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-rw-r--r--js/src/vm/Compartment.cpp616
1 files changed, 616 insertions, 0 deletions
diff --git a/js/src/vm/Compartment.cpp b/js/src/vm/Compartment.cpp
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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
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "vm/Compartment-inl.h"
+
+#include "mozilla/MemoryReporting.h"
+
+#include <stddef.h>
+
+#include "jsfriendapi.h"
+
+#include "debugger/DebugAPI.h"
+#include "gc/GC.h"
+#include "gc/Memory.h"
+#include "gc/PublicIterators.h"
+#include "gc/Zone.h"
+#include "js/friend/StackLimits.h" // js::AutoCheckRecursionLimit
+#include "js/friend/WindowProxy.h" // js::IsWindow, js::IsWindowProxy, js::ToWindowProxyIfWindow
+#include "js/Proxy.h"
+#include "js/RootingAPI.h"
+#include "js/StableStringChars.h"
+#include "js/Wrapper.h"
+#include "js/WrapperCallbacks.h"
+#include "proxy/DeadObjectProxy.h"
+#include "proxy/DOMProxy.h"
+#include "vm/JSContext.h"
+#ifdef ENABLE_RECORD_TUPLE
+# include "vm/RecordTupleShared.h"
+#endif
+#include "vm/WrapperObject.h"
+
+#include "gc/Marking-inl.h"
+#include "gc/WeakMap-inl.h"
+#include "vm/JSObject-inl.h"
+#include "vm/Realm-inl.h"
+
+using namespace js;
+
+using JS::AutoStableStringChars;
+
+Compartment::Compartment(Zone* zone, bool invisibleToDebugger)
+ : zone_(zone),
+ runtime_(zone->runtimeFromAnyThread()),
+ invisibleToDebugger_(invisibleToDebugger),
+ crossCompartmentObjectWrappers(zone, 0),
+ realms_(zone) {}
+
+#ifdef JSGC_HASH_TABLE_CHECKS
+
+void Compartment::checkObjectWrappersAfterMovingGC() {
+ for (ObjectWrapperEnum e(this); !e.empty(); e.popFront()) {
+ // Assert that the postbarriers have worked and that nothing is left in the
+ // wrapper map that points into the nursery, and that the hash table entries
+ // are discoverable.
+ auto key = e.front().key();
+ CheckGCThingAfterMovingGC(key.get());
+
+ auto ptr = crossCompartmentObjectWrappers.lookup(key);
+ MOZ_RELEASE_ASSERT(ptr.found() && &*ptr == &e.front());
+ }
+}
+
+#endif // JSGC_HASH_TABLE_CHECKS
+
+bool Compartment::putWrapper(JSContext* cx, JSObject* wrapped,
+ JSObject* wrapper) {
+ MOZ_ASSERT(!js::IsProxy(wrapper) || js::GetProxyHandler(wrapper)->family() !=
+ js::GetDOMRemoteProxyHandlerFamily());
+
+ if (!crossCompartmentObjectWrappers.put(wrapped, wrapper)) {
+ ReportOutOfMemory(cx);
+ return false;
+ }
+
+ return true;
+}
+
+bool Compartment::putWrapper(JSContext* cx, JSString* wrapped,
+ JSString* wrapper) {
+ if (!zone()->crossZoneStringWrappers().put(wrapped, wrapper)) {
+ ReportOutOfMemory(cx);
+ return false;
+ }
+
+ return true;
+}
+
+void Compartment::removeWrapper(js::ObjectWrapperMap::Ptr p) {
+ JSObject* key = p->key();
+ JSObject* value = p->value().unbarrieredGet();
+ if (js::gc::detail::GetDelegate(value) == key) {
+ key->zone()->beforeClearDelegate(value, key);
+ }
+
+ crossCompartmentObjectWrappers.remove(p);
+}
+
+JSString* js::CopyStringPure(JSContext* cx, JSString* str) {
+ /*
+ * Directly allocate the copy in the destination compartment, rather than
+ * first flattening it (and possibly allocating in source compartment),
+ * because we don't know whether the flattening will pay off later.
+ */
+
+ size_t len = str->length();
+ JSString* copy;
+ if (str->isLinear()) {
+ /* Only use AutoStableStringChars if the NoGC allocation fails. */
+ if (str->hasLatin1Chars()) {
+ JS::AutoCheckCannotGC nogc;
+ copy = NewStringCopyN<NoGC>(cx, str->asLinear().latin1Chars(nogc), len);
+ } else {
+ JS::AutoCheckCannotGC nogc;
+ copy = NewStringCopyNDontDeflate<NoGC>(
+ cx, str->asLinear().twoByteChars(nogc), len);
+ }
+ if (copy) {
+ return copy;
+ }
+
+ AutoStableStringChars chars(cx);
+ if (!chars.init(cx, str)) {
+ return nullptr;
+ }
+
+ return chars.isLatin1() ? NewStringCopyN<CanGC>(
+ cx, chars.latin1Range().begin().get(), len)
+ : NewStringCopyNDontDeflate<CanGC>(
+ cx, chars.twoByteRange().begin().get(), len);
+ }
+
+ if (str->hasLatin1Chars()) {
+ UniquePtr<Latin1Char[], JS::FreePolicy> copiedChars =
+ str->asRope().copyLatin1Chars(cx, js::StringBufferArena);
+ if (!copiedChars) {
+ return nullptr;
+ }
+
+ return NewString<CanGC>(cx, std::move(copiedChars), len);
+ }
+
+ UniqueTwoByteChars copiedChars =
+ str->asRope().copyTwoByteChars(cx, js::StringBufferArena);
+ if (!copiedChars) {
+ return nullptr;
+ }
+
+ return NewStringDontDeflate<CanGC>(cx, std::move(copiedChars), len);
+}
+
+bool Compartment::wrap(JSContext* cx, MutableHandleString strp) {
+ MOZ_ASSERT(cx->compartment() == this);
+
+ /* If the string is already in this compartment, we are done. */
+ JSString* str = strp;
+ if (str->zoneFromAnyThread() == zone()) {
+ return true;
+ }
+
+ /*
+ * If the string is an atom, we don't have to copy, but we do need to mark
+ * the atom as being in use by the new zone.
+ */
+ if (str->isAtom()) {
+ cx->markAtom(&str->asAtom());
+ return true;
+ }
+
+ /* Check the cache. */
+ if (StringWrapperMap::Ptr p = lookupWrapper(str)) {
+ strp.set(p->value().get());
+ return true;
+ }
+
+ /* No dice. Make a copy, and cache it. */
+ JSString* copy = CopyStringPure(cx, str);
+ if (!copy) {
+ return false;
+ }
+ if (!putWrapper(cx, strp, copy)) {
+ return false;
+ }
+
+ strp.set(copy);
+ return true;
+}
+
+bool Compartment::wrap(JSContext* cx, MutableHandleBigInt bi) {
+ MOZ_ASSERT(cx->compartment() == this);
+
+ if (bi->zone() == cx->zone()) {
+ return true;
+ }
+
+ BigInt* copy = BigInt::copy(cx, bi);
+ if (!copy) {
+ return false;
+ }
+ bi.set(copy);
+ return true;
+}
+
+bool Compartment::getNonWrapperObjectForCurrentCompartment(
+ JSContext* cx, HandleObject origObj, MutableHandleObject obj) {
+ // Ensure that we have entered a realm.
+ MOZ_ASSERT(cx->global());
+
+ // The object is already in the right compartment. Normally same-
+ // compartment returns the object itself, however, windows are always
+ // wrapped by a proxy, so we have to check for that case here manually.
+ if (obj->compartment() == this) {
+ obj.set(ToWindowProxyIfWindow(obj));
+ return true;
+ }
+
+ // Note that if the object is same-compartment, but has been wrapped into a
+ // different compartment, we need to unwrap it and return the bare same-
+ // compartment object. Note again that windows are always wrapped by a
+ // WindowProxy even when same-compartment so take care not to strip this
+ // particular wrapper.
+ RootedObject objectPassedToWrap(cx, obj);
+ obj.set(UncheckedUnwrap(obj, /* stopAtWindowProxy = */ true));
+ if (obj->compartment() == this) {
+ MOZ_ASSERT(!IsWindow(obj));
+ return true;
+ }
+
+ // Disallow creating new wrappers if we nuked the object's realm or the
+ // current compartment.
+ if (!AllowNewWrapper(this, obj)) {
+ obj.set(NewDeadProxyObject(cx, obj));
+ return !!obj;
+ }
+
+ // Use the WindowProxy instead of the Window here, so that we don't have to
+ // deal with this in the rest of the wrapping code.
+ if (IsWindow(obj)) {
+ obj.set(ToWindowProxyIfWindow(obj));
+
+ // ToWindowProxyIfWindow can return a CCW if |obj| was a navigated-away-from
+ // Window. Strip any CCWs.
+ obj.set(UncheckedUnwrap(obj));
+
+ if (JS_IsDeadWrapper(obj)) {
+ obj.set(NewDeadProxyObject(cx, obj));
+ return !!obj;
+ }
+
+ MOZ_ASSERT(IsWindowProxy(obj) || IsDOMRemoteProxyObject(obj));
+
+ // We crossed a compartment boundary there, so may now have a gray object.
+ // This function is not allowed to return gray objects, so don't do that.
+ ExposeObjectToActiveJS(obj);
+ }
+
+ // If the object is a dead wrapper, return a new dead wrapper rather than
+ // trying to wrap it for a different compartment.
+ if (JS_IsDeadWrapper(obj)) {
+ obj.set(NewDeadProxyObject(cx, obj));
+ return !!obj;
+ }
+
+ // Invoke the prewrap callback. The prewrap callback is responsible for
+ // doing similar reification as above, but can account for any additional
+ // embedder requirements.
+ //
+ // We're a bit worried about infinite recursion here, so we do a check -
+ // see bug 809295.
+ auto preWrap = cx->runtime()->wrapObjectCallbacks->preWrap;
+ AutoCheckRecursionLimit recursion(cx);
+ if (!recursion.checkSystem(cx)) {
+ return false;
+ }
+ if (preWrap) {
+ preWrap(cx, cx->global(), origObj, obj, objectPassedToWrap, obj);
+ if (!obj) {
+ return false;
+ }
+ }
+ MOZ_ASSERT(!IsWindow(obj));
+
+ return true;
+}
+
+bool Compartment::getOrCreateWrapper(JSContext* cx, HandleObject existing,
+ MutableHandleObject obj) {
+ // ScriptSourceObject is an internal object that we never need to wrap.
+ MOZ_ASSERT(!obj->is<ScriptSourceObject>());
+
+ // If we already have a wrapper for this value, use it.
+ if (ObjectWrapperMap::Ptr p = lookupWrapper(obj)) {
+ obj.set(p->value().get());
+ MOZ_ASSERT(obj->is<CrossCompartmentWrapperObject>());
+ return true;
+ }
+
+ // Ensure that the wrappee is exposed in case we are creating a new wrapper
+ // for a gray object.
+ ExposeObjectToActiveJS(obj);
+
+ // Create a new wrapper for the object.
+ auto wrap = cx->runtime()->wrapObjectCallbacks->wrap;
+ RootedObject wrapper(cx, wrap(cx, existing, obj));
+ if (!wrapper) {
+ return false;
+ }
+
+ // We maintain the invariant that the key in the cross-compartment wrapper
+ // map is always directly wrapped by the value.
+ MOZ_ASSERT(Wrapper::wrappedObject(wrapper) == obj);
+
+ if (!putWrapper(cx, obj, wrapper)) {
+ // Enforce the invariant that all cross-compartment wrapper object are
+ // in the map by nuking the wrapper if we couldn't add it.
+ // Unfortunately it's possible for the wrapper to still be marked if we
+ // took this path, for example if the object metadata callback stashes a
+ // reference to it.
+ if (wrapper->is<CrossCompartmentWrapperObject>()) {
+ NukeCrossCompartmentWrapper(cx, wrapper);
+ }
+ return false;
+ }
+
+ obj.set(wrapper);
+ return true;
+}
+
+#ifdef ENABLE_RECORD_TUPLE
+bool Compartment::wrapExtendedPrimitive(JSContext* cx,
+ MutableHandleObject obj) {
+ MOZ_ASSERT(IsExtendedPrimitive(*obj));
+ MOZ_ASSERT(cx->compartment() == this);
+
+ if (obj->compartment() == this) {
+ return true;
+ }
+
+ JSObject* copy = CopyExtendedPrimitive(cx, obj);
+ if (!copy) {
+ return false;
+ }
+
+ obj.set(copy);
+ return true;
+}
+#endif
+
+bool Compartment::wrap(JSContext* cx, MutableHandleObject obj) {
+ MOZ_ASSERT(cx->compartment() == this);
+
+ if (!obj) {
+ return true;
+ }
+
+#ifdef ENABLE_RECORD_TUPLE
+ MOZ_ASSERT(!IsExtendedPrimitive(*obj));
+#endif
+
+ AutoDisableProxyCheck adpc;
+
+ // Anything we're wrapping has already escaped into script, so must have
+ // been unmarked-gray at some point in the past.
+ JS::AssertObjectIsNotGray(obj);
+
+ // The passed object may already be wrapped, or may fit a number of special
+ // cases that we need to check for and manually correct.
+ if (!getNonWrapperObjectForCurrentCompartment(cx, /* origObj = */ nullptr,
+ obj)) {
+ return false;
+ }
+
+ // If the reification above did not result in a same-compartment object,
+ // get or create a new wrapper object in this compartment for it.
+ if (obj->compartment() != this) {
+ if (!getOrCreateWrapper(cx, nullptr, obj)) {
+ return false;
+ }
+ }
+
+ // Ensure that the wrapper is also exposed.
+ ExposeObjectToActiveJS(obj);
+ return true;
+}
+
+bool Compartment::rewrap(JSContext* cx, MutableHandleObject obj,
+ HandleObject existingArg) {
+ MOZ_ASSERT(cx->compartment() == this);
+ MOZ_ASSERT(obj);
+ MOZ_ASSERT(existingArg);
+ MOZ_ASSERT(existingArg->compartment() == cx->compartment());
+ MOZ_ASSERT(IsDeadProxyObject(existingArg));
+
+ AutoDisableProxyCheck adpc;
+
+ // It may not be possible to re-use existing; if so, clear it so that we
+ // are forced to create a new wrapper. Note that this cannot call out to
+ // |wrap| because of the different gray unmarking semantics.
+ RootedObject existing(cx, existingArg);
+ if (existing->hasStaticPrototype() ||
+ // Note: Class asserted above, so all that's left to check is callability
+ existing->isCallable() || obj->isCallable()) {
+ existing.set(nullptr);
+ }
+
+ // The passed object may already be wrapped, or may fit a number of special
+ // cases that we need to check for and manually correct. We pass in
+ // |existingArg| instead of |existing|, because the purpose is to get the
+ // address of the object we are transplanting onto, not to find a wrapper
+ // to reuse.
+ if (!getNonWrapperObjectForCurrentCompartment(cx, existingArg, obj)) {
+ return false;
+ }
+
+ // If the reification above resulted in a same-compartment object, we do
+ // not need to create or return an existing wrapper.
+ if (obj->compartment() == this) {
+ return true;
+ }
+
+ return getOrCreateWrapper(cx, existing, obj);
+}
+
+bool Compartment::wrap(JSContext* cx,
+ MutableHandle<JS::PropertyDescriptor> desc) {
+ if (desc.hasGetter()) {
+ if (!wrap(cx, desc.getter())) {
+ return false;
+ }
+ }
+ if (desc.hasSetter()) {
+ if (!wrap(cx, desc.setter())) {
+ return false;
+ }
+ }
+ if (desc.hasValue()) {
+ if (!wrap(cx, desc.value())) {
+ return false;
+ }
+ }
+ return true;
+}
+
+bool Compartment::wrap(JSContext* cx,
+ MutableHandle<mozilla::Maybe<PropertyDescriptor>> desc) {
+ if (desc.isNothing()) {
+ return true;
+ }
+
+ Rooted<PropertyDescriptor> desc_(cx, *desc);
+ if (!wrap(cx, &desc_)) {
+ return false;
+ }
+ desc.set(mozilla::Some(desc_.get()));
+ return true;
+}
+
+bool Compartment::wrap(JSContext* cx, MutableHandle<GCVector<Value>> vec) {
+ for (size_t i = 0; i < vec.length(); ++i) {
+ if (!wrap(cx, vec[i])) {
+ return false;
+ }
+ }
+ return true;
+}
+
+static inline bool ShouldTraceWrapper(JSObject* wrapper,
+ Compartment::EdgeSelector whichEdges) {
+ if (whichEdges == Compartment::AllEdges) {
+ return true;
+ }
+
+ bool isGray = wrapper->isMarkedGray();
+ return (whichEdges == Compartment::NonGrayEdges && !isGray) ||
+ (whichEdges == Compartment::GrayEdges && isGray);
+}
+
+void Compartment::traceWrapperTargetsInCollectedZones(JSTracer* trc,
+ EdgeSelector whichEdges) {
+ // Trace cross compartment wrapper private pointers into collected zones to
+ // either mark or update them. Wrapped object pointers are updated by
+ // sweepCrossCompartmentObjectWrappers().
+
+ MOZ_ASSERT(JS::RuntimeHeapIsMajorCollecting());
+ MOZ_ASSERT(!zone()->isCollectingFromAnyThread() ||
+ trc->runtime()->gc.isHeapCompacting());
+
+ for (WrappedObjectCompartmentEnum c(this); !c.empty(); c.popFront()) {
+ Zone* zone = c.front()->zone();
+ if (!zone->isCollectingFromAnyThread()) {
+ continue;
+ }
+
+ for (ObjectWrapperEnum e(this, c); !e.empty(); e.popFront()) {
+ JSObject* obj = e.front().value().unbarrieredGet();
+ ProxyObject* wrapper = &obj->as<ProxyObject>();
+ if (ShouldTraceWrapper(wrapper, whichEdges)) {
+ ProxyObject::traceEdgeToTarget(trc, wrapper);
+ }
+ }
+ }
+}
+
+/* static */
+void Compartment::traceIncomingCrossCompartmentEdgesForZoneGC(
+ JSTracer* trc, EdgeSelector whichEdges) {
+ MOZ_ASSERT(JS::RuntimeHeapIsMajorCollecting());
+
+ for (ZonesIter zone(trc->runtime(), SkipAtoms); !zone.done(); zone.next()) {
+ if (zone->isCollectingFromAnyThread()) {
+ continue;
+ }
+
+ for (CompartmentsInZoneIter c(zone); !c.done(); c.next()) {
+ c->traceWrapperTargetsInCollectedZones(trc, whichEdges);
+ }
+ }
+
+ // Currently we trace all debugger edges as black.
+ if (whichEdges != GrayEdges) {
+ DebugAPI::traceCrossCompartmentEdges(trc);
+ }
+}
+
+void Compartment::sweepAfterMinorGC(JSTracer* trc) {
+ crossCompartmentObjectWrappers.sweepAfterMinorGC(trc);
+
+ for (RealmsInCompartmentIter r(this); !r.done(); r.next()) {
+ r->sweepAfterMinorGC(trc);
+ }
+}
+
+// Remove dead wrappers from the table or update pointers to moved objects.
+void Compartment::traceCrossCompartmentObjectWrapperEdges(JSTracer* trc) {
+ crossCompartmentObjectWrappers.traceWeak(trc);
+}
+
+void Compartment::fixupCrossCompartmentObjectWrappersAfterMovingGC(
+ JSTracer* trc) {
+ MOZ_ASSERT(trc->runtime()->gc.isHeapCompacting());
+
+ // Sweep the wrapper map to update keys (wrapped values) in other
+ // compartments that may have been moved.
+ traceCrossCompartmentObjectWrapperEdges(trc);
+
+ // Trace the wrappers in the map to update their cross-compartment edges
+ // to wrapped values in other compartments that may have been moved.
+ traceWrapperTargetsInCollectedZones(trc, AllEdges);
+}
+
+void Compartment::fixupAfterMovingGC(JSTracer* trc) {
+ MOZ_ASSERT(zone()->isGCCompacting());
+
+ for (RealmsInCompartmentIter r(this); !r.done(); r.next()) {
+ r->fixupAfterMovingGC(trc);
+ }
+
+ // Sweep the wrapper map to update values (wrapper objects) in this
+ // compartment that may have been moved.
+ traceCrossCompartmentObjectWrapperEdges(trc);
+}
+
+void Compartment::addSizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf,
+ size_t* compartmentObjects,
+ size_t* crossCompartmentWrappersTables,
+ size_t* compartmentsPrivateData) {
+ *compartmentObjects += mallocSizeOf(this);
+ *crossCompartmentWrappersTables +=
+ crossCompartmentObjectWrappers.sizeOfExcludingThis(mallocSizeOf);
+
+ if (auto callback = runtime_->sizeOfIncludingThisCompartmentCallback) {
+ *compartmentsPrivateData += callback(mallocSizeOf, this);
+ }
+}
+
+GlobalObject& Compartment::firstGlobal() const {
+ for (Realm* realm : realms_) {
+ if (!realm->hasInitializedGlobal()) {
+ continue;
+ }
+ GlobalObject* global = realm->maybeGlobal();
+ ExposeObjectToActiveJS(global);
+ return *global;
+ }
+ MOZ_CRASH("If all our globals are dead, why is someone expecting a global?");
+}
+
+JS_PUBLIC_API JSObject* js::GetFirstGlobalInCompartment(JS::Compartment* comp) {
+ return &comp->firstGlobal();
+}
+
+JS_PUBLIC_API bool js::CompartmentHasLiveGlobal(JS::Compartment* comp) {
+ MOZ_ASSERT(comp);
+ for (Realm* r : comp->realms()) {
+ if (r->hasLiveGlobal()) {
+ return true;
+ }
+ }
+ return false;
+}
+
+void Compartment::traceWeakNativeIterators(JSTracer* trc) {
+ /* Sweep list of native iterators. */
+ NativeIteratorListIter iter(&enumerators_);
+ while (!iter.done()) {
+ NativeIterator* ni = iter.next();
+ JSObject* iterObj = ni->iterObj();
+ if (!TraceManuallyBarrieredWeakEdge(trc, &iterObj,
+ "Compartment::enumerators_")) {
+ ni->unlink();
+ }
+ MOZ_ASSERT(ni->objectBeingIterated()->compartment() == this);
+ }
+}