH)->e_shentsize || \
61 shnum > SIZE_MAX / fsz || \
62 fsz * shnum > e->e_rawsize - shoff) { \
63 LIBELF_SET_ERROR(HEADER, 0); \
69 fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, (size_t) 1);
72 shnum = e->e_u.e_elf.e_nscn;
74 if (ec == ELFCLASS32) {
75 eh32 = (Elf32_Ehdr *) ehdr;
76 shoff = (uint64_t) eh32->e_shoff;
79 eh64 = (Elf64_Ehdr *) ehdr;
80 shoff = eh64->e_shoff;
84 xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
86 swapbytes = e->e_byteorder != LIBELF_PRIVATE(byteorder);
87 src = e->e_rawfile + shoff;
90 * If the file is using extended numbering then section #0
91 * would have already been read in.
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));
103 for (; i < shnum; i++, src += fsz) {
104 if ((scn = _libelf_allocate_scn(e, i)) == NULL)
107 (*xlator)((char *) &scn->s_shdr, sizeof(scn->s_shdr), src,
108 (size_t) 1, swapbytes);
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;
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;
121 e->e_flags |= LIBELF_F_SHDRS_LOADED;
128 elf_getscn(Elf *e, size_t index)
134 if (e == NULL || e->e_kind != ELF_K_ELF ||
135 ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64)) {
136 LIBELF_SET_ERROR(ARGUMENT, 0);
140 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
143 if (e->e_cmd != ELF_C_WRITE &&
144 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
145 _libelf_load_scn(e, ehdr) == 0)
148 STAILQ_FOREACH(s, &e->e_u.e_elf.e_scn, s_next)
149 if (s->s_ndx == index)
152 LIBELF_SET_ERROR(ARGUMENT, 0);
157 elf_ndxscn(Elf_Scn *s)
160 LIBELF_SET_ERROR(ARGUMENT, 0);
173 if (e == NULL || e->e_kind != ELF_K_ELF) {
174 LIBELF_SET_ERROR(ARGUMENT, 0);
178 if ((ec = e->e_class) != ELFCLASS32 && ec != ELFCLASS64) {
179 LIBELF_SET_ERROR(CLASS, 0);
183 if ((ehdr = _libelf_ehdr(e, ec, 0)) == NULL)
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.
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.
196 if (e->e_cmd != ELF_C_WRITE &&
197 (e->e_flags & LIBELF_F_SHDRS_LOADED) == 0 &&
198 _libelf_load_scn(e, ehdr) == 0)
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)) ==
206 e->e_u.e_elf.e_nscn++;
209 assert(e->e_u.e_elf.e_nscn > 0);
211 if ((scn = _libelf_allocate_scn(e, e->e_u.e_elf.e_nscn)) == NULL)
214 e->e_u.e_elf.e_nscn++;
216 (void) elf_flagscn(scn, ELF_C_SET, ELF_F_DIRTY);
222 elf_nextscn(Elf *e, Elf_Scn *s)
224 if (e == NULL || (e->e_kind != ELF_K_ELF) ||
225 (s && s->s_elf != e)) {
226 LIBELF_SET_ERROR(ARGUMENT, 0);
230 return (s == NULL ? elf_getscn(e, (size_t) 1) :
231 STAILQ_NEXT(s, s_next));