1 #!/usr/bin/env python
2 # SPDX-License-Identifier: GPL-2.0
3 # libxed.py: Python wrapper for libxed.so
4 # Copyright (c) 2014-2021, Intel Corporation.
5 
6 # To use Intel XED, libxed.so must be present. To build and install
7 # libxed.so:
8 #            git clone https://github.com/intelxed/mbuild.git mbuild
9 #            git clone https://github.com/intelxed/xed
10 #            cd xed
11 #            ./mfile.py --share
12 #            sudo ./mfile.py --prefix=/usr/local install
13 #            sudo ldconfig
14 #
15 
16 import sys
17 
18 from ctypes import CDLL, Structure, create_string_buffer, addressof, sizeof, \
19 		   c_void_p, c_bool, c_byte, c_char, c_int, c_uint, c_longlong, c_ulonglong
20 
21 # XED Disassembler
22 
23 class xed_state_t(Structure):
24 
25 	_fields_ = [
26 		("mode", c_int),
27 		("width", c_int)
28 	]
29 
30 class XEDInstruction():
31 
32 	def __init__(self, libxed):
33 		# Current xed_decoded_inst_t structure is 192 bytes. Use 512 to allow for future expansion
34 		xedd_t = c_byte * 512
35 		self.xedd = xedd_t()
36 		self.xedp = addressof(self.xedd)
37 		libxed.xed_decoded_inst_zero(self.xedp)
38 		self.state = xed_state_t()
39 		self.statep = addressof(self.state)
40 		# Buffer for disassembled instruction text
41 		self.buffer = create_string_buffer(256)
42 		self.bufferp = addressof(self.buffer)
43 
44 class LibXED():
45 
46 	def __init__(self):
47 		try:
48 			self.libxed = CDLL("libxed.so")
49 		except:
50 			self.libxed = None
51 		if not self.libxed:
52 			self.libxed = CDLL("/usr/local/lib/libxed.so")
53 
54 		self.xed_tables_init = self.libxed.xed_tables_init
55 		self.xed_tables_init.restype = None
56 		self.xed_tables_init.argtypes = []
57 
58 		self.xed_decoded_inst_zero = self.libxed.xed_decoded_inst_zero
59 		self.xed_decoded_inst_zero.restype = None
60 		self.xed_decoded_inst_zero.argtypes = [ c_void_p ]
61 
62 		self.xed_operand_values_set_mode = self.libxed.xed_operand_values_set_mode
63 		self.xed_operand_values_set_mode.restype = None
64 		self.xed_operand_values_set_mode.argtypes = [ c_void_p, c_void_p ]
65 
66 		self.xed_decoded_inst_zero_keep_mode = self.libxed.xed_decoded_inst_zero_keep_mode
67 		self.xed_decoded_inst_zero_keep_mode.restype = None
68 		self.xed_decoded_inst_zero_keep_mode.argtypes = [ c_void_p ]
69 
70 		self.xed_decode = self.libxed.xed_decode
71 		self.xed_decode.restype = c_int
72 		self.xed_decode.argtypes = [ c_void_p, c_void_p, c_uint ]
73 
74 		self.xed_format_context = self.libxed.xed_format_context
75 		self.xed_format_context.restype = c_uint
76 		self.xed_format_context.argtypes = [ c_int, c_void_p, c_void_p, c_int, c_ulonglong, c_void_p, c_void_p ]
77 
78 		self.xed_tables_init()
79 
80 	def Instruction(self):
81 		return XEDInstruction(self)
82 
83 	def SetMode(self, inst, mode):
84 		if mode:
85 			inst.state.mode = 4 # 32-bit
86 			inst.state.width = 4 # 4 bytes
87 		else:
88 			inst.state.mode = 1 # 64-bit
89 			inst.state.width = 8 # 8 bytes
90 		self.xed_operand_values_set_mode(inst.xedp, inst.statep)
91 
92 	def DisassembleOne(self, inst, bytes_ptr, bytes_cnt, ip):
93 		self.xed_decoded_inst_zero_keep_mode(inst.xedp)
94 		err = self.xed_decode(inst.xedp, bytes_ptr, bytes_cnt)
95 		if err:
96 			return 0, ""
97 		# Use AT&T mode (2), alternative is Intel (3)
98 		ok = self.xed_format_context(2, inst.xedp, inst.bufferp, sizeof(inst.buffer), ip, 0, 0)
99 		if not ok:
100 			return 0, ""
101 		if sys.version_info[0] == 2:
102 			result = inst.buffer.value
103 		else:
104 			result = inst.buffer.value.decode()
105 		# Return instruction length and the disassembled instruction text
106 		# For now, assume the length is in byte 166
107 		return inst.xedd[166], result
108