diff options
Diffstat (limited to 'js/src/vm/JSContext.cpp')
| -rw-r--r-- | js/src/vm/JSContext.cpp | 1367 |
1 files changed, 1367 insertions, 0 deletions
diff --git a/js/src/vm/JSContext.cpp b/js/src/vm/JSContext.cpp new file mode 100644 index 0000000000..4d355dc828 --- /dev/null +++ b/js/src/vm/JSContext.cpp @@ -0,0 +1,1367 @@ +/* -*- 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/. */ + +/* + * JS execution context. + */ + +#include "vm/JSContext-inl.h" + +#include "mozilla/CheckedInt.h" +#include "mozilla/DebugOnly.h" +#include "mozilla/MemoryReporting.h" +#include "mozilla/Sprintf.h" +#include "mozilla/Utf8.h" // mozilla::ConvertUtf16ToUtf8 + +#include <string.h> +#ifdef ANDROID +# include <android/log.h> +# include <fstream> +# include <string> +#endif // ANDROID +#ifdef XP_WIN +# include <processthreadsapi.h> +#endif // XP_WIN + +#include "jsapi.h" // JS_SetNativeStackQuota +#include "jsexn.h" +#include "jstypes.h" + +#include "builtin/RegExp.h" // js::RegExpSearcherLastLimitSentinel +#include "frontend/FrontendContext.h" +#include "gc/GC.h" +#include "irregexp/RegExpAPI.h" +#include "jit/Simulator.h" +#include "js/CallAndConstruct.h" // JS::Call +#include "js/CharacterEncoding.h" +#include "js/ContextOptions.h" // JS::ContextOptions +#include "js/ErrorInterceptor.h" // JSErrorInterceptor +#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_* +#include "js/friend/StackLimits.h" // js::ReportOverRecursed +#include "js/MemoryCallbacks.h" +#include "js/Prefs.h" +#include "js/Printf.h" +#include "js/PropertyAndElement.h" // JS_GetProperty +#include "js/Stack.h" // JS::NativeStackSize, JS::NativeStackLimit, JS::NativeStackLimitMin +#include "util/DiagnosticAssertions.h" +#include "util/DifferentialTesting.h" +#include "util/DoubleToString.h" +#include "util/NativeStack.h" +#include "util/Text.h" +#include "util/WindowsWrapper.h" +#include "vm/BytecodeUtil.h" // JSDVG_IGNORE_STACK +#include "vm/ErrorObject.h" +#include "vm/ErrorReporting.h" +#include "vm/JSFunction.h" +#include "vm/JSObject.h" +#include "vm/PlainObject.h" // js::PlainObject +#include "vm/Realm.h" +#include "vm/StringType.h" // StringToNewUTF8CharsZ +#include "vm/ToSource.h" // js::ValueToSource + +#include "vm/Compartment-inl.h" +#include "vm/Stack-inl.h" + +using namespace js; + +#ifdef DEBUG +JSContext* js::MaybeGetJSContext() { + if (!TlsContext.init()) { + return nullptr; + } + return TlsContext.get(); +} +#endif + +bool js::AutoCycleDetector::init() { + MOZ_ASSERT(cyclic); + + AutoCycleDetector::Vector& vector = cx->cycleDetectorVector(); + + for (JSObject* obj2 : vector) { + if (MOZ_UNLIKELY(obj == obj2)) { + return true; + } + } + + if (!vector.append(obj)) { + return false; + } + + cyclic = false; + return true; +} + +js::AutoCycleDetector::~AutoCycleDetector() { + if (MOZ_LIKELY(!cyclic)) { + AutoCycleDetector::Vector& vec = cx->cycleDetectorVector(); + MOZ_ASSERT(vec.back() == obj); + if (vec.length() > 1) { + vec.popBack(); + } else { + // Avoid holding on to unused heap allocations. + vec.clearAndFree(); + } + } +} + +bool JSContext::init() { + TlsContext.set(this); + nativeStackBase_.emplace(GetNativeStackBase()); + + if (!fx.initInstance()) { + return false; + } + +#ifdef JS_SIMULATOR + simulator_ = jit::Simulator::Create(); + if (!simulator_) { + return false; + } +#endif + + isolate = irregexp::CreateIsolate(this); + if (!isolate) { + return false; + } + +#ifdef DEBUG + // Set the initialized_ last, so that ProtectedData checks will allow us to + // initialize this context before it becomes the runtime's active context. + initialized_ = true; +#endif + + return true; +} + +static void InitDefaultStackQuota(JSContext* cx) { + // Initialize stack quota to a reasonable default. Embedders can override this + // by calling JS_SetNativeStackQuota. + // + // NOTE: Firefox overrides these values. For the main thread this happens in + // XPCJSContext::Initialize. + +#if defined(MOZ_ASAN) || (defined(DEBUG) && !defined(XP_WIN)) + static constexpr JS::NativeStackSize MaxStackSize = + 2 * 128 * sizeof(size_t) * 1024; +#else + static constexpr JS::NativeStackSize MaxStackSize = + 128 * sizeof(size_t) * 1024; +#endif + JS_SetNativeStackQuota(cx, MaxStackSize); +} + +JSContext* js::NewContext(uint32_t maxBytes, JSRuntime* parentRuntime) { + AutoNoteSingleThreadedRegion anstr; + + MOZ_RELEASE_ASSERT(!TlsContext.get()); + +#if defined(DEBUG) || defined(JS_OOM_BREAKPOINT) + js::oom::SetThreadType(!parentRuntime ? js::THREAD_TYPE_MAIN + : js::THREAD_TYPE_WORKER); +#endif + + JSRuntime* runtime = js_new<JSRuntime>(parentRuntime); + if (!runtime) { + return nullptr; + } + + JSContext* cx = js_new<JSContext>(runtime, JS::ContextOptions()); + if (!cx) { + js_delete(runtime); + return nullptr; + } + + if (!cx->init()) { + js_delete(cx); + js_delete(runtime); + return nullptr; + } + + if (!runtime->init(cx, maxBytes)) { + runtime->destroyRuntime(); + js_delete(cx); + js_delete(runtime); + return nullptr; + } + + // Initialize stack quota last because simulators rely on the JSRuntime having + // been initialized. + InitDefaultStackQuota(cx); + + return cx; +} + +void js::DestroyContext(JSContext* cx) { + JS_AbortIfWrongThread(cx); + + MOZ_ASSERT(!cx->realm(), "Shouldn't destroy context with active realm"); + MOZ_ASSERT(!cx->activation(), "Shouldn't destroy context with activations"); + + cx->checkNoGCRooters(); + + // Cancel all off thread Ion compiles. Completed Ion compiles may try to + // interrupt this context. See HelperThread::handleIonWorkload. + CancelOffThreadIonCompile(cx->runtime()); + + cx->jobQueue = nullptr; + cx->internalJobQueue = nullptr; + SetContextProfilingStack(cx, nullptr); + + JSRuntime* rt = cx->runtime(); + + // Flush promise tasks executing in helper threads early, before any parts + // of the JSRuntime that might be visible to helper threads are torn down. + rt->offThreadPromiseState.ref().shutdown(cx); + + // Destroy the runtime along with its last context. + js::AutoNoteSingleThreadedRegion nochecks; + rt->destroyRuntime(); + js_delete_poison(cx); + js_delete_poison(rt); +} + +void JS::RootingContext::checkNoGCRooters() { +#ifdef DEBUG + for (auto const& stackRootPtr : stackRoots_) { + MOZ_ASSERT(stackRootPtr == nullptr); + } +#endif +} + +bool AutoResolving::alreadyStartedSlow() const { + MOZ_ASSERT(link); + AutoResolving* cursor = link; + do { + MOZ_ASSERT(this != cursor); + if (object.get() == cursor->object && id.get() == cursor->id && + kind == cursor->kind) { + return true; + } + } while (!!(cursor = cursor->link)); + return false; +} + +static void MaybeReportOutOfMemoryForDifferentialTesting() { + /* + * OOMs are non-deterministic, especially across different execution modes + * (e.g. interpreter vs JIT). When doing differential testing, print to stderr + * so that the fuzzers can detect this. + */ + if (js::SupportDifferentialTesting()) { + fprintf(stderr, "ReportOutOfMemory called\n"); + } +} + +/* + * Since memory has been exhausted, avoid the normal error-handling path which + * allocates an error object, report and callstack. Instead simply throw the + * static atom "out of memory". + * + * Furthermore, callers of ReportOutOfMemory (viz., malloc) assume a GC does + * not occur, so GC must be avoided or suppressed. + */ +void JSContext::onOutOfMemory() { + runtime()->hadOutOfMemory = true; + gc::AutoSuppressGC suppressGC(this); + + /* Report the oom. */ + if (JS::OutOfMemoryCallback oomCallback = runtime()->oomCallback) { + oomCallback(this, runtime()->oomCallbackData); + } + + // If we OOM early in process startup, this may be unavailable so just return + // instead of crashing unexpectedly. + if (MOZ_UNLIKELY(!runtime()->hasInitializedSelfHosting())) { + return; + } + + RootedValue oomMessage(this, StringValue(names().out_of_memory_)); + setPendingException(oomMessage, nullptr); + MOZ_ASSERT(status == JS::ExceptionStatus::Throwing); + status = JS::ExceptionStatus::OutOfMemory; + + reportResourceExhaustion(); +} + +JS_PUBLIC_API void js::ReportOutOfMemory(JSContext* cx) { + MaybeReportOutOfMemoryForDifferentialTesting(); + + cx->onOutOfMemory(); +} + +JS_PUBLIC_API void js::ReportLargeOutOfMemory(JSContext* cx) { + js::ReportOutOfMemory(cx); +} + +JS_PUBLIC_API void js::ReportOutOfMemory(FrontendContext* fc) { + MaybeReportOutOfMemoryForDifferentialTesting(); + + fc->onOutOfMemory(); +} + +static void MaybeReportOverRecursedForDifferentialTesting() { + /* + * We cannot make stack depth deterministic across different + * implementations (e.g. JIT vs. interpreter will differ in + * their maximum stack depth). + * However, we can detect externally when we hit the maximum + * stack depth which is useful for external testing programs + * like fuzzers. + */ + if (js::SupportDifferentialTesting()) { + fprintf(stderr, "ReportOverRecursed called\n"); + } +} + +void JSContext::onOverRecursed() { + // Try to construct an over-recursed error and then update the exception + // status to `OverRecursed`. Creating the error can fail, so check there + // is a reasonable looking exception pending before updating status. + JS_ReportErrorNumberASCII(this, GetErrorMessage, nullptr, + JSMSG_OVER_RECURSED); + if (isExceptionPending() && !isThrowingOutOfMemory()) { + MOZ_ASSERT(unwrappedException().isObject()); + MOZ_ASSERT(status == JS::ExceptionStatus::Throwing); + status = JS::ExceptionStatus::OverRecursed; + } + + reportResourceExhaustion(); +} + +JS_PUBLIC_API void js::ReportOverRecursed(JSContext* maybecx) { + MaybeReportOverRecursedForDifferentialTesting(); + + if (!maybecx) { + return; + } + + maybecx->onOverRecursed(); +} + +JS_PUBLIC_API void js::ReportOverRecursed(FrontendContext* fc) { + MaybeReportOverRecursedForDifferentialTesting(); + + fc->onOverRecursed(); +} + +void js::ReportOversizedAllocation(JSContext* cx, const unsigned errorNumber) { + // The JIT may optimize away allocations if it determines that they aren't + // used. This can affect whether we throw an exception when the size of an + // allocation exceeds implementation-defined limits (eg JSString::MAX_LENGTH). + // These errors aren't interesting for the purposes of differential fuzzing. + // We print a message so that fuzzers can detect this case. To simplify + // tooling updates, we use the same message as ReportOutOfMemory. + if (js::SupportDifferentialTesting()) { + fprintf(stderr, "ReportOutOfMemory called\n"); + } + + gc::AutoSuppressGC suppressGC(cx); + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, errorNumber); + + cx->reportResourceExhaustion(); +} + +void js::ReportAllocationOverflow(JSContext* cx) { + if (js::SupportDifferentialTesting()) { + fprintf(stderr, "ReportAllocationOverflow called\n"); + } + + if (!cx) { + return; + } + + cx->reportAllocationOverflow(); +} + +void js::ReportAllocationOverflow(FrontendContext* fc) { + fc->onAllocationOverflow(); +} + +/* |callee| requires a usage string provided by JS_DefineFunctionsWithHelp. */ +void js::ReportUsageErrorASCII(JSContext* cx, HandleObject callee, + const char* msg) { + RootedValue usage(cx); + if (!JS_GetProperty(cx, callee, "usage", &usage)) { + return; + } + + if (!usage.isString()) { + JS_ReportErrorASCII(cx, "%s", msg); + } else { + RootedString usageStr(cx, usage.toString()); + UniqueChars str = JS_EncodeStringToUTF8(cx, usageStr); + if (!str) { + return; + } + JS_ReportErrorUTF8(cx, "%s. Usage: %s", msg, str.get()); + } +} + +enum class PrintErrorKind { Error, Warning, Note }; + +static void PrintErrorLine(FILE* file, const char* prefix, + JSErrorReport* report) { + if (const char16_t* linebuf = report->linebuf()) { + UniqueChars line; + size_t n; + { + size_t linebufLen = report->linebufLength(); + + // This function is only used for shell command-line sorts of stuff where + // performance doesn't really matter, so just encode into max-sized + // memory. + mozilla::CheckedInt<size_t> utf8Len(linebufLen); + utf8Len *= 3; + if (utf8Len.isValid()) { + line = UniqueChars(js_pod_malloc<char>(utf8Len.value())); + if (line) { + n = mozilla::ConvertUtf16toUtf8({linebuf, linebufLen}, + {line.get(), utf8Len.value()}); + } + } + } + + const char* utf8buf; + if (line) { + utf8buf = line.get(); + } else { + static const char unavailableStr[] = "<context unavailable>"; + utf8buf = unavailableStr; + n = js_strlen(unavailableStr); + } + + fputs(":\n", file); + if (prefix) { + fputs(prefix, file); + } + + for (size_t i = 0; i < n; i++) { + fputc(utf8buf[i], file); + } + + // linebuf/utf8buf usually ends with a newline. If not, add one here. + if (n == 0 || utf8buf[n - 1] != '\n') { + fputc('\n', file); + } + + if (prefix) { + fputs(prefix, file); + } + + n = report->tokenOffset(); + for (size_t i = 0, j = 0; i < n; i++) { + if (utf8buf[i] == '\t') { + for (size_t k = (j + 8) & ~7; j < k; j++) { + fputc('.', file); + } + continue; + } + fputc('.', file); + j++; + } + fputc('^', file); + } +} + +static void PrintErrorLine(FILE* file, const char* prefix, + JSErrorNotes::Note* note) {} + +template <typename T> +static void PrintSingleError(FILE* file, JS::ConstUTF8CharsZ toStringResult, + T* report, PrintErrorKind kind) { + UniqueChars prefix; + if (report->filename) { + prefix = JS_smprintf("%s:", report->filename.c_str()); + } + + if (report->lineno) { + prefix = JS_smprintf("%s%u:%u ", prefix ? prefix.get() : "", report->lineno, + report->column.oneOriginValue()); + } + + if (kind != PrintErrorKind::Error) { + const char* kindPrefix = nullptr; + switch (kind) { + case PrintErrorKind::Error: + MOZ_CRASH("unreachable"); + case PrintErrorKind::Warning: + kindPrefix = "warning"; + break; + case PrintErrorKind::Note: + kindPrefix = "note"; + break; + } + + prefix = JS_smprintf("%s%s: ", prefix ? prefix.get() : "", kindPrefix); + } + + const char* message = + toStringResult ? toStringResult.c_str() : report->message().c_str(); + + /* embedded newlines -- argh! */ + const char* ctmp; + while ((ctmp = strchr(message, '\n')) != 0) { + ctmp++; + if (prefix) { + fputs(prefix.get(), file); + } + (void)fwrite(message, 1, ctmp - message, file); + message = ctmp; + } + + /* If there were no filename or lineno, the prefix might be empty */ + if (prefix) { + fputs(prefix.get(), file); + } + fputs(message, file); + + PrintErrorLine(file, prefix.get(), report); + fputc('\n', file); + + fflush(file); +} + +static void PrintErrorImpl(FILE* file, JS::ConstUTF8CharsZ toStringResult, + JSErrorReport* report, bool reportWarnings) { + MOZ_ASSERT(report); + + /* Conditionally ignore reported warnings. */ + if (report->isWarning() && !reportWarnings) { + return; + } + + PrintErrorKind kind = PrintErrorKind::Error; + if (report->isWarning()) { + kind = PrintErrorKind::Warning; + } + PrintSingleError(file, toStringResult, report, kind); + + if (report->notes) { + for (auto&& note : *report->notes) { + PrintSingleError(file, JS::ConstUTF8CharsZ(), note.get(), + PrintErrorKind::Note); + } + } +} + +JS_PUBLIC_API void JS::PrintError(FILE* file, JSErrorReport* report, + bool reportWarnings) { + PrintErrorImpl(file, JS::ConstUTF8CharsZ(), report, reportWarnings); +} + +JS_PUBLIC_API void JS::PrintError(FILE* file, + const JS::ErrorReportBuilder& builder, + bool reportWarnings) { + PrintErrorImpl(file, builder.toStringResult(), builder.report(), + reportWarnings); +} + +void js::ReportIsNotDefined(JSContext* cx, HandleId id) { + if (UniqueChars printable = + IdToPrintableUTF8(cx, id, IdToPrintableBehavior::IdIsIdentifier)) { + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, JSMSG_NOT_DEFINED, + printable.get()); + } +} + +void js::ReportIsNotDefined(JSContext* cx, Handle<PropertyName*> name) { + RootedId id(cx, NameToId(name)); + ReportIsNotDefined(cx, id); +} + +const char* NullOrUndefinedToCharZ(HandleValue v) { + MOZ_ASSERT(v.isNullOrUndefined()); + return v.isNull() ? "null" : "undefined"; +} + +void js::ReportIsNullOrUndefinedForPropertyAccess(JSContext* cx, HandleValue v, + int vIndex) { + MOZ_ASSERT(v.isNullOrUndefined()); + + if (vIndex == JSDVG_IGNORE_STACK) { + JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr, + JSMSG_CANT_CONVERT_TO, NullOrUndefinedToCharZ(v), + "object"); + return; + } + + UniqueChars bytes = DecompileValueGenerator(cx, vIndex, v, nullptr); + if (!bytes) { + return; + } + + if (strcmp(bytes.get(), "undefined") == 0 || + strcmp(bytes.get(), "null") == 0) { + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, JSMSG_NO_PROPERTIES, + bytes.get()); + } else { + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, + JSMSG_UNEXPECTED_TYPE, bytes.get(), + NullOrUndefinedToCharZ(v)); + } +} + +void js::ReportIsNullOrUndefinedForPropertyAccess(JSContext* cx, HandleValue v, + int vIndex, HandleId key) { + MOZ_ASSERT(v.isNullOrUndefined()); + + if (!JS::Prefs::property_error_message_fix()) { + ReportIsNullOrUndefinedForPropertyAccess(cx, v, vIndex); + return; + } + + RootedValue idVal(cx, IdToValue(key)); + RootedString idStr(cx, ValueToSource(cx, idVal)); + if (!idStr) { + return; + } + + UniqueChars keyStr = StringToNewUTF8CharsZ(cx, *idStr); + if (!keyStr) { + return; + } + + if (vIndex == JSDVG_IGNORE_STACK) { + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, JSMSG_PROPERTY_FAIL, + keyStr.get(), NullOrUndefinedToCharZ(v)); + return; + } + + UniqueChars bytes = DecompileValueGenerator(cx, vIndex, v, nullptr); + if (!bytes) { + return; + } + + if (strcmp(bytes.get(), "undefined") == 0 || + strcmp(bytes.get(), "null") == 0) { + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, JSMSG_PROPERTY_FAIL, + keyStr.get(), bytes.get()); + return; + } + + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, + JSMSG_PROPERTY_FAIL_EXPR, keyStr.get(), bytes.get(), + NullOrUndefinedToCharZ(v)); +} + +bool js::ReportValueError(JSContext* cx, const unsigned errorNumber, + int spindex, HandleValue v, HandleString fallback, + const char* arg1, const char* arg2) { + MOZ_ASSERT(js_ErrorFormatString[errorNumber].argCount >= 1); + MOZ_ASSERT(js_ErrorFormatString[errorNumber].argCount <= 3); + UniqueChars bytes = DecompileValueGenerator(cx, spindex, v, fallback); + if (!bytes) { + return false; + } + + JS_ReportErrorNumberUTF8(cx, GetErrorMessage, nullptr, errorNumber, + bytes.get(), arg1, arg2); + return false; +} + +JSObject* js::CreateErrorNotesArray(JSContext* cx, JSErrorReport* report) { + Rooted<ArrayObject*> notesArray(cx, NewDenseEmptyArray(cx)); + if (!notesArray) { + return nullptr; + } + + if (!report->notes) { + return notesArray; + } + + for (auto&& note : *report->notes) { + Rooted<PlainObject*> noteObj(cx, NewPlainObject(cx)); + if (!noteObj) { + return nullptr; + } + + RootedString messageStr(cx, note->newMessageString(cx)); + if (!messageStr) { + return nullptr; + } + RootedValue messageVal(cx, StringValue(messageStr)); + if (!DefineDataProperty(cx, noteObj, cx->names().message, messageVal)) { + return nullptr; + } + + RootedValue filenameVal(cx); + if (const char* filename = note->filename.c_str()) { + JS::UTF8Chars utf8chars(filename, strlen(filename)); + Rooted<JSString*> filenameStr(cx, NewStringCopyUTF8N(cx, utf8chars)); + if (!filenameStr) { + return nullptr; + } + filenameVal = StringValue(filenameStr); + } + if (!DefineDataProperty(cx, noteObj, cx->names().fileName, filenameVal)) { + return nullptr; + } + + RootedValue linenoVal(cx, Int32Value(note->lineno)); + if (!DefineDataProperty(cx, noteObj, cx->names().lineNumber, linenoVal)) { + return nullptr; + } + RootedValue columnVal(cx, Int32Value(note->column.oneOriginValue())); + if (!DefineDataProperty(cx, noteObj, cx->names().columnNumber, columnVal)) { + return nullptr; + } + + if (!NewbornArrayPush(cx, notesArray, ObjectValue(*noteObj))) { + return nullptr; + } + } + + return notesArray; +} + +void JSContext::recoverFromOutOfMemory() { + if (isExceptionPending()) { + MOZ_ASSERT(isThrowingOutOfMemory()); + clearPendingException(); + } +} + +void JSContext::reportAllocationOverflow() { + gc::AutoSuppressGC suppressGC(this); + JS_ReportErrorNumberASCII(this, GetErrorMessage, nullptr, + JSMSG_ALLOC_OVERFLOW); +} + +JS::StackKind JSContext::stackKindForCurrentPrincipal() { + return runningWithTrustedPrincipals() ? JS::StackForTrustedScript + : JS::StackForUntrustedScript; +} + +JS::NativeStackLimit JSContext::stackLimitForCurrentPrincipal() { + return stackLimit(stackKindForCurrentPrincipal()); +} + +JS_PUBLIC_API bool js::UseInternalJobQueues(JSContext* cx) { + // Internal job queue handling must be set up very early. Self-hosting + // initialization is as good a marker for that as any. + MOZ_RELEASE_ASSERT( + !cx->runtime()->hasInitializedSelfHosting(), + "js::UseInternalJobQueues must be called early during runtime startup."); + MOZ_ASSERT(!cx->jobQueue); + auto queue = MakeUnique<InternalJobQueue>(cx); + if (!queue) { + return false; + } + + cx->internalJobQueue = std::move(queue); + cx->jobQueue = cx->internalJobQueue.ref().get(); + + cx->runtime()->offThreadPromiseState.ref().initInternalDispatchQueue(); + MOZ_ASSERT(cx->runtime()->offThreadPromiseState.ref().initialized()); + + return true; +} + +#ifdef DEBUG +JSObject* InternalJobQueue::copyJobs(JSContext* cx) { + Rooted<ArrayObject*> jobs(cx, NewDenseEmptyArray(cx)); + if (!jobs) { + return nullptr; + } + + for (const JSObject* unwrappedJob : queue.get()) { + RootedObject job(cx, const_cast<JSObject*>(unwrappedJob)); + if (!cx->compartment()->wrap(cx, &job)) { + return nullptr; + } + + if (!NewbornArrayPush(cx, jobs, ObjectValue(*job))) { + return nullptr; + } + } + + return jobs; +} + +JS_PUBLIC_API JSObject* js::GetJobsInInternalJobQueue(JSContext* cx) { + MOZ_ASSERT(cx->internalJobQueue.ref()); + return cx->internalJobQueue->copyJobs(cx); +} +#endif + +JS_PUBLIC_API bool js::EnqueueJob(JSContext* cx, JS::HandleObject job) { + MOZ_ASSERT(cx->jobQueue); + return cx->jobQueue->enqueuePromiseJob(cx, nullptr, job, nullptr, nullptr); +} + +JS_PUBLIC_API void js::StopDrainingJobQueue(JSContext* cx) { + MOZ_ASSERT(cx->internalJobQueue.ref()); + cx->internalJobQueue->interrupt(); +} + +JS_PUBLIC_API void js::RunJobs(JSContext* cx) { + MOZ_ASSERT(cx->jobQueue); + cx->jobQueue->runJobs(cx); + JS::ClearKeptObjects(cx); +} + +JSObject* InternalJobQueue::getIncumbentGlobal(JSContext* cx) { + if (!cx->compartment()) { + return nullptr; + } + return cx->global(); +} + +bool InternalJobQueue::enqueuePromiseJob(JSContext* cx, + JS::HandleObject promise, + JS::HandleObject job, + JS::HandleObject allocationSite, + JS::HandleObject incumbentGlobal) { + MOZ_ASSERT(job); + if (!queue.pushBack(job)) { + ReportOutOfMemory(cx); + return false; + } + + JS::JobQueueMayNotBeEmpty(cx); + return true; +} + +void InternalJobQueue::runJobs(JSContext* cx) { + if (draining_ || interrupted_) { + return; + } + + while (true) { + cx->runtime()->offThreadPromiseState.ref().internalDrain(cx); + + // It doesn't make sense for job queue draining to be reentrant. At the + // same time we don't want to assert against it, because that'd make + // drainJobQueue unsafe for fuzzers. We do want fuzzers to test this, + // so we simply ignore nested calls of drainJobQueue. + draining_ = true; + + RootedObject job(cx); + JS::HandleValueArray args(JS::HandleValueArray::empty()); + RootedValue rval(cx); + + // Execute jobs in a loop until we've reached the end of the queue. + while (!queue.empty()) { + // A previous job might have set this flag. E.g., the js shell + // sets it if the `quit` builtin function is called. + if (interrupted_) { + break; + } + + job = queue.front(); + queue.popFront(); + + // If the next job is the last job in the job queue, allow + // skipping the standard job queuing behavior. + if (queue.empty()) { + JS::JobQueueIsEmpty(cx); + } + + AutoRealm ar(cx, &job->as<JSFunction>()); + { + if (!JS::Call(cx, UndefinedHandleValue, job, args, &rval)) { + // Nothing we can do about uncatchable exceptions. + if (!cx->isExceptionPending()) { + continue; + } + RootedValue exn(cx); + if (cx->getPendingException(&exn)) { + /* + * Clear the exception, because + * PrepareScriptEnvironmentAndInvoke will assert that we don't + * have one. + */ + cx->clearPendingException(); + js::ReportExceptionClosure reportExn(exn); + PrepareScriptEnvironmentAndInvoke(cx, cx->global(), reportExn); + } + } + } + } + + draining_ = false; + + if (interrupted_) { + interrupted_ = false; + break; + } + + queue.clear(); + + // It's possible a job added a new off-thread promise task. + if (!cx->runtime()->offThreadPromiseState.ref().internalHasPending()) { + break; + } + } +} + +bool InternalJobQueue::empty() const { return queue.empty(); } + +JSObject* InternalJobQueue::maybeFront() const { + if (queue.empty()) { + return nullptr; + } + + return queue.get().front(); +} + +class js::InternalJobQueue::SavedQueue : public JobQueue::SavedJobQueue { + public: + SavedQueue(JSContext* cx, Queue&& saved, bool draining) + : cx(cx), saved(cx, std::move(saved)), draining_(draining) { + MOZ_ASSERT(cx->internalJobQueue.ref()); + } + + ~SavedQueue() { + MOZ_ASSERT(cx->internalJobQueue.ref()); + cx->internalJobQueue->queue = std::move(saved.get()); + cx->internalJobQueue->draining_ = draining_; + } + + private: + JSContext* cx; + PersistentRooted<Queue> saved; + bool draining_; +}; + +js::UniquePtr<JS::JobQueue::SavedJobQueue> InternalJobQueue::saveJobQueue( + JSContext* cx) { + auto saved = + js::MakeUnique<SavedQueue>(cx, std::move(queue.get()), draining_); + if (!saved) { + // When MakeUnique's allocation fails, the SavedQueue constructor is never + // called, so this->queue is still initialized. (The move doesn't occur + // until the constructor gets called.) + ReportOutOfMemory(cx); + return nullptr; + } + + queue = Queue(SystemAllocPolicy()); + draining_ = false; + return saved; +} + +mozilla::GenericErrorResult<OOM> JSContext::alreadyReportedOOM() { + MOZ_ASSERT(isThrowingOutOfMemory()); + return mozilla::Err(JS::OOM()); +} + +mozilla::GenericErrorResult<JS::Error> JSContext::alreadyReportedError() { + return mozilla::Err(JS::Error()); +} + +JSContext::JSContext(JSRuntime* runtime, const JS::ContextOptions& options) + : RootingContext(runtime ? &runtime->gc.nursery() : nullptr), + runtime_(runtime), + options_(this, options), + measuringExecutionTime_(this, false), + jitActivation(this, nullptr), + isolate(this, nullptr), + activation_(this, nullptr), + profilingActivation_(nullptr), + entryMonitor(this, nullptr), + noExecuteDebuggerTop(this, nullptr), +#ifdef DEBUG + inUnsafeCallWithABI(this, false), + hasAutoUnsafeCallWithABI(this, false), +#endif +#ifdef JS_SIMULATOR + simulator_(this, nullptr), +#endif + dtoaState(this, nullptr), + suppressGC(this, 0), +#ifdef FUZZING_JS_FUZZILLI + executionHash(1), + executionHashInputs(0), +#endif +#ifdef DEBUG + noNurseryAllocationCheck(this, 0), + disableStrictProxyCheckingCount(this, 0), +#endif +#if defined(DEBUG) || defined(JS_OOM_BREAKPOINT) + runningOOMTest(this, false), +#endif + inUnsafeRegion(this, 0), + generationalDisabled(this, 0), + compactingDisabledCount(this, 0), +#ifdef DEBUG + regExpSearcherLastLimit(this, RegExpSearcherLastLimitSentinel), +#else + regExpSearcherLastLimit(this, 0), +#endif + frontendCollectionPool_(this), + suppressProfilerSampling(false), + tempLifoAlloc_(this, (size_t)TEMP_LIFO_ALLOC_PRIMARY_CHUNK_SIZE), + debuggerMutations(this, 0), + ionPcScriptCache(this, nullptr), + status(this, JS::ExceptionStatus::None), + unwrappedException_(this), + unwrappedExceptionStack_(this), +#ifdef DEBUG + hadResourceExhaustion_(this, false), +#endif + reportGranularity(this, JS_DEFAULT_JITREPORT_GRANULARITY), + resolvingList(this, nullptr), +#ifdef DEBUG + enteredPolicy(this, nullptr), +#endif + generatingError(this, false), + cycleDetectorVector_(this, this), + data(nullptr), + asyncStackForNewActivations_(this), + asyncCauseForNewActivations(this, nullptr), + asyncCallIsExplicit(this, false), + interruptCallbacks_(this), + interruptCallbackDisabled(this, false), + interruptBits_(0), + inlinedICScript_(this, nullptr), + jitStackLimit(JS::NativeStackLimitMin), + jitStackLimitNoInterrupt(this, JS::NativeStackLimitMin), + jobQueue(this, nullptr), + internalJobQueue(this), + canSkipEnqueuingJobs(this, false), + promiseRejectionTrackerCallback(this, nullptr), + promiseRejectionTrackerCallbackData(this, nullptr), + insideExclusiveDebuggerOnEval(this, nullptr) { + MOZ_ASSERT(static_cast<JS::RootingContext*>(this) == + JS::RootingContext::get(this)); +} + +JSContext::~JSContext() { +#ifdef DEBUG + // Clear the initialized_ first, so that ProtectedData checks will allow us to + // destroy this context even if the runtime is already gone. + initialized_ = false; +#endif + + /* Free the stuff hanging off of cx. */ + MOZ_ASSERT(!resolvingList); + + if (dtoaState) { + DestroyDtoaState(dtoaState); + } + + fx.destroyInstance(); + +#ifdef JS_SIMULATOR + js::jit::Simulator::Destroy(simulator_); +#endif + + if (isolate) { + irregexp::DestroyIsolate(isolate.ref()); + } + + TlsContext.set(nullptr); +} + +void JSContext::setRuntime(JSRuntime* rt) { + MOZ_ASSERT(!resolvingList); + MOZ_ASSERT(!compartment()); + MOZ_ASSERT(!activation()); + MOZ_ASSERT(!unwrappedException_.ref().initialized()); + MOZ_ASSERT(!unwrappedExceptionStack_.ref().initialized()); + MOZ_ASSERT(!asyncStackForNewActivations_.ref().initialized()); + + runtime_ = rt; +} + +#if defined(NIGHTLY_BUILD) +static bool IsOutOfMemoryException(JSContext* cx, const Value& v) { + return v == StringValue(cx->names().out_of_memory_); +} +#endif + +void JSContext::setPendingException(HandleValue v, Handle<SavedFrame*> stack) { +#if defined(NIGHTLY_BUILD) + do { + // Do not intercept exceptions if we are already + // in the exception interceptor. That would lead + // to infinite recursion. + if (this->runtime()->errorInterception.isExecuting) { + break; + } + + // Check whether we have an interceptor at all. + if (!this->runtime()->errorInterception.interceptor) { + break; + } + + // Don't report OOM exceptions. The interceptor isn't interested in those + // and they can confuse the interceptor because OOM can be thrown when we + // are not in a realm (atom allocation, for example). + if (IsOutOfMemoryException(this, v)) { + break; + } + + // Make sure that we do not call the interceptor from within + // the interceptor. + this->runtime()->errorInterception.isExecuting = true; + + // The interceptor must be infallible. + const mozilla::DebugOnly<bool> wasExceptionPending = + this->isExceptionPending(); + this->runtime()->errorInterception.interceptor->interceptError(this, v); + MOZ_ASSERT(wasExceptionPending == this->isExceptionPending()); + + this->runtime()->errorInterception.isExecuting = false; + } while (false); +#endif // defined(NIGHTLY_BUILD) + + // overRecursed_ is set after the fact by ReportOverRecursed. + this->status = JS::ExceptionStatus::Throwing; + this->unwrappedException() = v; + this->unwrappedExceptionStack() = stack; +} + +void JSContext::setPendingException(HandleValue value, + ShouldCaptureStack captureStack) { + Rooted<SavedFrame*> nstack(this); + if (captureStack == ShouldCaptureStack::Always || + realm()->shouldCaptureStackForThrow()) { + RootedObject stack(this); + if (!CaptureStack(this, &stack)) { + clearPendingException(); + } + if (stack) { + nstack = &stack->as<SavedFrame>(); + } + } + setPendingException(value, nstack); +} + +bool JSContext::getPendingException(MutableHandleValue rval) { + MOZ_ASSERT(isExceptionPending()); + + RootedValue exception(this, unwrappedException()); + if (zone()->isAtomsZone()) { + rval.set(exception); + return true; + } + + Rooted<SavedFrame*> stack(this, unwrappedExceptionStack()); + JS::ExceptionStatus prevStatus = status; + clearPendingException(); + if (!compartment()->wrap(this, &exception)) { + return false; + } + this->check(exception); + setPendingException(exception, stack); + status = prevStatus; + + rval.set(exception); + return true; +} + +bool JSContext::getPendingExceptionStack(MutableHandleValue rval) { + MOZ_ASSERT(isExceptionPending()); + + Rooted<SavedFrame*> exceptionStack(this, unwrappedExceptionStack()); + if (!exceptionStack) { + rval.setNull(); + return true; + } + if (zone()->isAtomsZone()) { + rval.setObject(*exceptionStack); + return true; + } + + RootedValue stack(this, ObjectValue(*exceptionStack)); + RootedValue exception(this, unwrappedException()); + JS::ExceptionStatus prevStatus = status; + clearPendingException(); + if (!compartment()->wrap(this, &exception) || + !compartment()->wrap(this, &stack)) { + return false; + } + this->check(stack); + setPendingException(exception, exceptionStack); + status = prevStatus; + + rval.set(stack); + return true; +} + +SavedFrame* JSContext::getPendingExceptionStack() { + return unwrappedExceptionStack(); +} + +bool JSContext::isClosingGenerator() { + return isExceptionPending() && + unwrappedException().isMagic(JS_GENERATOR_CLOSING); +} + +bool JSContext::isThrowingDebuggeeWouldRun() { + return isExceptionPending() && unwrappedException().isObject() && + unwrappedException().toObject().is<ErrorObject>() && + unwrappedException().toObject().as<ErrorObject>().type() == + JSEXN_DEBUGGEEWOULDRUN; +} + +bool JSContext::isRuntimeCodeGenEnabled(JS::RuntimeCode kind, + HandleString code) { + // Make sure that the CSP callback is installed and that it permits runtime + // code generation. + if (JSCSPEvalChecker allows = + runtime()->securityCallbacks->contentSecurityPolicyAllows) { + return allows(this, kind, code); + } + + return true; +} + +size_t JSContext::sizeOfExcludingThis( + mozilla::MallocSizeOf mallocSizeOf) const { + /* + * There are other JSContext members that could be measured; the following + * ones have been found by DMD to be worth measuring. More stuff may be + * added later. + */ + return cycleDetectorVector().sizeOfExcludingThis(mallocSizeOf) + + irregexp::IsolateSizeOfIncludingThis(isolate, mallocSizeOf); +} + +size_t JSContext::sizeOfIncludingThis( + mozilla::MallocSizeOf mallocSizeOf) const { + return mallocSizeOf(this) + sizeOfExcludingThis(mallocSizeOf); +} + +#ifdef DEBUG +bool JSContext::inAtomsZone() const { return zone_->isAtomsZone(); } +#endif + +void JSContext::trace(JSTracer* trc) { + cycleDetectorVector().trace(trc); + geckoProfiler().trace(trc); + if (isolate) { + irregexp::TraceIsolate(trc, isolate.ref()); + } +} + +JS::NativeStackLimit JSContext::stackLimitForJitCode(JS::StackKind kind) { +#ifdef JS_SIMULATOR + return simulator()->stackLimit(); +#else + return stackLimit(kind); +#endif +} + +void JSContext::resetJitStackLimit() { + // Note that, for now, we use the untrusted limit for ion. This is fine, + // because it's the most conservative limit, and if we hit it, we'll bail + // out of ion into the interpreter, which will do a proper recursion check. +#ifdef JS_SIMULATOR + jitStackLimit = jit::Simulator::StackLimit(); +#else + jitStackLimit = nativeStackLimit[JS::StackForUntrustedScript]; +#endif + jitStackLimitNoInterrupt = jitStackLimit; +} + +void JSContext::initJitStackLimit() { resetJitStackLimit(); } + +#ifdef JS_CRASH_DIAGNOSTICS +void ContextChecks::check(AbstractFramePtr frame, int argIndex) { + if (frame) { + check(frame.realm(), argIndex); + } +} +#endif + +void AutoEnterOOMUnsafeRegion::crash_impl(const char* reason) { + char msgbuf[1024]; + js::NoteIntentionalCrash(); + SprintfLiteral(msgbuf, "[unhandlable oom] %s", reason); +#ifndef DEBUG + // In non-DEBUG builds MOZ_CRASH normally doesn't print to stderr so we have + // to do this explicitly (the jit-test allow-unhandlable-oom annotation and + // fuzzers depend on it). + fprintf(stderr, "Hit MOZ_CRASH(%s) at %s:%d\n", msgbuf, __FILE__, __LINE__); +#endif + MOZ_CRASH_UNSAFE(msgbuf); +} + +mozilla::Atomic<AutoEnterOOMUnsafeRegion::AnnotateOOMAllocationSizeCallback, + mozilla::Relaxed> + AutoEnterOOMUnsafeRegion::annotateOOMSizeCallback(nullptr); + +void AutoEnterOOMUnsafeRegion::crash_impl(size_t size, const char* reason) { + { + JS::AutoSuppressGCAnalysis suppress; + if (annotateOOMSizeCallback) { + annotateOOMSizeCallback(size); + } + } + crash_impl(reason); +} + +void ExternalValueArray::trace(JSTracer* trc) { + if (Value* vp = begin()) { + TraceRootRange(trc, length(), vp, "js::ExternalValueArray"); + } +} + +#ifdef DEBUG +AutoUnsafeCallWithABI::AutoUnsafeCallWithABI(UnsafeABIStrictness strictness) + : cx_(TlsContext.get()), + nested_(cx_ ? cx_->hasAutoUnsafeCallWithABI : false), + nogc(cx_) { + if (!cx_) { + // This is a helper thread doing Ion or Wasm compilation - nothing to do. + return; + } + switch (strictness) { + case UnsafeABIStrictness::NoExceptions: + MOZ_ASSERT(!JS_IsExceptionPending(cx_)); + checkForPendingException_ = true; + break; + case UnsafeABIStrictness::AllowPendingExceptions: + checkForPendingException_ = !JS_IsExceptionPending(cx_); + break; + case UnsafeABIStrictness::AllowThrownExceptions: + checkForPendingException_ = false; + break; + } + + cx_->hasAutoUnsafeCallWithABI = true; +} + +AutoUnsafeCallWithABI::~AutoUnsafeCallWithABI() { + if (!cx_) { + return; + } + MOZ_ASSERT(cx_->hasAutoUnsafeCallWithABI); + if (!nested_) { + cx_->hasAutoUnsafeCallWithABI = false; + cx_->inUnsafeCallWithABI = false; + } + MOZ_ASSERT_IF(checkForPendingException_, !JS_IsExceptionPending(cx_)); +} +#endif + +#ifdef __wasi__ +JS_PUBLIC_API void js::IncWasiRecursionDepth(JSContext* cx) { + ++JS::RootingContext::get(cx)->wasiRecursionDepth; +} + +JS_PUBLIC_API void js::DecWasiRecursionDepth(JSContext* cx) { + MOZ_ASSERT(JS::RootingContext::get(cx)->wasiRecursionDepth > 0); + --JS::RootingContext::get(cx)->wasiRecursionDepth; +} + +JS_PUBLIC_API bool js::CheckWasiRecursionLimit(JSContext* cx) { + // WASI has two limits: + // 1) The stack pointer in linear memory that grows to zero. See + // --stack-first in js/src/shell/moz.build. + // 2) The JS::RootingContext::wasiRecursionDepth that counts recursion depth. + // Here we should check both. + if (JS::RootingContext::get(cx)->wasiRecursionDepth >= + JS::RootingContext::wasiRecursionDepthLimit) { + return false; + } + return true; +} +#endif // __wasi__ |