VolumeManager.h

/*
 * 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_MANAGER_H
#define ANDROID_VOLD_VOLUME_MANAGER_H

#include <fnmatch.h>
#include <pthread.h>
#include <stdlib.h>

#include <list>
#include <mutex>
#include <string>
#include <unordered_map>
#include <unordered_set>

#include <android-base/unique_fd.h>
#include <cutils/multiuser.h>
#include <sysutils/NetlinkEvent.h>
#include <utils/List.h>
#include <utils/Timers.h>

#include "android/os/IVoldListener.h"

#include "model/Disk.h"
#include "model/VolumeBase.h"

#define DEBUG_APPFUSE 0

class VolumeManager {
  private:
    static VolumeManager* sInstance;

    bool mDebug;

  public:
    virtual ~VolumeManager();

    // TODO: pipe all requests through VM to avoid exposing this lock
    std::mutex& getLock() { return mLock; }
    std::mutex& getCryptLock() { return mCryptLock; }

    void setListener(android::sp<android::os::IVoldListener> listener) { mListener = listener; }
    android::sp<android::os::IVoldListener> getListener() { return mListener; }

    int start();
    int stop();

    void handleBlockEvent(NetlinkEvent* evt);

    class DiskSource {
      public:
        DiskSource(const std::string& sysPattern, const std::string& nickname, int flags)
            : mSysPattern(sysPattern), mNickname(nickname), mFlags(flags) {}

        bool matches(const std::string& sysPath) {
            return !fnmatch(mSysPattern.c_str(), sysPath.c_str(), 0);
        }

        const std::string& getNickname() { return mNickname; }
        int getFlags() { return mFlags; }

      private:
        std::string mSysPattern;
        std::string mNickname;
        int mFlags;
    };

    void addDiskSource(const std::shared_ptr<DiskSource>& diskSource);

    std::shared_ptr<android::vold::Disk> findDisk(const std::string& id);
    std::shared_ptr<android::vold::VolumeBase> findVolume(const std::string& id);

    void listVolumes(android::vold::VolumeBase::Type type, std::list<std::string>& list);

    int forgetPartition(const std::string& partGuid, const std::string& fsUuid);

    int onUserAdded(userid_t userId, int userSerialNumber);
    int onUserRemoved(userid_t userId);
    int onUserStarted(userid_t userId, const std::vector<std::string>& packageNames);
    int onUserStopped(userid_t userId);

    int addAppIds(const std::vector<std::string>& packageNames, const std::vector<int32_t>& appIds);
    int addSandboxIds(const std::vector<int32_t>& appIds,
                      const std::vector<std::string>& sandboxIds);
    int mountExternalStorageForApp(const std::string& packageName, appid_t appId,
                                   const std::string& sandboxId, userid_t userId);

    int onVolumeMounted(android::vold::VolumeBase* vol);
    int onVolumeUnmounted(android::vold::VolumeBase* vol);

    int onSecureKeyguardStateChanged(bool isShowing);

    int setPrimary(const std::shared_ptr<android::vold::VolumeBase>& vol);

    int remountUid(uid_t uid, const std::string& mode);

    /* Reset all internal state, typically during framework boot */
    int reset();
    /* Prepare for device shutdown, safely unmounting all devices */
    int shutdown();
    /* Unmount all volumes, usually for encryption */
    int unmountAll();

    int updateVirtualDisk();
    int setDebug(bool enable);

    static VolumeManager* Instance();

    /*
     * Ensure that all directories along given path exist, creating parent
     * directories as needed.  Validates that given path is absolute and that
     * it contains no relative "." or ".." paths or symlinks.  Last path segment
     * is treated as filename and ignored, unless the path ends with "/".  Also
     * ensures that path belongs to a volume managed by vold.
     */
    int mkdirs(const std::string& path);

    int createObb(const std::string& path, const std::string& key, int32_t ownerGid,
                  std::string* outVolId);
    int destroyObb(const std::string& volId);

    int mountAppFuse(uid_t uid, pid_t pid, int mountId, android::base::unique_fd* device_fd);
    int unmountAppFuse(uid_t uid, pid_t pid, int mountId);

  private:
    VolumeManager();
    void readInitialState();

    int linkPrimary(userid_t userId);

    int prepareSandboxes(userid_t userId, const std::vector<std::string>& packageNames,
                         const std::vector<std::string>& visibleVolLabels);
    int mountPkgSpecificDirsForRunningProcs(userid_t userId,
                                            const std::vector<std::string>& packageNames,
                                            const std::vector<std::string>& visibleVolLabels);
    int destroySandboxesForVol(android::vold::VolumeBase* vol, userid_t userId);
    std::string prepareSandboxSource(uid_t uid, const std::string& sandboxId,
                                     const std::string& sandboxRootDir);
    std::string prepareSandboxTarget(const std::string& packageName, uid_t uid,
                                     const std::string& volumeLabel,
                                     const std::string& mntTargetRootDir, bool isUserDependent);
    std::string preparePkgDataSource(const std::string& packageName, uid_t uid,
                                     const std::string& dataRootDir);
    std::string prepareSubDirs(const std::string& pathPrefix, const std::string& subDirs,
                               mode_t mode, uid_t uid, gid_t gid);
    bool createPkgSpecificDirRoots(const std::string& volumeRoot);
    bool createPkgSpecificDirs(const std::string& packageName, uid_t uid,
                               const std::string& volumeRoot, const std::string& sandboxDirRoot);
    int mountPkgSpecificDir(const std::string& mntSourceRoot, const std::string& mntTargetRoot,
                            const std::string& packageName, const char* dirName);

    void handleDiskAdded(const std::shared_ptr<android::vold::Disk>& disk);
    void handleDiskChanged(dev_t device);
    void handleDiskRemoved(dev_t device);

    std::mutex mLock;
    std::mutex mCryptLock;

    android::sp<android::os::IVoldListener> mListener;

    std::list<std::shared_ptr<DiskSource>> mDiskSources;
    std::list<std::shared_ptr<android::vold::Disk>> mDisks;
    std::list<std::shared_ptr<android::vold::Disk>> mPendingDisks;
    std::list<std::shared_ptr<android::vold::VolumeBase>> mObbVolumes;

    std::unordered_map<userid_t, int> mAddedUsers;
    std::unordered_set<userid_t> mStartedUsers;

    std::string mVirtualDiskPath;
    std::shared_ptr<android::vold::Disk> mVirtualDisk;
    std::shared_ptr<android::vold::VolumeBase> mInternalEmulated;
    std::shared_ptr<android::vold::VolumeBase> mPrimary;

    std::unordered_map<std::string, appid_t> mAppIds;
    std::unordered_map<appid_t, std::string> mSandboxIds;
    std::unordered_map<userid_t, std::vector<std::string>> mUserPackages;
    std::unordered_set<std::string> mVisibleVolumeIds;

    int mNextObbId;
    bool mSecureKeyguardShowing;
};

#endif