[PATCH v6 08/13] migration: Export tls-[creds|hostname|authz] params to cmdline too

From: Peter Xu <peterx@redhat.com>
To: qemu-devel@nongnu.org
Cc: peterx@redhat.com,
	Leonardo Bras Soares Passos <lsoaresp@redhat.com>,
	Juan Quintela <quintela@redhat.com>,
	Manish Mishra <manish.mishra@nutanix.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	"Daniel P . Berrange" <berrange@redhat.com>
Subject: [PATCH v6 08/13] migration: Export tls-[creds|hostname|authz] params to cmdline too
Date: Tue, 17 May 2022 15:57:25 -0400	[thread overview]
Message-ID: <20220517195730.32312-9-peterx@redhat.com> (raw)
In-Reply-To: <20220517195730.32312-1-peterx@redhat.com>

It's useful for specifying tls credentials all in the cmdline (along with
the -object tls-creds-*), especially for debugging purpose.

The trick here is we must remember to not free these fields again in the
finalize() function of migration object, otherwise it'll cause double-free.

The thing is when destroying an object, we'll first destroy the properties
that bound to the object, then the object itself.  To be explicit, when
destroy the object in object_finalize() we have such sequence of
operations:

    object_property_del_all(obj);
    object_deinit(obj, ti);

So after this change the two fields are properly released already even
before reaching the finalize() function but in object_property_del_all(),
hence we don't need to free them anymore in finalize() or it's double-free.

This also fixes a trivial memory leak for tls-authz as we forgot to free it
before this patch.

Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/migration.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index d17f435d08..aa4185148c 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -4379,6 +4379,9 @@ static Property migration_properties[] = {
                       DEFAULT_MIGRATE_ANNOUNCE_STEP),
     DEFINE_PROP_BOOL("x-postcopy-preempt-break-huge", MigrationState,
                       postcopy_preempt_break_huge, true),
+    DEFINE_PROP_STRING("tls-creds", MigrationState, parameters.tls_creds),
+    DEFINE_PROP_STRING("tls-hostname", MigrationState, parameters.tls_hostname),
+    DEFINE_PROP_STRING("tls-authz", MigrationState, parameters.tls_authz),
 
     /* Migration capabilities */
     DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
@@ -4412,12 +4415,9 @@ static void migration_class_init(ObjectClass *klass, void *data)
 static void migration_instance_finalize(Object *obj)
 {
     MigrationState *ms = MIGRATION_OBJ(obj);
-    MigrationParameters *params = &ms->parameters;
 
     qemu_mutex_destroy(&ms->error_mutex);
     qemu_mutex_destroy(&ms->qemu_file_lock);
-    g_free(params->tls_hostname);
-    g_free(params->tls_creds);
     qemu_sem_destroy(&ms->wait_unplug_sem);
     qemu_sem_destroy(&ms->rate_limit_sem);
     qemu_sem_destroy(&ms->pause_sem);
-- 
2.32.0


