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#!/usr/bin/python3 -tt
# Copyright 2013 Jussi Pakkanen
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import sys, struct
SHT_STRTAB = 3
DT_NEEDED = 1
DT_RPATH = 15
DT_STRTAB = 5
DT_SONAME = 14
class DynamicEntry():
def __init__(self, ifile):
self.d_tag = struct.unpack('Q', ifile.read(8))[0];
self.val = struct.unpack('Q', ifile.read(8))[0];
class SectionHeader():
def __init__(self, ifile):
#Elf64_Word
self.sh_name = struct.unpack('I', ifile.read(4))[0];
#Elf64_Word
self.sh_type = struct.unpack('I', ifile.read(4))[0]
#Elf64_Xword
self.sh_flags = struct.unpack('Q', ifile.read(8))[0];
#Elf64_Addr
self.sh_addr = struct.unpack('Q', ifile.read(8))[0];
#Elf64_Off
self.sh_offset = struct.unpack('Q', ifile.read(8))[0]
#Elf64_Xword
self.sh_size = struct.unpack('Q', ifile.read(8))[0];
#Elf64_Word
self.sh_link = struct.unpack('I', ifile.read(4))[0];
#Elf64_Word
self.sh_info = struct.unpack('I', ifile.read(4))[0];
#Elf64_Xword
self.sh_addralign = struct.unpack('Q', ifile.read(8))[0];
#Elf64_Xword
self.sh_entsize = struct.unpack('Q', ifile.read(8))[0];
class Elf():
def __init__(self, bfile):
self.bfile = bfile
self.bf = open(bfile, 'rb')
self.parse_header()
self.parse_sections()
self.parse_dynamic()
def parse_header(self):
self.e_ident = struct.unpack('16s', self.bf.read(16))[0]
if self.e_ident[1:4] != b'ELF':
raise RuntimeError('File "%s" is not an ELF file.' % self.bfile)
self.e_type = struct.unpack('h', self.bf.read(2))[0]
self.e_machine = struct.unpack('h', self.bf.read(2))[0]
self.e_version = struct.unpack('i', self.bf.read(4))[0]
self.e_entry = struct.unpack('Q', self.bf.read(8))[0]
self.e_phoff = struct.unpack('Q', self.bf.read(8))[0]
self.e_shoff = struct.unpack('Q', self.bf.read(8))[0]
self.e_flags = struct.unpack('i', self.bf.read(4))[0]
self.e_ehsize = struct.unpack('h', self.bf.read(2))[0]
self.e_phentsize = struct.unpack('h', self.bf.read(2))[0]
self.e_phnum = struct.unpack('h', self.bf.read(2))[0]
self.e_shentsize = struct.unpack('h', self.bf.read(2))[0]
self.e_shnum = struct.unpack('h', self.bf.read(2))[0]
self.e_shstrndx = struct.unpack('h', self.bf.read(2))[0]
def parse_sections(self):
self.bf.seek(self.e_shoff)
self.sections = []
for i in range(self.e_shnum):
self.sections.append(SectionHeader(self.bf))
def read_str(self):
arr = []
x = self.bf.read(1)
while x != b'\0':
arr.append(x)
x = self.bf.read(1)
if x == b'':
raise RuntimeError('Tried to read past the end of the file')
return b''.join(arr)
def find_section(self, target_name):
section_names = self.sections[self.e_shstrndx]
for i in self.sections:
self.bf.seek(section_names.sh_offset + i.sh_name)
name = self.read_str()
if name == target_name:
return i
def parse_dynamic(self):
sec = self.find_section(b'.dynamic')
self.dynamic = []
self.bf.seek(sec.sh_offset)
while True:
e = DynamicEntry(self.bf)
self.dynamic.append(e)
if e.d_tag == 0:
break
def print_section_names(self):
section_names = self.sections[self.e_shstrndx]
for i in self.sections:
self.bf.seek(section_names.sh_offset + i.sh_name)
name = self.read_str()
print(name.decode())
def print_soname(self):
soname = None
strtab = None
for i in self.dynamic:
if i.d_tag == DT_SONAME:
soname = i
if i.d_tag == DT_STRTAB:
strtab = i
self.bf.seek(strtab.val + soname.val)
print(self.read_str())
def print_deps(self):
sec = self.find_section(b'.dynstr')
deps = []
for i in self.dynamic:
if i.d_tag == DT_NEEDED:
deps.append(i)
for i in deps:
offset = sec.sh_offset + i.val
self.bf.seek(offset)
name = self.read_str()
print(name)
if __name__ == '__main__':
if len(sys.argv) != 2:
print('%s: <binary file>' % sys.argv[0])
exit(1)
e = Elf(sys.argv[1])
e.print_deps()
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