libvirt/src/qemu/qemu_slirp.c

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/*
* qemu_slirp.c: QEMU Slirp support
*
* 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 "qemu_dbus.h"
#include "qemu_extdevice.h"
#include "qemu_security.h"
#include "qemu_slirp.h"
#include "viralloc.h"
#include "virenum.h"
#include "virerror.h"
#include "virjson.h"
#include "virlog.h"
#include "virpidfile.h"
#include "virstring.h"
#include "virtime.h"
#define VIR_FROM_THIS VIR_FROM_NONE
VIR_LOG_INIT("qemu.slirp");
VIR_ENUM_IMPL(qemuSlirpFeature,
QEMU_SLIRP_FEATURE_LAST,
"",
"ipv4",
"ipv6",
"tftp",
"dbus-address",
"dbus-p2p",
"migrate",
"restrict",
"exit-with-parent",
);
void
qemuSlirpFree(qemuSlirpPtr slirp)
{
if (!slirp)
return;
VIR_FORCE_CLOSE(slirp->fd[0]);
VIR_FORCE_CLOSE(slirp->fd[1]);
virBitmapFree(slirp->features);
VIR_FREE(slirp);
}
void
qemuSlirpSetFeature(qemuSlirpPtr slirp,
qemuSlirpFeature feature)
{
ignore_value(virBitmapSetBit(slirp->features, feature));
}
bool
qemuSlirpHasFeature(const qemuSlirp *slirp,
qemuSlirpFeature feature)
{
return virBitmapIsBitSet(slirp->features, feature);
}
qemuSlirpPtr
qemuSlirpNew(void)
{
g_autoptr(qemuSlirp) slirp = g_new0(qemuSlirp, 1);
slirp->features = virBitmapNew(QEMU_SLIRP_FEATURE_LAST);
slirp->pid = (pid_t)-1;
slirp->fd[0] = slirp->fd[1] = -1;
return g_steal_pointer(&slirp);
}
qemuSlirpPtr
qemuSlirpNewForHelper(const char *helper)
{
g_autoptr(qemuSlirp) slirp = NULL;
g_autoptr(virCommand) cmd = NULL;
g_autofree char *output = NULL;
g_autoptr(virJSONValue) doc = NULL;
virJSONValuePtr featuresJSON;
size_t i, nfeatures;
slirp = qemuSlirpNew();
if (!slirp) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Failed to allocate slirp for '%s'"), helper);
return NULL;
}
cmd = virCommandNewArgList(helper, "--print-capabilities", NULL);
virCommandSetOutputBuffer(cmd, &output);
if (virCommandRun(cmd, NULL) < 0)
return NULL;
if (!(doc = virJSONValueFromString(output)) ||
!(featuresJSON = virJSONValueObjectGetArray(doc, "features"))) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("unable to parse json capabilities '%s'"),
helper);
return NULL;
}
nfeatures = virJSONValueArraySize(featuresJSON);
for (i = 0; i < nfeatures; i++) {
virJSONValuePtr item = virJSONValueArrayGet(featuresJSON, i);
const char *tmpStr = virJSONValueGetString(item);
int tmp;
if ((tmp = qemuSlirpFeatureTypeFromString(tmpStr)) <= 0) {
VIR_WARN("unknown slirp feature %s", tmpStr);
continue;
}
qemuSlirpSetFeature(slirp, tmp);
}
return g_steal_pointer(&slirp);
}
static char *
qemuSlirpCreatePidFilename(virQEMUDriverConfigPtr cfg,
const virDomainDef *def,
const char *alias)
{
g_autofree char *shortName = NULL;
g_autofree char *name = NULL;
if (!(shortName = virDomainDefGetShortName(def)))
return NULL;
name = g_strdup_printf("%s-%s-slirp", shortName, alias);
return virPidFileBuildPath(cfg->slirpStateDir, name);
}
int
qemuSlirpOpen(qemuSlirpPtr slirp,
virQEMUDriverPtr driver,
virDomainDefPtr def)
{
int rc, pair[2] = { -1, -1 };
if (qemuSecuritySetSocketLabel(driver->securityManager, def) < 0)
goto error;
rc = socketpair(AF_UNIX, SOCK_DGRAM, 0, pair);
if (qemuSecurityClearSocketLabel(driver->securityManager, def) < 0)
goto error;
if (rc < 0) {
virReportSystemError(errno, "%s", _("failed to create socketpair"));
goto error;
}
slirp->fd[0] = pair[0];
slirp->fd[1] = pair[1];
return 0;
error:
VIR_FORCE_CLOSE(pair[0]);
VIR_FORCE_CLOSE(pair[1]);
return -1;
}
int
qemuSlirpGetFD(qemuSlirpPtr slirp)
{
int fd = slirp->fd[0];
slirp->fd[0] = -1;
return fd;
}
static char *
qemuSlirpGetDBusVMStateId(virDomainNetDefPtr net)
{
char macstr[VIR_MAC_STRING_BUFLEN] = "";
/* can't use alias, because it's not stable across restarts */
return g_strdup_printf("slirp-%s", virMacAddrFormat(&net->mac, macstr));
}
void
qemuSlirpStop(qemuSlirpPtr slirp,
virDomainObjPtr vm,
virQEMUDriverPtr driver,
virDomainNetDefPtr net)
{
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
g_autofree char *id = qemuSlirpGetDBusVMStateId(net);
g_autofree char *pidfile = NULL;
virErrorPtr orig_err;
qemuDBusVMStateRemove(vm, id);
if (!(pidfile = qemuSlirpCreatePidFilename(cfg, vm->def, net->info.alias))) {
VIR_WARN("Unable to construct slirp pidfile path");
return;
}
virErrorPreserveLast(&orig_err);
if (virPidFileForceCleanupPath(pidfile) < 0) {
VIR_WARN("Unable to kill slirp process");
} else {
slirp->pid = 0;
}
virErrorRestore(&orig_err);
}
int
qemuSlirpSetupCgroup(qemuSlirpPtr slirp,
virCgroupPtr cgroup)
{
return virCgroupAddProcess(cgroup, slirp->pid);
}
int
qemuSlirpStart(qemuSlirpPtr slirp,
virDomainObjPtr vm,
virQEMUDriverPtr driver,
virDomainNetDefPtr net,
bool incoming)
{
g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
g_autoptr(virCommand) cmd = NULL;
g_autofree char *pidfile = NULL;
size_t i;
pid_t pid = (pid_t) -1;
int rc;
int exitstatus = 0;
int cmdret = 0;
VIR_AUTOCLOSE errfd = -1;
bool killDBusDaemon = false;
if (incoming &&
!qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_MIGRATE)) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("The slirp-helper doesn't support migration"));
}
if (!(pidfile = qemuSlirpCreatePidFilename(cfg, vm->def, net->info.alias)))
return -1;
if (!(cmd = virCommandNew(cfg->slirpHelperName)))
return -1;
virCommandClearCaps(cmd);
virCommandSetPidFile(cmd, pidfile);
virCommandSetErrorFD(cmd, &errfd);
virCommandDaemonize(cmd);
virCommandAddArgFormat(cmd, "--fd=%d", slirp->fd[1]);
virCommandPassFD(cmd, slirp->fd[1],
VIR_COMMAND_PASS_FD_CLOSE_PARENT);
slirp->fd[1] = -1;
for (i = 0; i < net->guestIP.nips; i++) {
const virNetDevIPAddr *ip = net->guestIP.ips[i];
g_autofree char *addr = NULL;
const char *opt = "";
unsigned prefix = ip->prefix;
if (!(addr = virSocketAddrFormat(&ip->address)))
return -1;
if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET)) {
opt = "--net";
prefix = prefix ?: 24;
}
if (VIR_SOCKET_ADDR_IS_FAMILY(&ip->address, AF_INET6)) {
opt = "--net6";
prefix = prefix ?: 64;
}
virCommandAddArgFormat(cmd, "%s=%s/%u", opt, addr, prefix);
}
if (qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_DBUS_ADDRESS)) {
g_autofree char *id = qemuSlirpGetDBusVMStateId(net);
g_autofree char *dbus_addr = qemuDBusGetAddress(driver, vm);
/* If per VM DBus daemon is not running yet, start it
* now. But if we fail later on, make sure to kill it. */
killDBusDaemon = !QEMU_DOMAIN_PRIVATE(vm)->dbusDaemonRunning;
if (qemuDBusStart(driver, vm) < 0)
return -1;
virCommandAddArgFormat(cmd, "--dbus-id=%s", id);
virCommandAddArgFormat(cmd, "--dbus-address=%s", dbus_addr);
if (qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_MIGRATE)) {
if (qemuDBusVMStateAdd(vm, id) < 0) {
virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
_("Failed to register slirp migration"));
goto error;
}
if (incoming)
virCommandAddArg(cmd, "--dbus-incoming");
}
}
if (qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_EXIT_WITH_PARENT))
virCommandAddArg(cmd, "--exit-with-parent");
if (qemuExtDeviceLogCommand(driver, vm, cmd, "slirp") < 0)
goto error;
if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, &exitstatus, &cmdret) < 0)
goto error;
if (cmdret < 0 || exitstatus != 0) {
virReportError(VIR_ERR_INTERNAL_ERROR,
_("Could not start 'slirp'. exitstatus: %d"), exitstatus);
goto error;
}
rc = virPidFileReadPath(pidfile, &pid);
if (rc < 0) {
virReportSystemError(-rc,
_("Unable to read slirp pidfile '%s'"),
pidfile);
goto error;
}
slirp->pid = pid;
return 0;
error:
if (pid != -1)
virProcessKillPainfully(pid, true);
if (pidfile)
unlink(pidfile);
if (killDBusDaemon)
qemuDBusStop(driver, vm);
slirp->pid = 0;
return -1;
}