Class: ApkResources

Inherits:
Object
  • Object
show all
Defined in:
lib/apktools/apkresources.rb

Overview

Class to parse an APK’s resources.arsc data and retrieve resource data associated with a given R.id value

Defined Under Namespace

Classes: ChunkHeader, PackageHeader, ResType, ResTypeConfig, ResTypeEntry, ResTypeSpec, StringPool

Constant Summary collapse

DEBUG =

:nodoc:

false

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(apk_file) ⇒ ApkResources

Create a new ApkResources instance from the specified apk_file

This opens and parses the contents of the APK’s resources.arsc file.



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# File 'lib/apktools/apkresources.rb', line 128

def initialize(apk_file)
	data = nil		
	# Get resources.arsc from the APK file
	Zip::ZipFile.foreach(apk_file) do |f|
	  if f.name.match(/resources.arsc/)
		data = f.get_input_stream.read
	  end
	end
	
	# Parse the Table Chunk
	## Header
	header_type = read_short(data, HEADER_START)
	header_size = read_short(data, HEADER_START+2)
	header_chunk_size = read_word(data, HEADER_START+4)
	header_package_count = read_word(data, HEADER_START+8)
	puts "Resource Package Count = #{header_package_count}" if DEBUG
	if header_package_count > 1
		puts "ApkResources only supports single package resources."
		exit(1)
	end
	
	# Parse the StringPool Chunk
	## Header
	startoffset_pool = HEADER_START + header_size
	puts "Parse Main StringPool Chunk" if DEBUG
	@stringpool_main = parse_stringpool(data, startoffset_pool)
	puts "#{@stringpool_main.values.length} strings found" if DEBUG
	
	# Parse the Package Chunk
	## Header
	startoffset_package = startoffset_pool + @stringpool_main.header.chunk_size
	header = ChunkHeader.new( read_short(data, startoffset_package),
			read_short(data, startoffset_package+2),
			read_word(data, startoffset_package+4) )
	
	package_id = read_word(data, startoffset_package+8)
	package_name = read_string(data, startoffset_package+12, 256, "UTF-8")
	package_type_strings = read_word(data, startoffset_package+268)
	package_last_type = read_word(data, startoffset_package+272)
	package_key_strings = read_word(data, startoffset_package+276)
	package_last_key = read_word(data, startoffset_package+280)
	
	@package_header = PackageHeader.new(header, package_id, package_name, package_type_strings, package_key_strings)
	
	## typeStrings StringPool
	startoffset_typestrings = startoffset_package + package_type_strings
	puts "Parse typeStrings StringPool Chunk" if DEBUG
	@stringpool_typestrings = parse_stringpool(data, startoffset_typestrings)
	
	## keyStrings StringPool
	startoffset_keystrings = startoffset_package + package_key_strings
	puts "Parse keyStrings StringPool Chunk" if DEBUG
	@stringpool_keystrings = parse_stringpool(data, startoffset_keystrings)
	
	## typeSpec/type Chunks		
	@type_data = Array.new()
	current_spec = nil
	
	current = startoffset_keystrings + @stringpool_keystrings.header.chunk_size
	puts "Parse Type/TypeSpec Chunks" if DEBUG
	while current < data.length
		## Parse Header
		header = ChunkHeader.new( read_short(data, current),
				read_short(data, current+2),
				read_word(data, current+4) )
		## Check Type
		if header.type == CHUNKTYPE_TYPESPEC
			typespec_id = read_byte(data, current+8)
			typespec_entrycount = read_word(data, current+12)
			
			## Parse the config flags for each entry
			typespec_entries = Array.new()
			i=0
			while i < typespec_entrycount
				offset = i * 4 + (current+16)
				typespec_entries << read_word(data, offset)
				
				i += 1
			end
			
			typespec_name = @stringpool_typestrings.values[typespec_id - 1]
			current_spec = ResTypeSpec.new(header, typespec_name, typespec_entrycount, typespec_entries, nil)
			
			@type_data << current_spec
			current += header.chunk_size
		elsif header.type == CHUNKTYPE_TYPE
			type_id = read_byte(data, current+8)
			type_entrycount = read_word(data, current+12) 
			type_entryoffset = read_word(data, current+16)

			## The config flags set for this type chunk
			## TODO: Vary the size of the config structure based on size to accomodate for new flags
			config_size = read_word(data, current+20) # Number of bytes in structure
			type_config = ResTypeConfig.new( read_word(data, current+24),
					read_word(data, current+28),
					read_word(data, current+32),
					read_word(data, current+36 ),
					read_word(data, current+40),
					read_word(data, current+44),
					read_word(data, current+48),
					read_word(data, current+52) )

			## The remainder of the chunk is a list of the entry values for that type/configuration
			type_name = @stringpool_typestrings.values[type_id - 1]				
			if current_spec.types == nil
				current_spec.types = ResType.new(header, type_name, type_config, type_entrycount, Array.new())
			end

			i=0
			while i < type_entrycount
				## Ensure a hash exists for each type
				if current_spec.types.entries[i] == nil
					current_spec.types.entries[i] = Hash.new()
				end
				current_entry = current_spec.types.entries[i]

				## Get the start of the type from the offsets table
				index_offset = i * 4 + (current+56)
				start_offset = read_word(data, index_offset)
				if start_offset != OFFSET_NO_ENTRY
					## Set the index_offset to the start of the current entry
					index_offset = current + type_entryoffset + start_offset

					entry_flags = read_short(data, index_offset+2)
					entry_key = read_word(data, index_offset+4)
					entry_data_type = read_byte(data, index_offset+11)
					entry_data = read_word(data, index_offset+12)
					
					# Find the key in our strings index
					key_name = @stringpool_keystrings.values[entry_key]
					# Parse the value into a string
					data_value = nil
					case type_name
						when TYPE_STRING, TYPE_DRAWABLE
							data_value = get_resource_string(entry_data_type, entry_data)
						when TYPE_COLOR
							data_value = get_resource_color(entry_data_type, entry_data)
						when TYPE_DIMENSION
							data_value = get_resource_dimension(entry_data_type, entry_data)
						when TYPE_INTEGER
							data_value = get_resource_integer(entry_data_type, entry_data)
						when TYPE_BOOLEAN
							data_value = get_resource_bool(entry_data_type, entry_data)
						else
							puts "Complex Resources not yet supported." if DEBUG
							data_value = entry_data.to_s
					end
					current_entry[type_config] = ResTypeEntry.new(entry_flags, key_name, entry_data_type, data_value)
				end
				i += 1
			end
			
			current += header.chunk_size
		else
			puts "Unknown Chunk Found: #{header.type} #{header.size}" if DEBUG
			## End Immediately
			current = data.length
		end
	end
	
end

Instance Attribute Details

#package_header ⇒ Object (readonly)

PackageHeader containing information about all the type and key strings in the package



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# File 'lib/apktools/apkresources.rb', line 113

def package_header
  @package_header
end

#stringpool_keystrings ⇒ Object (readonly)

StringPool containing all key strings in the package



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# File 'lib/apktools/apkresources.rb', line 119

def stringpool_keystrings
  @stringpool_keystrings
end

#stringpool_main ⇒ Object (readonly)

StringPool containing all value strings in the package



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# File 'lib/apktools/apkresources.rb', line 115

def stringpool_main
  @stringpool_main
end

#stringpool_typestrings ⇒ Object (readonly)

StringPool containing all type strings in the package



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# File 'lib/apktools/apkresources.rb', line 117

def stringpool_typestrings
  @stringpool_typestrings
end

#type_data ⇒ Object (readonly)

Array of the ResTypeSpec chunks in the package



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# File 'lib/apktools/apkresources.rb', line 121

def type_data
  @type_data
end

Instance Method Details

#get_all_keys ⇒ Object

Return array of all the key values in the file



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# File 'lib/apktools/apkresources.rb', line 307

def get_all_keys
	return @stringpool_keystrings.values
end

#get_all_strings ⇒ Object

Return array of all string values in the file



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# File 'lib/apktools/apkresources.rb', line 293

def get_all_strings
	return @stringpool_main.values
end

#get_all_types ⇒ Object

Return array of all the type values in the file



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# File 'lib/apktools/apkresources.rb', line 300

def get_all_types
	return @stringpool_typestrings.values
end

#get_default_resource_value(res_id) ⇒ Object

Obtain the default value for a given resource id

res_id: ID values of a resources as a FixNum or String representation (i.e. 0x7F060001)

Returns: The default ResTypeEntry to the given id, or nil if no default exists



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# File 'lib/apktools/apkresources.rb', line 358

def get_default_resource_value(res_id)
	if res_id.is_a? String
		res_id = res_id.hex
	end
	
	entries = get_resource_value(res_id)
	if entries != nil
		default = ResTypeConfig.new(0, 0, 0, 0, 0, 0, 0, 0)
		default_entry = entries[default]
		return default_entry
	else
		return nil
	end
end

#get_resource_key(res_id, xml_format = false) ⇒ Object

Obtain the key value for a given resource id

res_id: ID value of a resource as a FixNum or String representation (i.e. 0x7F060001) xml_format: Optionally format return string for XML files.

If xml_format is true, return value will be @<type>/<key> If xml_format is false or missing, return value will be R.<type>.<key> If the resource id does not exist, return value will be nil



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# File 'lib/apktools/apkresources.rb', line 321

def get_resource_key(res_id, xml_format=false)
	if res_id.is_a? String
		res_id = res_id.hex
	end
	
	# R.id integers are a concatenation of package_id, type_id, and entry index
	res_package = (res_id >> 24) & 0xFF
	res_type = (res_id >> 16) & 0xFF
	res_index = res_id & 0xFFFF

	if res_package != @package_header.id
		# This is not a resource we can parse
		return nil
	end
	
	res_spec = @type_data[res_type-1]
	entry = res_spec.types.entries[res_index]
	
	if entry == nil
		# There is no entry in our table for this resource
		return nil
	end
	
	if xml_format
		return "@#{res_spec.id}/#{entry.values[0].key}"
	else
		return "R.#{res_spec.id}.#{entry.values[0].key}"
	end
end

#get_resource_value(res_id) ⇒ Object

Obtain the value(s) for a given resource id. A default resource is one defined in an unqualified directory.

res_id: ID value of a resource as a FixNum or String representation (i.e. 0x7F060001)

Returns: Hash of all entries matching this id, keyed by their matching ResTypeConfig or nil if the resource id cannot be found.



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# File 'lib/apktools/apkresources.rb', line 382

def get_resource_value(res_id)
	if res_id.is_a? String
		res_id = res_id.hex
	end
	
	# R.id integers are a concatenation of package_id, type_id, and entry index
	res_package = (res_id >> 24) & 0xFF
	res_type = (res_id >> 16) & 0xFF
	res_index = res_id & 0xFFFF

	if res_package != @package_header.id
		# This is not a resource we can parse
		return nil
	end
	
	res_spec = @type_data[res_type-1]
	
	entries = res_spec.types.entries[res_index]
	if entries == nil
		puts "Could not find #{type_name} ResType chunk" if DEBUG
		return nil
	end
	
	return entries
end