获取小精灵部分的偏移量 [英] Get elf sections offsets

问题描述

我正在尝试获取elf文件各部分的偏移量和数据。
我已经有了使用此代码的部分名称：

I'm trying to get the offset and the data of each sections of an elf file. I already have the sections names with this code:

#include <elf.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>

int filesize(int fd)
{
  return (lseek(fd, 0, SEEK_END));
}

void    print_section(Elf64_Shdr *shdr, char *strTab, int shNum)
{
  int   i;

  for(i = 0; i < shNum; i++)
     printf("%02d: %s\n", i, &strTab[shdr[i].sh_name]);
}

int main(int ac, char **av)
{
  void  *data;
  Elf64_Ehdr    *elf;
  Elf64_Shdr    *shdr;
  int       fd;
  char      *strtab;

  fd = open(av[1], O_RDONLY);
  data = mmap(NULL, filesize(fd), PROT_READ, MAP_SHARED, fd, 0);
  elf = (Elf64_Ehdr *) data;
  shdr = (Elf64_Shdr *) (data + elf->e_shoff);
  strtab = (char *)(data + shdr[elf->e_shstrndx].sh_offset);
  print_section(shdr, strtab, elf->e_shnum);
  close(fd);
  return 0;
}

但是我找不到一种方法来获取每个部分的数据也不是它们的起始偏移量。
感谢您的帮助

But I can't find a way to get either the data of each sections nor their starting offset. Thanks for your help

推荐答案

我认为您可以使用 sh_offset 和 shdr [i] .sh_size ：

void    print_section(Elf64_Shdr *shdr, char *strTab, int shNum, uint8_t *data)
{
  int   i;  

  for(i = 0; i < shNum; i++) {
    size_t k;
     printf("%02d: %s Offset %lx\n", i, &strTab[shdr[i].sh_name], 
        shdr[i].sh_offset);
     for (k = shdr[i].sh_offset; k < shdr[i].sh_offset + shdr[i].sh_size; k++) {
       printf("%x", data[k]);
     }   
     printf("\n");
     for (k = shdr[i].sh_offset; k < shdr[i].sh_offset + shdr[i].sh_size; k++) {
       printf("%c", data[k]);
     }   
     printf("\n");
  }
}

并这样称呼它：

print_section(shdr, strtab, elf->e_shnum, (uint8_t*)data);

获取虚拟地址（偏移量）的一种方法：

One way to get the virtual address (offset):

Elf64_Phdr *ph = (Elf64_Phdr *) ((uint8_t *) data + elf->e_phoff);
printf("Virtual address offset: %lx\n", ph->p_vaddr - elf->e_phoff);

这篇关于获取小精灵部分的偏移量的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！