Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 609 insertions, 0 deletions

diff --git a/toolkit/components/telemetry/other/UntrustedModulesDataSerializer.cpp b/toolkit/components/telemetry/other/UntrustedModulesDataSerializer.cpp
new file mode 100644
index 0000000000..603b85fd88
--- /dev/null
+++ b/toolkit/components/telemetry/other/UntrustedModulesDataSerializer.cpp
@@ -0,0 +1,609 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "UntrustedModulesDataSerializer.h"
+
+#include "core/TelemetryCommon.h"
+#include "js/Array.h"               // JS::NewArrayObject
+#include "js/PropertyAndElement.h"  // JS_DefineElement, JS_DefineProperty, JS_GetProperty
+#include "jsapi.h"
+#include "mozilla/dom/ToJSValue.h"
+#include "nsITelemetry.h"
+#include "nsUnicharUtils.h"
+#include "nsXULAppAPI.h"
+
+#if defined(MOZ_GECKO_PROFILER)
+#  include "shared-libraries.h"
+#endif  // MOZ_GECKO_PROFILER
+
+namespace mozilla {
+namespace Telemetry {
+
+static const uint32_t kThirdPartyModulesPingVersion = 1;
+
+/**
+ * Limits the length of a string by removing the middle of the string, replacing
+ * with ellipsis.
+ * e.g. LimitStringLength("hello world", 6) would result in "he...d"
+ *
+ * @param  aStr            [in,out] The string to transform
+ * @param  aMaxFieldLength [in] The maximum length of the resulting string.
+ */
+static void LimitStringLength(nsAString& aStr, size_t aMaxFieldLength) {
+  if (aStr.Length() <= aMaxFieldLength) {
+    return;
+  }
+
+  constexpr auto kEllipsis = u"..."_ns;
+
+  if (aMaxFieldLength <= (kEllipsis.Length() + 3)) {
+    // An ellipsis is useless in this case, as it would obscure the string to
+    // the point that we cannot even determine the string's contents. We might
+    // as well just truncate.
+    aStr.Truncate(aMaxFieldLength);
+    return;
+  }
+
+  size_t cutPos = (aMaxFieldLength - kEllipsis.Length()) / 2;
+  size_t rightLen = aMaxFieldLength - kEllipsis.Length() - cutPos;
+  size_t cutLen = aStr.Length() - (cutPos + rightLen);
+
+  aStr.Replace(cutPos, cutLen, kEllipsis);
+}
+
+/**
+ * Adds a string property to a JS object, that's limited in length using
+ * LimitStringLength().
+ *
+ * @param  cx              [in] The JS context
+ * @param  aObj            [in] The object to add the property to
+ * @param  aName           [in] The name of the property to add
+ * @param  aVal            [in] The JS value of the resulting property.
+ * @param  aMaxFieldLength [in] The maximum length of the value
+ *                         (see LimitStringLength())
+ * @return true upon success
+ */
+static bool AddLengthLimitedStringProp(JSContext* cx,
+                                       JS::Handle<JSObject*> aObj,
+                                       const char* aName, const nsAString& aVal,
+                                       size_t aMaxFieldLength = MAX_PATH) {
+  JS::Rooted<JS::Value> jsval(cx);
+  nsAutoString shortVal(aVal);
+  LimitStringLength(shortVal, aMaxFieldLength);
+  jsval.setString(Common::ToJSString(cx, shortVal));
+  return JS_DefineProperty(cx, aObj, aName, jsval, JSPROP_ENUMERATE);
+};
+
+static JSString* ModuleVersionToJSString(JSContext* aCx,
+                                         const ModuleVersion& aVersion) {
+  auto [major, minor, patch, build] = aVersion.AsTuple();
+
+  constexpr auto dot = u"."_ns;
+
+  nsAutoString strVer;
+  strVer.AppendInt(major);
+  strVer.Append(dot);
+  strVer.AppendInt(minor);
+  strVer.Append(dot);
+  strVer.AppendInt(patch);
+  strVer.Append(dot);
+  strVer.AppendInt(build);
+
+  return Common::ToJSString(aCx, strVer);
+}
+
+/**
+ * Convert the given container object to a JavaScript array.
+ *
+ * @param  cx                [in] The JS context.
+ * @param  aRet              [out] This gets assigned to the newly created
+ *                           array object.
+ * @param  aContainer        [in] The source container to convert.
+ * @param  aElementConverter [in] A callable used to convert each element
+ *                           to a JS element. The form of this function is:
+ *                           bool(JSContext *cx,
+ *                                JS::MutableHandleValue aRet,
+ *                                const ElementT& aElement)
+ * @return true if aRet was successfully assigned to the new array object.
+ */
+template <typename T, typename Converter, typename... Args>
+static bool ContainerToJSArray(JSContext* cx, JS::MutableHandle<JSObject*> aRet,
+                               const T& aContainer,
+                               Converter&& aElementConverter, Args&&... aArgs) {
+  JS::Rooted<JSObject*> arr(cx, JS::NewArrayObject(cx, 0));
+  if (!arr) {
+    return false;
+  }
+
+  size_t i = 0;
+  for (auto&& item : aContainer) {
+    JS::Rooted<JS::Value> jsel(cx);
+    if (!aElementConverter(cx, &jsel, *item, std::forward<Args>(aArgs)...)) {
+      return false;
+    }
+    if (!JS_DefineElement(cx, arr, i, jsel, JSPROP_ENUMERATE)) {
+      return false;
+    }
+    ++i;
+  }
+
+  aRet.set(arr);
+  return true;
+}
+
+static bool SerializeModule(JSContext* aCx,
+                            JS::MutableHandle<JS::Value> aElement,
+                            const RefPtr<ModuleRecord>& aModule,
+                            uint32_t aFlags) {
+  if (!aModule) {
+    return false;
+  }
+
+  JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+  if (!obj) {
+    return false;
+  }
+
+  if (aFlags & nsITelemetry::INCLUDE_PRIVATE_FIELDS_IN_LOADEVENTS) {
+    JS::Rooted<JS::Value> jsFileObj(aCx);
+    if (!dom::ToJSValue(aCx, aModule->mResolvedDosName, &jsFileObj) ||
+        !JS_DefineProperty(aCx, obj, "dllFile", jsFileObj, JSPROP_ENUMERATE)) {
+      return false;
+    }
+  } else {
+    if (!AddLengthLimitedStringProp(aCx, obj, "resolvedDllName",
+                                    aModule->mSanitizedDllName)) {
+      return false;
+    }
+  }
+
+  if (aModule->mVersion.isSome()) {
+    JS::Rooted<JS::Value> jsModuleVersion(aCx);
+    jsModuleVersion.setString(
+        ModuleVersionToJSString(aCx, aModule->mVersion.ref()));
+    if (!JS_DefineProperty(aCx, obj, "fileVersion", jsModuleVersion,
+                           JSPROP_ENUMERATE)) {
+      return false;
+    }
+  }
+
+#if defined(MOZ_GECKO_PROFILER)
+  if (aModule->mResolvedDosName) {
+    nsAutoString path;
+    if (aModule->mResolvedDosName->GetPath(path) == NS_OK) {
+      SharedLibraryInfo info = SharedLibraryInfo::GetInfoFromPath(path.Data());
+      if (info.GetSize() > 0) {
+        nsCString breakpadId = info.GetEntry(0).GetBreakpadId();
+        if (!AddLengthLimitedStringProp(aCx, obj, "debugID",
+                                        NS_ConvertASCIItoUTF16(breakpadId))) {
+          return false;
+        }
+      }
+    }
+  }
+#endif  // MOZ_GECKO_PROFILER
+
+  if (aModule->mVendorInfo.isSome()) {
+    const char* propName;
+
+    const VendorInfo& vendorInfo = aModule->mVendorInfo.ref();
+    switch (vendorInfo.mSource) {
+      case VendorInfo::Source::Signature:
+        propName = "signedBy";
+        break;
+      case VendorInfo::Source::VersionInfo:
+        propName = "companyName";
+        break;
+      default:
+        MOZ_ASSERT_UNREACHABLE("Unknown VendorInfo Source!");
+        return false;
+    }
+
+    MOZ_ASSERT(!vendorInfo.mVendor.IsEmpty());
+    if (vendorInfo.mVendor.IsEmpty()) {
+      return false;
+    }
+
+    if (!AddLengthLimitedStringProp(aCx, obj, propName, vendorInfo.mVendor)) {
+      return false;
+    }
+  }
+
+  JS::Rooted<JS::Value> jsTrustFlags(aCx);
+  jsTrustFlags.setNumber(static_cast<uint32_t>(aModule->mTrustFlags));
+  if (!JS_DefineProperty(aCx, obj, "trustFlags", jsTrustFlags,
+                         JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  aElement.setObject(*obj);
+  return true;
+}
+
+/* static */
+bool UntrustedModulesDataSerializer::SerializeEvent(
+    JSContext* aCx, JS::MutableHandle<JS::Value> aElement,
+    const ProcessedModuleLoadEventContainer& aEventContainer,
+    const IndexMap& aModuleIndices) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  const ProcessedModuleLoadEvent& event = aEventContainer.mEvent;
+  if (!event) {
+    return false;
+  }
+
+  JS::Rooted<JSObject*> obj(aCx, JS_NewPlainObject(aCx));
+  if (!obj) {
+    return false;
+  }
+
+  JS::Rooted<JS::Value> jsProcessUptimeMS(aCx);
+  // Javascript doesn't like 64-bit integers; convert to double.
+  jsProcessUptimeMS.setNumber(static_cast<double>(event.mProcessUptimeMS));
+  if (!JS_DefineProperty(aCx, obj, "processUptimeMS", jsProcessUptimeMS,
+                         JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  if (event.mLoadDurationMS) {
+    JS::Rooted<JS::Value> jsLoadDurationMS(aCx);
+    jsLoadDurationMS.setNumber(event.mLoadDurationMS.value());
+    if (!JS_DefineProperty(aCx, obj, "loadDurationMS", jsLoadDurationMS,
+                           JSPROP_ENUMERATE)) {
+      return false;
+    }
+  }
+
+  JS::Rooted<JS::Value> jsThreadId(aCx);
+  jsThreadId.setNumber(static_cast<uint32_t>(event.mThreadId));
+  if (!JS_DefineProperty(aCx, obj, "threadID", jsThreadId, JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  nsDependentCString effectiveThreadName;
+  if (event.mThreadId == ::GetCurrentThreadId()) {
+    effectiveThreadName.Rebind("Main Thread"_ns, 0);
+  } else {
+    effectiveThreadName.Rebind(event.mThreadName, 0);
+  }
+
+  if (!effectiveThreadName.IsEmpty()) {
+    JS::Rooted<JS::Value> jsThreadName(aCx);
+    jsThreadName.setString(Common::ToJSString(aCx, effectiveThreadName));
+    if (!JS_DefineProperty(aCx, obj, "threadName", jsThreadName,
+                           JSPROP_ENUMERATE)) {
+      return false;
+    }
+  }
+
+  // Don't add this property unless mRequestedDllName differs from
+  // the associated module's mSanitizedDllName
+  if (!event.mRequestedDllName.IsEmpty() &&
+      !event.mRequestedDllName.Equals(event.mModule->mSanitizedDllName,
+                                      nsCaseInsensitiveStringComparator)) {
+    if (!AddLengthLimitedStringProp(aCx, obj, "requestedDllName",
+                                    event.mRequestedDllName)) {
+      return false;
+    }
+  }
+
+  nsAutoString strBaseAddress;
+  strBaseAddress.AppendLiteral(u"0x");
+  strBaseAddress.AppendInt(event.mBaseAddress, 16);
+
+  JS::Rooted<JS::Value> jsBaseAddress(aCx);
+  jsBaseAddress.setString(Common::ToJSString(aCx, strBaseAddress));
+  if (!JS_DefineProperty(aCx, obj, "baseAddress", jsBaseAddress,
+                         JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  uint32_t index;
+  if (!aModuleIndices.Get(event.mModule->mResolvedNtName, &index)) {
+    return false;
+  }
+
+  JS::Rooted<JS::Value> jsModuleIndex(aCx);
+  jsModuleIndex.setNumber(index);
+  if (!JS_DefineProperty(aCx, obj, "moduleIndex", jsModuleIndex,
+                         JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  JS::Rooted<JS::Value> jsIsDependent(aCx);
+  jsIsDependent.setBoolean(event.mIsDependent);
+  if (!JS_DefineProperty(aCx, obj, "isDependent", jsIsDependent,
+                         JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  JS::Rooted<JS::Value> jsLoadStatus(aCx);
+  jsLoadStatus.setNumber(event.mLoadStatus);
+  if (!JS_DefineProperty(aCx, obj, "loadStatus", jsLoadStatus,
+                         JSPROP_ENUMERATE)) {
+    return false;
+  }
+
+  aElement.setObject(*obj);
+
+  return true;
+}
+
+static nsDependentCString GetProcessTypeString(GeckoProcessType aType) {
+  nsDependentCString strProcType;
+  if (aType == GeckoProcessType_Default) {
+    strProcType.Rebind("browser"_ns, 0);
+  } else {
+    strProcType.Rebind(XRE_GeckoProcessTypeToString(aType));
+  }
+  return strProcType;
+}
+
+nsresult UntrustedModulesDataSerializer::GetPerProcObject(
+    const UntrustedModulesData& aData, JS::MutableHandle<JSObject*> aObj) {
+  JS::Rooted<JS::Value> jsProcType(mCx);
+  jsProcType.setString(
+      Common::ToJSString(mCx, GetProcessTypeString(aData.mProcessType)));
+  if (!JS_DefineProperty(mCx, aObj, "processType", jsProcType,
+                         JSPROP_ENUMERATE)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  JS::Rooted<JS::Value> jsElapsed(mCx);
+  jsElapsed.setNumber(aData.mElapsed.ToSecondsSigDigits());
+  if (!JS_DefineProperty(mCx, aObj, "elapsed", jsElapsed, JSPROP_ENUMERATE)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (aData.mXULLoadDurationMS.isSome()) {
+    JS::Rooted<JS::Value> jsXulLoadDurationMS(mCx);
+    jsXulLoadDurationMS.setNumber(aData.mXULLoadDurationMS.value());
+    if (!JS_DefineProperty(mCx, aObj, "xulLoadDurationMS", jsXulLoadDurationMS,
+                           JSPROP_ENUMERATE)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  JS::Rooted<JS::Value> jsSanitizationFailures(mCx);
+  jsSanitizationFailures.setNumber(aData.mSanitizationFailures);
+  if (!JS_DefineProperty(mCx, aObj, "sanitizationFailures",
+                         jsSanitizationFailures, JSPROP_ENUMERATE)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  JS::Rooted<JS::Value> jsTrustTestFailures(mCx);
+  jsTrustTestFailures.setNumber(aData.mTrustTestFailures);
+  if (!JS_DefineProperty(mCx, aObj, "trustTestFailures", jsTrustTestFailures,
+                         JSPROP_ENUMERATE)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  JS::Rooted<JSObject*> eventsArray(mCx);
+  if (!ContainerToJSArray(mCx, &eventsArray, aData.mEvents, &SerializeEvent,
+                          mIndexMap)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!JS_DefineProperty(mCx, aObj, "events", eventsArray, JSPROP_ENUMERATE)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  if (!(mFlags & nsITelemetry::EXCLUDE_STACKINFO_FROM_LOADEVENTS)) {
+    JS::Rooted<JSObject*> combinedStacksObj(
+        mCx, CreateJSStackObject(mCx, aData.mStacks));
+    if (!combinedStacksObj) {
+      return NS_ERROR_FAILURE;
+    }
+
+    if (!JS_DefineProperty(mCx, aObj, "combinedStacks", combinedStacksObj,
+                           JSPROP_ENUMERATE)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult UntrustedModulesDataSerializer::AddLoadEvents(
+    const UntrustedModuleLoadingEvents& aEvents,
+    JS::MutableHandle<JSObject*> aPerProcObj) {
+  JS::Rooted<JS::Value> eventsArrayVal(mCx);
+  if (!JS_GetProperty(mCx, aPerProcObj, "events", &eventsArrayVal) ||
+      !eventsArrayVal.isObject()) {
+    return NS_ERROR_FAILURE;
+  }
+
+  JS::Rooted<JSObject*> eventsArray(mCx, &eventsArrayVal.toObject());
+  bool isArray;
+  if (!JS::IsArrayObject(mCx, eventsArray, &isArray) && !isArray) {
+    return NS_ERROR_FAILURE;
+  }
+
+  uint32_t currentPos;
+  if (!GetArrayLength(mCx, eventsArray, &currentPos)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  for (auto item : aEvents) {
+    JS::Rooted<JS::Value> jsel(mCx);
+    if (!SerializeEvent(mCx, &jsel, *item, mIndexMap) ||
+        !JS_DefineElement(mCx, eventsArray, currentPos++, jsel,
+                          JSPROP_ENUMERATE)) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult UntrustedModulesDataSerializer::AddSingleData(
+    const UntrustedModulesData& aData) {
+  // Serialize each entry in the modules hashtable out to the "modules" array
+  // and store the indices in |mIndexMap|
+  for (const auto& entry : aData.mModules) {
+    if (!mIndexMap.WithEntryHandle(entry.GetKey(), [&](auto&& addPtr) {
+          if (!addPtr) {
+            addPtr.Insert(mCurModulesArrayIdx);
+
+            JS::Rooted<JS::Value> jsModule(mCx);
+            if (!SerializeModule(mCx, &jsModule, entry.GetData(), mFlags) ||
+                !JS_DefineElement(mCx, mModulesArray, mCurModulesArrayIdx,
+                                  jsModule, JSPROP_ENUMERATE)) {
+              return false;
+            }
+
+            ++mCurModulesArrayIdx;
+          }
+          return true;
+        })) {
+      return NS_ERROR_FAILURE;
+    }
+  }
+
+  if (mCurModulesArrayIdx >= mMaxModulesArrayLen) {
+    return NS_ERROR_CANNOT_CONVERT_DATA;
+  }
+
+  nsAutoCString strPid;
+  strPid.Append(GetProcessTypeString(aData.mProcessType));
+  strPid.AppendLiteral(".0x");
+  strPid.AppendInt(static_cast<uint32_t>(aData.mPid), 16);
+
+  if (mFlags & nsITelemetry::EXCLUDE_STACKINFO_FROM_LOADEVENTS) {
+    JS::Rooted<JS::Value> perProcVal(mCx);
+    if (JS_GetProperty(mCx, mPerProcObjContainer, strPid.get(), &perProcVal) &&
+        perProcVal.isObject()) {
+      // If a corresponding per-proc object already exists in the dictionary,
+      // and we skip to serialize CombinedStacks, we can add loading events
+      // into the JS object directly.
+      JS::Rooted<JSObject*> perProcObj(mCx, &perProcVal.toObject());
+      return AddLoadEvents(aData.mEvents, &perProcObj);
+    }
+  }
+
+  JS::Rooted<JSObject*> perProcObj(mCx, JS_NewPlainObject(mCx));
+  if (!perProcObj) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsresult rv = GetPerProcObject(aData, &perProcObj);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  JS::Rooted<JS::Value> jsPerProcObjValue(mCx);
+  jsPerProcObjValue.setObject(*perProcObj);
+  if (!JS_DefineProperty(mCx, mPerProcObjContainer, strPid.get(),
+                         jsPerProcObjValue, JSPROP_ENUMERATE)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+UntrustedModulesDataSerializer::UntrustedModulesDataSerializer(
+    JSContext* aCx, uint32_t aMaxModulesArrayLen, uint32_t aFlags)
+    : mCtorResult(NS_ERROR_FAILURE),
+      mCx(aCx),
+      mMainObj(mCx, JS_NewPlainObject(mCx)),
+      mModulesArray(mCx, JS::NewArrayObject(mCx, 0)),
+      mBlockedModulesArray(mCx, JS::NewArrayObject(mCx, 0)),
+      mPerProcObjContainer(mCx, JS_NewPlainObject(mCx)),
+      mMaxModulesArrayLen(aMaxModulesArrayLen),
+      mCurModulesArrayIdx(0),
+      mCurBlockedModulesArrayIdx(0),
+      mFlags(aFlags) {
+  if (!mMainObj || !mModulesArray || !mBlockedModulesArray ||
+      !mPerProcObjContainer) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> jsVersion(mCx);
+  jsVersion.setNumber(kThirdPartyModulesPingVersion);
+  if (!JS_DefineProperty(mCx, mMainObj, "structVersion", jsVersion,
+                         JSPROP_ENUMERATE)) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> jsModulesArrayValue(mCx);
+  jsModulesArrayValue.setObject(*mModulesArray);
+  if (!JS_DefineProperty(mCx, mMainObj, "modules", jsModulesArrayValue,
+                         JSPROP_ENUMERATE)) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> jsBlockedModulesArrayValue(mCx);
+  jsBlockedModulesArrayValue.setObject(*mBlockedModulesArray);
+  if (!JS_DefineProperty(mCx, mMainObj, "blockedModules",
+                         jsBlockedModulesArrayValue, JSPROP_ENUMERATE)) {
+    return;
+  }
+
+  JS::Rooted<JS::Value> jsPerProcObjContainerValue(mCx);
+  jsPerProcObjContainerValue.setObject(*mPerProcObjContainer);
+  if (!JS_DefineProperty(mCx, mMainObj, "processes", jsPerProcObjContainerValue,
+                         JSPROP_ENUMERATE)) {
+    return;
+  }
+
+  mCtorResult = NS_OK;
+}
+
+UntrustedModulesDataSerializer::operator bool() const {
+  return NS_SUCCEEDED(mCtorResult);
+}
+
+void UntrustedModulesDataSerializer::GetObject(
+    JS::MutableHandle<JS::Value> aRet) {
+  aRet.setObject(*mMainObj);
+}
+
+nsresult UntrustedModulesDataSerializer::Add(
+    const UntrustedModulesBackupData& aData) {
+  if (NS_FAILED(mCtorResult)) {
+    return mCtorResult;
+  }
+
+  for (const RefPtr<UntrustedModulesDataContainer>& container :
+       aData.Values()) {
+    if (!container) {
+      continue;
+    }
+
+    nsresult rv = AddSingleData(container->mData);
+    if (NS_FAILED(rv)) {
+      return rv;
+    }
+  }
+
+  return NS_OK;
+}
+
+nsresult UntrustedModulesDataSerializer::AddBlockedModules(
+    const nsTArray<nsDependentSubstring>& blockedModules) {
+  if (NS_FAILED(mCtorResult)) {
+    return mCtorResult;
+  }
+
+  if (blockedModules.Length() >= mMaxModulesArrayLen) {
+    return NS_ERROR_CANNOT_CONVERT_DATA;
+  }
+
+  for (const auto& blockedModule : blockedModules) {
+    JS::Rooted<JS::Value> jsBlockedModule(mCx);
+    jsBlockedModule.setString(Common::ToJSString(mCx, blockedModule));
+    if (!JS_DefineElement(mCx, mBlockedModulesArray, mCurBlockedModulesArrayIdx,
+                          jsBlockedModule, JSPROP_ENUMERATE)) {
+      return NS_ERROR_FAILURE;
+    }
+    ++mCurBlockedModulesArrayIdx;
+  }
+
+  return NS_OK;
+}
+
+}  // namespace Telemetry
+}  // namespace mozilla