1 files changed, 139 insertions, 0 deletions
diff --git a/toolkit/xre/dllservices/DynamicBlocklistWriter.cpp b/toolkit/xre/dllservices/DynamicBlocklistWriter.cpp
new file mode 100644
index 0000000000..e967d073c5
--- /dev/null
+++ b/toolkit/xre/dllservices/DynamicBlocklistWriter.cpp
@@ -0,0 +1,139 @@
+/* -*- 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 https://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/DynamicBlocklist.h"
+#include "mozilla/LauncherRegistryInfo.h"
+
+#include "nsISafeOutputStream.h"
+#include "nsNetUtil.h"
+
+namespace mozilla {
+#if ENABLE_TESTS
+nsDependentString testEntryString(DynamicBlockList::kTestDll,
+                                  DynamicBlockList::kTestDllBytes /
+                                      sizeof(DynamicBlockList::kTestDll[0]));
+#endif
+
+bool ShouldWriteEntry(const nsAString& name) {
+#if ENABLE_TESTS
+  return name != testEntryString;
+#else
+  return true;
+#endif
+}
+
+DynamicBlocklistWriter::DynamicBlocklistWriter(
+    RefPtr<dom::Promise> aPromise,
+    const nsTHashSet<nsStringCaseInsensitiveHashKey>& aBlocklist)
+    : mPromise(aPromise), mArraySize(0), mStringBufferSize(0) {
+  CheckedUint32 payloadSize;
+  bool hasTestEntry = false;
+  for (const nsAString& name : aBlocklist) {
+    if (ShouldWriteEntry(name)) {
+      payloadSize += name.Length() * sizeof(char16_t);
+      if (!payloadSize.isValid()) {
+        return;
+      }
+    } else {
+      hasTestEntry = true;
+    }
+  }
+
+  uint32_t entriesToWrite = aBlocklist.Count();
+  if (hasTestEntry) {
+    entriesToWrite -= 1;
+  }
+
+  mStringBufferSize = payloadSize.value();
+  mArraySize = (entriesToWrite + 1) * sizeof(DllBlockInfo);
+
+  payloadSize += mArraySize;
+  if (!payloadSize.isValid()) {
+    return;
+  }
+
+  mStringBuffer = MakeUnique<uint8_t[]>(mStringBufferSize);
+  Unused << mArray.resize(entriesToWrite + 1);  // aBlockEntries + sentinel
+
+  size_t currentStringOffset = 0;
+  size_t i = 0;
+  for (const nsAString& name : aBlocklist) {
+    if (!ShouldWriteEntry(name)) {
+      continue;
+    }
+    const uint32_t nameSize = name.Length() * sizeof(char16_t);
+
+    mArray[i].mMaxVersion = DllBlockInfo::ALL_VERSIONS;
+    mArray[i].mFlags = DllBlockInfo::Flags::FLAGS_DEFAULT;
+
+    // Copy the module's name to the string buffer and store its offset
+    // in mName.Buffer
+    memcpy(mStringBuffer.get() + currentStringOffset, name.BeginReading(),
+           nameSize);
+    mArray[i].mName.Buffer =
+        reinterpret_cast<wchar_t*>(mArraySize + currentStringOffset);
+    // Only keep mName.Length and leave mName.MaximumLength to be zero
+    mArray[i].mName.Length = nameSize;
+
+    currentStringOffset += nameSize;
+    ++i;
+  }
+}
+
+nsresult DynamicBlocklistWriter::WriteToFile(const nsAString& aName) const {
+  nsCOMPtr<nsIFile> file;
+  MOZ_TRY(NS_NewLocalFile(aName, true, getter_AddRefs(file)));
+
+  nsCOMPtr<nsIOutputStream> stream;
+  MOZ_TRY(NS_NewSafeLocalFileOutputStream(getter_AddRefs(stream), file));
+
+  MOZ_TRY(WriteValue(stream, kSignature));
+  MOZ_TRY(WriteValue(stream, kCurrentVersion));
+  MOZ_TRY(WriteValue(stream,
+                     static_cast<uint32_t>(mArraySize + mStringBufferSize)));
+  MOZ_TRY(WriteBuffer(stream, mArray.begin(), mArraySize));
+  MOZ_TRY(WriteBuffer(stream, mStringBuffer.get(), mStringBufferSize));
+
+  nsresult rv;
+  nsCOMPtr<nsISafeOutputStream> safeStream = do_QueryInterface(stream, &rv);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  return safeStream->Finish();
+}
+
+void DynamicBlocklistWriter::Run() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  nsresult rv = NS_ERROR_ABORT;
+
+  LauncherRegistryInfo regInfo;
+  LauncherResult<std::wstring> blocklistFile = regInfo.GetBlocklistFileName();
+  if (blocklistFile.isOk()) {
+    const wchar_t* rawBuffer = blocklistFile.inspect().c_str();
+    rv = WriteToFile(nsDependentString(rawBuffer));
+  }
+
+  NS_DispatchToMainThread(
+      // Don't capture mPromise by copy because we're not in the main thread
+      NS_NewRunnableFunction(__func__, [promise = std::move(mPromise), rv]() {
+        if (NS_SUCCEEDED(rv)) {
+          promise->MaybeResolve(JS::NullHandleValue);
+        } else {
+          promise->MaybeReject(rv);
+        }
+      }));
+}
+
+void DynamicBlocklistWriter::Cancel() {
+  MOZ_ASSERT(NS_IsMainThread());
+  if (mPromise) {
+    mPromise->MaybeReject(NS_ERROR_ABORT);
+  }
+}
+
+}  // namespace mozilla