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
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
|
/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdint.h>
#include <sys/types.h>
#include <ucontext.h>
#include <libunwind.h>
#include <libunwind-ptrace.h>
#include <backtrace/Backtrace.h>
#include <backtrace/BacktraceMap.h>
#include "BacktraceLog.h"
#include "UnwindMap.h"
#include "UnwindPtrace.h"
UnwindPtrace::UnwindPtrace(pid_t pid, pid_t tid, BacktraceMap* map)
: BacktracePtrace(pid, tid, map), addr_space_(nullptr), upt_info_(nullptr) {
}
UnwindPtrace::~UnwindPtrace() {
if (upt_info_) {
_UPT_destroy(upt_info_);
upt_info_ = nullptr;
}
if (addr_space_) {
// Remove the map from the address space before destroying it.
// It will be freed in the UnwindMap destructor.
unw_map_set(addr_space_, nullptr);
unw_destroy_addr_space(addr_space_);
addr_space_ = nullptr;
}
}
bool UnwindPtrace::Init() {
if (upt_info_) {
return true;
}
if (addr_space_) {
// If somehow the addr_space_ gets initialized but upt_info_ doesn't,
// then that indicates there is some kind of failure.
return false;
}
addr_space_ = unw_create_addr_space(&_UPT_accessors, 0);
if (!addr_space_) {
BACK_LOGW("unw_create_addr_space failed.");
error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
return false;
}
UnwindMap* map = static_cast<UnwindMap*>(GetMap());
unw_map_set(addr_space_, map->GetMapCursor());
upt_info_ = reinterpret_cast<struct UPT_info*>(_UPT_create(Tid()));
if (!upt_info_) {
BACK_LOGW("Failed to create upt info.");
error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
return false;
}
return true;
}
bool UnwindPtrace::Unwind(size_t num_ignore_frames, ucontext_t* ucontext) {
if (GetMap() == nullptr) {
// Without a map object, we can't do anything.
error_ = BACKTRACE_UNWIND_ERROR_MAP_MISSING;
return false;
}
error_ = BACKTRACE_UNWIND_NO_ERROR;
if (ucontext) {
BACK_LOGW("Unwinding from a specified context not supported yet.");
error_ = BACKTRACE_UNWIND_ERROR_UNSUPPORTED_OPERATION;
return false;
}
if (!Init()) {
return false;
}
unw_cursor_t cursor;
int ret = unw_init_remote(&cursor, addr_space_, upt_info_);
if (ret < 0) {
BACK_LOGW("unw_init_remote failed %d", ret);
error_ = BACKTRACE_UNWIND_ERROR_SETUP_FAILED;
return false;
}
size_t num_frames = 0;
do {
unw_word_t pc;
ret = unw_get_reg(&cursor, UNW_REG_IP, &pc);
if (ret < 0) {
BACK_LOGW("Failed to read IP %d", ret);
break;
}
unw_word_t sp;
ret = unw_get_reg(&cursor, UNW_REG_SP, &sp);
if (ret < 0) {
BACK_LOGW("Failed to read SP %d", ret);
break;
}
if (num_ignore_frames == 0) {
frames_.resize(num_frames+1);
backtrace_frame_data_t* frame = &frames_.at(num_frames);
frame->num = num_frames;
frame->pc = static_cast<uintptr_t>(pc);
frame->sp = static_cast<uintptr_t>(sp);
frame->stack_size = 0;
if (num_frames > 0) {
backtrace_frame_data_t* prev = &frames_.at(num_frames-1);
prev->stack_size = frame->sp - prev->sp;
}
FillInMap(frame->pc, &frame->map);
if (BacktraceMap::IsValid(frame->map)) {
frame->rel_pc = frame->pc - frame->map.start + frame->map.load_bias;
} else {
frame->rel_pc = frame->pc;
}
frame->func_name = GetFunctionName(frame->pc, &frame->func_offset, &frame->map);
num_frames++;
// If the pc is in a device map, then don't try to step.
if (frame->map.flags & PROT_DEVICE_MAP) {
break;
}
} else {
// If the pc is in a device map, then don't try to step.
backtrace_map_t map;
FillInMap(pc, &map);
if (map.flags & PROT_DEVICE_MAP) {
break;
}
num_ignore_frames--;
}
// Verify the sp is not in a device map.
backtrace_map_t map;
FillInMap(sp, &map);
if (map.flags & PROT_DEVICE_MAP) {
break;
}
ret = unw_step (&cursor);
} while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
return true;
}
std::string UnwindPtrace::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
if (!Init()) {
return "";
}
*offset = 0;
char buf[512];
unw_word_t value;
if (unw_get_proc_name_by_ip(addr_space_, pc, buf, sizeof(buf), &value,
upt_info_) >= 0 && buf[0] != '\0') {
*offset = static_cast<uintptr_t>(value);
return buf;
}
return "";
}
|
