src: allow per-Environment set of env vars

Abstract the `process.env` backing mechanism in C++ to allow
different kinds of backing stores for `process.env` for different
Environments.

PR-URL: #26544
Fixes: #24947
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Signed-off-by: Beth Griggs <Bethany.Griggs@uk.ibm.com>

src/env-inl.h

@@ -447,6 +447,14 @@ inline uint64_t Environment::timer_base() const {
  return timer_base_;
 }
 
+inline std::shared_ptr<KVStore> Environment::envvars() {
+ return envvars_;
+}
+
+inline void Environment::set_envvars(std::shared_ptr<KVStore> envvars) {
+ envvars_ = envvars;
+}
+
 inline bool Environment::printed_error() const {
  return printed_error_;
 }

src/env.cc

@@ -207,6 +207,8 @@ Environment::Environment(IsolateData* isolate_data,
  set_as_callback_data_template(templ);
  }
 
+ set_envvars(per_process::real_environment);
+
  // We create new copies of the per-Environment option sets, so that it is
  // easier to modify them after Environment creation. The defaults are
  // part of the per-Isolate option set, for which in turn the defaults are
@@ -250,7 +252,7 @@ Environment::Environment(IsolateData* isolate_data,
  should_abort_on_uncaught_toggle_[0] = 1;
 
  std::string debug_cats;
- credentials::SafeGetenv("NODE_DEBUG_NATIVE", &debug_cats);
+ credentials::SafeGetenv("NODE_DEBUG_NATIVE", &debug_cats, this);
  set_debug_categories(debug_cats, true);
 
  isolate()->GetHeapProfiler()->AddBuildEmbedderGraphCallback(

src/env.h

@@ -532,6 +532,23 @@ class AsyncRequest : public MemoryRetainer {
  std::atomic_bool stopped_ {true};
 };
 
+class KVStore {
+ public:
+ virtual v8::Local<v8::String> Get(v8::Isolate* isolate,
+ v8::Local<v8::String> key) const = 0;
+ virtual void Set(v8::Isolate* isolate,
+ v8::Local<v8::String> key,
+ v8::Local<v8::String> value) = 0;
+ virtual int32_t Query(v8::Isolate* isolate,
+ v8::Local<v8::String> key) const = 0;
+ virtual void Delete(v8::Isolate* isolate, v8::Local<v8::String> key) = 0;
+ virtual v8::Local<v8::Array> Enumerate(v8::Isolate* isolate) const = 0;
+};
+
+namespace per_process {
+extern std::shared_ptr<KVStore> real_environment;
+}
+
 class AsyncHooks {
  public:
  // Reason for both UidFields and Fields are that one is stored as a double*
@@ -781,6 +798,8 @@ class Environment {
  inline ImmediateInfo* immediate_info();
  inline TickInfo* tick_info();
  inline uint64_t timer_base() const;
+ inline std::shared_ptr<KVStore> envvars();
+ inline void set_envvars(std::shared_ptr<KVStore> envvars);
 
  inline IsolateData* isolate_data() const;
 
@@ -1075,6 +1094,7 @@ class Environment {
  ImmediateInfo immediate_info_;
  TickInfo tick_info_;
  const uint64_t timer_base_;
+ std::shared_ptr<KVStore> envvars_;
  bool printed_error_ = false;
  bool emit_env_nonstring_warning_ = true;
  bool emit_err_name_warning_ = true;

src/node_credentials.cc

@@ -15,11 +15,14 @@ using v8::Array;
 using v8::Context;
 using v8::Function;
 using v8::FunctionCallbackInfo;
+using v8::HandleScope;
 using v8::Isolate;
 using v8::Local;
 using v8::MaybeLocal;
+using v8::NewStringType;
 using v8::Object;
 using v8::String;
+using v8::TryCatch;
 using v8::Uint32;
 using v8::Value;
 
@@ -30,13 +33,27 @@ bool linux_at_secure = false;
 namespace credentials {
 
 // Look up environment variable unless running as setuid root.
-bool SafeGetenv(const char* key, std::string* text) {
+bool SafeGetenv(const char* key, std::string* text, Environment* env) {
 #if !defined(__CloudABI__) && !defined(_WIN32)
  if (per_process::linux_at_secure || getuid() != geteuid() ||
  getgid() != getegid())
  goto fail;
 #endif
 
+ if (env != nullptr) {
+ HandleScope handle_scope(env->isolate());
+ TryCatch ignore_errors(env->isolate());
+ MaybeLocal<String> value = env->envvars()->Get(
+ env->isolate(),
+ String::NewFromUtf8(env->isolate(), key, NewStringType::kNormal)
+ .ToLocalChecked());
+ if (value.IsEmpty()) goto fail;
+ String::Utf8Value utf8_value(env->isolate(), value.ToLocalChecked());
+ if (*utf8_value == nullptr) goto fail;
+ *text = std::string(*utf8_value, utf8_value.length());
+ return true;
+ }
+
  {
  Mutex::ScopedLock lock(per_process::env_var_mutex);
  if (const char* value = getenv(key)) {
@@ -52,10 +69,11 @@ bool SafeGetenv(const char* key, std::string* text) {
 
 static void SafeGetenv(const FunctionCallbackInfo<Value>& args) {
  CHECK(args[0]->IsString());
- Isolate* isolate = args.GetIsolate();
+ Environment* env = Environment::GetCurrent(args);
+ Isolate* isolate = env->isolate();
  Utf8Value strenvtag(isolate, args[0]);
  std::string text;
- if (!SafeGetenv(*strenvtag, &text)) return;
+ if (!SafeGetenv(*strenvtag, &text, env)) return;
  Local<Value> result =
  ToV8Value(isolate->GetCurrentContext(), text).ToLocalChecked();
  args.GetReturnValue().Set(result);