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libvirt/tests/qemuxml2argvmock.c
Daniel P. Berrangé 30fb2276d8 qemu: support passing pre-opened UNIX socket listen FD
There is a race condition when spawning QEMU where libvirt has spawned
QEMU but the monitor socket is not yet open. Libvirt has to repeatedly
try to connect() to QEMU's monitor until eventually it succeeds, or
times out. We use kill() to check if QEMU is still alive so we avoid
waiting a long time if QEMU exited, but having a timeout at all is still
unpleasant.

With QEMU 2.12 we can pass in a pre-opened FD for UNIX domain or TCP
sockets. If libvirt has called bind() and listen() on this FD, then we
have a guarantee that libvirt can immediately call connect() and
succeed without any race.

Although we only really care about this for the monitor socket and agent
socket, this patch does FD passing for all UNIX socket based character
devices since there appears to be no downside to it.

We don't do FD passing for TCP sockets, however, because it is only
possible to pass a single FD, while some hostnames may require listening
on multiple FDs to cover IPv4 and IPv6 concurrently.

Reviewed-by: John Ferlan <jferlan@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2018-06-05 17:30:28 +01:00

236 lines
5.4 KiB
C

/*
* Copyright (C) 2014-2016 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: Michal Privoznik <mprivozn@redhat.com>
*/
#include <config.h>
#include "internal.h"
#include "viralloc.h"
#include "vircommand.h"
#include "vircrypto.h"
#include "virmock.h"
#include "virnetdev.h"
#include "virnetdevip.h"
#include "virnetdevtap.h"
#include "virnetdevopenvswitch.h"
#include "virnuma.h"
#include "virrandom.h"
#include "virscsi.h"
#include "virscsivhost.h"
#include "virstring.h"
#include "virtpm.h"
#include "virutil.h"
#include "qemu/qemu_interface.h"
#include "qemu/qemu_command.h"
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
#define VIR_FROM_THIS VIR_FROM_NONE
long virGetSystemPageSize(void)
{
return 4096;
}
time_t time(time_t *t)
{
const time_t ret = 1234567890;
if (t)
*t = ret;
return ret;
}
bool
virNumaIsAvailable(void)
{
return true;
}
int
virNumaGetMaxNode(void)
{
return 7;
}
/* We shouldn't need to mock virNumaNodeIsAvailable() and *definitely* not
* virNumaNodesetIsAvailable(), but it seems to be the only way to get
* mocking to work with Clang on FreeBSD, so keep these duplicates around
* until we figure out a cleaner solution */
bool
virNumaNodeIsAvailable(int node)
{
return node >= 0 && node <= virNumaGetMaxNode();
}
bool
virNumaNodesetIsAvailable(virBitmapPtr nodeset)
{
ssize_t bit = -1;
if (!nodeset)
return true;
while ((bit = virBitmapNextSetBit(nodeset, bit)) >= 0) {
if (virNumaNodeIsAvailable(bit))
continue;
return false;
}
return true;
}
char *
virTPMCreateCancelPath(const char *devpath)
{
char *path;
(void)devpath;
ignore_value(VIR_STRDUP(path, "/sys/class/misc/tpm0/device/cancel"));
return path;
}
/**
* Large values for memory would fail on 32 bit systems, despite having
* variables that support it.
*/
unsigned long long
virMemoryMaxValue(bool capped ATTRIBUTE_UNUSED)
{
return LLONG_MAX;
}
char *
virSCSIDeviceGetSgName(const char *sysfs_prefix ATTRIBUTE_UNUSED,
const char *adapter ATTRIBUTE_UNUSED,
unsigned int bus ATTRIBUTE_UNUSED,
unsigned int target ATTRIBUTE_UNUSED,
unsigned long long unit ATTRIBUTE_UNUSED)
{
char *ret;
ignore_value(VIR_STRDUP(ret, "sg0"));
return ret;
}
int
virSCSIVHostOpenVhostSCSI(int *vhostfd)
{
*vhostfd = STDERR_FILENO + 1;
return 0;
}
int
virNetDevTapCreate(char **ifname,
const char *tunpath ATTRIBUTE_UNUSED,
int *tapfd,
size_t tapfdSize,
unsigned int flags ATTRIBUTE_UNUSED)
{
size_t i;
for (i = 0; i < tapfdSize; i++)
tapfd[i] = STDERR_FILENO + 1 + i;
VIR_FREE(*ifname);
return VIR_STRDUP(*ifname, "vnet0");
}
int
virNetDevSetMAC(const char *ifname ATTRIBUTE_UNUSED,
const virMacAddr *macaddr ATTRIBUTE_UNUSED)
{
return 0;
}
int virNetDevIPAddrAdd(const char *ifname ATTRIBUTE_UNUSED,
virSocketAddr *addr ATTRIBUTE_UNUSED,
virSocketAddr *peer ATTRIBUTE_UNUSED,
unsigned int prefix ATTRIBUTE_UNUSED)
{
return 0;
}
int
virNetDevSetOnline(const char *ifname ATTRIBUTE_UNUSED,
bool online ATTRIBUTE_UNUSED)
{
return 0;
}
int
virNetDevRunEthernetScript(const char *ifname ATTRIBUTE_UNUSED,
const char *script ATTRIBUTE_UNUSED)
{
return 0;
}
void
virCommandPassFD(virCommandPtr cmd ATTRIBUTE_UNUSED,
int fd ATTRIBUTE_UNUSED,
unsigned int flags ATTRIBUTE_UNUSED)
{
/* nada */
}
int
virNetDevOpenvswitchGetVhostuserIfname(const char *path ATTRIBUTE_UNUSED,
char **ifname)
{
return VIR_STRDUP(*ifname, "vhost-user0");
}
int
qemuInterfaceOpenVhostNet(virDomainDefPtr def ATTRIBUTE_UNUSED,
virDomainNetDefPtr net,
int *vhostfd,
size_t *vhostfdSize)
{
size_t i;
if (!(net->model && STREQ(net->model, "virtio"))) {
*vhostfdSize = 0;
return 0;
}
for (i = 0; i < *vhostfdSize; i++)
vhostfd[i] = STDERR_FILENO + 42 + i;
return 0;
}
int
qemuOpenChrChardevUNIXSocket(const virDomainChrSourceDef *dev ATTRIBUTE_UNUSED)
{
/* We need to return an FD number for a UNIX listener socket,
* which will be given to QEMU via a CLI arg. We need a fixed
* number to get stable tests. This is obviously not a real
* FD number, so when virCommand closes the FD in the parent
* it will get EINVAL, but that's (hopefully) not going to
* be a problem....
*/
if (fcntl(1729, F_GETFD) != -1)
abort();
return 1729;
}