// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef BASE_DEBUG_STACK_TRACE_H_
#define BASE_DEBUG_STACK_TRACE_H_
#include <iosfwd>
#include <string>
#include "base/base_export.h"
#include "build/build_config.h"
#if defined(OS_POSIX)
#include <unistd.h>
#endif
#if defined(OS_WIN)
struct _EXCEPTION_POINTERS;
#endif
namespace base {
namespace debug {
// Enables stack dump to console output on exception and signals.
// When enabled, the process will quit immediately. This is meant to be used in
// unit_tests only! This is not thread-safe: only call from main thread.
BASE_EXPORT bool EnableInProcessStackDumping();
// A different version of EnableInProcessStackDumping that also works for
// sandboxed processes. For more details take a look at the description
// of EnableInProcessStackDumping.
// Calling this function on Linux opens /proc/self/maps and caches its
// contents. In DEBUG builds, this function also opens the object files that
// are loaded in memory and caches their file descriptors (this cannot be
// done in official builds because it has security implications).
BASE_EXPORT bool EnableInProcessStackDumpingForSandbox();
// A stacktrace can be helpful in debugging. For example, you can include a
// stacktrace member in a object (probably around #ifndef NDEBUG) so that you
// can later see where the given object was created from.
class BASE_EXPORT StackTrace {
public:
// Creates a stacktrace from the current location.
StackTrace();
// Creates a stacktrace from an existing array of instruction
// pointers (such as returned by Addresses()). |count| will be
// trimmed to |kMaxTraces|.
StackTrace(const void* const* trace, size_t count);
#if defined(OS_WIN)
// Creates a stacktrace for an exception.
// Note: this function will throw an import not found (StackWalk64) exception
// on system without dbghelp 5.1.
StackTrace(_EXCEPTION_POINTERS* exception_pointers);
#endif
// Copying and assignment are allowed with the default functions.
~StackTrace();
// Gets an array of instruction pointer values. |*count| will be set to the
// number of elements in the returned array.
const void* const* Addresses(size_t* count) const;
// Prints the stack trace to stderr.
void Print() const;
// Resolves backtrace to symbols and write to stream.
void OutputToStream(std::ostream* os) const;
// Resolves backtrace to symbols and returns as string.
std::string ToString() const;
private:
// From http://msdn.microsoft.com/en-us/library/bb204633.aspx,
// the sum of FramesToSkip and FramesToCapture must be less than 63,
// so set it to 62. Even if on POSIX it could be a larger value, it usually
// doesn't give much more information.
static const int kMaxTraces = 62;
void* trace_[kMaxTraces];
// The number of valid frames in |trace_|.
size_t count_;
};
namespace internal {
#if defined(OS_POSIX) && !defined(OS_ANDROID)
// POSIX doesn't define any async-signal safe function for converting
// an integer to ASCII. We'll have to define our own version.
// itoa_r() converts a (signed) integer to ASCII. It returns "buf", if the
// conversion was successful or NULL otherwise. It never writes more than "sz"
// bytes. Output will be truncated as needed, and a NUL character is always
// appended.
BASE_EXPORT char *itoa_r(intptr_t i,
char *buf,
size_t sz,
int base,
size_t padding);
#endif // defined(OS_POSIX) && !defined(OS_ANDROID)
} // namespace internal
} // namespace debug
} // namespace base
#endif // BASE_DEBUG_STACK_TRACE_H_