Les fichiers ELF, la suite

/*
    Ce programme utilise la structure d?clar?e dans /usr/include/linux.h
    
    typedef struct elf64_hdr {
    unsigned char   e_ident[EI_NIDENT]; // ELF "magic number" 
        Elf64_Half e_type;
        Elf64_Half e_machine;
        Elf64_Word e_version;
        Elf64_Addr e_entry;     // Entry point virtual address    
        Elf64_Off e_phoff;      // Program header table file offset 
        Elf64_Off e_shoff;      // Section header table file offset 
        Elf64_Word e_flags;
        Elf64_Half e_shstrndx;
        Elf64_Half e_ehsize;
        Elf64_Half e_phentsize;
        Elf64_Half e_phnum;
        Elf64_Half e_shentsize;
        Elf64_Half e_shnum;
    } Elf64_Ehdr;
    
    Commande de compilation:
    $ gcc simple02.c -o simple02 -no-pie
*/


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


int main(void)
{
    Elf64_Ehdr Ehdr;
    FILE *infile;
    int i;

    infile = fopen("simple01", "r");

    fread(&Ehdr, sizeof(Elf64_Ehdr), 1, infile);
    // gestion d'erreur
    if(infile==NULL)
    {
        perror("Une erreur est survenue lors de l'ouverture du fichier elf...");
        exit(5001);
    }   
    // afficher des 4 premier bytes.
    for(i=0; i<4; i++)
    {
        printf(" Ehdr.e_ident[%d]: 0x02%x\n", i, Ehdr.e_ident[i]);
    }
    
    // afficher le e_type
    printf("     Ehdr.e_type: 0x%02x ", Ehdr.e_type);
        
    switch (Ehdr.e_type)
    {
        case ET_NONE:   puts("(ET_NONE: No file type.)");
                break;
        case ET_REL:    puts("(ET_REL: Relocatable file.)");
                break;
        case ET_EXEC:   puts("(ET_EXEC: Executable file.)");
                break;
        case ET_DYN:    puts("(ET_DYN: Shared object file.)");  
                break;
        case ET_CORE:   puts("(ET_CORE: Core file.)");
                break;
        case ET_LOPROC: puts("(ET_LOPROC: Processor Specific.)");
                break;
        case ET_HIPROC: puts("(ET_HIPROC: Processor Specific.)");
                break;
        default:
                puts("Unknown type !");
    }
            
    // afficher la e_machine
    printf("  Ehdr.e_machine: 0x%02x ", Ehdr.e_machine);
    if ( Ehdr.e_machine == EM_X86_64 )
    {
        puts("(EM_X86_64: AMD x86-64)");
    }
    // afficher la version
    printf("  Ehdr.e_version: 0x%04x\n", Ehdr.e_version);
    
    printf("    Ehdr.e_entry: 0x%08lx\n", Ehdr.e_entry);
    printf("    Ehdr.e_phoff: 0x%08lx\n", Ehdr.e_phoff);
    printf("    Ehdr.e_shoff: 0x%08lx\n", Ehdr.e_shoff);
    printf("    Ehdr.e_flags: 0x%04x\n", Ehdr.e_flags);
    printf(" Ehdr.e_shstrndx: 0x%02x\n", Ehdr.e_shstrndx);
    printf("   Ehdr.e_ehsize: 0x%02x\n", Ehdr.e_ehsize);
    printf("Ehdr.e_phentsize: 0x%02x\n", Ehdr.e_phentsize);
    printf("    Ehdr.e_phnum: 0x%02x\n", Ehdr.e_phnum);
    printf("Ehdr.e_shentsize: 0x%02x\n", Ehdr.e_shentsize);
    printf("    Ehdr.e_shnum: 0x%02x\n", Ehdr.e_shnum);
    
    return(0);
}