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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=8 sts=2 et sw=2 tw=80:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "builtin/ShadowRealm.h"
#include "mozilla/Assertions.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "builtin/ModuleObject.h"
#include "builtin/Promise.h"
#include "builtin/WrappedFunctionObject.h"
#include "frontend/BytecodeCompiler.h" // CompileEvalScript
#include "js/ErrorReport.h"
#include "js/Exception.h"
#include "js/GlobalObject.h"
#include "js/Principals.h"
#include "js/Promise.h"
#include "js/PropertyAndElement.h"
#include "js/PropertyDescriptor.h"
#include "js/ShadowRealmCallbacks.h"
#include "js/SourceText.h"
#include "js/StableStringChars.h"
#include "js/StructuredClone.h"
#include "js/TypeDecls.h"
#include "js/Wrapper.h"
#include "vm/GlobalObject.h"
#include "vm/Interpreter.h"
#include "vm/JSObject.h"
#include "vm/ObjectOperations.h"
#include "builtin/HandlerFunction-inl.h"
#include "vm/Compartment-inl.h"
#include "vm/JSObject-inl.h"
#include "vm/Realm-inl.h"
using namespace js;
using JS::AutoStableStringChars;
using JS::CompileOptions;
using JS::SourceOwnership;
using JS::SourceText;
static JSObject* DefaultNewShadowRealmGlobal(JSContext* cx,
JS::RealmOptions& options,
JSPrincipals* principals,
Handle<JSObject*> unused) {
static const JSClass shadowRealmGlobal = {
"ShadowRealmGlobal", JSCLASS_GLOBAL_FLAGS, &JS::DefaultGlobalClassOps};
return JS_NewGlobalObject(cx, &shadowRealmGlobal, principals,
JS::FireOnNewGlobalHook, options);
}
/*static*/
bool ShadowRealmObject::construct(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// Step 1. If NewTarget is undefined, throw a TypeError exception.
if (!args.isConstructing()) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_NOT_CONSTRUCTOR, "ShadowRealm");
return false;
}
// Step 2. Let O be ? OrdinaryCreateFromConstructor(NewTarget,
// "%ShadowRealm.prototype%", « [[ShadowRealm]], [[ExecutionContext]] »).
Rooted<JSObject*> proto(cx);
if (!GetPrototypeFromBuiltinConstructor(cx, args, JSProto_ShadowRealm,
&proto)) {
return false;
}
Rooted<ShadowRealmObject*> shadowRealmObj(
cx, NewObjectWithClassProto<ShadowRealmObject>(cx, proto));
if (!shadowRealmObj) {
return false;
}
// Instead of managing Realms, spidermonkey associates a realm with a global
// object, and so we will manage and store a global.
// Step 3. Let realmRec be CreateRealm().
// Initially steal creation options from current realm:
JS::RealmOptions options(cx->realm()->creationOptions(),
cx->realm()->behaviors());
// We don't want to have to deal with CCWs in addition to
// WrappedFunctionObjects.
options.creationOptions().setExistingCompartment(cx->compartment());
JS::GlobalCreationCallback newGlobal =
cx->runtime()->getShadowRealmGlobalCreationCallback();
// If an embedding didn't provide a callback to initialize the global,
// use the basic default one.
if (!newGlobal) {
newGlobal = DefaultNewShadowRealmGlobal;
}
// Our shadow realm inherits the principals of the current realm,
// but is otherwise constrained.
JSPrincipals* principals = JS::GetRealmPrincipals(cx->realm());
// Steps 5-11: In SpiderMonkey these fall under the aegis of the global
// creation. It's worth noting that the newGlobal callback
// needs to respect the SetRealmGlobalObject call below, which
// sets the global to
// OrdinaryObjectCreate(intrinsics.[[%Object.prototype%]]).
//
// Step 5. Let context be a new execution context.
// Step 6. Set the Function of context to null.
// Step 7. Set the Realm of context to realmRec.
// Step 8. Set the ScriptOrModule of context to null.
// Step 9. Set O.[[ExecutionContext]] to context.
// Step 10. Perform ? SetRealmGlobalObject(realmRec, undefined, undefined).
// Step 11. Perform ? SetDefaultGlobalBindings(O.[[ShadowRealm]]).
Rooted<JSObject*> global(cx,
newGlobal(cx, options, principals, cx->global()));
if (!global) {
return false;
}
// Make sure the new global hook obeyed our request in the
// creation options to have a same compartment global.
MOZ_RELEASE_ASSERT(global->compartment() == cx->compartment());
// Step 4. Set O.[[ShadowRealm]] to realmRec.
shadowRealmObj->initFixedSlot(GlobalSlot, ObjectValue(*global));
// Step 12. Perform ? HostInitializeShadowRealm(O.[[ShadowRealm]]).
JS::GlobalInitializeCallback hostInitializeShadowRealm =
cx->runtime()->getShadowRealmInitializeGlobalCallback();
if (hostInitializeShadowRealm) {
if (!hostInitializeShadowRealm(cx, global)) {
return false;
}
}
// Step 13. Return O.
args.rval().setObject(*shadowRealmObj);
return true;
}
// (slightly modified into a cast operator too)
static ShadowRealmObject* ValidateShadowRealmObject(JSContext* cx,
Handle<Value> value) {
// Step 1. Perform ? RequireInternalSlot(O, [[ShadowRealm]]).
// Step 2. Perform ? RequireInternalSlot(O, [[ExecutionContext]]).
return UnwrapAndTypeCheckValue<ShadowRealmObject>(cx, value, [cx]() {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_NOT_SHADOW_REALM);
});
}
void js::ReportPotentiallyDetailedMessage(JSContext* cx,
const unsigned detailedError,
const unsigned genericError) {
// Return for non-catchable exceptions like interrupt requests.
if (!cx->isExceptionPending()) {
return;
}
Rooted<Value> exception(cx);
if (!cx->getPendingException(&exception)) {
return;
}
cx->clearPendingException();
JS::ErrorReportBuilder jsReport(cx);
JS::ExceptionStack exnStack(cx, exception, nullptr);
if (!jsReport.init(cx, exnStack, JS::ErrorReportBuilder::NoSideEffects)) {
cx->clearPendingException();
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, genericError);
return;
}
JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, detailedError,
jsReport.toStringResult().c_str());
}
// PerformShadowRealmEval ( sourceText: a String, callerRealm: a Realm Record,
// evalRealm: a Realm Record, )
//
static bool PerformShadowRealmEval(JSContext* cx, Handle<JSString*> sourceText,
Realm* callerRealm, Realm* evalRealm,
MutableHandle<Value> rval) {
MOZ_ASSERT(callerRealm != evalRealm);
// Step 1. Perform ? HostEnsureCanCompileStrings(callerRealm, evalRealm).
if (!cx->isRuntimeCodeGenEnabled(JS::RuntimeCode::JS, sourceText)) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_CSP_BLOCKED_SHADOWREALM);
return false;
}
// Need to compile the script into the realm we will execute into.
//
// We hoist the error handling out however to ensure that errors
// are thrown from the correct realm.
bool compileSuccess = false;
bool evalSuccess = false;
do {
Rooted<GlobalObject*> evalRealmGlobal(cx, evalRealm->maybeGlobal());
AutoRealm ar(cx, evalRealmGlobal);
// Step 2. Perform the following substeps in an implementation-defined
// order, possibly interleaving parsing and error detection:
// a. Let script be ParseText(! StringToCodePoints(sourceText), Script).
// b. If script is a List of errors, throw a SyntaxError exception.
// c. If script Contains ScriptBody is false, return undefined.
// d. Let body be the ScriptBody of script.
// e. If body Contains NewTarget is true, throw a SyntaxError exception.
// f. If body Contains SuperProperty is true, throw a SyntaxError
// exception. g. If body Contains SuperCall is true, throw a SyntaxError
// exception.
AutoStableStringChars linearChars(cx);
if (!linearChars.initTwoByte(cx, sourceText)) {
return false;
}
SourceText<char16_t> srcBuf;
if (!srcBuf.initMaybeBorrowed(cx, linearChars)) {
return false;
}
// Lets propagate some information into the compilation here.
//
// We may need to censor the stacks eventually, see
RootedScript callerScript(cx);
const char* filename;
uint32_t lineno;
uint32_t pcOffset;
bool mutedErrors;
DescribeScriptedCallerForCompilation(cx, &callerScript, &filename, &lineno,
&pcOffset, &mutedErrors);
CompileOptions options(cx);
options.setIsRunOnce(true)
.setNoScriptRval(false)
.setMutedErrors(mutedErrors)
.setFileAndLine(filename, lineno);
Rooted<Scope*> enclosing(cx, &evalRealmGlobal->emptyGlobalScope());
RootedScript script(
cx, frontend::CompileEvalScript(cx, options, srcBuf, enclosing,
evalRealmGlobal));
compileSuccess = !!script;
if (!compileSuccess) {
break;
}
// Step 3. Let strictEval be IsStrict of script.
// Step 4. Let runningContext be the running execution context.
// Step 5. Let lexEnv be NewDeclarativeEnvironment(evalRealm.[[GlobalEnv]]).
// Step 6. Let varEnv be evalRealm.[[GlobalEnv]].
// Step 7. If strictEval is true, set varEnv to lexEnv.
// Step 8. If runningContext is not already suspended, suspend
// runningContext. Step 9. Let evalContext be a new ECMAScript code
// execution context. Step 10. Set evalContext's Function to null. Step 11.
// Set evalContext's Realm to evalRealm. Step 12. Set evalContext's
// ScriptOrModule to null. Step 13. Set evalContext's VariableEnvironment to
// varEnv. Step 14. Set evalContext's LexicalEnvironment to lexEnv. Step 15.
// Push evalContext onto the execution context stack; evalContext is
// now the running execution context.
// Step 16. Let result be EvalDeclarationInstantiation(body, varEnv,
// lexEnv, null, strictEval).
// Step 17. If result.[[Type]] is normal, then
// a. Set result to the result of evaluating body.
// Step 18. If result.[[Type]] is normal and result.[[Value]] is empty, then
// a. Set result to NormalCompletion(undefined).
// Step 19. Suspend evalContext and remove it from the execution context
// stack.
// Step 20. Resume the context that is now on the top of the execution
// context stack as the running execution context.
Rooted<JSObject*> environment(cx, &evalRealmGlobal->lexicalEnvironment());
evalSuccess = ExecuteKernel(cx, script, environment,
/* evalInFrame = */ NullFramePtr(), rval);
} while (false); // AutoRealm
if (!compileSuccess) {
if (!cx->isExceptionPending()) {
return false;
}
// Clone the exception into the current global and re-throw, as the
// exception has to come from the current global.
Rooted<Value> exception(cx);
if (!cx->getPendingException(&exception)) {
return false;
}
// Clear our exception now that we've got it, so that we don't
// do the following call with an exception already pending.
cx->clearPendingException();
Rooted<Value> clonedException(cx);
if (!JS_StructuredClone(cx, exception, &clonedException, nullptr,
nullptr)) {
return false;
}
cx->setPendingException(clonedException, ShouldCaptureStack::Always);
return false;
}
if (!evalSuccess) {
// Step 21. If result.[[Type]] is not normal, throw a TypeError
// exception.
//
// The type error here needs to come from the calling global, so has to
// happen outside the AutoRealm above.
ReportPotentiallyDetailedMessage(cx,
JSMSG_SHADOW_REALM_EVALUATE_FAILURE_DETAIL,
JSMSG_SHADOW_REALM_EVALUATE_FAILURE);
return false;
}
// Wrap |rval| into the current compartment.
if (!cx->compartment()->wrap(cx, rval)) {
return false;
}
// Step 22. Return ? GetWrappedValue(callerRealm, result.[[Value]]).
return GetWrappedValue(cx, callerRealm, rval, rval);
}
// ShadowRealm.prototype.evaluate ( sourceText )
static bool ShadowRealm_evaluate(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// Step 1. Let O be this value.
HandleValue obj = args.thisv();
// Step 2. Perform ? ValidateShadowRealmObject(O)
Rooted<ShadowRealmObject*> shadowRealm(cx,
ValidateShadowRealmObject(cx, obj));
if (!shadowRealm) {
return false;
}
// Step 3. If Type(sourceText) is not String, throw a TypeError exception.
if (!args.get(0).isString()) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_SHADOW_REALM_EVALUATE_NOT_STRING);
return false;
}
Rooted<JSString*> sourceText(cx, args.get(0).toString());
// Step 4. Let callerRealm be the current Realm Record.
Realm* callerRealm = cx->realm();
// Step 5. Let evalRealm be O.[[ShadowRealm]].
Realm* evalRealm = shadowRealm->getShadowRealm();
// Step 6. Return ? PerformShadowRealmEval(sourceText, callerRealm,
// evalRealm).
return PerformShadowRealmEval(cx, sourceText, callerRealm, evalRealm,
args.rval());
}
enum class ImportValueIndices : uint32_t {
CalleRealm = 0,
ExportNameString,
Length,
};
// MG:XXX: Cribbed/Overlapping with StartDynamicModuleImport; may need to
// refactor to share.
static JSObject* ShadowRealmImportValue(JSContext* cx,
Handle<JSString*> specifierString,
Handle<JSString*> exportName,
Realm* callerRealm, Realm* evalRealm) {
// Step 1. Assert: evalContext is an execution context associated to a
// ShadowRealm instance's [[ExecutionContext]].
// Step 2. Let innerCapability be ! NewPromiseCapability(%Promise%).
Rooted<JSObject*> promiseConstructor(cx, JS::GetPromiseConstructor(cx));
if (!promiseConstructor) {
return nullptr;
}
Rooted<JSObject*> promiseObject(cx, JS::NewPromiseObject(cx, nullptr));
if (!promiseObject) {
return nullptr;
}
Handle<PromiseObject*> promise = promiseObject.as<PromiseObject>();
JS::ModuleDynamicImportHook importHook =
cx->runtime()->moduleDynamicImportHook;
if (!importHook) {
// Dynamic import can be disabled by a pref and is not supported in all
// contexts (e.g. web workers).
JS_ReportErrorASCII(
cx,
"Dynamic module import is disabled or not supported in this context");
if (!RejectPromiseWithPendingError(cx, promise)) {
return nullptr;
}
return promise;
}
{
// Step 3. Let runningContext be the running execution context. (Implicit)
// Step 4. If runningContext is not already suspended, suspend
// runningContext. (Implicit)
// Step 5. Push evalContext onto the execution context stack; evalContext is
// now the running execution context. (Implicit)
Rooted<GlobalObject*> evalRealmGlobal(cx, evalRealm->maybeGlobal());
AutoRealm ar(cx, evalRealmGlobal);
// Not Speced: Get referencing private to pass to importHook.
RootedScript script(cx);
const char* filename;
uint32_t lineno;
uint32_t pcOffset;
bool mutedErrors;
DescribeScriptedCallerForCompilation(cx, &script, &filename, &lineno,
&pcOffset, &mutedErrors);
MOZ_ASSERT(script);
Rooted<JSAtom*> specifierAtom(cx, AtomizeString(cx, specifierString));
if (!specifierAtom) {
if (!RejectPromiseWithPendingError(cx, promise)) {
return nullptr;
}
return promise;
}
Rooted<ArrayObject*> assertionArray(cx);
Rooted<JSObject*> moduleRequest(
cx, ModuleRequestObject::create(cx, specifierAtom, assertionArray));
if (!moduleRequest) {
if (!RejectPromiseWithPendingError(cx, promise)) {
return nullptr;
}
return promise;
}
// Step 6. Perform ! HostImportModuleDynamically(null, specifierString,
// innerCapability).
//
// By specification, this is supposed to take ReferencingScriptOrModule as
// null, see first parameter above. However, if we do that, we don't end up
// with a script reference, which is used to figure out what the base-URI
// should be So then we end up using the default one for the module loader;
// which because of the way we set the parent module loader up, means we end
// up having the incorrect base URI, as the module loader ends up just using
// the document's base URI.
//
// discuss this.
Rooted<Value> referencingPrivate(cx, script->sourceObject()->getPrivate());
if (!importHook(cx, referencingPrivate, moduleRequest, promise)) {
// If there's no exception pending then the script is terminating
// anyway, so just return nullptr.
if (!cx->isExceptionPending() ||
!RejectPromiseWithPendingError(cx, promise)) {
return nullptr;
}
return promise;
}
// Step 7. Suspend evalContext and remove it from the execution context
// stack. (Implicit)
// Step 8. Resume the context that is now on the top of the execution
// context stack as the running execution context (Implicit)
}
// Step 9. Let steps be the steps of an ExportGetter function as described
// below.
// Step 10. Let onFulfilled be ! CreateBuiltinFunction(steps, 1, "", «
// [[ExportNameString]] », callerRealm).
// The handler can only hold onto a single object, so we pack that into a new
// array, and store there.
Rooted<ArrayObject*> handlerObject(
cx,
NewDenseFullyAllocatedArray(cx, uint32_t(ImportValueIndices::Length)));
if (!handlerObject) {
return nullptr;
}
handlerObject->setDenseInitializedLength(
uint32_t(ImportValueIndices::Length));
handlerObject->initDenseElement(uint32_t(ImportValueIndices::CalleRealm),
PrivateValue(callerRealm));
handlerObject->initDenseElement(
uint32_t(ImportValueIndices::ExportNameString), StringValue(exportName));
Rooted<JSFunction*> onFulfilled(
cx,
NewHandlerWithExtra(
cx,
[](JSContext* cx, unsigned argc, Value* vp) {
// This is the export getter function from
CallArgs args = CallArgsFromVp(argc, vp);
MOZ_ASSERT(args.length() == 1);
auto* handlerObject = ExtraFromHandler<ArrayObject>(args);
Rooted<Value> realmValue(
cx, handlerObject->getDenseElement(
uint32_t(ImportValueIndices::CalleRealm)));
Rooted<Value> exportNameValue(
cx, handlerObject->getDenseElement(
uint32_t(ImportValueIndices::ExportNameString)));
// Step 1. Assert: exports is a module namespace exotic object.
Handle<Value> exportsValue = args[0];
MOZ_ASSERT(exportsValue.isObject() &&
exportsValue.toObject().is<ModuleNamespaceObject>());
Rooted<ModuleNamespaceObject*> exports(
cx, &exportsValue.toObject().as<ModuleNamespaceObject>());
// Step 2. Let f be the active function object. (not implemented
// this way)
//
// Step 3. Let string be f.[[ExportNameString]]. Step 4.
// Assert: Type(string) is String.
MOZ_ASSERT(exportNameValue.isString());
Rooted<JSAtom*> stringAtom(
cx, AtomizeString(cx, exportNameValue.toString()));
if (!stringAtom) {
return false;
}
Rooted<jsid> stringId(cx, AtomToId(stringAtom));
// Step 5. Let hasOwn be ? HasOwnProperty(exports, string).
bool hasOwn = false;
if (!HasOwnProperty(cx, exports, stringId, &hasOwn)) {
return false;
}
// Step 6. If hasOwn is false, throw a TypeError exception.
if (!hasOwn) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_SHADOW_REALM_VALUE_NOT_EXPORTED);
return false;
}
// Step 7. Let value be ? Get(exports, string).
Rooted<Value> value(cx);
if (!GetProperty(cx, exports, exports, stringId, &value)) {
return false;
}
// Step 8. Let realm be f.[[Realm]].
Realm* callerRealm = static_cast<Realm*>(realmValue.toPrivate());
// Step 9. Return ? GetWrappedValue(realm, value).
return GetWrappedValue(cx, callerRealm, value, args.rval());
},
promise, handlerObject));
if (!onFulfilled) {
return nullptr;
}
Rooted<JSFunction*> onRejected(
cx, NewHandler(
cx,
[](JSContext* cx, unsigned argc, Value* vp) {
JS_ReportErrorNumberASCII(
cx, GetErrorMessage, nullptr,
JSMSG_SHADOW_REALM_IMPORTVALUE_FAILED);
return false;
},
promise));
if (!onRejected) {
return nullptr;
}
// Step 11. Set onFulfilled.[[ExportNameString]] to exportNameString.
// Step 12. Let promiseCapability be ! NewPromiseCapability(%Promise%).
// Step 13. Return ! PerformPromiseThen(innerCapability.[[Promise]],
// onFulfilled, callerRealm.[[Intrinsics]].[[%ThrowTypeError%]],
// promiseCapability).
return OriginalPromiseThen(cx, promise, onFulfilled, onRejected);
}
// ShadowRealm.prototype.importValue ( specifier, exportName )
static bool ShadowRealm_importValue(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// Step 1. Let O be this value.
HandleValue obj = args.thisv();
// Step 2. Perform ? ValidateShadowRealmObject(O).
Rooted<ShadowRealmObject*> shadowRealm(cx,
ValidateShadowRealmObject(cx, obj));
if (!shadowRealm) {
return false;
}
// Step 3. Let specifierString be ? ToString(specifier).
Rooted<JSString*> specifierString(cx, ToString<CanGC>(cx, args.get(0)));
if (!specifierString) {
return false;
}
// Step 4. If Type(exportName) is not String, throw a TypeError exception.
if (!args.get(1).isString()) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_SHADOW_REALM_EXPORT_NOT_STRING);
return false;
}
Rooted<JSString*> exportName(cx, args.get(1).toString());
if (!exportName) {
return false;
}
// Step 5. Let callerRealm be the current Realm Record.
Realm* callerRealm = cx->realm();
// Step 6. Let evalRealm be O.[[ShadowRealm]].
Realm* evalRealm = shadowRealm->getShadowRealm();
// Step 7. Let evalContext be O.[[ExecutionContext]]
// (we dont' pass this explicitly, instead using the realm+global to
// represent)
// Step 8. Return ?
// ShadowRealmImportValue(specifierString, exportName,
// callerRealm, evalRealm,
// evalContext).
JSObject* res = ShadowRealmImportValue(cx, specifierString, exportName,
callerRealm, evalRealm);
if (!res) {
return false;
}
args.rval().set(ObjectValue(*res));
return true;
}
static const JSFunctionSpec shadowrealm_methods[] = {
JS_FN("evaluate", ShadowRealm_evaluate, 1, 0),
JS_FN("importValue", ShadowRealm_importValue, 2, 0),
JS_FS_END,
};
static const JSPropertySpec shadowrealm_properties[] = {
JS_STRING_SYM_PS(toStringTag, "ShadowRealm", JSPROP_READONLY),
JS_PS_END,
};
static const ClassSpec ShadowRealmObjectClassSpec = {
GenericCreateConstructor<ShadowRealmObject::construct, 0,
gc::AllocKind::FUNCTION>,
GenericCreatePrototype<ShadowRealmObject>,
nullptr, // Static methods
nullptr, // Static properties
shadowrealm_methods, // Methods
shadowrealm_properties, // Properties
};
const JSClass ShadowRealmObject::class_ = {
"ShadowRealm",
JSCLASS_HAS_CACHED_PROTO(JSProto_ShadowRealm) |
JSCLASS_HAS_RESERVED_SLOTS(ShadowRealmObject::SlotCount),
JS_NULL_CLASS_OPS,
&ShadowRealmObjectClassSpec,
};
const JSClass ShadowRealmObject::protoClass_ = {
"ShadowRealm.prototype",
JSCLASS_HAS_CACHED_PROTO(JSProto_ShadowRealm),
JS_NULL_CLASS_OPS,
&ShadowRealmObjectClassSpec,
};