freebsd-dev/lib/libelf/elf_data.c
Kai Wang 08a7f479dd For zero-sized sections, set the d_buf field of the Elf_Data
descriptor returned by `elf_rawdata()` to NULL.

Obtained from:	elftoolchain
2011-05-07 11:04:36 +00:00

240 lines
6.1 KiB
C

/*-
* Copyright (c) 2006 Joseph Koshy
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <assert.h>
#include <errno.h>
#include <libelf.h>
#include <stdlib.h>
#include "_libelf.h"
Elf_Data *
elf_getdata(Elf_Scn *s, Elf_Data *d)
{
Elf *e;
size_t fsz, msz, count;
int elfclass, elftype;
unsigned int sh_type;
uint64_t sh_align, sh_offset, sh_size;
int (*xlate)(char *_d, size_t _dsz, char *_s, size_t _c, int _swap);
if (s == NULL || (e = s->s_elf) == NULL || e->e_kind != ELF_K_ELF ||
(d != NULL && s != d->d_scn)) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
if (d == NULL && (d = STAILQ_FIRST(&s->s_data)) != NULL)
return (d);
if (d != NULL)
return (STAILQ_NEXT(d, d_next));
if (e->e_rawfile == NULL) {
LIBELF_SET_ERROR(SEQUENCE, 0);
return (NULL);
}
elfclass = e->e_class;
assert(elfclass == ELFCLASS32 || elfclass == ELFCLASS64);
if (elfclass == ELFCLASS32) {
sh_type = s->s_shdr.s_shdr32.sh_type;
sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
} else {
sh_type = s->s_shdr.s_shdr64.sh_type;
sh_offset = s->s_shdr.s_shdr64.sh_offset;
sh_size = s->s_shdr.s_shdr64.sh_size;
sh_align = s->s_shdr.s_shdr64.sh_addralign;
}
if (sh_type == SHT_NULL)
return (NULL);
if ((elftype = _libelf_xlate_shtype(sh_type)) < ELF_T_FIRST ||
elftype > ELF_T_LAST || (sh_type != SHT_NOBITS &&
sh_offset + sh_size > (uint64_t) e->e_rawsize)) {
LIBELF_SET_ERROR(SECTION, 0);
return (NULL);
}
if ((fsz = (elfclass == ELFCLASS32 ? elf32_fsize : elf64_fsize)
(elftype, (size_t) 1, e->e_version)) == 0) {
LIBELF_SET_ERROR(UNIMPL, 0);
return (NULL);
}
if (sh_size % fsz) {
LIBELF_SET_ERROR(SECTION, 0);
return (NULL);
}
count = sh_size / fsz;
msz = _libelf_msize(elftype, elfclass, e->e_version);
assert(msz > 0);
if ((d = _libelf_allocate_data(s)) == NULL)
return (NULL);
d->d_buf = NULL;
d->d_off = 0;
d->d_align = sh_align;
d->d_size = msz * count;
d->d_type = elftype;
d->d_version = e->e_version;
if (sh_type == SHT_NOBITS || sh_size == 0) {
STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
return (d);
}
if ((d->d_buf = malloc(msz*count)) == NULL) {
(void) _libelf_release_data(d);
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
d->d_flags |= LIBELF_F_MALLOCED;
xlate = _libelf_get_translator(elftype, ELF_TOMEMORY, elfclass);
if (!(*xlate)(d->d_buf, d->d_size, e->e_rawfile + sh_offset, count,
e->e_byteorder != LIBELF_PRIVATE(byteorder))) {
_libelf_release_data(d);
LIBELF_SET_ERROR(DATA, 0);
return (NULL);
}
STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
return (d);
}
Elf_Data *
elf_newdata(Elf_Scn *s)
{
Elf *e;
Elf_Data *d;
if (s == NULL || (e = s->s_elf) == NULL ||
e->e_kind != ELF_K_ELF) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
/*
* elf_newdata() has to append a data descriptor, so
* bring in existing section data if not already present.
*/
if (e->e_rawfile && s->s_size > 0 && STAILQ_EMPTY(&s->s_data))
if (elf_getdata(s, NULL) == NULL)
return (NULL);
if ((d = _libelf_allocate_data(s)) == NULL)
return (NULL);
STAILQ_INSERT_TAIL(&s->s_data, d, d_next);
d->d_align = 1;
d->d_buf = NULL;
d->d_off = (uint64_t) ~0;
d->d_size = 0;
d->d_type = ELF_T_BYTE;
d->d_version = LIBELF_PRIVATE(version);
(void) elf_flagscn(s, ELF_C_SET, ELF_F_DIRTY);
return (d);
}
/*
* Retrieve a data descriptor for raw (untranslated) data for section
* `s'.
*/
Elf_Data *
elf_rawdata(Elf_Scn *s, Elf_Data *d)
{
Elf *e;
int elf_class;
uint32_t sh_type;
uint64_t sh_align, sh_offset, sh_size;
if (s == NULL || (e = s->s_elf) == NULL ||
e->e_kind != ELF_K_ELF || e->e_rawfile == NULL) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
if (d == NULL && (d = STAILQ_FIRST(&s->s_rawdata)) != NULL)
return (d);
if (d != NULL)
return (STAILQ_NEXT(d, d_next));
elf_class = e->e_class;
assert(elf_class == ELFCLASS32 || elf_class == ELFCLASS64);
if (elf_class == ELFCLASS32) {
sh_type = s->s_shdr.s_shdr32.sh_type;
sh_offset = (uint64_t) s->s_shdr.s_shdr32.sh_offset;
sh_size = (uint64_t) s->s_shdr.s_shdr32.sh_size;
sh_align = (uint64_t) s->s_shdr.s_shdr32.sh_addralign;
} else {
sh_type = s->s_shdr.s_shdr64.sh_type;
sh_offset = s->s_shdr.s_shdr64.sh_offset;
sh_size = s->s_shdr.s_shdr64.sh_size;
sh_align = s->s_shdr.s_shdr64.sh_addralign;
}
if (sh_type == SHT_NULL)
return (NULL);
if ((d = _libelf_allocate_data(s)) == NULL)
return (NULL);
d->d_buf = (sh_type == SHT_NOBITS || sh_size == 0) ? NULL :
e->e_rawfile + sh_offset;
d->d_off = 0;
d->d_align = sh_align;
d->d_size = sh_size;
d->d_type = ELF_T_BYTE;
d->d_version = e->e_version;
STAILQ_INSERT_TAIL(&s->s_rawdata, d, d_next);
return (d);
}