From 7d4e4c0b34a613dd3c0220475ae4e448197522c1 Mon Sep 17 00:00:00 2001
From: Treeki <treeki@gmail.com>
Date: Sat, 12 Mar 2011 23:17:12 +0100
Subject: initial commit. now I can start playing with stuff!

---
 tools/hooks.py | 166 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 166 insertions(+)
 create mode 100755 tools/hooks.py

(limited to 'tools/hooks.py')

diff --git a/tools/hooks.py b/tools/hooks.py
new file mode 100755
index 0000000..13c4e19
--- /dev/null
+++ b/tools/hooks.py
@@ -0,0 +1,166 @@
+import binascii
+import struct
+
+u32 = struct.Struct('>I')
+
+def make_branch_insn(fromAddr, toAddr, branchType):
+	branchTypes = ['b', 'bl', 'ba', 'bla']
+	if branchType not in branchTypes:
+		raise ValueError, 'invalid branch type: %s' % branchType
+	
+	extra = branchTypes.index(branchType)
+	
+	distance = toAddr - fromAddr
+	if distance >= 0x2000000 or distance <= -0x2000000:
+		raise ValueError, 'branching too far: %08x to %08x' % (fromAddr, toAddr)
+	
+	return (distance & 0x3FFFFFC) | 0x48000000 | extra
+
+
+
+class HookContext(object):
+	"""Object which can be used by each hook type to hold data."""
+	
+	def __init__(self):
+		self.hooks = []
+
+
+
+class Hook(object):
+	"""Generic hook class"""
+	
+	has_context = False
+	required_data = []
+	
+	def __init__(self, builder, module, data):
+		"""Sets up a hook"""
+		self.builder = builder
+		self.module = module
+		self.data = data
+		
+		if self.has_context:
+			hookType = type(self)
+			self.context = builder._hook_contexts[hookType]
+			self.context.hooks.append(self)
+		
+		# validate the hook's data
+		current_config_name = builder._config_short_name
+		
+		for field in self.required_data:
+			field = field.replace('%CONFIG%', current_config_name)
+			if field not in data:
+				raise ValueError, 'hook %s : %s is missing the field %s' % (module.moduleName, data['name'], field)
+	
+	def create_patches(self):
+		pass
+
+
+
+class BasicPatchHook(Hook):
+	"""Hook that simply patches data to an address"""
+	
+	required_data = ['addr_%CONFIG%', 'data']
+	
+	def __init__(self, builder, module, data):
+		Hook.__init__(self, builder, module, data)
+	
+	def create_patches(self):
+		addr = self.data['addr_%s' % self.builder._config_short_name]
+		
+		hex_data = self.data['data']
+		
+		whitespace = ' \n\r\t'
+		for char in whitespace:
+			hex_data = hex_data.replace(char, '')
+		
+		patch = binascii.unhexlify(hex_data)
+		
+		self.builder._add_patch(addr, patch)
+
+
+
+class BranchInsnHook(Hook):
+	"""Hook that replaces the instruction at a specific address with a branch"""
+	
+	required_data = ['branch_type', 'src_addr_%CONFIG%']
+	
+	def __init__(self, builder, module, data):
+		Hook.__init__(self, builder, module, data)
+	
+	def create_patches(self):
+		try:
+			target_func = self.data['target_func']
+		except KeyError:
+			target_func = self.data['target_func_%s' % self.builder._config_short_name]
+		
+		if isinstance(target_func, str):
+			target_func = self.builder._find_func_by_symbol(target_func)
+		else:
+			# assume it's an address
+			pass
+		
+		
+		src_addr = self.data['src_addr_%s' % self.builder._config_short_name]
+		branch_insn = make_branch_insn(src_addr, target_func, self.data['branch_type'])
+		
+		self.builder._add_patch(src_addr, u32.pack(branch_insn))
+
+
+
+class AddFunctionPointerHook(Hook):
+	"""Hook that places a function pointer at an address"""
+	
+	required_data = ['src_addr_%CONFIG%']
+	
+	def __init__(self, builder, module, data):
+		Hook.__init__(self, builder, module, data)
+	
+	def create_patches(self):
+		try:
+			target_func = self.data['target_func']
+		except KeyError:
+			target_func = self.data['target_func_%s' % self.builder._config_short_name]
+		
+		if isinstance(target_func, str):
+			target_func = self.builder._find_func_by_symbol(target_func)
+		else:
+			# assume it's an address
+			pass
+		
+		
+		src_addr = self.data['src_addr_%s' % self.builder._config_short_name]
+		
+		self.builder._add_patch(src_addr, u32.pack(target_func))
+
+
+
+class NopInsnHook(Hook):
+	"""Hook that NOPs out the instruction(s) at an address"""
+	
+	required_data = ['area_%CONFIG%']
+	
+	def __init__(self, builder, module, data):
+		Hook.__init__(self, builder, module, data)
+	
+	def create_patches(self):
+		area = self.data['area_%s' % self.builder._config_short_name]
+		
+		if isinstance(area, list):
+			addr, end = area
+			count = (end + 4 - addr) / 4
+			nop_patch = '\x60\x00\x00\x00' * count
+		else:
+			addr = area
+			nop_patch = '\x60\x00\x00\x00'
+		
+		self.builder._add_patch(addr, nop_patch)
+
+
+
+HookTypes = {
+	'patch': BasicPatchHook,
+	'branch_insn': BranchInsnHook,
+	'add_func_pointer': AddFunctionPointerHook,
+	'nop_insn': NopInsnHook,
+}
+
-- 
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