objc_rt_class_dump

This is a small amount of code that uses the Objective-C Runtime functions to dump a program's Objective-C class information when injected into a running process via GDB.

Building

For iOS: make

For OS X: PLATFORM=osx make

Usage

1. Build the library:

    $ PLATFORM=osx make
   

2. Attach GDB to a running process:

    $ gdb -p `pidof stickies`
    GNU gdb 6.3.50-20050815 (Apple version gdb-1824) (Thu Nov 15 10:42:43 UTC 2012)
    Copyright 2004 Free Software Foundation, Inc.
    GDB is free software, covered by the GNU General Public License, and you are
    welcome to change it and/or distribute copies of it under certain conditions.
    Type "show copying" to see the conditions.
    There is absolutely no warranty for GDB.  Type "show warranty" for details.
    This GDB was configured as "x86_64-apple-darwin".
    /Users/ggironda/Repositories/gdb/28760: No such file or directory
    Attaching to process 28760.
    Reading symbols for shared libraries . done
    Reading symbols for shared libraries ...................................................................................................................................................................................... done
    Reading symbols for shared libraries + done
    0x00007fff8a36e686 in mach_msg_trap ()
    (gdb)
   

3. Load the library:

    $ ls
    Makefile            README.md           obj_c_rt_util.c     obj_c_rt_util.c.o   obj_c_rt_util.dylib
    $ pwd
    /Users/ggironda/Repositories/objc_rt_class_dump
    
    (gdb) call (void *) dlopen("/Users/ggironda/Repositories/objc_rt_class_dump/objc_rt_class_dump.dylib")
   

4. Check /tmp for the output:

    $ grep NSThemeFrameTitleTextField -A20 /tmp/obj_c_rt_util.txt
    NSThemeFrameTitleTextField
      Methods
        dealloc
        isFlipped
        setFrameOrigin:
        drawRect:
        _windowChangedKeyState
        setAttributedStringValue:
        attributedStringValue
        canSmoothFontsInLayer
        invalidateOnFrameOriginChange
        setInvalidateOnFrameOriginChange:
      Properties
        attributedStringValue
        invalidateOnFrameOriginChange
    _NSKeyedUnarchiverHelper
      Methods
        allowedClassNames
        setAllowedClassNames:
        classNameAllowed:
        init