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Code: added code for other tasks
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8 files changed

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8 files changed

+433
-1
lines changed

‎0x15-file_io/100-elf_header.c

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#include <elf.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdio.h>
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#include <stdlib.h>
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void check_elf(unsigned char *e_ident);
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void print_magic(unsigned char *e_ident);
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void print_class(unsigned char *e_ident);
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void print_data(unsigned char *e_ident);
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void print_version(unsigned char *e_ident);
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void print_abi(unsigned char *e_ident);
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void print_osabi(unsigned char *e_ident);
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void print_type(unsigned int e_type, unsigned char *e_ident);
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void print_entry(unsigned long int e_entry, unsigned char *e_ident);
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void close_elf(int elf);
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/**
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* check_elf - Checks if a file is an ELF file.
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* @e_ident: A pointer to an array containing the ELF magic numbers.
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*
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* Description: If the file is not an ELF file - exit code 98.
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*/
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void check_elf(unsigned char *e_ident)
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{
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int index;
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for (index = 0; index < 4; index++)
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{
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if (e_ident[index] != 127 &&
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e_ident[index] != 'E' &&
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e_ident[index] != 'L' &&
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e_ident[index] != 'F')
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{
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dprintf(STDERR_FILENO, "Error: Not an ELF file\n");
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exit(98);
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}
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}
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}
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/**
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* print_magic - Prints the magic numbers of an ELF header.
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* @e_ident: A pointer to an array containing the ELF magic numbers.
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*
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* Description: Magic numbers are separated by spaces.
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*/
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void print_magic(unsigned char *e_ident)
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{
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int index;
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printf(" Magic: ");
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for (index = 0; index < EI_NIDENT; index++)
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{
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printf("%02x", e_ident[index]);
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if (index == EI_NIDENT - 1)
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printf("\n");
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else
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printf(" ");
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}
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}
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/**
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* print_class - Prints the class of an ELF header.
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* @e_ident: A pointer to an array containing the ELF class.
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*/
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void print_class(unsigned char *e_ident)
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{
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printf(" Class: ");
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switch (e_ident[EI_CLASS])
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{
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case ELFCLASSNONE:
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printf("none\n");
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break;
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case ELFCLASS32:
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printf("ELF32\n");
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break;
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case ELFCLASS64:
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printf("ELF64\n");
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break;
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default:
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printf("<unknown: %x>\n", e_ident[EI_CLASS]);
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}
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}
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/**
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* print_data - Prints the data of an ELF header.
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* @e_ident: A pointer to an array containing the ELF class.
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*/
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void print_data(unsigned char *e_ident)
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{
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printf(" Data: ");
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switch (e_ident[EI_DATA])
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{
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case ELFDATANONE:
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printf("none\n");
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break;
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case ELFDATA2LSB:
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printf("2's complement, little endian\n");
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break;
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case ELFDATA2MSB:
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printf("2's complement, big endian\n");
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break;
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default:
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printf("<unknown: %x>\n", e_ident[EI_CLASS]);
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}
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}
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/**
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* print_version - Prints the version of an ELF header.
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* @e_ident: A pointer to an array containing the ELF version.
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*/
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void print_version(unsigned char *e_ident)
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{
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printf(" Version: %d",
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e_ident[EI_VERSION]);
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switch (e_ident[EI_VERSION])
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{
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case EV_CURRENT:
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printf(" (current)\n");
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break;
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default:
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printf("\n");
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break;
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}
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}
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/**
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* print_osabi - Prints the OS/ABI of an ELF header.
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* @e_ident: A pointer to an array containing the ELF version.
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*/
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void print_osabi(unsigned char *e_ident)
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{
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printf(" OS/ABI: ");
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switch (e_ident[EI_OSABI])
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{
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case ELFOSABI_NONE:
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printf("UNIX - System V\n");
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break;
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case ELFOSABI_HPUX:
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printf("UNIX - HP-UX\n");
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break;
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case ELFOSABI_NETBSD:
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printf("UNIX - NetBSD\n");
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break;
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case ELFOSABI_LINUX:
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printf("UNIX - Linux\n");
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break;
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case ELFOSABI_SOLARIS:
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printf("UNIX - Solaris\n");
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break;
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case ELFOSABI_IRIX:
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printf("UNIX - IRIX\n");
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break;
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case ELFOSABI_FREEBSD:
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printf("UNIX - FreeBSD\n");
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break;
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case ELFOSABI_TRU64:
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printf("UNIX - TRU64\n");
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break;
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case ELFOSABI_ARM:
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printf("ARM\n");
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break;
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case ELFOSABI_STANDALONE:
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printf("Standalone App\n");
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break;
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default:
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printf("<unknown: %x>\n", e_ident[EI_OSABI]);
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}
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}
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/**
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* print_abi - Prints the ABI version of an ELF header.
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* @e_ident: A pointer to an array containing the ELF ABI version.
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*/
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void print_abi(unsigned char *e_ident)
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{
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printf(" ABI Version: %d\n",
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e_ident[EI_ABIVERSION]);
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}
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/**
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* print_type - Prints the type of an ELF header.
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* @e_type: The ELF type.
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* @e_ident: A pointer to an array containing the ELF class.
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*/
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void print_type(unsigned int e_type, unsigned char *e_ident)
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{
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if (e_ident[EI_DATA] == ELFDATA2MSB)
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e_type >>= 8;
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printf(" Type: ");
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switch (e_type)
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{
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case ET_NONE:
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printf("NONE (None)\n");
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break;
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case ET_REL:
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printf("REL (Relocatable file)\n");
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break;
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case ET_EXEC:
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printf("EXEC (Executable file)\n");
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break;
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case ET_DYN:
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printf("DYN (Shared object file)\n");
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break;
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case ET_CORE:
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printf("CORE (Core file)\n");
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break;
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default:
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printf("<unknown: %x>\n", e_type);
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}
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}
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/**
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* print_entry - Prints the entry point of an ELF header.
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* @e_entry: The address of the ELF entry point.
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* @e_ident: A pointer to an array containing the ELF class.
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*/
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void print_entry(unsigned long int e_entry, unsigned char *e_ident)
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{
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printf(" Entry point address: ");
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if (e_ident[EI_DATA] == ELFDATA2MSB)
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{
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e_entry = ((e_entry << 8) & 0xFF00FF00) |
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((e_entry >> 8) & 0xFF00FF);
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e_entry = (e_entry << 16) | (e_entry >> 16);
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}
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if (e_ident[EI_CLASS] == ELFCLASS32)
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printf("%#x\n", (unsigned int)e_entry);
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else
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printf("%#lx\n", e_entry);
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}
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/**
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* close_elf - Closes an ELF file.
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* @elf: The file descriptor of the ELF file.
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*
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* Description: If the file cannot be closed - exit code 98.
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*/
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void close_elf(int elf)
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{
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if (close(elf) == -1)
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{
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dprintf(STDERR_FILENO,
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"Error: Can't close fd %d\n", elf);
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exit(98);
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}
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}
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/**
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* main - Displays the information contained in the
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* ELF header at the start of an ELF file.
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* @argc: The number of arguments supplied to the program.
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* @argv: An array of pointers to the arguments.
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*
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* Return: 0 on success.
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*
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* Description: If the file is not an ELF File or
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* the function fails - exit code 98.
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*/
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int main(int __attribute__((__unused__)) argc, char *argv[])
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{
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Elf64_Ehdr *header;
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int o, r;
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o = open(argv[1], O_RDONLY);
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if (o == -1)
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{
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dprintf(STDERR_FILENO, "Error: Can't read file %s\n", argv[1]);
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exit(98);
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}
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header = malloc(sizeof(Elf64_Ehdr));
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if (header == NULL)
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{
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close_elf(o);
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dprintf(STDERR_FILENO, "Error: Can't read file %s\n", argv[1]);
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exit(98);
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}
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r = read(o, header, sizeof(Elf64_Ehdr));
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if (r == -1)
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{
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free(header);
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close_elf(o);
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dprintf(STDERR_FILENO, "Error: `%s`: No such file\n", argv[1]);
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exit(98);
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}
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check_elf(header->e_ident);
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printf("ELF Header:\n");
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print_magic(header->e_ident);
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print_class(header->e_ident);
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print_data(header->e_ident);
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print_version(header->e_ident);
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print_osabi(header->e_ident);
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print_abi(header->e_ident);
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print_type(header->e_type, header->e_ident);
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print_entry(header->e_entry, header->e_ident);
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free(header);
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close_elf(o);
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return (0);
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}

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