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/*
* Copyright (C) 2003-2015 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_NFS_CONNECTION_HXX
#define MPD_NFS_CONNECTION_HXX
#include "Lease.hxx"
#include "Cancellable.hxx"
#include "event/SocketMonitor.hxx"
#include "event/TimeoutMonitor.hxx"
#include "event/DeferredMonitor.hxx"
#include "util/Error.hxx"
#include <boost/intrusive/list.hpp>
#include <string>
#include <list>
#include <forward_list>
struct nfs_context;
struct nfsdir;
struct nfsdirent;
class NfsCallback;
/**
* An asynchronous connection to a NFS server.
*/
class NfsConnection : SocketMonitor, TimeoutMonitor, DeferredMonitor {
class CancellableCallback : public CancellablePointer<NfsCallback> {
NfsConnection &connection;
/**
* Is this a nfs_open_async() operation? If yes, then
* we need to call nfs_close_async() on the new file
* handle as soon as the callback is invoked
* successfully.
*/
const bool open;
/**
* The file handle scheduled to be closed as soon as
* the operation finishes.
*/
struct nfsfh *close_fh;
public:
explicit CancellableCallback(NfsCallback &_callback,
NfsConnection &_connection,
bool _open)
:CancellablePointer<NfsCallback>(_callback),
connection(_connection),
open(_open), close_fh(nullptr) {}
bool Stat(nfs_context *context, const char *path,
Error &error);
bool OpenDirectory(nfs_context *context, const char *path,
Error &error);
bool Open(nfs_context *context, const char *path, int flags,
Error &error);
bool Stat(nfs_context *context, struct nfsfh *fh,
Error &error);
bool Read(nfs_context *context, struct nfsfh *fh,
uint64_t offset, size_t size,
Error &error);
/**
* Cancel the operation and schedule a call to
* nfs_close_async() with the given file handle.
*/
void CancelAndScheduleClose(struct nfsfh *fh);
/**
* Called by NfsConnection::DestroyContext() right
* before nfs_destroy_context(). This object is given
* a chance to prepare for the latter.
*/
void PrepareDestroyContext();
private:
static void Callback(int err, struct nfs_context *nfs,
void *data, void *private_data);
void Callback(int err, void *data);
};
std::string server, export_name;
nfs_context *context;
typedef std::list<NfsLease *> LeaseList;
LeaseList new_leases, active_leases;
typedef CancellableList<NfsCallback, CancellableCallback> CallbackList;
CallbackList callbacks;
/**
* A list of NFS file handles (struct nfsfh *) which shall be
* closed as soon as nfs_service() returns. If we close the
* file handle while in nfs_service(), libnfs may crash, and
* deferring this call to after nfs_service() avoids this
* problem.
*/
std::forward_list<struct nfsfh *> deferred_close;
Error postponed_mount_error;
#ifndef NDEBUG
/**
* True when nfs_service() is being called.
*/
bool in_service;
/**
* True when OnSocketReady() is being called. During that,
* event updates are omitted.
*/
bool in_event;
/**
* True when DestroyContext() is being called.
*/
bool in_destroy;
#endif
bool mount_finished;
public:
gcc_nonnull_all
NfsConnection(EventLoop &_loop,
const char *_server, const char *_export_name)
:SocketMonitor(_loop), TimeoutMonitor(_loop),
DeferredMonitor(_loop),
server(_server), export_name(_export_name),
context(nullptr) {}
/**
* Must be run from EventLoop's thread.
*/
~NfsConnection();
gcc_pure
const char *GetServer() const {
return server.c_str();
}
gcc_pure
const char *GetExportName() const {
return export_name.c_str();
}
EventLoop &GetEventLoop() {
return SocketMonitor::GetEventLoop();
}
/**
* Ensure that the connection is established. The connection
* is kept up while at least one #NfsLease is registered.
*
* This method is thread-safe. However, #NfsLease's methods
* will be invoked from within the #EventLoop's thread.
*/
void AddLease(NfsLease &lease);
void RemoveLease(NfsLease &lease);
bool Stat(const char *path, NfsCallback &callback, Error &error);
bool OpenDirectory(const char *path, NfsCallback &callback,
Error &error);
const struct nfsdirent *ReadDirectory(struct nfsdir *dir);
void CloseDirectory(struct nfsdir *dir);
bool Open(const char *path, int flags, NfsCallback &callback,
Error &error);
bool Stat(struct nfsfh *fh, NfsCallback &callback, Error &error);
bool Read(struct nfsfh *fh, uint64_t offset, size_t size,
NfsCallback &callback, Error &error);
void Cancel(NfsCallback &callback);
void Close(struct nfsfh *fh);
void CancelAndClose(struct nfsfh *fh, NfsCallback &callback);
protected:
virtual void OnNfsConnectionError(Error &&error) = 0;
private:
void DestroyContext();
/**
* Wrapper for nfs_close_async().
*/
void InternalClose(struct nfsfh *fh);
/**
* Invoke nfs_close_async() after nfs_service() returns.
*/
void DeferClose(struct nfsfh *fh);
bool MountInternal(Error &error);
void BroadcastMountSuccess();
void BroadcastMountError(Error &&error);
void BroadcastError(Error &&error);
static void MountCallback(int status, nfs_context *nfs, void *data,
void *private_data);
void MountCallback(int status, nfs_context *nfs, void *data);
void ScheduleSocket();
/**
* Wrapper for nfs_service().
*/
int Service(unsigned flags);
/* virtual methods from SocketMonitor */
virtual bool OnSocketReady(unsigned flags) override;
/* virtual methods from TimeoutMonitor */
void OnTimeout() final;
/* virtual methods from DeferredMonitor */
virtual void RunDeferred() override;
};
#endif
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