libreoffice-online/wsd/DocumentBroker.hpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
/*
* This file is part of the LibreOffice project.
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
#ifndef INCLUDED_DOCUMENTBROKER_HPP
#define INCLUDED_DOCUMENTBROKER_HPP
#include <csignal>
#include <atomic>
#include <chrono>
#include <condition_variable>
#include <deque>
#include <map>
#include <memory>
#include <mutex>
#include <string>
#include <thread>
#include <Poco/URI.h>
#include "IoUtil.hpp"
#include "Log.hpp"
#include "TileDesc.hpp"
#include "Util.hpp"
#include "net/Socket.hpp"
#include "net/WebSocketHandler.hpp"
#include "common/SigUtil.hpp"
// Forwards.
class PrisonerRequestDispatcher;
class DocumentBroker;
class StorageBase;
class TileCache;
class Message;
class TerminatingPoll : public SocketPoll
{
public:
TerminatingPoll(const std::string &threadName) :
SocketPoll(threadName) {}
bool continuePolling() override
{
return SocketPoll::continuePolling()
&& !TerminationFlag && !ShutdownRequestFlag;
}
};
/// Represents a new LOK child that is read
/// to host a document.
class ChildProcess
{
// FIXME: urk ...
friend class PrisonerRequestDispatcher;
public:
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/// @param pid is the process ID of the child.
/// @param socket is the underlying Sockeet to the child.
ChildProcess(const Poco::Process::PID pid, const std::shared_ptr<StreamSocket>& socket, const Poco::Net::HTTPRequest &request) :
_pid(pid),
_ws(std::make_shared<WebSocketHandler>(socket, request)),
_socket(socket)
{
LOG_INF("ChildProcess ctor [" << _pid << "].");
}
ChildProcess(ChildProcess&& other) = delete;
const ChildProcess& operator=(ChildProcess&& other) = delete;
~ChildProcess()
{
if (_pid > 0)
{
LOG_DBG("~ChildProcess dtor [" << _pid << "].");
close(true);
// No need for the socket anymore.
_ws.reset();
_socket.reset();
}
}
void setDocumentBroker(const std::shared_ptr<DocumentBroker>& docBroker);
void stop()
{
// FIXME: stop !?
LOG_ERR("What do we do for stop?");
try
{
if (isAlive())
{
LOG_DBG("Stopping ChildProcess [" << _pid << "]");
sendTextFrame("exit");
}
}
catch (const std::exception&)
{
// Already logged in sendTextFrame.
}
}
void close(const bool rude)
{
if (_pid < 0)
return;
try
{
LOG_DBG("Closing ChildProcess [" << _pid << "].");
// First mark to stop the thread so it knows it's intentional.
stop();
// Shutdown the socket to break the thread if blocked on it.
if (_ws)
_ws->shutdown();
}
catch (const std::exception& ex)
{
LOG_ERR("Error while closing child process: " << ex.what());
}
// Kill or abandon the child.
if (_pid != -1 && rude && kill(_pid, 0) != 0 && errno != ESRCH)
{
LOG_INF("Killing child [" << _pid << "].");
if (SigUtil::killChild(_pid))
{
LOG_ERR("Cannot terminate lokit [" << _pid << "]. Abandoning.");
}
}
_pid = -1;
}
Poco::Process::PID getPid() const { return _pid; }
/// Send a text payload to the child-process WS.
bool sendTextFrame(const std::string& data)
{
try
{
if (_ws)
{
LOG_TRC("DocBroker to Child: " << data);
_ws->sendFrame(data);
return true;
}
}
catch (const std::exception& exc)
{
LOG_ERR("Failed to send child [" << _pid << "] data [" <<
data << "] due to: " << exc.what());
throw;
}
LOG_WRN("No socket between DocBroker and child to send [" << data << "]");
return false;
}
/// Check whether this child is alive and socket not in error.
/// Note: zombies will show as alive, and sockets have waiting
/// time after the other end-point closes. So this isn't accurate.
bool isAlive() const
{
try
{
return _pid > 1 && _ws && kill(_pid, 0) == 0;
}
catch (const std::exception&)
{
}
return false;
}
private:
void socketProcessor();
private:
Poco::Process::PID _pid;
std::shared_ptr<WebSocketHandler> _ws;
std::shared_ptr<Socket> _socket;
std::weak_ptr<DocumentBroker> _docBroker;
};
class ClientSession;
/// DocumentBroker is responsible for setting up a document
/// in jail and brokering loading it from Storage
/// and saving it back.
/// Contains URI, physical path, etc.
class DocumentBroker : public std::enable_shared_from_this<DocumentBroker>
{
class DocumentBrokerPoll;
public:
static Poco::URI sanitizeURI(const std::string& uri);
/// Returns a document-specific key based
/// on the URI of the document.
static std::string getDocKey(const Poco::URI& uri);
/// Dummy document broker that is marked to destroy.
DocumentBroker();
/// Construct DocumentBroker with URI, docKey, and root path.
DocumentBroker(const std::string& uri,
const Poco::URI& uriPublic,
const std::string& docKey,
const std::string& childRoot);
~DocumentBroker();
/// Start processing events
void startThread();
/// Loads a document from the public URI into the jail.
bool load(std::shared_ptr<ClientSession>& session, const std::string& jailId);
bool isLoaded() const { return _isLoaded; }
void setLoaded();
/// Save the document to Storage if it needs persisting.
bool saveToStorage(const std::string& sesionId, bool success, const std::string& result = "");
bool isModified() const { return _isModified; }
void setModified(const bool value);
/// Save the document if the document is modified.
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/// @param force when true, will force saving if there
/// has been any recent activity after the last save.
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/// @return true if attempts to save or it also waits
/// and receives save notification. Otherwise, false.
bool autoSave(const bool force);
Poco::URI getPublicUri() const { return _uriPublic; }
Poco::URI getJailedUri() const { return _uriJailed; }
const std::string& getJailId() const { return _jailId; }
const std::string& getDocKey() const { return _docKey; }
const std::string& getFilename() const { return _filename; };
TileCache& tileCache() { return *_tileCache; }
bool isAlive() const;
size_t getSessionsCount() const
{
Util::assertIsLocked(_mutex);
return _sessions.size();
}
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void dumpState();
std::string getJailRoot() const;
/// Queue a new session to be added asynchronously.
/// @return amount of session we have after all the queued ones will be
/// created.
size_t queueSession(std::shared_ptr<ClientSession>& session);
/// Removes a session by ID. Returns the new number of sessions.
size_t removeSession(const std::string& id, bool destroyIfLast = false);
void addSocketToPoll(const std::shared_ptr<Socket>& socket);
void alertAllUsers(const std::string& msg);
void alertAllUsers(const std::string& cmd, const std::string& kind)
{
alertAllUsers("error: cmd=" + cmd + " kind=" + kind);
}
/// Invalidate the cursor position.
void invalidateCursor(int x, int y, int w, int h)
{
_cursorPosX = x;
_cursorPosY = y;
_cursorWidth = w;
_cursorHeight = h;
}
void invalidateTiles(const std::string& tiles);
void handleTileRequest(TileDesc& tile,
const std::shared_ptr<ClientSession>& session);
void handleTileCombinedRequest(TileCombined& tileCombined,
const std::shared_ptr<ClientSession>& session);
void cancelTileRequests(const std::shared_ptr<ClientSession>& session);
void handleTileResponse(const std::vector<char>& payload);
void handleTileCombinedResponse(const std::vector<char>& payload);
void destroyIfLastEditor(const std::string& id);
bool isMarkedToDestroy() const { return _markToDestroy; }
bool handleInput(const std::vector<char>& payload);
/// Forward a message from client session to its respective child session.
bool forwardToChild(const std::string& viewId, const std::string& message);
int getRenderedTileCount() { return _debugRenderedTileCount; }
void closeDocument(const std::string& reason);
/// Called by the ChildProcess object to notify
/// that it has terminated on its own.
/// This happens either when the child exists
/// or upon failing to process an incoming message.
void childSocketTerminated();
/// This gracefully terminates the connection
/// with the child and cleans up ChildProcess etc.
/// We must be called under lock and it must be
/// passed to us so we unlock before waiting on
/// the ChildProcess thread, which can take our lock.
void terminateChild(std::unique_lock<std::mutex>& lock, const std::string& closeReason);
/// Get the PID of the associated child process
Poco::Process::PID getPid() const { return _childProcess->getPid(); }
std::unique_lock<std::mutex> getLock() { return std::unique_lock<std::mutex>(_mutex); }
std::unique_lock<std::mutex> getDeferredLock() { return std::unique_lock<std::mutex>(_mutex, std::defer_lock); }
void updateLastActivityTime();
std::size_t getIdleTimeSecs() const
{
const auto duration = (std::chrono::steady_clock::now() - _lastActivityTime);
return std::chrono::duration_cast<std::chrono::seconds>(duration).count();
}
private:
/// Sends the .uno:Save command to LoKit.
bool sendUnoSave(const bool dontSaveIfUnmodified);
/// Saves the doc to the storage.
bool saveToStorageInternal(const std::string& sesionId, bool success, const std::string& result = "");
/// Removes a session by ID. Returns the new number of sessions.
size_t removeSessionInternal(const std::string& id);
/// Forward a message from child session to its respective client session.
bool forwardToClient(const std::shared_ptr<Message>& payload);
/// Add a new session. Returns the new number of sessions.
size_t addSession(std::shared_ptr<ClientSession>& session);
/// The thread function that all of the I/O for all sessions
/// associated with this document.
void pollThread();
private:
const std::string _uriOrig;
const Poco::URI _uriPublic;
const std::string _docKey;
const std::string _childRoot;
const std::string _cacheRoot;
std::shared_ptr<ChildProcess> _childProcess;
Poco::URI _uriJailed;
std::string _jailId;
std::string _filename;
/// The last time we tried saving, regardless of whether the
/// document was modified and saved or not.
std::chrono::steady_clock::time_point _lastSaveTime;
/// The document's last-modified time on storage.
WIP: Check if the document has been modified behind our back For now, do the check only when a new session connects to the document, because at that point we fetch the document information (in separate function for WOPI and local files) and construct the FileInfo, including timestamp. For now, just log an ERR message if we notice that the document in its storage system (WOPI or local file system) has an unexpected last modified time. What should we do? If we don't have unsaved changes, most likely we should just silently reload the document and force all sessions to refresh. But if we have unsaved changes, and the document has changed underneath, we have a problem. We need to fetch the timestamp also also after saving ("persisting") as we can't assume that the clock on the machine running loolwsd and that of the storage (as reported in the WOPI case in CheckFileInfo) are in synch. (Assuming separate machines, they certainly won't ever exactly in synch, but aren't necessarily even just a few seconds apart (think incorrectly set up timezone etc), so no amount of tolerance in the comparison would be good enough, because after all, it might be that in the problematic cases we are looking for the timestamps also are separated by a quite short time.) Yes, this means there is a race condition; what if the document is modified behind out back right after we have persisted it, before we ask for its timestamp? It would be much better if the persisting operation atomically also told what the timestamp of the document in the storage is after persisting, but alas, WOPI doesn't do that. Rename the DocumentBroker::origDocumentLastModifiedTime field to _documentLastModifiedTime as that is less misleading. It is not the "original" document timestamp but the timestamp of the document in its storage system. This needs much more work: Ideally the timestamp of the document in its storage system should be retrieved and checked against the expected value also before we are about to save it. But unfortunately experience has shown that the WOPI CheckFileInfo operation can be expensive, so we'll see what can be done. Ideally WOPI should contain the optional functionality to return an error if, when saving a document, its timestamp (and size?) in storage are not what the saving client expects. Also add a few FIXME comments. Change-Id: I5a9b55d4b55a8db0c9ee8638edd368dc0aa325d5
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Poco::Timestamp _documentLastModifiedTime;
/// The jailed file last-modified time.
Poco::Timestamp _lastFileModifiedTime;
std::map<std::string, std::shared_ptr<ClientSession> > _sessions;
/// Private class to remember what sessions we have to create, and what
/// messages to send to them after they are really created.
class NewSession {
public:
NewSession(const std::shared_ptr<ClientSession>& session) : _session(session)
{
}
std::shared_ptr<ClientSession> _session;
std::deque<std::string> _messages;
};
/// Sessions that are queued for addition.
std::deque<NewSession> _newSessions;
std::unique_ptr<StorageBase> _storage;
std::unique_ptr<TileCache> _tileCache;
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std::atomic<bool> _markToDestroy;
std::atomic<bool> _lastEditableSession;
std::atomic<bool> _isLoaded;
std::atomic<bool> _isModified;
int _cursorPosX;
int _cursorPosY;
int _cursorWidth;
int _cursorHeight;
mutable std::mutex _mutex;
std::unique_ptr<DocumentBrokerPoll> _poll;
std::atomic<bool> _stop;
/// Versioning is used to prevent races between
/// painting and invalidation.
std::atomic<size_t> _tileVersion;
int _debugRenderedTileCount;
std::chrono::steady_clock::time_point _lastActivityTime;
std::chrono::steady_clock::time_point _threadStart;
std::chrono::milliseconds _loadDuration;
static constexpr auto IdleSaveDurationMs = 30 * 1000;
static constexpr auto AutoSaveDurationMs = 300 * 1000;
};
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */