recovery: Implement a volume manager

This is a copy of the pre-binderized vold which has been converted to
use direct calls instead of sockets and stripped down to only what is
needed to support recovery.

Includes:
  * recovery: volmgr: remove unused IsSupported

    Change-Id: If8206658fdfb6108221806c09c99bf0a30f4a586
    Signed-off-by: Jesse Chan <jc@lineageos.org>

  * recovery: volmgr: remove filesystem checks

    Those checks are not strictly necessary and we are
    not building fsck tools for recovery for now.

    Remove those checks so volmgr can be useful.

    Change-Id: I87756c61b933b6cdccd281c6276b686fbd36019f
    Signed-off-by: Jesse Chan <jc@lineageos.org>

  * recovery: fixup `EmulatedVolume creating`

    Avoid dangling pointer. Instead of pointing to FstabEntry create copy.

    Change-Id: I57f76006db09a6add2c173f43175f0f6b848d87b

  * recovery: fix volmgr cleaning up

    Don't reset pointer to netlink manager
    Delete disks in stop() rather then in ~VolumeManager
    Call destroy() before deleting disks cause delete expects the
      disk to be destroyed
    Clear the lists or we would read garbage data on the next scan

    Change-Id: Idadfa1f33b7cb5f2f3c780848a99344a6608420e

  * recovery: handle interrupts in apply update menu

    Change-Id: I1f78f9196634353b77986545332d7d52a5f0c161

Change-Id: Ic82d929e052b5ba70ecf7b475e0a223d77d9687e
diff --git a/volume_manager/NetlinkHandler.h b/volume_manager/NetlinkHandler.h
new file mode 100644
index 0000000..09f474f
--- /dev/null
+++ b/volume_manager/NetlinkHandler.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ * Copyright (C) 2019 The LineageOS 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.
+ */
+
+#ifndef _NETLINKHANDLER_H
+#define _NETLINKHANDLER_H
+
+#include <sysutils/NetlinkListener.h>
+
+class NetlinkHandler : public NetlinkListener {
+  public:
+    explicit NetlinkHandler(int listenerSocket);
+    virtual ~NetlinkHandler();
+
+    bool start(void);
+    void stop(void);
+
+  protected:
+    virtual void onEvent(NetlinkEvent* evt);
+};
+#endif