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
16import sys
17
18from 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
23class xed_state_t(Structure):
24
25	_fields_ = [
26		("mode", c_int),
27		("width", c_int)
28	]
29
30class 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
44class 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