Versuch einer readelf implementation. funzt noch nicht os doll

This commit is contained in:
madmaurice 2016-11-14 19:02:42 +01:00
parent 5d25d48945
commit 027facd857
1 changed files with 275 additions and 0 deletions

275
elfheader.c Normal file
View File

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#include <stdio.h>
#define BOOL int
#define true 1
#define false 0
#define ARCH32 1
#define ARCH64 2
#define ENDIANLITTLE 1
#define ENDIANBIG 2
#define ABI_UNDEFINED 0x00
#define ABI_HP_UX 0x01
#define ABI_NETBSD 0x02
#define ABI_LINUX 0x03
#define ABI_SOLARIS 0x06
#define ABI_AIX 0x07
#define ABI_IRIX 0x08
#define ABI_FREEBSD 0x09
#define ABI_OPENBSD 0x0C
#define ABI_OPENVMS 0x0D
#define ABI_NONSTOP_KERNEL 0x0E
#define ABI_AROS 0x0F
#define ABI_FENIX 0x10
#define ABI_CLOUDABI 0x11
#define ABI_SORTIX 0x53
#define TYPE_RELOCATABLE 1
#define TYPE_EXECUTABLE 2
#define TYPE_SHARED 3
#define TYPE_CORE 4
#define ISA_UNDEFINED 0x00
#define ISA_SPARC 0x02
#define ISA_X86 0x03
#define ISA_MIPS 0x08
#define ISA_POWERPC 0x14
#define ISA_ARM 0x28
#define ISA_SUPERH 0x2A
#define ISA_IA64 0x32
#define ISA_X86_64 0x3E
#define ISA_AARCH64 0xB7
unsigned char freadbyte(FILE* fd) {
unsigned char byte;
fread(&byte,1,1,fd);
return byte;
}
void fskip(FILE* fd, int num) {
fseek(fd, num, SEEK_CUR);
}
long freadword(FILE* fd, int arch) {
long word = 0;
if(arch == 64) {
word += (long)freadbyte(fd) << 56;
word += (long)freadbyte(fd) << 48;
word += (long)freadbyte(fd) << 40;
word += (long)freadbyte(fd) << 32;
}
word += (long)freadbyte(fd) << 24;
word += (long)freadbyte(fd) << 16;
word += (long)freadbyte(fd) << 8;
word += (long)freadbyte(fd);
return word;
}
BOOL check_magicnum(FILE* fd) {
if(freadbyte(fd) != 0x7F) return false;
if(freadbyte(fd) != 'E') return false;
if(freadbyte(fd) != 'L') return false;
if(freadbyte(fd) != 'F') return false;
return true;
}
short get_arch(FILE* fd) {
unsigned char byte = freadbyte(fd);
if(byte == ARCH32) {
printf("Arch: 32 bit\n");
} else if(byte == ARCH64) {
printf("Arch: 64 bit\n");
} else {
printf("Arch: unknown\n");
}
return byte;
}
void get_endian(FILE* fd) {
unsigned char byte = freadbyte(fd);
if(byte == ENDIANLITTLE) {
printf("Endian: Little\n");
} else if(byte == ENDIANBIG) {
printf("Endian: Big\n");
} else {
printf("Endian: Unknown\n");
}
}
void get_version(FILE* fd) {
unsigned char byte = freadbyte(fd);
printf("ELF-Version: %X\n",byte);
}
void get_abi(FILE* fd) {
unsigned char abi = freadbyte(fd);
printf("ABI: ");
switch(abi) {
case ABI_UNDEFINED:
printf("Not specified");
break;
case ABI_HP_UX:
printf("HP-UX");
break;
case ABI_NETBSD:
printf("NetBSD");
break;
case ABI_LINUX:
printf("Linux");
break;
case ABI_SOLARIS:
printf("Solaris");
break;
case ABI_AIX:
printf("AIX");
break;
case ABI_IRIX:
printf("IRIX");
break;
case ABI_FREEBSD:
printf("FreeBSD");
break;
case ABI_OPENBSD:
printf("OpenBSD");
break;
case ABI_OPENVMS:
printf("OpenVMS");
break;
case ABI_NONSTOP_KERNEL:
printf("NonStop Kernel");
break;
case ABI_AROS:
printf("AROS");
break;
case ABI_FENIX:
printf("Fenix OS");
break;
case ABI_CLOUDABI:
printf("CloudABI");
break;
case ABI_SORTIX:
printf("Sortix");
break;
default:
printf("Unknown");
break;
}
printf("\n");
}
void get_type(FILE* fd) {
unsigned char type = freadbyte(fd);
printf("ELF Type: ");
switch(type) {
case TYPE_RELOCATABLE:
printf("Relocatable");
break;
case TYPE_EXECUTABLE:
printf("Executable");
break;
case TYPE_SHARED:
printf("Shared");
break;
case TYPE_CORE:
printf("Core");
break;
default:
printf("unknown");
break;
}
printf("\n");
}
void get_machine(FILE* fd) {
unsigned char machine = freadbyte(fd);
printf("ISA: ");
switch(machine) {
case ISA_UNDEFINED:
printf("Undefined");
break;
case ISA_SPARC:
printf("Sparc");
break;
case ISA_X86:
printf("x86");
break;
case ISA_MIPS:
printf("MIPS");
break;
case ISA_POWERPC:
printf("PowerPC");
break;
case ISA_ARM:
printf("ARM");
break;
case ISA_SUPERH:
printf("SuperH");
break;
case ISA_IA64:
printf("IA-64");
break;
case ISA_X86_64:
printf("x86_64");
break;
case ISA_AARCH64:
printf("AArch64");
break;
default:
printf("Unknown");
break;
}
printf("\n");
}
void get_entry_point(FILE* fd, int arch) {
long epoint = freadword(fd,arch);
printf("Entry Point: 0x%X\n",epoint);
}
void get_program_header(FILE* fd, int arch) {
long phoff = freadword(fd,arch);
printf("Program Header: 0x%X\n",phoff);
}
void get_section_header(FILE* fd, int arch) {
long shoff = freadword(fd,arch);
printf("Section Header: 0x%X\n",shoff);
}
void read_elf(FILE* fd) {
short arch = get_arch(fd);
get_endian(fd);
get_version(fd);
get_abi(fd);
fskip(fd,8);
get_type(fd);
get_machine(fd);
fskip(fd,4);
get_entry_point(fd,arch);
get_program_header(fd,arch);
get_section_header(fd,arch);
}
int main( int argc, char *argv[] ) {
if(argc <= 1) {
printf("Usage: %s <exacutable>\n",argv[0]);
return 1;
}
char* filename = argv[1];
FILE* fd = fopen(filename,"rb");
if(!check_magicnum(fd)) {
printf("Error: not a ELF-File\n");
} else {
printf("-- ELF Format detected\n");
read_elf(fd);
}
fclose(fd);
return 0;
}