读取 ELF 文件的段表字符串表

readELF.c

#include <stdio.h>
#include <elf.h>
#include <string.h>
#include <stdlib.h>

int main(int argc, char **argv)
{
    FILE *fp = fopen("test", "rb");
    if (fp == NULL)
    {
        perror("Error:");
        exit(1);
    }
    Elf64_Shdr *str_section_table = (Elf64_Shdr *)malloc(sizeof(Elf64_Shdr));
    // ELF Header
    Elf64_Ehdr *header = (Elf64_Ehdr *)malloc(sizeof(Elf64_Ehdr));
    // Read ELF header
    fread(header, sizeof(Elf64_Ehdr), 1, fp);
    // Print ELF Magic to verify
    printf("ELF Header:");
    for (int i = 0; i < EI_NIDENT; i++)
    {
        unsigned char byte = header->e_ident[i];
        printf("%c", byte == '\0' ? '.' : byte);
    }
    printf("\n");
    // Get section header table
    printf("Section Table starts at : %d(%x)\n", header->e_shoff, header->e_shoff);
    // Get section number
    printf("There are %d sections.\n", header->e_shnum);
    // get and print each section info.
    fseek(fp, header->e_shoff, 0);
    Elf64_Shdr *section = (Elf64_Shdr *)malloc(sizeof(Elf64_Shdr));
    for (int i = 0; i < header->e_shnum; i++)
    {
        memset(section, '\0', sizeof(Elf64_Shdr));
        fread(section, header->e_shentsize, 1, fp);
        printf("Section [%d] : starts at %d(%x) size %d.\n",
               i, section->sh_offset,
               section->sh_offset,
               section->sh_size);
        if (i == header->e_shstrndx)
        {
            printf("This section No.%d is .shstrtab!\n", i);
            // Now copy .shstrtab
            memset(str_section_table, '\0', sizeof(Elf64_Shdr));
            memcpy(str_section_table, section, sizeof(Elf64_Shdr));
        }
    }
    free(section);
    // Now process string section table
    printf(".shstrtab starts at %d(%x), size %d.\n ",
           str_section_table->sh_offset,
           str_section_table->sh_offset,
           str_section_table->sh_size);
    // read this section
    unsigned char *shstrtab_buff = (unsigned char *)malloc(str_section_table->sh_size);
    fseek(fp, str_section_table->sh_offset, 0);
    fread(shstrtab_buff, str_section_table->sh_size, 1, fp);
    printf("Table content:\n");
    for (int i = 0; i != str_section_table->sh_size; i++)
    {
        unsigned char byte = shstrtab_buff[i];
        printf("%c", byte == '\0'
                         ? '\n'
                         : byte);
    }
}