Coding an ELF Parser
To help summarize some of what we have learned, I have included some simple code that will print the program headers and section names of a 32-bit ELF executable. Many more examples of ELF-related code (and much more interesting ones) will be shown throughout this book:
/* elfparse.c – gcc elfparse.c -o elfparse */
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <elf.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <stdint.h>
#include <sys/stat.h>
#include <fcntl.h>
int main(int argc, char **argv)
{
int fd, i;
uint8_t *mem;
struct stat st;
char *StringTable, *interp;
Elf32_Ehdr *ehdr;
Elf32_Phdr *phdr;
Elf32_Shdr *shdr;
if (argc < 2) {
printf("Usage: %s <executable>\n", argv[0]);
exit(0);
}
if ((fd = open(argv[1], O_RDONLY)) < 0) {
perror("open");
exit(-1);
}
if (fstat(fd, &st) <...