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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "base/debug/stack_trace.h" | |
6 | |
7 #include <windows.h> | |
8 #include <dbghelp.h> | |
9 | |
10 #include <iostream> | |
11 | |
12 #include "base/basictypes.h" | |
13 #include "base/logging.h" | |
14 #include "base/memory/singleton.h" | |
15 #include "base/process/launch.h" | |
16 #include "base/strings/string_util.h" | |
17 #include "base/synchronization/lock.h" | |
18 #include "base/win/windows_version.h" | |
19 | |
20 namespace base { | |
21 namespace debug { | |
22 | |
23 namespace { | |
24 | |
25 // Previous unhandled filter. Will be called if not NULL when we intercept an | |
26 // exception. Only used in unit tests. | |
27 LPTOP_LEVEL_EXCEPTION_FILTER g_previous_filter = NULL; | |
28 | |
29 // Prints the exception call stack. | |
30 // This is the unit tests exception filter. | |
31 long WINAPI StackDumpExceptionFilter(EXCEPTION_POINTERS* info) { | |
32 debug::StackTrace(info).Print(); | |
33 if (g_previous_filter) | |
34 return g_previous_filter(info); | |
35 return EXCEPTION_CONTINUE_SEARCH; | |
36 } | |
37 | |
38 FilePath GetExePath() { | |
39 wchar_t system_buffer[MAX_PATH]; | |
40 GetModuleFileName(NULL, system_buffer, MAX_PATH); | |
41 system_buffer[MAX_PATH - 1] = L'\0'; | |
42 return FilePath(system_buffer); | |
43 } | |
44 | |
45 // SymbolContext is a threadsafe singleton that wraps the DbgHelp Sym* family | |
46 // of functions. The Sym* family of functions may only be invoked by one | |
47 // thread at a time. SymbolContext code may access a symbol server over the | |
48 // network while holding the lock for this singleton. In the case of high | |
49 // latency, this code will adversely affect performance. | |
50 // | |
51 // There is also a known issue where this backtrace code can interact | |
52 // badly with breakpad if breakpad is invoked in a separate thread while | |
53 // we are using the Sym* functions. This is because breakpad does now | |
54 // share a lock with this function. See this related bug: | |
55 // | |
56 // http://code.google.com/p/google-breakpad/issues/detail?id=311 | |
57 // | |
58 // This is a very unlikely edge case, and the current solution is to | |
59 // just ignore it. | |
60 class SymbolContext { | |
61 public: | |
62 static SymbolContext* GetInstance() { | |
63 // We use a leaky singleton because code may call this during process | |
64 // termination. | |
65 return | |
66 Singleton<SymbolContext, LeakySingletonTraits<SymbolContext> >::get(); | |
67 } | |
68 | |
69 // Returns the error code of a failed initialization. | |
70 DWORD init_error() const { | |
71 return init_error_; | |
72 } | |
73 | |
74 // For the given trace, attempts to resolve the symbols, and output a trace | |
75 // to the ostream os. The format for each line of the backtrace is: | |
76 // | |
77 // <tab>SymbolName[0xAddress+Offset] (FileName:LineNo) | |
78 // | |
79 // This function should only be called if Init() has been called. We do not | |
80 // LOG(FATAL) here because this code is called might be triggered by a | |
81 // LOG(FATAL) itself. Also, it should not be calling complex code that is | |
82 // extensible like PathService since that can in turn fire CHECKs. | |
83 void OutputTraceToStream(const void* const* trace, | |
84 size_t count, | |
85 std::ostream* os) { | |
86 base::AutoLock lock(lock_); | |
87 | |
88 for (size_t i = 0; (i < count) && os->good(); ++i) { | |
89 const int kMaxNameLength = 256; | |
90 DWORD_PTR frame = reinterpret_cast<DWORD_PTR>(trace[i]); | |
91 | |
92 // Code adapted from MSDN example: | |
93 // http://msdn.microsoft.com/en-us/library/ms680578(VS.85).aspx | |
94 ULONG64 buffer[ | |
95 (sizeof(SYMBOL_INFO) + | |
96 kMaxNameLength * sizeof(wchar_t) + | |
97 sizeof(ULONG64) - 1) / | |
98 sizeof(ULONG64)]; | |
99 memset(buffer, 0, sizeof(buffer)); | |
100 | |
101 // Initialize symbol information retrieval structures. | |
102 DWORD64 sym_displacement = 0; | |
103 PSYMBOL_INFO symbol = reinterpret_cast<PSYMBOL_INFO>(&buffer[0]); | |
104 symbol->SizeOfStruct = sizeof(SYMBOL_INFO); | |
105 symbol->MaxNameLen = kMaxNameLength - 1; | |
106 BOOL has_symbol = SymFromAddr(GetCurrentProcess(), frame, | |
107 &sym_displacement, symbol); | |
108 | |
109 // Attempt to retrieve line number information. | |
110 DWORD line_displacement = 0; | |
111 IMAGEHLP_LINE64 line = {}; | |
112 line.SizeOfStruct = sizeof(IMAGEHLP_LINE64); | |
113 BOOL has_line = SymGetLineFromAddr64(GetCurrentProcess(), frame, | |
114 &line_displacement, &line); | |
115 | |
116 // Output the backtrace line. | |
117 (*os) << "\t"; | |
118 if (has_symbol) { | |
119 (*os) << symbol->Name << " [0x" << trace[i] << "+" | |
120 << sym_displacement << "]"; | |
121 } else { | |
122 // If there is no symbol information, add a spacer. | |
123 (*os) << "(No symbol) [0x" << trace[i] << "]"; | |
124 } | |
125 if (has_line) { | |
126 (*os) << " (" << line.FileName << ":" << line.LineNumber << ")"; | |
127 } | |
128 (*os) << "\n"; | |
129 } | |
130 } | |
131 | |
132 private: | |
133 friend struct DefaultSingletonTraits<SymbolContext>; | |
134 | |
135 SymbolContext() : init_error_(ERROR_SUCCESS) { | |
136 // Initializes the symbols for the process. | |
137 // Defer symbol load until they're needed, use undecorated names, and | |
138 // get line numbers. | |
139 SymSetOptions(SYMOPT_DEFERRED_LOADS | | |
140 SYMOPT_UNDNAME | | |
141 SYMOPT_LOAD_LINES); | |
142 if (!SymInitialize(GetCurrentProcess(), NULL, TRUE)) { | |
143 init_error_ = GetLastError(); | |
144 // TODO(awong): Handle error: SymInitialize can fail with | |
145 // ERROR_INVALID_PARAMETER. | |
146 // When it fails, we should not call debugbreak since it kills the current | |
147 // process (prevents future tests from running or kills the browser | |
148 // process). | |
149 DLOG(ERROR) << "SymInitialize failed: " << init_error_; | |
150 return; | |
151 } | |
152 | |
153 init_error_ = ERROR_SUCCESS; | |
154 | |
155 // When transferring the binaries e.g. between bots, path put | |
156 // into the executable will get off. To still retrieve symbols correctly, | |
157 // add the directory of the executable to symbol search path. | |
158 // All following errors are non-fatal. | |
159 const size_t kSymbolsArraySize = 1024; | |
160 scoped_ptr<wchar_t[]> symbols_path(new wchar_t[kSymbolsArraySize]); | |
161 | |
162 // Note: The below function takes buffer size as number of characters, | |
163 // not number of bytes! | |
164 if (!SymGetSearchPathW(GetCurrentProcess(), | |
165 symbols_path.get(), | |
166 kSymbolsArraySize)) { | |
167 DLOG(WARNING) << "SymGetSearchPath failed: "; | |
168 return; | |
169 } | |
170 | |
171 std::wstring new_path(std::wstring(symbols_path.get()) + | |
172 L";" + GetExePath().DirName().value()); | |
173 if (!SymSetSearchPathW(GetCurrentProcess(), new_path.c_str())) { | |
174 DLOG(WARNING) << "SymSetSearchPath failed."; | |
175 return; | |
176 } | |
177 } | |
178 | |
179 DWORD init_error_; | |
180 base::Lock lock_; | |
181 DISALLOW_COPY_AND_ASSIGN(SymbolContext); | |
182 }; | |
183 | |
184 } // namespace | |
185 | |
186 bool EnableInProcessStackDumping() { | |
187 // Add stack dumping support on exception on windows. Similar to OS_POSIX | |
188 // signal() handling in process_util_posix.cc. | |
189 g_previous_filter = SetUnhandledExceptionFilter(&StackDumpExceptionFilter); | |
190 RouteStdioToConsole(); | |
191 return true; | |
192 } | |
193 | |
194 // Disable optimizations for the StackTrace::StackTrace function. It is | |
195 // important to disable at least frame pointer optimization ("y"), since | |
196 // that breaks CaptureStackBackTrace() and prevents StackTrace from working | |
197 // in Release builds (it may still be janky if other frames are using FPO, | |
198 // but at least it will make it further). | |
199 #if defined(COMPILER_MSVC) | |
200 #pragma optimize("", off) | |
201 #endif | |
202 | |
203 StackTrace::StackTrace() { | |
204 // When walking our own stack, use CaptureStackBackTrace(). | |
205 count_ = CaptureStackBackTrace(0, arraysize(trace_), trace_, NULL); | |
206 } | |
207 | |
208 #if defined(COMPILER_MSVC) | |
209 #pragma optimize("", on) | |
210 #endif | |
211 | |
212 StackTrace::StackTrace(const EXCEPTION_POINTERS* exception_pointers) { | |
213 // StackWalk64() may modify context record passed to it, so we will | |
214 // use a copy. | |
215 CONTEXT context_record = *exception_pointers->ContextRecord; | |
216 InitTrace(&context_record); | |
217 } | |
218 | |
219 StackTrace::StackTrace(const CONTEXT* context) { | |
220 // StackWalk64() may modify context record passed to it, so we will | |
221 // use a copy. | |
222 CONTEXT context_record = *context; | |
223 InitTrace(&context_record); | |
224 } | |
225 | |
226 void StackTrace::InitTrace(CONTEXT* context_record) { | |
227 // When walking an exception stack, we need to use StackWalk64(). | |
228 count_ = 0; | |
229 // Initialize stack walking. | |
230 STACKFRAME64 stack_frame; | |
231 memset(&stack_frame, 0, sizeof(stack_frame)); | |
232 #if defined(_WIN64) | |
233 int machine_type = IMAGE_FILE_MACHINE_AMD64; | |
234 stack_frame.AddrPC.Offset = context_record->Rip; | |
235 stack_frame.AddrFrame.Offset = context_record->Rbp; | |
236 stack_frame.AddrStack.Offset = context_record->Rsp; | |
237 #else | |
238 int machine_type = IMAGE_FILE_MACHINE_I386; | |
239 stack_frame.AddrPC.Offset = context_record->Eip; | |
240 stack_frame.AddrFrame.Offset = context_record->Ebp; | |
241 stack_frame.AddrStack.Offset = context_record->Esp; | |
242 #endif | |
243 stack_frame.AddrPC.Mode = AddrModeFlat; | |
244 stack_frame.AddrFrame.Mode = AddrModeFlat; | |
245 stack_frame.AddrStack.Mode = AddrModeFlat; | |
246 while (StackWalk64(machine_type, | |
247 GetCurrentProcess(), | |
248 GetCurrentThread(), | |
249 &stack_frame, | |
250 context_record, | |
251 NULL, | |
252 &SymFunctionTableAccess64, | |
253 &SymGetModuleBase64, | |
254 NULL) && | |
255 count_ < arraysize(trace_)) { | |
256 trace_[count_++] = reinterpret_cast<void*>(stack_frame.AddrPC.Offset); | |
257 } | |
258 | |
259 for (size_t i = count_; i < arraysize(trace_); ++i) | |
260 trace_[i] = NULL; | |
261 } | |
262 | |
263 void StackTrace::Print() const { | |
264 OutputToStream(&std::cerr); | |
265 } | |
266 | |
267 void StackTrace::OutputToStream(std::ostream* os) const { | |
268 SymbolContext* context = SymbolContext::GetInstance(); | |
269 DWORD error = context->init_error(); | |
270 if (error != ERROR_SUCCESS) { | |
271 (*os) << "Error initializing symbols (" << error | |
272 << "). Dumping unresolved backtrace:\n"; | |
273 for (size_t i = 0; (i < count_) && os->good(); ++i) { | |
274 (*os) << "\t" << trace_[i] << "\n"; | |
275 } | |
276 } else { | |
277 (*os) << "Backtrace:\n"; | |
278 context->OutputTraceToStream(trace_, count_, os); | |
279 } | |
280 } | |
281 | |
282 } // namespace debug | |
283 } // namespace base | |
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