1 // Copyright (c) 2011 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 <errno.h>
8 #include <execinfo.h>
9 #include <fcntl.h>
10 #include <stdio.h>
11 #include <stdlib.h>
12 #include <sys/param.h>
13 #include <sys/stat.h>
14 #include <sys/sysctl.h>
15 #include <sys/types.h>
16 #include <unistd.h>
17
18 #include <string>
19 #include <vector>
20
21 #if defined(__GLIBCXX__)
22 #include <cxxabi.h>
23 #endif
24
25 #if defined(OS_MACOSX)
26 #include <AvailabilityMacros.h>
27 #endif
28
29 #include <iostream>
30
31 #include "base/basictypes.h"
32 #include "base/eintr_wrapper.h"
33 #include "base/logging.h"
34 #include "base/memory/scoped_ptr.h"
35 #include "base/safe_strerror_posix.h"
36 #include "base/string_piece.h"
37 #include "base/stringprintf.h"
38
39 #if defined(USE_SYMBOLIZE)
40 #include "base/third_party/symbolize/symbolize.h"
41 #endif
42
43 namespace base {
44 namespace debug {
45
46 namespace {
47
48 // The prefix used for mangled symbols, per the Itanium C++ ABI:
49 // http://www.codesourcery.com/cxx-abi/abi.html#mangling
50 const char kMangledSymbolPrefix[] = "_Z";
51
52 // Characters that can be used for symbols, generated by Ruby:
53 // (('a'..'z').to_a+('A'..'Z').to_a+('0'..'9').to_a + ['_']).join
54 const char kSymbolCharacters[] =
55 "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
56
57 #if !defined(USE_SYMBOLIZE)
58 // Demangles C++ symbols in the given text. Example:
59 //
60 // "out/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"
61 // =>
62 // "out/Debug/base_unittests(StackTrace::StackTrace()+0x20) [0x817778c]"
DemangleSymbols(std::string * text)63 void DemangleSymbols(std::string* text) {
64 #if defined(__GLIBCXX__)
65
66 std::string::size_type search_from = 0;
67 while (search_from < text->size()) {
68 // Look for the start of a mangled symbol, from search_from.
69 std::string::size_type mangled_start =
70 text->find(kMangledSymbolPrefix, search_from);
71 if (mangled_start == std::string::npos) {
72 break; // Mangled symbol not found.
73 }
74
75 // Look for the end of the mangled symbol.
76 std::string::size_type mangled_end =
77 text->find_first_not_of(kSymbolCharacters, mangled_start);
78 if (mangled_end == std::string::npos) {
79 mangled_end = text->size();
80 }
81 std::string mangled_symbol =
82 text->substr(mangled_start, mangled_end - mangled_start);
83
84 // Try to demangle the mangled symbol candidate.
85 int status = 0;
86 scoped_ptr_malloc<char> demangled_symbol(
87 abi::__cxa_demangle(mangled_symbol.c_str(), NULL, 0, &status));
88 if (status == 0) { // Demangling is successful.
89 // Remove the mangled symbol.
90 text->erase(mangled_start, mangled_end - mangled_start);
91 // Insert the demangled symbol.
92 text->insert(mangled_start, demangled_symbol.get());
93 // Next time, we'll start right after the demangled symbol we inserted.
94 search_from = mangled_start + strlen(demangled_symbol.get());
95 } else {
96 // Failed to demangle. Retry after the "_Z" we just found.
97 search_from = mangled_start + 2;
98 }
99 }
100
101 #endif // defined(__GLIBCXX__)
102 }
103 #endif // !defined(USE_SYMBOLIZE)
104
105 // Gets the backtrace as a vector of strings. If possible, resolve symbol
106 // names and attach these. Otherwise just use raw addresses. Returns true
107 // if any symbol name is resolved. Returns false on error and *may* fill
108 // in |error_message| if an error message is available.
GetBacktraceStrings(void * const * trace,int size,std::vector<std::string> * trace_strings,std::string * error_message)109 bool GetBacktraceStrings(void *const *trace, int size,
110 std::vector<std::string>* trace_strings,
111 std::string* error_message) {
112 #ifdef ANDROID
113 return false;
114 #endif
115 bool symbolized = false;
116
117 #if defined(USE_SYMBOLIZE)
118 for (int i = 0; i < size; ++i) {
119 char symbol[1024];
120 // Subtract by one as return address of function may be in the next
121 // function when a function is annotated as noreturn.
122 if (google::Symbolize(static_cast<char *>(trace[i]) - 1,
123 symbol, sizeof(symbol))) {
124 // Don't call DemangleSymbols() here as the symbol is demangled by
125 // google::Symbolize().
126 trace_strings->push_back(
127 base::StringPrintf("%s [%p]", symbol, trace[i]));
128 symbolized = true;
129 } else {
130 trace_strings->push_back(base::StringPrintf("%p", trace[i]));
131 }
132 }
133 #else
134 scoped_ptr_malloc<char*> trace_symbols(backtrace_symbols(trace, size));
135 if (trace_symbols.get()) {
136 for (int i = 0; i < size; ++i) {
137 std::string trace_symbol = trace_symbols.get()[i];
138 DemangleSymbols(&trace_symbol);
139 trace_strings->push_back(trace_symbol);
140 }
141 symbolized = true;
142 } else {
143 if (error_message)
144 *error_message = safe_strerror(errno);
145 for (int i = 0; i < size; ++i) {
146 trace_strings->push_back(base::StringPrintf("%p", trace[i]));
147 }
148 }
149 #endif // defined(USE_SYMBOLIZE)
150
151 return symbolized;
152 }
153
154 } // namespace
155
StackTrace()156 StackTrace::StackTrace() {
157 #if (defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5) || defined(ANDROID)
158 #if defined(ANDROID)
159 return;
160 #else
161 if (backtrace == NULL) {
162 count_ = 0;
163 return;
164 }
165 #endif // ANDROID
166 #endif
167 // Though the backtrace API man page does not list any possible negative
168 // return values, we take no chance.
169 count_ = std::max(backtrace(trace_, arraysize(trace_)), 0);
170 }
171
PrintBacktrace() const172 void StackTrace::PrintBacktrace() const {
173 #if (defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5) || defined(ANDROID)
174 #if defined(ANDROID)
175 return;
176 #else
177 if (backtrace_symbols_fd == NULL)
178 return;
179 #endif // ANDROID
180 #endif
181 fflush(stderr);
182 std::vector<std::string> trace_strings;
183 GetBacktraceStrings(trace_, count_, &trace_strings, NULL);
184 for (size_t i = 0; i < trace_strings.size(); ++i) {
185 std::cerr << "\t" << trace_strings[i] << "\n";
186 }
187 }
188
OutputToStream(std::ostream * os) const189 void StackTrace::OutputToStream(std::ostream* os) const {
190 #if (defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5) || defined(ANDROID)
191 #if defined(ANDROID)
192 return;
193 #else
194 if (backtrace_symbols == NULL)
195 return;
196 #endif // ANDROID
197 #endif
198 std::vector<std::string> trace_strings;
199 std::string error_message;
200 if (GetBacktraceStrings(trace_, count_, &trace_strings, &error_message)) {
201 (*os) << "Backtrace:\n";
202 } else {
203 if (!error_message.empty())
204 error_message = " (" + error_message + ")";
205 (*os) << "Unable to get symbols for backtrace" << error_message << ". "
206 << "Dumping raw addresses in trace:\n";
207 }
208
209 for (size_t i = 0; i < trace_strings.size(); ++i) {
210 (*os) << "\t" << trace_strings[i] << "\n";
211 }
212 }
213
214 } // namespace debug
215 } // namespace base
216