304 lines
9 KiB
C
304 lines
9 KiB
C
/*
|
|
* Copyright (c) 2006, Swedish Institute of Computer Science
|
|
* 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.
|
|
* 3. Neither the name of the Institute nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.
|
|
*
|
|
* @(#)$Id: cle.c,v 1.1 2006/12/01 15:12:27 bg- Exp $
|
|
*/
|
|
|
|
/*
|
|
* The Contiki dynamic Link Editor (CLE), ELF version.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
|
|
#include "contiki.h"
|
|
|
|
#include "loader/cle.h"
|
|
#include "loader/elf32.h"
|
|
#include "loader/symtab.h"
|
|
|
|
#define NDEBUG
|
|
#include "lib/assert.h"
|
|
|
|
#ifdef NDEBUG
|
|
#define PRINTF(...) do {} while (0)
|
|
#else
|
|
#define PRINTF(...) printf(__VA_ARGS__)
|
|
#endif
|
|
|
|
/*
|
|
* Parse object file located at offset start reading data using function
|
|
* pread. Save what is useful in info.
|
|
*/
|
|
int
|
|
cle_read_info(struct cle_info *info,
|
|
int (*pread)(void *, int, off_t),
|
|
off_t start)
|
|
{
|
|
/*
|
|
* Save stackspace by using a union!
|
|
*
|
|
* Beware that the contents of ehdr is gone when shdr is written!!!
|
|
*/
|
|
union {
|
|
struct elf32_ehdr ehdr;
|
|
struct elf32_shdr shdr;
|
|
} huge;
|
|
#define ehdr huge.ehdr
|
|
#define shdr huge.shdr
|
|
|
|
off_t shdrptr;
|
|
cle_off strs;
|
|
cle_half shnum; /* number shdrs */
|
|
cle_half shentsize; /* sizeof shdr */
|
|
cle_word strtabsize = 0;
|
|
int i, ret;
|
|
|
|
memset(info, 0x0, sizeof(*info));
|
|
|
|
ret = pread(&ehdr, sizeof(ehdr), start);
|
|
assert(ret > 0);
|
|
|
|
/* Make sure that we have a correct and compatible ELF header. */
|
|
if(memcmp(ehdr.e_ident, ELF_MAGIC_HEADER, ELF_MAGIC_HEADER_SIZE) != 0) {
|
|
return CLE_BAD_HEADER;
|
|
}
|
|
|
|
shdrptr = ehdr.e_shoff;
|
|
shentsize = ehdr.e_shentsize;
|
|
shnum = ehdr.e_shnum;
|
|
|
|
/* The string table section: holds the names of the sections. */
|
|
ret = pread(&shdr, sizeof(shdr), start + shdrptr + shentsize*ehdr.e_shstrndx);
|
|
assert(ret > 0);
|
|
|
|
/* BEWARE THAT ehdr IS NOW OVERWRITTEN!!! */
|
|
|
|
/*
|
|
* Get a pointer to the actual table of strings. This table holds
|
|
* the names of the sections, not the names of other symbols in the
|
|
* file (these are in the symtab section).
|
|
*/
|
|
strs = shdr.sh_offset;
|
|
|
|
/*
|
|
* The ".text" segment holds the actual code from the ELF file, the
|
|
* ".data" segment contains initialized data, the ".bss" segment
|
|
* holds the size of the unitialized data segment. The ".rela.text"
|
|
* and ".rela.data" segments contains relocation information for the
|
|
* contents of the ".text" and ".data" segments, respectively. The
|
|
* ".symtab" segment contains the symbol table for this file. The
|
|
* ".strtab" segment points to the actual string names used by the
|
|
* symbol table.
|
|
*
|
|
* In addition to grabbing pointers to the relevant sections, we
|
|
* also save the section index for resolving addresses in the
|
|
* relocator code.
|
|
*/
|
|
for(i = 0; i < shnum; ++i) {
|
|
ret = pread(&shdr, sizeof(shdr), shdrptr);
|
|
assert(ret > 0);
|
|
|
|
/* The name of the section is contained in the strings table. */
|
|
ret = pread(info->name, sizeof(info->name), start + strs + shdr.sh_name);
|
|
assert(ret > 0);
|
|
|
|
if(strncmp(info->name, ".text", 5) == 0) {
|
|
info->textoff = shdr.sh_offset;
|
|
info->textsize = shdr.sh_size;
|
|
info->text_shndx = i;
|
|
} else if(strncmp(info->name, ".rela.text", 10) == 0) {
|
|
info->textrelaoff = shdr.sh_offset;
|
|
info->textrelasize = shdr.sh_size;
|
|
} else if(strncmp(info->name, ".data", 5) == 0) {
|
|
info->dataoff = shdr.sh_offset;
|
|
info->datasize = shdr.sh_size;
|
|
info->data_shndx = i;
|
|
} else if(strncmp(info->name, ".rela.data", 10) == 0) {
|
|
info->datarelaoff = shdr.sh_offset;
|
|
info->datarelasize = shdr.sh_size;
|
|
} else if(strncmp(info->name, ".symtab", 7) == 0) {
|
|
info->symtaboff = shdr.sh_offset;
|
|
info->symtabsize = shdr.sh_size;
|
|
} else if(strncmp(info->name, ".strtab", 7) == 0) {
|
|
info->strtaboff = shdr.sh_offset;
|
|
strtabsize = shdr.sh_size;
|
|
} else if(strncmp(info->name, ".bss", 4) == 0) {
|
|
info->bsssize = shdr.sh_size;
|
|
info->bss_shndx = i;
|
|
} else {
|
|
info->name[sizeof(info->name) - 1] = 0;
|
|
PRINTF("cle: unknown section %.12s\n", info->name);
|
|
}
|
|
|
|
/* Move on to the next section header. */
|
|
shdrptr += shentsize;
|
|
}
|
|
|
|
if(info->symtabsize == 0) {
|
|
return CLE_NO_SYMTAB;
|
|
}
|
|
if(strtabsize == 0) {
|
|
return CLE_NO_STRTAB;
|
|
}
|
|
if(info->textsize == 0) {
|
|
return CLE_NO_TEXT;
|
|
}
|
|
|
|
return CLE_OK;
|
|
}
|
|
|
|
/*
|
|
* Update one reloc.
|
|
*
|
|
* Writing relocs is machine dependent and this function is MPS430
|
|
* specific!
|
|
*/
|
|
static inline int
|
|
cle_upd_reloc(cle_addr segmem, struct elf32_rela *rela, cle_addr addr)
|
|
{
|
|
memcpy(segmem + rela->r_offset, &addr, 2); /* Write reloc */
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Relocate one segment that has been copied to the location pointed
|
|
* to by segmem.
|
|
*
|
|
* Relocation info is read from offset reloff to (reloff + relsize)
|
|
* and the start of the object file is at start. Data is read using
|
|
* function pread.
|
|
*/
|
|
int
|
|
cle_relocate(struct cle_info *info,
|
|
int (*pread)(void *, int, off_t),
|
|
off_t start, /* Offset to start of file. */
|
|
cle_addr segmem, /* Where segment is stored in memory. */
|
|
cle_off reloff, /* .rela.<segment> start */
|
|
cle_word relsize) /* .rela.<segment> size */
|
|
{
|
|
struct elf32_rela rela;
|
|
struct elf32_sym s;
|
|
off_t off;
|
|
cle_addr addr;
|
|
int ret;
|
|
|
|
for(off = start + reloff;
|
|
off < start + reloff + relsize;
|
|
off += sizeof(struct elf32_rela)) {
|
|
ret = pread(&rela, sizeof(rela), off);
|
|
assert(ret > 0);
|
|
ret = pread(&s, sizeof(s),
|
|
start + info->symtaboff
|
|
+ sizeof(struct elf32_sym)*ELF32_R_SYM(rela.r_info));
|
|
assert(ret > 0);
|
|
|
|
if(s.st_shndx == info->bss_shndx) {
|
|
addr = info->bss;
|
|
} else if(s.st_shndx == info->data_shndx) {
|
|
addr = info->data;
|
|
} else if(s.st_shndx == info->text_shndx) {
|
|
addr = info->text;
|
|
} else {
|
|
addr = NULL;
|
|
}
|
|
|
|
if(s.st_name == 0) { /* No name, local symbol? */
|
|
if(addr == NULL) {
|
|
return CLE_UNKNOWN_SEGMENT;
|
|
}
|
|
} else {
|
|
ret = pread(info->name, sizeof(info->name),
|
|
start + info->strtaboff + s.st_name);
|
|
assert(ret > 0);
|
|
cle_addr sym = symtab_lookup(info->name);
|
|
|
|
if(addr == NULL && sym != NULL) { /* Imported symbol. */
|
|
addr = sym;
|
|
} else if(addr != NULL && sym == NULL) { /* Exported symbol. */
|
|
addr = addr + s.st_value;
|
|
} else if(addr == NULL && sym == NULL) {
|
|
PRINTF("cle: undefined reference to %.32s\n", info->name);
|
|
return CLE_UNDEFINED; /* Or COMMON symbol. */
|
|
} else if(addr != NULL && sym != NULL) {
|
|
PRINTF("cle: multiple definitions of %.32s\n", info->name);
|
|
return CLE_MULTIPLY_DEFINED;
|
|
}
|
|
}
|
|
|
|
addr += rela.r_addend;
|
|
|
|
cle_upd_reloc(segmem, &rela, addr);
|
|
}
|
|
return CLE_OK;
|
|
}
|
|
|
|
/*
|
|
* Search object file located at offset start using function
|
|
* pread. Search for symbol named symbol and return its address after
|
|
* relocation or NULL on failure.
|
|
*/
|
|
void *
|
|
cle_lookup(struct cle_info *info,
|
|
int (*pread)(void *, int, off_t),
|
|
off_t start, /* Offset to start of file. */
|
|
const char *symbol)
|
|
|
|
{
|
|
struct elf32_sym s;
|
|
off_t a;
|
|
cle_addr addr;
|
|
int ret;
|
|
|
|
for(a = start + info->symtaboff;
|
|
a < start + info->symtaboff + info->symtabsize;
|
|
a += sizeof(s)) {
|
|
ret = pread(&s, sizeof(s), a);
|
|
assert(ret > 0);
|
|
|
|
if(s.st_name != 0) {
|
|
ret = pread(info->name, sizeof(info->name),
|
|
start + info->strtaboff + s.st_name);
|
|
assert(ret > 0);
|
|
|
|
if(strcmp(info->name, symbol) == 0) { /* Exported symbol found. */
|
|
if(s.st_shndx == info->bss_shndx) {
|
|
addr = info->bss;
|
|
} else if(s.st_shndx == info->data_shndx) {
|
|
addr = info->data;
|
|
} else if(s.st_shndx == info->text_shndx) {
|
|
addr = info->text;
|
|
} else {
|
|
return NULL; /* Really an error! */
|
|
}
|
|
return addr + s.st_value;
|
|
}
|
|
}
|
|
}
|
|
return NULL;
|
|
}
|