qemu-slirp: register helper for migration

When the helper supports DBus, connect it to the bus and set its ID.

If the helper supports migration, register its ID to the list of
dbus-vmstate ID to migrate, and specify --dbus-incoming when
restoring the VM.
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>

src/qemu/qemu_slirp.c

@@ -18,6 +18,7 @@
 
 #include <config.h>
 
+#include "qemu_dbus.h"
 #include "qemu_extdevice.h"
 #include "qemu_security.h"
 #include "qemu_slirp.h"
@@ -202,6 +203,16 @@ qemuSlirpGetFD(qemuSlirpPtr slirp)
 }
 
 
+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,
@@ -209,9 +220,12 @@ qemuSlirpStop(qemuSlirpPtr slirp,
               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;
@@ -302,14 +316,36 @@ qemuSlirpStart(qemuSlirpPtr slirp,
         }
     }
 
+    if (qemuSlirpHasFeature(slirp, QEMU_SLIRP_FEATURE_DBUS_ADDRESS)) {
+        g_autofree char *id = qemuSlirpGetDBusVMStateId(net);
+        g_autofree char *dbus_addr = qemuDBusGetAddress(driver, vm);
+
+        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)
-        return -1;
+        goto error;
 
     if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, &exitstatus, &cmdret) < 0)
-        return -1;
+        goto error;
 
     if (cmdret < 0 || exitstatus != 0) {
         virReportError(VIR_ERR_INTERNAL_ERROR,
@@ -333,5 +369,6 @@ qemuSlirpStart(qemuSlirpPtr slirp,
         virProcessKillPainfully(pid, true);
     if (pidfile)
         unlink(pidfile);
+    qemuDBusStop(driver, vm);
     return -1;
 }