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libvirt/daemon/stream.c

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/*
* stream.c: APIs for managing client streams
*
* Copyright (C) 2009-2014 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, see
* <http://www.gnu.org/licenses/>.
*
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include "stream.h"
#include "remote.h"
#include "viralloc.h"
#include "virlog.h"
#include "virnetserverclient.h"
#include "virerror.h"
#define VIR_FROM_THIS VIR_FROM_STREAMS
VIR_LOG_INIT("daemon.stream");
struct daemonClientStream {
daemonClientPrivatePtr priv;
int refs;
virNetServerProgramPtr prog;
virStreamPtr st;
int procedure;
unsigned int serial;
bool recvEOF;
bool closed;
int filterID;
virNetMessagePtr rx;
bool tx;
daemonClientStreamPtr next;
};
static int
daemonStreamHandleWrite(virNetServerClientPtr client,
daemonClientStream *stream);
static int
daemonStreamHandleRead(virNetServerClientPtr client,
daemonClientStream *stream);
static int
daemonStreamHandleFinish(virNetServerClientPtr client,
daemonClientStream *stream,
virNetMessagePtr msg);
static int
daemonStreamHandleAbort(virNetServerClientPtr client,
daemonClientStream *stream,
virNetMessagePtr msg);
static void
daemonStreamUpdateEvents(daemonClientStream *stream)
{
int newEvents = 0;
if (stream->closed)
return;
if (stream->rx)
newEvents |= VIR_STREAM_EVENT_WRITABLE;
if (stream->tx && !stream->recvEOF)
newEvents |= VIR_STREAM_EVENT_READABLE;
virStreamEventUpdateCallback(stream->st, newEvents);
}
/*
* Invoked when an outgoing data packet message has been fully sent.
* This simply re-enables TX of further data.
*
* The idea is to stop the daemon growing without bound due to
* fast stream, but slow client
*/
static void
daemonStreamMessageFinished(virNetMessagePtr msg,
void *opaque)
{
daemonClientStream *stream = opaque;
VIR_DEBUG("stream=%p proc=%d serial=%u",
stream, msg->header.proc, msg->header.serial);
stream->tx = true;
daemonStreamUpdateEvents(stream);
daemonFreeClientStream(NULL, stream);
}
/*
* Callback that gets invoked when a stream becomes writable/readable
*/
static void
daemonStreamEvent(virStreamPtr st, int events, void *opaque)
{
virNetServerClientPtr client = opaque;
daemonClientStream *stream;
daemonClientPrivatePtr priv = virNetServerClientGetPrivateData(client);
virMutexLock(&priv->lock);
stream = priv->streams;
while (stream) {
if (stream->st == st)
break;
stream = stream->next;
}
if (!stream) {
VIR_WARN("event for client=%p stream st=%p, but missing stream state", client, st);
virStreamEventRemoveCallback(st);
goto cleanup;
}
VIR_DEBUG("st=%p events=%d EOF=%d closed=%d", st, events, stream->recvEOF, stream->closed);
if (!stream->closed &&
(events & VIR_STREAM_EVENT_WRITABLE)) {
if (daemonStreamHandleWrite(client, stream) < 0) {
daemonRemoveClientStream(client, stream);
virNetServerClientClose(client);
goto cleanup;
}
}
if (!stream->closed && !stream->recvEOF &&
(events & (VIR_STREAM_EVENT_READABLE))) {
events = events & ~(VIR_STREAM_EVENT_READABLE);
if (daemonStreamHandleRead(client, stream) < 0) {
daemonRemoveClientStream(client, stream);
virNetServerClientClose(client);
goto cleanup;
}
/* If we detected EOF during read processing,
* then clear hangup/error conditions, since
* we want the client to see the EOF message
* we just sent them
*/
if (stream->recvEOF)
events = events & ~(VIR_STREAM_EVENT_HANGUP |
VIR_STREAM_EVENT_ERROR);
}
/* If we have a completion/abort message, always process it */
if (stream->rx) {
virNetMessagePtr msg = stream->rx;
switch (msg->header.status) {
case VIR_NET_CONTINUE:
/* nada */
break;
case VIR_NET_OK:
virNetMessageQueueServe(&stream->rx);
if (daemonStreamHandleFinish(client, stream, msg) < 0) {
virNetMessageFree(msg);
daemonRemoveClientStream(client, stream);
virNetServerClientClose(client);
goto cleanup;
}
break;
case VIR_NET_ERROR:
default:
virNetMessageQueueServe(&stream->rx);
if (daemonStreamHandleAbort(client, stream, msg) < 0) {
virNetMessageFree(msg);
daemonRemoveClientStream(client, stream);
virNetServerClientClose(client);
goto cleanup;
}
break;
}
}
/* If we got HANGUP, we need to only send an empty
* packet so the client sees an EOF and cleans up
*/
if (!stream->closed && !stream->recvEOF &&
(events & VIR_STREAM_EVENT_HANGUP)) {
virNetMessagePtr msg;
events &= ~(VIR_STREAM_EVENT_HANGUP);
stream->tx = false;
stream->recvEOF = true;
if (!(msg = virNetMessageNew(false))) {
daemonRemoveClientStream(client, stream);
virNetServerClientClose(client);
goto cleanup;
}
msg->cb = daemonStreamMessageFinished;
msg->opaque = stream;
stream->refs++;
if (virNetServerProgramSendStreamData(remoteProgram,
client,
msg,
stream->procedure,
stream->serial,
"", 0) < 0) {
virNetMessageFree(msg);
daemonRemoveClientStream(client, stream);
virNetServerClientClose(client);
goto cleanup;
}
}
if (!stream->closed &&
(events & (VIR_STREAM_EVENT_ERROR | VIR_STREAM_EVENT_HANGUP))) {
int ret;
virNetMessagePtr msg;
virNetMessageError rerr;
memset(&rerr, 0, sizeof(rerr));
stream->closed = true;
virStreamEventRemoveCallback(stream->st);
virStreamAbort(stream->st);
if (events & VIR_STREAM_EVENT_HANGUP)
virReportError(VIR_ERR_RPC,
"%s", _("stream had unexpected termination"));
else
virReportError(VIR_ERR_RPC,
"%s", _("stream had I/O failure"));
msg = virNetMessageNew(false);
if (!msg) {
ret = -1;
} else {
ret = virNetServerProgramSendStreamError(remoteProgram,
client,
msg,
&rerr,
stream->procedure,
stream->serial);
}
daemonRemoveClientStream(client, stream);
if (ret < 0)
virNetServerClientClose(client);
goto cleanup;
}
if (stream->closed) {
daemonRemoveClientStream(client, stream);
} else {
daemonStreamUpdateEvents(stream);
}
cleanup:
virMutexUnlock(&priv->lock);
}
/*
* @client: a locked client object
*
* Invoked by the main loop when filtering incoming messages.
*
* Returns 1 if the message was processed, 0 if skipped,
* -1 on fatal client error
*/
static int
daemonStreamFilter(virNetServerClientPtr client ATTRIBUTE_UNUSED,
virNetMessagePtr msg,
void *opaque)
{
daemonClientStream *stream = opaque;
int ret = 0;
virMutexLock(&stream->priv->lock);
if (msg->header.type != VIR_NET_STREAM)
goto cleanup;
if (!virNetServerProgramMatches(stream->prog, msg))
goto cleanup;
if (msg->header.proc != stream->procedure ||
msg->header.serial != stream->serial)
goto cleanup;
VIR_DEBUG("Incoming client=%p, rx=%p, serial=%u, proc=%d, status=%d",
client, stream->rx, msg->header.proc,
msg->header.serial, msg->header.status);
virNetMessageQueuePush(&stream->rx, msg);
daemonStreamUpdateEvents(stream);
ret = 1;
cleanup:
virMutexUnlock(&stream->priv->lock);
return ret;
}
/*
* @conn: a connection object to associate the stream with
* @header: the method call to associate with the stream
*
* Creates a new stream for this conn
*
* Returns a new stream object, or NULL upon OOM
*/
daemonClientStream *
daemonCreateClientStream(virNetServerClientPtr client,
virStreamPtr st,
virNetServerProgramPtr prog,
virNetMessageHeaderPtr header)
{
daemonClientStream *stream;
daemonClientPrivatePtr priv = virNetServerClientGetPrivateData(client);
VIR_DEBUG("client=%p, proc=%d, serial=%u, st=%p",
client, header->proc, header->serial, st);
if (VIR_ALLOC(stream) < 0)
return NULL;
stream->refs = 1;
stream->priv = priv;
stream->prog = virObjectRef(prog);
stream->procedure = header->proc;
stream->serial = header->serial;
stream->filterID = -1;
stream->st = st;
return stream;
}
/*
* @stream: an unused client stream
*
* Frees the memory associated with this inactive client
* stream
*/
int daemonFreeClientStream(virNetServerClientPtr client,
daemonClientStream *stream)
{
virNetMessagePtr msg;
int ret = 0;
if (!stream)
return 0;
stream->refs--;
if (stream->refs)
return 0;
VIR_DEBUG("client=%p, proc=%d, serial=%u",
client, stream->procedure, stream->serial);
virObjectUnref(stream->prog);
msg = stream->rx;
while (msg) {
virNetMessagePtr tmp = msg->next;
if (client) {
/* Send a dummy reply to free up 'msg' & unblock client rx */
virNetMessageClear(msg);
msg->header.type = VIR_NET_REPLY;
if (virNetServerClientSendMessage(client, msg) < 0) {
virNetServerClientImmediateClose(client);
virNetMessageFree(msg);
ret = -1;
}
} else {
virNetMessageFree(msg);
}
msg = tmp;
}
virObjectUnref(stream->st);
VIR_FREE(stream);
return ret;
}
/*
* @client: a locked client to add the stream to
* @stream: a stream to add
*/
int daemonAddClientStream(virNetServerClientPtr client,
daemonClientStream *stream,
bool transmit)
{
VIR_DEBUG("client=%p, proc=%d, serial=%u, st=%p, transmit=%d",
client, stream->procedure, stream->serial, stream->st, transmit);
daemonClientPrivatePtr priv = virNetServerClientGetPrivateData(client);
if (stream->filterID != -1) {
VIR_WARN("Filter already added to client %p", client);
return -1;
}
if (virStreamEventAddCallback(stream->st, 0,
daemonStreamEvent, client,
virObjectFreeCallback) < 0)
return -1;
virObjectRef(client);
if ((stream->filterID = virNetServerClientAddFilter(client,
daemonStreamFilter,
stream)) < 0) {
virStreamEventRemoveCallback(stream->st);
return -1;
}
if (transmit)
stream->tx = true;
virMutexLock(&priv->lock);
stream->next = priv->streams;
priv->streams = stream;
daemonStreamUpdateEvents(stream);
virMutexUnlock(&priv->lock);
return 0;
}
/*
* @client: a locked client object
* @stream: an inactive, closed stream object
*
* Removes a stream from the list of active streams for the client
*
* Returns 0 if the stream was removed, -1 if it doesn't exist
*/
int
daemonRemoveClientStream(virNetServerClientPtr client,
daemonClientStream *stream)
{
VIR_DEBUG("client=%p, proc=%d, serial=%u, st=%p",
client, stream->procedure, stream->serial, stream->st);
daemonClientPrivatePtr priv = virNetServerClientGetPrivateData(client);
daemonClientStream *curr = priv->streams;
daemonClientStream *prev = NULL;
if (stream->filterID != -1) {
virNetServerClientRemoveFilter(client,
stream->filterID);
stream->filterID = -1;
}
if (!stream->closed) {
stream->closed = true;
virStreamEventRemoveCallback(stream->st);
virStreamAbort(stream->st);
}
while (curr) {
if (curr == stream) {
if (prev)
prev->next = curr->next;
else
priv->streams = curr->next;
return daemonFreeClientStream(client, stream);
}
prev = curr;
curr = curr->next;
}
return -1;
}
void
daemonRemoveAllClientStreams(daemonClientStream *stream)
{
daemonClientStream *tmp;
VIR_DEBUG("stream=%p", stream);
while (stream) {
tmp = stream->next;
if (!stream->closed) {
stream->closed = true;
virStreamEventRemoveCallback(stream->st);
virStreamAbort(stream->st);
}
daemonFreeClientStream(NULL, stream);
VIR_DEBUG("next stream=%p", tmp);
stream = tmp;
}
}
/*
* Returns:
* -1 if fatal error occurred
* 0 if message was fully processed
* 1 if message is still being processed
*/
static int
daemonStreamHandleWriteData(virNetServerClientPtr client,
daemonClientStream *stream,
virNetMessagePtr msg)
{
int ret;
VIR_DEBUG("client=%p, stream=%p, proc=%d, serial=%u, len=%zu, offset=%zu",
client, stream, msg->header.proc, msg->header.serial,
msg->bufferLength, msg->bufferOffset);
ret = virStreamSend(stream->st,
msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset);
if (ret > 0) {
msg->bufferOffset += ret;
/* Partial write, so indicate we have more todo later */
if (msg->bufferOffset < msg->bufferLength)
return 1;
} else if (ret == -2) {
/* Blocking, so indicate we have more todo later */
return 1;
} else {
virNetMessageError rerr;
memset(&rerr, 0, sizeof(rerr));
VIR_INFO("Stream send failed");
stream->closed = true;
virStreamEventRemoveCallback(stream->st);
virStreamAbort(stream->st);
return virNetServerProgramSendReplyError(stream->prog,
client,
msg,
&rerr,
&msg->header);
}
return 0;
}
/*
* Process a finish handshake from the client.
*
* Returns a VIR_NET_OK confirmation if successful, or a VIR_NET_ERROR
* if there was a stream error
*
* Returns 0 if successfully sent RPC reply, -1 upon fatal error
*/
static int
daemonStreamHandleFinish(virNetServerClientPtr client,
daemonClientStream *stream,
virNetMessagePtr msg)
{
int ret;
VIR_DEBUG("client=%p, stream=%p, proc=%d, serial=%u",
client, stream, msg->header.proc, msg->header.serial);
stream->closed = true;
virStreamEventRemoveCallback(stream->st);
ret = virStreamFinish(stream->st);
if (ret < 0) {
virNetMessageError rerr;
memset(&rerr, 0, sizeof(rerr));
return virNetServerProgramSendReplyError(stream->prog,
client,
msg,
&rerr,
&msg->header);
} else {
/* Send zero-length confirm */
return virNetServerProgramSendStreamData(stream->prog,
client,
msg,
stream->procedure,
stream->serial,
NULL, 0);
}
}
/*
* Process an abort request from the client.
*
* Returns 0 if successfully aborted, -1 upon error
*/
static int
daemonStreamHandleAbort(virNetServerClientPtr client,
daemonClientStream *stream,
virNetMessagePtr msg)
{
VIR_DEBUG("client=%p, stream=%p, proc=%d, serial=%u",
client, stream, msg->header.proc, msg->header.serial);
int ret;
bool raise_error = false;
stream->closed = true;
virStreamEventRemoveCallback(stream->st);
ret = virStreamAbort(stream->st);
if (msg->header.status == VIR_NET_ERROR) {
VIR_INFO("stream aborted at client request");
raise_error = (ret < 0);
} else {
virReportError(VIR_ERR_RPC,
_("stream aborted with unexpected status %d"),
msg->header.status);
raise_error = true;
}
if (raise_error) {
virNetMessageError rerr;
memset(&rerr, 0, sizeof(rerr));
return virNetServerProgramSendReplyError(remoteProgram,
client,
msg,
&rerr,
&msg->header);
} else {
/* Send zero-length confirm */
return virNetServerProgramSendStreamData(stream->prog,
client,
msg,
stream->procedure,
stream->serial,
NULL, 0);
}
}
/*
* Called when the stream is signalled has being able to accept
* data writes. Will process all pending incoming messages
* until they're all gone, or I/O blocks
*
* Returns 0 on success, or -1 upon fatal error
*/
static int
daemonStreamHandleWrite(virNetServerClientPtr client,
daemonClientStream *stream)
{
VIR_DEBUG("client=%p, stream=%p", client, stream);
while (stream->rx && !stream->closed) {
virNetMessagePtr msg = stream->rx;
int ret;
switch (msg->header.status) {
case VIR_NET_OK:
ret = daemonStreamHandleFinish(client, stream, msg);
break;
case VIR_NET_CONTINUE:
ret = daemonStreamHandleWriteData(client, stream, msg);
break;
case VIR_NET_ERROR:
default:
ret = daemonStreamHandleAbort(client, stream, msg);
break;
}
if (ret > 0)
break; /* still processing data from msg */
virNetMessageQueueServe(&stream->rx);
if (ret < 0) {
virNetMessageFree(msg);
virNetServerClientImmediateClose(client);
return -1;
}
/* 'CONTINUE' messages don't send a reply (unless error
* occurred), so to release the 'msg' object we need to
* send a fake zero-length reply. Nothing actually gets
* onto the wire, but this causes the client to reset
* its active request count / throttling
*/
if (msg->header.status == VIR_NET_CONTINUE) {
virNetMessageClear(msg);
msg->header.type = VIR_NET_REPLY;
if (virNetServerClientSendMessage(client, msg) < 0) {
virNetMessageFree(msg);
virNetServerClientImmediateClose(client);
return -1;
}
}
}
return 0;
}
/*
* Invoked when a stream is signalled as having data
* available to read. This reads up to one message
* worth of data, and then queues that for transmission
* to the client.
*
* Returns 0 if data was queued for TX, or an error RPC
* was sent, or -1 on fatal error, indicating client should
* be killed
*/
static int
daemonStreamHandleRead(virNetServerClientPtr client,
daemonClientStream *stream)
{
virNetMessagePtr msg = NULL;
virNetMessageError rerr;
char *buffer;
size_t bufferLen = VIR_NET_MESSAGE_LEGACY_PAYLOAD_MAX;
int ret = -1;
int rv;
VIR_DEBUG("client=%p, stream=%p tx=%d closed=%d",
client, stream, stream->tx, stream->closed);
/* We might have had an event pending before we shut
* down the stream, so if we're marked as closed,
* then do nothing
*/
if (stream->closed)
return 0;
/* Shouldn't ever be called unless we're marked able to
* transmit, but doesn't hurt to check */
if (!stream->tx)
return 0;
memset(&rerr, 0, sizeof(rerr));
if (VIR_ALLOC_N(buffer, bufferLen) < 0)
return -1;
if (!(msg = virNetMessageNew(false)))
goto cleanup;
rv = virStreamRecv(stream->st, buffer, bufferLen);
if (rv == -2) {
/* Should never get this, since we're only called when we know
* we're readable, but hey things change... */
} else if (rv < 0) {
if (virNetServerProgramSendStreamError(remoteProgram,
client,
msg,
&rerr,
stream->procedure,
stream->serial) < 0)
goto cleanup;
msg = NULL;
} else {
stream->tx = false;
if (rv == 0)
stream->recvEOF = true;
msg->cb = daemonStreamMessageFinished;
msg->opaque = stream;
stream->refs++;
if (virNetServerProgramSendStreamData(remoteProgram,
client,
msg,
stream->procedure,
stream->serial,
buffer, rv) < 0)
goto cleanup;
msg = NULL;
}
ret = 0;
cleanup:
VIR_FREE(buffer);
virNetMessageFree(msg);
return ret;
}
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