1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
|
#!/usr/bin/python
# GDB debugging support
#
# Copyright 2012 Red Hat, Inc. and/or its affiliates
#
# Authors:
# Avi Kivity <avi@redhat.com>
#
# This work is licensed under the terms of the GNU GPL, version 2. See
# the COPYING file in the top-level directory.
#
# Contributions after 2012-01-13 are licensed under the terms of the
# GNU GPL, version 2 or (at your option) any later version.
import gdb
def isnull(ptr):
return ptr == gdb.Value(0).cast(ptr.type)
def int128(p):
return long(p['lo']) + (long(p['hi']) << 64)
def get_fs_base():
'''Fetch %fs base value using arch_prctl(ARCH_GET_FS)'''
# %rsp - 120 is scratch space according to the SystemV ABI
old = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)')
gdb.execute('call arch_prctl(0x1003, $rsp - 120)', False, True)
fs_base = gdb.parse_and_eval('*(uint64_t*)($rsp - 120)')
gdb.execute('set *(uint64_t*)($rsp - 120) = %s' % old, False, True)
return fs_base
def get_glibc_pointer_guard():
'''Fetch glibc pointer guard value'''
fs_base = get_fs_base()
return gdb.parse_and_eval('*(uint64_t*)((uint64_t)%s + 0x30)' % fs_base)
def glibc_ptr_demangle(val, pointer_guard):
'''Undo effect of glibc's PTR_MANGLE()'''
return gdb.parse_and_eval('(((uint64_t)%s >> 0x11) | ((uint64_t)%s << (64 - 0x11))) ^ (uint64_t)%s' % (val, val, pointer_guard))
def bt_jmpbuf(jmpbuf):
'''Backtrace a jmpbuf'''
JB_RBX = 0
JB_RBP = 1
JB_R12 = 2
JB_R13 = 3
JB_R14 = 4
JB_R15 = 5
JB_RSP = 6
JB_PC = 7
old_rbx = gdb.parse_and_eval('(uint64_t)$rbx')
old_rbp = gdb.parse_and_eval('(uint64_t)$rbp')
old_rsp = gdb.parse_and_eval('(uint64_t)$rsp')
old_r12 = gdb.parse_and_eval('(uint64_t)$r12')
old_r13 = gdb.parse_and_eval('(uint64_t)$r13')
old_r14 = gdb.parse_and_eval('(uint64_t)$r14')
old_r15 = gdb.parse_and_eval('(uint64_t)$r15')
old_rip = gdb.parse_and_eval('(uint64_t)$rip')
pointer_guard = get_glibc_pointer_guard()
gdb.execute('set $rbx = %s' % jmpbuf[JB_RBX])
gdb.execute('set $rbp = %s' % glibc_ptr_demangle(jmpbuf[JB_RBP], pointer_guard))
gdb.execute('set $rsp = %s' % glibc_ptr_demangle(jmpbuf[JB_RSP], pointer_guard))
gdb.execute('set $r12 = %s' % jmpbuf[JB_R12])
gdb.execute('set $r13 = %s' % jmpbuf[JB_R13])
gdb.execute('set $r14 = %s' % jmpbuf[JB_R14])
gdb.execute('set $r15 = %s' % jmpbuf[JB_R15])
gdb.execute('set $rip = %s' % glibc_ptr_demangle(jmpbuf[JB_PC], pointer_guard))
gdb.execute('bt')
gdb.execute('set $rbx = %s' % old_rbx)
gdb.execute('set $rbp = %s' % old_rbp)
gdb.execute('set $rsp = %s' % old_rsp)
gdb.execute('set $r12 = %s' % old_r12)
gdb.execute('set $r13 = %s' % old_r13)
gdb.execute('set $r14 = %s' % old_r14)
gdb.execute('set $r15 = %s' % old_r15)
gdb.execute('set $rip = %s' % old_rip)
class QemuCommand(gdb.Command):
'''Prefix for QEMU debug support commands'''
def __init__(self):
gdb.Command.__init__(self, 'qemu', gdb.COMMAND_DATA,
gdb.COMPLETE_NONE, True)
class CoroutineCommand(gdb.Command):
'''Display coroutine backtrace'''
def __init__(self):
gdb.Command.__init__(self, 'qemu coroutine', gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
def invoke(self, arg, from_tty):
argv = gdb.string_to_argv(arg)
if len(argv) != 1:
gdb.write('usage: qemu coroutine <coroutine-pointer>\n')
return
coroutine_pointer = gdb.parse_and_eval(argv[0]).cast(gdb.lookup_type('CoroutineUContext').pointer())
bt_jmpbuf(coroutine_pointer['env']['__jmpbuf'])
class MtreeCommand(gdb.Command):
'''Display the memory tree hierarchy'''
def __init__(self):
gdb.Command.__init__(self, 'qemu mtree', gdb.COMMAND_DATA,
gdb.COMPLETE_NONE)
self.queue = []
def invoke(self, arg, from_tty):
self.seen = set()
self.queue_root('address_space_memory')
self.queue_root('address_space_io')
self.process_queue()
def queue_root(self, varname):
ptr = gdb.parse_and_eval(varname)['root']
self.queue.append(ptr)
def process_queue(self):
while self.queue:
ptr = self.queue.pop(0)
if long(ptr) in self.seen:
continue
self.print_item(ptr)
def print_item(self, ptr, offset = gdb.Value(0), level = 0):
self.seen.add(long(ptr))
addr = ptr['addr']
addr += offset
size = int128(ptr['size'])
alias = ptr['alias']
klass = ''
if not isnull(alias):
klass = ' (alias)'
elif not isnull(ptr['ops']):
klass = ' (I/O)'
elif bool(ptr['ram']):
klass = ' (RAM)'
gdb.write('%s%016x-%016x %s%s (@ %s)\n'
% (' ' * level,
long(addr),
long(addr + (size - 1)),
ptr['name'].string(),
klass,
ptr,
),
gdb.STDOUT)
if not isnull(alias):
gdb.write('%s alias: %s@%016x (@ %s)\n' %
(' ' * level,
alias['name'].string(),
ptr['alias_offset'],
alias,
),
gdb.STDOUT)
self.queue.append(alias)
subregion = ptr['subregions']['tqh_first']
level += 1
while not isnull(subregion):
self.print_item(subregion, addr, level)
subregion = subregion['subregions_link']['tqe_next']
QemuCommand()
CoroutineCommand()
MtreeCommand()
|
