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Read_Elf.cpp
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Read_Elf.cpp
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#include "Read_Elf.h"
using namespace std;
FILE *file = NULL;
FILE *elf = NULL;
Elf64_Ehdr elf64_hdr;
char *shsttab = NULL;
char *strtab = NULL;
char *symtab = NULL;
ULL cOffset = 0;
ULL cSize = 0;
ULL cVadr = 0;
ULL dOffset = 0;
ULL dSize = 0;
ULL dVadr = 0;
ULL gp = 0;
ULL entry = 0;
ULL mainAddr = 0;
ULL mainSize = 0;
ULL textSize = 0;
ULL dataAddr = 0;
GlobalSymbol globalSymbol[100];
int symNum = 0;
// Program headers
static ULL padr = 0;
static unsigned short psize = 0;
static unsigned short pnum = 0;
// Section Headers
static ULL sadr = 0;
static unsigned short ssize = 0;
static unsigned short snum = 0;
// Symbol table
ULL symadr = 0;
static unsigned short symsize = 0;
static unsigned short symnum = 0;
bool open_file(string fname)
{
file = fopen(fname.c_str(), "r");
if (file == NULL)
return false;
char elfName[100] = {0};
sprintf(elfName, "%s.elf", fname.c_str());
elf = fopen(elfName, "w");
if (elf == NULL)
return false;
return true;
}
bool read_elf(string fname)
{
if (!open_file(fname))
return false;
fprintf(elf, "ELF Header:\n");
read_elf_header();
read_elf_shst();
fprintf(elf, "\n\nSection Headers:\n");
read_elf_sections();
read_elf_strtab();
fprintf(elf, "\n\nProgram Headers:\n");
read_elf_phdr();
fprintf(elf, "\n\nSymbol Table:\n");
read_elf_symtable();
fclose(elf);
return true;
}
void read_elf_header()
{
// file should be relocated
fseek(file, 0, SEEK_SET);
fread(&elf64_hdr, 1, sizeof(elf64_hdr), file);
fprintf(elf, " magic number: ");
for (int i = 0; i < EI_NIDENT; ++i)
fprintf(elf, " 0x%x", elf64_hdr.e_ident[i]);
fprintf(elf, "\n");
fprintf(elf, " Class: ");
switch (elf64_hdr.e_ident[EI_CLASS])
{
case 0:
fprintf(elf, "ELFCLASSNONE\n");
break;
case 1:
fprintf(elf, "ELFCLASS32\n");
break;
case 2:
fprintf(elf, "ELFCLASS64\n");
break;
default:
fprintf(elf, "\n");
}
fprintf(elf, " Data: ");
switch (elf64_hdr.e_ident[EI_DATA])
{
case 0:
fprintf(elf, "ELFDATANONE\n");
break;
case 1:
fprintf(elf, "ELFDATA2LSB\n");
break;
case 2:
fprintf(elf, "ELFDATA2MSB\n");
break;
default:
fprintf(elf, "\n");
}
fprintf(elf, " Version: 0x%x\n", elf64_hdr.e_ident[EI_VERSION]);
fprintf(elf, " OS/ABI: ");
switch (elf64_hdr.e_ident[EI_OSABI])
{
case 0x00:
fprintf(elf, "UNIX Syetem V\n");
break;
case 0x03:
fprintf(elf, "LINUX\n");
break;
case 0x06:
fprintf(elf, "Solaris\n");
break;
case 0x09:
fprintf(elf, "FreeBSD\n");
break;
default:
fprintf(elf, "Unknown\n");
break;
}
fprintf(elf, " ABI Version: 0x%x\n", elf64_hdr.e_ident[EI_ABIVERSION]);
fprintf(elf, " Type: ");
switch ((unsigned short)elf64_hdr.e_type)
{
case 0:
fprintf(elf, "ET_NONE\n");
break;
case 1:
fprintf(elf, "ET_REL\n");
break;
case 2:
fprintf(elf, "ET_EXEC\n");
break;
case 3:
fprintf(elf, "ET_DYN\n");
break;
case 4:
fprintf(elf, "ET_CORE\n");
break;
case 0xff00:
fprintf(elf, "ET_LOPROC\n");
break;
case 0xffff:
fprintf(elf, "ET_HIPROC\n");
break;
default:
fprintf(elf, "\n");
}
fprintf(elf, " Machine: ");
switch ((unsigned short)elf64_hdr.e_machine)
{
case 0:
fprintf(elf, "ET_NONE\n");
break;
case 1:
fprintf(elf, "EM_M32\n");
break;
case 2:
fprintf(elf, "EM_SPARC\n");
break;
case 3:
fprintf(elf, "EM_386\n");
break;
case 4:
fprintf(elf, "EM_68K\n");
break;
case 5:
fprintf(elf, "EM_88K\n");
break;
case 6:
fprintf(elf, "\n");
break;
case 7:
fprintf(elf, "EM_860\n");
break;
case 8:
fprintf(elf, "EM_MIPS\n");
break;
case 9:
fprintf(elf, "\n");
break;
case 10:
fprintf(elf, "EM_MIPS_RS4-BE\n");
break;
default:
fprintf(elf, "\n");
}
fprintf(elf, " Version: %d\n", (unsigned int)elf64_hdr.e_version);
fprintf(elf, " Entry point address: 0x%llx\n", (ULL)elf64_hdr.e_entry);
entry = (ULL)elf64_hdr.e_entry;
fprintf(elf, " Start of program headers: %lld bytes into file\n", (ULL)elf64_hdr.e_phoff);
padr = (ULL)elf64_hdr.e_phoff;
fprintf(elf, " Start of section headers: %lld bytes into file\n", (ULL)elf64_hdr.e_shoff);
sadr = (ULL)elf64_hdr.e_shoff;
fprintf(elf, " Flags: 0x%x\n", (unsigned int)elf64_hdr.e_flags);
fprintf(elf, " Size of this header: %hd Bytes\n", (unsigned short)elf64_hdr.e_ehsize);
fprintf(elf, " Size of program headers: %hd Bytes\n", (unsigned short)elf64_hdr.e_phentsize);
psize = (unsigned short)elf64_hdr.e_phentsize;
fprintf(elf, " Number of program headers: %hd\n", (unsigned short)elf64_hdr.e_phnum);
pnum = (unsigned short)elf64_hdr.e_phnum;
fprintf(elf, " Size of section headers: %hd Bytes\n", (unsigned short)elf64_hdr.e_shentsize);
ssize = (unsigned short)elf64_hdr.e_shentsize;
fprintf(elf, " Number of section headers: %hd\n", (unsigned short)elf64_hdr.e_shnum);
snum = (unsigned short)elf64_hdr.e_shnum;
fprintf(elf, " Section header string table index: %hd\n",
(unsigned short)elf64_hdr.e_shstrndx);
}
void read_elf_shst()
{
Elf64_Shdr shst_shdr;
fseek(file, sadr + elf64_hdr.e_shstrndx * ssize, SEEK_SET);
fread(&shst_shdr, 1, ssize, file);
shsttab = new char[(ULL)shst_shdr.sh_size + 100];
memset(shsttab, 0, (ULL)shst_shdr.sh_size + 100);
fseek(file, shst_shdr.sh_offset, SEEK_SET);
fread(shsttab, 1, (ULL)shst_shdr.sh_size, file);
}
void read_elf_sections()
{
Elf64_Shdr elf64_shdr;
fseek(file, sadr, SEEK_SET);
for (int c = 0; c < snum; c++)
{
fprintf(elf, "[%3d]", c);
// file should be relocated
fread(&elf64_shdr, 1, sizeof(elf64_shdr), file);
fprintf(elf, " Name: %s", (char *)(shsttab + (unsigned int)elf64_shdr.sh_name));
if (strcmp((char *)(shsttab + (unsigned int)elf64_shdr.sh_name), ".data") == 0)
{
dataAddr = (ULL)elf64_shdr.sh_addr;
}
fprintf(elf, " Type: ");
switch ((unsigned int)elf64_shdr.sh_type)
{
case 0:
fprintf(elf, "SHT_NULL");
break;
case 1:
fprintf(elf, "SHT_PROGBITS");
break;
case 2:
fprintf(elf, "SHT_SYMTAB");
symadr = (ULL)elf64_shdr.sh_offset;
symsize = (unsigned short)elf64_shdr.sh_size;
symnum = symsize / sizeof(Elf64_Sym);
break;
case 3:
fprintf(elf, "SHT_STRTAB");
break;
case 4:
fprintf(elf, "SHT_RELA");
break;
case 5:
fprintf(elf, "SHT_HASH");
break;
case 6:
fprintf(elf, "SHT_DYNAMIC");
break;
case 7:
fprintf(elf, "SHT_NOTE");
break;
case 8:
fprintf(elf, "SHT_NOBITS");
break;
case 9:
fprintf(elf, "SHT_REL");
break;
case 10:
fprintf(elf, "SHT_SHLIB");
break;
case 11:
fprintf(elf, "SHT_DYNSYM");
break;
case 0x70000000:
fprintf(elf, "SHT_LOPROC");
break;
case 0x7fffffff:
fprintf(elf, "SHT_HIPROC");
break;
case 0x80000000:
fprintf(elf, "SHT_LOUSER");
break;
case 0xffffffff:
fprintf(elf, "SHT_HIUSER");
break;
default:
break;
}
fprintf(elf, " Address: 0x%llx", (ULL)elf64_shdr.sh_addr);
fprintf(elf, " Offest: %lld", (ULL)elf64_shdr.sh_offset);
fprintf(elf, " Size: %lld", (ULL)elf64_shdr.sh_size);
fprintf(elf, " Entsize: %lld", (ULL)elf64_shdr.sh_entsize);
fprintf(elf, " Flags: ");
switch (elf64_shdr.sh_flags)
{
case 0x1:
fprintf(elf, "SHF_WRITE");
break;
case 0x2:
fprintf(elf, "SHF_ALLOC");
break;
case 0x4:
fprintf(elf, "SHF_EXECINSTR");
break;
case 0xf0000000:
fprintf(elf, "SHF_MASHPROC");
break;
default:
break;
}
fprintf(elf, " Link: %d", (unsigned int)elf64_shdr.sh_link);
fprintf(elf, " Info: %d", (unsigned int)elf64_shdr.sh_info);
fprintf(elf, " Align: %lld", (ULL)elf64_shdr.sh_addralign);
fprintf(elf, "\n");
}
}
void read_elf_strtab()
{
Elf64_Shdr elf64_shdr;
fseek(file, sadr, SEEK_SET);
for (int c = 0; c < snum; c++)
{
fread(&elf64_shdr, 1, sizeof(elf64_shdr), file);
if ((unsigned int)elf64_shdr.sh_type == 3 &&
strcmp((char *)(shsttab + (unsigned int)elf64_shdr.sh_name), ".strtab") == 0)
{
strtab = new char[(ULL)elf64_shdr.sh_size + 100];
memset(strtab, 0, (ULL)elf64_shdr.sh_size + 100);
fseek(file, (ULL)elf64_shdr.sh_offset, SEEK_SET);
fread(strtab, 1, (ULL)elf64_shdr.sh_size, file);
}
else if ((unsigned int)elf64_shdr.sh_type == 1 &&
strcmp((char *)(shsttab + (unsigned int)elf64_shdr.sh_name), ".text") == 0)
{
textSize = (ULL)elf64_shdr.sh_size;
}
}
}
void read_elf_phdr()
{
Elf64_Phdr elf64_phdr;
fseek(file, padr, SEEK_SET);
for (int c = 0; c < pnum; c++)
{
fprintf(elf, "[%3d]", c);
// file should be relocated
fread(&elf64_phdr, 1, sizeof(elf64_phdr), file);
fprintf(elf, " Type: ");
switch (elf64_phdr.p_type)
{
case 0:
fprintf(elf, "PT_NULL");
break;
case 1:
fprintf(elf, "PT_LOAD");
break;
case 2:
fprintf(elf, "PT_DYNAMIC");
break;
case 3:
fprintf(elf, "PT_INTERP");
break;
case 4:
fprintf(elf, "PT_NOTE");
break;
case 5:
fprintf(elf, "PT_SHLIB");
break;
case 6:
fprintf(elf, "PT_PHDR");
break;
case 0x70000000:
fprintf(elf, "PT_LOPROC");
break;
case 0x7fffffff:
fprintf(elf, "PT_HIPROC");
break;
default:
break;
}
fprintf(elf, " Flags: ");
switch ((unsigned int)elf64_phdr.p_flags)
{
case 1:
fprintf(elf, "X");
break;
case 2:
fprintf(elf, "W");
break;
case 3:
fprintf(elf, "WX");
break;
case 4:
fprintf(elf, "R");
break;
case 5:
fprintf(elf, "RX");
if (elf64_phdr.p_type == 1)
{
cOffset = (ULL)elf64_phdr.p_offset;
cSize = (ULL)elf64_phdr.p_filesz;
cVadr = (ULL)elf64_phdr.p_vaddr;
}
break;
case 6:
fprintf(elf, "RW");
if (elf64_phdr.p_type == 1)
{
dOffset = (ULL)elf64_phdr.p_offset;
dSize = elf64_phdr.p_filesz;
dVadr = (ULL)elf64_phdr.p_vaddr;
}
break;
case 7:
fprintf(elf, "RWX");
if (elf64_phdr.p_type == 1)
{
cOffset = (ULL)elf64_phdr.p_offset;
cSize = (ULL)elf64_phdr.p_filesz;
cVadr = (ULL)elf64_phdr.p_vaddr;
}
break;
default:
fprintf(elf, "U");
break;
}
fprintf(elf, " Offset: %lld", (ULL)elf64_phdr.p_offset);
fprintf(elf, " VirtAddr: 0x%llx", (ULL)elf64_phdr.p_vaddr);
fprintf(elf, " PhysAddr: 0x%llx", (ULL)elf64_phdr.p_paddr);
fprintf(elf, " FileSiz: %lld", (ULL)elf64_phdr.p_filesz);
fprintf(elf, " MemSiz: %lld", (ULL)elf64_phdr.p_memsz);
fprintf(elf, " Align: %lld", (ULL)elf64_phdr.p_align);
fprintf(elf, "\n");
}
}
void read_elf_symtable()
{
Elf64_Sym elf64_sym;
symNum = 0;
fseek(file, symadr, SEEK_SET);
for (int c = 0; c < symnum; c++)
{
fprintf(elf, "[%3d]", c);
// file should be relocated
fread(&elf64_sym, 1, sizeof(elf64_sym), file);
fprintf(elf, " Name: %s", (char *)(strtab + (unsigned int)elf64_sym.st_name));
if (strcmp((char *)(strtab + (unsigned int)elf64_sym.st_name), "_gp") == 0)
{
gp = elf64_sym.st_value;
}
if (strcmp((char *)(strtab + (unsigned int)elf64_sym.st_name), "__global_pointer$") ==
0)
{
gp = elf64_sym.st_value;
}
if (strcmp((char *)(strtab + (unsigned int)elf64_sym.st_name), "main") == 0)
{
mainAddr = elf64_sym.st_value;
mainSize = elf64_sym.st_size;
}
fprintf(elf, " Bind: ");
switch (ELF64_ST_BIND(elf64_sym.st_info))
{
case 0:
fprintf(elf, "STB_LOCAL");
break;
case 1:
fprintf(elf, "STB_GLOBAL");
break;
case 2:
fprintf(elf, "STB_WEAK");
break;
case 13:
fprintf(elf, "STB_LOPROC");
break;
case 15:
fprintf(elf, "STB_HIPROC");
break;
default:
break;
}
fprintf(elf, " Type: ");
switch (ELF64_ST_TYPE(elf64_sym.st_info))
{
case 0:
fprintf(elf, "STT_NOTYPE");
break;
case 1:
fprintf(elf, "STT_OBJECT");
break;
case 2:
fprintf(elf, "STT_FUNC");
break;
case 3:
fprintf(elf, "STT_SECTION");
break;
case 4:
fprintf(elf, "STT_FILE");
break;
case 13:
fprintf(elf, "STT_LOPROC");
break;
case 15:
fprintf(elf, "STT_HIPROC");
break;
default:
break;
}
if ((ELF64_ST_BIND(elf64_sym.st_info) == 1) &&
(ELF64_ST_TYPE(elf64_sym.st_info) == 1) &&
*((char *)(strtab + (unsigned int)elf64_sym.st_name)) != '_')
{
sprintf(globalSymbol[symNum].name, "%s",
(char *)(strtab + (unsigned int)elf64_sym.st_name));
globalSymbol[symNum].addr = elf64_sym.st_value;
globalSymbol[symNum].size = elf64_sym.st_size;
symNum++;
}
fprintf(elf, " NDX: %hd", (unsigned short)elf64_sym.st_shndx);
fprintf(elf, " Size: %lld", (ULL)elf64_sym.st_size);
fprintf(elf, " Value: 0x%llx", (ULL)elf64_sym.st_value);
fprintf(elf, "\n");
}
}