326 lines
6.9 KiB
C

/*
* Copyright © 2013 Keith Packard <keithp@keithp.com>
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include <err.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include "ao-elf.h"
#include "ao-hex.h"
#include "ao-verbose.h"
/*
* Look through the Elf file for symbols that can be adjusted before
* the image is written to the device
*/
static struct ao_sym *
load_symbols (Elf *e, int *num_symbolsp)
{
Elf_Scn *scn;
Elf_Data *symbol_data = NULL;
GElf_Shdr shdr;
GElf_Sym sym;
int i, symbol_count;
char *symbol_name;
size_t shstrndx;
struct ao_sym *symbols = NULL;
struct ao_sym *symbol;
int num_symbols = 0;
int size_symbols = 0;
if (elf_getshdrstrndx(e, &shstrndx) < 0)
return false;
/*
* Find the symbols
*/
scn = NULL;
while ((scn = elf_nextscn(e, scn)) != NULL) {
if (gelf_getshdr(scn, &shdr) != &shdr)
return false;
if (shdr.sh_type == SHT_SYMTAB) {
symbol_data = elf_getdata(scn, NULL);
symbol_count = shdr.sh_size / shdr.sh_entsize;
break;
}
}
if (!symbol_data)
return NULL;
for (i = 0; i < symbol_count; i++) {
gelf_getsym(symbol_data, i, &sym);
symbol_name = elf_strptr(e, shdr.sh_link, sym.st_name);
if (!symbol_name[0])
continue;
if (num_symbols == size_symbols) {
struct ao_sym *new_symbols;
int new_size;
if (!size_symbols)
new_size = 16;
else
new_size = size_symbols * 2;
new_symbols = realloc(symbols, new_size * sizeof (struct ao_sym));
if (!new_symbols)
goto bail;
symbols = new_symbols;
size_symbols = new_size;
}
symbol = &symbols[num_symbols];
memset(symbol, 0, sizeof (struct ao_sym));
symbol->name = strdup(symbol_name);
if (!symbol->name)
goto bail;
symbol->addr = sym.st_value;
ao_printf(AO_VERBOSE_EXE, "Add symbol %s: %08x\n", symbol->name, symbol->addr);
num_symbols++;
}
*num_symbolsp = num_symbols;
return symbols;
bail:
for (i = 0; i < num_symbols; i++)
free(symbols[i].name);
free(symbols);
return NULL;
}
static uint32_t
round4(uint32_t a) {
return (a + 3) & ~3;
}
static struct ao_hex_image *
new_load (uint32_t addr, uint32_t len)
{
struct ao_hex_image *new;
len = round4(len);
new = calloc (1, sizeof (struct ao_hex_image) + len);
if (!new)
abort();
new->address = addr;
new->length = len;
return new;
}
static void
load_paste(struct ao_hex_image *into, struct ao_hex_image *from)
{
if (from->address < into->address || into->address + into->length < from->address + from->length)
abort();
memcpy(into->data + from->address - into->address, from->data, from->length);
}
/*
* Make a new load structure large enough to hold the old one and
* the new data
*/
static struct ao_hex_image *
expand_load(struct ao_hex_image *from, uint32_t address, uint32_t length)
{
struct ao_hex_image *new;
if (from) {
uint32_t from_last = from->address + from->length;
uint32_t last = address + length;
if (address > from->address)
address = from->address;
if (last < from_last)
last = from_last;
length = last - address;
if (address == from->address && length == from->length)
return from;
}
new = new_load(address, length);
if (from) {
load_paste(new, from);
free (from);
}
return new;
}
/*
* Create a new load structure with data from the existing one
* and the new data
*/
static struct ao_hex_image *
load_write(struct ao_hex_image *from, uint32_t address, uint32_t length, void *data)
{
struct ao_hex_image *new;
new = expand_load(from, address, length);
memcpy(new->data + address - new->address, data, length);
return new;
}
#define DBG 0
/*
* Construct a large in-memory block for all
* of the loaded sections of the program
*/
static struct ao_hex_image *
get_load(Elf *e)
{
Elf_Scn *scn;
size_t shstrndx;
GElf_Shdr shdr;
Elf_Data *data;
size_t nphdr;
size_t p;
GElf_Phdr phdr;
GElf_Addr sh_paddr;
struct ao_hex_image *load = NULL;
#if DBG
char *section_name;
#endif
size_t nshdr;
size_t s;
if (elf_getshdrstrndx(e, &shstrndx) < 0)
return 0;
if (elf_getphdrnum(e, &nphdr) < 0)
return 0;
if (elf_getshdrnum(e, &nshdr) < 0)
return 0;
/*
* As far as I can tell, all of the phdr sections should
* be flashed to memory
*/
for (p = 0; p < nphdr; p++) {
/* Find this phdr */
gelf_getphdr(e, p, &phdr);
if (phdr.p_type != PT_LOAD)
continue;
/* Get the associated file section */
#if DBG
fprintf (stderr, "offset %08x vaddr %08x paddr %08x filesz %08x memsz %08x\n",
(uint32_t) phdr.p_offset,
(uint32_t) phdr.p_vaddr,
(uint32_t) phdr.p_paddr,
(uint32_t) phdr.p_filesz,
(uint32_t) phdr.p_memsz);
#endif
for (s = 0; s < nshdr; s++) {
scn = elf_getscn(e, s);
if (!scn) {
fprintf (stderr, "getscn failed\n");
abort();
}
if (gelf_getshdr(scn, &shdr) != &shdr) {
fprintf (stderr, "gelf_getshdr failed\n");
abort();
}
#if DBG
section_name = elf_strptr(e, shstrndx, shdr.sh_name);
#endif
if (shdr.sh_size != 0 && shdr.sh_type != SHT_NOBITS && (shdr.sh_flags & SHF_ALLOC) &&
phdr.p_offset <= shdr.sh_offset && shdr.sh_offset < phdr.p_offset + phdr.p_filesz)
{
sh_paddr = phdr.p_paddr + shdr.sh_offset - phdr.p_offset;
#if DBG
fprintf (stderr, "\tsize %08x rom %08x exec %08x %s\n",
(uint32_t) shdr.sh_size,
(uint32_t) sh_paddr,
(uint32_t) shdr.sh_addr,
section_name);
#endif
data = elf_getdata(scn, NULL);
/* Write the section data into the memory block */
load = load_write(load, sh_paddr, shdr.sh_size, data->d_buf);
}
}
}
return load;
}
/*
* Open the specified ELF file and
* check for the symbols we need
*/
struct ao_hex_image *
ao_load_elf(char *name, struct ao_sym **symbols, int *num_symbols)
{
int fd;
Elf *e;
size_t shstrndx;
struct ao_hex_image *image;
if (elf_version(EV_CURRENT) == EV_NONE)
return NULL;
fd = open(name, O_RDONLY, 0);
if (fd < 0)
return NULL;
e = elf_begin(fd, ELF_C_READ, NULL);
if (!e)
return NULL;
if (elf_kind(e) != ELF_K_ELF)
return NULL;
if (elf_getshdrstrndx(e, &shstrndx) != 0)
return NULL;
if (symbols)
*symbols = load_symbols(e, num_symbols);
image = get_load(e);
if (!image) {
fprintf (stderr, "Cannot create memory image from file\n");
return NULL;
}
return image;
}