python解析elf文件

#!/usr/bin/python
import struct 
import sys
elfhdr = {}
def verify_elf(filename):
	f = open(filename,'rb')
	elfident = f.read(16)
	magic = [ord(i) for i in elfident]
	if( magic[0] != 127 or magic[1]!= ord('E') or magic[2] != ord('L') or magic[3] != ord('F')):
		print "your input file %s not a elf file" %filename
		return
	else:
		temp = f.read(struct.calcsize('2HI3QI6H'))
		temp = struct.unpack('2HI3QI6H',temp)
		global elfhdr
		elfhdr['magic'] = magic
		elfhdr['e_type']= temp[0]
		elfhdr['e_machine'] = temp[1]
 		elfhdr['e_version'] = temp[2]
		elfhdr['e_entry'] = temp[3]
		elfhdr['e_phoff'] = temp[4]
		elfhdr['e_shoff'] = temp[5]
		elfhdr['e_flags'] = temp[6]
		elfhdr['e_ehsize'] = temp[7]
		elfhdr['e_phentsize'] = temp[8]
		elfhdr['e_phnum'] = temp[9]
		elfhdr['e_shentsize'] = temp[10]
		elfhdr['e_shnum'] = temp[11]
		elfhdr['e_shstrndx'] = temp[12]
	f.close()
def display_elfhdr(elffile):
	global elfhdr
	print "ELF Header"
	magic = elfhdr['magic']
	print "  Magic:  %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d" %(magic[0] ,magic[1],magic[2],magic[3],magic[4],magic[5],magic[6],magic[7],magic[8],magic[9],magic[10],magic[11],magic[12],magic[13],magic[14],magic[15])
	if magic[4] == 1 :
		print "  Class:                           ELF32"
	else:
		print "  Class:                           ELF64"
        if magic[5] == 1:
		print "  Data:                            2's complement,little endian"
	else:
		print "Data:                              2's complement,bigendian"
	print "  Version:                         %d(current)" %magic[6]
	if magic[7] == 0:
		os_abi = 'System V ABI'
	elif magic[7]== 1:
		os_abi = 'HP-Ux operating system'
	elif magic[7] == 255:
		os_abi = 'Standalone (embedded) application'
	print "  OS/ABI:                          %s" %os_abi
	print "  ABI Version:                     %d" %magic[8]
	if elfhdr['e_type'] == 0:
		type = 'No file type'
	elif elfhdr['e_type'] == 1:
		type = 'Relocatable object file'
	elif elfhdr['e_type'] == 2:
		type = 'Executable file'
	elif elfhdr['e_type'] == 3:
		type = 'Core file'
	print "  Type:                            %s" %type
	print "  Machine:                         %d" %elfhdr['e_machine']
	print "  Version:                         0x%x" %elfhdr['e_version']
	print "  Entry point address:             0x%x" %elfhdr['e_entry']
	print "  Start of program headers:        %d (bytes into file)" %elfhdr['e_phoff']
	print "  Start of section headers:        %d (bytes into file)" %elfhdr['e_shoff']
	print "  Flags:                           0x%x" %elfhdr['e_flags']
	print "  Size of this header:             %d (bytes)" %elfhdr['e_ehsize']
	print "  Size of program headers:         %d (bytes)" %elfhdr['e_phentsize']
	print "  Number of program headers:       %d " %elfhdr['e_phnum']
	print "  Size of section headers:         %d (bytes)" %elfhdr['e_shentsize']
	print "  Number of section headers:       %d" %elfhdr['e_shnum']
	print "  Section header string table index: %d"%elfhdr['e_shstrndx']
def display_sections(elffile):
    verify_elf(elffile)
    sections = []
    global elfhdr
    sec_start = elfhdr['e_shoff']
    sec_size = elfhdr['e_shentsize']
    f = open(elffile,'rb')
    f.seek(sec_start)
    for i in range(0,elfhdr['e_shnum']):
        temp = f.read(sec_size)
        temp = struct.unpack('2I4Q2I2Q',temp)
        sec = {}
        sec['sh_name'] = temp[0]
        sec['sh_type'] = temp[1]
        sec['sh_flags'] = temp[2]
        sec['sh_addr'] = temp[3]
        sec['sh_offset'] = temp[4]
        sec['sh_size'] = temp[5]
        sec['sh_link'] = temp[6]
        sec['sh_info'] = temp[7]
        sec['sh_addralign'] = temp[8]
        sec['sh_entsize'] = temp[9]
        sections.append(sec)
    print "There are %d section headers,starting at offset 0x%x:\n" %(elfhdr['e_shnum'],sec_start)
    print "Section Headers:"
    print "  [Nr] Name               Type            Address          Offset"
    print "       Size               Entsize         Flags  Link  Info Align"
    start = sections[elfhdr['e_shstrndx']]['sh_offset']
        for i in range(0,elfhdr['e_shnum']):
        offset = start + sections[i]['sh_name']
        name = get_name(f,offset)
        type2str = ['NULL','PROGBITS','SYMTAB','STRTAB','RELA','HASH','DYNAMIC','NOTE','NOBITS','REL','SHLIB','DYNSYM']
        flags = sections[i]['sh_flags']
        if (flags == 1):
            flagsstr = 'W'
        elif (flags == 2):
            flagsstr = 'A'
        elif (flags == 4):
            flagsstr = 'X'
        elif (flags == 3):
            flagsstr = 'W' + 'A'
        elif (flags == 6):
            flagsstr = 'A' +  'X'
        elif (flags == 0x0f000000 or flags == 0xf0000000):
            flagsstr = 'MS'
        else:
            flagsstr = ''
        print "  [%d]  %s              %s             %x             %x" %(i,name,type2str[sections[i]['sh_type'] & 0x7],sections[i]['sh_addr'],sections[i]['sh_addralign'])
        print "      %x                   %x       %s        %d     %d     %x" %(sections[i]['sh_size'],sections[i]['sh_entsize'],flagsstr,sections[i]['sh_link'],sections[i]['sh_info'],sections[i]['sh_addralign'])
    f.close()
def get_name(f,offset):
    name = ''
    f.seek(offset)
    while 1:
        c = f.read(1)
        if c == '\0':
            break
        else:
            name += c
    return name

if __name__ == '__main__':
file = sys.argv[1]
verify_elf(file)
display_elfhdr(file)
display_sections(file)

未完待续