/*-
* 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.
*
* $FreeBSD: src/lib/libelf/libelf_ehdr.c,v 1.2 2006/12/25 02:22:22 jkoshy Exp $
*/
#include <assert.h>
#include "gelf.h"
#include "libelf.h"
#include <stdlib.h>
#include "_libelf.h"
/*
* Retrieve counts for sections, phdrs and the section string table index
* from section header #0 of the ELF object.
*/
static int
_libelf_load_extended(Elf *e, int ec, uint64_t shoff, uint16_t phnum,
uint16_t strndx)
{
Elf_Scn *scn;
size_t fsz;
void (*xlator)(char *_d, char *_s, size_t _c, int _swap);
uint32_t shtype;
assert(STAILQ_EMPTY(&e->e_u.e_elf.e_scn));
fsz = _libelf_fsize(ELF_T_SHDR, ec, e->e_version, 1);
assert(fsz > 0);
if (e->e_rawsize < shoff + fsz) { /* raw file too small */
LIBELF_SET_ERROR(HEADER, 0);
return (0);
}
if ((scn = _libelf_allocate_scn(e, (size_t) 0)) == NULL)
return (0);
xlator = _libelf_get_translator(ELF_T_SHDR, ELF_TOMEMORY, ec);
(*xlator)((char *) &scn->s_shdr, e->e_rawfile + shoff, (size_t) 1,
e->e_byteorder != LIBELF_PRIVATE(byteorder));
#define GET_SHDR_MEMBER(M) ((ec == ELFCLASS32) ? scn->s_shdr.s_shdr32.M : \
scn->s_shdr.s_shdr64.M)
if ((shtype = GET_SHDR_MEMBER(sh_type)) != SHT_NULL) {
LIBELF_SET_ERROR(SECTION, 0);
return (0);
}
e->e_u.e_elf.e_nscn = GET_SHDR_MEMBER(sh_size);
e->e_u.e_elf.e_nphdr = (phnum != PN_XNUM) ? phnum :
GET_SHDR_MEMBER(sh_info);
e->e_u.e_elf.e_strndx = (strndx != SHN_XINDEX) ? strndx :
GET_SHDR_MEMBER(sh_link);
#undef GET_SHDR_MEMBER
return (1);
}
#define EHDR_INIT(E,SZ) do { \
Elf##SZ##_Ehdr *eh = (E); \
eh->e_ident[EI_MAG0] = ELFMAG0; \
eh->e_ident[EI_MAG1] = ELFMAG1; \
eh->e_ident[EI_MAG2] = ELFMAG2; \
eh->e_ident[EI_MAG3] = ELFMAG3; \
eh->e_ident[EI_CLASS] = ELFCLASS##SZ; \
eh->e_ident[EI_DATA] = ELFDATANONE; \
eh->e_ident[EI_VERSION] = LIBELF_PRIVATE(version); \
eh->e_machine = EM_NONE; \
eh->e_type = ELF_K_NONE; \
eh->e_version = LIBELF_PRIVATE(version); \
} while (0)
void *
_libelf_ehdr(Elf *e, int ec, int allocate)
{
void *ehdr;
size_t fsz, msz;
uint16_t phnum, shnum, strndx;
uint64_t shoff;
void (*xlator)(char *_d, char *_s, size_t _c, int _swap);
assert(ec == ELFCLASS32 || ec == ELFCLASS64);
if (e == NULL || e->e_kind != ELF_K_ELF) {
LIBELF_SET_ERROR(ARGUMENT, 0);
return (NULL);
}
if (e->e_class != ELFCLASSNONE && e->e_class != ec) {
LIBELF_SET_ERROR(CLASS, 0);
return (NULL);
}
if (e->e_version != EV_CURRENT) {
LIBELF_SET_ERROR(VERSION, 0);
return (NULL);
}
if (e->e_class == ELFCLASSNONE)
e->e_class = ec;
if (ec == ELFCLASS32)
ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr32;
else
ehdr = (void *) e->e_u.e_elf.e_ehdr.e_ehdr64;
if (ehdr != NULL) /* already have a translated ehdr */
return (ehdr);
fsz = _libelf_fsize(ELF_T_EHDR, ec, e->e_version, (size_t) 1);
assert(fsz > 0);
if (e->e_cmd != ELF_C_WRITE && e->e_rawsize < fsz) {
LIBELF_SET_ERROR(HEADER, 0);
return (NULL);
}
msz = _libelf_msize(ELF_T_EHDR, ec, EV_CURRENT);
assert(msz > 0);
if ((ehdr = calloc((size_t) 1, msz)) == NULL) {
LIBELF_SET_ERROR(RESOURCE, 0);
return (NULL);
}
if (ec == ELFCLASS32) {
e->e_u.e_elf.e_ehdr.e_ehdr32 = ehdr;
EHDR_INIT(ehdr,32);
} else {
e->e_u.e_elf.e_ehdr.e_ehdr64 = ehdr;
EHDR_INIT(ehdr,64);
}
if (allocate)
e->e_flags |= ELF_F_DIRTY;
if (e->e_cmd == ELF_C_WRITE)
return (ehdr);
xlator = _libelf_get_translator(ELF_T_EHDR, ELF_TOMEMORY, ec);
(*xlator)(ehdr, e->e_rawfile, (size_t) 1,
e->e_byteorder != LIBELF_PRIVATE(byteorder));
/*
* If extended numbering is being used, read the correct
* number of sections and program header entries.
*/
if (ec == ELFCLASS32) {
phnum = ((Elf32_Ehdr *) ehdr)->e_phnum;
shnum = ((Elf32_Ehdr *) ehdr)->e_shnum;
shoff = ((Elf32_Ehdr *) ehdr)->e_shoff;
strndx = ((Elf32_Ehdr *) ehdr)->e_shstrndx;
} else {
phnum = ((Elf64_Ehdr *) ehdr)->e_phnum;
shnum = ((Elf64_Ehdr *) ehdr)->e_shnum;
shoff = ((Elf64_Ehdr *) ehdr)->e_shoff;
strndx = ((Elf64_Ehdr *) ehdr)->e_shstrndx;
}
if (shnum >= SHN_LORESERVE ||
(shoff == 0LL && (shnum != 0 || phnum == PN_XNUM ||
strndx == SHN_XINDEX))) {
LIBELF_SET_ERROR(HEADER, 0);
return (NULL);
}
if (shnum != 0 || shoff == 0LL) { /* not using extended numbering */
e->e_u.e_elf.e_nphdr = phnum;
e->e_u.e_elf.e_nscn = shnum;
e->e_u.e_elf.e_strndx = strndx;
} else if (_libelf_load_extended(e, ec, shoff, phnum, strndx) == 0)
return (NULL);
return (ehdr);
}