libvirt/src/rpc/virnetclient.h
Michal Privoznik 833b901cb7 stream: Check for stream EOF
If client stream does not have any data to sink and neither received
EOF, a dummy packet is sent to the daemon signalising client is ready to
sink some data. However, after we added event loop to client a race may
occur:

Thread 1 calls virNetClientStreamRecvPacket and since no data are cached
nor stream has EOF, it decides to send dummy packet to server which will
sent some data in turn. However, during this decision and actual message
exchange with server -

Thread 2 receives last stream data from server. Therefore an EOF is set
on stream and if there is a call waiting (which is not yet) it is woken
up. However, Thread 1 haven't sent anything so far, so there is no call
to be woken up. So this thread sent dummy packet to daemon, which
ignores that as no stream is associated with such packet and therefore
no reply will ever come.

This race causes client to hang indefinitely.
2012-01-12 12:02:40 +01:00

108 lines
3.8 KiB
C

/*
* virnetclient.h: generic network RPC client
*
* Copyright (C) 2006-2011 Red Hat, Inc.
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#ifndef __VIR_NET_CLIENT_H__
# define __VIR_NET_CLIENT_H__
# include "virnettlscontext.h"
# include "virnetmessage.h"
# ifdef HAVE_SASL
# include "virnetsaslcontext.h"
# endif
# include "virnetclientprogram.h"
# include "virnetclientstream.h"
virNetClientPtr virNetClientNewUNIX(const char *path,
bool spawnDaemon,
const char *daemon);
virNetClientPtr virNetClientNewTCP(const char *nodename,
const char *service);
virNetClientPtr virNetClientNewSSH(const char *nodename,
const char *service,
const char *binary,
const char *username,
bool noTTY,
bool noVerify,
const char *netcat,
const char *keyfile,
const char *path);
virNetClientPtr virNetClientNewExternal(const char **cmdargv);
void virNetClientRef(virNetClientPtr client);
int virNetClientGetFD(virNetClientPtr client);
int virNetClientDupFD(virNetClientPtr client, bool cloexec);
bool virNetClientHasPassFD(virNetClientPtr client);
int virNetClientAddProgram(virNetClientPtr client,
virNetClientProgramPtr prog);
int virNetClientAddStream(virNetClientPtr client,
virNetClientStreamPtr st);
void virNetClientRemoveStream(virNetClientPtr client,
virNetClientStreamPtr st);
int virNetClientSendWithReply(virNetClientPtr client,
virNetMessagePtr msg);
int virNetClientSendNoReply(virNetClientPtr client,
virNetMessagePtr msg);
int virNetClientSendNonBlock(virNetClientPtr client,
virNetMessagePtr msg);
int virNetClientSendWithReplyStream(virNetClientPtr client,
virNetMessagePtr msg,
virNetClientStreamPtr st);
# ifdef HAVE_SASL
void virNetClientSetSASLSession(virNetClientPtr client,
virNetSASLSessionPtr sasl);
# endif
int virNetClientSetTLSSession(virNetClientPtr client,
virNetTLSContextPtr tls);
bool virNetClientIsEncrypted(virNetClientPtr client);
bool virNetClientIsOpen(virNetClientPtr client);
const char *virNetClientLocalAddrString(virNetClientPtr client);
const char *virNetClientRemoteAddrString(virNetClientPtr client);
int virNetClientGetTLSKeySize(virNetClientPtr client);
void virNetClientFree(virNetClientPtr client);
void virNetClientClose(virNetClientPtr client);
bool virNetClientKeepAliveIsSupported(virNetClientPtr client);
int virNetClientKeepAliveStart(virNetClientPtr client,
int interval,
unsigned int count);
#endif /* __VIR_NET_CLIENT_H__ */