Package org.jnode.fs.service.def

Source Code of org.jnode.fs.service.def.FileSystemMounter

/*
* $Id$
*
* Copyright (C) 2003-2014 JNode.org
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; If not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
package org.jnode.fs.service.def;

import java.io.File;
import java.io.IOException;
import java.nio.ByteBuffer;

import javax.naming.NameNotFoundException;

import org.apache.log4j.Logger;
import org.jnode.driver.ApiNotFoundException;
import org.jnode.driver.Device;
import org.jnode.driver.DeviceListener;
import org.jnode.driver.DeviceManager;
import org.jnode.driver.RemovableDeviceAPI;
import org.jnode.driver.block.FSBlockDeviceAPI;
import org.jnode.fs.FileSystem;
import org.jnode.fs.FileSystemException;
import org.jnode.fs.FileSystemType;
import org.jnode.fs.BlockDeviceFileSystemType;
import org.jnode.fs.service.FileSystemService;
import org.jnode.naming.InitialNaming;
import org.jnode.partitions.PartitionTableEntry;
import org.jnode.plugin.PluginException;
import org.jnode.work.Work;
import org.jnode.work.WorkUtils;

/**
* A FileSystemMounter listens to the DeviceManager and once a Device that
* implements the BlockDeviceAPI is started, it tries to mount a FileSystem on
* that device.
*
* @author epr
*/
final class FileSystemMounter implements DeviceListener {

    /** My logger */
    private static final Logger log = Logger.getLogger(FileSystemMounter.class);

    private static final String MOUNT_ROOT = "devices";

    /** The DeviceManager i'm listening to */
    private DeviceManager devMan;

    /** The FileSystemService i'm using */
    private final FileSystemService fileSystemService;

    public FileSystemMounter(FileSystemService fileSystemService) {
        this.fileSystemService = fileSystemService;
    }

    /**
     * Start the FS mounter.
     *
     * @throws PluginException
     */
    public void start() throws PluginException {
        try {
            // Create the /devices
            fileSystemService.getApi().mkDir(MOUNT_ROOT);

            devMan = InitialNaming.lookup(DeviceManager.NAME);
            devMan.addListener(this);
        } catch (NameNotFoundException ex) {
            throw new PluginException("Cannot find DeviceManager", ex);
        } catch (IOException ex) {
            throw new PluginException("Cannot create devices directory");
        }

    }

    /**
     * Stop the FS mounter.
     */
    public void stop() {
        devMan.removeListener(this);
    }

    /**
     * @see org.jnode.driver.DeviceListener#deviceStarted(org.jnode.driver.Device)
     */
    public final void deviceStarted(final Device device) {
        if (device.implementsAPI(FSBlockDeviceAPI.class)) {
            // add it to the queue of devices to be mounted only if the action
            // is not already pending
            WorkUtils.add(new Work("Mounting " + device.getId()) {
                public void execute() {
                    asyncDeviceStarted(device);
                }
            });
        }
    }

    /**
     * @see org.jnode.driver.DeviceListener#deviceStop(org.jnode.driver.Device)
     */
    public final void deviceStop(Device device) {
        if (device.implementsAPI(FSBlockDeviceAPI.class)) {
            final FileSystem<?> fs = fileSystemService.unregisterFileSystem(device);
            if (fs != null) {
                try {
                    fs.close();
                } catch (IOException ex) {
                    log.error("Cannot close filesystem", ex);
                }
            }
        }
    }

    /**
     * Try to mount a filesystem on the given device.
     *
     * @param device
     * @param api
     */
    protected void tryToMount(Device device, FSBlockDeviceAPI api, boolean removable,
            boolean readOnly) {
        if (fileSystemService.getFileSystem(device) != null) {
            log.info("device already mounted...");
            return;
        }

        // if (removable) {
        // log.error("Not mounting removable devices yet...");
        // TODO Implement mounting of removable devices
        // return;
        // }

        log.info("Try to mount " + device.getId());
        // Read the first sector
        try {
            final PartitionTableEntry ptEntry = api.getPartitionTableEntry();
            final ByteBuffer bs = ByteBuffer.allocate(api.getSectorSize());
            final String mountPath = File.separatorChar + MOUNT_ROOT + File.separatorChar;

            api.read(0, bs);
            for (FileSystemType<?> fst : fileSystemService.fileSystemTypes()) {
                if (fst instanceof BlockDeviceFileSystemType) {
                    if (((BlockDeviceFileSystemType<?>) fst).supports(ptEntry, bs.array(), api)) {
                        try {
                            final FileSystem<?> fs = fst.create(device, readOnly);
                            fileSystemService.registerFileSystem(fs);

                            final String fullPath = mountPath + device.getId();
                            log.debug("Mounting " + device.getId() + " on " + fullPath);
                            fileSystemService.mount(fullPath, fs, null);

                            log.info("Mounted " + fst.getName() + " on " + fullPath);
                            return;
                        } catch (FileSystemException ex) {
                            log.error("Cannot mount " + fst.getName() + " filesystem on " +
                                    device.getId(), ex);
                        } catch (IOException ex) {
                            log.error("Cannot mount " + fst.getName() + " filesystem on " +
                                    device.getId(), ex);
                        }
                    }
                }
            }
            log.info("No filesystem found for " + device.getId());
        } catch (IOException ex) {
            log.error("Cannot read bootsector of " + device.getId());
        }
    }

    /**
     * Mount the filesystem on the given device.
     */
    final void asyncDeviceStarted(Device device) {
        try {
            if (device.isStarted()) {
                final FSBlockDeviceAPI api = device.getAPI(FSBlockDeviceAPI.class);
                final boolean readOnly = false; // TODO: read from config
                if (device.implementsAPI(RemovableDeviceAPI.class)) {
                    tryToMount(device, api, true, readOnly);
                } else {
                    tryToMount(device, api, false, readOnly);
                }
            }
        } catch (ApiNotFoundException ex) {
            // Just ignore this device.
        }
    }
}
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