Class: Indis::MachO::DyldInfoParser

Inherits:
Object
  • Object
show all
Defined in:
lib/indis-macho/dyld_info_parser.rb

Constant Summary collapse

BIND_OPCODE_MASK = 
0xF0
BIND_IMMEDIATE_MASK = 
0x0F
BIND_OPCODES = 
{
  0x00 => :BIND_OPCODE_DONE,
  0x10 => :BIND_OPCODE_SET_DYLIB_ORDINAL_IMM,
  0x20 => :BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB,
  0x30 => :BIND_OPCODE_SET_DYLIB_SPECIAL_IMM,
  0x40 => :BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM,
  0x50 => :BIND_OPCODE_SET_TYPE_IMM,
  0x60 => :BIND_OPCODE_SET_ADDEND_SLEB,
  0x70 => :BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB,
  0x80 => :BIND_OPCODE_ADD_ADDR_ULEB,
  0x90 => :BIND_OPCODE_DO_BIND,
  0xA0 => :BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB,
  0xB0 => :BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED,
  0xC0 => :BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB,
}
TYPE_IMM = 
{
  1 => :POINTER,
  2 => :TEXT_ABSOLUTE32,
  3 => :TEXT_PCREL32,
}

Instance Method Summary collapse

Constructor Details

#initialize(bytes) ⇒ DyldInfoParser

Returns a new instance of DyldInfoParser.



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# File 'lib/indis-macho/dyld_info_parser.rb', line 50

def initialize(bytes)
  @bytes = StringIO.new(bytes)
end

Instance Method Details

#parse ⇒ Object 



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# File 'lib/indis-macho/dyld_info_parser.rb', line 54

def parse
  syms = []
  sym = {offset: 0}
  begin
    
    b = pop
    opcode = BIND_OPCODES[b & BIND_OPCODE_MASK]
    imm = b & BIND_IMMEDIATE_MASK
    #puts "** OPCODE #{opcode} IMM #{imm}"
    case opcode
    when :BIND_OPCODE_SET_DYLIB_ORDINAL_IMM
      sym[:library] = imm
    when :BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM
      sym[:flags] = []
      sym[:flags] << :WEAK_IMPORT if imm & 1 == 1
      sym[:flags] << :NON_WEAK_DEFINITION if imm & 8 == 8
      
      nm = ''
      c = pop
      while c != 0 do
        nm += c.chr
        c = pop
      end
      sym[:name] = nm
    when :BIND_OPCODE_SET_TYPE_IMM
      #puts "Unknown type #{imm}" unless TYPE_IMM[imm]
      sym[:type] = TYPE_IMM[imm] || imm
    when :BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB
      sym[:segment] = imm
      sym[:offset] = pop_uleb
    when :BIND_OPCODE_DONE
      #break
    when :BIND_OPCODE_DO_BIND
      syms << sym.dup
      sym[:offset] += 4
    when :BIND_OPCODE_ADD_ADDR_ULEB
      u = pop_uleb
      sym[:offset] += u
    when :BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED
      syms << sym.dup
      sym[:offset] += 4 + imm*4
    when :BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB
      count = pop_uleb
      skip  = pop_uleb
      count.times do
        syms << sym.dup
        sym[:offset] += skip + 4
      end
    else
      raise "unknown opcode #{opcode} #{(b & BIND_OPCODE_MASK).to_s 16}"
    end
    sym[:offset] &= 0xffffffff
  end while @bytes.pos < @bytes.length
  syms
end