elf changelog

Changelog History

• v0.30 Changes

  December 26, 2018

  parseSymbolTables now parses SHT_DYNSYM in addition to SHT_SYMTAB

• v0.29 Changes

  June 19, 2018

  • ➕ Add few more test cases
  • ✂ remove call to deprecated functions in binary

• v0.28 Changes

  February 23, 2017

  Hi list,

  ✅ with below test program:

  🏗 ​/* test1.c: build with -g -O0 */
  include <stdio.h>

  static const char appmsg[] = "hello, world";

  int main(int argc, char* argv[])
  {
  fputs(appmsg, stdout);

      return 0;
  

  }

  --- ✅ elf-test1.hs
  module Main where

  ✅ import qualified Data.ByteString as B
  ✅ import qualified Data.ByteString.Char8 as C

  import Control.Monad

  import Data.Elf

  ✅ testelf = "/tmp/test1"
  ✅ testelfsym = C.pack "appmsg"

  lookupSymbol1 _ [] = Nothing
  lookupSymbol1 sym (t:ts) =
  case (snd (steName t)) of
  Nothing -> lookupSymbol1 sym ts
  Just sname -> if sname == sym then Just t
  else lookupSymbol1 sym ts

  lookupSymbol _ [] = Nothing
  lookupSymbol sym (t:ts) =
  case (lookupSymbol1 sym t) of
  Nothing -> lookupSymbol sym ts
  t1 -> t1

  ✅ test1 elf symtab symbol = mapM_ (print) (elfSections elf)

  ✅ test2 elf symtab symbol =
  lookupSymbol symbol symtab

  ✅ test3 elf symtab symbol =
  lookupSymbol symbol symtab >>= \et ->
  findSymbolDefinition et

  mainloop elf symtab symbol =
  -- ✅ (test1 elf symtab symbol) >>
  ✅ print (test2 elf symtab symbol) >>
  ✅ print (test3 elf symtab symbol) >>
  return ()

  main = do
  ✅ contents <- B.readFile testelf
  👀 let elf = parseElf contents
  📜 symtab = parseSymbolTables elf

  ✅ mainloop elf symtab testelfsym

  ✅ the latest Data.Elf doesn't geive correct output as expected:

  output will be:

  Just (EST {steName = (9,Just "appmsg"), steEnclosingSection = Just (ElfSection {elfSectionName = ".fini", elfSectionType = SHT_PROGBITS, elfSectionFlags = [SHF_EXECINSTR,SHF_ALLOC], elfSectionAddr = 4195908, elfSectionSize = 9, elfSectionLink = 0, elfSectionInfo = 0, elfSectionAddrAlign = 4, elfSectionEntSize = 0, elfSectionData = "H\131\236\bH\131\196\b\195"}), steType = STTObject, steBind = STBLocal, steOther = 0, steIndex = SHNIndex 14, steValue = 4195924, steSize = 13})

  👀 From above, you can see the steEnclosingSection is wrong and offset by 1.

  The correct output should be:
  Just (EST {steName = (9,Just "appmsg"), steEnclosingSection = Just (ElfSection {elfSectionName = ".rodata", elfSectionType = SHT_PROGBITS, elfSectionFlags = [SHF_ALLOC], elfSectionAddr = 4195920, elfSectionSize = 17, elfSectionLink = 0, elfSectionInfo = 0, elfSectionAddrAlign = 4, elfSectionEntSize = 0, elfSectionData = "\SOH\NUL\STX\NULhello, world\NUL"}), steType = STTObject, steBind = STBLocal, steOther = 0, steIndex = SHNIndex 14, steValue = 4195924, steSize = 13})
  Just "hello, world\NUL"

  After check Elf.hs, I found there could be two issues:

  1. in sectionByIndex, (SHNIndex) should start from 0, not 1; this cause the steEnclosingSection from my exmaple offset by 1;
  2. in findSymbolDefinition, start should substract the sectionAddr (base address).

• v0.27 Changes

  February 23, 2017

  🚀 This release is exactly the same as v0.27 from hackage (https://hackage.haskell.org/package/elf).
  📦 The package is no longer exist in github (by Erik Charlebois), thus (re-)creating this repo for maintaining purpose.