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src: use custom fprintf alike to write errors to stderr
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This allows printing errors that contain nul characters, for example.

Fixes: #28761
Fixes: #31218

PR-URL: #31446
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
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@addaleax @codebytere
addaleax authored and codebytere committed Feb 17, 2020
1 parent a685827 commit 76aad0e
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Showing 9 changed files with 111 additions and 94 deletions.
5 changes: 5 additions & 0 deletions src/debug_utils-inl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,11 @@ std::string COLD_NOINLINE SPrintF( // NOLINT(runtime/string)
return SPrintFImpl(format, std::forward<Args>(args)...);
}

template <typename... Args>
void COLD_NOINLINE FPrintF(FILE* file, const char* format, Args&&... args) {
FWrite(file, SPrintF(format, std::forward<Args>(args)...));
}

} // namespace node

#endif // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
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43 changes: 43 additions & 0 deletions src/debug_utils.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,10 @@
#include <features.h>
#endif

#ifdef __ANDROID__
#include <android/log.h>
#endif

#if defined(__linux__) && !defined(__GLIBC__) || \
defined(__UCLIBC__) || \
defined(_AIX)
Expand Down Expand Up @@ -437,6 +441,45 @@ std::vector<std::string> NativeSymbolDebuggingContext::GetLoadedLibraries() {
return list;
}

void FWrite(FILE* file, const std::string& str) {
auto simple_fwrite = [&]() {
// The return value is ignored because there's no good way to handle it.
fwrite(str.data(), str.size(), 1, file);
};

if (file != stderr && file != stdout) {
simple_fwrite();
return;
}
#ifdef _WIN32
HANDLE handle =
GetStdHandle(file == stdout ? STD_OUTPUT_HANDLE : STD_ERROR_HANDLE);

// Check if stderr is something other than a tty/console
if (handle == INVALID_HANDLE_VALUE || handle == nullptr ||
uv_guess_handle(_fileno(file)) != UV_TTY) {
simple_fwrite();
return;
}

// Get required wide buffer size
int n = MultiByteToWideChar(CP_UTF8, 0, str.data(), str.size(), nullptr, 0);

std::vector<wchar_t> wbuf(n);
MultiByteToWideChar(CP_UTF8, 0, str.data(), str.size(), wbuf.data(), n);

// Don't include the final null character in the output
CHECK_GT(n, 0);
WriteConsoleW(handle, wbuf.data(), n - 1, nullptr, nullptr);
return;
#elif defined(__ANDROID__)
if (file == stderr) {
__android_log_print(ANDROID_LOG_ERROR, "nodejs", "%s", str.data());
return;
}
#endif
simple_fwrite();
}

} // namespace node

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10 changes: 6 additions & 4 deletions src/debug_utils.h
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Original file line number Diff line number Diff line change
Expand Up @@ -25,13 +25,16 @@ namespace node {
template <typename T>
inline std::string ToString(const T& value);

// C++-style variant of sprintf() that:
// C++-style variant of sprintf()/fprintf() that:
// - Returns an std::string
// - Handles \0 bytes correctly
// - Supports %p and %s. %d, %i and %u are aliases for %s.
// - Accepts any class that has a ToString() method for stringification.
template <typename... Args>
inline std::string SPrintF(const char* format, Args&&... args);
template <typename... Args>
inline void FPrintF(FILE* file, const char* format, Args&&... args);
void FWrite(FILE* file, const std::string& str);

template <typename... Args>
inline void FORCE_INLINE Debug(Environment* env,
Expand All @@ -40,16 +43,15 @@ inline void FORCE_INLINE Debug(Environment* env,
Args&&... args) {
if (!UNLIKELY(env->debug_enabled(cat)))
return;
std::string out = SPrintF(format, std::forward<Args>(args)...);
fwrite(out.data(), out.size(), 1, stderr);
FPrintF(stderr, format, std::forward<Args>(args)...);
}

inline void FORCE_INLINE Debug(Environment* env,
DebugCategory cat,
const char* message) {
if (!UNLIKELY(env->debug_enabled(cat)))
return;
fprintf(stderr, "%s", message);
FPrintF(stderr, "%s", message);
}

template <typename... Args>
Expand Down
127 changes: 40 additions & 87 deletions src/node_errors.cc
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Original file line number Diff line number Diff line change
@@ -1,6 +1,7 @@
#include <cerrno>
#include <cstdarg>

#include "debug_utils-inl.h"
#include "node_errors.h"
#include "node_internals.h"
#ifdef NODE_REPORT
Expand All @@ -10,10 +11,6 @@
#include "node_v8_platform-inl.h"
#include "util-inl.h"

#ifdef __ANDROID__
#include <android/log.h>
#endif

namespace node {

using errors::TryCatchScope;
Expand Down Expand Up @@ -54,8 +51,6 @@ namespace per_process {
static Mutex tty_mutex;
} // namespace per_process

static const int kMaxErrorSourceLength = 1024;

static std::string GetErrorSource(Isolate* isolate,
Local<Context> context,
Local<Message> message,
Expand Down Expand Up @@ -107,41 +102,35 @@ static std::string GetErrorSource(Isolate* isolate,
end -= script_start;
}

int max_off = kMaxErrorSourceLength - 2;

char buf[kMaxErrorSourceLength];
int off = snprintf(buf,
kMaxErrorSourceLength,
"%s:%i\n%s\n",
filename_string,
linenum,
sourceline.c_str());
CHECK_GE(off, 0);
if (off > max_off) {
off = max_off;
}
std::string buf = SPrintF("%s:%i\n%s\n",
filename_string,
linenum,
sourceline.c_str());
CHECK_GT(buf.size(), 0);

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 >= max_off) {
if (sourceline[i] == '\0' || off >= kUnderlineBufsize) {
break;
}
CHECK_LT(off, max_off);
buf[off++] = (sourceline[i] == '\t') ? '\t' : ' ';
CHECK_LT(off, kUnderlineBufsize);
underline_buf[off++] = (sourceline[i] == '\t') ? '\t' : ' ';
}
for (int i = start; i < end; i++) {
if (sourceline[i] == '\0' || off >= max_off) {
if (sourceline[i] == '\0' || off >= kUnderlineBufsize) {
break;
}
CHECK_LT(off, max_off);
buf[off++] = '^';
CHECK_LT(off, kUnderlineBufsize);
underline_buf[off++] = '^';
}
CHECK_LE(off, max_off);
buf[off] = '\n';
buf[off + 1] = '\0';
CHECK_LE(off, kUnderlineBufsize);
underline_buf[off++] = '\n';

*added_exception_line = true;
return std::string(buf);
return buf + std::string(underline_buf, off);
}

void PrintStackTrace(Isolate* isolate, Local<StackTrace> stack) {
Expand All @@ -154,9 +143,9 @@ void PrintStackTrace(Isolate* isolate, Local<StackTrace> stack) {

if (stack_frame->IsEval()) {
if (stack_frame->GetScriptId() == Message::kNoScriptIdInfo) {
fprintf(stderr, " at [eval]:%i:%i\n", line_number, column);
FPrintF(stderr, " at [eval]:%i:%i\n", line_number, column);
} else {
fprintf(stderr,
FPrintF(stderr,
" at [eval] (%s:%i:%i)\n",
*script_name,
line_number,
Expand All @@ -166,12 +155,12 @@ void PrintStackTrace(Isolate* isolate, Local<StackTrace> stack) {
}

if (fn_name_s.length() == 0) {
fprintf(stderr, " at %s:%i:%i\n", *script_name, line_number, column);
FPrintF(stderr, " at %s:%i:%i\n", script_name, line_number, column);
} else {
fprintf(stderr,
FPrintF(stderr,
" at %s (%s:%i:%i)\n",
*fn_name_s,
*script_name,
fn_name_s,
script_name,
line_number,
column);
}
Expand All @@ -189,8 +178,8 @@ void PrintException(Isolate* isolate,
bool added_exception_line = false;
std::string source =
GetErrorSource(isolate, context, message, &added_exception_line);
fprintf(stderr, "%s\n", source.c_str());
fprintf(stderr, "%s\n", *reason);
FPrintF(stderr, "%s\n", source);
FPrintF(stderr, "%s\n", reason);

Local<v8::StackTrace> stack = message->GetStackTrace();
if (!stack.IsEmpty()) PrintStackTrace(isolate, stack);
Expand Down Expand Up @@ -235,7 +224,7 @@ void AppendExceptionLine(Environment* env,
env->set_printed_error(true);

ResetStdio();
PrintErrorString("\n%s", source.c_str());
FPrintF(stderr, "\n%s", source);
return;
}

Expand Down Expand Up @@ -350,10 +339,10 @@ static void ReportFatalException(Environment* env,
// range errors have a trace member set to undefined
if (trace.length() > 0 && !stack_trace->IsUndefined()) {
if (arrow.IsEmpty() || !arrow->IsString() || decorated) {
PrintErrorString("%s\n", *trace);
FPrintF(stderr, "%s\n", trace);
} else {
node::Utf8Value arrow_string(env->isolate(), arrow);
PrintErrorString("%s\n%s\n", *arrow_string, *trace);
FPrintF(stderr, "%s\n%s\n", arrow_string, trace);
}
} else {
// this really only happens for RangeErrors, since they're the only
Expand All @@ -371,76 +360,40 @@ static void ReportFatalException(Environment* env,
if (message.IsEmpty() || message.ToLocalChecked()->IsUndefined() ||
name.IsEmpty() || name.ToLocalChecked()->IsUndefined()) {
// Not an error object. Just print as-is.
String::Utf8Value message(env->isolate(), error);
node::Utf8Value message(env->isolate(), error);

PrintErrorString("%s\n",
*message ? *message : "<toString() threw exception>");
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) {
PrintErrorString("%s: %s\n", *name_string, *message_string);
FPrintF(stderr, "%s: %s\n", name_string, message_string);
} else {
node::Utf8Value arrow_string(env->isolate(), arrow);
PrintErrorString(
"%s\n%s: %s\n", *arrow_string, *name_string, *message_string);
FPrintF(stderr,
"%s\n%s: %s\n", arrow_string, name_string, message_string);
}
}

if (!env->options()->trace_uncaught) {
PrintErrorString("(Use `node --trace-uncaught ...` to show "
"where the exception was thrown)\n");
FPrintF(stderr, "(Use `node --trace-uncaught ...` to show "
"where the exception was thrown)\n");
}
}

if (env->options()->trace_uncaught) {
Local<StackTrace> trace = message->GetStackTrace();
if (!trace.IsEmpty()) {
PrintErrorString("Thrown at:\n");
FPrintF(stderr, "Thrown at:\n");
PrintStackTrace(env->isolate(), trace);
}
}

fflush(stderr);
}

void PrintErrorString(const char* format, ...) {
va_list ap;
va_start(ap, format);
#ifdef _WIN32
HANDLE stderr_handle = GetStdHandle(STD_ERROR_HANDLE);

// Check if stderr is something other than a tty/console
if (stderr_handle == INVALID_HANDLE_VALUE || stderr_handle == nullptr ||
uv_guess_handle(_fileno(stderr)) != UV_TTY) {
vfprintf(stderr, format, ap);
va_end(ap);
return;
}

// Fill in any placeholders
int n = _vscprintf(format, ap);
std::vector<char> out(n + 1);
vsprintf(out.data(), format, ap);

// Get required wide buffer size
n = MultiByteToWideChar(CP_UTF8, 0, out.data(), -1, nullptr, 0);

std::vector<wchar_t> wbuf(n);
MultiByteToWideChar(CP_UTF8, 0, out.data(), -1, wbuf.data(), n);

// Don't include the null character in the output
CHECK_GT(n, 0);
WriteConsoleW(stderr_handle, wbuf.data(), n - 1, nullptr, nullptr);
#elif defined(__ANDROID__)
__android_log_vprint(ANDROID_LOG_ERROR, "nodejs", format, ap);
#else
vfprintf(stderr, format, ap);
#endif
va_end(ap);
}

[[noreturn]] void FatalError(const char* location, const char* message) {
OnFatalError(location, message);
// to suppress compiler warning
Expand All @@ -449,9 +402,9 @@ void PrintErrorString(const char* format, ...) {

void OnFatalError(const char* location, const char* message) {
if (location) {
PrintErrorString("FATAL ERROR: %s %s\n", location, message);
FPrintF(stderr, "FATAL ERROR: %s %s\n", location, message);
} else {
PrintErrorString("FATAL ERROR: %s\n", message);
FPrintF(stderr, "FATAL ERROR: %s\n", message);
}
#ifdef NODE_REPORT
Isolate* isolate = Isolate::GetCurrent();
Expand Down
2 changes: 0 additions & 2 deletions src/node_errors.h
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Original file line number Diff line number Diff line change
Expand Up @@ -25,8 +25,6 @@ void AppendExceptionLine(Environment* env,
[[noreturn]] void FatalError(const char* location, const char* message);
void OnFatalError(const char* location, const char* message);

void PrintErrorString(const char* format, ...);

// Helpers to construct errors similar to the ones provided by
// lib/internal/errors.js.
// Example: with `V(ERR_INVALID_ARG_TYPE, TypeError)`, there will be
Expand Down
3 changes: 2 additions & 1 deletion src/node_process_methods.cc
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
#include "base_object-inl.h"
#include "debug_utils-inl.h"
#include "env-inl.h"
#include "node.h"
#include "node_errors.h"
Expand Down Expand Up @@ -216,7 +217,7 @@ void RawDebug(const FunctionCallbackInfo<Value>& args) {
CHECK(args.Length() == 1 && args[0]->IsString() &&
"must be called with a single string");
Utf8Value message(args.GetIsolate(), args[0]);
PrintErrorString("%s\n", *message);
FPrintF(stderr, "%s\n", message);
fflush(stderr);
}

Expand Down
4 changes: 4 additions & 0 deletions src/util.h
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Original file line number Diff line number Diff line change
Expand Up @@ -480,6 +480,8 @@ class ArrayBufferViewContents {
class Utf8Value : public MaybeStackBuffer<char> {
public:
explicit Utf8Value(v8::Isolate* isolate, v8::Local<v8::Value> value);

inline std::string ToString() const { return std::string(out(), length()); }
};

class TwoByteValue : public MaybeStackBuffer<uint16_t> {
Expand All @@ -490,6 +492,8 @@ class TwoByteValue : public MaybeStackBuffer<uint16_t> {
class BufferValue : public MaybeStackBuffer<char> {
public:
explicit BufferValue(v8::Isolate* isolate, v8::Local<v8::Value> value);

inline std::string ToString() const { return std::string(out(), length()); }
};

#define SPREAD_BUFFER_ARG(val, name) \
Expand Down
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