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