libvirt/src/rpc/virnetmessage.c

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/*
* virnetmessage.c: basic RPC message encoding/decoding
*
* Copyright (C) 2010-2012 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/>.
*/
#include <config.h>
#include <stdlib.h>
#include <unistd.h>
#include "virnetmessage.h"
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#include "viralloc.h"
#include "virerror.h"
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#include "virlog.h"
#include "virfile.h"
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#include "virutil.h"
#include "virstring.h"
#define VIR_FROM_THIS VIR_FROM_RPC
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virNetMessagePtr virNetMessageNew(bool tracked)
{
virNetMessagePtr msg;
if (VIR_ALLOC(msg) < 0)
return NULL;
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msg->tracked = tracked;
VIR_DEBUG("msg=%p tracked=%d", msg, tracked);
return msg;
}
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void virNetMessageClear(virNetMessagePtr msg)
{
bool tracked = msg->tracked;
size_t i;
VIR_DEBUG("msg=%p nfds=%zu", msg, msg->nfds);
for (i = 0; i < msg->nfds; i++)
VIR_FORCE_CLOSE(msg->fds[i]);
VIR_FREE(msg->fds);
VIR_FREE(msg->buffer);
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memset(msg, 0, sizeof(*msg));
msg->tracked = tracked;
}
void virNetMessageFree(virNetMessagePtr msg)
{
size_t i;
if (!msg)
return;
VIR_DEBUG("msg=%p nfds=%zu cb=%p", msg, msg->nfds, msg->cb);
if (msg->cb)
msg->cb(msg, msg->opaque);
for (i = 0; i < msg->nfds; i++)
VIR_FORCE_CLOSE(msg->fds[i]);
VIR_FREE(msg->buffer);
VIR_FREE(msg->fds);
VIR_FREE(msg);
}
void virNetMessageQueuePush(virNetMessagePtr *queue, virNetMessagePtr msg)
{
virNetMessagePtr tmp = *queue;
if (tmp) {
while (tmp->next)
tmp = tmp->next;
tmp->next = msg;
} else {
*queue = msg;
}
}
virNetMessagePtr virNetMessageQueueServe(virNetMessagePtr *queue)
{
virNetMessagePtr tmp = *queue;
if (tmp) {
*queue = tmp->next;
tmp->next = NULL;
}
return tmp;
}
int virNetMessageDecodeLength(virNetMessagePtr msg)
{
XDR xdr;
unsigned int len;
int ret = -1;
xdrmem_create(&xdr, msg->buffer,
msg->bufferLength, XDR_DECODE);
if (!xdr_u_int(&xdr, &len)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to decode message length"));
goto cleanup;
}
msg->bufferOffset = xdr_getpos(&xdr);
if (len < VIR_NET_MESSAGE_LEN_MAX) {
virReportError(VIR_ERR_RPC,
_("packet %d bytes received from server too small, want %d"),
len, VIR_NET_MESSAGE_LEN_MAX);
goto cleanup;
}
/* Length includes length word - adjust to real length to read. */
len -= VIR_NET_MESSAGE_LEN_MAX;
if (len > VIR_NET_MESSAGE_MAX) {
virReportError(VIR_ERR_RPC,
_("packet %d bytes received from server too large, want %d"),
len, VIR_NET_MESSAGE_MAX);
goto cleanup;
}
/* Extend our declared buffer length and carry
on reading the header + payload */
msg->bufferLength += len;
if (VIR_REALLOC_N(msg->buffer, msg->bufferLength) < 0)
goto cleanup;
VIR_DEBUG("Got length, now need %zu total (%u more)",
msg->bufferLength, len);
ret = 0;
cleanup:
xdr_destroy(&xdr);
return ret;
}
/*
* @msg: the complete incoming message, whose header to decode
*
* Decodes the header part of the 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 virNetMessageDecodeHeader(virNetMessagePtr msg)
{
XDR xdr;
int ret = -1;
if (msg->bufferLength < VIR_NET_MESSAGE_LEN_MAX) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Unable to decode header until len is received"));
return -1;
}
msg->bufferOffset = VIR_NET_MESSAGE_LEN_MAX;
/* Parse the header. */
xdrmem_create(&xdr,
msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset,
XDR_DECODE);
if (!xdr_virNetMessageHeader(&xdr, &msg->header)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to decode message header"));
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 length word and header of the 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 virNetMessageEncodeHeader(virNetMessagePtr msg)
{
XDR xdr;
int ret = -1;
unsigned int len = 0;
msg->bufferLength = VIR_NET_MESSAGE_INITIAL + VIR_NET_MESSAGE_LEN_MAX;
if (VIR_REALLOC_N(msg->buffer, msg->bufferLength) < 0)
return ret;
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)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode message length"));
goto cleanup;
}
if (!xdr_virNetMessageHeader(&xdr, &msg->header)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode message header"));
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)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to re-encode message length"));
goto cleanup;
}
msg->bufferOffset += len;
ret = 0;
cleanup:
xdr_destroy(&xdr);
return ret;
}
int virNetMessageEncodeNumFDs(virNetMessagePtr msg)
{
XDR xdr;
unsigned int numFDs = msg->nfds;
int ret = -1;
xdrmem_create(&xdr, msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset, XDR_ENCODE);
if (numFDs > VIR_NET_MESSAGE_NUM_FDS_MAX) {
virReportError(VIR_ERR_RPC,
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_("Too many FDs to send %d, expected %d maximum"),
numFDs, VIR_NET_MESSAGE_NUM_FDS_MAX);
goto cleanup;
}
if (!xdr_u_int(&xdr, &numFDs)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode number of FDs"));
goto cleanup;
}
msg->bufferOffset += xdr_getpos(&xdr);
VIR_DEBUG("Send %zu FDs to peer", msg->nfds);
ret = 0;
cleanup:
xdr_destroy(&xdr);
return ret;
}
int virNetMessageDecodeNumFDs(virNetMessagePtr msg)
{
XDR xdr;
unsigned int numFDs;
int ret = -1;
size_t i;
xdrmem_create(&xdr, msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset, XDR_DECODE);
if (!xdr_u_int(&xdr, &numFDs)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to decode number of FDs"));
goto cleanup;
}
msg->bufferOffset += xdr_getpos(&xdr);
if (numFDs > VIR_NET_MESSAGE_NUM_FDS_MAX) {
virReportError(VIR_ERR_RPC,
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_("Received too many FDs %d, expected %d maximum"),
numFDs, VIR_NET_MESSAGE_NUM_FDS_MAX);
goto cleanup;
}
msg->nfds = numFDs;
if (VIR_ALLOC_N(msg->fds, msg->nfds) < 0)
goto cleanup;
for (i = 0; i < msg->nfds; i++)
msg->fds[i] = -1;
VIR_DEBUG("Got %zu FDs from peer", msg->nfds);
ret = 0;
cleanup:
xdr_destroy(&xdr);
return ret;
}
int virNetMessageEncodePayload(virNetMessagePtr msg,
xdrproc_t filter,
void *data)
{
XDR xdr;
unsigned int msglen;
/* Serialise payload of the message. This assumes that
* virNetMessageEncodeHeader has already been run, so
* just appends to that data */
xdrmem_create(&xdr, msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset, XDR_ENCODE);
/* Try to encode the payload. If the buffer is too small increase it. */
while (!(*filter)(&xdr, data, 0)) {
unsigned int newlen = (msg->bufferLength - VIR_NET_MESSAGE_LEN_MAX) * 4;
if (newlen > VIR_NET_MESSAGE_MAX) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode message payload"));
goto error;
}
xdr_destroy(&xdr);
msg->bufferLength = newlen + VIR_NET_MESSAGE_LEN_MAX;
if (VIR_REALLOC_N(msg->buffer, msg->bufferLength) < 0)
goto error;
xdrmem_create(&xdr, msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset, XDR_ENCODE);
VIR_DEBUG("Increased message buffer length = %zu", msg->bufferLength);
}
/* Get the length stored in buffer. */
msg->bufferOffset += xdr_getpos(&xdr);
xdr_destroy(&xdr);
/* Re-encode the length word. */
VIR_DEBUG("Encode length as %zu", msg->bufferOffset);
xdrmem_create(&xdr, msg->buffer, VIR_NET_MESSAGE_HEADER_XDR_LEN, XDR_ENCODE);
msglen = msg->bufferOffset;
if (!xdr_u_int(&xdr, &msglen)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode message length"));
goto error;
}
xdr_destroy(&xdr);
msg->bufferLength = msg->bufferOffset;
msg->bufferOffset = 0;
return 0;
error:
xdr_destroy(&xdr);
return -1;
}
int virNetMessageDecodePayload(virNetMessagePtr msg,
xdrproc_t filter,
void *data)
{
XDR xdr;
/* Deserialise payload of the message. This assumes that
* virNetMessageDecodeHeader has already been run, so
* just start from after that data */
xdrmem_create(&xdr, msg->buffer + msg->bufferOffset,
msg->bufferLength - msg->bufferOffset, XDR_DECODE);
if (!(*filter)(&xdr, data, 0)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to decode message payload"));
goto error;
}
/* Get the length stored in buffer. */
msg->bufferLength += xdr_getpos(&xdr);
xdr_destroy(&xdr);
return 0;
error:
xdr_destroy(&xdr);
return -1;
}
int virNetMessageEncodePayloadRaw(virNetMessagePtr msg,
const char *data,
size_t len)
{
XDR xdr;
unsigned int msglen;
/* If the message buffer is too small for the payload increase it accordingly. */
if ((msg->bufferLength - msg->bufferOffset) < len) {
if ((msg->bufferOffset + len) >
(VIR_NET_MESSAGE_MAX + VIR_NET_MESSAGE_LEN_MAX)) {
virReportError(VIR_ERR_RPC,
_("Stream data too long to send "
"(%zu bytes needed, %zu bytes available)"),
len,
VIR_NET_MESSAGE_MAX +
VIR_NET_MESSAGE_LEN_MAX -
msg->bufferOffset);
return -1;
}
msg->bufferLength = msg->bufferOffset + len;
if (VIR_REALLOC_N(msg->buffer, msg->bufferLength) < 0)
return -1;
VIR_DEBUG("Increased message buffer length = %zu", msg->bufferLength);
}
memcpy(msg->buffer + msg->bufferOffset, data, len);
msg->bufferOffset += len;
/* Re-encode the length word. */
VIR_DEBUG("Encode length as %zu", msg->bufferOffset);
xdrmem_create(&xdr, msg->buffer, VIR_NET_MESSAGE_HEADER_XDR_LEN, XDR_ENCODE);
msglen = msg->bufferOffset;
if (!xdr_u_int(&xdr, &msglen)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode message length"));
goto error;
}
xdr_destroy(&xdr);
msg->bufferLength = msg->bufferOffset;
msg->bufferOffset = 0;
return 0;
error:
xdr_destroy(&xdr);
return -1;
}
int virNetMessageEncodePayloadEmpty(virNetMessagePtr msg)
{
XDR xdr;
unsigned int msglen;
/* Re-encode the length word. */
VIR_DEBUG("Encode length as %zu", msg->bufferOffset);
xdrmem_create(&xdr, msg->buffer, VIR_NET_MESSAGE_HEADER_XDR_LEN, XDR_ENCODE);
msglen = msg->bufferOffset;
if (!xdr_u_int(&xdr, &msglen)) {
virReportError(VIR_ERR_RPC, "%s", _("Unable to encode message length"));
goto error;
}
xdr_destroy(&xdr);
msg->bufferLength = msg->bufferOffset;
msg->bufferOffset = 0;
return 0;
error:
xdr_destroy(&xdr);
return -1;
}
void virNetMessageSaveError(virNetMessageErrorPtr rerr)
{
/* This func may be called several times & the first
* error is the one we want because we don't want
* cleanup code overwriting the first one.
*/
if (rerr->code != VIR_ERR_OK)
return;
memset(rerr, 0, sizeof(*rerr));
virErrorPtr verr = virGetLastError();
if (verr) {
rerr->code = verr->code;
rerr->domain = verr->domain;
if (verr->message && VIR_ALLOC(rerr->message) == 0 &&
VIR_STRDUP_QUIET(*rerr->message, verr->message) < 0)
VIR_FREE(rerr->message);
rerr->level = verr->level;
if (verr->str1 && VIR_ALLOC(rerr->str1) == 0 &&
VIR_STRDUP_QUIET(*rerr->str1, verr->str1) < 0)
VIR_FREE(rerr->str1);
if (verr->str2 && VIR_ALLOC(rerr->str2) == 0 &&
VIR_STRDUP_QUIET(*rerr->str2, verr->str2) < 0)
VIR_FREE(rerr->str2);
if (verr->str3 && VIR_ALLOC(rerr->str3) == 0 &&
VIR_STRDUP_QUIET(*rerr->str3, verr->str3) < 0)
VIR_FREE(rerr->str3);
rerr->int1 = verr->int1;
rerr->int2 = verr->int2;
} else {
rerr->code = VIR_ERR_INTERNAL_ERROR;
rerr->domain = VIR_FROM_RPC;
if (VIR_ALLOC_QUIET(rerr->message) == 0 &&
VIR_STRDUP_QUIET(*rerr->message,
_("Library function returned error but did not set virError")) < 0)
VIR_FREE(rerr->message);
rerr->level = VIR_ERR_ERROR;
}
}
int virNetMessageDupFD(virNetMessagePtr msg,
size_t slot)
{
int fd;
if (slot >= msg->nfds) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("No FD available at slot %zu"), slot);
return -1;
}
if ((fd = dup(msg->fds[slot])) < 0) {
virReportSystemError(errno,
_("Unable to duplicate FD %d"),
msg->fds[slot]);
return -1;
}
if (virSetInherit(fd, false) < 0) {
VIR_FORCE_CLOSE(fd);
virReportSystemError(errno,
_("Cannot set close-on-exec %d"),
fd);
return -1;
}
return fd;
}