stack_trace_posix.cc revision 513209b27ff55e2841eac0e4120199c23acce758 
1// Copyright (c) 2010 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 <fcntl.h>
9#include <stdio.h>
10#include <stdlib.h>
11#include <sys/stat.h>
12#include <sys/sysctl.h>
13#include <sys/types.h>
14#include <unistd.h>
15
16#include <string>
17#include <vector>
18
19#if defined(__GLIBCXX__)
20#include <cxxabi.h>
21#endif
22
23#if defined(OS_MACOSX)
24#include <AvailabilityMacros.h>
25#endif
26
27#include <iostream>
28
29#include "base/basictypes.h"
30#include "base/compat_execinfo.h"
31#include "base/eintr_wrapper.h"
32#include "base/logging.h"
33#include "base/safe_strerror_posix.h"
34#include "base/scoped_ptr.h"
35#include "base/string_piece.h"
36#include "base/stringprintf.h"
37
38#if defined(USE_SYMBOLIZE)
39#include "base/third_party/symbolize/symbolize.h"
40#endif
41
42namespace base {
43namespace debug {
44
45namespace {
46
47// The prefix used for mangled symbols, per the Itanium C++ ABI:
48// http://www.codesourcery.com/cxx-abi/abi.html#mangling
49const char kMangledSymbolPrefix[] = "_Z";
50
51// Characters that can be used for symbols, generated by Ruby:
52// (('a'..'z').to_a+('A'..'Z').to_a+('0'..'9').to_a + ['_']).join
53const char kSymbolCharacters[] =
54    "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_";
55
56#if !defined(USE_SYMBOLIZE)
57// Demangles C++ symbols in the given text. Example:
58//
59// "sconsbuild/Debug/base_unittests(_ZN10StackTraceC1Ev+0x20) [0x817778c]"
60// =>
61// "sconsbuild/Debug/base_unittests(StackTrace::StackTrace()+0x20) [0x817778c]"
62void DemangleSymbols(std::string* text) {
63#if defined(__GLIBCXX__)
64
65  std::string::size_type search_from = 0;
66  while (search_from < text->size()) {
67    // Look for the start of a mangled symbol, from search_from.
68    std::string::size_type mangled_start =
69        text->find(kMangledSymbolPrefix, search_from);
70    if (mangled_start == std::string::npos) {
71      break;  // Mangled symbol not found.
72    }
73
74    // Look for the end of the mangled symbol.
75    std::string::size_type mangled_end =
76        text->find_first_not_of(kSymbolCharacters, mangled_start);
77    if (mangled_end == std::string::npos) {
78      mangled_end = text->size();
79    }
80    std::string mangled_symbol =
81        text->substr(mangled_start, mangled_end - mangled_start);
82
83    // Try to demangle the mangled symbol candidate.
84    int status = 0;
85    scoped_ptr_malloc<char> demangled_symbol(
86        abi::__cxa_demangle(mangled_symbol.c_str(), NULL, 0, &status));
87    if (status == 0) {  // Demangling is successful.
88      // Remove the mangled symbol.
89      text->erase(mangled_start, mangled_end - mangled_start);
90      // Insert the demangled symbol.
91      text->insert(mangled_start, demangled_symbol.get());
92      // Next time, we'll start right after the demangled symbol we inserted.
93      search_from = mangled_start + strlen(demangled_symbol.get());
94    } else {
95      // Failed to demangle.  Retry after the "_Z" we just found.
96      search_from = mangled_start + 2;
97    }
98  }
99
100#endif  // defined(__GLIBCXX__)
101}
102#endif  // !defined(USE_SYMBOLIZE)
103
104// Gets the backtrace as a vector of strings. If possible, resolve symbol
105// names and attach these. Otherwise just use raw addresses. Returns true
106// if any symbol name is resolved.  Returns false on error and *may* fill
107// in |error_message| if an error message is available.
108bool GetBacktraceStrings(void **trace, int size,
109                         std::vector<std::string>* trace_strings,
110                         std::string* error_message) {
111  bool symbolized = false;
112
113#if defined(USE_SYMBOLIZE)
114  for (int i = 0; i < size; ++i) {
115    char symbol[1024];
116    // Subtract by one as return address of function may be in the next
117    // function when a function is annotated as noreturn.
118    if (google::Symbolize(static_cast<char *>(trace[i]) - 1,
119                          symbol, sizeof(symbol))) {
120      // Don't call DemangleSymbols() here as the symbol is demangled by
121      // google::Symbolize().
122      trace_strings->push_back(
123          base::StringPrintf("%s [%p]", symbol, trace[i]));
124      symbolized = true;
125    } else {
126      trace_strings->push_back(base::StringPrintf("%p", trace[i]));
127    }
128  }
129#else
130  scoped_ptr_malloc<char*> trace_symbols(backtrace_symbols(trace, size));
131  if (trace_symbols.get()) {
132    for (int i = 0; i < size; ++i) {
133      std::string trace_symbol = trace_symbols.get()[i];
134      DemangleSymbols(&trace_symbol);
135      trace_strings->push_back(trace_symbol);
136    }
137    symbolized = true;
138  } else {
139    if (error_message)
140      *error_message = safe_strerror(errno);
141    for (int i = 0; i < size; ++i) {
142      trace_strings->push_back(base::StringPrintf("%p", trace[i]));
143    }
144  }
145#endif  // defined(USE_SYMBOLIZE)
146
147  return symbolized;
148}
149
150}  // namespace
151
152StackTrace::StackTrace() {
153#if defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
154  if (backtrace == NULL) {
155    count_ = 0;
156    return;
157  }
158#endif
159  // Though the backtrace API man page does not list any possible negative
160  // return values, we take no chance.
161  count_ = std::max(backtrace(trace_, arraysize(trace_)), 0);
162}
163
164void StackTrace::PrintBacktrace() {
165#if defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
166  if (backtrace_symbols_fd == NULL)
167    return;
168#endif
169  fflush(stderr);
170  std::vector<std::string> trace_strings;
171  GetBacktraceStrings(trace_, count_, &trace_strings, NULL);
172  for (size_t i = 0; i < trace_strings.size(); ++i) {
173    std::cerr << "\t" << trace_strings[i] << "\n";
174  }
175}
176
177void StackTrace::OutputToStream(std::ostream* os) {
178#if defined(OS_MACOSX) && MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_5
179  if (backtrace_symbols == NULL)
180    return;
181#endif
182  std::vector<std::string> trace_strings;
183  std::string error_message;
184  if (GetBacktraceStrings(trace_, count_, &trace_strings, &error_message)) {
185    (*os) << "Backtrace:\n";
186  } else {
187    if (!error_message.empty())
188      error_message = " (" + error_message + ")";
189    (*os) << "Unable to get symbols for backtrace" << error_message << ". "
190          << "Dumping raw addresses in trace:\n";
191  }
192
193  for (size_t i = 0; i < trace_strings.size(); ++i) {
194    (*os) << "\t" << trace_strings[i] << "\n";
195  }
196}
197
198}  // namespace debug
199}  // namespace base
200