mspdebug/elf32.c

343 lines
6.5 KiB
C

/* MSPDebug - debugging tool for the eZ430
* Copyright (C) 2009, 2010 Daniel Beer
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <elf.h>
#include "binfile.h"
#define EM_MSP430 0x69
static const u_int8_t elf32_id[] = {
ELFMAG0, ELFMAG1, ELFMAG2, ELFMAG3, ELFCLASS32
};
#define MAX_PHDRS 32
#define MAX_SHDRS 32
static Elf32_Ehdr file_ehdr;
static Elf32_Phdr file_phdrs[MAX_PHDRS];
static Elf32_Shdr file_shdrs[MAX_SHDRS];
static char *string_tab;
static int string_len;
static int read_ehdr(FILE *in)
{
int i;
/* Read and check the ELF header */
rewind(in);
if (fread(&file_ehdr, sizeof(file_ehdr), 1, in) < 0) {
perror("elf32: couldn't read ELF header");
return -1;
}
for (i = 0; i < sizeof(elf32_id); i++)
if (file_ehdr.e_ident[i] != elf32_id[i]) {
fprintf(stderr, "elf32: not an ELF32 file\n");
return -1;
}
return 0;
}
static int read_phdr(FILE *in)
{
int i;
if (file_ehdr.e_phnum > MAX_PHDRS) {
fprintf(stderr, "elf32: too many program headers: %d\n",
file_ehdr.e_phnum);
return -1;
}
for (i = 0; i < file_ehdr.e_phnum; i++) {
if (fseek(in, i * file_ehdr.e_phentsize + file_ehdr.e_phoff,
SEEK_SET) < 0) {
fprintf(stderr, "elf32: can't seek to phdr %d\n", i);
return -1;
}
if (fread(&file_phdrs[i], sizeof(file_phdrs[0]), 1, in) < 0) {
fprintf(stderr, "elf32: can't read phdr %d: %s\n",
i, strerror(errno));
return -1;
}
}
return 0;
}
static int read_shdr(FILE *in)
{
int i;
if (file_ehdr.e_shnum > MAX_SHDRS) {
fprintf(stderr, "elf32: too many section headers: %d\n",
file_ehdr.e_shnum);
return -1;
}
for (i = 0; i < file_ehdr.e_shnum; i++) {
if (fseek(in, i * file_ehdr.e_shentsize + file_ehdr.e_shoff,
SEEK_SET) < 0) {
fprintf(stderr, "elf32: can't seek to shdr %d\n", i);
return -1;
}
if (fread(&file_shdrs[i], sizeof(file_shdrs[0]), 1, in) < 0) {
fprintf(stderr, "elf32: can't read shdr %d: %s\n",
i, strerror(errno));
return -1;
}
}
return 0;
}
static u_int32_t file_to_phys(u_int32_t v)
{
int i;
for (i = 0; i < file_ehdr.e_phnum; i++) {
Elf32_Phdr *p = &file_phdrs[i];
if (v >= p->p_offset && v - p->p_offset < p->p_filesz)
return v - p->p_offset + p->p_paddr;
}
return v;
}
static int feed_section(FILE *in, int offset, int size, imgfunc_t cb)
{
u_int8_t buf[1024];
u_int16_t addr = file_to_phys(offset);
if (fseek(in, offset, SEEK_SET) < 0) {
perror("elf32: can't seek to section");
return -1;
}
while (size) {
int ask = size > sizeof(buf) ? sizeof(buf) : size;
int len = fread(buf, 1, ask, in);
if (len < 0) {
perror("elf32: can't read section");
return -1;
}
if (cb(addr, buf, len) < 0)
return -1;
size -= len;
offset += len;
addr += len;
}
return 0;
}
static int read_all(FILE *in)
{
if (read_ehdr(in) < 0)
return -1;
if (file_ehdr.e_machine != EM_MSP430) {
fprintf(stderr, "elf32: this is not an MSP430 ELF32\n");
return -1;
}
if (read_phdr(in) < 0)
return -1;
if (read_shdr(in) < 0)
return -1;
return 0;
}
int elf32_extract(FILE *in, imgfunc_t cb)
{
int i;
if (read_all(in) < 0)
return -1;
for (i = 0; i < file_ehdr.e_shnum; i++) {
Elf32_Shdr *s = &file_shdrs[i];
if (s->sh_type == SHT_PROGBITS && s->sh_flags & SHF_ALLOC &&
feed_section(in, s->sh_offset, s->sh_size, cb) < 0)
return -1;
}
return 0;
}
int elf32_check(FILE *in)
{
int i;
rewind(in);
for (i = 0; i < sizeof(elf32_id); i++)
if (fgetc(in) != elf32_id[i])
return 0;
return 1;
}
static Elf32_Shdr *find_shdr(Elf32_Word type)
{
int i;
for (i = 0; i < file_ehdr.e_shnum; i++) {
Elf32_Shdr *s = &file_shdrs[i];
if (s->sh_type == type)
return s;
}
return NULL;
}
static int syms_load_strings(FILE *in, Elf32_Shdr *s)
{
int len = s->sh_size;
int offset = 0;
if (!len)
return 0;
if (fseek(in, s->sh_offset, SEEK_SET) < 0) {
perror("elf32: can't seek to strings");
return -1;
}
string_len = len;
string_tab = malloc(len + 1);
if (!string_tab) {
perror("elf32: can't allocate string table memory");
return -1;
}
while (len) {
char buf[1024];
int req = sizeof(buf) > len ? len : sizeof(buf);
int count = fread(buf, 1, req, in);
if (!count) {
fprintf(stderr, "elf32: eof reading strings\n");
return -1;
}
if (count < 0) {
perror("elf32: error reading strings");
return -1;
}
memcpy(string_tab + offset, buf, count);
offset += count;
len -= count;
}
string_tab[string_len] = 0;
return 0;
}
#define N_SYMS 128
static int syms_load_syms(FILE *in, Elf32_Shdr *s, symfunc_t cb)
{
Elf32_Sym syms[N_SYMS];
int len = s->sh_size / sizeof(syms[0]);
if (fseek(in, s->sh_offset, SEEK_SET) < 0) {
perror("elf32: can't seek to symbols");
return -1;
}
while (len) {
int req = N_SYMS > len ? len : N_SYMS;
int count = fread(syms, sizeof(syms[0]), req, in);
int i;
if (!count) {
fprintf(stderr, "elf32: eof reading symbols\n");
return -1;
}
if (count < 0) {
perror("elf32: error reading symbols");
return -1;
}
for (i = 0; i < count; i++) {
Elf32_Sym *y = &syms[i];
if (y->st_name > string_len) {
fprintf(stderr, "elf32: symbol out of "
"bounds\n");
return -1;
}
if (cb(string_tab + y->st_name, y->st_value) < 0)
return -1;
}
len -= count;
}
return 0;
}
int elf32_syms(FILE *in, symfunc_t cb)
{
Elf32_Shdr *s;
if (read_all(in) < 0)
return -1;
s = find_shdr(SHT_SYMTAB);
if (!s) {
fprintf(stderr, "elf32: no symbol table\n");
return -1;
}
if (s->sh_link <= 0 || s->sh_link >= file_ehdr.e_shnum) {
fprintf(stderr, "elf32: no string table\n");
return -1;
}
string_tab = NULL;
string_len = 0;
if (syms_load_strings(in, &file_shdrs[s->sh_link]) < 0 ||
syms_load_syms(in, s, cb) < 0) {
if (string_tab)
free(string_tab);
return -1;
}
if (string_tab)
free(string_tab);
return 0;
}