// 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.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40284755): Remove this and spanify to fix the errors.
#pragma allow_unsafe_buffers
#endif
#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/files/file_path.h"
#include "base/logging.h"
#include "base/memory/singleton.h"
#include "base/ranges/algorithm.h"
#include "base/strings/strcat_win.h"
#include "base/strings/string_util.h"
#include "base/synchronization/lock.h"
#include "build/build_config.h"
namespace base {
namespace 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;
// 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 << "0x" << std::hex << exc_code;
break;
}
std::cerr << "\n";
debug::StackTrace(info).Print();
if (g_previous_filter)
return g_previous_filter(info);
return EXCEPTION_CONTINUE_SEARCH;
}
FilePath GetExePath() {
wchar_t system_buffer[MAX_PATH];
GetModuleFileName(NULL, system_buffer, MAX_PATH);
system_buffer[MAX_PATH - 1] = L'\0';
return FilePath(system_buffer);
}
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 InitializeSymbols() {
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_);
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)];
memset(buffer, 0, sizeof(buffer));
// 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;
BOOL has_symbol = 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 = SymGetLineFromAddr64(GetCurrentProcess(), frame,
&line_displacement, &line);
// Output the backtrace line.
(*os) << prefix_string << "\t";
if (has_symbol) {
(*os) << symbol->Name << " [0x" << traces[i] << "+" << sym_displacement
<< "]";
} else {
// If there is no symbol information, add a spacer.
(*os) << "(No symbol) [0x" << traces[i] << "]";
}
if (has_line) {
(*os) << " (" << line.FileName << ":" << line.LineNumber << ")";
}
(*os) << "\n";
}
}
private:
friend struct DefaultSingletonTraits<SymbolContext>;
SymbolContext() {
InitializeSymbols();
}
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.
return InitializeSymbols();
}
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);
base::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;
memcpy(&context_copy, context_record, sizeof(context_copy));
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;
memset(&stack_frame, 0, sizeof(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);
}
base::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 (g_init_error != ERROR_SUCCESS) {
(*os) << "Error initializing symbols (" << g_init_error
<< "). Dumping unresolved backtrace:\n";
for (size_t i = 0; (i < count_) && os->good(); ++i) {
(*os) << prefix_string << "\t" << trace_[i] << "\n";
}
} else {
context->OutputTraceToStream(addresses(), os, prefix_string);
}
}
} // namespace debug
} // namespace base
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