[libvirt] [PATCH v2 3/4] qemuMigrationDstPrepareAny: Parse cookie before adding domain onto list

[Michal Privoznik]

There are some checks done when parsing a migration cookie. For
instance, one of the checks ensures that the domain is not being
migrated onto the same host. If that is the case, then we are in
big trouble because the @vm is the same domain object used by
source and it has some jobs sets and everything so recovering
from failed cookie parsing would be needlessly hard.

Signed-off-by: Michal Privoznik <mprivozn at redhat.com>
---
 src/qemu/qemu_migration.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c
index 0317a35246..28ec1f4d50 100644
--- a/src/qemu/qemu_migration.c
+++ b/src/qemu/qemu_migration.c
@@ -2395,6 +2395,20 @@ qemuMigrationDstPrepareAny(virQEMUDriverPtr driver,
         }
     }
 
+    /* Parse cookie earlier than adding the domain onto the
+     * domain list. Parsing/validation may fail and there's no
+     * point in having the domain in the list at that point. */
+    if (!(mig = qemuMigrationEatCookie(driver, *def, origname, NULL,
+                                       cookiein, cookieinlen,
+                                       QEMU_MIGRATION_COOKIE_LOCKSTATE |
+                                       QEMU_MIGRATION_COOKIE_NBD |
+                                       QEMU_MIGRATION_COOKIE_MEMORY_HOTPLUG |
+                                       QEMU_MIGRATION_COOKIE_CPU_HOTPLUG |
+                                       QEMU_MIGRATION_COOKIE_CPU |
+                                       QEMU_MIGRATION_COOKIE_ALLOW_REBOOT |
+                                       QEMU_MIGRATION_COOKIE_CAPS)))
+        goto cleanup;
+
     if (!(vm = virDomainObjListAdd(driver->domains, *def,
                                    driver->xmlopt,
                                    VIR_DOMAIN_OBJ_LIST_ADD_LIVE |
@@ -2412,17 +2426,6 @@ qemuMigrationDstPrepareAny(virQEMUDriverPtr driver,
         priv->hookRun = true;
     }
 
-    if (!(mig = qemuMigrationEatCookie(driver, vm->def, origname, priv,
-                                       cookiein, cookieinlen,
-                                       QEMU_MIGRATION_COOKIE_LOCKSTATE |
-                                       QEMU_MIGRATION_COOKIE_NBD |
-                                       QEMU_MIGRATION_COOKIE_MEMORY_HOTPLUG |
-                                       QEMU_MIGRATION_COOKIE_CPU_HOTPLUG |
-                                       QEMU_MIGRATION_COOKIE_CPU |
-                                       QEMU_MIGRATION_COOKIE_ALLOW_REBOOT |
-                                       QEMU_MIGRATION_COOKIE_CAPS)))
-        goto cleanup;
-
     if (STREQ_NULLABLE(protocol, "rdma") &&
         !virMemoryLimitIsSet(vm->def->mem.hard_limit)) {
         virReportError(VIR_ERR_OPERATION_INVALID, "%s",
-- 
2.18.1