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libvirt/daemon/dispatch.c

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/*
* dispatch.h: RPC message dispatching infrastructure
*
* Copyright (C) 2007, 2008, 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: Richard W.M. Jones <rjones@redhat.com>
* Author: Daniel P. Berrange <berrange@redhat.com>
*/
#include <config.h>
#include "dispatch.h"
#include "remote.h"
#include "memory.h"
/* Convert a libvirt virError object into wire format */
static void
remoteDispatchCopyError (remote_error *rerr,
virErrorPtr verr)
{
rerr->code = verr->code;
rerr->domain = verr->domain;
rerr->message = verr->message ? malloc(sizeof(char*)) : NULL;
if (rerr->message) *rerr->message = strdup(verr->message);
rerr->level = verr->level;
rerr->str1 = verr->str1 ? malloc(sizeof(char*)) : NULL;
if (rerr->str1) *rerr->str1 = strdup(verr->str1);
rerr->str2 = verr->str2 ? malloc(sizeof(char*)) : NULL;
if (rerr->str2) *rerr->str2 = strdup(verr->str2);
rerr->str3 = verr->str3 ? malloc(sizeof(char*)) : NULL;
if (rerr->str3) *rerr->str3 = strdup(verr->str3);
rerr->int1 = verr->int1;
rerr->int2 = verr->int2;
}
/* A set of helpers for sending back errors to client
in various ways .... */
static void
remoteDispatchStringError (remote_error *rerr,
int code, const char *msg)
{
virError verr;
memset(&verr, 0, sizeof verr);
/* Construct the dummy libvirt virError. */
verr.code = code;
verr.domain = VIR_FROM_REMOTE;
verr.message = (char *)msg;
verr.level = VIR_ERR_ERROR;
verr.str1 = (char *)msg;
remoteDispatchCopyError(rerr, &verr);
}
void remoteDispatchAuthError (remote_error *rerr)
{
remoteDispatchStringError (rerr, VIR_ERR_AUTH_FAILED, "authentication failed");
}
void remoteDispatchFormatError (remote_error *rerr,
const char *fmt, ...)
{
va_list args;
char msgbuf[1024];
char *msg = msgbuf;
va_start (args, fmt);
vsnprintf (msgbuf, sizeof msgbuf, fmt, args);
va_end (args);
remoteDispatchStringError (rerr, VIR_ERR_RPC, msg);
}
void remoteDispatchGenericError (remote_error *rerr)
{
remoteDispatchStringError(rerr,
VIR_ERR_INTERNAL_ERROR,
"library function returned error but did not set virterror");
}
void remoteDispatchOOMError (remote_error *rerr)
{
remoteDispatchStringError(rerr,
VIR_ERR_NO_MEMORY,
"out of memory");
}
void remoteDispatchConnError (remote_error *rerr,
virConnectPtr conn)
{
virErrorPtr verr;
if (conn)
verr = virConnGetLastError(conn);
else
verr = virGetLastError();
if (verr)
remoteDispatchCopyError(rerr, verr);
else
remoteDispatchGenericError(rerr);
}
static int
remoteSerializeError(struct qemud_client *client,
remote_error *rerr,
int program,
int version,
int procedure,
int type,
int serial)
{
XDR xdr;
unsigned int len;
struct qemud_client_message *msg = NULL;
DEBUG("prog=%d ver=%d proc=%d type=%d serial=%d, msg=%s",
program, version, procedure, type, serial,
rerr->message ? *rerr->message : "(none)");
if (VIR_ALLOC(msg) < 0)
goto fatal_error;
/* Return header. */
msg->hdr.prog = program;
msg->hdr.vers = version;
msg->hdr.proc = procedure;
msg->hdr.type = type;
msg->hdr.serial = serial;
msg->hdr.status = REMOTE_ERROR;
msg->bufferLength = sizeof(msg->buffer);
/* Serialise the return header. */
xdrmem_create (&xdr,
msg->buffer,
msg->bufferLength,
XDR_ENCODE);
len = 0; /* We'll come back and write this later. */
if (!xdr_u_int (&xdr, &len))
goto xdr_error;
if (!xdr_remote_message_header (&xdr, &msg->hdr))
goto xdr_error;
/* Error was not set, so synthesize a generic error message. */
if (rerr->code == 0)
remoteDispatchGenericError(rerr);
if (!xdr_remote_error (&xdr, rerr))
goto xdr_error;
/* Write the length word. */
len = xdr_getpos (&xdr);
if (xdr_setpos (&xdr, 0) == 0)
goto xdr_error;
if (!xdr_u_int (&xdr, &len))
goto xdr_error;
xdr_destroy (&xdr);
msg->bufferLength = len;
msg->bufferOffset = 0;
/* Put reply on end of tx queue to send out */
qemudClientMessageQueuePush(&client->tx, msg);
qemudUpdateClientEvent(client);
xdr_free((xdrproc_t)xdr_remote_error, (char *)rerr);
return 0;
xdr_error:
xdr_destroy(&xdr);
VIR_FREE(msg);
fatal_error:
xdr_free((xdrproc_t)xdr_remote_error, (char *)rerr);
return -1;
}
/*
* @client: the client to send the error to
* @rerr: the error object to send
* @req: the message this error is in reply to
*
* Send an error message to the client
*
* Returns 0 if the error was sent, -1 upon fatal error
*/
int
remoteSerializeReplyError(struct qemud_client *client,
remote_error *rerr,
remote_message_header *req) {
/*
* For data streams, errors are sent back as data streams
* For method calls, errors are sent back as method replies
*/
return remoteSerializeError(client,
rerr,
req->prog,
req->vers,
req->proc,
req->type == REMOTE_STREAM ? REMOTE_STREAM : REMOTE_REPLY,
req->serial);
}
int
remoteSerializeStreamError(struct qemud_client *client,
remote_error *rerr,
int proc,
int serial)
{
return remoteSerializeError(client,
rerr,
REMOTE_PROGRAM,
REMOTE_PROTOCOL_VERSION,
proc,
REMOTE_STREAM,
serial);
}
/*
* @msg: the complete incoming message, whose header to decode
*
* Decodes the header part of the client message, but does not
* validate the decoded fields in the header. It expects
* bufferLength to refer to length of the data packet. Upon
* return bufferOffset will refer to the amount of the packet
* consumed by decoding of the header.
*
* returns 0 if successfully decoded, -1 upon fatal error
*/
int
remoteDecodeClientMessageHeader (struct qemud_client_message *msg)
{
XDR xdr;
int ret = -1;
msg->bufferOffset = REMOTE_MESSAGE_HEADER_XDR_LEN;
/* Parse the header. */
xdrmem_create (&xdr,
msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset,
XDR_DECODE);
if (!xdr_remote_message_header (&xdr, &msg->hdr))
goto cleanup;
msg->bufferOffset += xdr_getpos(&xdr);
ret = 0;
cleanup:
xdr_destroy(&xdr);
return ret;
}
/*
* @msg: the outgoing message, whose header to encode
*
* Encodes the header part of the client message, setting the
* message offset ready to encode the payload. Leaves space
* for the length field later. Upon return bufferLength will
* refer to the total available space for message, while
* bufferOffset will refer to current space used by header
*
* returns 0 if successfully encoded, -1 upon fatal error
*/
int
remoteEncodeClientMessageHeader (struct qemud_client_message *msg)
{
XDR xdr;
int ret = -1;
unsigned int len = 0;
msg->bufferLength = sizeof(msg->buffer);
msg->bufferOffset = 0;
/* Format the header. */
xdrmem_create (&xdr,
msg->buffer,
msg->bufferLength,
XDR_ENCODE);
/* The real value is filled in shortly */
if (!xdr_u_int (&xdr, &len)) {
goto cleanup;
}
if (!xdr_remote_message_header (&xdr, &msg->hdr))
goto cleanup;
len = xdr_getpos(&xdr);
xdr_setpos(&xdr, 0);
/* Fill in current length - may be re-written later
* if a payload is added
*/
if (!xdr_u_int (&xdr, &len)) {
goto cleanup;
}
msg->bufferOffset += len;
ret = 0;
cleanup:
xdr_destroy(&xdr);
return ret;
}
int
remoteDispatchClientCall (struct qemud_server *server,
struct qemud_client *client,
struct qemud_client_message *msg);
/*
* @server: the unlocked server object
* @client: the locked client object
* @msg: the complete incoming message packet, with header already decoded
*
* This function gets called from qemud when it pulls a incoming
* remote protocol messsage off the dispatch queue for processing.
*
* The @msg parameter must have had its header decoded already by
* calling remoteDecodeClientMessageHeader
*
* Returns 0 if the message was dispatched, -1 upon fatal error
*/
int
remoteDispatchClientRequest (struct qemud_server *server,
struct qemud_client *client,
struct qemud_client_message *msg)
{
int ret;
remote_error rerr;
DEBUG("prog=%d ver=%d type=%d satus=%d serial=%d proc=%d",
msg->hdr.prog, msg->hdr.vers, msg->hdr.type,
msg->hdr.status, msg->hdr.serial, msg->hdr.proc);
memset(&rerr, 0, sizeof rerr);
/* Check version, etc. */
if (msg->hdr.prog != REMOTE_PROGRAM) {
remoteDispatchFormatError (&rerr,
_("program mismatch (actual %x, expected %x)"),
msg->hdr.prog, REMOTE_PROGRAM);
goto error;
}
if (msg->hdr.vers != REMOTE_PROTOCOL_VERSION) {
remoteDispatchFormatError (&rerr,
_("version mismatch (actual %x, expected %x)"),
msg->hdr.vers, REMOTE_PROTOCOL_VERSION);
goto error;
}
switch (msg->hdr.type) {
case REMOTE_CALL:
return remoteDispatchClientCall(server, client, msg);
case REMOTE_STREAM:
/* Since stream data is non-acked, async, we may continue to received
* stream packets after we closed down a stream. Just drop & ignore
* these.
*/
VIR_INFO("Ignoring unexpected stream data serial=%d proc=%d status=%d",
msg->hdr.serial, msg->hdr.proc, msg->hdr.status);
qemudClientMessageRelease(client, msg);
break;
default:
remoteDispatchFormatError (&rerr, _("type (%d) != REMOTE_CALL"),
(int) msg->hdr.type);
goto error;
}
return 0;
error:
ret = remoteSerializeReplyError(client, &rerr, &msg->hdr);
if (ret >= 0)
VIR_FREE(msg);
return ret;
}
/*
* @server: the unlocked server object
* @client: the locked client object
* @msg: the complete incoming method call, with header already decoded
*
* This method is used to dispatch an message representing an
* incoming method call from a client. It decodes the payload
* to obtain method call arguments, invokves the method and
* then sends a reply packet with the return values
*
* Returns 0 if the reply was sent, or -1 upon fatal error
*/
int
remoteDispatchClientCall (struct qemud_server *server,
struct qemud_client *client,
struct qemud_client_message *msg)
{
XDR xdr;
remote_error rerr;
dispatch_args args;
dispatch_ret ret;
const dispatch_data *data = NULL;
int rv = -1;
unsigned int len;
virConnectPtr conn = NULL;
memset(&args, 0, sizeof args);
memset(&ret, 0, sizeof ret);
memset(&rerr, 0, sizeof rerr);
if (msg->hdr.status != REMOTE_OK) {
remoteDispatchFormatError (&rerr, _("status (%d) != REMOTE_OK"),
(int) msg->hdr.status);
goto rpc_error;
}
/* If client is marked as needing auth, don't allow any RPC ops,
* except for authentication ones
*/
if (client->auth) {
if (msg->hdr.proc != REMOTE_PROC_AUTH_LIST &&
msg->hdr.proc != REMOTE_PROC_AUTH_SASL_INIT &&
msg->hdr.proc != REMOTE_PROC_AUTH_SASL_START &&
msg->hdr.proc != REMOTE_PROC_AUTH_SASL_STEP &&
msg->hdr.proc != REMOTE_PROC_AUTH_POLKIT
) {
/* Explicitly *NOT* calling remoteDispatchAuthError() because
we want back-compatability with libvirt clients which don't
support the VIR_ERR_AUTH_FAILED error code */
remoteDispatchFormatError (&rerr, "%s", _("authentication required"));
goto rpc_error;
}
}
data = remoteGetDispatchData(msg->hdr.proc);
if (!data) {
remoteDispatchFormatError (&rerr, _("unknown procedure: %d"),
msg->hdr.proc);
goto rpc_error;
}
/* De-serialize payload with args from the wire message */
xdrmem_create (&xdr,
msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset,
XDR_DECODE);
if (!((data->args_filter)(&xdr, &args))) {
xdr_destroy (&xdr);
remoteDispatchFormatError (&rerr, "%s", _("parse args failed"));
goto rpc_error;
}
xdr_destroy (&xdr);
/* Call function. */
conn = client->conn;
virMutexUnlock(&client->lock);
/*
* When the RPC handler is called:
*
* - Server object is unlocked
* - Client object is unlocked
*
* Without locking, it is safe to use:
*
* 'conn', 'rerr', 'args and 'ret'
*/
rv = (data->fn)(server, client, conn, &msg->hdr, &rerr, &args, &ret);
virMutexLock(&server->lock);
virMutexLock(&client->lock);
virMutexUnlock(&server->lock);
xdr_free (data->args_filter, (char*)&args);
if (rv < 0)
goto rpc_error;
/* Return header. We're re-using same message object, so
* only need to tweak type/status fields */
/*msg->hdr.prog = msg->hdr.prog;*/
/*msg->hdr.vers = msg->hdr.vers;*/
/*msg->hdr.proc = msg->hdr.proc;*/
msg->hdr.type = REMOTE_REPLY;
/*msg->hdr.serial = msg->hdr.serial;*/
msg->hdr.status = REMOTE_OK;
if (remoteEncodeClientMessageHeader(msg) < 0) {
xdr_free (data->ret_filter, (char*)&ret);
goto fatal_error;
}
/* Now for the payload */
xdrmem_create (&xdr,
msg->buffer,
msg->bufferLength,
XDR_ENCODE);
if (xdr_setpos(&xdr, msg->bufferOffset) == 0)
goto xdr_error;
/* If OK, serialise return structure, if error serialise error. */
/* Serialise reply data */
if (!((data->ret_filter) (&xdr, &ret)))
goto xdr_error;
/* Update the length word. */
msg->bufferOffset += xdr_getpos (&xdr);
len = msg->bufferOffset;
if (xdr_setpos (&xdr, 0) == 0)
goto xdr_error;
if (!xdr_u_int (&xdr, &len))
goto xdr_error;
xdr_destroy (&xdr);
xdr_free (data->ret_filter, (char*)&ret);
/* Reset ready for I/O */
msg->bufferLength = len;
msg->bufferOffset = 0;
/* Put reply on end of tx queue to send out */
qemudClientMessageQueuePush(&client->tx, msg);
qemudUpdateClientEvent(client);
return 0;
rpc_error:
/* Semi-bad stuff happened, we can still try to send back
* an RPC error message to client */
rv = remoteSerializeReplyError(client, &rerr, &msg->hdr);
if (rv >= 0)
VIR_FREE(msg);
return rv;
xdr_error:
/* Seriously bad stuff happened, so we'll kill off this client
and not send back any RPC error */
xdr_free (data->ret_filter, (char*)&ret);
xdr_destroy (&xdr);
fatal_error:
return -1;
}
int
remoteSendStreamData(struct qemud_client *client,
struct qemud_client_stream *stream,
const char *data,
unsigned int len)
{
struct qemud_client_message *msg;
XDR xdr;
DEBUG("client=%p stream=%p data=%p len=%d", client, stream, data, len);
if (VIR_ALLOC(msg) < 0) {
return -1;
}
/* Return header. We're re-using same message object, so
* only need to tweak type/status fields */
msg->hdr.prog = REMOTE_PROGRAM;
msg->hdr.vers = REMOTE_PROTOCOL_VERSION;
msg->hdr.proc = stream->procedure;
msg->hdr.type = REMOTE_STREAM;
msg->hdr.serial = stream->serial;
/*
* NB
* data != NULL + len > 0 => REMOTE_CONTINUE (Sending back data)
* data != NULL + len == 0 => REMOTE_CONTINUE (Sending read EOF)
* data == NULL => REMOTE_OK (Sending finish handshake confirmation)
*/
msg->hdr.status = data ? REMOTE_CONTINUE : REMOTE_OK;
if (remoteEncodeClientMessageHeader(msg) < 0)
goto fatal_error;
if (data && len) {
if ((msg->bufferLength - msg->bufferOffset) < len)
goto fatal_error;
/* Now for the payload */
xdrmem_create (&xdr,
msg->buffer,
msg->bufferLength,
XDR_ENCODE);
/* Skip over existing header already written */
if (xdr_setpos(&xdr, msg->bufferOffset) == 0)
goto xdr_error;
memcpy(msg->buffer + msg->bufferOffset, data, len);
msg->bufferOffset += len;
/* Update the length word. */
len = msg->bufferOffset;
if (xdr_setpos (&xdr, 0) == 0)
goto xdr_error;
if (!xdr_u_int (&xdr, &len))
goto xdr_error;
xdr_destroy (&xdr);
DEBUG("Total %d", msg->bufferOffset);
}
if (data)
msg->streamTX = 1;
/* Reset ready for I/O */
msg->bufferLength = msg->bufferOffset;
msg->bufferOffset = 0;
/* Put reply on end of tx queue to send out */
qemudClientMessageQueuePush(&client->tx, msg);
qemudUpdateClientEvent(client);
return 0;
xdr_error:
xdr_destroy (&xdr);
fatal_error:
VIR_FREE(msg);
return -1;
}
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