changeset 118:db8aafe00d27

Added elf file read scripts
author Windel Bouwman
date Sat, 12 Jan 2013 09:39:23 +0100
parents f2b37d78082d
children f51791638cae
files python/elffile.py python/readelf.py
diffstat 2 files changed, 85 insertions(+), 0 deletions(-) [+]
line wrap: on
line diff
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/elffile.py	Sat Jan 12 09:39:23 2013 +0100
@@ -0,0 +1,68 @@
+import struct
+
+classes = {1:'ELF32', 2:'ELF64'}
+
+class ElfFile:
+   def __init__(self, f):
+      self.f = f
+      self.parse()
+   def parse(self):
+      self.parseHeader()
+      self.parseSections()
+      self.parsePrograms()
+   @property
+   def ElfClass(self):
+      return classes[self.ei_class]
+   def parseHeader(self):
+      # Parse identifier
+      e_ident = self.f.read(16)
+      ELFMAGIC = bytes([0x7f]) + b'ELF'
+      assert e_ident[0:4] == ELFMAGIC
+      self.ei_class = e_ident[4]
+      print('ELF class: ', self.ElfClass)
+      assert self.ei_class in classes.keys()
+      self.ei_data = e_ident[5]
+      print('ei_data:', self.ei_data)
+      ei_version = e_ident[6]
+      assert ei_version == 1
+
+      # rest of the ELF header:
+      e_type = self.readHalf()
+      e_machine = self.readHalf()
+      e_version = self.readWord()
+      e_entry = self.readAddr()
+      e_phoff = self.readOff()
+      e_shoff = self.readOff()
+      e_flags = self.readWord()
+      e_ehsize = self.readHalf()
+      e_phentsize = self.readHalf()
+      e_phnum = self.readHalf()
+      e_shentsize = self.readHalf()
+      e_shnum = self.readHalf()
+      e_shstrndx = self.readHalf()
+      
+      if self.ei_class == 1:
+         assert e_ehsize == 52
+      elif self.ei_class == 2:
+         assert e_ehsize == 64
+      print('program header size', e_phentsize, e_phnum)
+      print('section header size', e_shentsize, e_shnum, e_shstrndx)
+   def readFmt(self, fmt):
+      size = struct.calcsize(fmt)
+      return struct.unpack(fmt, self.f.read(size))
+   def readHalf(self):
+      return self.readFmt('<H')[0]
+   def readWord(self):
+      return self.readFmt('<I')[0]
+   def readAddr(self):
+      if self.ei_class == 1:
+         fmt = '<I'
+      elif self.ei_class == 2:
+         fmt = '<Q'
+      else:
+         raise Exception()
+      return self.readFmt(fmt)[0]
+   readOff = readAddr
+
+   def printProgramHeaders(self):
+      pass
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/readelf.py	Sat Jan 12 09:39:23 2013 +0100
@@ -0,0 +1,17 @@
+#!/usr/bin/python
+
+import elffile, argparse
+
+parser = argparse.ArgumentParser()
+parser.add_argument('file', type=argparse.FileType('rb'))
+parser.add_argument('-l', action='store_const', const=True, default=False, dest='list_program_headers')
+
+args = parser.parse_args()
+print(args)
+ef = elffile.ElfFile(args.file)
+print(ef)
+
+if args.list_program_headers:
+   print('program headers')
+   ef.printProgramHeaders()
+