base/debug/stack_trace.h

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