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

#ifdef __cplusplus

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

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

#include "android/os/IVoldListener.h"

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

/* The length of an MD5 hash when encoded into ASCII hex characters */
#define MD5_ASCII_LENGTH_PLUS_NULL ((MD5_DIGEST_LENGTH*2)+1)

#define DEBUG_APPFUSE 0

typedef enum { ASEC, OBB } container_type_t;

class ContainerData {
public:
    ContainerData(char* _id, container_type_t _type)
            : id(_id)
            , type(_type)
    {}

    ~ContainerData() {
        if (id != NULL) {
            free(id);
            id = NULL;
        }
    }

    char *id;
    container_type_t type;
};

typedef android::List<ContainerData*> AsecIdCollection;

class VolumeManager {
public:
    static const char *SEC_ASECDIR_EXT;
    static const char *SEC_ASECDIR_INT;
    static const char *ASECDIR;
    static const char *LOOPDIR;

    //TODO remove this with better solution, b/64143519
    static bool shutting_down;

private:
    static VolumeManager *sInstance;

    SocketListener        *mBroadcaster;

    AsecIdCollection      *mActiveContainers;
    bool                   mDebug;

    // for adjusting /proc/sys/vm/dirty_ratio when UMS is active
    int                    mUmsSharingCount;
    int                    mSavedDirtyRatio;
    int                    mUmsDirtyRatio;

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);

    int onUserAdded(userid_t userId, int userSerialNumber);
    int onUserRemoved(userid_t userId);
    int onUserStarted(userid_t userId);
    int onUserStopped(userid_t userId);

    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();

    /* ASEC */
    int findAsec(const char *id, char *asecPath = NULL, size_t asecPathLen = 0,
            const char **directory = NULL) const;
    int createAsec(const char *id, unsigned long numSectors, const char *fstype,
                   const char *key, const int ownerUid, bool isExternal);
    int resizeAsec(const char *id, unsigned long numSectors, const char *key);
    int finalizeAsec(const char *id);

    /**
     * Fixes ASEC permissions on a filesystem that has owners and permissions.
     * This currently means EXT4-based ASEC containers.
     *
     * There is a single file that can be marked as "private" and will not have
     * world-readable permission. The group for that file will be set to the gid
     * supplied.
     *
     * Returns 0 on success.
     */
    int fixupAsecPermissions(const char *id, gid_t gid, const char* privateFilename);
    int destroyAsec(const char *id, bool force);
    int mountAsec(const char *id, const char *key, int ownerUid, bool readOnly);
    int unmountAsec(const char *id, bool force);
    int renameAsec(const char *id1, const char *id2);
    int getAsecMountPath(const char *id, char *buffer, int maxlen);
    int getAsecFilesystemPath(const char *id, char *buffer, int maxlen);

    /* Loopback images */
    int listMountedObbs(SocketClient* cli);
    int mountObb(const char *fileName, const char *key, int ownerUid);
    int unmountObb(const char *fileName, bool force);
    int getObbMountPath(const char *id, char *buffer, int maxlen);

    /* Shared between ASEC and Loopback images */
    int unmountLoopImage(const char *containerId, const char *loopId,
            const char *fileName, const char *mountPoint, bool force);

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

    void setBroadcaster(SocketListener *sl) { mBroadcaster = sl; }
    SocketListener *getBroadcaster() { return mBroadcaster; }

    static VolumeManager *Instance();

    static char *asecHash(const char *id, char *buffer, size_t len);

    /*
     * 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 char* 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();
    bool isMountpointMounted(const char *mp);
    bool isAsecInDirectory(const char *dir, const char *asec) const;
    bool isLegalAsecId(const char *id) const;

    int linkPrimary(userid_t userId);

    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::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;

    int mNextObbId;
};

extern "C" {
#endif /* __cplusplus */
#define UNMOUNT_NOT_MOUNTED_ERR (-2)
    int vold_unmountAll(void);
#ifdef __cplusplus
}
#endif

#endif