init: Refactor service.h/cpp

Factors out utility functions into service_utils.h/cpp, so that they
can be reused by the upcoming native zygote.

Bug: 133443795
Test: Build and boot cuttlefish.
Change-Id: I0531b6f17561119c8cc33dd9ba375b351747fcfe
diff --git a/init/service_utils.h b/init/service_utils.h
new file mode 100644
index 0000000..f7502a9
--- /dev/null
+++ b/init/service_utils.h
@@ -0,0 +1,54 @@
+/*
+ * 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.
+ */
+
+#pragma once
+
+#include <sys/resource.h>
+#include <sys/types.h>
+
+#include <string>
+#include <vector>
+
+#include <cutils/iosched_policy.h>
+
+#include "result.h"
+
+namespace android {
+namespace init {
+
+struct NamespaceInfo {
+    unsigned flags;
+    // Pair of namespace type, path to name.
+    std::vector<std::pair<int, std::string>> namespaces_to_enter;
+};
+Result<Success> EnterNamespaces(const NamespaceInfo& info, const std::string& name, bool pre_apexd);
+
+struct ProcessAttributes {
+    std::string console;
+    IoSchedClass ioprio_class;
+    int ioprio_pri;
+    std::vector<std::pair<int, rlimit>> rlimits;
+    uid_t uid;
+    gid_t gid;
+    std::vector<gid_t> supp_gids;
+    int priority;
+};
+Result<Success> SetProcessAttributes(const ProcessAttributes& attr);
+
+Result<Success> WritePidToFiles(std::vector<std::string>* files);
+
+}  // namespace init
+}  // namespace android