Move even more vold commands over to Binder.

This moves fstrim, obb and appfuse commands over to the new Binder
interface.  This change also separates creating/destroying and
mounting/unmounting of OBB volumes, which means they finally flow
nicely into the modern VolumeInfo/VolumeBase design.

We now generate unique identifiers for all OBB volumes, instead of
using a shady MD5 hash.

Change all "loop" and "dm" devices to tag the kernel resources with
a vold-specific prefix so that we can clean them up if vold crashes;
there are new destroyAll() methods that handle this cleanup.

Move appfuse mounting/unmounting into VolumeManager so it can be
shared.  Move various model objects into a separate directory to
tidy things up.

Test: cts-tradefed run commandAndExit cts-dev -m CtsOsTestCases -t android.os.storage.cts.StorageManagerTest
Bug: 13758960
Change-Id: I7294e32b3fb6efe07cb3b77bd20166e70b66958f
diff --git a/model/ObbVolume.cpp b/model/ObbVolume.cpp
new file mode 100644
index 0000000..709c7a3
--- /dev/null
+++ b/model/ObbVolume.cpp
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2017 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 "fs/Vfat.h"
+#include "Devmapper.h"
+#include "Loop.h"
+#include "ObbVolume.h"
+#include "Utils.h"
+#include "VoldUtil.h"
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <cutils/fs.h>
+#include <private/android_filesystem_config.h>
+
+#include <fcntl.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/sysmacros.h>
+#include <sys/wait.h>
+
+using android::base::StringPrintf;
+using android::base::unique_fd;
+
+namespace android {
+namespace vold {
+
+ObbVolume::ObbVolume(int id, const std::string& sourcePath, const std::string& sourceKey,
+        gid_t ownerGid) : VolumeBase(Type::kObb) {
+    setId(StringPrintf("obb:%d", id));
+    mSourcePath = sourcePath;
+    mSourceKey = sourceKey;
+    mOwnerGid = ownerGid;
+}
+
+ObbVolume::~ObbVolume() {
+}
+
+status_t ObbVolume::doCreate() {
+    if (Loop::create(mSourcePath, mLoopPath)) {
+        PLOG(ERROR) << getId() << " failed to create loop";
+        return -1;
+    }
+
+    if (!mSourceKey.empty()) {
+        unsigned long nr_sec = 0;
+        {
+            unique_fd loop_fd(open(mLoopPath.c_str(), O_RDWR | O_CLOEXEC));
+            if (loop_fd.get() == -1) {
+                PLOG(ERROR) << getId() << " failed to open loop";
+                return -1;
+            }
+
+            get_blkdev_size(loop_fd.get(), &nr_sec);
+            if (nr_sec == 0) {
+                PLOG(ERROR) << getId() << " failed to get loop size";
+                return -1;
+            }
+        }
+
+        char tmp[PATH_MAX];
+        if (Devmapper::create(getId().c_str(), mLoopPath.c_str(), mSourceKey.c_str(), nr_sec,
+                tmp, PATH_MAX)) {
+            PLOG(ERROR) << getId() << " failed to create dm";
+            return -1;
+        }
+        mDmPath = tmp;
+        mMountPath = mDmPath;
+    } else {
+        mMountPath = mLoopPath;
+    }
+    return OK;
+}
+
+status_t ObbVolume::doDestroy() {
+    if (!mDmPath.empty() && Devmapper::destroy(getId().c_str())) {
+        PLOG(WARNING) << getId() << " failed to destroy dm";
+    }
+    if (!mLoopPath.empty() && Loop::destroyByDevice(mLoopPath.c_str())) {
+        PLOG(WARNING) << getId() << " failed to destroy loop";
+    }
+    mDmPath.clear();
+    mLoopPath.clear();
+    return OK;
+}
+
+status_t ObbVolume::doMount() {
+    auto path = StringPrintf("/mnt/obb/%s", getId().c_str());
+    setPath(path);
+
+    if (fs_prepare_dir(path.c_str(), 0700, AID_ROOT, AID_ROOT)) {
+        PLOG(ERROR) << getId() << " failed to create mount point";
+        return -1;
+    }
+    if (android::vold::vfat::Mount(mMountPath, path,
+            true, false, true, 0, mOwnerGid, 0227, false)) {
+        PLOG(ERROR) << getId() << " failed to mount";
+        return -1;
+    }
+    return OK;
+}
+
+status_t ObbVolume::doUnmount() {
+    auto path = getPath();
+
+    KillProcessesUsingPath(path);
+    ForceUnmount(path);
+    rmdir(path.c_str());
+
+    return OK;
+}
+
+}  // namespace vold
+}  // namespace android