#include <cerrno>

#include <cstdarg>

#include "debug_utils-inl.h"

#include "node_errors.h"

#include "node_external_reference.h"

#include "node_internals.h"

#include "node_process-inl.h"

#include "node_report.h"

#include "node_v8_platform-inl.h"

#include "util-inl.h"

namespace node {

using errors::TryCatchScope;

using v8::Boolean;

using v8::Context;

using v8::Exception;

using v8::Function;

using v8::FunctionCallbackInfo;

using v8::HandleScope;

using v8::Int32;

using v8::Isolate;

using v8::Just;

using v8::Local;

using v8::Maybe;

using v8::MaybeLocal;

using v8::Message;

using v8::Object;

using v8::ScriptOrigin;

using v8::StackFrame;

using v8::StackTrace;

using v8::String;

using v8::Undefined;

using v8::Value;

bool IsExceptionDecorated(Environment* env, Local<Value> er) {

if (!er.IsEmpty() && er->IsObject()) {

Local<Object> err_obj = er.As<Object>();

auto maybe_value =

err_obj->GetPrivate(env->context(), env->decorated_private_symbol());

Local<Value> decorated;

return maybe_value.ToLocal(&decorated) && decorated->IsTrue();

}

return false;

}

namespace per_process {

static Mutex tty_mutex;

} // namespace per_process

static std::string GetErrorSource(Isolate* isolate,

Local<Context> context,

Local<Message> message,

bool* added_exception_line) {

MaybeLocal<String> source_line_maybe = message->GetSourceLine(context);

node::Utf8Value encoded_source(isolate, source_line_maybe.ToLocalChecked());

std::string sourceline(*encoded_source, encoded_source.length());

*added_exception_line = false;

// If source maps have been enabled, the exception line will instead be

// added in the JavaScript context:

Environment* env = Environment::GetCurrent(isolate);

const bool has_source_map_url =

!message->GetScriptOrigin().SourceMapurl().IsEmpty();

if (has_source_map_url && env != nullptr && env->source_maps_enabled()) {

return sourceline;

}

if (sourceline.find("node-do-not-add-exception-line") != std::string::npos) {

return sourceline;

}

// Because of how node modules work, all scripts are wrapped with a

// "function (module, exports, __filename, ...) {"

// to provide script local variables.

//

// When reporting errors on the first line of a script, this wrapper

// function is leaked to the user. There used to be a hack here to

// truncate off the first 62 characters, but it caused numerous other

// problems when vm.runIn*Context() methods were used for non-module

// code.

//

// If we ever decide to re-instate such a hack, the following steps

// must be taken:

//

// 1. Pass a flag around to say "this code was wrapped"

// 2. Update the stack frame output so that it is also correct.

//

// It would probably be simpler to add a line rather than add some

// number of characters to the first line, since V8 truncates the

// sourceline to 78 characters, and we end up not providing very much

// useful debugging info to the user if we remove 62 characters.

// Print (filename):(line number): (message).

ScriptOrigin origin = message->GetScriptOrigin();

node::Utf8Value filename(isolate, message->GetScriptResourceName());

const char* filename_string = *filename;

int linenum = message->GetLineNumber(context).FromJust();

int script_start = (linenum - origin.LineOffset()) == 1

? origin.ColumnOffset()

: 0;

int start = message->GetStartColumn(context).FromMaybe(0);

int end = message->GetEndColumn(context).FromMaybe(0);

if (start >= script_start) {

CHECK_GE(end, start);

start -= script_start;

end -= script_start;

}

std::string buf = SPrintF("%s:%i\n%s\n",

filename_string,

linenum,

sourceline.c_str());

CHECK_GT(buf.size(), 0);

*added_exception_line = true;

if (start > end ||

start < 0 ||

static_cast<size_t>(end) > sourceline.size()) {

return buf;

}

constexpr int kUnderlineBufsize = 1020;

char underline_buf[kUnderlineBufsize + 4];

int off = 0;

// Print wavy underline (GetUnderline is deprecated).

for (int i = 0; i < start; i++) {

if (sourceline[i] == '\0' || off >= kUnderlineBufsize) {

break;

}

CHECK_LT(off, kUnderlineBufsize);

underline_buf[off++] = (sourceline[i] == '\t') ? '\t' : ' ';

}

for (int i = start; i < end; i++) {

if (sourceline[i] == '\0' || off >= kUnderlineBufsize) {

break;

}

CHECK_LT(off, kUnderlineBufsize);

underline_buf[off++] = '^';

}

CHECK_LE(off, kUnderlineBufsize);

underline_buf[off++] = '\n';

return buf + std::string(underline_buf, off);

}

void PrintStackTrace(Isolate* isolate, Local<StackTrace> stack) {

for (int i = 0; i < stack->GetFrameCount(); i++) {

Local<StackFrame> stack_frame = stack->GetFrame(isolate, i);

node::Utf8Value fn_name_s(isolate, stack_frame->GetFunctionName());

node::Utf8Value script_name(isolate, stack_frame->GetScriptName());

const int line_number = stack_frame->GetLineNumber();

const int column = stack_frame->GetColumn();

if (stack_frame->IsEval()) {

if (stack_frame->GetScriptId() == Message::kNoScriptIdInfo) {

FPrintF(stderr, " at [eval]:%i:%i\n", line_number, column);

} else {

FPrintF(stderr,

" at [eval] (%s:%i:%i)\n",

*script_name,

line_number,

column);

}

break;

}

if (fn_name_s.length() == 0) {

FPrintF(stderr, " at %s:%i:%i\n", script_name, line_number, column);

} else {

FPrintF(stderr,

" at %s (%s:%i:%i)\n",

fn_name_s,

script_name,

line_number,

column);

}

}

fflush(stderr);

}

void PrintException(Isolate* isolate,

Local<Context> context,

Local<Value> err,

Local<Message> message) {

node::Utf8Value reason(isolate,

err->ToDetailString(context)

.FromMaybe(Local<String>()));

bool added_exception_line = false;

std::string source =

GetErrorSource(isolate, context, message, &added_exception_line);

FPrintF(stderr, "%s\n", source);

FPrintF(stderr, "%s\n", reason);

Local<v8::StackTrace> stack = message->GetStackTrace();

if (!stack.IsEmpty()) PrintStackTrace(isolate, stack);

}

void PrintCaughtException(Isolate* isolate,

Local<Context> context,

const v8::TryCatch& try_catch) {

CHECK(try_catch.HasCaught());

PrintException(isolate, context, try_catch.Exception(), try_catch.Message());

}

void AppendExceptionLine(Environment* env,

Local<Value> er,

Local<Message> message,

enum ErrorHandlingMode mode) {

if (message.IsEmpty()) return;

HandleScope scope(env->isolate());

Local<Object> err_obj;

if (!er.IsEmpty() && er->IsObject()) {

err_obj = er.As<Object>();

// If arrow_message is already set, skip.

auto maybe_value = err_obj->GetPrivate(env->context(),

env->arrow_message_private_symbol());

Local<Value> lvalue;

if (!maybe_value.ToLocal(&lvalue) || lvalue->IsString())

return;

}

bool added_exception_line = false;

std::string source = GetErrorSource(

env->isolate(), env->context(), message, &added_exception_line);

if (!added_exception_line) {

return;

}

MaybeLocal<Value> arrow_str = ToV8Value(env->context(), source);

const bool can_set_arrow = !arrow_str.IsEmpty() && !err_obj.IsEmpty();

// If allocating arrow_str failed, print it out. There's not much else to do.

// If it's not an error, but something needs to be printed out because

// it's a fatal exception, also print it out from here.

// Otherwise, the arrow property will be attached to the object and handled

// by the caller.

if (!can_set_arrow || (mode == FATAL_ERROR && !err_obj->IsNativeError())) {

if (env->printed_error()) return;

Mutex::ScopedLock lock(per_process::tty_mutex);

env->set_printed_error(true);

ResetStdio();

FPrintF(stderr, "\n%s", source);

return;

}

CHECK(err_obj

->SetPrivate(env->context(),

env->arrow_message_private_symbol(),

arrow_str.ToLocalChecked())

.FromMaybe(false));

}

[[noreturn]] void Abort() {

DumpBacktrace(stderr);

fflush(stderr);

ABORT_NO_BACKTRACE();

}

[[noreturn]] void Assert(const AssertionInfo& info) {

std::string name = GetHumanReadableProcessName();

fprintf(stderr,

"%s: %s:%s%s Assertion `%s' failed.\n",

name.c_str(),

info.file_line,

info.function,

*info.function ? ":" : "",

info.message);

fflush(stderr);

Abort();

}

enum class EnhanceFatalException { kEnhance, kDontEnhance };

/**

* Report the exception to the inspector, then print it to stderr.

* This should only be used when the Node.js instance is about to exit

* (i.e. this should be followed by a env->Exit() or an Abort()).

*

* Use enhance_stack = EnhanceFatalException::kDontEnhance

* when it's unsafe to call into JavaScript.

*/

static void ReportFatalException(Environment* env,

Local<Value> error,

Local<Message> message,

EnhanceFatalException enhance_stack) {

if (!env->can_call_into_js())

enhance_stack = EnhanceFatalException::kDontEnhance;

Isolate* isolate = env->isolate();

CHECK(!error.IsEmpty());

CHECK(!message.IsEmpty());

HandleScope scope(isolate);

AppendExceptionLine(env, error, message, FATAL_ERROR);

auto report_to_inspector = [&]() {

#if HAVE_INSPECTOR

env->inspector_agent()->ReportUncaughtException(error, message);

#endif

};

Local<Value> arrow;

Local<Value> stack_trace;

bool decorated = IsExceptionDecorated(env, error);

if (!error->IsObject()) { // We can only enhance actual errors.

report_to_inspector();

stack_trace = Undefined(isolate);

// If error is not an object, AppendExceptionLine() has already print the

// source line and the arrow to stderr.

// TODO(joyeecheung): move that side effect out of AppendExceptionLine().

// It is done just to preserve the source line as soon as possible.

} else {

Local<Object> err_obj = error.As<Object>();

auto enhance_with = [&](Local<Function> enhancer) {

Local<Value> enhanced;

Local<Value> argv[] = {err_obj};

if (!enhancer.IsEmpty() &&

enhancer

->Call(env->context(), Undefined(isolate), arraysize(argv), argv)

.ToLocal(&enhanced)) {

stack_trace = enhanced;

}

};

switch (enhance_stack) {

case EnhanceFatalException::kEnhance: {

enhance_with(env->enhance_fatal_stack_before_inspector());

report_to_inspector();

enhance_with(env->enhance_fatal_stack_after_inspector());

break;

}

case EnhanceFatalException::kDontEnhance: {

USE(err_obj->Get(env->context(), env->stack_string())

.ToLocal(&stack_trace));

report_to_inspector();

break;

}

default:

UNREACHABLE();

}

arrow =

err_obj->GetPrivate(env->context(), env->arrow_message_private_symbol())

.ToLocalChecked();

}

node::Utf8Value trace(env->isolate(), stack_trace);

// range errors have a trace member set to undefined

if (trace.length() > 0 && !stack_trace->IsUndefined()) {

if (arrow.IsEmpty() || !arrow->IsString() || decorated) {

FPrintF(stderr, "%s\n", trace);

} else {

node::Utf8Value arrow_string(env->isolate(), arrow);

FPrintF(stderr, "%s\n%s\n", arrow_string, trace);

}

} else {

// this really only happens for RangeErrors, since they're the only

// kind that won't have all this info in the trace, or when non-Error

// objects are thrown manually.

MaybeLocal<Value> message;

MaybeLocal<Value> name;

if (error->IsObject()) {

Local<Object> err_obj = error.As<Object>();

message = err_obj->Get(env->context(), env->message_string());

name = err_obj->Get(env->context(), env->name_string());

}

if (message.IsEmpty() || message.ToLocalChecked()->IsUndefined() ||

name.IsEmpty() || name.ToLocalChecked()->IsUndefined()) {

// Not an error object. Just print as-is.

node::Utf8Value message(env->isolate(), error);

FPrintF(stderr, "%s\n",

*message ? message.ToString() : "<toString() threw exception>");

} else {

node::Utf8Value name_string(env->isolate(), name.ToLocalChecked());

node::Utf8Value message_string(env->isolate(), message.ToLocalChecked());

if (arrow.IsEmpty() || !arrow->IsString() || decorated) {

FPrintF(stderr, "%s: %s\n", name_string, message_string);

} else {

node::Utf8Value arrow_string(env->isolate(), arrow);

FPrintF(stderr,

"%s\n%s: %s\n", arrow_string, name_string, message_string);

}

}

if (!env->options()->trace_uncaught) {

std::string argv0;

if (!env->argv().empty()) argv0 = env->argv()[0];

if (argv0.empty()) argv0 = "node";

FPrintF(stderr,

"(Use `%s --trace-uncaught ...` to show where the exception "

"was thrown)\n",

fs::Basename(argv0, ".exe"));

}

}

if (env->options()->trace_uncaught) {

Local<StackTrace> trace = message->GetStackTrace();

if (!trace.IsEmpty()) {

FPrintF(stderr, "Thrown at:\n");

PrintStackTrace(env->isolate(), trace);

}

}

if (env->options()->extra_info_on_fatal_exception) {

FPrintF(stderr, "\nNode.js %s\n", NODE_VERSION);

}

fflush(stderr);

}

[[noreturn]] void FatalError(const char* location, const char* message) {

OnFatalError(location, message);

// to suppress compiler warning

ABORT();

}

void OnFatalError(const char* location, const char* message) {

if (location) {

FPrintF(stderr, "FATAL ERROR: %s %s\n", location, message);

} else {

FPrintF(stderr, "FATAL ERROR: %s\n", message);

}

Isolate* isolate = Isolate::TryGetCurrent();

Environment* env = nullptr;

if (isolate != nullptr) {

env = Environment::GetCurrent(isolate);

}

bool report_on_fatalerror;

{

Mutex::ScopedLock lock(node::per_process::cli_options_mutex);

report_on_fatalerror = per_process::cli_options->report_on_fatalerror;

}

if (report_on_fatalerror) {

report::TriggerNodeReport(

isolate, env, message, "FatalError", "", Local<Object>());

}

fflush(stderr);

ABORT();

}

namespace errors {

TryCatchScope::~TryCatchScope() {

if (HasCaught() && !HasTerminated() && mode_ == CatchMode::kFatal) {

HandleScope scope(env_->isolate());

Local<v8::Value> exception = Exception();

Local<v8::Message> message = Message();

EnhanceFatalException enhance = CanContinue() ?

EnhanceFatalException::kEnhance : EnhanceFatalException::kDontEnhance;

if (message.IsEmpty())

message = Exception::CreateMessage(env_->isolate(), exception);

ReportFatalException(env_, exception, message, enhance);

env_->Exit(7);

}

}

const char* errno_string(int errorno) {

#define ERRNO_CASE(e) \

case e: \

return #e;

switch (errorno) {

#ifdef EACCES

ERRNO_CASE(EACCES);

#endif

#ifdef EADDRINUSE

ERRNO_CASE(EADDRINUSE);

#endif

#ifdef EADDRNOTAVAIL

ERRNO_CASE(EADDRNOTAVAIL);

#endif

#ifdef EAFNOSUPPORT

ERRNO_CASE(EAFNOSUPPORT);

#endif

#ifdef EAGAIN

ERRNO_CASE(EAGAIN);

#endif

#ifdef EWOULDBLOCK

#if EAGAIN != EWOULDBLOCK

ERRNO_CASE(EWOULDBLOCK);

#endif

#endif

#ifdef EALREADY

ERRNO_CASE(EALREADY);

#endif

#ifdef EBADF

ERRNO_CASE(EBADF);

#endif

#ifdef EBADMSG

ERRNO_CASE(EBADMSG);

#endif

#ifdef EBUSY

ERRNO_CASE(EBUSY);

#endif

#ifdef ECANCELED

ERRNO_CASE(ECANCELED);

#endif

#ifdef ECHILD

ERRNO_CASE(ECHILD);

#endif

#ifdef ECONNABORTED

ERRNO_CASE(ECONNABORTED);

#endif

#ifdef ECONNREFUSED

ERRNO_CASE(ECONNREFUSED);

#endif

#ifdef ECONNRESET

ERRNO_CASE(ECONNRESET);

#endif

#ifdef EDEADLK

ERRNO_CASE(EDEADLK);

#endif

#ifdef EDESTADDRREQ

ERRNO_CASE(EDESTADDRREQ);

#endif

#ifdef EDOM

ERRNO_CASE(EDOM);

#endif

#ifdef EDQUOT

ERRNO_CASE(EDQUOT);

#endif

#ifdef EEXIST

ERRNO_CASE(EEXIST);

#endif

#ifdef EFAULT

ERRNO_CASE(EFAULT);

#endif

#ifdef EFBIG

ERRNO_CASE(EFBIG);

#endif

#ifdef EHOSTUNREACH

ERRNO_CASE(EHOSTUNREACH);

#endif

#ifdef EIDRM

ERRNO_CASE(EIDRM);

#endif

#ifdef EILSEQ

ERRNO_CASE(EILSEQ);

#endif

#ifdef EINPROGRESS

ERRNO_CASE(EINPROGRESS);

#endif

#ifdef EINTR

ERRNO_CASE(EINTR);

#endif

#ifdef EINVAL

ERRNO_CASE(EINVAL);

#endif

#ifdef EIO

ERRNO_CASE(EIO);

#endif

#ifdef EISCONN

ERRNO_CASE(EISCONN);

#endif

#ifdef EISDIR

ERRNO_CASE(EISDIR);

#endif

#ifdef ELOOP

ERRNO_CASE(ELOOP);

#endif

#ifdef EMFILE

ERRNO_CASE(EMFILE);

#endif

#ifdef EMLINK

ERRNO_CASE(EMLINK);

#endif

#ifdef EMSGSIZE

ERRNO_CASE(EMSGSIZE);

#endif

#ifdef EMULTIHOP

ERRNO_CASE(EMULTIHOP);

#endif

#ifdef ENAMETOOLONG

ERRNO_CASE(ENAMETOOLONG);

#endif

#ifdef ENETDOWN

ERRNO_CASE(ENETDOWN);

#endif

#ifdef ENETRESET

ERRNO_CASE(ENETRESET);

#endif

#ifdef ENETUNREACH

ERRNO_CASE(ENETUNREACH);

#endif

#ifdef ENFILE

ERRNO_CASE(ENFILE);

#endif

#ifdef ENOBUFS

ERRNO_CASE(ENOBUFS);

#endif

#ifdef ENODATA

ERRNO_CASE(ENODATA);

#endif

#ifdef ENODEV

ERRNO_CASE(ENODEV);

#endif

#ifdef ENOENT

ERRNO_CASE(ENOENT);

#endif

#ifdef ENOEXEC

ERRNO_CASE(ENOEXEC);

#endif

#ifdef ENOLINK

ERRNO_CASE(ENOLINK);

#endif

#ifdef ENOLCK

#if ENOLINK != ENOLCK

ERRNO_CASE(ENOLCK);

#endif

#endif

#ifdef ENOMEM

ERRNO_CASE(ENOMEM);

#endif

#ifdef ENOMSG

ERRNO_CASE(ENOMSG);

#endif

#ifdef ENOPROTOOPT

ERRNO_CASE(ENOPROTOOPT);

#endif

#ifdef ENOSPC

ERRNO_CASE(ENOSPC);

#endif

#ifdef ENOSR

ERRNO_CASE(ENOSR);

#endif

#ifdef ENOSTR

ERRNO_CASE(ENOSTR);

#endif

#ifdef ENOSYS

ERRNO_CASE(ENOSYS);

#endif

#ifdef ENOTCONN

ERRNO_CASE(ENOTCONN);

#endif

#ifdef ENOTDIR

ERRNO_CASE(ENOTDIR);

#endif

#ifdef ENOTEMPTY

#if ENOTEMPTY != EEXIST

ERRNO_CASE(ENOTEMPTY);

#endif

#endif

#ifdef ENOTSOCK

ERRNO_CASE(ENOTSOCK);

#endif

#ifdef ENOTSUP

ERRNO_CASE(ENOTSUP);

#else

#ifdef EOPNOTSUPP

ERRNO_CASE(EOPNOTSUPP);

#endif

#endif

#ifdef ENOTTY

ERRNO_CASE(ENOTTY);

#endif

#ifdef ENXIO

ERRNO_CASE(ENXIO);

#endif

#ifdef EOVERFLOW

ERRNO_CASE(EOVERFLOW);

#endif

#ifdef EPERM

ERRNO_CASE(EPERM);

#endif

#ifdef EPIPE

ERRNO_CASE(EPIPE);

#endif

#ifdef EPROTO

ERRNO_CASE(EPROTO);

#endif

#ifdef EPROTONOSUPPORT

ERRNO_CASE(EPROTONOSUPPORT);

#endif

#ifdef EPROTOTYPE

ERRNO_CASE(EPROTOTYPE);

#endif

#ifdef ERANGE

ERRNO_CASE(ERANGE);

#endif

#ifdef EROFS

ERRNO_CASE(EROFS);

#endif

#ifdef ESPIPE

ERRNO_CASE(ESPIPE);

#endif

#ifdef ESRCH

ERRNO_CASE(ESRCH);

#endif

#ifdef ESTALE

ERRNO_CASE(ESTALE);

#endif

#ifdef ETIME

ERRNO_CASE(ETIME);

#endif

#ifdef ETIMEDOUT

ERRNO_CASE(ETIMEDOUT);

#endif

#ifdef ETXTBSY

ERRNO_CASE(ETXTBSY);

#endif

#ifdef EXDEV

ERRNO_CASE(EXDEV);

#endif

default:

return "";

}

}

void PerIsolateMessageListener(Local<Message> message, Local<Value> error) {

Isolate* isolate = message->GetIsolate();

switch (message->ErrorLevel()) {

case Isolate::MessageErrorLevel::kMessageWarning: {

Environment* env = Environment::GetCurrent(isolate);

if (!env) {

break;

}

Utf8Value filename(isolate, message->GetScriptOrigin().ResourceName());

// (filename):(line) (message)

std::stringstream warning;

warning << *filename;

warning << ":";

warning << message->GetLineNumber(env->context()).FromMaybe(-1);

warning << " ";

v8::String::Utf8Value msg(isolate, message->Get());

warning << *msg;

USE(ProcessEmitWarningGeneric(env, warning.str().c_str(), "V8"));

break;

}

case Isolate::MessageErrorLevel::kMessageError:

TriggerUncaughtException(isolate, error, message);

break;

}

}

void SetPrepareStackTraceCallback(const FunctionCallbackInfo<Value>& args) {

Environment* env = Environment::GetCurrent(args);

CHECK(args[0]->IsFunction());

env->set_prepare_stack_trace_callback(args[0].As<Function>());

}

static void SetSourceMapsEnabled(const FunctionCallbackInfo<Value>& args) {

Environment* env = Environment::GetCurrent(args);

CHECK(args[0]->IsBoolean());

env->set_source_maps_enabled(args[0].As<Boolean>()->Value());

}

static void SetEnhanceStackForFatalException(

const FunctionCallbackInfo<Value>& args) {

Environment* env = Environment::GetCurrent(args);

CHECK(args[0]->IsFunction());

CHECK(args[1]->IsFunction());

env->set_enhance_fatal_stack_before_inspector(args[0].As<Function>());

env->set_enhance_fatal_stack_after_inspector(args[1].As<Function>());

}

// Side effect-free stringification that will never throw exceptions.

static void NoSideEffectsToString(const FunctionCallbackInfo<Value>& args) {

Local<Context> context = args.GetIsolate()->GetCurrentContext();

Local<String> detail_string;

if (args[0]->ToDetailString(context).ToLocal(&detail_string))

args.GetReturnValue().Set(detail_string);

}

static void TriggerUncaughtException(const FunctionCallbackInfo<Value>& args) {

Isolate* isolate = args.GetIsolate();

Environment* env = Environment::GetCurrent(isolate);

Local<Value> exception = args[0];

Local<Message> message = Exception::CreateMessage(isolate, exception);

if (env != nullptr && env->abort_on_uncaught_exception()) {

ReportFatalException(

env, exception, message, EnhanceFatalException::kEnhance);

Abort();

}

bool from_promise = args[1]->IsTrue();

errors::TriggerUncaughtException(isolate, exception, message, from_promise);

}

void RegisterExternalReferences(ExternalReferenceRegistry* registry) {

registry->Register(SetPrepareStackTraceCallback);

registry->Register(SetSourceMapsEnabled);

registry->Register(SetEnhanceStackForFatalException);

registry->Register(NoSideEffectsToString);

registry->Register(TriggerUncaughtException);

}

void Initialize(Local<Object> target,

Local<Value> unused,

Local<Context> context,

void* priv) {

Environment* env = Environment::GetCurrent(context);

env->SetMethod(

target, "setPrepareStackTraceCallback", SetPrepareStackTraceCallback);

env->SetMethod(target, "setSourceMapsEnabled", SetSourceMapsEnabled);

env->SetMethod(target,

"setEnhanceStackForFatalException",

SetEnhanceStackForFatalException);

env->SetMethodNoSideEffect(

target, "noSideEffectsToString", NoSideEffectsToString);

env->SetMethod(target, "triggerUncaughtException", TriggerUncaughtException);

}

void DecorateErrorStack(Environment* env,

const errors::TryCatchScope& try_catch) {

Local<Value> exception = try_catch.Exception();

if (!exception->IsObject()) return;

Local<Object> err_obj = exception.As<Object>();

if (IsExceptionDecorated(env, err_obj)) return;

AppendExceptionLine(env, exception, try_catch.Message(), CONTEXTIFY_ERROR);

TryCatchScope try_catch_scope(env); // Ignore exceptions below.

MaybeLocal<Value> stack = err_obj->Get(env->context(), env->stack_string());

MaybeLocal<Value> maybe_value =

err_obj->GetPrivate(env->context(), env->arrow_message_private_symbol());

Local<Value> arrow;

if (!(maybe_value.ToLocal(&arrow) && arrow->IsString())) {

return;

}

if (stack.IsEmpty() || !stack.ToLocalChecked()->IsString()) {

return;

}

Local<String> decorated_stack = String::Concat(

env->isolate(),

String::Concat(env->isolate(),

arrow.As<String>(),

FIXED_ONE_BYTE_STRING(env->isolate(), "\n")),

stack.ToLocalChecked().As<String>());

USE(err_obj->Set(env->context(), env->stack_string(), decorated_stack));

err_obj->SetPrivate(

env->context(), env->decorated_private_symbol(), True(env->isolate()));

}

void TriggerUncaughtException(Isolate* isolate,

Local<Value> error,

Local<Message> message,

bool from_promise) {

CHECK(!error.IsEmpty());

HandleScope scope(isolate);

if (message.IsEmpty()) message = Exception::CreateMessage(isolate, error);

CHECK(isolate->InContext());

Local<Context> context = isolate->GetCurrentContext();

Environment* env = Environment::GetCurrent(context);

if (env == nullptr) {

// This means that the exception happens before Environment is assigned

// to the context e.g. when there is a SyntaxError in a per-context

// script - which usually indicates that there is a bug because no JS

// error is supposed to be thrown at this point.

// Since we don't have access to Environment here, there is not

// much we can do, so we just print whatever is useful and crash.

PrintException(isolate, context, error, message);

Abort();

}

// Invoke process._fatalException() to give user a chance to handle it.

// We have to grab it from the process object since this has been

// monkey-patchable.

Local<Object> process_object = env->process_object();

Local<String> fatal_exception_string = env->fatal_exception_string();

Local<Value> fatal_exception_function =

process_object->Get(env->context(),

fatal_exception_string).ToLocalChecked();

// If the exception happens before process._fatalException is attached

// during bootstrap, or if the user has patched it incorrectly, exit

// the current Node.js instance.

if (!fatal_exception_function->IsFunction()) {

ReportFatalException(

env, error, message, EnhanceFatalException::kDontEnhance);

env->Exit(6);

return;

}

MaybeLocal<Value> maybe_handled;

if (env->can_call_into_js()) {

// We do not expect the global uncaught exception itself to throw any more

// exceptions. If it does, exit the current Node.js instance.

errors::TryCatchScope try_catch(env,

errors::TryCatchScope::CatchMode::kFatal);

// Explicitly disable verbose exception reporting -

// if process._fatalException() throws an error, we don't want it to

// trigger the per-isolate message listener which will call this

// function and recurse.

try_catch.SetVerbose(false);

Local<Value> argv[2] = { error,

Boolean::New(env->isolate(), from_promise) };

maybe_handled = fatal_exception_function.As<Function>()->Call(

env->context(), process_object, arraysize(argv), argv);

}

// If process._fatalException() throws, we are now exiting the Node.js

// instance so return to continue the exit routine.

// TODO(joyeecheung): return a Maybe here to prevent the caller from

// stepping on the exit.

Local<Value> handled;

if (!maybe_handled.ToLocal(&handled)) {

return;

}

// The global uncaught exception handler returns true if the user handles it

// by e.g. listening to `uncaughtException`. In that case, continue program

// execution.