// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/debug/stack_trace.h"

#include <windows.h>

#include <dbghelp.h>
#include <stddef.h>

#include <algorithm>
#include <iostream>
#include <iterator>
#include <memory>

#include "base/compiler_specific.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/memory/singleton.h"
#include "base/strings/strcat_win.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/synchronization/lock.h"
#include "base/win/delayload_helpers.h"
#include "build/build_config.h"

namespace base::debug {

namespace {

// Previous unhandled filter. Will be called if not NULL when we intercept an
// exception. Only used in unit tests.
LPTOP_LEVEL_EXCEPTION_FILTER g_previous_filter = NULL;

bool g_initialized_symbols = false;
DWORD g_init_error = ERROR_SUCCESS;
// STATUS_INFO_LENGTH_MISMATCH is declared in <ntstatus.h>, but including that
// header creates a conflict with base/win/windows_types.h, so re-declaring it
// here.
DWORD g_status_info_length_mismatch = 0xC0000004;

// Disable to force use of the non-symbolizing path when dbghelp is available.
bool g_should_use_dbghelp = true;

// Prints the exception call stack.
// This is the unit tests exception filter.
long WINAPI StackDumpExceptionFilter(EXCEPTION_POINTERS* info) {
  DWORD exc_code = info->ExceptionRecord->ExceptionCode;
  std::cerr << "Received fatal exception ";
  switch (exc_code) {
    case EXCEPTION_ACCESS_VIOLATION:
      std::cerr << "EXCEPTION_ACCESS_VIOLATION";
      break;
    case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
      std::cerr << "EXCEPTION_ARRAY_BOUNDS_EXCEEDED";
      break;
    case EXCEPTION_BREAKPOINT:
      std::cerr << "EXCEPTION_BREAKPOINT";
      break;
    case EXCEPTION_DATATYPE_MISALIGNMENT:
      std::cerr << "EXCEPTION_DATATYPE_MISALIGNMENT";
      break;
    case EXCEPTION_FLT_DENORMAL_OPERAND:
      std::cerr << "EXCEPTION_FLT_DENORMAL_OPERAND";
      break;
    case EXCEPTION_FLT_DIVIDE_BY_ZERO:
      std::cerr << "EXCEPTION_FLT_DIVIDE_BY_ZERO";
      break;
    case EXCEPTION_FLT_INEXACT_RESULT:
      std::cerr << "EXCEPTION_FLT_INEXACT_RESULT";
      break;
    case EXCEPTION_FLT_INVALID_OPERATION:
      std::cerr << "EXCEPTION_FLT_INVALID_OPERATION";
      break;
    case EXCEPTION_FLT_OVERFLOW:
      std::cerr << "EXCEPTION_FLT_OVERFLOW";
      break;
    case EXCEPTION_FLT_STACK_CHECK:
      std::cerr << "EXCEPTION_FLT_STACK_CHECK";
      break;
    case EXCEPTION_FLT_UNDERFLOW:
      std::cerr << "EXCEPTION_FLT_UNDERFLOW";
      break;
    case EXCEPTION_ILLEGAL_INSTRUCTION:
      std::cerr << "EXCEPTION_ILLEGAL_INSTRUCTION";
      break;
    case EXCEPTION_IN_PAGE_ERROR:
      std::cerr << "EXCEPTION_IN_PAGE_ERROR";
      break;
    case EXCEPTION_INT_DIVIDE_BY_ZERO:
      std::cerr << "EXCEPTION_INT_DIVIDE_BY_ZERO";
      break;
    case EXCEPTION_INT_OVERFLOW:
      std::cerr << "EXCEPTION_INT_OVERFLOW";
      break;
    case EXCEPTION_INVALID_DISPOSITION:
      std::cerr << "EXCEPTION_INVALID_DISPOSITION";
      break;
    case EXCEPTION_NONCONTINUABLE_EXCEPTION:
      std::cerr << "EXCEPTION_NONCONTINUABLE_EXCEPTION";
      break;
    case EXCEPTION_PRIV_INSTRUCTION:
      std::cerr << "EXCEPTION_PRIV_INSTRUCTION";
      break;
    case EXCEPTION_SINGLE_STEP:
      std::cerr << "EXCEPTION_SINGLE_STEP";
      break;
    case EXCEPTION_STACK_OVERFLOW:
      std::cerr << "EXCEPTION_STACK_OVERFLOW";
      break;
    default:
      std::cerr << base::StringPrintf("0x%08x", exc_code);
      break;
  }
  std::cerr << "\n";

  debug::StackTrace(info).Print();
  if (g_previous_filter) {
    return g_previous_filter(info);
  }
  return EXCEPTION_CONTINUE_SEARCH;
}

// Not using PathService as stack traces might be needed where that is not
// available.
FilePath GetExePath() {
  std::array<wchar_t, MAX_PATH> system_buffer;
  ::GetModuleFileName(nullptr, system_buffer.data(), system_buffer.size());
  system_buffer.back() = L'\0';
  return FilePath(system_buffer.data());
}

constexpr size_t kSymInitializeRetryCount = 3;

// A wrapper for SymInitialize. SymInitialize seems to occasionally fail
// because of an internal race condition. So  wrap it and retry a finite
// number of times.
// See crbug.com/1339753
bool SymInitializeWrapper(HANDLE handle, BOOL invade_process) {
  for (size_t i = 0; i < kSymInitializeRetryCount; ++i) {
    if (SymInitialize(handle, nullptr, invade_process)) {
      return true;
    }

    g_init_error = GetLastError();
    if (g_init_error != g_status_info_length_mismatch) {
      return false;
    }
  }
  DLOG(ERROR) << "SymInitialize failed repeatedly.";
  return false;
}

bool SymInitializeCurrentProc() {
  const HANDLE current_process = GetCurrentProcess();
  if (SymInitializeWrapper(current_process, TRUE)) {
    return true;
  }

  // g_init_error is updated by SymInitializeWrapper.
  // No need to do "g_init_error = GetLastError()" here.
  if (g_init_error != ERROR_INVALID_PARAMETER) {
    return false;
  }

  // SymInitialize() can fail with ERROR_INVALID_PARAMETER when something has
  // already called SymInitialize() in this process. For example, when absl
  // support for gtest is enabled, it results in absl calling SymInitialize()
  // almost immediately after startup. In such a case, try to reinit to see if
  // that succeeds.
  SymCleanup(current_process);
  if (SymInitializeWrapper(current_process, TRUE)) {
    return true;
  }

  return false;
}

bool MaybeLoadDbghelp() {
  // Check if dbghelp is already loaded.
  HANDLE dbghelp_handle = ::GetModuleHandle(L"dbghelp.dll");
  if (!dbghelp_handle) {
    // Probe to load dbghelp. This may fail in some sandboxes.
    dbghelp_handle = ::LoadLibrary(L"dbghelp.dll");
  }
  if (!dbghelp_handle) {
    return false;
  }
  // If the module is loaded, force resolve delayloads.
  auto loaded = base::win::LoadAllImportsForDll("dbghelp.dll");
  // In tests where dbghelp is not delayloaded this can safely be 'false', a
  // failure only occurs when an error code is returned.
  return loaded.has_value();
}

bool InitializeSymbols() {
  static bool has_dbghelp = MaybeLoadDbghelp();
  if (!has_dbghelp) {
    return false;
  }

  if (g_initialized_symbols) {
    // Force a reinitialization. Will ensure any modules loaded after process
    // startup also get symbolized.
    SymCleanup(GetCurrentProcess());
    g_initialized_symbols = false;
  }
  g_initialized_symbols = true;
  // Defer symbol load until they're needed, use undecorated names, and get line
  // numbers.
  SymSetOptions(SYMOPT_DEFERRED_LOADS | SYMOPT_UNDNAME | SYMOPT_LOAD_LINES);
  if (!SymInitializeCurrentProc()) {
    // When it fails, we should not call debugbreak since it kills the current
    // process (prevents future tests from running or kills the browser
    // process).
    DLOG(ERROR) << "SymInitialize failed: " << g_init_error;
    return false;
  }

  // When transferring the binaries e.g. between bots, path put
  // into the executable will get off. To still retrieve symbols correctly,
  // add the directory of the executable to symbol search path.
  // All following errors are non-fatal.
  static constexpr size_t kSymbolsArraySize = 1024;
  wchar_t symbols_path[kSymbolsArraySize];

  // Note: The below function takes buffer size as number of characters,
  // not number of bytes!
  if (!SymGetSearchPathW(GetCurrentProcess(), symbols_path,
                         kSymbolsArraySize)) {
    g_init_error = GetLastError();
    DLOG(WARNING) << "SymGetSearchPath failed: " << g_init_error;
    return false;
  }

  std::wstring new_path =
      StrCat({symbols_path, L";", GetExePath().DirName().value()});
  if (!SymSetSearchPathW(GetCurrentProcess(), new_path.c_str())) {
    g_init_error = GetLastError();
    DLOG(WARNING) << "SymSetSearchPath failed." << g_init_error;
    return false;
  }

  g_init_error = ERROR_SUCCESS;
  return true;
}

// SymbolContext is a threadsafe singleton that wraps the DbgHelp Sym* family
// of functions.  The Sym* family of functions may only be invoked by one
// thread at a time.  SymbolContext code may access a symbol server over the
// network while holding the lock for this singleton.  In the case of high
// latency, this code will adversely affect performance.
//
// There is also a known issue where this backtrace code can interact
// badly with breakpad if breakpad is invoked in a separate thread while
// we are using the Sym* functions.  This is because breakpad does now
// share a lock with this function.  See this related bug:
//
//   https://crbug.com/google-breakpad/311
//
// This is a very unlikely edge case, and the current solution is to
// just ignore it.
class SymbolContext {
 public:
  static SymbolContext* GetInstance() {
    // We use a leaky singleton because code may call this during process
    // termination.
    return Singleton<SymbolContext, LeakySingletonTraits<SymbolContext>>::get();
  }

  SymbolContext(const SymbolContext&) = delete;
  SymbolContext& operator=(const SymbolContext&) = delete;

  // For the given trace, attempts to resolve the symbols, and output a trace
  // to the ostream os.  The format for each line of the backtrace is:
  //
  //    <tab>SymbolName[0xAddress+Offset] (FileName:LineNo)
  //
  // This function should only be called if Init() has been called.  We do not
  // LOG(FATAL) here because this code is called might be triggered by a
  // LOG(FATAL) itself. Also, it should not be calling complex code that is
  // extensible like PathService since that can in turn fire CHECKs.
  void OutputTraceToStream(base::span<const void* const> traces,
                           std::ostream* os,
                           cstring_view prefix_string) {
    AutoLock lock(lock_);

    IMAGEHLP_MODULE64 module_info{.SizeOfStruct = sizeof(IMAGEHLP_MODULE64)};
    for (size_t i = 0; (i < traces.size()) && os->good(); ++i) {
      const int kMaxNameLength = 256;
      DWORD_PTR frame = reinterpret_cast<DWORD_PTR>(traces[i]);

      // Code adapted from MSDN example:
      // http://msdn.microsoft.com/en-us/library/ms680578(VS.85).aspx
      ULONG64 buffer[(sizeof(SYMBOL_INFO) + kMaxNameLength * sizeof(wchar_t) +
                      sizeof(ULONG64) - 1) /
                     sizeof(ULONG64)] = {};

      // Initialize symbol information retrieval structures.
      DWORD64 sym_displacement = 0;
      PSYMBOL_INFO symbol = reinterpret_cast<PSYMBOL_INFO>(&buffer[0]);
      symbol->SizeOfStruct = sizeof(SYMBOL_INFO);
      symbol->MaxNameLen = kMaxNameLength - 1;

      // Avoid calling Sym functions in sandboxes where dbghelp is not loaded.
      BOOL has_symbol = use_dbghelp() && SymFromAddr(GetCurrentProcess(), frame,
                                                     &sym_displacement, symbol);

      // Attempt to retrieve line number information.
      DWORD line_displacement = 0;
      IMAGEHLP_LINE64 line = {};
      line.SizeOfStruct = sizeof(IMAGEHLP_LINE64);
      BOOL has_line =
          use_dbghelp() && SymGetLineFromAddr64(GetCurrentProcess(), frame,
                                                &line_displacement, &line);

      // Attempt to retrieve the module information.
      BOOL has_module =
          use_dbghelp() &&
          SymGetModuleInfo64(GetCurrentProcess(), frame, &module_info);

      // Output the backtrace line.
      (*os) << prefix_string << "\t";
      if (has_module) {  // Start with the module name (if found).
        (*os) << module_info.ModuleName << "!";
      }
      if (has_symbol) {
        (*os) << symbol->Name << " "
              << base::StringPrintf("[%p+%x]", traces[i], sym_displacement);
      } else {
        // If there is no symbol information, add a spacer.
        (*os) << "(No symbol) " << base::StringPrintf("[%p]", traces[i]);
      }
      if (has_line) {
        (*os) << " (" << line.FileName << ":"
              << base::StringPrintf("%lu", line.LineNumber) << ")";
      }
      (*os) << "\n";
    }
  }

  bool use_dbghelp() const { return g_should_use_dbghelp && has_dbghelp_; }

 private:
  friend struct DefaultSingletonTraits<SymbolContext>;

  SymbolContext() { has_dbghelp_ = InitializeSymbols(); }

  bool has_dbghelp_ = false;
  Lock lock_;
};

}  // namespace

bool EnableInProcessStackDumping() {
  // Add stack dumping support on exception on Windows. Similar to OS_POSIX
  // signal() handling in process_util_posix.cc.
  g_previous_filter = SetUnhandledExceptionFilter(&StackDumpExceptionFilter);

  // Need to initialize symbols early in the process or else this fails on
  // swarming (since symbols are in different directory than in the exes) and
  // also release x64.
  SymbolContext* context = SymbolContext::GetInstance();
  // Allow tests to turn symbols on again.
  g_should_use_dbghelp = true;
  return context->use_dbghelp();
}

bool DisableInProcessStackDumpingForTesting() {
  g_previous_filter = SetUnhandledExceptionFilter(g_previous_filter);
  g_should_use_dbghelp = false;
  return true;
}

bool InProcessStackDumpingEnabledForTesting() {
  SymbolContext* context = SymbolContext::GetInstance();
  return context->use_dbghelp();
}

NOINLINE size_t CollectStackTrace(span<const void*> trace) {
  // When walking our own stack, use CaptureStackBackTrace().
  return CaptureStackBackTrace(0, trace.size(),
                               const_cast<void**>(trace.data()), NULL);
}

StackTrace::StackTrace(EXCEPTION_POINTERS* exception_pointers) {
  InitTrace(exception_pointers->ContextRecord);
}

StackTrace::StackTrace(const CONTEXT* context) {
  InitTrace(context);
}

void StackTrace::InitTrace(const CONTEXT* context_record) {
  if (ShouldSuppressOutput()) {
    CHECK_EQ(count_, 0U);
    std::ranges::fill(trace_, nullptr);
    return;
  }

  // StackWalk64 modifies the register context in place, so we have to copy it
  // so that downstream exception handlers get the right context.  The incoming
  // context may have had more register state (YMM, etc) than we need to unwind
  // the stack. Typically StackWalk64 only needs integer and control registers.
  CONTEXT context_copy = *context_record;
  context_copy.ContextFlags = CONTEXT_INTEGER | CONTEXT_CONTROL;

  // When walking an exception stack, we need to use StackWalk64().
  count_ = 0;
  // Initialize stack walking.
  STACKFRAME64 stack_frame = {};
#if defined(ARCH_CPU_X86_64)
  DWORD machine_type = IMAGE_FILE_MACHINE_AMD64;
  stack_frame.AddrPC.Offset = context_record->Rip;
  stack_frame.AddrFrame.Offset = context_record->Rbp;
  stack_frame.AddrStack.Offset = context_record->Rsp;
#elif defined(ARCH_CPU_ARM64)
  DWORD machine_type = IMAGE_FILE_MACHINE_ARM64;
  stack_frame.AddrPC.Offset = context_record->Pc;
  stack_frame.AddrFrame.Offset = context_record->Fp;
  stack_frame.AddrStack.Offset = context_record->Sp;
#elif defined(ARCH_CPU_X86)
  DWORD machine_type = IMAGE_FILE_MACHINE_I386;
  stack_frame.AddrPC.Offset = context_record->Eip;
  stack_frame.AddrFrame.Offset = context_record->Ebp;
  stack_frame.AddrStack.Offset = context_record->Esp;
#else
#error Unsupported Windows Arch
#endif
  stack_frame.AddrPC.Mode = AddrModeFlat;
  stack_frame.AddrFrame.Mode = AddrModeFlat;
  stack_frame.AddrStack.Mode = AddrModeFlat;
  while (StackWalk64(machine_type, GetCurrentProcess(), GetCurrentThread(),
                     &stack_frame, &context_copy, NULL,
                     &SymFunctionTableAccess64, &SymGetModuleBase64, NULL) &&
         count_ < std::size(trace_)) {
    trace_[count_++] = reinterpret_cast<void*>(stack_frame.AddrPC.Offset);
  }

  std::ranges::fill(span(trace_).last(trace_.size() - count_), nullptr);
}

// static
void StackTrace::PrintMessageWithPrefix(cstring_view prefix_string,
                                        cstring_view message) {
  std::cerr << prefix_string << message;
}

void StackTrace::PrintWithPrefixImpl(cstring_view prefix_string) const {
  OutputToStreamWithPrefixImpl(&std::cerr, prefix_string);
}

void StackTrace::OutputToStreamWithPrefixImpl(
    std::ostream* os,
    cstring_view prefix_string) const {
  SymbolContext* context = SymbolContext::GetInstance();
  if (!context->use_dbghelp()) {
    // In developer builds call base::debug::EnableInProcessStackDumping()
    // before sandbox lockdown to allow best-efforts symbolization.
    (*os) << "Symbols not available. Dumping unresolved backtrace:\n";
  }
  context->OutputTraceToStream(addresses(), os, prefix_string);
}

}  // namespace base::debug