Checkpoint of better dynamic device support.
This is the first in a series of changes that are designed to
introduce better support for dynamic block devices.
It starts by defining a new Volume object which represents a storage
endpoint that knows how to mount, unmount, and format itself. This
could be a filesystem directly on a partition, or it could be an
emulated FUSE filesystem, an ASEC, or an OBB.
These new volumes can be "stacked" so that unmounting a volume will
also unmount any volumes stacked above it. Volumes that provide
shared storage can also be asked to present themselves (through bind
mounts) into user-specific mount areas.
This change also adds a Disk class which is created based on block
kernel netlink events. Instead of waiting for partition events from
the kernel, it uses gptfdisk to read partition details and creates
the relevant Volume objects.
Change-Id: I0e8bc1f8f9dcb24405f5e795c0658998e22ae2f7
diff --git a/VolumeBase.h b/VolumeBase.h
new file mode 100644
index 0000000..04240b7
--- /dev/null
+++ b/VolumeBase.h
@@ -0,0 +1,124 @@
+/*
+ * Copyright (C) 2008 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.
+ */
+
+#ifndef ANDROID_VOLD_VOLUME_BASE_H
+#define ANDROID_VOLD_VOLUME_BASE_H
+
+#include "Utils.h"
+
+#include <utils/Errors.h>
+
+#include <sys/types.h>
+#include <list>
+#include <string>
+
+namespace android {
+namespace vold {
+
+enum class VolumeState {
+ kUnmounted,
+ kMounting,
+ kMounted,
+ kCorrupt,
+ kFormatting,
+ kUnmounting,
+};
+
+enum class VolumeType {
+ kPublic,
+ kPrivate,
+ kEmulated,
+ kAsec,
+ kObb,
+};
+
+// events:
+// volume_created private:127:4
+// volume_state private:127:4 mounted
+// volume_meta private:127:4 [fsGuid] [label]
+// volume_destroyed public:127:4
+
+// commands:
+// volume mount public:127:4 [primary]
+// volume unmount public:127:4
+// volume bind_user public:127:4 [userId]
+// volume unbind_user public:127:4 [userId]
+// volume bind_package private:4:1 [userId] [package]
+// volume unbind_package private:4:1 [userId] [package]
+
+/*
+ * Representation of a mounted volume ready for presentation.
+ *
+ * Various subclasses handle the different mounting prerequisites, such as
+ * encryption details, etc. Volumes can also be "stacked" above other
+ * volumes to help communicate dependencies. For example, an ASEC volume
+ * can be stacked on a vfat volume.
+ *
+ * Mounted volumes can be asked to manage bind mounts to present themselves
+ * to specific users on the device.
+ *
+ * When an unmount is requested, the volume recursively unmounts any stacked
+ * volumes and removes any bind mounts before finally unmounting itself.
+ */
+class VolumeBase {
+public:
+ virtual ~VolumeBase();
+
+ VolumeType getType() { return mType; }
+ const std::string& getId() { return mId; }
+ VolumeState getState() { return mState; }
+
+ void stackVolume(const std::shared_ptr<VolumeBase>& volume);
+ void unstackVolume(const std::shared_ptr<VolumeBase>& volume);
+
+ status_t mount();
+ status_t unmount();
+ status_t format();
+
+protected:
+ explicit VolumeBase(VolumeType type);
+
+ /* ID that uniquely references this disk */
+ std::string mId;
+
+ /* Manage bind mounts for this volume */
+ status_t mountBind(const std::string& source, const std::string& target);
+ status_t unmountBind(const std::string& target);
+
+ virtual status_t doMount() = 0;
+ virtual status_t doUnmount() = 0;
+ virtual status_t doFormat();
+
+private:
+ /* Volume type */
+ VolumeType mType;
+ /* Current state of volume */
+ VolumeState mState;
+
+ /* Volumes stacked on top of this volume */
+ std::list<std::shared_ptr<VolumeBase>> mStacked;
+ /* Currently active bind mounts */
+ std::list<std::string> mBindTargets;
+
+ void setState(VolumeState state);
+
+ DISALLOW_COPY_AND_ASSIGN(VolumeBase);
+};
+
+} // namespace vold
+} // namespace android
+
+#endif