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
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
// Copyright (c) 2006-2009 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "build/build_config.h"
#include "base/debug_util.h"
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <sys/stat.h>
#include <sys/sysctl.h>
#include <sys/types.h>
#include <unistd.h>
#if defined(__GLIBCXX__)
#include <cxxabi.h>
#endif
#include <string>
#if defined(OS_MACOSX)
#include <AvailabilityMacros.h>
#endif
#include "base/basictypes.h"
#include "base/compat_execinfo.h"
#include "base/eintr_wrapper.h"
#include "base/logging.h"
#include "base/safe_strerror_posix.h"
#include "base/scoped_ptr.h"
#include "base/string_piece.h"
namespace {
// The prefix used for mangled symbols, per the Itanium C++ ABI:
// http://www.codesourcery.com/cxx-abi/abi.html#mangling
const char kMangledSymbolPrefix[] = "_Z";
// Characters that can be used for symbols, generated by Ruby:
// (('a'..'z').to_a+('A'..'Z').to_a+('0'..'9').to_a + ['_']).join
const char kSymbolCharacters[] =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
// Demangles C++ symbols in the given text. Example:
//
// "sconsbuild/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"
// =>
// "sconsbuild/Debug/base_unittests(StackTrace::StackTrace()+0x20) [0x817778c]"
void DemangleSymbols(std::string* text) {
#if defined(__GLIBCXX__)
std::string::size_type search_from = 0;
while (search_from < text->size()) {
// Look for the start of a mangled symbol, from search_from.
std::string::size_type mangled_start =
text->find(kMangledSymbolPrefix, search_from);
if (mangled_start == std::string::npos) {
break; // Mangled symbol not found.
}
// Look for the end of the mangled symbol.
std::string::size_type mangled_end =
text->find_first_not_of(kSymbolCharacters, mangled_start);
if (mangled_end == std::string::npos) {
mangled_end = text->size();
}
std::string mangled_symbol =
text->substr(mangled_start, mangled_end - mangled_start);
// Try to demangle the mangled symbol candidate.
int status = 0;
scoped_ptr_malloc<char> demangled_symbol(
abi::__cxa_demangle(mangled_symbol.c_str(), NULL, 0, &status));
if (status == 0) { // Demangling is successful.
// Remove the mangled symbol.
text->erase(mangled_start, mangled_end - mangled_start);
// Insert the demangled symbol.
text->insert(mangled_start, demangled_symbol.get());
// Next time, we'll start right after the demangled symbol we inserted.
search_from = mangled_start + strlen(demangled_symbol.get());
} else {
// Failed to demangle. Retry after the "_Z" we just found.
search_from = mangled_start + 2;
}
}
#endif // defined(__GLIBCXX__)
}
} // namespace
// static
bool DebugUtil::SpawnDebuggerOnProcess(unsigned /* process_id */) {
NOTIMPLEMENTED();
return false;
}
#if defined(OS_MACOSX)
// Based on Apple's recommended method as described in
// http://developer.apple.com/qa/qa2004/qa1361.html
// static
bool DebugUtil::BeingDebugged() {
// If the process is sandboxed then we can't use the sysctl, so cache the
// value.
static bool is_set = false;
static bool being_debugged = false;
if (is_set) {
return being_debugged;
}
// Initialize mib, which tells sysctl what info we want. In this case,
// we're looking for information about a specific process ID.
int mib[] = {
CTL_KERN,
KERN_PROC,
KERN_PROC_PID,
getpid()
};
// Caution: struct kinfo_proc is marked __APPLE_API_UNSTABLE. The source and
// binary interfaces may change.
struct kinfo_proc info;
size_t info_size = sizeof(info);
int sysctl_result = sysctl(mib, arraysize(mib), &info, &info_size, NULL, 0);
DCHECK(sysctl_result == 0);
if (sysctl_result != 0) {
is_set = true;
being_debugged = false;
return being_debugged;
}
// This process is being debugged if the P_TRACED flag is set.
is_set = true;
being_debugged = (info.kp_proc.p_flag & P_TRACED) != 0;
return being_debugged;
}
#elif defined(OS_LINUX)
// We can look in /proc/self/status for TracerPid. We are likely used in crash
// handling, so we are careful not to use the heap or have side effects.
// Another option that is common is to try to ptrace yourself, but then we
// can't detach without forking(), and that's not so great.
// static
bool DebugUtil::BeingDebugged() {
int status_fd = open("/proc/self/status", O_RDONLY);
if (status_fd == -1)
return false;
// We assume our line will be in the first 1024 characters and that we can
// read this much all at once. In practice this will generally be true.
// This simplifies and speeds up things considerably.
char buf[1024];
ssize_t num_read = HANDLE_EINTR(read(status_fd, buf, sizeof(buf)));
HANDLE_EINTR(close(status_fd));
if (num_read <= 0)
return false;
base::StringPiece status(buf, num_read);
base::StringPiece tracer("TracerPid:\t");
base::StringPiece::size_type pid_index = status.find(tracer);
if (pid_index == base::StringPiece::npos)
return false;
// Our pid is 0 without a debugger, assume this for any pid starting with 0.
pid_index += tracer.size();
return pid_index < status.size() && status[pid_index] != '0';
}
#elif defined(OS_FREEBSD)
bool DebugUtil::BeingDebugged() {
// TODO(benl): can we determine this under FreeBSD?
NOTIMPLEMENTED();
return false;
}
#endif
// static
void DebugUtil::BreakDebugger() {
#if defined(ARCH_CPU_ARM_FAMILY)
asm("bkpt 0");
#else
asm("int3");
#endif
}
StackTrace::StackTrace() {
#if defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
if (backtrace == NULL) {
count_ = 0;
return;
}
#endif
// Though the backtrace API man page does not list any possible negative
// return values, we take no chance.
count_ = std::max(backtrace(trace_, arraysize(trace_)), 0);
}
void StackTrace::PrintBacktrace() {
#if defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
if (backtrace_symbols_fd == NULL)
return;
#endif
fflush(stderr);
backtrace_symbols_fd(trace_, count_, STDERR_FILENO);
}
void StackTrace::OutputToStream(std::ostream* os) {
#if defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
if (backtrace_symbols == NULL)
return;
#endif
scoped_ptr_malloc<char*> trace_symbols(backtrace_symbols(trace_, count_));
// If we can't retrieve the symbols, print an error and just dump the raw
// addresses.
if (trace_symbols.get() == NULL) {
(*os) << "Unable get symbols for backtrace (" << safe_strerror(errno)
<< "). Dumping raw addresses in trace:\n";
for (int i = 0; i < count_; ++i) {
(*os) << "\t" << trace_[i] << "\n";
}
} else {
(*os) << "Backtrace:\n";
for (int i = 0; i < count_; ++i) {
std::string trace_symbol(trace_symbols.get()[i]);
DemangleSymbols(&trace_symbol);
(*os) << "\t" << trace_symbol << "\n";
}
}
}
|
