FileMonitor.cpp

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/*
 * FileMonitor.cpp
 *
 * Copyright (C) 2011 IBR, TU Braunschweig
 *
 * Written-by: Johannes Morgenroth <morgenroth@ibr.cs.tu-bs.de>
 *
 * 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 "config.h"
#include "net/FileMonitor.h"
#include "core/BundleCore.h"
#include <ibrcommon/Logger.h>
#include <ibrcommon/data/ConfigFile.h>

#ifdef HAVE_SYS_INOTIFY_H
#include <sys/inotify.h>
#include <unistd.h>
#endif

namespace dtn
{
        namespace net
        {
                inotifysocket::inotifysocket()
                {
                }

                inotifysocket::~inotifysocket()
                {
                }

                void inotifysocket::up() throw (ibrcommon::socket_exception)
                {
                        if (_state != SOCKET_DOWN)
                                throw ibrcommon::socket_exception("socket is already up");

#ifdef HAVE_SYS_INOTIFY_H
                        // initialize fd
                        _fd = inotify_init();
#endif

                        _state = SOCKET_UP;
                }

                void inotifysocket::down() throw (ibrcommon::socket_exception)
                {
                        if (_state != SOCKET_UP)
                                throw ibrcommon::socket_exception("socket is not up");

#ifdef HAVE_SYS_INOTIFY_H
                        for (watch_map::iterator iter = _watch_map.begin(); iter != _watch_map.end(); ++iter)
                        {
                                const int wd = (*iter).first;
                                inotify_rm_watch(this->fd(), wd);
                        }
                        _watch_map.clear();

                        this->close();
#endif

                        _state = SOCKET_DOWN;
                }

                void inotifysocket::watch(const ibrcommon::File &path, int opts) throw (ibrcommon::socket_exception)
                {
#ifdef HAVE_SYS_INOTIFY_H
                        int wd = inotify_add_watch(this->fd(), path.getPath().c_str(), opts);
                        _watch_map[wd] = path;
#endif
                }

                ssize_t inotifysocket::read(char *data, size_t len) throw (ibrcommon::socket_exception)
                {
#ifdef HAVE_SYS_INOTIFY_H
                        return ::read(this->fd(), data, len);
#else
                        return 0;
#endif
                }

                FileMonitor::FileMonitor()
                 : _running(true)
                {
                }

                FileMonitor::~FileMonitor()
                {
                        join();
                }

                void FileMonitor::watch(const ibrcommon::File &watch)
                {
                        IBRCOMMON_LOGGER_DEBUG_TAG("FileMonitor", 5) << "watch on: " << watch.getPath() << IBRCOMMON_LOGGER_ENDL;

                        if (!watch.isDirectory())
                                throw ibrcommon::Exception("can not watch files, please specify a directory");

                        ibrcommon::socketset socks = _socket.getAll();
                        if (socks.size() == 0) return;
                        inotifysocket &sock = dynamic_cast<inotifysocket&>(**socks.begin());

#ifdef HAVE_SYS_INOTIFY_H
                        sock.watch(watch, IN_CREATE | IN_DELETE);
#endif
                        _watchset.insert(watch);
                }

                void FileMonitor::componentUp() throw ()
                {
                        // routine checked for throw() on 15.02.2013
                        try {
                                _socket.up();
                        } catch (const ibrcommon::socket_exception &ex) {
                                IBRCOMMON_LOGGER_TAG("FileMonitor", error) << ex.what() << IBRCOMMON_LOGGER_ENDL;
                        }
                }

                void FileMonitor::componentRun() throw ()
                {
#ifdef HAVE_SYS_INOTIFY_H
                        while (_running)
                        {
                                ibrcommon::socketset fds;

                                // scan for mounts
                                scan();

                                try {
                                        char buf[1024];

                                        // select on all bound sockets
                                        _socket.select(&fds, NULL, NULL, NULL);

                                        // receive from all sockets
                                        for (ibrcommon::socketset::iterator iter = fds.begin(); iter != fds.end(); ++iter)
                                        {
                                                inotifysocket &sock = dynamic_cast<inotifysocket&>(**iter);
                                                sock.read((char*)&buf, 1024);
                                        }

                                        ibrcommon::Thread::sleep(2000);
                                } catch (const ibrcommon::vsocket_interrupt&) {
                                        return;
                                } catch (const ibrcommon::vsocket_timeout&) {
                                        // scan again after timeout
                                } catch (const ibrcommon::socket_exception&) {
                                        return;
                                }
                        }
#endif
                }

                void FileMonitor::componentDown() throw ()
                {
                        _socket.down();
                }

                void FileMonitor::__cancellation() throw ()
                {
                        _socket.down();
                }

                void FileMonitor::scan()
                {
                        IBRCOMMON_LOGGER_DEBUG_TAG("FileMonitor", 5) << "scan for file changes" << IBRCOMMON_LOGGER_ENDL;

                        std::set<ibrcommon::File> watch_set;

                        for (watch_set::iterator iter = _watchset.begin(); iter != _watchset.end(); ++iter)
                        {
                                const ibrcommon::File &path = (*iter);
                                std::list<ibrcommon::File> files;

                                if (path.getFiles(files) == 0)
                                {
                                        for (std::list<ibrcommon::File>::iterator iter = files.begin(); iter != files.end(); ++iter)
                                        {
                                                watch_set.insert(*iter);
                                        }
                                }
                                else
                                {
                                        IBRCOMMON_LOGGER_TAG("FileMonitor", error) << "scan of " << path.getPath() << " failed" << IBRCOMMON_LOGGER_ENDL;
                                }
                        }

                        // check for new directories
                        for (std::set<ibrcommon::File>::iterator iter = watch_set.begin(); iter != watch_set.end(); ++iter)
                        {
                                const ibrcommon::File &path = (*iter);
                                if (path.isDirectory() && !path.isSystem())
                                {
                                        if (!isActive(path)) {
                                                adopt(path);
                                        }
                                }
                        }

                        // look for gone directories
                        for (std::map<ibrcommon::File, dtn::core::Node>::iterator iter = _active_paths.begin(); iter != _active_paths.end();)
                        {
                                const ibrcommon::File &path = (*iter).first;
                                const dtn::core::Node &node = (*iter).second;

                                if (watch_set.find(path) == watch_set.end())
                                {
                                        dtn::core::BundleCore::getInstance().getConnectionManager().remove(node);
                                        IBRCOMMON_LOGGER_DEBUG_TAG("FileMonitor", 5) << "Node on drive gone: " << node.getEID().getString() << IBRCOMMON_LOGGER_ENDL;
                                        _active_paths.erase(iter++);
                                }
                                else
                                {
                                        ++iter;
                                }
                        }
                }

                void FileMonitor::adopt(const ibrcommon::File &path)
                {
                        // look for ".dtndrive" file
                        const ibrcommon::File drivefile = path.get(".dtndrive");
                        if (drivefile.exists())
                        {
                                ibrcommon::ConfigFile cf(drivefile.getPath());

                                try {
                                        const dtn::data::EID eid( cf.read<std::string>("EID") );

                                        dtn::core::Node n(eid);
                                        const std::string uri = "file://" + path.getPath() + "/" + cf.read<std::string>("PATH");

                                        n.add(dtn::core::Node::URI(dtn::core::Node::NODE_DISCOVERED, dtn::core::Node::CONN_FILE, uri, 0));
                                        dtn::core::BundleCore::getInstance().getConnectionManager().add(n);

                                        _active_paths[path] = n;

                                        IBRCOMMON_LOGGER_DEBUG_TAG("FileMonitor", 5) << "Node on drive found: " << n.getEID().getString() << IBRCOMMON_LOGGER_ENDL;

                                } catch (const ibrcommon::ConfigFile::key_not_found&) {};
                        }
                }

                bool FileMonitor::isActive(const ibrcommon::File &path) const
                {
                        return (_active_paths.find(path) != _active_paths.end());
                }

                const std::string FileMonitor::getName() const
                {
                        return "FileMonitor";
                }
        }
} /* namespace ibrcommon */