From 289d86fe8d9c90ce29f7cce72601a88cf02d1660 Mon Sep 17 00:00:00 2001 From: Cheng Zhao Date: Mon, 22 Jan 2024 13:45:55 +0900 Subject: [PATCH] src: preload function for Environment This PR adds a |preload| arg to the node::LoadEnvironment to allow embedders to set a preload function for the environment, which will run after the environment is loaded and before the main script runs. This is similiar to the --require CLI option, but runs a C++ function, and can only be set by embedders. The preload function can be used by embedders to inject scripts before running the main script, for example: 1. In Electron it is used to initialize the ASAR virtual filesystem, inject custom process properties, etc. 2. In VS Code it can be used to reset the module search paths for extensions. --- lib/internal/process/pre_execution.js | 7 +++++++ src/api/environment.cc | 18 +++++++++++------ src/env-inl.h | 8 ++++++++ src/env.h | 4 ++++ src/node.h | 19 ++++++++++++++++-- src/node_options.cc | 6 ++++++ src/node_snapshotable.cc | 9 +++++++++ src/node_worker.cc | 7 ++++++- src/node_worker.h | 1 + test/cctest/test_environment.cc | 28 +++++++++++++++++++++++++++ 10 files changed, 98 insertions(+), 9 deletions(-) diff --git a/lib/internal/process/pre_execution.js b/lib/internal/process/pre_execution.js index 98533b7828d3ff..fd632be10099b0 100644 --- a/lib/internal/process/pre_execution.js +++ b/lib/internal/process/pre_execution.js @@ -186,6 +186,9 @@ function setupUserModules(forceDefaultLoader = false) { initializeESMLoader(forceDefaultLoader); const CJSLoader = require('internal/modules/cjs/loader'); assert(!CJSLoader.hasLoadedAnyUserCJSModule); + if (getEmbedderOptions().hasEmbedderPreload) { + runEmbedderPreload(); + } // Do not enable preload modules if custom loaders are disabled. // For example, loader workers are responsible for doing this themselves. // And preload modules are not supported in ShadowRealm as well. @@ -754,6 +757,10 @@ function initializeFrozenIntrinsics() { } } +function runEmbedderPreload() { + internalBinding('mksnapshot').runEmbedderPreload(process, require); +} + function loadPreloadModules() { // For user code, we preload modules if `-r` is passed const preloadModules = getOptionValue('--require'); diff --git a/src/api/environment.cc b/src/api/environment.cc index 8d7ecad56175ff..5284b18e97fff9 100644 --- a/src/api/environment.cc +++ b/src/api/environment.cc @@ -538,25 +538,31 @@ NODE_EXTERN std::unique_ptr GetInspectorParentHandle( #endif } -MaybeLocal LoadEnvironment( - Environment* env, - StartExecutionCallback cb) { +MaybeLocal LoadEnvironment(Environment* env, + StartExecutionCallback cb, + EmbedderPreloadCallback preload) { env->InitializeLibuv(); env->InitializeDiagnostics(); + if (preload) { + env->set_embedder_preload(std::move(preload)); + } return StartExecution(env, cb); } MaybeLocal LoadEnvironment(Environment* env, - std::string_view main_script_source_utf8) { + std::string_view main_script_source_utf8, + EmbedderPreloadCallback preload) { CHECK_NOT_NULL(main_script_source_utf8.data()); return LoadEnvironment( - env, [&](const StartExecutionCallbackInfo& info) -> MaybeLocal { + env, + [&](const StartExecutionCallbackInfo& info) -> MaybeLocal { Local main_script = ToV8Value(env->context(), main_script_source_utf8).ToLocalChecked(); return info.run_cjs->Call( env->context(), Null(env->isolate()), 1, &main_script); - }); + }, + std::move(preload)); } Environment* GetCurrentEnvironment(Local context) { diff --git a/src/env-inl.h b/src/env-inl.h index 56a96def344194..d86371df12aaac 100644 --- a/src/env-inl.h +++ b/src/env-inl.h @@ -438,6 +438,14 @@ inline void Environment::set_embedder_entry_point(StartExecutionCallback&& fn) { embedder_entry_point_ = std::move(fn); } +inline const EmbedderPreloadCallback& Environment::embedder_preload() const { + return embedder_preload_; +} + +inline void Environment::set_embedder_preload(EmbedderPreloadCallback fn) { + embedder_preload_ = std::move(fn); +} + inline double Environment::new_async_id() { async_hooks()->async_id_fields()[AsyncHooks::kAsyncIdCounter] += 1; return async_hooks()->async_id_fields()[AsyncHooks::kAsyncIdCounter]; diff --git a/src/env.h b/src/env.h index 59ee108e5e8cc1..74c71ac5d95f79 100644 --- a/src/env.h +++ b/src/env.h @@ -1002,6 +1002,9 @@ class Environment : public MemoryRetainer { inline const StartExecutionCallback& embedder_entry_point() const; inline void set_embedder_entry_point(StartExecutionCallback&& fn); + inline const EmbedderPreloadCallback& embedder_preload() const; + inline void set_embedder_preload(EmbedderPreloadCallback fn); + inline void set_process_exit_handler( std::function&& handler); @@ -1208,6 +1211,7 @@ class Environment : public MemoryRetainer { builtins::BuiltinLoader builtin_loader_; StartExecutionCallback embedder_entry_point_; + EmbedderPreloadCallback embedder_preload_; // Used by allocate_managed_buffer() and release_managed_buffer() to keep // track of the BackingStore for a given pointer. diff --git a/src/node.h b/src/node.h index bf3382f4c952ca..3242c96617d33f 100644 --- a/src/node.h +++ b/src/node.h @@ -731,12 +731,27 @@ struct StartExecutionCallbackInfo { using StartExecutionCallback = std::function(const StartExecutionCallbackInfo&)>; +using EmbedderPreloadCallback = + std::function process, + v8::Local require)>; +// Run initialization for the environment. +// +// The |preload| function will run before executing the entry point, which +// is usually used by embedders to inject scripts. The function is executed +// with preload(process, require), and the passed require function has access +// to internal Node.js modules. The |preload| function is inherited by worker +// threads and thus will run in work threads, so make sure the function is +// thread-safe. NODE_EXTERN v8::MaybeLocal LoadEnvironment( Environment* env, - StartExecutionCallback cb); + StartExecutionCallback cb, + EmbedderPreloadCallback preload = nullptr); NODE_EXTERN v8::MaybeLocal LoadEnvironment( - Environment* env, std::string_view main_script_source_utf8); + Environment* env, + std::string_view main_script_source_utf8, + EmbedderPreloadCallback preload = nullptr); NODE_EXTERN void FreeEnvironment(Environment* env); // Set a callback that is called when process.exit() is called from JS, diff --git a/src/node_options.cc b/src/node_options.cc index 7b5152172c5ce7..f4bd5e16402928 100644 --- a/src/node_options.cc +++ b/src/node_options.cc @@ -1304,6 +1304,12 @@ void GetEmbedderOptions(const FunctionCallbackInfo& args) { .IsNothing()) return; + if (ret->Set(context, + FIXED_ONE_BYTE_STRING(env->isolate(), "hasEmbedderPreload"), + Boolean::New(isolate, env->embedder_preload() != nullptr)) + .IsNothing()) + return; + args.GetReturnValue().Set(ret); } diff --git a/src/node_snapshotable.cc b/src/node_snapshotable.cc index c59a4cdccb9c8a..05abc3d418e4b7 100644 --- a/src/node_snapshotable.cc +++ b/src/node_snapshotable.cc @@ -1453,6 +1453,13 @@ static void RunEmbedderEntryPoint(const FunctionCallbackInfo& args) { } } +static void RunEmbedderPreload(const FunctionCallbackInfo& args) { + Environment* env = Environment::GetCurrent(args); + CHECK(env->embedder_preload()); + CHECK_EQ(args.Length(), 2); + env->embedder_preload()(env, args[0], args[1]); +} + void CompileSerializeMain(const FunctionCallbackInfo& args) { CHECK(args[0]->IsString()); Local filename = args[0].As(); @@ -1577,6 +1584,7 @@ void CreatePerIsolateProperties(IsolateData* isolate_data, Local target) { Isolate* isolate = isolate_data->isolate(); SetMethod(isolate, target, "runEmbedderEntryPoint", RunEmbedderEntryPoint); + SetMethod(isolate, target, "runEmbedderPreload", RunEmbedderPreload); SetMethod(isolate, target, "compileSerializeMain", CompileSerializeMain); SetMethod(isolate, target, "setSerializeCallback", SetSerializeCallback); SetMethod(isolate, target, "setDeserializeCallback", SetDeserializeCallback); @@ -1590,6 +1598,7 @@ void CreatePerIsolateProperties(IsolateData* isolate_data, void RegisterExternalReferences(ExternalReferenceRegistry* registry) { registry->Register(RunEmbedderEntryPoint); + registry->Register(RunEmbedderPreload); registry->Register(CompileSerializeMain); registry->Register(SetSerializeCallback); registry->Register(SetDeserializeCallback); diff --git a/src/node_worker.cc b/src/node_worker.cc index 552fdc438a0895..d4424810214787 100644 --- a/src/node_worker.cc +++ b/src/node_worker.cc @@ -63,6 +63,7 @@ Worker::Worker(Environment* env, thread_id_(AllocateEnvironmentThreadId()), name_(name), env_vars_(env_vars), + embedder_preload_(env->embedder_preload()), snapshot_data_(snapshot_data) { Debug(this, "Creating new worker instance with thread id %llu", thread_id_.id); @@ -387,8 +388,12 @@ void Worker::Run() { } Debug(this, "Created message port for worker %llu", thread_id_.id); - if (LoadEnvironment(env_.get(), StartExecutionCallback{}).IsEmpty()) + if (LoadEnvironment(env_.get(), + StartExecutionCallback{}, + std::move(embedder_preload_)) + .IsEmpty()) { return; + } Debug(this, "Loaded environment for worker %llu", thread_id_.id); } diff --git a/src/node_worker.h b/src/node_worker.h index 531e2b5287010f..07fd7b460654e1 100644 --- a/src/node_worker.h +++ b/src/node_worker.h @@ -114,6 +114,7 @@ class Worker : public AsyncWrap { std::unique_ptr child_port_data_; std::shared_ptr env_vars_; + EmbedderPreloadCallback embedder_preload_; // A raw flag that is used by creator and worker threads to // sync up on pre-mature termination of worker - while in the diff --git a/test/cctest/test_environment.cc b/test/cctest/test_environment.cc index 9b812408154287..64e38c83006a00 100644 --- a/test/cctest/test_environment.cc +++ b/test/cctest/test_environment.cc @@ -778,3 +778,31 @@ TEST_F(EnvironmentTest, RequestInterruptAtExit) { context->Exit(); } + +TEST_F(EnvironmentTest, EmbedderPreload) { + v8::HandleScope handle_scope(isolate_); + v8::Local context = node::NewContext(isolate_); + v8::Context::Scope context_scope(context); + + node::EmbedderPreloadCallback preload = [](node::Environment* env, + v8::Local process, + v8::Local require) { + CHECK(process->IsObject()); + CHECK(require->IsFunction()); + process.As() + ->Set(env->context(), + v8::String::NewFromUtf8Literal(env->isolate(), "prop"), + v8::String::NewFromUtf8Literal(env->isolate(), "preload")) + .Check(); + }; + + std::unique_ptr env( + node::CreateEnvironment(isolate_data_, context, {}, {}), + node::FreeEnvironment); + + v8::Local main_ret = + node::LoadEnvironment(env.get(), "return process.prop;", preload) + .ToLocalChecked(); + node::Utf8Value main_ret_str(isolate_, main_ret); + EXPECT_EQ(std::string(*main_ret_str), "preload"); +}