diff options
Diffstat (limited to 'js/xpconnect/src/XPCWrappedJSClass.cpp')
| -rw-r--r-- | js/xpconnect/src/XPCWrappedJSClass.cpp | 1457 |
1 files changed, 1457 insertions, 0 deletions
diff --git a/js/xpconnect/src/XPCWrappedJSClass.cpp b/js/xpconnect/src/XPCWrappedJSClass.cpp new file mode 100644 index 000000000..2c9fd66bc --- /dev/null +++ b/js/xpconnect/src/XPCWrappedJSClass.cpp @@ -0,0 +1,1457 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* vim: set ts=8 sts=4 et sw=4 tw=99: */ +/* 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/. */ + +/* Sharable code and data for wrapper around JSObjects. */ + +#include "xpcprivate.h" +#include "jsprf.h" +#include "nsArrayEnumerator.h" +#include "nsContentUtils.h" +#include "nsWrapperCache.h" +#include "AccessCheck.h" +#include "nsJSUtils.h" +#include "mozilla/Attributes.h" +#include "mozilla/dom/BindingUtils.h" +#include "mozilla/dom/DOMException.h" +#include "mozilla/dom/DOMExceptionBinding.h" +#include "mozilla/jsipc/CrossProcessObjectWrappers.h" + +#include "jsapi.h" +#include "jsfriendapi.h" + +using namespace xpc; +using namespace JS; +using namespace mozilla; +using namespace mozilla::dom; + +NS_IMPL_ISUPPORTS(nsXPCWrappedJSClass, nsIXPCWrappedJSClass) + +// the value of this variable is never used - we use its address as a sentinel +static uint32_t zero_methods_descriptor; + +bool AutoScriptEvaluate::StartEvaluating(HandleObject scope) +{ + NS_PRECONDITION(!mEvaluated, "AutoScriptEvaluate::Evaluate should only be called once"); + + if (!mJSContext) + return true; + + mEvaluated = true; + + JS_BeginRequest(mJSContext); + mAutoCompartment.emplace(mJSContext, scope); + + // Saving the exception state keeps us from interfering with another script + // that may also be running on this context. This occurred first with the + // js debugger, as described in + // http://bugzilla.mozilla.org/show_bug.cgi?id=88130 but presumably could + // show up in any situation where a script calls into a wrapped js component + // on the same context, while the context has a nonzero exception state. + mState.emplace(mJSContext); + + return true; +} + +AutoScriptEvaluate::~AutoScriptEvaluate() +{ + if (!mJSContext || !mEvaluated) + return; + mState->restore(); + + JS_EndRequest(mJSContext); +} + +// It turns out that some errors may be not worth reporting. So, this +// function is factored out to manage that. +bool xpc_IsReportableErrorCode(nsresult code) +{ + if (NS_SUCCEEDED(code)) + return false; + + switch (code) { + // Error codes that we don't want to report as errors... + // These generally indicate bad interface design AFAIC. + case NS_ERROR_FACTORY_REGISTER_AGAIN: + case NS_BASE_STREAM_WOULD_BLOCK: + return false; + default: + return true; + } +} + +// A little stack-based RAII class to help management of the XPCJSContext +// PendingResult. +class MOZ_STACK_CLASS AutoSavePendingResult { +public: + explicit AutoSavePendingResult(XPCJSContext* xpccx) : + mXPCContext(xpccx) + { + // Save any existing pending result and reset to NS_OK for this invocation. + mSavedResult = xpccx->GetPendingResult(); + xpccx->SetPendingResult(NS_OK); + } + ~AutoSavePendingResult() { + mXPCContext->SetPendingResult(mSavedResult); + } +private: + XPCJSContext* mXPCContext; + nsresult mSavedResult; +}; + +// static +already_AddRefed<nsXPCWrappedJSClass> +nsXPCWrappedJSClass::GetNewOrUsed(JSContext* cx, REFNSIID aIID, bool allowNonScriptable) +{ + XPCJSContext* xpccx = nsXPConnect::GetContextInstance(); + IID2WrappedJSClassMap* map = xpccx->GetWrappedJSClassMap(); + RefPtr<nsXPCWrappedJSClass> clasp = map->Find(aIID); + + if (!clasp) { + nsCOMPtr<nsIInterfaceInfo> info; + nsXPConnect::XPConnect()->GetInfoForIID(&aIID, getter_AddRefs(info)); + if (info) { + bool canScript, isBuiltin; + if (NS_SUCCEEDED(info->IsScriptable(&canScript)) && (canScript || allowNonScriptable) && + NS_SUCCEEDED(info->IsBuiltinClass(&isBuiltin)) && !isBuiltin && + nsXPConnect::IsISupportsDescendant(info)) + { + clasp = new nsXPCWrappedJSClass(cx, aIID, info); + if (!clasp->mDescriptors) + clasp = nullptr; + } + } + } + return clasp.forget(); +} + +nsXPCWrappedJSClass::nsXPCWrappedJSClass(JSContext* cx, REFNSIID aIID, + nsIInterfaceInfo* aInfo) + : mContext(nsXPConnect::GetContextInstance()), + mInfo(aInfo), + mName(nullptr), + mIID(aIID), + mDescriptors(nullptr) +{ + mContext->GetWrappedJSClassMap()->Add(this); + + uint16_t methodCount; + if (NS_SUCCEEDED(mInfo->GetMethodCount(&methodCount))) { + if (methodCount) { + int wordCount = (methodCount/32)+1; + if (nullptr != (mDescriptors = new uint32_t[wordCount])) { + int i; + // init flags to 0; + for (i = wordCount-1; i >= 0; i--) + mDescriptors[i] = 0; + + for (i = 0; i < methodCount; i++) { + const nsXPTMethodInfo* info; + if (NS_SUCCEEDED(mInfo->GetMethodInfo(i, &info))) + SetReflectable(i, XPCConvert::IsMethodReflectable(*info)); + else { + delete [] mDescriptors; + mDescriptors = nullptr; + break; + } + } + } + } else { + mDescriptors = &zero_methods_descriptor; + } + } +} + +nsXPCWrappedJSClass::~nsXPCWrappedJSClass() +{ + if (mDescriptors && mDescriptors != &zero_methods_descriptor) + delete [] mDescriptors; + if (mContext) + mContext->GetWrappedJSClassMap()->Remove(this); + + if (mName) + free(mName); +} + +JSObject* +nsXPCWrappedJSClass::CallQueryInterfaceOnJSObject(JSContext* cx, + JSObject* jsobjArg, + REFNSIID aIID) +{ + RootedObject jsobj(cx, jsobjArg); + JSObject* id; + RootedValue retval(cx); + RootedObject retObj(cx); + bool success = false; + RootedValue fun(cx); + + // In bug 503926, we added a security check to make sure that we don't + // invoke content QI functions. In the modern world, this is probably + // unnecessary, because invoking QI involves passing an IID object to + // content, which will fail. But we do a belt-and-suspenders check to + // make sure that content can never trigger the rat's nest of code below. + // Once we completely turn off XPConnect for the web, this can definitely + // go away. + if (!AccessCheck::isChrome(jsobj) || + !AccessCheck::isChrome(js::UncheckedUnwrap(jsobj))) + { + return nullptr; + } + + // OK, it looks like we'll be calling into JS code. + AutoScriptEvaluate scriptEval(cx); + + // XXX we should install an error reporter that will send reports to + // the JS error console service. + if (!scriptEval.StartEvaluating(jsobj)) + return nullptr; + + // check upfront for the existence of the function property + HandleId funid = mContext->GetStringID(XPCJSContext::IDX_QUERY_INTERFACE); + if (!JS_GetPropertyById(cx, jsobj, funid, &fun) || fun.isPrimitive()) + return nullptr; + + // Ensure that we are asking for a scriptable interface. + // NB: It's important for security that this check is here rather + // than later, since it prevents untrusted objects from implementing + // some interfaces in JS and aggregating a trusted object to + // implement intentionally (for security) unscriptable interfaces. + // We so often ask for nsISupports that we can short-circuit the test... + if (!aIID.Equals(NS_GET_IID(nsISupports))) { + bool allowNonScriptable = mozilla::jsipc::IsWrappedCPOW(jsobj); + + nsCOMPtr<nsIInterfaceInfo> info; + nsXPConnect::XPConnect()->GetInfoForIID(&aIID, getter_AddRefs(info)); + if (!info) + return nullptr; + bool canScript, isBuiltin; + if (NS_FAILED(info->IsScriptable(&canScript)) || (!canScript && !allowNonScriptable) || + NS_FAILED(info->IsBuiltinClass(&isBuiltin)) || isBuiltin) + return nullptr; + } + + id = xpc_NewIDObject(cx, jsobj, aIID); + if (id) { + // Throwing NS_NOINTERFACE is the prescribed way to fail QI from JS. It + // is not an exception that is ever worth reporting, but we don't want + // to eat all exceptions either. + + { + RootedValue arg(cx, JS::ObjectValue(*id)); + success = JS_CallFunctionValue(cx, jsobj, fun, HandleValueArray(arg), &retval); + } + + if (!success && JS_IsExceptionPending(cx)) { + RootedValue jsexception(cx, NullValue()); + + if (JS_GetPendingException(cx, &jsexception)) { + nsresult rv; + if (jsexception.isObject()) { + // XPConnect may have constructed an object to represent a + // C++ QI failure. See if that is the case. + JS::Rooted<JSObject*> exceptionObj(cx, &jsexception.toObject()); + Exception* e = nullptr; + UNWRAP_OBJECT(Exception, &exceptionObj, e); + + if (e && + NS_SUCCEEDED(e->GetResult(&rv)) && + rv == NS_NOINTERFACE) { + JS_ClearPendingException(cx); + } + } else if (jsexception.isNumber()) { + // JS often throws an nsresult. + if (jsexception.isDouble()) + // Visual Studio 9 doesn't allow casting directly from + // a double to an enumeration type, contrary to + // 5.2.9(10) of C++11, so add an intermediate cast. + rv = (nsresult)(uint32_t)(jsexception.toDouble()); + else + rv = (nsresult)(jsexception.toInt32()); + + if (rv == NS_NOINTERFACE) + JS_ClearPendingException(cx); + } + } + } else if (!success) { + NS_WARNING("QI hook ran OOMed - this is probably a bug!"); + } + } + + if (success) + success = JS_ValueToObject(cx, retval, &retObj); + + return success ? retObj.get() : nullptr; +} + +/***************************************************************************/ + +static bool +GetNamedPropertyAsVariantRaw(XPCCallContext& ccx, + HandleObject aJSObj, + HandleId aName, + nsIVariant** aResult, + nsresult* pErr) +{ + nsXPTType type = nsXPTType((uint8_t)TD_INTERFACE_TYPE); + RootedValue val(ccx); + + return JS_GetPropertyById(ccx, aJSObj, aName, &val) && + XPCConvert::JSData2Native(aResult, val, type, + &NS_GET_IID(nsIVariant), pErr); +} + +// static +nsresult +nsXPCWrappedJSClass::GetNamedPropertyAsVariant(XPCCallContext& ccx, + JSObject* aJSObjArg, + const nsAString& aName, + nsIVariant** aResult) +{ + JSContext* cx = ccx.GetJSContext(); + RootedObject aJSObj(cx, aJSObjArg); + + AutoScriptEvaluate scriptEval(cx); + if (!scriptEval.StartEvaluating(aJSObj)) + return NS_ERROR_FAILURE; + + // Wrap the string in a Value after the AutoScriptEvaluate, so that the + // resulting value ends up in the correct compartment. + nsStringBuffer* buf; + RootedValue value(cx); + if (!XPCStringConvert::ReadableToJSVal(ccx, aName, &buf, &value)) + return NS_ERROR_OUT_OF_MEMORY; + if (buf) + buf->AddRef(); + + RootedId id(cx); + nsresult rv = NS_OK; + if (!JS_ValueToId(cx, value, &id) || + !GetNamedPropertyAsVariantRaw(ccx, aJSObj, id, aResult, &rv)) { + if (NS_FAILED(rv)) + return rv; + return NS_ERROR_FAILURE; + } + return NS_OK; +} + +/***************************************************************************/ + +// static +nsresult +nsXPCWrappedJSClass::BuildPropertyEnumerator(XPCCallContext& ccx, + JSObject* aJSObjArg, + nsISimpleEnumerator** aEnumerate) +{ + JSContext* cx = ccx.GetJSContext(); + RootedObject aJSObj(cx, aJSObjArg); + + AutoScriptEvaluate scriptEval(cx); + if (!scriptEval.StartEvaluating(aJSObj)) + return NS_ERROR_FAILURE; + + Rooted<IdVector> idArray(cx, IdVector(cx)); + if (!JS_Enumerate(cx, aJSObj, &idArray)) + return NS_ERROR_FAILURE; + + nsCOMArray<nsIProperty> propertyArray(idArray.length()); + RootedId idName(cx); + for (size_t i = 0; i < idArray.length(); i++) { + idName = idArray[i]; + + nsCOMPtr<nsIVariant> value; + nsresult rv; + if (!GetNamedPropertyAsVariantRaw(ccx, aJSObj, idName, + getter_AddRefs(value), &rv)) { + if (NS_FAILED(rv)) + return rv; + return NS_ERROR_FAILURE; + } + + RootedValue jsvalName(cx); + if (!JS_IdToValue(cx, idName, &jsvalName)) + return NS_ERROR_FAILURE; + + JSString* name = ToString(cx, jsvalName); + if (!name) + return NS_ERROR_FAILURE; + + nsAutoJSString autoStr; + if (!autoStr.init(cx, name)) + return NS_ERROR_FAILURE; + + nsCOMPtr<nsIProperty> property = + new xpcProperty(autoStr.get(), (uint32_t)autoStr.Length(), value); + + if (!propertyArray.AppendObject(property)) + return NS_ERROR_FAILURE; + } + + return NS_NewArrayEnumerator(aEnumerate, propertyArray); +} + +/***************************************************************************/ + +NS_IMPL_ISUPPORTS(xpcProperty, nsIProperty) + +xpcProperty::xpcProperty(const char16_t* aName, uint32_t aNameLen, + nsIVariant* aValue) + : mName(aName, aNameLen), mValue(aValue) +{ +} + +NS_IMETHODIMP xpcProperty::GetName(nsAString & aName) +{ + aName.Assign(mName); + return NS_OK; +} + +NS_IMETHODIMP xpcProperty::GetValue(nsIVariant * *aValue) +{ + nsCOMPtr<nsIVariant> rval = mValue; + rval.forget(aValue); + return NS_OK; +} + +/***************************************************************************/ +// This 'WrappedJSIdentity' class and singleton allow us to figure out if +// any given nsISupports* is implemented by a WrappedJS object. This is done +// using a QueryInterface call on the interface pointer with our ID. If +// that call returns NS_OK and the pointer is to our singleton, then the +// interface must be implemented by a WrappedJS object. NOTE: the +// 'WrappedJSIdentity' object is not a real XPCOM object and should not be +// used for anything else (hence it is declared in this implementation file). + +// {5C5C3BB0-A9BA-11d2-BA64-00805F8A5DD7} +#define NS_IXPCONNECT_WRAPPED_JS_IDENTITY_CLASS_IID \ +{ 0x5c5c3bb0, 0xa9ba, 0x11d2, \ + { 0xba, 0x64, 0x0, 0x80, 0x5f, 0x8a, 0x5d, 0xd7 } } + +class WrappedJSIdentity +{ + // no instance methods... +public: + NS_DECLARE_STATIC_IID_ACCESSOR(NS_IXPCONNECT_WRAPPED_JS_IDENTITY_CLASS_IID) + + static void* GetSingleton() + { + static WrappedJSIdentity* singleton = nullptr; + if (!singleton) + singleton = new WrappedJSIdentity(); + return (void*) singleton; + } +}; + +NS_DEFINE_STATIC_IID_ACCESSOR(WrappedJSIdentity, + NS_IXPCONNECT_WRAPPED_JS_IDENTITY_CLASS_IID) + +/***************************************************************************/ + +// static +bool +nsXPCWrappedJSClass::IsWrappedJS(nsISupports* aPtr) +{ + void* result; + NS_PRECONDITION(aPtr, "null pointer"); + return aPtr && + NS_OK == aPtr->QueryInterface(NS_GET_IID(WrappedJSIdentity), &result) && + result == WrappedJSIdentity::GetSingleton(); +} + +NS_IMETHODIMP +nsXPCWrappedJSClass::DelegatedQueryInterface(nsXPCWrappedJS* self, + REFNSIID aIID, + void** aInstancePtr) +{ + if (aIID.Equals(NS_GET_IID(nsIXPConnectJSObjectHolder))) { + NS_ADDREF(self); + *aInstancePtr = (void*) static_cast<nsIXPConnectJSObjectHolder*>(self); + return NS_OK; + } + + // Objects internal to xpconnect are the only objects that even know *how* + // to ask for this iid. And none of them bother refcounting the thing. + if (aIID.Equals(NS_GET_IID(WrappedJSIdentity))) { + // asking to find out if this is a wrapper object + *aInstancePtr = WrappedJSIdentity::GetSingleton(); + return NS_OK; + } + + if (aIID.Equals(NS_GET_IID(nsIPropertyBag))) { + // We only want to expose one implementation from our aggregate. + nsXPCWrappedJS* root = self->GetRootWrapper(); + + if (!root->IsValid()) { + *aInstancePtr = nullptr; + return NS_NOINTERFACE; + } + + NS_ADDREF(root); + *aInstancePtr = (void*) static_cast<nsIPropertyBag*>(root); + return NS_OK; + } + + // We can't have a cached wrapper. + if (aIID.Equals(NS_GET_IID(nsWrapperCache))) { + *aInstancePtr = nullptr; + return NS_NOINTERFACE; + } + + // QI on an XPCWrappedJS can run script, so we need an AutoEntryScript. + // This is inherently Gecko-specific. + // We check both nativeGlobal and nativeGlobal->GetGlobalJSObject() even + // though we have derived nativeGlobal from the JS global, because we know + // there are cases where this can happen. See bug 1094953. + nsIGlobalObject* nativeGlobal = + NativeGlobal(js::GetGlobalForObjectCrossCompartment(self->GetJSObject())); + NS_ENSURE_TRUE(nativeGlobal, NS_ERROR_FAILURE); + NS_ENSURE_TRUE(nativeGlobal->GetGlobalJSObject(), NS_ERROR_FAILURE); + AutoEntryScript aes(nativeGlobal, "XPCWrappedJS QueryInterface", + /* aIsMainThread = */ true); + XPCCallContext ccx(aes.cx()); + if (!ccx.IsValid()) { + *aInstancePtr = nullptr; + return NS_NOINTERFACE; + } + + // We support nsISupportsWeakReference iff the root wrapped JSObject + // claims to support it in its QueryInterface implementation. + if (aIID.Equals(NS_GET_IID(nsISupportsWeakReference))) { + // We only want to expose one implementation from our aggregate. + nsXPCWrappedJS* root = self->GetRootWrapper(); + + // Fail if JSObject doesn't claim support for nsISupportsWeakReference + if (!root->IsValid() || + !CallQueryInterfaceOnJSObject(ccx, root->GetJSObject(), aIID)) { + *aInstancePtr = nullptr; + return NS_NOINTERFACE; + } + + NS_ADDREF(root); + *aInstancePtr = (void*) static_cast<nsISupportsWeakReference*>(root); + return NS_OK; + } + + // Checks for any existing wrapper explicitly constructed for this iid. + // This includes the current 'self' wrapper. This also deals with the + // nsISupports case (for which it returns mRoot). + // Also check if asking for an interface from which one of our wrappers inherits. + if (nsXPCWrappedJS* sibling = self->FindOrFindInherited(aIID)) { + NS_ADDREF(sibling); + *aInstancePtr = sibling->GetXPTCStub(); + return NS_OK; + } + + // Check if the desired interface is a function interface. If so, we don't + // want to QI, because the function almost certainly doesn't have a QueryInterface + // property, and doesn't need one. + bool isFunc = false; + nsCOMPtr<nsIInterfaceInfo> info; + nsXPConnect::XPConnect()->GetInfoForIID(&aIID, getter_AddRefs(info)); + if (info && NS_SUCCEEDED(info->IsFunction(&isFunc)) && isFunc) { + RefPtr<nsXPCWrappedJS> wrapper; + RootedObject obj(RootingCx(), self->GetJSObject()); + nsresult rv = nsXPCWrappedJS::GetNewOrUsed(obj, aIID, getter_AddRefs(wrapper)); + + // Do the same thing we do for the "check for any existing wrapper" case above. + if (NS_SUCCEEDED(rv) && wrapper) { + *aInstancePtr = wrapper.forget().take()->GetXPTCStub(); + } + return rv; + } + + // else we do the more expensive stuff... + + // check if the JSObject claims to implement this interface + RootedObject jsobj(ccx, CallQueryInterfaceOnJSObject(ccx, self->GetJSObject(), + aIID)); + if (jsobj) { + // We can't use XPConvert::JSObject2NativeInterface() here + // since that can find a XPCWrappedNative directly on the + // proto chain, and we don't want that here. We need to find + // the actual JS object that claimed it supports the interface + // we're looking for or we'll potentially bypass security + // checks etc by calling directly through to a native found on + // the prototype chain. + // + // Instead, simply do the nsXPCWrappedJS part of + // XPConvert::JSObject2NativeInterface() here to make sure we + // get a new (or used) nsXPCWrappedJS. + RefPtr<nsXPCWrappedJS> wrapper; + nsresult rv = nsXPCWrappedJS::GetNewOrUsed(jsobj, aIID, getter_AddRefs(wrapper)); + if (NS_SUCCEEDED(rv) && wrapper) { + // We need to go through the QueryInterface logic to make + // this return the right thing for the various 'special' + // interfaces; e.g. nsIPropertyBag. + rv = wrapper->QueryInterface(aIID, aInstancePtr); + return rv; + } + } + + // else... + // no can do + *aInstancePtr = nullptr; + return NS_NOINTERFACE; +} + +JSObject* +nsXPCWrappedJSClass::GetRootJSObject(JSContext* cx, JSObject* aJSObjArg) +{ + RootedObject aJSObj(cx, aJSObjArg); + JSObject* result = CallQueryInterfaceOnJSObject(cx, aJSObj, + NS_GET_IID(nsISupports)); + if (!result) + result = aJSObj; + JSObject* inner = js::UncheckedUnwrap(result); + if (inner) + return inner; + return result; +} + +bool +nsXPCWrappedJSClass::GetArraySizeFromParam(JSContext* cx, + const XPTMethodDescriptor* method, + const nsXPTParamInfo& param, + uint16_t methodIndex, + uint8_t paramIndex, + nsXPTCMiniVariant* nativeParams, + uint32_t* result) const +{ + uint8_t argnum; + nsresult rv; + + rv = mInfo->GetSizeIsArgNumberForParam(methodIndex, ¶m, 0, &argnum); + if (NS_FAILED(rv)) + return false; + + const nsXPTParamInfo& arg_param = method->params[argnum]; + + // This should be enforced by the xpidl compiler, but it's not. + // See bug 695235. + MOZ_ASSERT(arg_param.GetType().TagPart() == nsXPTType::T_U32, + "size_is references parameter of invalid type."); + + if (arg_param.IsIndirect()) + *result = *(uint32_t*)nativeParams[argnum].val.p; + else + *result = nativeParams[argnum].val.u32; + + return true; +} + +bool +nsXPCWrappedJSClass::GetInterfaceTypeFromParam(JSContext* cx, + const XPTMethodDescriptor* method, + const nsXPTParamInfo& param, + uint16_t methodIndex, + const nsXPTType& type, + nsXPTCMiniVariant* nativeParams, + nsID* result) const +{ + uint8_t type_tag = type.TagPart(); + + if (type_tag == nsXPTType::T_INTERFACE) { + if (NS_SUCCEEDED(GetInterfaceInfo()-> + GetIIDForParamNoAlloc(methodIndex, ¶m, result))) { + return true; + } + } else if (type_tag == nsXPTType::T_INTERFACE_IS) { + uint8_t argnum; + nsresult rv; + rv = mInfo->GetInterfaceIsArgNumberForParam(methodIndex, + ¶m, &argnum); + if (NS_FAILED(rv)) + return false; + + const nsXPTParamInfo& arg_param = method->params[argnum]; + const nsXPTType& arg_type = arg_param.GetType(); + + if (arg_type.TagPart() == nsXPTType::T_IID) { + if (arg_param.IsIndirect()) { + nsID** p = (nsID**) nativeParams[argnum].val.p; + if (!p || !*p) + return false; + *result = **p; + } else { + nsID* p = (nsID*) nativeParams[argnum].val.p; + if (!p) + return false; + *result = *p; + } + return true; + } + } + return false; +} + +/* static */ void +nsXPCWrappedJSClass::CleanupPointerArray(const nsXPTType& datum_type, + uint32_t array_count, + void** arrayp) +{ + if (datum_type.IsInterfacePointer()) { + nsISupports** pp = (nsISupports**) arrayp; + for (uint32_t k = 0; k < array_count; k++) { + nsISupports* p = pp[k]; + NS_IF_RELEASE(p); + } + } else { + void** pp = (void**) arrayp; + for (uint32_t k = 0; k < array_count; k++) { + void* p = pp[k]; + if (p) free(p); + } + } +} + +/* static */ void +nsXPCWrappedJSClass::CleanupPointerTypeObject(const nsXPTType& type, + void** pp) +{ + MOZ_ASSERT(pp,"null pointer"); + if (type.IsInterfacePointer()) { + nsISupports* p = *((nsISupports**)pp); + if (p) p->Release(); + } else { + void* p = *((void**)pp); + if (p) free(p); + } +} + +void +nsXPCWrappedJSClass::CleanupOutparams(JSContext* cx, uint16_t methodIndex, + const nsXPTMethodInfo* info, nsXPTCMiniVariant* nativeParams, + bool inOutOnly, uint8_t n) const +{ + // clean up any 'out' params handed in + for (uint8_t i = 0; i < n; i++) { + const nsXPTParamInfo& param = info->params[i]; + if (!param.IsOut()) + continue; + + const nsXPTType& type = param.GetType(); + if (!type.deprecated_IsPointer()) + continue; + void* p = nativeParams[i].val.p; + if (!p) + continue; + + // The inOutOnly flag was introduced when consolidating two very + // similar code paths in CallMethod in bug 1175513. I don't know + // if and why the difference is necessary. + if (!inOutOnly || param.IsIn()) { + if (type.IsArray()) { + void** pp = *static_cast<void***>(p); + if (pp) { + // we need to get the array length and iterate the items + uint32_t array_count; + nsXPTType datum_type; + + if (NS_SUCCEEDED(mInfo->GetTypeForParam(methodIndex, ¶m, + 1, &datum_type)) && + datum_type.deprecated_IsPointer() && + GetArraySizeFromParam(cx, info, param, methodIndex, + i, nativeParams, &array_count) && + array_count) { + + CleanupPointerArray(datum_type, array_count, pp); + } + + // always release the array if it is inout + free(pp); + } + } else { + CleanupPointerTypeObject(type, static_cast<void**>(p)); + } + } + *static_cast<void**>(p) = nullptr; + } +} + +nsresult +nsXPCWrappedJSClass::CheckForException(XPCCallContext & ccx, + AutoEntryScript& aes, + const char * aPropertyName, + const char * anInterfaceName, + nsIException* aSyntheticException) +{ + JSContext * cx = ccx.GetJSContext(); + MOZ_ASSERT(cx == aes.cx()); + nsCOMPtr<nsIException> xpc_exception = aSyntheticException; + /* this one would be set by our error reporter */ + + XPCJSContext* xpccx = XPCJSContext::Get(); + + // Get this right away in case we do something below to cause JS code + // to run. + nsresult pending_result = xpccx->GetPendingResult(); + + RootedValue js_exception(cx); + bool is_js_exception = JS_GetPendingException(cx, &js_exception); + + /* JS might throw an expection whether the reporter was called or not */ + if (is_js_exception) { + if (!xpc_exception) + XPCConvert::JSValToXPCException(&js_exception, anInterfaceName, + aPropertyName, + getter_AddRefs(xpc_exception)); + + /* cleanup and set failed even if we can't build an exception */ + if (!xpc_exception) { + xpccx->SetPendingException(nullptr); // XXX necessary? + } + } + + // Clear the pending exception now, because xpc_exception might be JS- + // implemented, so invoking methods on it might re-enter JS, which we can't + // do with an exception on the stack. + aes.ClearException(); + + if (xpc_exception) { + nsresult e_result; + if (NS_SUCCEEDED(xpc_exception->GetResult(&e_result))) { + // Figure out whether or not we should report this exception. + bool reportable = xpc_IsReportableErrorCode(e_result); + if (reportable) { + // Ugly special case for GetInterface. It's "special" in the + // same way as QueryInterface in that a failure is not + // exceptional and shouldn't be reported. We have to do this + // check here instead of in xpcwrappedjs (like we do for QI) to + // avoid adding extra code to all xpcwrappedjs objects. + if (e_result == NS_ERROR_NO_INTERFACE && + !strcmp(anInterfaceName, "nsIInterfaceRequestor") && + !strcmp(aPropertyName, "getInterface")) { + reportable = false; + } + + // More special case, see bug 877760. + if (e_result == NS_ERROR_XPC_JSOBJECT_HAS_NO_FUNCTION_NAMED) { + reportable = false; + } + } + + // Try to use the error reporter set on the context to handle this + // error if it came from a JS exception. + if (reportable && is_js_exception) + { + // Note that we cleared the exception above, so we need to set it again, + // just so that we can tell the JS engine to pass it back to us via the + // error reporting callback. This is all very dumb. + JS_SetPendingException(cx, js_exception); + aes.ReportException(); + reportable = false; + } + + if (reportable) { + if (nsContentUtils::DOMWindowDumpEnabled()) { + static const char line[] = + "************************************************************\n"; + static const char preamble[] = + "* Call to xpconnect wrapped JSObject produced this error: *\n"; + static const char cant_get_text[] = + "FAILED TO GET TEXT FROM EXCEPTION\n"; + + fputs(line, stdout); + fputs(preamble, stdout); + nsCString text; + if (NS_SUCCEEDED(xpc_exception->ToString(cx, text)) && + !text.IsEmpty()) { + fputs(text.get(), stdout); + fputs("\n", stdout); + } else + fputs(cant_get_text, stdout); + fputs(line, stdout); + } + + // Log the exception to the JS Console, so that users can do + // something with it. + nsCOMPtr<nsIConsoleService> consoleService + (do_GetService(XPC_CONSOLE_CONTRACTID)); + if (nullptr != consoleService) { + nsresult rv; + nsCOMPtr<nsIScriptError> scriptError; + nsCOMPtr<nsISupports> errorData; + rv = xpc_exception->GetData(getter_AddRefs(errorData)); + if (NS_SUCCEEDED(rv)) + scriptError = do_QueryInterface(errorData); + + if (nullptr == scriptError) { + // No luck getting one from the exception, so + // try to cook one up. + scriptError = do_CreateInstance(XPC_SCRIPT_ERROR_CONTRACTID); + if (nullptr != scriptError) { + nsCString newMessage; + rv = xpc_exception->ToString(cx, newMessage); + if (NS_SUCCEEDED(rv)) { + // try to get filename, lineno from the first + // stack frame location. + int32_t lineNumber = 0; + nsString sourceName; + + nsCOMPtr<nsIStackFrame> location; + xpc_exception-> + GetLocation(getter_AddRefs(location)); + if (location) { + // Get line number w/o checking; 0 is ok. + location->GetLineNumber(cx, &lineNumber); + + // get a filename. + rv = location->GetFilename(cx, sourceName); + } + + rv = scriptError->InitWithWindowID(NS_ConvertUTF8toUTF16(newMessage), + sourceName, + EmptyString(), + lineNumber, 0, 0, + "XPConnect JavaScript", + nsJSUtils::GetCurrentlyRunningCodeInnerWindowID(cx)); + if (NS_FAILED(rv)) + scriptError = nullptr; + } + } + } + if (nullptr != scriptError) + consoleService->LogMessage(scriptError); + } + } + // Whether or not it passes the 'reportable' test, it might + // still be an error and we have to do the right thing here... + if (NS_FAILED(e_result)) { + xpccx->SetPendingException(xpc_exception); + return e_result; + } + } + } else { + // see if JS code signaled failure result without throwing exception + if (NS_FAILED(pending_result)) { + return pending_result; + } + } + return NS_ERROR_FAILURE; +} + +NS_IMETHODIMP +nsXPCWrappedJSClass::CallMethod(nsXPCWrappedJS* wrapper, uint16_t methodIndex, + const XPTMethodDescriptor* info_, + nsXPTCMiniVariant* nativeParams) +{ + Value* sp = nullptr; + Value* argv = nullptr; + uint8_t i; + nsresult retval = NS_ERROR_FAILURE; + bool success; + bool readyToDoTheCall = false; + nsID param_iid; + const nsXPTMethodInfo* info = static_cast<const nsXPTMethodInfo*>(info_); + const char* name = info->name; + bool foundDependentParam; + + // Make sure not to set the callee on ccx until after we've gone through + // the whole nsIXPCFunctionThisTranslator bit. That code uses ccx to + // convert natives to JSObjects, but we do NOT plan to pass those JSObjects + // to our real callee. + // + // We're about to call into script via an XPCWrappedJS, so we need an + // AutoEntryScript. This is probably Gecko-specific at this point, and + // definitely will be when we turn off XPConnect for the web. + nsIGlobalObject* nativeGlobal = + NativeGlobal(js::GetGlobalForObjectCrossCompartment(wrapper->GetJSObject())); + AutoEntryScript aes(nativeGlobal, "XPCWrappedJS method call", + /* aIsMainThread = */ true); + XPCCallContext ccx(aes.cx()); + if (!ccx.IsValid()) + return retval; + + JSContext* cx = ccx.GetJSContext(); + + if (!cx || !IsReflectable(methodIndex)) + return NS_ERROR_FAILURE; + + // [implicit_jscontext] and [optional_argc] have a different calling + // convention, which we don't support for JS-implemented components. + if (info->WantsOptArgc() || info->WantsContext()) { + const char* str = "IDL methods marked with [implicit_jscontext] " + "or [optional_argc] may not be implemented in JS"; + // Throw and warn for good measure. + JS_ReportErrorASCII(cx, "%s", str); + NS_WARNING(str); + return CheckForException(ccx, aes, name, GetInterfaceName()); + } + + RootedValue fval(cx); + RootedObject obj(cx, wrapper->GetJSObject()); + RootedObject thisObj(cx, obj); + + JSAutoCompartment ac(cx, obj); + + AutoValueVector args(cx); + AutoScriptEvaluate scriptEval(cx); + + XPCJSContext* xpccx = XPCJSContext::Get(); + AutoSavePendingResult apr(xpccx); + + // XXX ASSUMES that retval is last arg. The xpidl compiler ensures this. + uint8_t paramCount = info->num_args; + uint8_t argc = paramCount - + (paramCount && XPT_PD_IS_RETVAL(info->params[paramCount-1].flags) ? 1 : 0); + + if (!scriptEval.StartEvaluating(obj)) + goto pre_call_clean_up; + + xpccx->SetPendingException(nullptr); + + // We use js_Invoke so that the gcthings we use as args will be rooted by + // the engine as we do conversions and prepare to do the function call. + + // setup stack + + // if this isn't a function call then we don't need to push extra stuff + if (!(XPT_MD_IS_SETTER(info->flags) || XPT_MD_IS_GETTER(info->flags))) { + // We get fval before allocating the stack to avoid gc badness that can + // happen if the GetProperty call leaves our request and the gc runs + // while the stack we allocate contains garbage. + + // If the interface is marked as a [function] then we will assume that + // our JSObject is a function and not an object with a named method. + + bool isFunction; + if (NS_FAILED(mInfo->IsFunction(&isFunction))) + goto pre_call_clean_up; + + // In the xpidl [function] case we are making sure now that the + // JSObject is callable. If it is *not* callable then we silently + // fallback to looking up the named property... + // (because jst says he thinks this fallback is 'The Right Thing'.) + // + // In the normal (non-function) case we just lookup the property by + // name and as long as the object has such a named property we go ahead + // and try to make the call. If it turns out the named property is not + // a callable object then the JS engine will throw an error and we'll + // pass this along to the caller as an exception/result code. + + fval = ObjectValue(*obj); + if (isFunction && + JS_TypeOfValue(ccx, fval) == JSTYPE_FUNCTION) { + + // We may need to translate the 'this' for the function object. + + if (paramCount) { + const nsXPTParamInfo& firstParam = info->params[0]; + if (firstParam.IsIn()) { + const nsXPTType& firstType = firstParam.GetType(); + + if (firstType.IsInterfacePointer()) { + nsIXPCFunctionThisTranslator* translator; + + IID2ThisTranslatorMap* map = + mContext->GetThisTranslatorMap(); + + translator = map->Find(mIID); + + if (translator) { + nsCOMPtr<nsISupports> newThis; + if (NS_FAILED(translator-> + TranslateThis((nsISupports*)nativeParams[0].val.p, + getter_AddRefs(newThis)))) { + goto pre_call_clean_up; + } + if (newThis) { + RootedValue v(cx); + xpcObjectHelper helper(newThis); + bool ok = + XPCConvert::NativeInterface2JSObject( + &v, nullptr, helper, nullptr, + false, nullptr); + if (!ok) { + goto pre_call_clean_up; + } + thisObj = v.toObjectOrNull(); + if (!JS_WrapObject(cx, &thisObj)) + goto pre_call_clean_up; + } + } + } + } + } + } else { + if (!JS_GetProperty(cx, obj, name, &fval)) + goto pre_call_clean_up; + // XXX We really want to factor out the error reporting better and + // specifically report the failure to find a function with this name. + // This is what we do below if the property is found but is not a + // function. We just need to factor better so we can get to that + // reporting path from here. + + thisObj = obj; + } + } + + if (!args.resize(argc)) { + retval = NS_ERROR_OUT_OF_MEMORY; + goto pre_call_clean_up; + } + + argv = args.begin(); + sp = argv; + + // build the args + // NB: This assignment *looks* wrong because we haven't yet called our + // function. However, we *have* already entered the compartmen that we're + // about to call, and that's the global that we want here. In other words: + // we're trusting the JS engine to come up with a good global to use for + // our object (whatever it was). + for (i = 0; i < argc; i++) { + const nsXPTParamInfo& param = info->params[i]; + const nsXPTType& type = param.GetType(); + nsXPTType datum_type; + uint32_t array_count; + bool isArray = type.IsArray(); + RootedValue val(cx, NullValue()); + bool isSizedString = isArray ? + false : + type.TagPart() == nsXPTType::T_PSTRING_SIZE_IS || + type.TagPart() == nsXPTType::T_PWSTRING_SIZE_IS; + + + // verify that null was not passed for 'out' param + if (param.IsOut() && !nativeParams[i].val.p) { + retval = NS_ERROR_INVALID_ARG; + goto pre_call_clean_up; + } + + if (isArray) { + if (NS_FAILED(mInfo->GetTypeForParam(methodIndex, ¶m, 1, + &datum_type))) + goto pre_call_clean_up; + } else + datum_type = type; + + if (param.IsIn()) { + nsXPTCMiniVariant* pv; + + if (param.IsIndirect()) + pv = (nsXPTCMiniVariant*) nativeParams[i].val.p; + else + pv = &nativeParams[i]; + + if (datum_type.IsInterfacePointer() && + !GetInterfaceTypeFromParam(cx, info, param, methodIndex, + datum_type, nativeParams, + ¶m_iid)) + goto pre_call_clean_up; + + if (isArray || isSizedString) { + if (!GetArraySizeFromParam(cx, info, param, methodIndex, + i, nativeParams, &array_count)) + goto pre_call_clean_up; + } + + if (isArray) { + if (!XPCConvert::NativeArray2JS(&val, + (const void**)&pv->val, + datum_type, ¶m_iid, + array_count, nullptr)) + goto pre_call_clean_up; + } else if (isSizedString) { + if (!XPCConvert::NativeStringWithSize2JS(&val, + (const void*)&pv->val, + datum_type, + array_count, nullptr)) + goto pre_call_clean_up; + } else { + if (!XPCConvert::NativeData2JS(&val, &pv->val, type, + ¶m_iid, nullptr)) + goto pre_call_clean_up; + } + } + + if (param.IsOut() || param.IsDipper()) { + // create an 'out' object + RootedObject out_obj(cx, NewOutObject(cx)); + if (!out_obj) { + retval = NS_ERROR_OUT_OF_MEMORY; + goto pre_call_clean_up; + } + + if (param.IsIn()) { + if (!JS_SetPropertyById(cx, out_obj, + mContext->GetStringID(XPCJSContext::IDX_VALUE), + val)) { + goto pre_call_clean_up; + } + } + *sp++ = JS::ObjectValue(*out_obj); + } else + *sp++ = val; + } + + readyToDoTheCall = true; + +pre_call_clean_up: + // clean up any 'out' params handed in + CleanupOutparams(cx, methodIndex, info, nativeParams, /* inOutOnly = */ true, paramCount); + + // Make sure "this" doesn't get deleted during this call. + nsCOMPtr<nsIXPCWrappedJSClass> kungFuDeathGrip(this); + + if (!readyToDoTheCall) + return retval; + + // do the deed - note exceptions + + MOZ_ASSERT(!aes.HasException()); + + nsCOMPtr<nsIException> syntheticException; + RootedValue rval(cx); + if (XPT_MD_IS_GETTER(info->flags)) { + success = JS_GetProperty(cx, obj, name, &rval); + } else if (XPT_MD_IS_SETTER(info->flags)) { + rval = *argv; + success = JS_SetProperty(cx, obj, name, rval); + } else { + if (!fval.isPrimitive()) { + success = JS_CallFunctionValue(cx, thisObj, fval, args, &rval); + } else { + // The property was not an object so can't be a function. + // Let's build and 'throw' an exception. + + static const nsresult code = + NS_ERROR_XPC_JSOBJECT_HAS_NO_FUNCTION_NAMED; + static const char format[] = "%s \"%s\""; + const char * msg; + char* sz = nullptr; + + if (nsXPCException::NameAndFormatForNSResult(code, nullptr, &msg) && msg) + sz = JS_smprintf(format, msg, name); + + XPCConvert::ConstructException(code, sz, GetInterfaceName(), name, + nullptr, getter_AddRefs(syntheticException), + nullptr, nullptr); + if (sz) + JS_smprintf_free(sz); + success = false; + } + } + + if (!success) + return CheckForException(ccx, aes, name, GetInterfaceName(), + syntheticException); + + XPCJSContext::Get()->SetPendingException(nullptr); // XXX necessary? + + // convert out args and result + // NOTE: this is the total number of native params, not just the args + // Convert independent params only. + // When we later convert the dependent params (if any) we will know that + // the params upon which they depend will have already been converted - + // regardless of ordering. + + foundDependentParam = false; + for (i = 0; i < paramCount; i++) { + const nsXPTParamInfo& param = info->params[i]; + MOZ_ASSERT(!param.IsShared(), "[shared] implies [noscript]!"); + if (!param.IsOut() && !param.IsDipper()) + continue; + + const nsXPTType& type = param.GetType(); + if (type.IsDependent()) { + foundDependentParam = true; + continue; + } + + RootedValue val(cx); + uint8_t type_tag = type.TagPart(); + nsXPTCMiniVariant* pv; + + if (param.IsDipper()) + pv = (nsXPTCMiniVariant*) &nativeParams[i].val.p; + else + pv = (nsXPTCMiniVariant*) nativeParams[i].val.p; + + if (param.IsRetval()) + val = rval; + else if (argv[i].isPrimitive()) + break; + else { + RootedObject obj(cx, &argv[i].toObject()); + if (!JS_GetPropertyById(cx, obj, + mContext->GetStringID(XPCJSContext::IDX_VALUE), + &val)) + break; + } + + // setup allocator and/or iid + + if (type_tag == nsXPTType::T_INTERFACE) { + if (NS_FAILED(GetInterfaceInfo()-> + GetIIDForParamNoAlloc(methodIndex, ¶m, + ¶m_iid))) + break; + } + + if (!XPCConvert::JSData2Native(&pv->val, val, type, + ¶m_iid, nullptr)) + break; + } + + // if any params were dependent, then we must iterate again to convert them. + if (foundDependentParam && i == paramCount) { + for (i = 0; i < paramCount; i++) { + const nsXPTParamInfo& param = info->params[i]; + if (!param.IsOut()) + continue; + + const nsXPTType& type = param.GetType(); + if (!type.IsDependent()) + continue; + + RootedValue val(cx); + nsXPTCMiniVariant* pv; + nsXPTType datum_type; + uint32_t array_count; + bool isArray = type.IsArray(); + bool isSizedString = isArray ? + false : + type.TagPart() == nsXPTType::T_PSTRING_SIZE_IS || + type.TagPart() == nsXPTType::T_PWSTRING_SIZE_IS; + + pv = (nsXPTCMiniVariant*) nativeParams[i].val.p; + + if (param.IsRetval()) + val = rval; + else { + RootedObject obj(cx, &argv[i].toObject()); + if (!JS_GetPropertyById(cx, obj, + mContext->GetStringID(XPCJSContext::IDX_VALUE), + &val)) + break; + } + + // setup allocator and/or iid + + if (isArray) { + if (NS_FAILED(mInfo->GetTypeForParam(methodIndex, ¶m, 1, + &datum_type))) + break; + } else + datum_type = type; + + if (datum_type.IsInterfacePointer()) { + if (!GetInterfaceTypeFromParam(cx, info, param, methodIndex, + datum_type, nativeParams, + ¶m_iid)) + break; + } + + if (isArray || isSizedString) { + if (!GetArraySizeFromParam(cx, info, param, methodIndex, + i, nativeParams, &array_count)) + break; + } + + if (isArray) { + if (array_count && + !XPCConvert::JSArray2Native((void**)&pv->val, val, + array_count, datum_type, + ¶m_iid, nullptr)) + break; + } else if (isSizedString) { + if (!XPCConvert::JSStringWithSize2Native((void*)&pv->val, val, + array_count, datum_type, + nullptr)) + break; + } else { + if (!XPCConvert::JSData2Native(&pv->val, val, type, + ¶m_iid, + nullptr)) + break; + } + } + } + + if (i != paramCount) { + // We didn't manage all the result conversions! + // We have to cleanup any junk that *did* get converted. + CleanupOutparams(cx, methodIndex, info, nativeParams, /* inOutOnly = */ false, i); + } else { + // set to whatever the JS code might have set as the result + retval = xpccx->GetPendingResult(); + } + + return retval; +} + +const char* +nsXPCWrappedJSClass::GetInterfaceName() +{ + if (!mName) + mInfo->GetName(&mName); + return mName; +} + +static const JSClass XPCOutParamClass = { + "XPCOutParam", + 0, + JS_NULL_CLASS_OPS +}; + +bool +xpc::IsOutObject(JSContext* cx, JSObject* obj) +{ + return js::GetObjectJSClass(obj) == &XPCOutParamClass; +} + +JSObject* +xpc::NewOutObject(JSContext* cx) +{ + return JS_NewObject(cx, &XPCOutParamClass); +} + + +NS_IMETHODIMP +nsXPCWrappedJSClass::DebugDump(int16_t depth) +{ +#ifdef DEBUG + depth-- ; + XPC_LOG_ALWAYS(("nsXPCWrappedJSClass @ %x with mRefCnt = %d", this, mRefCnt.get())); + XPC_LOG_INDENT(); + char* name; + mInfo->GetName(&name); + XPC_LOG_ALWAYS(("interface name is %s", name)); + if (name) + free(name); + char * iid = mIID.ToString(); + XPC_LOG_ALWAYS(("IID number is %s", iid ? iid : "invalid")); + if (iid) + free(iid); + XPC_LOG_ALWAYS(("InterfaceInfo @ %x", mInfo.get())); + uint16_t methodCount = 0; + if (depth) { + uint16_t i; + nsCOMPtr<nsIInterfaceInfo> parent; + XPC_LOG_INDENT(); + mInfo->GetParent(getter_AddRefs(parent)); + XPC_LOG_ALWAYS(("parent @ %x", parent.get())); + mInfo->GetMethodCount(&methodCount); + XPC_LOG_ALWAYS(("MethodCount = %d", methodCount)); + mInfo->GetConstantCount(&i); + XPC_LOG_ALWAYS(("ConstantCount = %d", i)); + XPC_LOG_OUTDENT(); + } + XPC_LOG_ALWAYS(("mContext @ %x", mContext)); + XPC_LOG_ALWAYS(("mDescriptors @ %x count = %d", mDescriptors, methodCount)); + if (depth && mDescriptors && methodCount) { + depth--; + XPC_LOG_INDENT(); + for (uint16_t i = 0; i < methodCount; i++) { + XPC_LOG_ALWAYS(("Method %d is %s%s", \ + i, IsReflectable(i) ? "":" NOT ","reflectable")); + } + XPC_LOG_OUTDENT(); + depth++; + } + XPC_LOG_OUTDENT(); +#endif + return NS_OK; +} |