add readelf app
This commit is contained in:
K. Lange
parent
29cb305b8c
commit
6bba5dd59e
253
apps/readelf.c
Normal file
253
apps/readelf.c
Normal file
@ -0,0 +1,253 @@
|
||||
/* This file is part of ToaruOS and is released under the terms
|
||||
* of the NCSA / University of Illinois License - see LICENSE.md
|
||||
* Copyright (C) 2013-2014 Kevin Lange
|
||||
*/
|
||||
/*
|
||||
* ToAruOS Miniature ELF Reader
|
||||
* (C) 2011 Kevin Lange
|
||||
*/
|
||||
|
||||
#include <stdio.h>
|
||||
#include <stdlib.h>
|
||||
#include <stdint.h>
|
||||
#include <string.h>
|
||||
#include <kernel/elf.h>
|
||||
|
||||
/**
|
||||
* Show usage for the readelf application.
|
||||
* @param argc Argument count (unused)
|
||||
* @param argv Arguments to binary
|
||||
*/
|
||||
void usage(int argc, char ** argv) {
|
||||
/* Show usage */
|
||||
printf("%s [filename]\n", argv[0]);
|
||||
printf("\tDisplays information on ELF binaries such as section names,\n");
|
||||
printf("\tlocations, sizes, and loading positions in memory.\n");
|
||||
exit(1);
|
||||
}
|
||||
|
||||
/**
|
||||
* Application entry point.
|
||||
* @returns 0 on sucess, 1 on failure
|
||||
*/
|
||||
int main(int argc, char ** argv) {
|
||||
/* Process arguments */
|
||||
if (argc < 2) usage(argc,argv);
|
||||
|
||||
FILE * binary; /**< File pointer for requested executable */
|
||||
size_t binary_size; /**< Size of the file */
|
||||
char * binary_buf; /**< Buffer to store the binary in memory */
|
||||
Elf32_Header * header; /**< ELF header */
|
||||
char * string_table = NULL; /**< The section header string table */
|
||||
char * sym_string_table = NULL; /**< The symbol string table */
|
||||
|
||||
/* Open the requested binary */
|
||||
binary = fopen(argv[1], "r");
|
||||
|
||||
/* Jump to the end so we can get the size */
|
||||
fseek(binary, 0, SEEK_END);
|
||||
binary_size = ftell(binary);
|
||||
fseek(binary, 0, SEEK_SET);
|
||||
|
||||
/* Some sanity checks */
|
||||
if (binary_size < 4 || binary_size > 0xFFFFFFF) {
|
||||
printf("Oh no! I don't quite like the size of this binary.\n");
|
||||
return 1;
|
||||
}
|
||||
printf("Binary is %u bytes.\n", (unsigned int)binary_size);
|
||||
|
||||
/* Read the binary into a buffer */
|
||||
binary_buf = malloc(binary_size);
|
||||
fread((void *)binary_buf, binary_size, 1, binary);
|
||||
|
||||
/* Let's start considering this guy an elf, 'eh? */
|
||||
header = (Elf32_Header *)binary_buf;
|
||||
|
||||
/* Verify the magic */
|
||||
if ( header->e_ident[0] != ELFMAG0 ||
|
||||
header->e_ident[1] != ELFMAG1 ||
|
||||
header->e_ident[2] != ELFMAG2 ||
|
||||
header->e_ident[3] != ELFMAG3) {
|
||||
printf("Header magic is wrong!\n");
|
||||
printf("Are you sure this is a 32-bit ELF binary or object file?\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Let's print out some of the header information, shall we? */
|
||||
printf("\033[1mELF Header\033[0m\n");
|
||||
|
||||
/* File type */
|
||||
printf("[Type %d] ", header->e_type);
|
||||
switch (header->e_type) {
|
||||
case ET_NONE:
|
||||
printf("No file type.\n");
|
||||
break;
|
||||
case ET_REL:
|
||||
printf("Relocatable file.\n");
|
||||
break;
|
||||
case ET_EXEC:
|
||||
printf("Executable file.\n");
|
||||
break;
|
||||
case ET_DYN:
|
||||
printf("Shared object file.\n");
|
||||
break;
|
||||
case ET_CORE:
|
||||
printf("Core file.\n");
|
||||
break;
|
||||
default:
|
||||
printf("(Unknown file type)\n");
|
||||
break;
|
||||
}
|
||||
|
||||
/* Machine Type */
|
||||
switch (header->e_machine) {
|
||||
case EM_386:
|
||||
printf("Intel x86\n");
|
||||
break;
|
||||
default:
|
||||
printf("Unknown machine: %d\n", header->e_machine);
|
||||
break;
|
||||
}
|
||||
|
||||
/* Version == EV_CURRENT? */
|
||||
if (header->e_version == EV_CURRENT) {
|
||||
printf("ELF version is 1, as it should be.\n");
|
||||
}
|
||||
|
||||
/* Entry point in memory */
|
||||
printf("Binary entry point in virtual memory is at 0x%x\n", (unsigned int)header->e_entry);
|
||||
|
||||
/* Program header table offset */
|
||||
printf("Program header table is at +0x%x and one entry is 0x%x bytes.\n"
|
||||
"There are %d total program headers.\n",
|
||||
(unsigned int)header->e_phoff, (unsigned int)header->e_phentsize, (unsigned int)header->e_phnum);
|
||||
|
||||
/* Section header table offset */
|
||||
printf("Section header table is at +0x%x and one entry is 0x%x bytes.\n"
|
||||
"There are %d total section headers.\n",
|
||||
(unsigned int)header->e_shoff, (unsigned int)header->e_shentsize, (unsigned int)header->e_shnum);
|
||||
|
||||
/* Read the program headers */
|
||||
printf("\033[1mProgram Headers\033[0m\n");
|
||||
for (uint32_t x = 0; x < header->e_phentsize * header->e_phnum; x += header->e_phentsize) {
|
||||
if (header->e_phoff + x > binary_size) {
|
||||
printf("Tried to read beyond the end of the file.\n");
|
||||
return 1;
|
||||
}
|
||||
/* Grab the program header */
|
||||
Elf32_Phdr * phdr = (Elf32_Phdr *)((uintptr_t)binary_buf + (header->e_phoff + x));
|
||||
|
||||
/* Print the header type */
|
||||
switch (phdr->p_type) {
|
||||
case PT_LOAD:
|
||||
printf("[Loadable Segment]\n");
|
||||
break;
|
||||
case PT_DYNAMIC:
|
||||
printf("[Dynamic Loading Information]\n");
|
||||
break;
|
||||
case PT_INTERP:
|
||||
printf("[Interpreter Path]\n");
|
||||
break;
|
||||
default:
|
||||
printf("[Unused Segement]\n");
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
uint32_t i = 0;
|
||||
for (uint32_t x = 0; x < header->e_shentsize * header->e_shnum; x += header->e_shentsize) {
|
||||
if (header->e_shoff + x > binary_size) {
|
||||
printf("Tried to read beyond the end of the file.\n");
|
||||
return 1;
|
||||
}
|
||||
Elf32_Shdr * shdr = (Elf32_Shdr *)((uintptr_t)binary_buf + (header->e_shoff + x));
|
||||
if (shdr->sh_type == SHT_STRTAB) {
|
||||
if (i == header->e_shstrndx) {
|
||||
string_table = (char *)((uintptr_t)binary_buf + shdr->sh_offset);
|
||||
printf("Found the section string table at 0x%x\n", (unsigned int)shdr->sh_offset);
|
||||
}
|
||||
}
|
||||
i++;
|
||||
}
|
||||
|
||||
if (!string_table) {
|
||||
printf("No string table, skipping rest of output.\n");
|
||||
return 1;
|
||||
}
|
||||
|
||||
/* Find the (hopefully two) string tables */
|
||||
printf("\033[1mString Tables\033[0m\n");
|
||||
for (uint32_t x = 0; x < header->e_shentsize * header->e_shnum; x += header->e_shentsize) {
|
||||
if (header->e_shoff + x > binary_size) {
|
||||
printf("Tried to read beyond the end of the file.\n");
|
||||
return 1;
|
||||
}
|
||||
Elf32_Shdr * shdr = (Elf32_Shdr *)((uintptr_t)binary_buf + (header->e_shoff + x));
|
||||
if (shdr->sh_type == SHT_STRTAB) {
|
||||
if (!strcmp((char *)((uintptr_t)string_table + shdr->sh_name), ".strtab")) {
|
||||
sym_string_table = (char *)((uintptr_t)binary_buf + shdr->sh_offset);
|
||||
printf("Found the symbol string table at 0x%x\n", (unsigned int)shdr->sh_offset);
|
||||
}
|
||||
printf("Displaying string table at 0x%x\n", (unsigned int)shdr->sh_offset);
|
||||
char * _string_table = (char *)((uintptr_t)binary_buf + shdr->sh_offset);
|
||||
unsigned int j = 1;
|
||||
int k = 0;
|
||||
printf("%d\n", (unsigned int)shdr->sh_size);
|
||||
while (j < shdr->sh_size) {
|
||||
int t = strlen((char *)((uintptr_t)_string_table + j));
|
||||
if (t) {
|
||||
printf("%d [%d] %s\n", k, j, (char *)((uintptr_t)_string_table + j));
|
||||
k++;
|
||||
j += t;
|
||||
} else {
|
||||
j += 1;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/* Read the section headers */
|
||||
printf("\033[1mSection Headers\033[0m\n");
|
||||
for (uint32_t x = 0; x < header->e_shentsize * header->e_shnum; x += header->e_shentsize) {
|
||||
if (header->e_shoff + x > binary_size) {
|
||||
printf("Tried to read beyond the end of the file.\n");
|
||||
return 1;
|
||||
}
|
||||
Elf32_Shdr * shdr = (Elf32_Shdr *)((uintptr_t)binary_buf + (header->e_shoff + x));
|
||||
|
||||
printf("[%d] %s\n", (unsigned int)shdr->sh_type, (char *)((uintptr_t)string_table + shdr->sh_name));
|
||||
printf("Section starts at 0x%x and is 0x%x bytes long.\n", (unsigned int)shdr->sh_offset, (unsigned int)shdr->sh_size);
|
||||
if (shdr->sh_addr) {
|
||||
printf("It should be loaded at 0x%x.\n", (unsigned int)shdr->sh_addr);
|
||||
}
|
||||
}
|
||||
|
||||
#if 1
|
||||
printf("\033[1mSymbol Tables\033[0m\n");
|
||||
for (uint32_t x = 0; x < header->e_shentsize * header->e_shnum; x += header->e_shentsize) {
|
||||
if (header->e_shoff + x > binary_size) {
|
||||
printf("Tried to read beyond the end of the file.\n");
|
||||
return 1;
|
||||
}
|
||||
Elf32_Shdr * shdr = (Elf32_Shdr *)((uintptr_t)binary_buf + (header->e_shoff + x));
|
||||
|
||||
if (shdr->sh_type == SHT_SYMTAB) {
|
||||
printf("Found symbol table: %s\n", (char *)((uintptr_t)string_table + shdr->sh_name));
|
||||
|
||||
Elf32_Sym * table = (Elf32_Sym *)((uintptr_t)binary_buf + (shdr->sh_offset));
|
||||
while ((uintptr_t)table - ((uintptr_t)binary_buf + shdr->sh_offset) < shdr->sh_size) {
|
||||
printf("%s: 0x%x [0x%x]\n", (char *)((uintptr_t)sym_string_table + table->st_name), (unsigned int)table->st_value, (unsigned int)table->st_size);
|
||||
table++;
|
||||
}
|
||||
}
|
||||
}
|
||||
#endif
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* vim:noexpandtab
|
||||
* vim:tabstop=4
|
||||
* vim:shiftwidth=4
|
||||
*/
|
||||
Loading…
Reference in New Issue
Block a user