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|
/* vi: set sw=4 ts=4: */
/*
* A small little readelf implementation for uClibc
*
* Copyright (C) 2001 by Lineo, inc.
* Written by Erik Andersen <andersen@lineo.com>, <andersee@debian.org>
*
* Several functions in this file (specifically, elf_find_section_type(),
* elf_find_phdr_type(), and elf_find_dynamic(), were stolen from elflib.c from
* elfvector (http://www.BitWagon.com/elfvector.html) by John F. Reiser
* <jreiser@BitWagon.com>, and which is copyright 2000 BitWagon Software LLC
* (GPL2).
*
* 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 <elf.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
Elf32_Shdr * elf_find_section_type( int key, Elf32_Ehdr *ehdr)
{
int j;
Elf32_Shdr *shdr = (Elf32_Shdr *)(ehdr->e_shoff + (char *)ehdr);
for (j = ehdr->e_shnum; --j>=0; ++shdr) {
if (shdr->sh_type == key) {
return shdr;
}
}
return NULL;
}
Elf32_Phdr * elf_find_phdr_type( int type, Elf32_Ehdr *ehdr)
{
int j;
Elf32_Phdr *phdr = (Elf32_Phdr *)(ehdr->e_phoff + (char *)ehdr);
for (j = ehdr->e_phnum; --j>=0; ++phdr) {
if (type==phdr->p_type) {
return phdr;
}
}
return NULL;
}
/* Returns value if return_val==1, ptr otherwise */
void * elf_find_dynamic(int const key, Elf32_Dyn *dynp,
Elf32_Ehdr *ehdr, int return_val)
{
Elf32_Phdr *pt_text = elf_find_phdr_type(PT_LOAD, ehdr);
unsigned tx_reloc = pt_text->p_vaddr - pt_text->p_offset;
for (; DT_NULL!=dynp->d_tag; ++dynp) {
if (dynp->d_tag == key) {
if (return_val == 1)
return (void *)dynp->d_un.d_val;
else
return (void *)(dynp->d_un.d_val - tx_reloc + (char *)ehdr );
}
}
return NULL;
}
int check_elf_header(Elf32_Ehdr const *const ehdr)
{
if (! ehdr || strncmp((void *)ehdr, ELFMAG, SELFMAG) != 0 ||
ehdr->e_ident[EI_CLASS] != ELFCLASS32 ||
ehdr->e_ident[EI_VERSION] != EV_CURRENT)
{
return 1;
}
return 0;
}
#define ELFOSABI_NONE 0 /* UNIX System V ABI */
#define ELFOSABI_HPUX 1 /* HP-UX operating system */
#define ELFOSABI_NETBSD 2 /* NetBSD */
#define ELFOSABI_LINUX 3 /* GNU/Linux */
#define ELFOSABI_HURD 4 /* GNU/Hurd */
#define ELFOSABI_SOLARIS 6 /* Solaris */
#define ELFOSABI_AIX 7 /* AIX */
#define ELFOSABI_IRIX 8 /* IRIX */
#define ELFOSABI_FREEBSD 9 /* FreeBSD */
#define ELFOSABI_TRU64 10 /* TRU64 UNIX */
#define ELFOSABI_MODESTO 11 /* Novell Modesto */
#define ELFOSABI_OPENBSD 12 /* OpenBSD */
#define ELFOSABI_STANDALONE 255 /* Standalone (embedded) application */
#define ELFOSABI_ARM 97 /* ARM */
static void describe_elf_hdr(Elf32_Ehdr* ehdr)
{
char *tmp, *tmp1;
switch (ehdr->e_type) {
case ET_NONE: tmp = "None"; tmp1 = "NONE"; break;
case ET_REL: tmp = "Relocatable File"; tmp1 = "REL"; break;
case ET_EXEC: tmp = "Executable file"; tmp1 = "EXEC"; break;
case ET_DYN: tmp = "Shared object file"; tmp1 = "DYN"; break;
case ET_CORE: tmp = "Core file"; tmp1 = "CORE"; break;
default:
tmp = tmp1 = "Unknown";
}
printf( "Type:\t\t%s (%s)\n", tmp1, tmp);
switch (ehdr->e_machine) {
case EM_NONE: tmp="No machine"; break;
case EM_M32: tmp="AT&T WE 32100"; break;
case EM_SPARC: tmp="SUN SPARC"; break;
case EM_386: tmp="Intel 80386"; break;
case EM_68K: tmp="Motorola m68k family"; break;
case EM_88K: tmp="Motorola m88k family"; break;
case EM_860: tmp="Intel 80860"; break;
case EM_MIPS: tmp="MIPS R3000 big-endian"; break;
case EM_S370: tmp="IBM System/370"; break;
case EM_MIPS_RS3_LE: tmp="MIPS R3000 little-endian"; break;
case EM_PARISC: tmp="HPPA"; break;
case EM_VPP500: tmp="Fujitsu VPP500"; break;
case EM_SPARC32PLUS: tmp="Sun's v8plus"; break;
case EM_960: tmp="Intel 80960"; break;
case EM_PPC: tmp="PowerPC"; break;
case EM_PPC64: tmp="PowerPC 64-bit"; break;
case EM_S390: tmp="IBM S390"; break;
case EM_V800: tmp="NEC V800 series"; break;
case EM_FR20: tmp="Fujitsu FR20"; break;
case EM_RH32: tmp="TRW RH-32"; break;
case EM_RCE: tmp="Motorola RCE"; break;
case EM_ARM: tmp="ARM"; break;
case EM_FAKE_ALPHA: tmp="Digital Alpha"; break;
case EM_SH: tmp="Hitachi SH"; break;
case EM_SPARCV9: tmp="SPARC v9 64-bit"; break;
case EM_TRICORE: tmp="Siemens Tricore"; break;
case EM_ARC: tmp="Argonaut RISC Core"; break;
case EM_H8_300: tmp="Hitachi H8/300"; break;
case EM_H8_300H: tmp="Hitachi H8/300H"; break;
case EM_H8S: tmp="Hitachi H8S"; break;
case EM_H8_500: tmp="Hitachi H8/500"; break;
case EM_IA_64: tmp="Intel Merced"; break;
case EM_MIPS_X: tmp="Stanford MIPS-X"; break;
case EM_COLDFIRE: tmp="Motorola Coldfire"; break;
case EM_68HC12: tmp="Motorola M68HC12"; break;
case EM_MMA: tmp="Fujitsu MMA Multimedia Accelerator"; break;
case EM_PCP: tmp="Siemens PCP"; break;
case EM_NCPU: tmp="Sony nCPU embeeded RISC"; break;
case EM_NDR1: tmp="Denso NDR1 microprocessor"; break;
case EM_STARCORE: tmp="Motorola Start*Core processor"; break;
case EM_ME16: tmp="Toyota ME16 processor"; break;
case EM_ST100: tmp="STMicroelectronic ST100 processor"; break;
case EM_TINYJ: tmp="Advanced Logic Corp. Tinyj emb.fam"; break;
case EM_X86_64: tmp="AMD x86-64 architecture"; break;
case EM_PDSP: tmp="Sony DSP Processor"; break;
case EM_FX66: tmp="Siemens FX66 microcontroller"; break;
case EM_ST9PLUS: tmp="STMicroelectronics ST9+ 8/16 mc"; break;
case EM_ST7: tmp="STmicroelectronics ST7 8 bit mc"; break;
case EM_68HC16: tmp="Motorola MC68HC16 microcontroller"; break;
case EM_68HC11: tmp="Motorola MC68HC11 microcontroller"; break;
case EM_68HC08: tmp="Motorola MC68HC08 microcontroller"; break;
case EM_68HC05: tmp="Motorola MC68HC05 microcontroller"; break;
case EM_SVX: tmp="Silicon Graphics SVx"; break;
case EM_AT19: tmp="STMicroelectronics ST19 8 bit mc"; break;
case EM_VAX: tmp="Digital VAX"; break;
case EM_CRIS: tmp="Axis Communications 32-bit embedded processor"; break;
case EM_JAVELIN: tmp="Infineon Technologies 32-bit embedded processor"; break;
case EM_FIREPATH: tmp="Element 14 64-bit DSP Processor"; break;
case EM_ZSP: tmp="LSI Logic 16-bit DSP Processor"; break;
case EM_MMIX: tmp="Donald Knuth's educational 64-bit processor"; break;
case EM_HUANY: tmp="Harvard University machine-independent object files"; break;
case EM_PRISM: tmp="SiTera Prism"; break;
case EM_AVR: tmp="Atmel AVR 8-bit microcontroller"; break;
case EM_FR30: tmp="Fujitsu FR30"; break;
case EM_D10V: tmp="Mitsubishi D10V"; break;
case EM_D30V: tmp="Mitsubishi D30V"; break;
case EM_V850: tmp="NEC v850"; break;
case EM_M32R: tmp="Mitsubishi M32R"; break;
case EM_MN10300: tmp="Matsushita MN10300"; break;
case EM_MN10200: tmp="Matsushita MN10200"; break;
case EM_PJ: tmp="picoJava"; break;
default: tmp="unknown";
}
printf( "Machine:\t%s\n", tmp);
switch (ehdr->e_ident[EI_CLASS]) {
case ELFCLASSNONE: tmp = "Invalid class"; break;
case ELFCLASS32: tmp = "ELF32"; break;
case ELFCLASS64: tmp = "ELF64"; break;
default: tmp = "Unknown";
}
printf( "Class:\t\t%s\n", tmp);
switch (ehdr->e_ident[EI_DATA]) {
case ELFDATANONE: tmp = "Invalid data encoding"; break;
case ELFDATA2LSB: tmp = "2's complement, little endian"; break;
case ELFDATA2MSB: tmp = "2's complement, big endian"; break;
default: tmp = "Unknown";
}
printf( "Data:\t\t%s\n", tmp);
printf( "Version:\t%d %s\n", ehdr->e_ident[EI_VERSION],
(ehdr->e_ident[EI_VERSION]==EV_CURRENT)?
"(current)" : "(unknown: %lx)");
switch (ehdr->e_ident[EI_OSABI]) {
case ELFOSABI_SYSV: tmp ="UNIX - System V"; break;
case ELFOSABI_HPUX: tmp ="UNIX - HP-UX"; break;
case ELFOSABI_NETBSD: tmp ="UNIX - NetBSD"; break;
case ELFOSABI_LINUX: tmp ="UNIX - Linux"; break;
case ELFOSABI_HURD: tmp ="GNU/Hurd"; break;
case ELFOSABI_SOLARIS: tmp ="UNIX - Solaris"; break;
case ELFOSABI_AIX: tmp ="UNIX - AIX"; break;
case ELFOSABI_IRIX: tmp ="UNIX - IRIX"; break;
case ELFOSABI_FREEBSD: tmp ="UNIX - FreeBSD"; break;
case ELFOSABI_TRU64: tmp ="UNIX - TRU64"; break;
case ELFOSABI_MODESTO: tmp ="Novell - Modesto"; break;
case ELFOSABI_OPENBSD: tmp ="UNIX - OpenBSD"; break;
case ELFOSABI_STANDALONE: tmp ="Standalone App"; break;
case ELFOSABI_ARM: tmp ="ARM"; break;
default: tmp = "Unknown";
}
printf( "OS/ABI:\t\t%s\n", tmp);
printf( "ABI Version:\t%d\n", ehdr->e_ident[EI_ABIVERSION]);
}
static void list_needed_libraries(Elf32_Dyn* dynamic, char *strtab)
{
Elf32_Dyn *dyns;
printf("Dependancies:\n");
for (dyns=dynamic; dyns->d_tag!=DT_NULL; ++dyns) {
if (dyns->d_tag == DT_NEEDED) {
printf("\t%s\n", (char*)strtab + dyns->d_un.d_val);
}
}
}
static void describe_elf_interpreter(Elf32_Ehdr* ehdr)
{
Elf32_Phdr *phdr;
phdr = elf_find_phdr_type(PT_INTERP, ehdr);
if (phdr) {
printf("Interpreter:\t%s\n", (char*)ehdr + phdr->p_offset);
}
}
int main( int argc, char** argv)
{
/* map the .so, and locate interesting pieces */
char *dynstr;
char *thefilename = argv[1];
FILE *thefile;
struct stat statbuf;
Elf32_Ehdr *ehdr = 0;
Elf32_Shdr *dynsec;
Elf32_Dyn *dynamic;
if (!thefilename) {
fprintf(stderr, "No filename specified.\n");
exit(EXIT_FAILURE);
}
if (!(thefile = fopen(thefilename, "r"))) {
perror(thefilename);
exit(EXIT_FAILURE);
}
if (fstat(fileno(thefile), &statbuf) < 0) {
perror(thefilename);
exit(EXIT_FAILURE);
}
if (statbuf.st_size < sizeof(Elf32_Ehdr))
goto foo;
/* mmap the file to make reading stuff from it effortless */
ehdr = (Elf32_Ehdr *)mmap(0, statbuf.st_size,
PROT_READ|PROT_WRITE, MAP_PRIVATE, fileno(thefile), 0);
foo:
/* Check if this looks legit */
if (check_elf_header(ehdr)) {
fprintf(stderr, "This does not appear to be an ELF file.\n");
exit(EXIT_FAILURE);
}
describe_elf_hdr(ehdr);
describe_elf_interpreter(ehdr);
dynsec = elf_find_section_type(SHT_DYNAMIC, ehdr);
if (dynsec) {
dynamic = (Elf32_Dyn*)(dynsec->sh_offset + (int)ehdr);
dynstr = (char *)elf_find_dynamic(DT_STRTAB, dynamic, ehdr, 0);
list_needed_libraries(dynamic, dynstr);
}
return 0;
}
|
