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: https://github.com/nodejs/node/pull/26544
Fixes: https://github.com/nodejs/node/issues/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>

6 files changed, 176 insertions, 84 deletions

diff --git a/src/env-inl.h b/src/env-inl.h
index 69c70804c8..3eedbb857b 100644
--- a/src/env-inl.h
+++ b/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_;
 }
diff --git a/src/env.cc b/src/env.cc
index 174cadcc04..ffdb4289bb 100644
--- a/src/env.cc
+++ b/src/env.cc
@@ -178,6 +178,8 @@ 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
@@ -221,7 +223,7 @@ 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(
diff --git a/src/env.h b/src/env.h
index 743c236827..e6c3a1c037 100644
--- a/src/env.h
+++ b/src/env.h
@@ -540,6 +540,23 @@ 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*
@@ -789,6 +806,8 @@ 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;
diff --git a/src/node_credentials.cc b/src/node_credentials.cc
index 8d38c38a0c..23b9ad2893 100644
--- a/src/node_credentials.cc
+++ b/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 @@ fail:
 
 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);
diff --git a/src/node_env_var.cc b/src/node_env_var.cc
index 7e4913702b..6bd799e19f 100644
--- a/src/node_env_var.cc
+++ b/src/node_env_var.cc
@@ -27,24 +27,29 @@ using v8::PropertyCallbackInfo;
 using v8::String;
 using v8::Value;
 
+class RealEnvStore final : public KVStore {
+ public:
+  Local<String> Get(Isolate* isolate, Local<String> key) const override;
+  void Set(Isolate* isolate, Local<String> key, Local<String> value) override;
+  int32_t Query(Isolate* isolate, Local<String> key) const override;
+  void Delete(Isolate* isolate, Local<String> key) override;
+  Local<Array> Enumerate(Isolate* isolate) const override;
+};
+
 namespace per_process {
 Mutex env_var_mutex;
+std::shared_ptr<KVStore> real_environment = std::make_shared<RealEnvStore>();
 }  // namespace per_process
 
-static void EnvGetter(Local<Name> property,
-                      const PropertyCallbackInfo<Value>& info) {
-  Isolate* isolate = info.GetIsolate();
-  if (property->IsSymbol()) {
-    return info.GetReturnValue().SetUndefined();
-  }
+Local<String> RealEnvStore::Get(Isolate* isolate,
+                                Local<String> property) const {
   Mutex::ScopedLock lock(per_process::env_var_mutex);
 #ifdef __POSIX__
   node::Utf8Value key(isolate, property);
   const char* val = getenv(*key);
   if (val) {
-    return info.GetReturnValue().Set(
-        String::NewFromUtf8(isolate, val, NewStringType::kNormal)
-            .ToLocalChecked());
+    return String::NewFromUtf8(isolate, val, NewStringType::kNormal)
+        .ToLocalChecked();
   }
 #else  // _WIN32
   node::TwoByteValue key(isolate, property);
@@ -62,106 +67,72 @@ static void EnvGetter(Local<Name> property,
         isolate, two_byte_buffer, NewStringType::kNormal);
     if (rc.IsEmpty()) {
       isolate->ThrowException(ERR_STRING_TOO_LONG(isolate));
-      return;
+      return Local<String>();
     }
-    return info.GetReturnValue().Set(rc.ToLocalChecked());
+    return rc.ToLocalChecked();
   }
 #endif
+  return Local<String>();
 }
 
-static void EnvSetter(Local<Name> property,
-                      Local<Value> value,
-                      const PropertyCallbackInfo<Value>& info) {
-  Environment* env = Environment::GetCurrent(info);
-  // calling env->EmitProcessEnvWarning() sets a variable indicating that
-  // warnings have been emitted. It should be called last after other
-  // conditions leading to a warning have been met.
-  if (env->options()->pending_deprecation && !value->IsString() &&
-      !value->IsNumber() && !value->IsBoolean() &&
-      env->EmitProcessEnvWarning()) {
-    if (ProcessEmitDeprecationWarning(
-            env,
-            "Assigning any value other than a string, number, or boolean to a "
-            "process.env property is deprecated. Please make sure to convert "
-            "the "
-            "value to a string before setting process.env with it.",
-            "DEP0104")
-            .IsNothing())
-      return;
-  }
-
+void RealEnvStore::Set(Isolate* isolate,
+                       Local<String> property,
+                       Local<String> value) {
   Mutex::ScopedLock lock(per_process::env_var_mutex);
 #ifdef __POSIX__
-  node::Utf8Value key(info.GetIsolate(), property);
-  node::Utf8Value val(info.GetIsolate(), value);
+  node::Utf8Value key(isolate, property);
+  node::Utf8Value val(isolate, value);
   setenv(*key, *val, 1);
 #else  // _WIN32
-  node::TwoByteValue key(info.GetIsolate(), property);
-  node::TwoByteValue val(info.GetIsolate(), value);
+  node::TwoByteValue key(isolate, property);
+  node::TwoByteValue val(isolate, value);
   WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
   // Environment variables that start with '=' are read-only.
   if (key_ptr[0] != L'=') {
     SetEnvironmentVariableW(key_ptr, reinterpret_cast<WCHAR*>(*val));
   }
 #endif
-  // Whether it worked or not, always return value.
-  info.GetReturnValue().Set(value);
 }
 
-static void EnvQuery(Local<Name> property,
-                     const PropertyCallbackInfo<Integer>& info) {
+int32_t RealEnvStore::Query(Isolate* isolate, Local<String> property) const {
   Mutex::ScopedLock lock(per_process::env_var_mutex);
-  int32_t rc = -1;  // Not found unless proven otherwise.
-  if (property->IsString()) {
 #ifdef __POSIX__
-    node::Utf8Value key(info.GetIsolate(), property);
-    if (getenv(*key)) rc = 0;
+  node::Utf8Value key(isolate, property);
+  if (getenv(*key)) return 0;
 #else  // _WIN32
-    node::TwoByteValue key(info.GetIsolate(), property);
-    WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
-    SetLastError(ERROR_SUCCESS);
-    if (GetEnvironmentVariableW(key_ptr, nullptr, 0) > 0 ||
-        GetLastError() == ERROR_SUCCESS) {
-      rc = 0;
-      if (key_ptr[0] == L'=') {
-        // Environment variables that start with '=' are hidden and read-only.
-        rc = static_cast<int32_t>(v8::ReadOnly) |
+  node::TwoByteValue key(isolate, property);
+  WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
+  SetLastError(ERROR_SUCCESS);
+  if (GetEnvironmentVariableW(key_ptr, nullptr, 0) > 0 ||
+      GetLastError() == ERROR_SUCCESS) {
+    if (key_ptr[0] == L'=') {
+      // Environment variables that start with '=' are hidden and read-only.
+      return static_cast<int32_t>(v8::ReadOnly) |
              static_cast<int32_t>(v8::DontDelete) |
              static_cast<int32_t>(v8::DontEnum);
-      }
     }
-#endif
+    return 0;
   }
-  if (rc != -1) info.GetReturnValue().Set(rc);
+#endif
+  return -1;
 }
 
-static void EnvDeleter(Local<Name> property,
-                       const PropertyCallbackInfo<Boolean>& info) {
+void RealEnvStore::Delete(Isolate* isolate, Local<String> property) {
   Mutex::ScopedLock lock(per_process::env_var_mutex);
-  if (property->IsString()) {
 #ifdef __POSIX__
-    node::Utf8Value key(info.GetIsolate(), property);
-    unsetenv(*key);
+  node::Utf8Value key(isolate, property);
+  unsetenv(*key);
 #else
-    node::TwoByteValue key(info.GetIsolate(), property);
-    WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
-    SetEnvironmentVariableW(key_ptr, nullptr);
+  node::TwoByteValue key(isolate, property);
+  WCHAR* key_ptr = reinterpret_cast<WCHAR*>(*key);
+  SetEnvironmentVariableW(key_ptr, nullptr);
 #endif
-  }
-
-  // process.env never has non-configurable properties, so always
-  // return true like the tc39 delete operator.
-  info.GetReturnValue().Set(true);
 }
 
-static void EnvEnumerator(const PropertyCallbackInfo<Array>& info) {
-  Environment* env = Environment::GetCurrent(info);
-  Isolate* isolate = env->isolate();
-
+Local<Array> RealEnvStore::Enumerate(Isolate* isolate) const {
   Mutex::ScopedLock lock(per_process::env_var_mutex);
-  Local<Array> envarr;
-  int env_size = 0;
 #ifdef __POSIX__
+  int env_size = 0;
   while (environ[env_size]) {
     env_size++;
   }
@@ -177,7 +148,8 @@ static void EnvEnumerator(const PropertyCallbackInfo<Array>& info) {
 #else  // _WIN32
   std::vector<Local<Value>> env_v;
   WCHAR* environment = GetEnvironmentStringsW();
-  if (environment == nullptr) return;  // This should not happen.
+  if (environment == nullptr)
+    return Array::New(isolate);  // This should not happen.
   WCHAR* p = environment;
   while (*p) {
     WCHAR* s;
@@ -198,7 +170,7 @@ static void EnvEnumerator(const PropertyCallbackInfo<Array>& info) {
     if (rc.IsEmpty()) {
       isolate->ThrowException(ERR_STRING_TOO_LONG(isolate));
       FreeEnvironmentStringsW(environment);
-      return;
+      return Local<Array>();
     }
     env_v.push_back(rc.ToLocalChecked());
     p = s + wcslen(s) + 1;
@@ -206,8 +178,80 @@ static void EnvEnumerator(const PropertyCallbackInfo<Array>& info) {
   FreeEnvironmentStringsW(environment);
 #endif
 
-  envarr = Array::New(isolate, env_v.data(), env_v.size());
-  info.GetReturnValue().Set(envarr);
+  return Array::New(isolate, env_v.data(), env_v.size());
+}
+
+static void EnvGetter(Local<Name> property,
+                      const PropertyCallbackInfo<Value>& info) {
+  Environment* env = Environment::GetCurrent(info);
+  if (property->IsSymbol()) {
+    return info.GetReturnValue().SetUndefined();
+  }
+  CHECK(property->IsString());
+  info.GetReturnValue().Set(
+      env->envvars()->Get(env->isolate(), property.As<String>()));
+}
+
+static void EnvSetter(Local<Name> property,
+                      Local<Value> value,
+                      const PropertyCallbackInfo<Value>& info) {
+  Environment* env = Environment::GetCurrent(info);
+  // calling env->EmitProcessEnvWarning() sets a variable indicating that
+  // warnings have been emitted. It should be called last after other
+  // conditions leading to a warning have been met.
+  if (env->options()->pending_deprecation && !value->IsString() &&
+      !value->IsNumber() && !value->IsBoolean() &&
+      env->EmitProcessEnvWarning()) {
+    if (ProcessEmitDeprecationWarning(
+            env,
+            "Assigning any value other than a string, number, or boolean to a "
+            "process.env property is deprecated. Please make sure to convert "
+            "the "
+            "value to a string before setting process.env with it.",
+            "DEP0104")
+            .IsNothing())
+      return;
+  }
+
+  Local<String> key;
+  Local<String> value_string;
+  if (!property->ToString(env->context()).ToLocal(&key) ||
+      !value->ToString(env->context()).ToLocal(&value_string)) {
+    return;
+  }
+
+  env->envvars()->Set(env->isolate(), key, value_string);
+
+  // Whether it worked or not, always return value.
+  info.GetReturnValue().Set(value);
+}
+
+static void EnvQuery(Local<Name> property,
+                     const PropertyCallbackInfo<Integer>& info) {
+  Environment* env = Environment::GetCurrent(info);
+  if (property->IsString()) {
+    int32_t rc = env->envvars()->Query(env->isolate(), property.As<String>());
+    if (rc != -1) info.GetReturnValue().Set(rc);
+  }
+}
+
+static void EnvDeleter(Local<Name> property,
+                       const PropertyCallbackInfo<Boolean>& info) {
+  Environment* env = Environment::GetCurrent(info);
+  if (property->IsString()) {
+    env->envvars()->Delete(env->isolate(), property.As<String>());
+  }
+
+  // process.env never has non-configurable properties, so always
+  // return true like the tc39 delete operator.
+  info.GetReturnValue().Set(true);
+}
+
+static void EnvEnumerator(const PropertyCallbackInfo<Array>& info) {
+  Environment* env = Environment::GetCurrent(info);
+
+  info.GetReturnValue().Set(
+      env->envvars()->Enumerate(env->isolate()));
 }
 
 MaybeLocal<Object> CreateEnvVarProxy(Local<Context> context,
diff --git a/src/node_internals.h b/src/node_internals.h
index 8c2864aae8..012848491e 100644
--- a/src/node_internals.h
+++ b/src/node_internals.h
@@ -293,7 +293,7 @@ int ThreadPoolWork::CancelWork() {
 #endif  // __POSIX__ && !defined(__ANDROID__) && !defined(__CloudABI__)
 
 namespace credentials {
-bool SafeGetenv(const char* key, std::string* text);
+bool SafeGetenv(const char* key, std::string* text, Environment* env = nullptr);
 }  // namespace credentials
 
 void DefineZlibConstants(v8::Local<v8::Object> target);