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libvirt/daemon/stream.c

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/*
* stream.c: APIs for managing client streams
*
* Copyright (C) 2009 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>
*/
#include <config.h>
#include "stream.h"
#include "memory.h"
#include "dispatch.h"
#include "logging.h"
static int
remoteStreamHandleWrite(struct qemud_client *client,
struct qemud_client_stream *stream);
static int
remoteStreamHandleRead(struct qemud_client *client,
struct qemud_client_stream *stream);
static int
remoteStreamHandleFinish(struct qemud_client *client,
struct qemud_client_stream *stream,
struct qemud_client_message *msg);
static int
remoteStreamHandleAbort(struct qemud_client *client,
struct qemud_client_stream *stream,
struct qemud_client_message *msg);
static void
remoteStreamUpdateEvents(struct qemud_client_stream *stream)
{
int newEvents = 0;
if (stream->rx)
newEvents |= VIR_STREAM_EVENT_WRITABLE;
if (stream->tx && !stream->recvEOF)
newEvents |= VIR_STREAM_EVENT_READABLE;
virStreamEventUpdateCallback(stream->st, newEvents);
}
/*
* Callback that gets invoked when a stream becomes writable/readable
*/
static void
remoteStreamEvent(virStreamPtr st, int events, void *opaque)
{
struct qemud_client *client = opaque;
struct qemud_client_stream *stream;
/* XXX sub-optimal - we really should be taking the server lock
* first, but we have no handle to the server object
* We're lucky to get away with it for now, due to this callback
* executing in the main thread, but this should really be fixed
*/
virMutexLock(&client->lock);
stream = remoteFindClientStream(client, st);
if (!stream) {
VIR_WARN("event for client=%p stream st=%p, but missing stream state", client, st);
virStreamEventRemoveCallback(st);
goto cleanup;
}
DEBUG("st=%p events=%d", st, events);
if (events & VIR_STREAM_EVENT_WRITABLE) {
if (remoteStreamHandleWrite(client, stream) < 0) {
remoteRemoveClientStream(client, stream);
qemudDispatchClientFailure(client);
goto cleanup;
}
}
if (!stream->recvEOF &&
(events & (VIR_STREAM_EVENT_READABLE | VIR_STREAM_EVENT_HANGUP))) {
events = events & ~(VIR_STREAM_EVENT_READABLE | VIR_STREAM_EVENT_HANGUP);
if (remoteStreamHandleRead(client, stream) < 0) {
remoteRemoveClientStream(client, stream);
qemudDispatchClientFailure(client);
goto cleanup;
}
}
if (!stream->closed &&
(events & (VIR_STREAM_EVENT_ERROR | VIR_STREAM_EVENT_HANGUP))) {
int ret;
remote_error rerr;
memset(&rerr, 0, sizeof rerr);
stream->closed = 1;
virStreamAbort(stream->st);
if (events & VIR_STREAM_EVENT_HANGUP)
remoteDispatchFormatError(&rerr, "%s", _("stream had unexpected termination"));
else
remoteDispatchFormatError(&rerr, "%s", _("stream had I/O failure"));
ret = remoteSerializeStreamError(client, &rerr, stream->procedure, stream->serial);
remoteRemoveClientStream(client, stream);
if (ret < 0)
qemudDispatchClientFailure(client);
goto cleanup;
}
if (stream->closed) {
remoteRemoveClientStream(client, stream);
} else {
remoteStreamUpdateEvents(stream);
}
cleanup:
virMutexUnlock(&client->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
remoteStreamFilter(struct qemud_client *client,
struct qemud_client_message *msg, void *opaque)
{
struct qemud_client_stream *stream = opaque;
if (msg->hdr.serial == stream->serial &&
msg->hdr.proc == stream->procedure &&
msg->hdr.type == REMOTE_STREAM) {
DEBUG("Incoming rx=%p serial=%d proc=%d status=%d",
stream->rx, msg->hdr.proc, msg->hdr.serial, msg->hdr.status);
/* If there are queued packets, we need to queue all further
* messages, since they must be processed strictly in order.
* If there are no queued packets, then OK/ERROR messages
* should be processed immediately. Data packets are still
* queued to only be processed when the stream is marked as
* writable.
*/
if (stream->rx) {
qemudClientMessageQueuePush(&stream->rx, msg);
remoteStreamUpdateEvents(stream);
} else {
int ret = 0;
switch (msg->hdr.status) {
case REMOTE_OK:
ret = remoteStreamHandleFinish(client, stream, msg);
if (ret == 0)
qemudClientMessageRelease(client, msg);
break;
case REMOTE_CONTINUE:
qemudClientMessageQueuePush(&stream->rx, msg);
remoteStreamUpdateEvents(stream);
break;
case REMOTE_ERROR:
default:
ret = remoteStreamHandleAbort(client, stream, msg);
if (ret == 0)
qemudClientMessageRelease(client, msg);
break;
}
if (ret < 0)
return -1;
}
return 1;
}
return 0;
}
/*
* @conn: a connection object to associate the stream with
* @hdr: the method call to associate with the stram
*
* Creates a new stream for this conn
*
* Returns a new stream object, or NULL upon OOM
*/
struct qemud_client_stream *
remoteCreateClientStream(virConnectPtr conn,
remote_message_header *hdr)
{
struct qemud_client_stream *stream;
DEBUG("proc=%d serial=%d", hdr->proc, hdr->serial);
if (VIR_ALLOC(stream) < 0)
return NULL;
stream->procedure = hdr->proc;
stream->serial = hdr->serial;
stream->st = virStreamNew(conn, VIR_STREAM_NONBLOCK);
if (!stream->st) {
VIR_FREE(stream);
return NULL;
}
stream->filter.query = remoteStreamFilter;
stream->filter.opaque = stream;
return stream;
}
/*
* @stream: an unused client stream
*
* Frees the memory associated with this inactive client
* stream
*/
void remoteFreeClientStream(struct qemud_client *client,
struct qemud_client_stream *stream)
{
struct qemud_client_message *msg;
if (!stream)
return;
DEBUG("proc=%d serial=%d", stream->procedure, stream->serial);
msg = stream->rx;
while (msg) {
struct qemud_client_message *tmp = msg->next;
qemudClientMessageRelease(client, msg);
msg = tmp;
}
virStreamFree(stream->st);
VIR_FREE(stream);
}
/*
* @client: a locked client to add the stream to
* @stream: a stream to add
*/
int remoteAddClientStream(struct qemud_client *client,
struct qemud_client_stream *stream,
int transmit)
{
struct qemud_client_stream *tmp = client->streams;
DEBUG("client=%p proc=%d serial=%d", client, stream->procedure, stream->serial);
if (virStreamEventAddCallback(stream->st, 0,
remoteStreamEvent, client, NULL) < 0)
return -1;
if (tmp) {
while (tmp->next)
tmp = tmp->next;
tmp->next = stream;
} else {
client->streams = stream;
}
stream->filter.next = client->filters;
client->filters = &stream->filter;
if (transmit)
stream->tx = 1;
remoteStreamUpdateEvents(stream);
return 0;
}
/*
* @client: a locked client object
* @procedure: procedure associated with the stream
* @serial: serial number associated with the stream
*
* Finds a existing active stream
*
* Returns a stream object matching the procedure+serial number, or NULL
*/
struct qemud_client_stream *
remoteFindClientStream(struct qemud_client *client,
virStreamPtr st)
{
struct qemud_client_stream *stream = client->streams;
while (stream) {
if (stream->st == st)
return stream;
stream = stream->next;
}
return NULL;
}
/*
* @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 removd, -1 if it doesn't exist
*/
int
remoteRemoveClientStream(struct qemud_client *client,
struct qemud_client_stream *stream)
{
DEBUG("client=%p proc=%d serial=%d", client, stream->procedure, stream->serial);
struct qemud_client_stream *curr = client->streams;
struct qemud_client_stream *prev = NULL;
struct qemud_client_filter *filter = NULL;
if (client->filters == &stream->filter) {
client->filters = client->filters->next;
} else {
filter = client->filters;
while (filter) {
if (filter->next == &stream->filter) {
filter->next = filter->next->next;
break;
}
}
}
if (!stream->closed)
virStreamAbort(stream->st);
while (curr) {
if (curr == stream) {
if (prev)
prev->next = curr->next;
else
client->streams = curr->next;
remoteFreeClientStream(client, stream);
return 0;
}
prev = curr;
curr = curr->next;
}
return -1;
}
/*
* Returns:
* -1 if fatal error occurred
* 0 if message was fully processed
* 1 if message is still being processed
*/
static int
remoteStreamHandleWriteData(struct qemud_client *client,
struct qemud_client_stream *stream,
struct qemud_client_message *msg)
{
remote_error rerr;
int ret;
DEBUG("stream=%p proc=%d serial=%d len=%d offset=%d",
stream, msg->hdr.proc, msg->hdr.serial, msg->bufferLength, msg->bufferOffset);
memset(&rerr, 0, sizeof rerr);
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 {
VIR_INFO0("Stream send failed");
stream->closed = 1;
remoteDispatchConnError(&rerr, client->conn);
return remoteSerializeReplyError(client, &rerr, &msg->hdr);
}
return 0;
}
/*
* Process an finish handshake from the client.
*
* Returns a REMOTE_OK confirmation if successful, or a REMOTE_ERROR
* if there was a stream error
*
* Returns 0 if successfully sent RPC reply, -1 upon fatal error
*/
static int
remoteStreamHandleFinish(struct qemud_client *client,
struct qemud_client_stream *stream,
struct qemud_client_message *msg)
{
remote_error rerr;
int ret;
DEBUG("stream=%p proc=%d serial=%d",
stream, msg->hdr.proc, msg->hdr.serial);
memset(&rerr, 0, sizeof rerr);
stream->closed = 1;
ret = virStreamFinish(stream->st);
if (ret < 0) {
remoteDispatchConnError(&rerr, client->conn);
return remoteSerializeReplyError(client, &rerr, &msg->hdr);
} else {
/* Send zero-length confirm */
if (remoteSendStreamData(client, stream, NULL, 0) < 0)
return -1;
}
return 0;
}
/*
* Process an abort request from the client.
*
* Returns 0 if successfully aborted, -1 upon error
*/
static int
remoteStreamHandleAbort(struct qemud_client *client,
struct qemud_client_stream *stream,
struct qemud_client_message *msg)
{
remote_error rerr;
DEBUG("stream=%p proc=%d serial=%d",
stream, msg->hdr.proc, msg->hdr.serial);
memset(&rerr, 0, sizeof rerr);
stream->closed = 1;
virStreamAbort(stream->st);
if (msg->hdr.status == REMOTE_ERROR)
remoteDispatchFormatError(&rerr, "%s", _("stream aborted at client request"));
else {
VIR_WARN("unexpected stream status %d", msg->hdr.status);
remoteDispatchFormatError(&rerr, _("stream aborted with unexpected status %d"),
msg->hdr.status);
}
return remoteSerializeReplyError(client, &rerr, &msg->hdr);
}
/*
* 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
remoteStreamHandleWrite(struct qemud_client *client,
struct qemud_client_stream *stream)
{
struct qemud_client_message *msg, *tmp;
DEBUG("stream=%p", stream);
msg = stream->rx;
while (msg && !stream->closed) {
int ret;
switch (msg->hdr.status) {
case REMOTE_OK:
ret = remoteStreamHandleFinish(client, stream, msg);
break;
case REMOTE_CONTINUE:
ret = remoteStreamHandleWriteData(client, stream, msg);
break;
case REMOTE_ERROR:
default:
ret = remoteStreamHandleAbort(client, stream, msg);
break;
}
if (ret == 0)
qemudClientMessageQueueServe(&stream->rx);
else if (ret < 0)
return -1;
else
break; /* still processing data */
tmp = msg->next;
qemudClientMessageRelease(client, msg);
msg = tmp;
}
return 0;
}
/*
* Invoked when a stream is signalled as having data
* available to read. This reads upto one message
* worth of data, and then queues that for transmission
* to the client.
*
* Returns 0 if data was queued for TX, or a error RPC
* was sent, or -1 on fatal error, indicating client should
* be killed
*/
static int
remoteStreamHandleRead(struct qemud_client *client,
struct qemud_client_stream *stream)
{
char *buffer;
size_t bufferLen = REMOTE_MESSAGE_PAYLOAD_MAX;
int ret;
DEBUG("stream=%p", stream);
/* Shouldn't ever be called unless we're marked able to
* transmit, but doesn't hurt to check */
if (!stream->tx)
return 0;
if (VIR_ALLOC_N(buffer, bufferLen) < 0)
return -1;
ret = virStreamRecv(stream->st, buffer, bufferLen);
if (ret == -2) {
/* Should never get this, since we're only called when we know
* we're readable, but hey things change... */
ret = 0;
} else if (ret < 0) {
remote_error rerr;
memset(&rerr, 0, sizeof rerr);
remoteDispatchConnError(&rerr, NULL);
ret = remoteSerializeStreamError(client, &rerr, stream->procedure, stream->serial);
} else {
stream->tx = 0;
if (ret == 0)
stream->recvEOF = 1;
ret = remoteSendStreamData(client, stream, buffer, ret);
}
VIR_FREE(buffer);
return ret;
}
/*
* 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
*/
void
remoteStreamMessageFinished(struct qemud_client *client,
struct qemud_client_message *msg)
{
struct qemud_client_stream *stream = client->streams;
while (stream) {
if (msg->hdr.proc == stream->procedure &&
msg->hdr.serial == stream->serial)
break;
stream = stream->next;
}
DEBUG("Message client=%p stream=%p proc=%d serial=%d", client, stream, msg->hdr.proc, msg->hdr.serial);
if (stream) {
stream->tx = 1;
remoteStreamUpdateEvents(stream);
}
}
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