DXR is a code search and navigation tool aimed at making sense of large projects. It supports full-text and regex searches as well as structural queries.

Mercurial (c68fe15a81fc)

VCS Links

Line Code
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495
/* -*- 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/. */

/* Class used to manage the wrapped native objects within a JS scope. */

#include "AccessCheck.h"
#include "xpcprivate.h"
#include "XPCWrapper.h"
#include "nsContentUtils.h"
#include "nsCycleCollectionNoteRootCallback.h"
#include "ExpandedPrincipal.h"
#include "mozilla/BasePrincipal.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/Preferences.h"
#include "mozilla/Unused.h"
#include "mozJSComponentLoader.h"

#include "mozilla/dom/BindingUtils.h"

using namespace mozilla;
using namespace xpc;
using namespace JS;

/***************************************************************************/

static XPCWrappedNativeScopeList& AllScopes() {
  return XPCJSRuntime::Get()->GetWrappedNativeScopes();
}

static bool RemoteXULForbidsXBLScopeForPrincipal(nsIPrincipal* aPrincipal) {
  // AllowXULXBLForPrincipal will return true for system principal, but we
  // don't want that here.
  MOZ_ASSERT(nsContentUtils::IsInitialized());
  if (aPrincipal->IsSystemPrincipal()) {
    return false;
  }

  // If this domain isn't whitelisted, we're done.
  if (!nsContentUtils::AllowXULXBLForPrincipal(aPrincipal)) {
    return false;
  }

  // Check the pref to determine how we should behave.
  return !Preferences::GetBool("dom.use_xbl_scopes_for_remote_xul", false);
}

static bool RemoteXULForbidsXBLScope(HandleObject aFirstGlobal) {
  MOZ_ASSERT(aFirstGlobal);

  // Certain singleton sandoxes are created very early in startup - too early
  // to call into AllowXULXBLForPrincipal. We never create XBL scopes for
  // sandboxes anway, and certainly not for these singleton scopes. So we just
  // short-circuit here.
  if (IsSandbox(aFirstGlobal)) {
    return false;
  }

  nsIPrincipal* principal = xpc::GetObjectPrincipal(aFirstGlobal);
  return RemoteXULForbidsXBLScopeForPrincipal(principal);
}

XPCWrappedNativeScope::XPCWrappedNativeScope(JS::Compartment* aCompartment,
                                             JS::HandleObject aFirstGlobal)
    : mWrappedNativeMap(mozilla::MakeUnique<Native2WrappedNativeMap>()),
      mWrappedNativeProtoMap(
          mozilla::MakeUnique<ClassInfo2WrappedNativeProtoMap>()),
      mComponents(nullptr),
      mCompartment(aCompartment) {
#ifdef DEBUG
  for (XPCWrappedNativeScope* cur : AllScopes()) {
    MOZ_ASSERT(aCompartment != cur->Compartment(), "dup object");
  }
#endif

  AllScopes().insertBack(this);

  MOZ_COUNT_CTOR(XPCWrappedNativeScope);

  // Determine whether we would allow an XBL scope in this situation.
  // In addition to being pref-controlled, we also disable XBL scopes for
  // remote XUL domains, _except_ if we have an additional pref override set.
  //
  // Note that we can't quite remove this yet, even though we never actually
  // use XBL scopes, because the security manager uses this boolean to make
  // decisions that we rely on in our test infrastructure.
  //
  // FIXME(emilio): Now that the security manager is the only caller probably
  // should be renamed, but what's a good name for this?
  mAllowContentXBLScope = !RemoteXULForbidsXBLScope(aFirstGlobal);
}

bool XPCWrappedNativeScope::GetComponentsJSObject(JSContext* cx,
                                                  JS::MutableHandleObject obj) {
  if (!mComponents) {
    bool system = AccessCheck::isChrome(mCompartment);
    MOZ_RELEASE_ASSERT(system, "How did we get a non-system Components?");
    mComponents = new nsXPCComponents(this);
  }

  RootedValue val(cx);
  xpcObjectHelper helper(mComponents);
  bool ok = XPCConvert::NativeInterface2JSObject(cx, &val, helper, nullptr,
                                                 false, nullptr);
  if (NS_WARN_IF(!ok)) {
    return false;
  }

  if (NS_WARN_IF(!val.isObject())) {
    return false;
  }

  obj.set(&val.toObject());
  return true;
}

static bool DefineSubcomponentProperty(JSContext* aCx, HandleObject aGlobal,
                                       nsISupports* aSubcomponent,
                                       const nsID* aIID,
                                       unsigned int aStringIndex) {
  RootedValue subcompVal(aCx);
  xpcObjectHelper helper(aSubcomponent);
  if (!XPCConvert::NativeInterface2JSObject(aCx, &subcompVal, helper, aIID,
                                            false, nullptr))
    return false;
  if (NS_WARN_IF(!subcompVal.isObject())) {
    return false;
  }
  RootedId id(aCx, XPCJSContext::Get()->GetStringID(aStringIndex));
  return JS_DefinePropertyById(aCx, aGlobal, id, subcompVal, 0);
}

bool XPCWrappedNativeScope::AttachComponentsObject(JSContext* aCx) {
  RootedObject components(aCx);
  if (!GetComponentsJSObject(aCx, &components)) {
    return false;
  }

  RootedObject global(aCx, CurrentGlobalOrNull(aCx));

  const unsigned attrs = JSPROP_READONLY | JSPROP_RESOLVING | JSPROP_PERMANENT;

  RootedId id(aCx,
              XPCJSContext::Get()->GetStringID(XPCJSContext::IDX_COMPONENTS));
  if (!JS_DefinePropertyById(aCx, global, id, components, attrs)) {
    return false;
  }

// _iid can be nullptr if the object implements classinfo.
#define DEFINE_SUBCOMPONENT_PROPERTY(_comp, _type, _iid, _id)                 \
  nsCOMPtr<nsIXPCComponents_##_type> obj##_type;                              \
  if (NS_FAILED(_comp->Get##_type(getter_AddRefs(obj##_type)))) return false; \
  if (!DefineSubcomponentProperty(aCx, global, obj##_type, _iid,              \
                                  XPCJSContext::IDX_##_id))                   \
    return false;

  DEFINE_SUBCOMPONENT_PROPERTY(mComponents, Interfaces, nullptr, CI)
  DEFINE_SUBCOMPONENT_PROPERTY(mComponents, Results, nullptr, CR)

  DEFINE_SUBCOMPONENT_PROPERTY(mComponents, Classes, nullptr, CC)
  DEFINE_SUBCOMPONENT_PROPERTY(mComponents, Utils,
                               &NS_GET_IID(nsIXPCComponents_Utils), CU)

#undef DEFINE_SUBCOMPONENT_PROPERTY

  return true;
}

bool XPCWrappedNativeScope::XBLScopeStateMatches(nsIPrincipal* aPrincipal) {
  return mAllowContentXBLScope ==
         !RemoteXULForbidsXBLScopeForPrincipal(aPrincipal);
}

bool XPCWrappedNativeScope::AllowContentXBLScope(Realm* aRealm) {
  // We only disallow XBL scopes in remote XUL situations.
  MOZ_ASSERT_IF(!mAllowContentXBLScope, nsContentUtils::AllowXULXBLForPrincipal(
                                            xpc::GetRealmPrincipal(aRealm)));
  return mAllowContentXBLScope;
}

namespace xpc {
JSObject* GetUAWidgetScope(JSContext* cx, JSObject* contentScopeArg) {
  JS::RootedObject contentScope(cx, contentScopeArg);
  JSAutoRealm ar(cx, contentScope);
  nsIPrincipal* principal = GetObjectPrincipal(contentScope);

  if (principal->IsSystemPrincipal()) {
    return JS::GetNonCCWObjectGlobal(contentScope);
  }

  return GetUAWidgetScope(cx, principal);
}

JSObject* GetUAWidgetScope(JSContext* cx, nsIPrincipal* principal) {
  RootedObject scope(cx, XPCJSRuntime::Get()->GetUAWidgetScope(cx, principal));
  NS_ENSURE_TRUE(scope, nullptr);  // See bug 858642.

  scope = js::UncheckedUnwrap(scope);
  JS::ExposeObjectToActiveJS(scope);
  return scope;
}

bool AllowContentXBLScope(JS::Realm* realm) {
  JS::Compartment* comp = GetCompartmentForRealm(realm);
  XPCWrappedNativeScope* scope = CompartmentPrivate::Get(comp)->GetScope();
  MOZ_ASSERT(scope);
  return scope->AllowContentXBLScope(realm);
}

} /* namespace xpc */

XPCWrappedNativeScope::~XPCWrappedNativeScope() {
  MOZ_COUNT_DTOR(XPCWrappedNativeScope);

  // We can do additional cleanup assertions here...

  MOZ_ASSERT(0 == mWrappedNativeMap->Count(), "scope has non-empty map");

  MOZ_ASSERT(0 == mWrappedNativeProtoMap->Count(), "scope has non-empty map");

  // This should not be necessary, since the Components object should die
  // with the scope but just in case.
  if (mComponents) {
    mComponents->mScope = nullptr;
  }

  // XXX we should assert that we are dead or that xpconnect has shutdown
  // XXX might not want to do this at xpconnect shutdown time???
  mComponents = nullptr;

  MOZ_RELEASE_ASSERT(!mXrayExpandos.initialized());

  mCompartment = nullptr;
}

// static
void XPCWrappedNativeScope::TraceWrappedNativesInAllScopes(XPCJSRuntime* xpcrt,
                                                           JSTracer* trc) {
  // Do JS::TraceEdge for all wrapped natives with external references, as
  // well as any DOM expando objects.
  //
  // Note: the GC can call this from a JS helper thread. We don't use
  // AllScopes() because that asserts we're on the main thread.

  for (XPCWrappedNativeScope* cur : xpcrt->GetWrappedNativeScopes()) {
    for (auto i = cur->mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
      auto entry = static_cast<Native2WrappedNativeMap::Entry*>(i.Get());
      XPCWrappedNative* wrapper = entry->value;
      if (wrapper->HasExternalReference() && !wrapper->IsWrapperExpired()) {
        wrapper->TraceSelf(trc);
      }
    }
  }
}

// static
void XPCWrappedNativeScope::SuspectAllWrappers(
    nsCycleCollectionNoteRootCallback& cb) {
  for (XPCWrappedNativeScope* cur : AllScopes()) {
    for (auto i = cur->mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
      static_cast<Native2WrappedNativeMap::Entry*>(i.Get())->value->Suspect(cb);
    }
  }
}

void XPCWrappedNativeScope::UpdateWeakPointersAfterGC() {
  // Sweep waivers.
  if (mWaiverWrapperMap) {
    mWaiverWrapperMap->Sweep();
  }

  if (!js::IsCompartmentZoneSweepingOrCompacting(mCompartment)) {
    return;
  }

  if (!js::CompartmentHasLiveGlobal(mCompartment)) {
    GetWrappedNativeMap()->Clear();
    mWrappedNativeProtoMap->Clear();

    // The fields below are traced only if there's a live global in the
    // compartment, see TraceXPCGlobal. The compartment has no live globals so
    // clear these pointers here.
    if (mXrayExpandos.initialized()) {
      mXrayExpandos.destroy();
    }
    mIDProto = nullptr;
    mIIDProto = nullptr;
    mCIDProto = nullptr;
    return;
  }

  // Sweep mWrappedNativeMap for dying flat JS objects. Moving has already
  // been handled by XPCWrappedNative::FlatJSObjectMoved.
  for (auto iter = GetWrappedNativeMap()->Iter(); !iter.Done(); iter.Next()) {
    auto entry = static_cast<Native2WrappedNativeMap::Entry*>(iter.Get());
    XPCWrappedNative* wrapper = entry->value;
    JSObject* obj = wrapper->GetFlatJSObjectPreserveColor();
    JS_UpdateWeakPointerAfterGCUnbarriered(&obj);
    MOZ_ASSERT(!obj || obj == wrapper->GetFlatJSObjectPreserveColor());
    MOZ_ASSERT_IF(obj, js::GetObjectCompartment(obj) == mCompartment);
    if (!obj) {
      iter.Remove();
    }
  }

  // Sweep mWrappedNativeProtoMap for dying prototype JSObjects. Moving has
  // already been handled by XPCWrappedNativeProto::JSProtoObjectMoved.
  for (auto i = mWrappedNativeProtoMap->Iter(); !i.Done(); i.Next()) {
    auto entry = static_cast<ClassInfo2WrappedNativeProtoMap::Entry*>(i.Get());
    JSObject* obj = entry->value->GetJSProtoObjectPreserveColor();
    JS_UpdateWeakPointerAfterGCUnbarriered(&obj);
    MOZ_ASSERT_IF(obj, js::GetObjectCompartment(obj) == mCompartment);
    MOZ_ASSERT(!obj || obj == entry->value->GetJSProtoObjectPreserveColor());
    if (!obj) {
      i.Remove();
    }
  }
}

// static
void XPCWrappedNativeScope::SweepAllWrappedNativeTearOffs() {
  for (XPCWrappedNativeScope* cur : AllScopes()) {
    for (auto i = cur->mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
      auto entry = static_cast<Native2WrappedNativeMap::Entry*>(i.Get());
      entry->value->SweepTearOffs();
    }
  }
}

// static
void XPCWrappedNativeScope::SystemIsBeingShutDown() {
  // We're forcibly killing scopes, rather than allowing them to go away
  // when they're ready. As such, we need to do some cleanup before they
  // can safely be destroyed.

  for (XPCWrappedNativeScope* cur : AllScopes()) {
    // Give the Components object a chance to try to clean up.
    if (cur->mComponents) {
      cur->mComponents->SystemIsBeingShutDown();
    }

    // Null out these pointers to prevent ~ObjectPtr assertion failures if we
    // leaked things at shutdown.
    cur->mIDProto = nullptr;
    cur->mIIDProto = nullptr;
    cur->mCIDProto = nullptr;

    // Similarly, destroy mXrayExpandos to prevent assertion failures.
    if (cur->mXrayExpandos.initialized()) {
      cur->mXrayExpandos.destroy();
    }

    // Walk the protos first. Wrapper shutdown can leave dangling
    // proto pointers in the proto map.
    for (auto i = cur->mWrappedNativeProtoMap->Iter(); !i.Done(); i.Next()) {
      auto entry =
          static_cast<ClassInfo2WrappedNativeProtoMap::Entry*>(i.Get());
      entry->value->SystemIsBeingShutDown();
      i.Remove();
    }
    for (auto i = cur->mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
      auto entry = static_cast<Native2WrappedNativeMap::Entry*>(i.Get());
      entry->value->SystemIsBeingShutDown();
      i.Remove();
    }

    CompartmentPrivate* priv = CompartmentPrivate::Get(cur->Compartment());
    priv->SystemIsBeingShutDown();
  }
}

/***************************************************************************/

JSObject* XPCWrappedNativeScope::GetExpandoChain(HandleObject target) {
  MOZ_ASSERT(ObjectScope(target) == this);
  if (!mXrayExpandos.initialized()) {
    return nullptr;
  }
  return mXrayExpandos.lookup(target);
}

JSObject* XPCWrappedNativeScope::DetachExpandoChain(HandleObject target) {
  MOZ_ASSERT(ObjectScope(target) == this);
  if (!mXrayExpandos.initialized()) {
    return nullptr;
  }
  return mXrayExpandos.removeValue(target);
}

bool XPCWrappedNativeScope::SetExpandoChain(JSContext* cx, HandleObject target,
                                            HandleObject chain) {
  MOZ_ASSERT(ObjectScope(target) == this);
  MOZ_ASSERT(js::IsObjectInContextCompartment(target, cx));
  MOZ_ASSERT_IF(chain, ObjectScope(chain) == this);
  if (!mXrayExpandos.initialized() && !mXrayExpandos.init(cx)) {
    return false;
  }
  return mXrayExpandos.put(cx, target, chain);
}

/***************************************************************************/

// static
void XPCWrappedNativeScope::DebugDumpAllScopes(int16_t depth) {
#ifdef DEBUG
  depth--;

  // get scope count.
  int count = 0;
  for (XPCWrappedNativeScope* cur : AllScopes()) {
    mozilla::Unused << cur;
    count++;
  }

  XPC_LOG_ALWAYS(("chain of %d XPCWrappedNativeScope(s)", count));
  XPC_LOG_INDENT();
  if (depth) {
    for (XPCWrappedNativeScope* cur : AllScopes()) {
      cur->DebugDump(depth);
    }
  }
  XPC_LOG_OUTDENT();
#endif
}

void XPCWrappedNativeScope::DebugDump(int16_t depth) {
#ifdef DEBUG
  depth--;
  XPC_LOG_ALWAYS(("XPCWrappedNativeScope @ %p", this));
  XPC_LOG_INDENT();
  XPC_LOG_ALWAYS(("next @ %p", getNext()));
  XPC_LOG_ALWAYS(("mComponents @ %p", mComponents.get()));
  XPC_LOG_ALWAYS(("mCompartment @ %p", mCompartment));

  XPC_LOG_ALWAYS(("mWrappedNativeMap @ %p with %d wrappers(s)",
                  mWrappedNativeMap.get(), mWrappedNativeMap->Count()));
  // iterate contexts...
  if (depth && mWrappedNativeMap->Count()) {
    XPC_LOG_INDENT();
    for (auto i = mWrappedNativeMap->Iter(); !i.Done(); i.Next()) {
      auto entry = static_cast<Native2WrappedNativeMap::Entry*>(i.Get());
      entry->value->DebugDump(depth);
    }
    XPC_LOG_OUTDENT();
  }

  XPC_LOG_ALWAYS(("mWrappedNativeProtoMap @ %p with %d protos(s)",
                  mWrappedNativeProtoMap.get(),
                  mWrappedNativeProtoMap->Count()));
  // iterate contexts...
  if (depth && mWrappedNativeProtoMap->Count()) {
    XPC_LOG_INDENT();
    for (auto i = mWrappedNativeProtoMap->Iter(); !i.Done(); i.Next()) {
      auto entry =
          static_cast<ClassInfo2WrappedNativeProtoMap::Entry*>(i.Get());
      entry->value->DebugDump(depth);
    }
    XPC_LOG_OUTDENT();
  }
  XPC_LOG_OUTDENT();
#endif
}

void XPCWrappedNativeScope::AddSizeOfAllScopesIncludingThis(
    JSContext* cx, ScopeSizeInfo* scopeSizeInfo) {
  for (XPCWrappedNativeScope* cur : AllScopes()) {
    cur->AddSizeOfIncludingThis(cx, scopeSizeInfo);
  }
}

void XPCWrappedNativeScope::AddSizeOfIncludingThis(
    JSContext* cx, ScopeSizeInfo* scopeSizeInfo) {
  scopeSizeInfo->mScopeAndMapSize += scopeSizeInfo->mMallocSizeOf(this);
  scopeSizeInfo->mScopeAndMapSize +=
      mWrappedNativeMap->SizeOfIncludingThis(scopeSizeInfo->mMallocSizeOf);
  scopeSizeInfo->mScopeAndMapSize +=
      mWrappedNativeProtoMap->SizeOfIncludingThis(scopeSizeInfo->mMallocSizeOf);

  auto realmCb = [](JSContext*, void* aData, JS::Handle<JS::Realm*> aRealm) {
    auto* scopeSizeInfo = static_cast<ScopeSizeInfo*>(aData);
    JSObject* global = GetRealmGlobalOrNull(aRealm);
    if (global && dom::HasProtoAndIfaceCache(global)) {
      dom::ProtoAndIfaceCache* cache = dom::GetProtoAndIfaceCache(global);
      scopeSizeInfo->mProtoAndIfaceCacheSize +=
          cache->SizeOfIncludingThis(scopeSizeInfo->mMallocSizeOf);
    }
  };
  IterateRealmsInCompartment(cx, Compartment(), scopeSizeInfo, realmCb);

  // There are other XPCWrappedNativeScope members that could be measured;
  // the above ones have been seen by DMD to be worth measuring.  More stuff
  // may be added later.
}