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 #endif
  21
  22 namespace base {
  23 namespace debug {
  24
  25 // Enables stack dump to console output on exception and signals.
  26 // When enabled, the process will quit immediately. This is meant to be used in
  27 // unit_tests only! This is not thread-safe: only call from main thread.
  28 BASE_EXPORT bool EnableInProcessStackDumping();
  29
  30 // A different version of EnableInProcessStackDumping that also works for
  31 // sandboxed processes.  For more details take a look at the description
  32 // of EnableInProcessStackDumping.
  33 // Calling this function on Linux opens /proc/self/maps and caches its
  34 // contents. In DEBUG builds, this function also opens the object files that
  35 // are loaded in memory and caches their file descriptors (this cannot be
  36 // done in official builds because it has security implications).
  37 BASE_EXPORT bool EnableInProcessStackDumpingForSandbox();
  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.
  42 class 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 #endif
  58
  59   // Copying and assignment are allowed with the default functions.
  60
  61   ~StackTrace();
  62
  63   // Gets an array of instruction pointer values. |*count| will be set to the
  64   // number of elements in the returned array.
  65   const void* const* Addresses(size_t* count) const;
  66
  67   // Prints the stack trace to stderr.
  68   void Print() const;
  69
  70   // Resolves backtrace to symbols and write to stream.
  71   void OutputToStream(std::ostream* os) const;
  72
  73   // Resolves backtrace to symbols and returns as string.
  74   std::string ToString() const;
  75
  76  private:
  77   // From http://msdn.microsoft.com/en-us/library/bb204633.aspx,
  78   // the sum of FramesToSkip and FramesToCapture must be less than 63,
  79   // so set it to 62. Even if on POSIX it could be a larger value, it usually
  80   // doesn't give much more information.
  81   static const int kMaxTraces = 62;
  82
  83   void* trace_[kMaxTraces];
  84
  85   // The number of valid frames in |trace_|.
  86   size_t count_;
  87 };
  88
  89 namespace internal {
  90
  91 #if defined(OS_POSIX) && !defined(OS_ANDROID)
  92 // POSIX doesn't define any async-signal safe function for converting
  93 // an integer to ASCII. We'll have to define our own version.
  94 // itoa_r() converts a (signed) integer to ASCII. It returns "buf", if the
  95 // conversion was successful or NULL otherwise. It never writes more than "sz"
  96 // bytes. Output will be truncated as needed, and a NUL character is always
  97 // appended.
  98 BASE_EXPORT char *itoa_r(intptr_t i,
  99                          char *buf,
 100                          size_t sz,
 101                          int base,
 102                          size_t padding);
 103 #endif  // defined(OS_POSIX) && !defined(OS_ANDROID)
 104
 105 }  // namespace internal
 106
 107 }  // namespace debug
 108 }  // namespace base
 109
 110 #endif  // BASE_DEBUG_STACK_TRACE_H_