#include "node_binding.h"

#include <atomic>

#include "env-inl.h"

#include "node_errors.h"

#include "node_external_reference.h"

#include "node_native_module_env.h"

#include "util.h"

#include <string>

#if HAVE_OPENSSL

#define NODE_BUILTIN_OPENSSL_MODULES(V) V(crypto) V(tls_wrap)

#else

#define NODE_BUILTIN_OPENSSL_MODULES(V)

#endif

#if NODE_HAVE_I18N_SUPPORT

#define NODE_BUILTIN_ICU_MODULES(V) V(icu)

#else

#define NODE_BUILTIN_ICU_MODULES(V)

#endif

#if HAVE_INSPECTOR

#define NODE_BUILTIN_PROFILER_MODULES(V) V(profiler)

#else

#define NODE_BUILTIN_PROFILER_MODULES(V)

#endif

#if HAVE_DTRACE || HAVE_ETW

#define NODE_BUILTIN_DTRACE_MODULES(V) V(dtrace)

#else

#define NODE_BUILTIN_DTRACE_MODULES(V)

#endif

// A list of built-in modules. In order to do module registration

// in node::Init(), need to add built-in modules in the following list.

// Then in binding::RegisterBuiltinModules(), it calls modules' registration

// function. This helps the built-in modules are loaded properly when

// node is built as static library. No need to depend on the

// __attribute__((constructor)) like mechanism in GCC.

#define NODE_BUILTIN_STANDARD_MODULES(V) \

V(async_wrap) \

V(blob) \

V(block_list) \

V(buffer) \

V(cares_wrap) \

V(config) \

V(contextify) \

V(credentials) \

V(errors) \

V(fs) \

V(fs_dir) \

V(fs_event_wrap) \

V(heap_utils) \

V(http2) \

V(http_parser) \

V(inspector) \

V(js_stream) \

V(js_udp_wrap) \

V(messaging) \

V(module_wrap) \

V(mksnapshot) \

V(native_module) \

V(options) \

V(os) \

V(performance) \

V(pipe_wrap) \

V(process_wrap) \

V(process_methods) \

V(report) \

V(serdes) \

V(signal_wrap) \

V(spawn_sync) \

V(stream_pipe) \

V(stream_wrap) \

V(string_decoder) \

V(symbols) \

V(task_queue) \

V(tcp_wrap) \

V(timers) \

V(trace_events) \

V(tty_wrap) \

V(types) \

V(udp_wrap) \

V(url) \

V(util) \

V(uv) \

V(v8) \

V(wasi) \

V(wasm_web_api) \

V(watchdog) \

V(worker) \

V(zlib)

#define NODE_BUILTIN_MODULES(V) \

NODE_BUILTIN_STANDARD_MODULES(V) \

NODE_BUILTIN_OPENSSL_MODULES(V) \

NODE_BUILTIN_ICU_MODULES(V) \

NODE_BUILTIN_PROFILER_MODULES(V) \

NODE_BUILTIN_DTRACE_MODULES(V)

// This is used to load built-in modules. Instead of using

// __attribute__((constructor)), we call the _register_<modname>

// function for each built-in modules explicitly in

// binding::RegisterBuiltinModules(). This is only forward declaration.

// The definitions are in each module's implementation when calling

// the NODE_MODULE_CONTEXT_AWARE_INTERNAL.

#define V(modname) void _register_##modname();

NODE_BUILTIN_MODULES(V)

#undef V

#ifdef _AIX

// On AIX, dlopen() behaves differently from other operating systems, in that

// it returns unique values from each call, rather than identical values, when

// loading the same handle.

// We try to work around that by providing wrappers for the dlopen() family of

// functions, and using st_dev and st_ino for the file that is to be loaded

// as keys for a cache.

namespace node {

namespace dlwrapper {

struct dl_wrap {

uint64_t st_dev;

uint64_t st_ino;

uint64_t refcount;

void* real_handle;

struct hash {

size_t operator()(const dl_wrap* wrap) const {

return std::hash<uint64_t>()(wrap->st_dev) ^

std::hash<uint64_t>()(wrap->st_ino);

}

};

struct equal {

bool operator()(const dl_wrap* a,

const dl_wrap* b) const {

return a->st_dev == b->st_dev && a->st_ino == b->st_ino;

}

};

};

static Mutex dlhandles_mutex;

static std::unordered_set<dl_wrap*, dl_wrap::hash, dl_wrap::equal>

dlhandles;

static thread_local std::string dlerror_storage;

char* wrapped_dlerror() {

return &dlerror_storage[0];

}

void* wrapped_dlopen(const char* filename, int flags) {

CHECK_NOT_NULL(filename); // This deviates from the 'real' dlopen().

Mutex::ScopedLock lock(dlhandles_mutex);

uv_fs_t req;

auto cleanup = OnScopeLeave([&]() { uv_fs_req_cleanup(&req); });

int rc = uv_fs_stat(nullptr, &req, filename, nullptr);

if (rc != 0) {

dlerror_storage = uv_strerror(rc);

return nullptr;

}

dl_wrap search = {

req.statbuf.st_dev,

req.statbuf.st_ino,

0, nullptr

};

auto it = dlhandles.find(&search);

if (it != dlhandles.end()) {

(*it)->refcount++;

return *it;

}

void* real_handle = dlopen(filename, flags);

if (real_handle == nullptr) {

dlerror_storage = dlerror();

return nullptr;

}

dl_wrap* wrap = new dl_wrap();

wrap->st_dev = req.statbuf.st_dev;

wrap->st_ino = req.statbuf.st_ino;

wrap->refcount = 1;

wrap->real_handle = real_handle;

dlhandles.insert(wrap);

return wrap;

}

int wrapped_dlclose(void* handle) {

Mutex::ScopedLock lock(dlhandles_mutex);

dl_wrap* wrap = static_cast<dl_wrap*>(handle);

int ret = 0;

CHECK_GE(wrap->refcount, 1);

if (--wrap->refcount == 0) {

ret = dlclose(wrap->real_handle);

if (ret != 0) dlerror_storage = dlerror();

dlhandles.erase(wrap);

delete wrap;

}

return ret;

}

void* wrapped_dlsym(void* handle, const char* symbol) {

if (handle == RTLD_DEFAULT || handle == RTLD_NEXT)

return dlsym(handle, symbol);

dl_wrap* wrap = static_cast<dl_wrap*>(handle);

return dlsym(wrap->real_handle, symbol);

}

#define dlopen node::dlwrapper::wrapped_dlopen

#define dlerror node::dlwrapper::wrapped_dlerror

#define dlclose node::dlwrapper::wrapped_dlclose

#define dlsym node::dlwrapper::wrapped_dlsym

} // namespace dlwrapper

} // namespace node

#endif // _AIX

#ifdef __linux__

static bool libc_may_be_musl() {

static std::atomic_bool retval; // Cache the return value.

static std::atomic_bool has_cached_retval { false };

if (has_cached_retval) return retval;

retval = dlsym(RTLD_DEFAULT, "gnu_get_libc_version") == nullptr;

has_cached_retval = true;

return retval;

}

#else // __linux__

static bool libc_may_be_musl() { return false; }

#endif // __linux__

namespace node {

using v8::Context;

using v8::Exception;

using v8::Function;

using v8::FunctionCallbackInfo;

using v8::Local;

using v8::Object;

using v8::String;

using v8::Value;

// Globals per process

static node_module* modlist_internal;

static node_module* modlist_linked;

static thread_local node_module* thread_local_modpending;

// This is set by node::Init() which is used by embedders

bool node_is_initialized = false;

extern "C" void node_module_register(void* m) {

struct node_module* mp = reinterpret_cast<struct node_module*>(m);

if (mp->nm_flags & NM_F_INTERNAL) {

mp->nm_link = modlist_internal;

modlist_internal = mp;

} else if (!node_is_initialized) {

// "Linked" modules are included as part of the node project.

// Like builtins they are registered *before* node::Init runs.

mp->nm_flags = NM_F_LINKED;

mp->nm_link = modlist_linked;

modlist_linked = mp;

} else {

thread_local_modpending = mp;

}

}

namespace binding {

static struct global_handle_map_t {

public:

void set(void* handle, node_module* mod) {

CHECK_NE(handle, nullptr);

Mutex::ScopedLock lock(mutex_);

map_[handle].module = mod;

// We need to store this flag internally to avoid a chicken-and-egg problem

// during cleanup. By the time we actually use the flag's value,

// the shared object has been unloaded, and its memory would be gone,

// making it impossible to access fields of `mod` --

// unless `mod` *is* dynamically allocated, but we cannot know that

// without checking the flag.

map_[handle].wants_delete_module = mod->nm_flags & NM_F_DELETEME;

map_[handle].refcount++;

}

node_module* get_and_increase_refcount(void* handle) {

CHECK_NE(handle, nullptr);

Mutex::ScopedLock lock(mutex_);

auto it = map_.find(handle);

if (it == map_.end()) return nullptr;

it->second.refcount++;

return it->second.module;

}

void erase(void* handle) {

CHECK_NE(handle, nullptr);

Mutex::ScopedLock lock(mutex_);

auto it = map_.find(handle);

if (it == map_.end()) return;

CHECK_GE(it->second.refcount, 1);

if (--it->second.refcount == 0) {

if (it->second.wants_delete_module)

delete it->second.module;

map_.erase(handle);

}

}

private:

Mutex mutex_;

struct Entry {

unsigned int refcount;

bool wants_delete_module;

node_module* module;

};

std::unordered_map<void*, Entry> map_;

} global_handle_map;

DLib::DLib(const char* filename, int flags)

: filename_(filename), flags_(flags), handle_(nullptr) {}

#ifdef __POSIX__

bool DLib::Open() {

handle_ = dlopen(filename_.c_str(), flags_);

if (handle_ != nullptr) return true;

errmsg_ = dlerror();

return false;

}

void DLib::Close() {

if (handle_ == nullptr) return;

if (libc_may_be_musl()) {

// musl libc implements dlclose() as a no-op which returns 0.

// As a consequence, trying to re-load a previously closed addon at a later

// point will not call its static constructors, which Node.js uses.

// Therefore, when we may be using musl libc, we assume that the shared

// object exists indefinitely and keep it in our handle map.

return;

}

int err = dlclose(handle_);

if (err == 0) {

if (has_entry_in_global_handle_map_)

global_handle_map.erase(handle_);

}

handle_ = nullptr;

}

void* DLib::GetSymbolAddress(const char* name) {

return dlsym(handle_, name);

}

#else // !__POSIX__

bool DLib::Open() {

int ret = uv_dlopen(filename_.c_str(), &lib_);

if (ret == 0) {

handle_ = static_cast<void*>(lib_.handle);

return true;

}

errmsg_ = uv_dlerror(&lib_);

uv_dlclose(&lib_);

return false;

}

void DLib::Close() {

if (handle_ == nullptr) return;

if (has_entry_in_global_handle_map_)

global_handle_map.erase(handle_);

uv_dlclose(&lib_);

handle_ = nullptr;

}

void* DLib::GetSymbolAddress(const char* name) {

void* address;

if (0 == uv_dlsym(&lib_, name, &address)) return address;

return nullptr;

}

#endif // !__POSIX__

void DLib::SaveInGlobalHandleMap(node_module* mp) {

has_entry_in_global_handle_map_ = true;

global_handle_map.set(handle_, mp);

}

node_module* DLib::GetSavedModuleFromGlobalHandleMap() {

has_entry_in_global_handle_map_ = true;

return global_handle_map.get_and_increase_refcount(handle_);

}

using InitializerCallback = void (*)(Local<Object> exports,

Local<Value> module,

Local<Context> context);

inline InitializerCallback GetInitializerCallback(DLib* dlib) {

const char* name = "node_register_module_v" STRINGIFY(NODE_MODULE_VERSION);

return reinterpret_cast<InitializerCallback>(dlib->GetSymbolAddress(name));

}

inline napi_addon_register_func GetNapiInitializerCallback(DLib* dlib) {

const char* name =

STRINGIFY(NAPI_MODULE_INITIALIZER_BASE) STRINGIFY(NAPI_MODULE_VERSION);

return reinterpret_cast<napi_addon_register_func>(

dlib->GetSymbolAddress(name));

}

// DLOpen is process.dlopen(module, filename, flags).

// Used to load 'module.node' dynamically shared objects.

//

// FIXME(bnoordhuis) Not multi-context ready. TBD how to resolve the conflict

// when two contexts try to load the same shared object. Maybe have a shadow

// cache that's a plain C list or hash table that's shared across contexts?

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

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

if (env->no_native_addons()) {

return THROW_ERR_DLOPEN_DISABLED(

env, "Cannot load native addon because loading addons is disabled.");

}

auto context = env->context();

CHECK_NULL(thread_local_modpending);

if (args.Length() < 2) {

return THROW_ERR_MISSING_ARGS(

env, "process.dlopen needs at least 2 arguments");

}

int32_t flags = DLib::kDefaultFlags;

if (args.Length() > 2 && !args[2]->Int32Value(context).To(&flags)) {

return THROW_ERR_INVALID_ARG_TYPE(env, "flag argument must be an integer.");

}

Local<Object> module;

Local<Object> exports;

Local<Value> exports_v;

if (!args[0]->ToObject(context).ToLocal(&module) ||

!module->Get(context, env->exports_string()).ToLocal(&exports_v) ||

!exports_v->ToObject(context).ToLocal(&exports)) {

return; // Exception pending.

}

node::Utf8Value filename(env->isolate(), args[1]); // Cast

env->TryLoadAddon(*filename, flags, [&](DLib* dlib) {

static Mutex dlib_load_mutex;

Mutex::ScopedLock lock(dlib_load_mutex);

const bool is_opened = dlib->Open();

// Objects containing v14 or later modules will have registered themselves

// on the pending list. Activate all of them now. At present, only one

// module per object is supported.

node_module* mp = thread_local_modpending;

thread_local_modpending = nullptr;

if (!is_opened) {

std::string errmsg = dlib->errmsg_.c_str();

dlib->Close();

#ifdef _WIN32

// Windows needs to add the filename into the error message

errmsg += *filename;

#endif // _WIN32

THROW_ERR_DLOPEN_FAILED(env, errmsg.c_str());

return false;

}

if (mp != nullptr) {

if (mp->nm_context_register_func == nullptr) {

if (env->force_context_aware()) {

dlib->Close();

THROW_ERR_NON_CONTEXT_AWARE_DISABLED(env);

return false;

}

}

mp->nm_dso_handle = dlib->handle_;

dlib->SaveInGlobalHandleMap(mp);

} else {

if (auto callback = GetInitializerCallback(dlib)) {

callback(exports, module, context);

return true;

} else if (auto napi_callback = GetNapiInitializerCallback(dlib)) {

napi_module_register_by_symbol(exports, module, context, napi_callback);

return true;

} else {

mp = dlib->GetSavedModuleFromGlobalHandleMap();

if (mp == nullptr || mp->nm_context_register_func == nullptr) {

dlib->Close();

char errmsg[1024];

snprintf(errmsg,

sizeof(errmsg),

"Module did not self-register: '%s'.",

*filename);

THROW_ERR_DLOPEN_FAILED(env, errmsg);

return false;

}

}

}

// -1 is used for N-API modules

if ((mp->nm_version != -1) && (mp->nm_version != NODE_MODULE_VERSION)) {

// Even if the module did self-register, it may have done so with the

// wrong version. We must only give up after having checked to see if it

// has an appropriate initializer callback.

if (auto callback = GetInitializerCallback(dlib)) {

callback(exports, module, context);

return true;

}

char errmsg[1024];

snprintf(errmsg,

sizeof(errmsg),

"The module '%s'"

"\nwas compiled against a different Node.js version using"

"\nNODE_MODULE_VERSION %d. This version of Node.js requires"

"\nNODE_MODULE_VERSION %d. Please try re-compiling or "

"re-installing\nthe module (for instance, using `npm rebuild` "

"or `npm install`).",

*filename,

mp->nm_version,

NODE_MODULE_VERSION);

// NOTE: `mp` is allocated inside of the shared library's memory, calling

// `dlclose` will deallocate it

dlib->Close();

THROW_ERR_DLOPEN_FAILED(env, errmsg);

return false;

}

CHECK_EQ(mp->nm_flags & NM_F_BUILTIN, 0);

// Do not keep the lock while running userland addon loading code.

Mutex::ScopedUnlock unlock(lock);

if (mp->nm_context_register_func != nullptr) {

mp->nm_context_register_func(exports, module, context, mp->nm_priv);

} else if (mp->nm_register_func != nullptr) {

mp->nm_register_func(exports, module, mp->nm_priv);

} else {

dlib->Close();

THROW_ERR_DLOPEN_FAILED(env, "Module has no declared entry point.");

return false;

}

return true;

});

// Tell coverity that 'handle' should not be freed when we return.

// coverity[leaked_storage]

}

inline struct node_module* FindModule(struct node_module* list,

const char* name,

int flag) {

struct node_module* mp;

for (mp = list; mp != nullptr; mp = mp->nm_link) {

if (strcmp(mp->nm_modname, name) == 0) break;

}

CHECK(mp == nullptr || (mp->nm_flags & flag) != 0);

return mp;

}

static Local<Object> InitModule(Environment* env,

node_module* mod,

Local<String> module) {

// Internal bindings don't have a "module" object, only exports.

Local<Function> ctor = env->binding_data_ctor_template()

->GetFunction(env->context())

.ToLocalChecked();

Local<Object> exports = ctor->NewInstance(env->context()).ToLocalChecked();

CHECK_NULL(mod->nm_register_func);

CHECK_NOT_NULL(mod->nm_context_register_func);

Local<Value> unused = Undefined(env->isolate());

mod->nm_context_register_func(exports, unused, env->context(), mod->nm_priv);

return exports;

}

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

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

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

Local<String> module = args[0].As<String>();

node::Utf8Value module_v(env->isolate(), module);

Local<Object> exports;

node_module* mod = FindModule(modlist_internal, *module_v, NM_F_INTERNAL);

if (mod != nullptr) {

exports = InitModule(env, mod, module);

env->internal_bindings.insert(mod);

} else if (!strcmp(*module_v, "constants")) {

exports = Object::New(env->isolate());

CHECK(

exports->SetPrototype(env->context(), Null(env->isolate())).FromJust());

DefineConstants(env->isolate(), exports);

} else if (!strcmp(*module_v, "natives")) {

exports = native_module::NativeModuleEnv::GetSourceObject(env->context());

// Legacy feature: process.binding('natives').config contains stringified

// config.gypi

CHECK(exports

->Set(env->context(),

env->config_string(),

native_module::NativeModuleEnv::GetConfigString(

env->isolate()))

.FromJust());

} else {

char errmsg[1024];

snprintf(errmsg, sizeof(errmsg), "No such module: %s", *module_v);

return THROW_ERR_INVALID_MODULE(env, errmsg);

}

args.GetReturnValue().Set(exports);

}

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

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

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

Local<String> module_name = args[0].As<String>();

node::Utf8Value module_name_v(env->isolate(), module_name);

const char* name = *module_name_v;

node_module* mod = nullptr;

// Iterate from here to the nearest non-Worker Environment to see if there's

// a linked binding defined locally rather than through the global list.

Environment* cur_env = env;

while (mod == nullptr && cur_env != nullptr) {

Mutex::ScopedLock lock(cur_env->extra_linked_bindings_mutex());

mod = FindModule(cur_env->extra_linked_bindings_head(), name, NM_F_LINKED);

cur_env = cur_env->worker_parent_env();

}

if (mod == nullptr)

mod = FindModule(modlist_linked, name, NM_F_LINKED);

if (mod == nullptr) {

char errmsg[1024];

snprintf(errmsg,

sizeof(errmsg),

"No such module was linked: %s",

*module_name_v);

return THROW_ERR_INVALID_MODULE(env, errmsg);

}

Local<Object> module = Object::New(env->isolate());

Local<Object> exports = Object::New(env->isolate());

Local<String> exports_prop =

String::NewFromUtf8Literal(env->isolate(), "exports");

module->Set(env->context(), exports_prop, exports).Check();

if (mod->nm_context_register_func != nullptr) {

mod->nm_context_register_func(

exports, module, env->context(), mod->nm_priv);

} else if (mod->nm_register_func != nullptr) {

mod->nm_register_func(exports, module, mod->nm_priv);

} else {

return THROW_ERR_INVALID_MODULE(

env,

"Linked moduled has no declared entry point.");

}

auto effective_exports =

module->Get(env->context(), exports_prop).ToLocalChecked();

args.GetReturnValue().Set(effective_exports);

}

// Call built-in modules' _register_<module name> function to

// do module registration explicitly.

void RegisterBuiltinModules() {

#define V(modname) _register_##modname();

NODE_BUILTIN_MODULES(V)

#undef V

}

void RegisterExternalReferences(ExternalReferenceRegistry* registry) {

registry->Register(GetLinkedBinding);

registry->Register(GetInternalBinding);

}

} // namespace binding

} // namespace node

NODE_MODULE_EXTERNAL_REFERENCE(binding,

node::binding::RegisterExternalReferences)