diff --git a/updater/updater_main.cpp b/updater/updater_main.cpp
new file mode 100644
index 0000000..dd22c13
--- /dev/null
+++ b/updater/updater_main.cpp
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <string>
+
+#include <android-base/logging.h>
+#include <android-base/parseint.h>
+#include <selinux/android.h>
+#include <selinux/label.h>
+#include <selinux/selinux.h>
+
+#include "edify/expr.h"
+#include "updater/blockimg.h"
+#include "updater/dynamic_partitions.h"
+#include "updater/install.h"
+#include "updater/updater.h"
+
+// Generated by the makefile, this function defines the
+// RegisterDeviceExtensions() function, which calls all the
+// registration functions for device-specific extensions.
+#include "register.inc"
+
+static void UpdaterLogger(android::base::LogId /* id */, android::base::LogSeverity /* severity */,
+                          const char* /* tag */, const char* /* file */, unsigned int /* line */,
+                          const char* message) {
+  fprintf(stdout, "%s\n", message);
+}
+
+int main(int argc, char** argv) {
+  // Various things log information to stdout or stderr more or less
+  // at random (though we've tried to standardize on stdout).  The
+  // log file makes more sense if buffering is turned off so things
+  // appear in the right order.
+  setbuf(stdout, nullptr);
+  setbuf(stderr, nullptr);
+
+  // We don't have logcat yet under recovery. Update logs will always be written to stdout
+  // (which is redirected to recovery.log).
+  android::base::InitLogging(argv, &UpdaterLogger);
+
+  if (argc != 4 && argc != 5) {
+    LOG(ERROR) << "unexpected number of arguments: " << argc;
+    return 1;
+  }
+
+  char* version = argv[1];
+  if ((version[0] != '1' && version[0] != '2' && version[0] != '3') || version[1] != '\0') {
+    // We support version 1, 2, or 3.
+    LOG(ERROR) << "wrong updater binary API; expected 1, 2, or 3; got " << argv[1];
+    return 1;
+  }
+
+  int fd;
+  if (!android::base::ParseInt(argv[2], &fd)) {
+    LOG(ERROR) << "Failed to parse fd in " << argv[2];
+    return 1;
+  }
+
+  std::string package_name = argv[3];
+
+  bool is_retry = false;
+  if (argc == 5) {
+    if (strcmp(argv[4], "retry") == 0) {
+      is_retry = true;
+    } else {
+      LOG(ERROR) << "unexpected argument: " << argv[4];
+      return 1;
+    }
+  }
+
+  // Configure edify's functions.
+  RegisterBuiltins();
+  RegisterInstallFunctions();
+  RegisterBlockImageFunctions();
+  RegisterDynamicPartitionsFunctions();
+  RegisterDeviceExtensions();
+
+  auto sehandle = selinux_android_file_context_handle();
+  selinux_android_set_sehandle(sehandle);
+
+  Updater updater;
+  if (!updater.Init(fd, package_name, is_retry, sehandle)) {
+    return 1;
+  }
+
+  if (!updater.RunUpdate()) {
+    return 1;
+  }
+
+  return 0;
+}
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