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#ifndef BASE_DEBUG_STACK_TRACE_H_ 6#define BASE_DEBUG_STACK_TRACE_H_ 7 8#include <stddef.h> 9 10#include <iosfwd> 11#include <string> 12 13#include "base/base_export.h" 14#include "build/build_config.h" 15 16#if defined(OS_POSIX) 17#include <unistd.h> 18#endif 19 20#if defined(OS_WIN) 21struct _EXCEPTION_POINTERS; 22struct _CONTEXT; 23#endif 24 25namespace base { 26namespace debug { 27 28// Enables stack dump to console output on exception and signals. 29// When enabled, the process will quit immediately. This is meant to be used in 30// unit_tests only! This is not thread-safe: only call from main thread. 31// In sandboxed processes, this has to be called before the sandbox is turned 32// on. 33// Calling this function on Linux opens /proc/self/maps and caches its 34// contents. In non-official builds, this function also opens the object files 35// that are loaded in memory and caches their file descriptors (this cannot be 36// done in official builds because it has security implications). 37BASE_EXPORT bool EnableInProcessStackDumping(); 38 39// A stacktrace can be helpful in debugging. For example, you can include a 40// stacktrace member in a object (probably around #ifndef NDEBUG) so that you 41// can later see where the given object was created from. 42class BASE_EXPORT StackTrace { 43 public: 44 // Creates a stacktrace from the current location. 45 StackTrace(); 46 47 // Creates a stacktrace from an existing array of instruction 48 // pointers (such as returned by Addresses()). |count| will be 49 // trimmed to |kMaxTraces|. 50 StackTrace(const void* const* trace, size_t count); 51 52#if defined(OS_WIN) 53 // Creates a stacktrace for an exception. 54 // Note: this function will throw an import not found (StackWalk64) exception 55 // on system without dbghelp 5.1. 56 StackTrace(_EXCEPTION_POINTERS* exception_pointers); 57 StackTrace(const _CONTEXT* context); 58#endif 59 60 // Copying and assignment are allowed with the default functions. 61 62 ~StackTrace(); 63 64 // Gets an array of instruction pointer values. |*count| will be set to the 65 // number of elements in the returned array. 66 const void* const* Addresses(size_t* count) const; 67 68 // Prints the stack trace to stderr. 69 void Print() const; 70 71#if !defined(__UCLIBC__) 72 // Resolves backtrace to symbols and write to stream. 73 void OutputToStream(std::ostream* os) const; 74#endif 75 76 // Resolves backtrace to symbols and returns as string. 77 std::string ToString() const; 78 79 private: 80#if defined(OS_WIN) 81 void InitTrace(const _CONTEXT* context_record); 82#endif 83 84 // From http://msdn.microsoft.com/en-us/library/bb204633.aspx, 85 // the sum of FramesToSkip and FramesToCapture must be less than 63, 86 // so set it to 62. Even if on POSIX it could be a larger value, it usually 87 // doesn't give much more information. 88 static const int kMaxTraces = 62; 89 90 void* trace_[kMaxTraces]; 91 92 // The number of valid frames in |trace_|. 93 size_t count_; 94}; 95 96namespace internal { 97 98#if defined(OS_POSIX) && !defined(OS_ANDROID) 99// POSIX doesn't define any async-signal safe function for converting 100// an integer to ASCII. We'll have to define our own version. 101// itoa_r() converts a (signed) integer to ASCII. It returns "buf", if the 102// conversion was successful or NULL otherwise. It never writes more than "sz" 103// bytes. Output will be truncated as needed, and a NUL character is always 104// appended. 105BASE_EXPORT char *itoa_r(intptr_t i, 106 char *buf, 107 size_t sz, 108 int base, 109 size_t padding); 110#endif // defined(OS_POSIX) && !defined(OS_ANDROID) 111 112} // namespace internal 113 114} // namespace debug 115} // namespace base 116 117#endif // BASE_DEBUG_STACK_TRACE_H_ 118