karlphillip karlphillip - 4 months ago 303
C Question

readelf-like tool for Mac OS X?

Is there a tool for reading Mac OS X binaries that would print information about relocation tables and symbol offsets similar to this

readelf
output?

readelf -r app

Relocation section '.rel.dyn' at offset 0x5ec contains 2 entries:
Offset Info Type Sym.Value Sym. Name
08049d58 00001706 R_386_GLOB_DAT 00000000 __gmon_start__
08049d60 00000305 R_386_COPY 08049d60 _ZSt4cout

Relocation section '.rel.plt' at offset 0x5fc contains 13 entries:
Offset Info Type Sym.Value Sym. Name
08049d24 00000107 R_386_JUMP_SLOT 0804868c print
08049d28 00000207 R_386_JUMP_SLOT 0804869c _ZNSt8ios_base4InitC1E
08049d2c 00000507 R_386_JUMP_SLOT 080486ac _ZStlsISt11char_traits
08049d30 00000607 R_386_JUMP_SLOT 080486bc _ZNSolsEPFRSoS_E
08049d34 00000707 R_386_JUMP_SLOT 08048664 _init
08049d38 00000807 R_386_JUMP_SLOT 080486dc sleep
08049d3c 00000907 R_386_JUMP_SLOT 080486ec _ZNKSsixEj
08049d40 00000b07 R_386_JUMP_SLOT 080486fc _ZNKSs4sizeEv
08049d44 00000c07 R_386_JUMP_SLOT 0804870c __libc_start_main
08049d48 00000d07 R_386_JUMP_SLOT 08048ae4 _fini
08049d4c 00001307 R_386_JUMP_SLOT 0804872c _ZSt4endlIcSt11char_tr
08049d50 00001507 R_386_JUMP_SLOT 0804873c __gxx_personality_v0
08049d54 00001607 R_386_JUMP_SLOT 0804874c _ZNSt8ios_base4InitD1E


In this example,
print
is a function loaded from a shared library (I wrote) at runtime.
readelf
is able to display information about its location inside the
app
binary.

Answer

Using Macports:

  1. Install macports.
  2. Using macports port install binutils
  3. gobjdump -p /path/to/app

Using Homebrew:

  1. Install Homebrew
  2. Do brew update && brew install binutils
  3. gobjdump -p /path/to/app

There are, of course, many other command-line options. Note that the binutils port cautions that installing it may cause other ports to fail to build. Having it around to port install/look at something/port uninstall can still be handy.

It's rather amazing that there isn't already some native tool to do this.